Nakul Aggarwal -- April 25
Discovering Factorization Surface of Quantum Spin Chains with Machine Learning
Entanglement in quantum many-body systems is required for a variety of quantum information tasks, making it crucial to identify the parameter space in which the ground state is fully separable, known as the factorization surface (FS). We employ symbolic regression (SR) to determine a closed-form expression in the parameter regime corresponding to FS of quantum many-body Hamiltonians. We verify the effectiveness of this method by examining the nearest-neighbor (NN) quantum transverse XY model with additional Kaplan-Shekhtman-Entin-Aharony interactions, for which the FS is well-known. We construct an accurate expression for the FS of the XYZ model and estimate the FS for the long-range XY model. We finally discover FS for the NN XY model with Dzyaloshinskii–Moriya type asymmetric interaction for which FS remains unknown till date.
Sidan A, Conor Larison, Rafael Porto, David Rogerson -- April 4
Iceland
Dilys Ruan -- March 7
Climate Change - Reviewing IPCC AR6 Results
In this talk, I (as a grad student with an astrophysics background) will review some of the key figures and plans outlined in the Intergovernmental Panel on Climate Change Sixth Assessment Report. Although climate change is a global problem that is rooted in the structure of our economy and industries, this assessment hopefully gives us a way forward to focus on reducing the harm. This seminar will also have an interactive portion (so bring your laptops!). We will use the MIT EN-ROADS simulator and act as certain sectors while trying to reduce global emissions below +2 degrees C by 2100.
Gavin Rockwood -- Feb 22
Entanglement Hamiltonians in 1D Free Fermionic Systems
Entanglement Hamiltonians in 1D Free Fermionic Systems
Abstract: I discuss the use and construction of entanglement Hamiltonians as a probe of entanglement using 1D free fermionic systems as an example. The states in question are ground states of critical Ising chains with defects. If one takes a subsystem that contains the defect, the entanglement entropy of that region is largely independent of the defect, where as the entanglement spectrum and thus Hamiltonian is not. The focus of the talk will be the calculations of these entanglement Hamiltonians and the analysis of their defect dependent structure along with their connection to CFT results.
Eric Putney -- Feb 8
Fair Fees for Fellows
Rutgers grad students sacrifice both financial and medical security by accepting prestigious fellowships. On top of that, Rutgers charges grad fellows thousands of dollars in fees every semester. I will present some of our early work with the union on removing these fees and improving the lives of graduate fellows at Rutgers.
Lana Eid -- Dec 7
Cluster Lensing
We aim to use the z=0.725 giant arc lensed by the z=0.375 Abell 370 galaxy cluster in Hubble Frontier Fields data to study the effects of using an extended source model on constraining a cluster lens model. Gravitational lensing by galaxy clusters magnifies and distorts distant galaxies, which can let us study them at higher resolution than otherwise possible.In order to determine the morphology of the source, the observed images need to be de-lensed. Cluster lens models are generally constrained using image positions and assuming point sources. We use giant arcs to study the effects of an extended source model on both the cluster mass model and the reconstructed source galaxy. A giant arc provides more constraints than images from an unresolved point source, but it requires a more complex model that accounts for the structure of the source. We seek to determine whether improvements to the lens model and reconstructed source merit the difficulty of handling the extra constraints.We first present a series of pixel-based source reconstructions for cluster mass models that explore the range of uncertainties in our fiducial model. We additionally compare predicted sources and model arcs from a set of 10 fiducial cluster models from the HFF teams using a simpler delensing code. We then discuss possible avenues to solve the issues we have found in all these models.
Michael Terilli -- Nov 30
Active Learning: Lessons from the Physics Classroom and Picket Line
Kaustubh Roy -- Nov 16
Unfolding the Mathematics of Origami
Origami is the art of folding pieces of paper into a finished sculpture, all performed without cutting or gluing. It encompasses all levels of skill; from napkin swans at restaurants to intricate designs made with hundreds of folds. Behind it all, however, is a rich and varied field of mathematical study, which in the past years has been of considerable interest in numerous fields. My talk is meant to be a small (and fun!) introduction to the mathematics behind origami. We'll go over some simple constructions, motivate some theorems, and make you reconsider everything you thought you knew about folding paper. I'll of course bring along some origami paper for you to follow along (or mess around with) during the talk. Just make sure not to ruin them while eating some delicious Delhi Garden food!
Dilys Ruan and Eric Putney -- Oct 26
Phantasmal and Paranormal Phenomena in Physics — Spooky Student Seminars in Physics and Astronomy at Rutgers (SSSPAR)
Our second SSPAR of the academic year, focusing on the paranormal experiences of members of our graduate student community. Real™ ghost stories welcome ;). If everyone is too spooked, or even too haunted to share their stories, we will watch Hocus Pocus.
Irene Moskowitz -- Oct 12
Mental Health and Mental Hygiene: Developing Tools to Thrive while earning a Physics PhD and Overcoming Impostor Syndrome
Charlotte Olsen and Sabrina Appel -- Dec 2
Equality Issues in Physics
Answering fundamental questions in physics requires the combined effort of the brightest minds the community has to offer, regardless of gender, race, ethnicity, religion, sexual identity, or any other demographic. Yet, in spite of an abundance of interest and ability, few individuals from underrepresented populations in physics and astronomy make it through to a PhD. We will investigate this “leaky pipeline” with the help of numerous recent studies regarding the challenges and obstacles faced by underrepresented minorities in physics and astronomy. We will offer actionable solutions that can be implemented at a range of levels (ranging from individual to department solutions). We will also workshop a number of scenarios to develop strategies for handling different situations in order to work towards an environment where every physicist thrives.
Mitchell Weikert--Nov 11
Radio Search for Dark Matter Annihilation in M31
Indirect detection is a popular method of probing dark matter interactions in which the goal is to search for evidence of dark matter annihilations or decays into standard model particles. Interestingly, a number of groups have found evidence for gamma rays in excess of astrophysical expectations with a morphology and energy spectrum that is consistent with what would be expected from WIMP dark matter annihilating into unstable Standard Model particles. These unstable particles quickly decay producing stable particles, including gamma rays. The excess gamma rays that have been observed come from the central regions of the Milky Way, the Large Magellanic Cloud and Andromeda and the excesses of each galaxy are similar in character. The dark matter models that best fit the gamma rays have dark matter in the mass range O(10 GeV − 100 GeV) annihilating to bottom quarks or tau leptons, but there are popular astrophysical explanations for the gamma rays as well. To help determine whether the gamma rays are from dark matter or something else, we decided to look for evidence of excesses of other stable particles that would be expected to come from dark matter annihilations of this kind. One promising option is an excess of high energy electrons and positrons propagating through one of the galaxies in question. Such electrons and positrons are expected to emit a wide spectrum of radiation through a variety of processes, including radio emission due to synchrotron from accelerating in the interstellar magnetic field. Motivated by the gamma ray excesses, we search for evidence of excess radio emission in Andromeda produced by electrons and positrons from annihilation of WIMPs in the mass range 6 − 500 GeV into b-quarks. We plan to set limits on the annihilation cross section of dark matter by comparing the expected radio signal from dark matter annihilation to 3.6 cm radio data collected by the Effelsberg telescope.
In this talk, I will first give some background about dark matter and the standard model of particle physics. I will then motivate our search by explaining the evidence for gamma ray excesses from dark matter annihilation and discussing the most favored alternative explanation for the excesses. Next, I plan to review the physics that must be modeled to compute the radio signal from dark matter annihilation. Following that, I will justify our choice of data and a region of interest for our study. Then I will discuss the statistical method we are using and show some results that we plan to refine. Lastly I will conclude and share our plans for the rest of the work on this project.
Liam McDermott--Nov 4
Understanding Neurodivergent Physics Identity Through Critical Physics Identity and Disabled Political Identity Frameworks: A Proposal
I propose a study which uses critical frameworks to understand how neurodivergent students come to view themselves as physicists. In this, I propose the use of narrative analysis as a data collection tool to better understand neurodivergent identity formation in physics.
Plamen Kamenov--Sept 23
Introduction to Protected Qubits
Quantum computing with superconducting circuits has made significant strides in the past two decades with the development of the transmon [J. Koch et al. (2007)], a weakly anharmonic microwave antenna with exponential insensitivity to charge noise, which achieves coherence times in the 100 microsecond range. However, the poor anharmonicity of the transmon places a fundamental lower limit on single-qubit gate times. In recent years, a zoo of qubits resistant to charge noise and maintaining large anharmonicity has been developed to replace the transmon. Of particular interest are qubits with higher-dimensional Hamiltonians which feature simultaneous protection against qubit decay and dephasing thanks to the disjoint support of their wavefunctions. I will discuss recent advances and challenges in developing these superconducting qubit circuits.
Pradip Kattel--Sept 16
Open Quantum Systems
As we start to make progress on quantum foundation and use its result to architect novel quantum technologies, we need to scrutinize the idealization in quantum theory carefully. For an example, in the field of quantum computing and quantum information theory, the existence of quantum supremacy is often deduced from the theory of closed and isolated quantum system which obeys the unitary dynamics. But in reality, no quantum system is closed; every system interacts with its surrounding and hence its reduced dynamics is inherently non-unitary. The practical success of quantum information science strictly relies on understanding quantum systems subject to the real-world noisy environment. Properly taking into account the effects of the surrounding, it is important to reexamine the results in more realistic open quantum settings. In this talk, I will talk about some ideas in open quantum systems. I will mostly talk about the established framework of Markovian open quantum dynamics and some basic discussion about the recent progress in
non-Markovian dynamics.
Charlotte Olsen--Sept 9
Mental Health and Mental Hygiene: Developing Tools to Thrive while Earning a PhD
Graduate students report symptoms of anxiety and depression at six times the rate of the rest of the population (Evans el Al., 2018). When dealing with the stresses of graduate school, students frequently experience anxiety or depression even without underlying prior mental health issues. In this talk, we will discuss resources available both through the University and off campus. We will discuss various techniques to help to address both the symptoms and the source of the stress. This talk aims to propose a preventative framework to help de-stigmatize mental health hygiene and create a dialogue around and an environment of community support within the department.
Renna Yi--Apr 22
The Origin of Life
How do we define and demonstrate the transition from non-life to life? The origin of life remains an unsolved scientific puzzle, despite numerous attempts from multiple disciplines. Here I will highlight approaches to the problem from chemistry and physics and whether we are anywhere near solving the problem.
Cheng-Li Chiu--Princeton Physics--Apr 15
2D Material Research Life
Electrons confine in 2D material can have distinct behaviors than in bulk crystal. The electron-electron interaction can easily be enhanced when the effective mass is reduced by lowering the charge density or the increase of the inter electron distance. Many quantum phenomena have been realized in such low dimensional platform such as graphene or TMD and making the 2D material a hot topic. In the talk I will give some introduction to 2D physics and telling the story of my life doing such research. I will also introduce my hometown Taiwan and compare my life there and here.
Xianghan Xu--Apr 08
How Material Synthesis Promotes Physics
Material synthesis is not just a "gray area" between chemistry and physics, but a crucial stepstone to practice exotic phenomena in textbooks experimentally. In this talk, I'll show examples that how new materials unravel physics puzzles, especially our recent work of the meta-stable ferroelectric phase in HfO2 bulk single crystals. The relevant experimental techniques will be introduced in detail. Hope my talk can give you a flavor of what we're doing and inspirations for future research.
Charlotte Olsen--Apr 01
Finding Evidence for Synchronized Star Formation in Local Volume Dwarf Galaxies
Star Formation Histories (SFHs) reveal physical processes that influence how galaxies form their stellar mass. We compare the SFHs of a sample of 36 nearby (D < 4 Mpc) dwarf galaxies from the ACS Nearby Galaxy Survey Treasury (ANGST), inferred from the Color Magnitude Diagrams (CMDs) of individually resolved stars in these galaxies, with those reconstructed by broad-band Spectral Energy Distribution (SED) fitting using the Dense Basis SED fitting code. Metrics for comparing individual SFHs from both methods show overall agreement. For both the CMD and SED methods, the median normalized SFH of galaxies in the sample shows surprising synchronous star formation beginning between 4 and 6 Gyrs ago and continuing to the present day.
Nicodemos Varnava--Feb 25
Everettian Quantum Mechanics
Quantum mechanics (QM) is the best description of reality we currently have. Yet, we don't really understand what is going on behind the scenes. In fact, we decided to hide our ignorance under the rug by postulating the collapse of the wavefunction after a measurement. In this talk, inspired by Sean Carroll's book "Something deeply hidden", I will argue that as physicists we should care more about the foundation of QM and I will present my personal favorite formulation, "Everettian QM" or "Many worlds interpretation of QM". We will see that by taking the wavefunction seriously our classical experience manifests as single worlds whose superposition constitutes the wavefunction of the universe. On a practical level the ongoing second quantum revolution, defined by coherent manipulation of quantum systems, demands a more careful examination of what measurement is. This is exemplified by the famous "Wigner's friend paradox" which I will discuss. I will end my talk with some philosophical speculation about the meta-issue at work. Namely, at the heart of the measurement problem (and the consciousness problem) lies the inability to distinguish the system from the observer, which is the crux of the scientific method. Understanding the philosophical implications should at least help us better define our questions and at best it could be an indicator that a new paradigm shift is needed.
Yi-Shiou Duh from Stanford Physics--Feb 18
Rock Climbing and My PhD Life
Rock climbing is a trendy sport but full of failure and falling. Similarly, PhD degree is the accomplishment of overcoming a series of challenges. It is rewarding to pursue both goals in my PhD life. In the talk, I will invite you to my climbing journeys and share with you some valuable lesson, which is hard to learn elsewhere. Moreover, I will talk about how I combine both my passion together to publish a paper about deep learning and climbing. In the end, I will talk about how rock climbing influences me as a person.
Danny Doucette from Pittsburgh Physics--Feb 4
How can Physics Education Research Improve Equity in Physics?
The field of Physics Education Research (PER) brings methods and frameworks from the social sciences to bear on physics, with the goal of improving student learning. Although PER has traditionally focused on improving instruction, some recent work has focused on the lived experiences and biases that curtail diversity and inclusion in our field. In this talk, I will introduce some themes from equity-focused research in PER. I will highlight some important research results about the causes of inequities, and introduce some research-oriented approaches to improve equity in large public universities in the USA.
Steffie Thayil--Jan 28
Detecting particles with the Compact Muon Solenoid
The Compact Muon Solenoid (CMS) is a general purpose detector on the Large Hadron Collider (LHC) ring at CERN. CMS records the debris from particle collisions at the LHC, using a variety of detector technologies to measure the momentum and energy of different types of particles. This information is then used to reconstruct the physics processes that occurred in the collision. Millions of such collisions are recorded and processed at CMS to make measurements on the Standard Model of particle physics, as well as to search for new physics beyond the Standard Model.
In this talk, we'll discuss the hardware that makes these measurements possible-- the subdetector components, which use various physics phenomena to make energy/momentum measurements; the trigger system, which decides which events to record; and the way these come together to provide a realistic picture of the underlying particle interactions.
Lana Eid--Nov 19
Source Reconstruction of the Gravitationally Lensed Giant Arc in the Galaxy Cluster Abell 370
Gravitational lensing by galaxy clusters provides a unique way to study distant galaxies in higher magnifications than would normally be seen. However, the lensed images we see of high-redshift objects have been warped and distorted, so we need to de-lens the image(s) in order to study the morphology of the source. We aim to use giant arcs to study the effects of using an extended source on both the lens model and the reconstructed source.
Generally, lens models are constrained with lensed images by assuming a simple point source. Spectroscopy can be used to determine which images are from the same source, and the positions of different images are used as constraints in the lens model. A giant arc naturally provides more constraints than images from an unresolved point source, but with this higher level of complexity comes a larger number of parameters to fit, such as the structure of the source in addition to the point-spread function. Our goal is to determine whether any improvements to the lens model and reconstructed source merit the difficulty of handling the extra constraints.
As a specific example, we consider the giant arc in the Abell 370 galaxy cluster, which is at redshift z = 0.375. Raney et al. (2020) used the lensmodel code (Keeton, 2001 and 2011) to model the galaxy clusters in the Hubble Frontier Fields program, and they found from their lens model that the arc is comprised of five merging images of the same source, which is at a redshift of z = 0.725. We used the deflection maps, source position, and image positions from the analysis in Raney (2019) to test different ellipticities and orientations of an extended source and see how it compared to the shape of the observed arc. The next step is to use the pixsrc code from Tagore (2014) to perform a full reconstruction of the source.
Phillip Rechani--Nov 12
A Quest to Image Live Cells at the Single Molecule Level
Optical tweezers were created by Arthur Ashkin in 1970. He demonstrated the effect of light’s momentum on microscopic particles by using two counter propagating lasers horizontally on transparent beads in water. Since then, people have been using optical tweezers on particles of varying sizes (~50nm to 1μm) in various geometries for biological physics and nanophotonics. In Sang-Hyuk Lee’s lab, we use optical tweezers for biological physics. Optical tweezers can be used to measure forces of single molecules such as DNA, RNA or Proteins using various techniques, all of which involve attaching two ends of these molecules to beads and then trapping the beads with lasers. This can measure the spring constants of these molecules as well as folding and unfolding forces and the Gibbs Free Energies of these conformations all as a function of displacement. One of the ultimate goals in our lab is to do chemical sensing at the single molecule level. This would involve trapping a metal “nanostar," a metal nanoparticle with several sharp points on its surface, with a trapping laser, and a probing laser used to get the Raman spectrum unique to neighboring molecules. This concept of using nanostars as chemical sensors is called Surface Enhanced Raman Scattering or SERS. This will, theoretically, allow, chemical sensing inside cells in vivo (while the cell is alive). I will be speaking about the history of optical tweezers, a glance at the physics of trapping particles of different sizes and materials using light, the applications for measuring forces and the goal of using them for metal nanoparticles for chemical sensing.
Ironman Training and Grad School: A personal account of goal setting, perseverance, and work-life balance.
In September 2020, I completed an Ironman Distance Triathlon, a single-day long-distance race consisting of a 2.4 mile swim, 112 mile bike, and 26.2 mile run. Preparing for this event involved balancing 30+ hour training weeks while maintaining progress on my courses and research. Additionally, the Coronavirus brought about race cancellations and other challenges to overcome. Along the way, I learned many lessons that have carried over to my success as a student, including the importance of overall health, structured routines, and sticking to a plan. They say grad school is a marathon, not a sprint, so come hear how literal marathon swim-run-bike training helped me become a better student!
Tsung-Chi Wu--Oct 29
*Recorded Video Link*
*Slides*
Promotion of Equity, Diversity, and Inclusion in STEM fields – Drawing Inspiration from Universities’ and Companies’ Inclusion Statements and Videos
The inequality of gender, sex orientation, and race in science, technology, engineering, and math (STEM) fields has remained constant for decades. For example, a recent study showed that women are 20% more likely than men to leave fulltime STEM employment after their first child [1]. Also, a multilevel regression model demonstrated sexual minority students were 7% less likely to be retained in STEM compared to switching into a non-STEM program [2-3]. Moreover, racial diversity in PhD-level Earth scientists has not improved over the past four decades, with faculty of colour holding only 3.8% of tenured or tenure track positions in the top 100 geoscience departments [4]. These studies suggest the importance of having a workplace that celebrates the diversity of faculty, students, and staff, and an environment that includes, values, and trusts each other. In the talk, I will first reveal several facts about the inequality in STEM fields. After that, together we will read statements and watch videos about equity, diversity, and inclusion from several universities and companies. Hopefully, we can draw inspiration from them and get motivated to promote equity, diversity, and inclusion at the levels of the research group, department, university, and whole academic community.
[1] E. A. Cech and M. Blair-Loy, PNAS 116, 4182-4187 (2019).
[2] J. Freeman, Nature 559, 27-28 (2018).
[3] B. E. Hughes, Science Adv. 4, eaao6373 (2018).
[4] K. Dutt, Nature Geoscience 13, 2–3 (2020).
Charlotte Olsen & Sabrina Appel--Oct 22
*Recorded Video Link*
Women in Physics: A Case Study of Equity Issues in Physics
Answering fundamental questions in physics requires the combined effort of the brightest minds the community has to offer, regardless of gender, race, ethnicity, religion, sexual identity, or any other demographic. Yet, in spite of an abundance of interest and ability, few individuals from underrepresented populations in physics and astronomy make it through to a PhD. We will investigate this “leaky pipeline” with the help of numerous recent studies regarding the challenges and obstacles faced by women in physics and astronomy as a case study of broader equity issues in physics. We will offer actionable solutions that can be implemented at a range of levels (ranging from individual to department solutions). We will also workshop a number of scenarios to develop strategies for handling different situations in order to work towards an environment where every physicist thrives.
Victor Drouin-Touchette--Oct 15
*Recorded Video Link*
*Slides Link*
ARPES: Uncovering the Superconducting Gap
In this presentation, I will survey the experimental technique of angular resolved photo-
emission spectroscopy (ARPES), and its use in the determination of the symmetry of
the superconducting gap in cuprates. ARPES is based on the property of matter that
when exposed to light of frequency ν, electrons will be expulsed from the material if
~ ν ≥ Φ, with Φ the energy needed to delocalize an electron from the surface. Further,
the energy of the collected electron will grow linearly with ν. This effect, explained by
Einstein, can be used to probe the electronic structure of matter.
The intensity of the collected electrons can be mapped out with respect to their mo-
mentum k and their energy ~ ω: I(k, ω). Using interacting electron theory, the intensity
of the electrons hence collected can be related to the spectral function for one-particle
excitation, i.e. the “easiness” to rip an electron out of the dispersion bands in the
material.
After surveying, the experimental challenges of ARPES relating to the condition of
the experimental setup, I will show how its application to Cu gives a purely parabolic
dispersion, as well as showing more minute details. This first example shows the great
resolution of ARPES.
Finally, experimental data of ARPES on lead allows us to directly observe the su-
perconducting gap due to the formation of bound Cooper pairs in the superconductor.
Using that as a stepping point, I will present the data on Bi-2212, a 96K cuprate super-
conductor, and how the analysis of the dispersion reveals the unusual gap symmetry.
Chad Ummel--Oct 8
*Recorded Video Link*
Watch your Back(ground)!—Measuring the Beam-Induced 13C(d,n)14N Background in Underground Nuclear Astrophysics Experiments
The 13C(α,n)16O reaction is the primary source of neutrons for the slow neutron capture process (s-process) of stellar nucleosynthesis, which is responsible for the creation of roughly half of all elements heavier than iron. Due to low yields, the reaction rate is poorly constrained in the astrophysically relevant energy range. As such, measurement of the 13C(α,n)16O cross section is being pursued heavily at high-intensity, low-background accelerator laboratories, primarily in facilities located deep underground. Preliminary neutron energy spectra from a measurement at Oak Ridge National Laboratory’s Multicharged Ion Research Facility (MIRF) showed high-energy background events corresponding to neutrons from the 13C(d,n)14N reaction, resulting from very low, but nonzero deuterium contamination in the alpha-particle beam. The 13C(d,n)14N cross section is many orders of magnitude greater than that of 13C(α,n)16O in the relevant energy range, and its contribution cannot be quantified via blank target runs. Thus, a direct measurement of the 13C(d,n)14N cross section in the energy range of interest is needed. Accordingly, an experimental effort was undertaken to measure the 13C(d,n)14N cross section at laboratory energies between 140 and 250 keV at MIRF. Preliminary results and the implications of this work will be discussed.
Anna Hallin--Oct 1
*Recorded Video Link*
A Taste of High Energy Physics
Welcome to a flavorful talk on high energy physics! The current model for the known elementary particles and their interactions, the Standard Model, is extraordinarily successful. However, we know that there is more to Nature than the particles we have found so far. How can we look for New Physics, using the physics we already know? In this talk we will get to know the flavor sector of the Standard Model, and learn how precision measurements can give us new insights into the nature of potential New Physics.
Wen-Sen Lu--Sept 24
*Recorded Video Link*
*Slides Link*
Marching Toward Quantum Readiness
Having seen recent national funding surges in quantum computing including US, Canada, UK, China, and more, did you ever wonder if quantum industry is going to be just another huge bubble? As one of the major public providers for quantum computing cloud services, IBMQ hosted a 11-days Qiskit free online summer school at the end of August to educate general publics (>4000 participants) from quantum circuit assembly to simple molecular simulations in quantum chemistry. What is its motivation behind all these efforts promoting quantum information education? Have you ever felt frustrated by the extremely unequal number of employees in terms of races and gender in high tech-industry? And if we can travel back in time to correct it, what could be done to prevent this?
In this talk I will try to address above questions by looking back the development of contemporary classical computer, comparing it with the progress of newly born quantum industry, and present what can cloud-based quantum computing services provide to fight against the injustices we are seeing in today's high-tech industries.
Charlotte Olsen--Sept 17
*Recorded Video Link*
Mental Health and Mental Hygiene: Developing Tools to Thrive while earning a Physics PhD
Graduate students report symptoms of anxiety and depression at six times the rate of the rest of the population (Evans el Al., 2018). When dealing with the stresses of graduate school, students frequently experience anxiety or depression even without underlying prior mental health issues. In this talk, we will discuss resources available both through the University and off campus. We will discuss various techniques to help to address both the symptoms and the source of the stress. This talk aims to propose a preventative framework to help de-stigmatize mental health hygiene and create a dialogue around and an environment of community support within the department.
Angkun Wu--Mar. 12
Discussion: the novel coronavirus
We’ll discuss currently prevailing coronavirus--COVID-19 in this SSPAR. We’ll talk about some basics of coronavirus, the history and key biological mechanism. We’ll show a video about the timeline of COVID-19 spreading in China. We’ll show the effective actions to prevent this virus for individuals. In the end, we’ll raise hypothetical questions and encourage further discussions.
Roman Geiko--Mar. 5
Physics and mathematics of topological phases: a review
We shall discuss what is called ``topological order'' and how we distinguish different patterns of topological ordering. There are many points of view on this subject: from condensed matter theory, high energy theory, and mathematics. We shall relate those three and discuss the modern classification of topological phases.
Angkun Wu--Feb. 27
Documentary: Fermat's Last Theorem
Besides normal academic talks for SSPAR, we hope to introduce some historical stroies about physics and math to our audience. In this SSPAR, we'll watch a 45-minute documentary film about the story of proving Fermat's Last Theorem. Fermat's Last Theorem, also called Fermat's conjecture, states that no three positive integers a,b,and c satisfy the equation an+bn=cn for any integer value n larger than 2. This conjecture was proposed by Pierre de Fermat in 1637 in a copy of Arithmetica, where he wrote that he had a proof that was too large to fit in the margin. It was noted as the "most difficult mathematical problem" in the Guinness Book of World Records due to numerous unsuccessful proofs. After 358 years, the first proof was given by Andrew Wiles at Princeton in 1994, which relates modularity theorem and ellipse curve with number theory after 6 years of secretly working.
Aditya Ballal--Feb. 20
Inference of Network Communities using Random Walks
Community structures are very common in real-world networks. For example, social networks such as Facebook, Instagram and Twitter, biological networks such as gene co-expression networks, protein-protein interaction networks or link based networks such as Wikipedia all exhibit pronounced community structure. We propose a novel stochastic method, based on random walks, for community detection on undirected networks with weighted or unweighted edges. The method employs first-passage properties of random walks on networks, providing key statistics of network community structure such as the number of communities and the size of each community after only a small fraction of nodes have been explored. This method provides robust results on large-scale networks in which the complete transition matrix is unavailable due to network size.
Aidan Zabalo--Feb. 13
Critical properties of the measurement induced transition in random quantum circuits
Random quantum circuits have emerged as useful tools in the study of many body quantum chaos. Their simplicity makes them amenable to analytical and numerical techniques while offering insight into the behavior of generic many body systems. In this talk we will discuss the measurement induced transition in the dynamics of entanglement of these circuit models. We will show how the competition between entanglement growth due to chaotic dynamics and entanglement destruction due to local projective measurements leads to a transition dependent on the measurement rate.
Ghanashyam Khanal--Feb. 6
Significance of correlations on electronic structure and lattice dynamics in real materials
The role of electronic correlations in real materials has been an extremely important one. High Tc superconductors, metal to insulator transitions, and more recently twisted bilayer graphene have all brought our attention to the correlation effects on various real systems. In this talk, I'll discuss various avenues the condensed matter community is taking in tackling these problems. And if you feel boring, I'll present some fun facts about mountains towards the end.
Angkun Wu--Jan. 30
Moiré bands in twisted bilayer graphene from the continuous model
Magic angles in twisted bilayer graphene (TBG) are twisted angles of two layers of graphene which induce flat band at half filling (zero group velocity). The superconductivity emerging from TBG at magic angles attracts lots of attention in condensed matter community. People are still searching for the mechanism leading to such induced strongly correlated electronic system. As a background, in this talk, we will introduce the original study of magic angles from MacDonald's work (PNAS 2011 108 (30) 12233-12237), deriving magic angles from the continous spectrum around Dirac cones. We will introduce the physical picture, derive the main results and reproduce the band structure from the coding.
Yixing Fu-- Dec. 5
Semimetals, twist, and irrational numbers
Semimetals are materials with band crossing, where the gapless electronic excitations near the crossing point resembles Weyl or Dirac equation. One of the most studied example is graphene, where people have discovered superconductivity and Mott insulator by twisting the bilayers (dubbed magic-angle twisted bilayer graphene). Such fascinating phenomenon is due to the interplay between semimetallic band structure of graphene and the Moire pattern generated by the twist. In this talk I will introduce a few other simple models of semimetallic systems with quasiperiodic modulation that can also host a transition analogous to the magic-angle effect. Through these simpler models, we will delve into the incommensurate nature of this quantum phase transition, and show some interesting multifractality and number theory behind the physics.
Charlotte Olsen&Sabrina Appel-- Nov. 21
Women in Physics: A Case Study of Equity Issues in Physics
Answering fundamental questions in physics requires the combined effort of the brightest minds the community has to offer, regardless of gender, race, ethnicity, religion, sexual identity, or any other demographic. Yet, in spite of an abundance of interest and ability, few individuals from underrepresented populations in physics and astronomy make it through to a PhD. We will investigate this “leaky pipeline” with the help of numerous recent studies regarding the challenges and obstacles faced by women in physics and astronomy as a case study of broader equity issues in physics. We will offer actionable solutions that can be implemented at a range of levels (ranging from individual to department solutions). We will also workshop a number of scenarios to develop strategies for handling different situations in order to work towards an environment where every physicist thrives.
Angkun Wu-- Nov. 14
Density-Matrix Renormalization Group (DMRG) and Numerical Renormalization Group (NRG)--A brief introduction
The study of strongly correlated quantum system deals with large lattice system sizes and interaction, which is difficult due to the exponentially increasing Hilbert space for many-body wavefunction. The birth of DMRG and NRG provides us with power numerical tools to tackle such problems. While DMRG is normally intended for 1D systems and NRG focuses on impurity problems, their numerical renormalization of degrees of freedom share the same spirit in truncating the Hilber space. I'll introduce the basic idea of these two numerical methods, e.g, Matrix product states (MPS), and their limitations.
Tsung-Chi Wu-- Nov. 7
Superconductor and Topological Insulator – Emergent Quantum Materials in Condensed Matter Physics
Starting from metals and insulators, I will first talk about why some materials are conductive while some are not. Two interesting quantum materials will then be discussed. One is topological insulator, which is insulating inside the bulk but conductive on the surface (or edges) owing to the topology of the system. The other is superconductor, which shows zero resistance below certain temperature (Tc). Several types of superconductors, including BCS superconductors and high-Tc superconductors, will be introduced, and the recent experimental effort on room temperature superconductivity will also be discussed. Last, I will introduce Condensed Matter Physics, illustrating how the general idea, “More Is Different,” leads to emergent quantum phases and makes Condensed Matter Physics one of the most popular and prospective areas in physics.
Yukun Yao-- Oct. 24
Experimental Mathematics, Puzzles, and the Brave New World
In this talk we will go through the experimental approaches to several mathematics problems, e.g., parking functions, peaceable queens, quicksort algorithms or even combinatorial game theory. And then we will solve some puzzles together, which should be interesting. After admiring the beauty of the abstract world, we would like to come back to our concrete world, see some landscape pictures and guess where the pictures were taken. This talk is intended to be casual and fun. No prior knowledge of mathematics or physics is needed.
Steven Clark-- Oct. 17
Search for Exotic Particles Using Neural Nets at the CMS Experiment
Machine Learning techniques are becoming increasingly popular for problems across a wide variety of industries. In High Energy Physics, ML offers the possibility of reconstructing particles where traditional methods fail. Here we explore the use of Convolutional Neural Networks to identify events in highly-merged two-photon final states. These techniques will be applied to the search of new Beyond Standard Model particles and may open the door to unexplored areas of physics. For the second half of the talk, I will discuss my experience with and general info about the NSF Graduate Research Fellowship. I will provide some application tips that will be especially important to first and second year graduate students. The application deadline this year is October 25 so there is still time to apply.
Ziming Ji, Princeton--Rm 112, Oct. 10
NonLocal Nonlinear Sigma Model
Non-linear sigma models are quantum field theories where the fields are regarded as the coordinate of a target space. They are well-studied in the past 60 years. In particular, a similar philosophy makes its connection to string theory useful. For example, the 1-loop conformal invariance of the 2d non-linear sigma model indicates the target space Einstein equation in the vacuum (Friedan 1980). Here we consider a certain non-local variation of the non-linear sigma model, where the Lagrangian density is proportional to the geodesic arc length, which is a bilocal object. The action of the theory is then obtained by integrations of the Lagrangian density over two independent position variables. We study the RG of the theory at 1-loop and beside reproducing Friedan's result, we find that, in odd dimensions, the theory is not renormalizable. The extra terms generated there is the laplacian of the geodesic arc length. I will discuss several aspects of the non-local non-linear sigma model.
Based on work with S. Gubser, C. Jepsen, B. Trundy, and A. Yarom.
Charlotte Olsen--Oct. 3
Mental Health and Mental Hygiene: Developing Tools to Thrive while earning a Physics PhD
Graduate students report symptoms of anxiety and depression at six times the rate of the rest of the population (Evans el Al., 2018). When dealing with the stresses of graduate school, students frequently experience anxiety or depression even without underlying prior mental health issues. In this talk, we will discuss resources available both on and off campus. We will discuss various techniques to help to address both the symptoms and the source of the stress. This talk aims to propose a preventative framework to help destigmatize mental health hygiene and create a dialogue around and an environment of community support within the department.
Ahsan Khan--Sep. 26
Symmetries in Quantum Mechanics
This talk will be about symmetries and their quantum realizations. Symmetries and the groups that encode them play a crucial role in physics. In classical physics the use of symmetries allows one to identify the most important degrees of freedom, thus allowing one a better handle on the equations of motion. In quantum mechanics they play an equally important role, however things are a little more subtle. Because a wave function can be multiplied by a constant phase without changing any of the observable quantities, a symmetry needs to be realized only "projectively". This simple observation allows one to explain many quantum phenomena including the existence of half-integer spin particles.
Angkun Wu--Sep. 19
General graduate life discussion panel
We will have a panel/open discussion with students from different fields who wish to share their experiences of the graduate program thus far. We'll have a topic guidance from the survey. This is especially beneficial for the first-year students as well as all those who have confusions in graduate life.
Robert Young
Why Should Geneticists Have All the Fun? Exploring the Physics of DNA
The pioneering works of Rosalind Franklin, James Watson, and Francis Crick are shining examples of just how dominate a role physics plays in elucidating details of DNA. The DNA replication products expressed from ~2% of all genetic material arise not only because of the base-pair sequence but also from the structural configuration of the double helix. In addition to the commonly known and dynamic chromosomal structures of DNA, much smaller circular structures occur across multiple cell types whose properties are poorly understood. The optimized states from an elastic energy model may offer insights into these unknown properties. The energy minimization calculations performed at the base-pair step level make use of rigid body parameters that describe the orientation and displacement between the nth and nth+1 base-pairs. This talk will showcase studies of a 336 base-pair sequence of DNA specifically engineered for drug delivery and a 1014 base-pair sequence from a parasite implicated in sleeping sickness. Further studies include imposing specific deformations and constraints to the polymer, such as the addition of nucleosome proteins to the DNA circles or rotating each base-pair in the circle about an arbitrary axis, to explore possible optimized state variations.
Nikhil Tilak
Tear, twist and stack
Using the state-of-the-art nano-fabrication techniques, layered crystalline 2D materials like Graphene can be stacked on top of each other like lego pieces to form 2D heterostructures. While stacking these materials, we also have the choice of twisting them with respect to each other. This twisting degree of freedom can profoundly affect the Physics in these materials and give rise to Moire patterns, unexpected metal-insulator transitions [1] and, as was shown recently [2], unconventional superconductivity. I will attempt to go over some of the concepts involved in both fabricating and characterizing these heterostructures with Electrical Transport and Scanning Tunneling Microscopy.
[1] Correlated insulator behaviour at half-filling in magic-angle graphene superlattices -Jarillo-Herrero et al (Nature Physics, April 2018)
[2]Unconventional superconductivity in magic-angle graphene superlattices -Jarillo-Herrero et al (Nature Physics, April 2018)
Heather Garland
Experimentally exploring surrogate transfer reactions to determine (n,γ) reaction rates
The rapid neutron capture process is understood to be responsible for the creation of about half of the elements heavier than iron. Astrophysical models of nuclear abundances are dependent on (n,γ) cross sections and branching ratios. Experimental nuclear physics measurements of (n,γ) rates are necessary to reduce uncertainties in these values. However, most of the isotopes of interest along the r-process path are unstable and are too short lived to create a solid target for direct measurements of neutron capture cross sections. A proposed method of constraining compound (n,γ) cross sections is to use the surrogate reaction method with a light ion transfer reaction such as (d,pγ). Recently, the (d,pγ) reaction in normal kinematics was validated as a surrogate for the (n,γ) reaction [1]. To measure (d,pγ) with radioactive ion beams (RIBS) the Gammasphere ORRUBA (Oak Ridge Rutgers University Barrel Array) Dual Detectors for Experimental Structure Studies (GODDESS) was developed. This talk will present an overview of GODDESS and preliminary results.
[1] A. Rakiewicz, J.A. Cizewski, J.E. Escher, G. Potel, J.T. Burke, R.J. Casperson, M. McCleskey, R.A.E. Austin, S. Burcher, R.O. Hughes, B. Manning, S.D. Pain, W.A. Peters, S. Rice, T.J. Ross, N.D. Scielzo, C. Shand, and K. Smith. Towards neutron capture on exotic nuclei: Demonstrating (d,pγ) as a surrogate reaction for (n,γ). Physical Review Letter, 122, 2019.
Adam Broussard
Starburst! - Looking at Galaxies as Stellar Factories
Our understanding of how galaxies form and evolve over time heavily relies on how they form stars. Do galaxies form stars in fits and starts, or continuously over time? In this talk, I review the primary components of galaxies before diving into the the processes astronomers use to measure star formation rates across various timescales in galaxies. After gaining a basic understanding of star formation rate measurements, I discuss my research in determining the degree of stochasticity in galaxy star formation rates based on star formation rate indicators associated with various timescales using both theory and simulated data. Finally, we will take a look at the results, their implications for galaxy evolution models, and potential sources of error, such as incorrect measurements of galaxy dust content.
Aditya Ballal
Enzyme Evolution and Emergence of Novel Catalytic Functions
Enzyme evolution underlies major expansions of metabolic complexity with profound biological implications. In this talk, I will discuss emergence of cyclization reactions catalyzed by terpene synthases. Cyclic terpenes mediate numerous biological functions in modern plants and provide bioactive compounds for human use, including artemisinin, the most effective treatment for malaria currently available. Guided by the available structural, kinetic, and sequence data, we have constructed mutant libraries which include combinations of amino acids responsible for inducing cyclization reactions in an enzyme that produces E beta-farnesene, a linear hydrocarbon chain. We have used measurements of kinetic rates and mass spectrometry in order to assess catalytic efficiency and specificity of the mutant enzymes. Inspired by spin glass models adapted from statistical physics, we have developed a model which predicts properties as a function of enzyme sequence. Using this model we have inferred evolutionary patterns of enzyme energetics. We have also developed a bio-physical model on fitness of an enzyme based on its catalytic properties. Our studies provide quantitative insights into evolutionary dynamics of a major enzyme family, and highlights the importance of epistasis.
Charlotte Olsen & Sabrina Appel
Women in Physics: A Case Study of Equity Issues in Physics
Answering fundamental questions in physics requires the combined effort of the brightest minds the community has to offer, regardless of gender, race, ethnicity, religion, sexual identity, or any other demographic. Yet, in spite of an abundance of interest and ability, few individuals from underrepresented populations in physics and astronomy make it through to a PhD. We will investigate this “leaky pipeline” with the help of numerous recent studies regarding the challenges and obstacles faced by women in physics and astronomy as a case study of broader equity issues in physics. We will offer actionable solutions that can be implemented at a range of levels (ranging from individual to department solutions). We will also workshop a number of scenarios to develop strategies for handling different situations in order to work towards an environment where every physicist thrives.
Ethan Cline
How does the physics community decide the accepted values of fundamental physical constants?
Between 2006 and 2010 the accepted value of the fine structure constant was shifted by 6.5σ. During the same period, two new high precision measurements of the gravitational constant G caused a 20% increase in the error bar of the accepted value of G. New high precision measurements of the neutron lifetime and proton radius created the “neutron lifetime puzzle” and the “proton radius puzzle” due to inconsistencies between new and old data. Shifts in fundamental constants are surprisingly commonplace in the imprecise world of high-precision physics.
CODATA determines the recommended value of all fundamental physical constants, like those mentioned above, and publishes reports on how they calculate their values. I will discuss how CODATA does their math (and discards dozens of results) and how they are strongly limited by quoted uncertainties from experimental and theoretical papers. I will also discuss how quoted uncertainties are not correct, how author bias significantly influences final results, and the extremely difficult job CODATA has of extracting definitive values from hundreds of papers. These issues will all be discussed in the context of the CODATA 2010 report on the values of fundamental physical constants found here.
Kyle Dettman
Dungeons & Dragons: A History and Treatise
So much of popular culture in recent years has drawn heavily from so called “Geek Culture”. In this talk I will present a foray into one aspect of this culture, the tabletop role-playing game Dungeons & Dragons. I will discuss its beginnings, rise, and fall as well as the plights of its creators. This historical background will hopefully provide insight as to what made the game such a phenomenon and how it drew its harshest critics. I will also provide an overview of the game itself; a description of the many different versions as well as some of the hallmark features that have, in some cases, become synonymous with the game itself. Finally, I will look at the impact D&D has had on culture at large and link it back to sources more familiar to the layperson.
Charlotte Olsen, Konrad Genser & Willow Kion-Crosby
Perspectives on Mental Health as a Graduate Student
With the competitive nature of physics graduate school, stress is an inevitable factor. Although every student is subject to this pressure, each personal experience has the potential to differ greatly. This talk will offer several perspectives on the topic of maintaining mental health as a graduate student starting with a general presentation of the statistics and a brief look at available resources to students. We will then discuss the successes and failures of various strategies to maintain mental health taken by several students, with an emphasis on the diversity of experiences.
Seminar slides can be found here.
Travis Dore -- Feb 7th
A Crossover at a Physics Crossroads: The Quark Gluon Plasma
Since it's discovery, the Strong force interaction has demonstrated extraordinary elusiveness in being fully described and understood. To this end, the Quark Gluon Plasma (QGP) is an excellent probe to the inner workings of Quantum Chromodynamics (QCD), the field theory which describes the Strong interaction. With it's tiny shear viscosity to entropy density ratio of ~ .08, as well as being the only system for which we have seen evidence for the deconfinement of quarks, the QGP is a unique state of matter that is theoretically and phenomenologically interesting. The study of the nature of the fluid along with its transition to confined hadrons is necessarily a crossroads of many different areas of physics. I will give an overview of the field with emphasis on the hydrodynamical description of the QGP and how it is a crucial component to understanding its properties.
Willow Kion-Crosby
An Ancient to Modern History of Physics
Human beings have strove to explain the world through various means since prehistory. Some of these early attempts showed similarity to modern physics in terms of the questions addressed. However, the method of examination has greatly evolved into what is known today as the scientific method. For this talk, we will follow history from ancient (~600 BC) to modern times and take a close look at how the study of physics has changed over time with explicit examples of the questions addressed and answers given. Many of these results will be familiar to our everyday lives as students of physics.
Daniel Brennan
Quantum Gravity, Information, and Black Holes
In this talk we will explore some current topics on studying black holes in quantum gravity. The goal will be to forgo any discussion of the AdS/CFT correspondence and to motivate the application of quantum information techniques to quantum gravity. With time permitting, we will discuss the evaporation of black holes, the information paradox, and traversable wormholes.
Humna Awan
Probing Dark Energy via Galaxy Clustering: Systematics and Improved Estimators
Dark energy (DE) is a leading candidate to explain the cosmic acceleration. Upcoming large galaxy surveys (e.g., the Large Synoptic Survey Telescope, LSST) will enable access to an unprecedented amount of data, allowing us to constrain the nature of DE (among many other things!). I will specifically talk about how we can use galaxy clustering to probe DE and how the science is entering a different regime given the statistical power of LSST. I will discuss an example systematic that we have to care about if we are to fully exhaust the statistical power of LSST, followed by a discussion of an improved estimator for measuring galaxy clustering aimed at fully utilizing the large statistical sample in the presence of systematic uncertainties.
Peter Doze
Optical Conformation of High Signal-to-Noise Planck Cluster Candidates
We report on the results from our galaxy cluster search from the high signal-to-noise end of the second all-sky Planck Sunyaev-Zel’dovich (SZ) catalog (PSZ2). Through deep, optical imaging from the Kitt Peak National Observatory 4m Mayall telescope we identify the richest clusters through visual inspection and other methods. A galaxy cluster is confirmed if it is both rich (based off the number of members within 1 Mpc of the brightest cluster galaxy) and within 5 arcminutes of the PSZ2 position. From the 85 unconfirmed PSZ2 candidates we observed, we find 15 galaxy clusters (0.13 < z < 0.74), 12 of which were not previously recognized as the Planck cluster counterpart in the literature. We explore three possibilities for the low confirmation purity: that cluster counterparts are at too low or too high redshift, or are obscured by the Milky Way. We find that these options in total cannot account for the low confirmation fraction, which leads us to suggest that many of the high signal-to-noise unconfirmed PSZ2 candidates are not reliable SZ clusters.
Nicodemos Varnava
Topological band theory
At the foundation of solid-state physics lies band theory. Band theory helped us explain many physical properties of solids, such as electrical resistivity and optical absorption and brought theory and experiment hand to hand. In the last decade, the discovery of topological crystalline phases of matter, made us reevaluate and deepen our understanding of band theory in a profound way. We now understand that bands are topological objects and we can classify them in district topological classes. Some of these classes exhibit unique responses that are quantized and robust against perturbations making them desirable in applications. In this talk, I will present a new and exciting approach to band theory that has been fully developed in the last year and already resulted in the prediction of thousands of new topological materials. I will be focusing on conveying an intuitive understanding of the underlying concepts without overwhelming people with math.
Becca Toomey
Low Energy Measurement of the 13C(α,n)16O Reaction for s-process Nucleosynthesis
The slow neutron capture process (s-process) is a key mechanism in heavy-element synthesis, and is responsible for approximately half of the heavy elements over 56Fe. It creates elements along the line of beta-stability via neutron capture and beta decay in low neutron flux environments such as low-mass asymptotic giant branch stars. The dominant source of neutrons for the main branch of the s-process is the 13C(α,n)16O reaction, which occurs at stellar temperatures of ∼0.1 GK (∼200 keV). This makes direct measurement of the reaction rate in the Gamow window (∼140−230 keV) experimentally challenging due to the low yields and high beam currents required. There have been international efforts to measure this reaction at astrophysically relevant energies utilizing different experimental techniques. One recent measurement, performed at Oak Ridge National Laboratory, utilized a quasi-spectroscopic approach to neutron detection with the aim of reducing uncertainties in current measurements. The experimental challenges and techniques involved with the measurement of this reaction will be discussed.
Jack Hay
Galactic Archaeology: Investigating the Milky Way with Black Hole Microlenses
There is a dark mystery in the Milky Way -- where are the black hole remains of the first stars? To answer this question will require a brief history of "galactic archeology." We will dig through layers of ancient stellar populations to reconstruct the past, we will take core samples of the Milky Way utilizing the phenomenon of gravitational microlensing, we will measure the positions, velocities, masses, and compositions of the mystery lens objects, and we will catch the first glimpse of microlensed spectra recorded by the Southern African Large Telescope.
Aniket Patra
A Study in Nonequilibrium
In our universe almost everything is out of equilibrium. With the improvement of experimental techniques we are now able to probe more and more truly nonequilibrium phenomena. Some of these are explicitly time dependent, whereas some have dissipation and external forcing. One can not explain the outcomes of these experiments by doing a perturbation over an equilibrium state. Thus it has become increasingly important to develop unconventional theoretical framework to study such out of equilibrium processes. In this talk I will give an overview of the field by examining two very different problems -- (1) Multistate Landau-Zener Problem, and (2) Two Atomic Clocks Coupled to a Bad Cavity.
Kartheik Iyer
What can we learn from the Star Formation Histories of galaxies?
The Star Formation History (SFH) is a record of when a galaxy formed its stars. Physical processes that regulate galaxy growth - inflows and outflows of gas, mergers, supernova explosions and more - leave imprints in the SFH. Studying the SFHs of galaxies across a range of epochs thus gives us insights into galaxy evolution, and the mechanisms responsible for it. Well motivated analysis techniques allow us to infer the characteristics of SFHs using multiwavelength observations from large galaxy surveys. This allows us to better estimate quantities like the masses of galaxies and the rates at which they are forming stars. Tracing back galaxies in time along their SFHs allows us to estimate these quantities not only at the epoch of observation but also at previous epochs. Additionally, looking at SFHs across different simulations allows us better understand how different physical processes affect galaxy growth and set the diversity in galaxies we see in the universe today. Finally using observations in conjunction with simulations allows us to set useful constraints on the relative strengths of the processes that shape galaxies.
Victor Drouin-Touchette
How to efficiently throw a dice and simulate phase transitions.
In this presentation, I will present various Monte-Carlo techniques used to simulate the phase transitions. As a first example, we will see how one can see all the features of a second-order phase transition through the Ising model. I will then explore other important Monte Carlo techniques such as global updates, overrelaxation steps, and parallel tempering. Although using these techniques on the Ising model is like opening a peanut with a sledgehammer, we will see that in the case of certain models, such as the hexatic-nematic XY model, these techniques are crucial to accurately describe the phase diagram.
Willow B. Kion-Crosby
Diffusion on Complex Networks and what it can tell us about Epidemiology and Wikipedia
What can be determined about a complex landscape or network by moving through it in the most unintelligent way? This talk will answer this question by presenting a formalism which combines Bayes' theorem with random walk theory. We will then delve into applications in the worlds of computer science and life with an emphasis on epidemiology.
Graduate student advisory panel.
This SSPAR was in the structure of an advisory panel, rather than the traditional presentation. Several of the senior students discussed both their personal experience and gave general advice on the dos and don'ts of physics graduate school. This was an open discussion, not a lecture.
Aaron Yung
How little SAMURAI study the Universe by GUREFTing m-TUREEs
Come join me for an hour-long storytelling section which I tell you everything you need to know about the Jame’s Webb Space Telescope — the long-anticipated successor to Hubble! What do we expect to see and to learn with it? And of course I will also prepare you with a crash course on modern cosmology and wrap up with what semi-analytic modelists are doing to prepare for the upcoming excitement.
Kosta Morfesis
Dynamical Mean Field Theory for Strongly Correlated Systems
In this talk we'll discuss the theory, application, and uses of Dynamical mean field theory (DMFT). We'll begin with a brief introductory example of mean field theory for the classical Ising model. From there we'll look towards discussing mean field theory for a specific quantum system, the Hubbard model. Approximating this model will lead towards a mapping of our many body problem to a simpler impurity problem. From here the DMFT assumption of local lattice interactions will be asserted. Subsequent to the theory, we'll look at the application and successes of DMFT in describing strongly correlated systems.
Daniel Brennan
Confinement: A Confinement Story
Confinement is one of the largest outstanding problems in quantum physics. This describes the curious phenomenon that quarks do not appear in nature by themselves. This talk will review some of the basics and give a broad overview of some modern developments in the subject.
Kyle Dettman
Dungeons & Dragons: A History and Treatise
So much of popular culture in recent years has drawn heavily from so called “Geek Culture”. In this talk I will present a foray into one aspect of this culture, the tabletop role-playing game Dungeons & Dragons. I will discuss its beginnings, rise, and fall as well as the plights of its creators. This historical background will hopefully provide insight as to what made the game such a phenomenon and how it drew it harshest critics. I will also provide an overview of the game itself; a description of the many different versions as well as some of the hallmark features that have, in some cases, become synonymous with the game itself. Finally, I will look at the impact D&D has had on culture at large and link it back to sources more familiar to the layperson
Victor Drouin-Touchette
ARPES study of unconventional superconductors: a review
Angular-resolved photoemission spectroscopy (ARPES) is an experimental tool in the study of quantum materials that has steadily risen since the 1980s to become one of the key methods to probe materials. In this talk, I will review the basic concepts of electron spectroscopy and its link to the spectral function. We will then look at the experimental challenges, what a set of ARPES data can tell us about the material, and recent progress made by ARPES studies. Its role in the study of unconventional superconductivity will be reviewed.
Ethan Cline
Applications of Electron Beams: Electron Microscopes to Deep Inelastic Scattering.
Electron beams are used in a wide variety of physics applications from studying material properties with Electron Microscopes to studying Parton Distribution Functions at electron accelerators around the world. The history and development of electron beams will be discussed starting with the discovery of the electron and continuing on to the proposed Electron-Ion Collider. I will also delve into electron beams in astrophysics and how these beams can provide important constraints for Chiral Effective Field Theory. Some time will also be devoted to electron beams in commercial applications, including electric arc furnaces, solar cell production, and 3D printed rocket engines capable of reaching orbit.
Jay Cushing
Bundle Up : Making Connections...
We will present a slew of abstract definitions, ranging from fiber bundles to connections. After building a working dictionary of terms through simple examples, we will reveal that these mathematical objects are actually quite familiar to the working physicist, playing integral roles in general relativity, gauge theory, and condensed matter. By the talk's end, members of the audience will find themselves sewn into the modern language and warm for winter.
Elaad Applebaum
Liquid State Seminar
The basic physics and chemistry of the distillation process will be presented, followed by a discussion of the various categories of distilled spirits and their attributes.
Fangdi Wen
Modern digital painting
As technology develops, many traditional arts also changed. When it comes to painting, the emergence of digital painting have greatly increased the efficiency for people doing illustration, 3G design as well as animation. For most painting lovers, digital painting makes it cheaper and easier to express themselves through painting. Here I’ll give an overview about what I know about both professional digital painting and some typical drawing styles, and give some good examples of successful works.
Ramon Sharma
Observations of Feedback Processes from Active Galactic Nuclei.
There is building evidence which suggests that many galaxies are highly influenced by the presence of an active galactic nucleus (AGN) at their center. This highly luminous and compact region is thought to heat and drive out gas from the surrounding galaxy via a number of feedback mechanisms, which ultimately allow the AGN to couple to the host galaxy and co-evolve. I look at the motivations behind studying AGN feedback, evidence of feedback occurring in the near and distant universe, and how it will be studied in the future.
Aidan Zabalo
Stability Analysis of a Quantum Quench in a P-wave Superfluid.
The search for a robust platform capable of quantum simulation and computation has led to a growing interest in superfluids with p + ip pairing symmetry. These superfluids are expected to possess zero-energy Majorana bound states which could exhibit the non-abelian statistics necessary for a topological quantum computer. In this talk, we investigate the non-equilibrium dynamics of the two dimensional BCS Hamiltonian with p-wave symmetry. We perform numerical simulation of a system which has undergone a quantum quench of the BCS order parameter. It is known how a system which begins in a p + ip state of the p-wave Hamiltonian evolves, but we would like to investigate the stability of trajectories whose initial conditions deviate slightly from those of the p + ip state. These dynamics can potentially be realized in ultracold gases and could provide experimental verification to the predicted behavior.
Harry Sims
Probing nuclear structure around neutron number 82 with (d,p) reactions.
Models of nuclei far from stability rely heavily on their single particle structure, which constrains the location and nature of nuclear states. The Shell model predicts magic numbers of protons and neutrons which form shell closures in stable isotopes, analogous to noble gases in atomic physics. As studies move towards unstable nuclei, more experimental data is needed to provide these constraints. With the use of RIBs (Radioactive Ion Beams) in inverse kinematics, experiments can populate states in unstable nuclei and probe their characteristics through (d,p) reactions. This presentation will include the methods used to extract excitation energies, spins, parities and spectroscopic factors of populated states in neutron rich nuclei around the N=82 region. The 132Sn(d,p)133Sn reaction will be discussed, showing the single particle states above the N=82 neutron gap, as well as preliminary results for 134Xe(d,pg)135Xe which utilizes both charged particle and gamma ray detection in coincidence.
Nicodemos Varnava
Topological Axion Insulators
The topological classification of matter, introduced a paradigm shift in understanding quantum phases of matter. An example of a topological classification is based on the Chern-Simons axion coupling, a topological invariant determined from the ground state of a crystal. After providing an overview of the basic concepts behind the topological classification of matter, i will introduce axion insulators. Finally i will describe my preliminary results working with Prof. Vanderbilt to study a minimal tight-binding model for the pyrochlore structure.
Raghav Kunnawalkam Elayavalli, John Wu, and Kartheik Iyer
How to teach(learn) physics to(from) our laptops?
[slides]
With the advent of high performance computing, machine learning has been widely adopted by several communities to help with increasing efficiency/speed and in some cases even to aide in solving long standing problems. Physics is no exception with machine learning algorithms helping in several areas of current research for example in astronomy, cosmology and high energy physics to name a few. We begin the talk with a general introduction to neural networks architecture and highlight a few of the models that are in vogue. As physicists, often we deal with issues where given a dataset, one has to either classify it amongst a basis of known phenomenon or extract information by employing regression techniques. We proceed to talk about both these general type of problems and provide examples of ML models that at times end up learning distinctions without being explicitly told, which might be scary. Finally, we will show a selection of problems and quiz the audience on the type of ML model or just simple statistics one would use to solve them.
Ethan Cline and Anna Barcy
The Union and You!
In January the union will begin renegotiating the university’s graduate student contract. These negotiations include raises, decreased insurance costs, and hopefully more plentiful and stable TA/GA lines for our department. For this SSPAR we will discuss details of the contract negotiations and the funding situation for our department.
Anthony Frachioni
Maintenance of Mental Health as a Graduate Student: Addressing a Silent Epidemic
An overview of the empirical prevalence of mental illness among graduate students in science is presented, with a particular focus on depression and suicidal ideation. Methods for addressing mental hygiene are discussed, in addition to resources for those seeking care at Rutgers and generally.
Victor Drouin-Touchette
Emergence of Competing Order in Liquid Crystals
In this talk, I will present the Berezinskii-Kosterlitz-Thouless phase transition, a first insight into a phase transition in which there is no long-range ordering, but rather one in which topological objects, vortices, influence the dynamics. After introducing the subject, I will show how this applies to the theory of melting of 2D crystals, with finally a word about my own research on a generalized BKT model.
Pouya Asadi
Non-Relativistic Effects in Dark Matter Model Building
After an informal introduction to some aspects of field theory and dark matter model building, I will talk about how we can start from relativistic quantum field theory and obtain a non-relativistic description of forces, potentials, and their bound states. I will then go over some non-relativistic effects, namely Sommerfeld enhancement and capture to bound states, that can affect the behavior of dark matter candidates today. Finally, I will focus on a particular dark matter model, which is historically motivated by supersymmetry, and specifically study its bound state spectrum.
Ethan Cline
Pi-N Scattering: Recycling, turning a systematic error into an experiment
I will present an overview of Chiral Perturbation Theory (ChiPT) and how it can be useful for experimentalists and calculating physical observables. There will also be discussion of the MUSE experiment and how the pion-nucleon scattering background in that experiment can be used to expand the existing low-energy data set. The relationship between ChiPT and pion scattering will be discussed at length.
Carl Mitchell
How I Became a Sellout (and You Can Too!)
Not all graduate students are destined to continue along the academic path. Many of us choose to leave the field of physics in pursuit of jobs in industry, journalism, advocacy, and teaching. Each week, our department imports several guest speakers who have been successful in academia, but other stories are much more rare. Over the past year, I've documented my background research into leaving academia as well as my personal journey to obtaining a job in data science. In this talk, I'll share it all with you, and I'll try to do it in a way which doesn't make me sound like a shill for a data science incubator.
Conan Huang
Fountain Pens: A Timeless Classic
Fountain pens or FP are used in all sorts of industrial applications and have been a cornerstone of theory work. We show the historical and practical functions of the FP. We also explore the state space available for FP's in this talk along with the connections between these states along with the connection of certain liquid states.
Victor Drouin-Touchette
Liquid crystals, 2D Coulomb gas and superfluids: insight into universality
The universality of certain physical phenomenon will be explored. First, we will get a quick look at various systems that seem unrelated: the classical XY model for ferromagnetic spins, superfluids, liquid crystals near their melting transition and the 2D Coulomb gas. Though a brief introduction to the Renormalization Group, we will see that those systems present the same universal phase transition: the Kosterlitz-Thouless phase transition.
Ghanashyam Khanal
Physics of strongly correlated systems with transition metals
From large gap insulators to systems with metal-insulator transitions, transition metals (TM) and their compounds possess many specific and unusual features. They display a lot of interesting phenomena such as colossal magnetoresistance, magnetoelectricity and high Tc superconductivity. TM compounds are also the basis of the physics of systems with strong correlations -an area of extensive modern day research. In this talk, I will try to shed some light on some interesting details about TM compounds from Dynamical Mean Field Theory (DMFT) perspective.
Anthony Frachioni
Technical Aspects of the Production of Modern Music
We present a brief overview of the pipeline of hardware and software involved in modern music production.
Willow Kion-Crosby
Principle Causes of Codon Bias: Gene evolution modeled as a first passage process
Within the genome of an organism, synonymous codons (triplets of nucleotides which result in the same amino acid) are found in unequal proportions. There are various potential causes for this codon bias. Several major sources are adapted into a mean-field, stochastic, evolutionary model, and their relative importances are compared. This proposed model also results in various other universal features of genomes such as the distribution of protein lengths.
Jay Cushing
Moonshine: The Monster under your theory
The 1998 Fields Medal was awarded to Richard Borcherds for his proof of what is known as the Moonshine conjecture. With this proof came the introduction of structures known as vertex operator algebras which have been extremely fruitful in string theory. This has also opened the doorway to a large series of mysterious and deep connections between number theory, finite group theory, and conformal field theory. In this talk we will take a brisk walk through many of the exciting features of Moonshine, particularly Monstruous Moonshine, keeping a close eye to the physical motivation.
Nikhil Tilak
Strain Engineering in 2D materials
Generating Strain in any crystal causes its electro-optic properties to change. 2D crystalline materials like Graphene, hexagonal Boron Nitride and MoS2 can survive significantly higher strains than 3D materials owing to their high mechanical strength. This enables us to engineer the electro-optic properties of these 2D materials simply by generating strain in them. Moreover, many of these 2D materials have been predicted to show a very strong Piezoelectric effect. This is particularly exciting because of the potential applications in self-powered electronic devices and sensors.
Elaad Applebaum
Sampling the Initial Mass Function for Cosmological Simulations
Cosmological simulations seek to recreate the process of galaxy formation and evolution as accurately as possible. As resolutions get higher, it becomes necessary to implement a more realistic prescription for star formation. With this motivation, I discuss the initial mass function, which describes the mass distribution of stars at the time of formation. I will consider proper sampling methods for this function, and prospects for implementing them into cosmological simulations. Pretty pictures of space guaranteed.
Gleb Kotoousov
Lattice systems and the Thirring Model
In this talk we will be having fun with 1 dimensional quantum systems, including the famous Heisenberg XXZ spin chain. We will see how the scaling limit of the spin chain results in the Thirring Model, a Quantum Field Theory of Dirac fermions . Along the way, we’ll touch on a number of key physics ideas such as Universality and Lorentz Invariance.
Jonathan Viereck
The Ricci Flow
The Ricci flow is a natural generalization of the heat equation to the geometry of manifolds. It is fundamentally related to the renormalizability of certain field theories called nonlinear sigma models. In the 1980's, the Ricci flow was studied in differential geometry as a tool to investigate the decomposition of three dimensional manifolds. These studies ultimately led to the proof of the Poincare conjecture. In this talk, we will look at solutions to the Ricci flow in two and three dimensions and what this means for physics.
Anthony Frachioni
Maintenance of mental health as a graduate student: addressing a silent epidemic
Mental health problems among the population of graduate students in science will be discussed, with a particular focus on depression and suicidal ideation. The speaker will present on the empirical prevalence of such issues, in combination with an overview of resources available local to Rutgers, practices of hygiene, and coping skills.
Raghav Kunnawalkam Elayavalli
Jetting through the primordial soup
Ever since RHIC announced the creation of the quark gluon plasma in relativistic heavy ion collisions, study of the strongly interacting, high temperature and high energy density has elucidated several key features of QCD. We at Rutgers are experts in creating a tomographical picture of the QGP by utilizing fully reconstructed objects called jets, that travel through the medium on its way to our detectors. In this talk, I will attempt to draw a state of the art qualitative (and quantitative to a degree) picture of what happens to a parton moving through this dense (colored) medium and our takeaways from measurements at the LHC.
Vaibhav Dwivedi
Dynamics of 1D Bosons in the presence of electric field- You know what I did last summer
We study the exact dynamics of 1D interacting Bose gas in the presence of a spatially uniform, time dependent Electric field. We begin by introducing and exactly solving the Lieb-Liniger model of 1D Bose gas, in the absence of any electric field and proceed to solve the time dependent Schrodinger's equation in the presence of a time dependent linear potential.
Ethan Cline
SeaQuest - Studying Sea Quark Asymmetry
I'll be going over the physics of the SeaQuest experiment, the Drell-Yan process, and how we use it to probe the quark distributions of the nucleus. There will also be discussion of general issues in nuclear structure including the EMC effect, the Gottfried Sum Rule, and quark flavor asymmetry.
Daniel Brennan
String Theory: What is it good for?
Despite what Edwin Starr might tell you, string theory is a very useful tool for physicists that has led (and probably will lead) to many new ways of thinking about quantum physics. For example the study of string theory has lead to the discovery of exotic quantum theories without a known Lagrangian description and has lead to the discovery of the AdS/CFT correspondence. In addition, string theory gives us a way to study strongly coupled quantum field theories, which may potentially lead insight into fundamental problems such as quark confinement.
Ethan Cline
You Would Be Forgiven for Assuming that We Understand the Proton
In 2010 Randolf Pohl measured the radius of the proton to be 4% smaller than the accepted CODATA radius with an unprecedented accuracy. This may not sound significant but the Proton Radius Puzzle is a high profile issue within the nuclear physics community. In this talk the Puzzle will be discussed and the Muon Proton Scattering Experiment’s place in attempting to resolve the Puzzle will be presented.
Conan Huang
Introduction to Markov Chain Monte Carlo
Markov chain Monte Carlo is arguably one of the most important algorithms and is extensively used in modern simulations and numerical methods. A brief overview of Markov chains and Monte Carlo will be introduced. More importantly, for modern graduate students not only could Markov chain Monte Carlo be useful, but the advent of pizza is also very important in physics.
Raghav Kunnawalkam Elayavalli
Physics of the Beam. "Scotty, beam us up!"
Beams have always been used by physicists to study many different aspects of nature. From your simple table top diffraction experiment to the largest operating experiment on the planet, we all use some form of either a beam to probe or scatter or annihilate objects. In this talk, I will focus more on the particle beams at CERN and particularly how they produce and maintain said stable beams for physics collisions. This procedure of generating a beam of highly focused particles from a canister of gas contains many different steps, some of which are a phenomenal feat of scientific ingenuity and engineering receiving the highest award for scientific research, the Nobel Prize in 1984. This has also led to remarkable public utility in many fields such as medicine and consumer electronics (on which you are all reading this abstract).
Colin Rylands
The Wonderful World of One Dimension (Plus Time)
Aniket Patra
On Exact Solutions of Novel Multistate Landau-Zener Problems
A multistate Landau-Zener (MLZ) Hamiltonian is used to model numerous non-equilibrium experiments involving cold atoms, quantum dots and quantum dot molecules. We recently showed that all the known MLZ problems either reduce to the 2 X 2 Landau Zener problem or belong to a family of mutually commuting Hamiltonians (that are polynomial in time). Based on this classication we identify previously unknown MLZ problems, explicitly obtain their solutions and discuss relevant experimental scenarios.
Daniel Brennan
Monopoley
One of the questions of fundamental physics is understanding the asymmetry between electric and magnetic fields: namely why is there electrically charged matter but no magnetically charged matter. The question of why there are no monopoles have baffled physicists for a very long time. The idea of these "particles" has been revisited at every theoretical revolution in the past century by people such as Dirac, 't Hooft, Polyakov, and many others. In this talk we will talk about the role of monopoles in modern physics and how they relate to cosmology, condensed matter, particle physics, and the role of confinement.
Vaibhav Dwivedi
Integral Systems and Quenching
Interacting systems in quantum physics are common place, but only few systems are integrable. In this talk we discuss mostly Lieb-Liniger system, which is integrable exactly using Bethe Anstaz. We will also then talk about quantum quenching a free bosonic system with Leib-Liniger Hamiltonian using the Yudson representation.
Long Yan Yung
The Interplay of Cosmic Reionization and Galaxy Formation
During its 13.8 billion-year-long evolution, our Universe has undergone many phases and phase transitions. Two of the most interesting events in cosmic history are the formation of the first galaxies and cosmic reionization. Galaxies are regarded as the fundamental entities of large-scale structures in the Universe, which their formation strongly dependent on the cosmic environment. On the other hand, these galaxies can also provide feedback effects that can alter the cosmic environment, hence indirectly shape future formation activities. Galaxy formation is inseparable from the evolution of the cosmic environment. Therefore, understanding the interplay of the two can help us better understand the overall cosmic evolution history.
Wen-Sen Lu
Josephson Junctions
Given its scalability and compatibility to current silicon industry, superconducting qubit has become an ideal candidate for realizing quantum circuits. In order to understand and achieve reliable quantum operation, I would like to focus on the fundamental building blocks of superconducting circuits, which is the Josephson junction. In this talk, I will introduce the properties of Josephson junctions elements, the experimental approaches to fabricate and characterize Josephson junctions, and investigate the possible application of superconducting qubits.
Jesus Rives
Superresolution Microscopy
Since their invention in the 17th century microscopes were thought to have enjoyed unlimited improvement, but 1873 Ernst Abbe developed the diffraction limit. Superresolution microscopy are techniques that work around the diffraction limit to improve resolution more than 10 fold with visible light and, in some cases, promise unlimited resolution. Unlike their high resolution, diffraction limited cousins such as X-Ray microscopy, these methods allow for greater range of samples and are paving the way for readily accessible widefield, live imaging.
Catie Raney
Gravitational Lensing by Galaxy Clusters
Galaxy clusters are the largest gravitationally bound structures in the Universe. Consisting of thousands of galaxies, hot intra-cluster gas, and dark matter, they are also the most massive structures known. Since they are so dense, they cause light from background sources to be bent around them, a phenomenon known as gravitational lensing. The bending both distorts and magnifies these distant sources, allowing them to be more easily detected and studied, which has earned cluster lenses the name 'cosmic telescopes'. In this talk I will give background information on gravitational lensing and discuss techniques in how we model these complex mass distributions.
Parmesh Pasnoori
What's inside a black hole?
Black holes are mysterious objects which came out of general relativity (GR). They taught us a lot about GR in the past and now they are playing a key role in understanding quantum gravity. They are also being used as tools in understanding highly coupled gauge theories, certain condensed matter systems and the list goes on. But what is inside a black hole is still a mystery.
I will give a qualitative explanation of how a black hole curves space-time and then I will briefly go over hawking radiation and the puzzles which come out of it. I will then give a summary of some important papers which try to solve these puzzles thereby revealing a plausible structure of the black hole. In the end I will talk about the current research relating AdS/CFTto black hole interior.
Anothy Frachioni
"I'm going to talk about Tin"
I present an overview of a study of the phase and interface properties of pure Sn by molecular dynamics, and describe the application of non-Boltzmann simulation to this end. Several orientations of both alpha- and beta-Sn crystals have been simulated in direct coexistence with liquid at constant pressure, with potentials provided by the Modified Embedded Atom Method (MEAM). Simulations are carried out for pressures ranging from zero to 10 GPa and temperatures from 200 K to 1000 K. A complete phase diagram for Sn is mapped on this interval, and comparison is made between competing sets of MEAM parameters with regard to phase stability.
Abhijith Gandrakota
Gravity from Entanglement
Entanglement Entropy in the recent year has been a powerful tool to provide with new insights in various areas of Physics. One class of such attempts was to provide us insights about gravity in the context of gravity. Inspired by the approach taken by Ted Jacobson in deriving the Einstein's equations starting from Thermodynamical arguments. We are exploring such a possibility starting from the Quantum informatic arguments. We take condition of positivity of relative entropy arising from Unitarity quantum mechanics and imposing these arguments in the context of holography with the help of Ryu-Takayanagi formulation. Imposing these relative entropy conditions on the Quantum Field theories with Holographic dual, we explore constrains imposed on the gravitational theories allowed in the holographic bulk.
Raghav Kunnawalkam Elayavalli
Heavy Ions at the LHC: When protons aren't big enough
Heavy Ion physics has a rich history of studies carried out at Berkeley, SPS, RHIC and now at CERN where nuclear physicists are pushing the boundaries of our understanding of the strong force. At such high energies, heavy ion collisions create a viscus, high temperature and strong force mediated fluid called the quark gluon plasma (QGP). Here are Rutgers, we are involved with the CMS detector and study the transport and topological properties of the QGP. I’ll give a brief introduction to the field, our motivation and what we have learnt so far from the first run followed by an outlook to the future in this experiment driven field.
Chris Monahan
How to Build a Proton: Quarks, Gluons and Supercomputers
The Standard Model of Particle Physics is an enormously successful theory. It is also an enormously rich and complicated theory. Much of that richness and complexity stems from quantum chromodynamics (QCD), the gauge theory of the strong interaction. QCD describes how quarks interact via gluons to form protons, neutrons and, indeed, most of the visible matter in the Universe. Unfortunately QCD cannot be solved analytically (at least, not yet), because it is inherently nonperturbative and confining. In other words, we can never observe individual quarks, only their bound states, such as protons and neutrons. The only method we have for a rigorous understanding of QCD is lattice QCD, in which we discretise spacetime and study the properties of QCD statistically, usually on supercomputers. I will introduce lattice QCD, discuss some of its successes and challenges and, of course, how to build a proton.
Daniel Brennan
An Introduction to the Standard Model
The Standard Model describes the matter content and interactions of the most fundamental particles of nature. It is one of the most successful theories in the history of physics in both prediction and experimental verification. However, there are many problems with the Standard Model, such as lack of gravity, description of dark matter, and matter/anti-matter asymmetry. In this talk we will describe some of these issues and some of their proposed resolutions.
Jasen Scaramazza
Random matrix theory: The greatest theory?
In the mid-twentieth century, physicists made the surprising discovery that square arrays of completely random numbers can be useful for characterizing Hamiltonians of real quantum systems. A cornerstone of random matrix theory is the nearest neighbor level spacing distribution: i.e. the histogram of spacings between consecutive eigenvalues. For typical random matrix ensembles and generic quantum systems, eigenvalues exhibit repulsive correlations. For special classes of physical models, however, the eigenvalues lose this repulsion and do not see each other at all. These systems are called integrable and my research has investigated the level statistics of ensembles of integrable matrices. Come see the results!
Jesus Rives
Super-resolution: A Brief Overview
Super-resolution techniques are a means for us to go beyond the Abbe diffraction limit without the need for potentially harmful elections or high energy photons. These techniques, along with clever experimental methods, have allowed us to better analyze biological specimen without killing them or freezing them, and to overcome issues common and advance microscopy techniques bring to live biological studies. This talk will motivate the need for super-resolution, give an overview of the two types, 'true' and 'functional,' and briefly discuss how compressed sensing - a sparse signal analysis method - and super-resolution work together to allow for analysis of more complex systems.
Daniel Brennan
Introduction to Instantons
Instantons are non-perturbative solutions to the classical equations of motion which have non-trivial topology and are relevant to quantum phenomena. In standard quantum mechanics, they primarily determine tunneling and decay rates. However in quantum field theory, they also contribute to a class of operators which break chiral symmetry and can lead to baryon decay. This talk will give an introduction to these non-perturbative solutions and how they lead to these unexpected quantum effects.
Juho Lee
LDA+DMFT implementation on H2 molecule
Dynamical Mean Field Theory (DMFT) is a powerful method to deal with strongly correlated materials where quasi-particle approach used in band structure calculation completely fails. In order to perform a realistic calculation, DMFT is combined with local density approximation (LDA+DMFT) and it is widely used in solids to predict properties of correlated systems. Here one of the simplest strongly correlated systems, the hydrogen molecule H2, is used as a testbed to develop a parameter-free LDA+DMFT framework.
John Wu
An introduction to galaxy clusters
Galaxy clusters are the most massive virialized structures in the universe. The evolution of cluster galaxies is highly dependent on the physics of their environment. I will give examples of how neutral hydrogen is dissipated in clusters and how such mechanisms can quench star formation.
John Bonini
High Throughput Density Functional Theory Calculations for Predicting New Ferroelectrics
A major goal of materials science is the discovery and design of new functional materials. Historically this process consisted of synthesis and experimental characterization of candidate materials, many of which would then be found to be neither interesting nor useful. First principles techniques allow for the structure and properties of candidate materials to be predicted before synthesis, providing valuable input for experimentalists. In this work first principles methods are used to explore candidate ferroelectrics in the LiGaGe structure type.
Raghav Kunnawalkam Elayavalli
A First look at Heavy Ion Collisions
Relativistic heavy ion collisions were first conceptualized by Fermi and Landau independently as a study of the bulk properties of nuclear matter. This was a tool to explore multi-particle productions/interactions, hadron gas systems, thermalized equilibrium and many such novel concepts. From the early 1-2GeV(Giga electron volt) per nucleon at Berkeley and Dubna to the current 200 GeV/nucleon at RHIC, Brookhaven National Lab and 2.76 TeV (tera electron volt)/nucleon at the LHC, we have uncovered many interesting phenomenon. The formation of strongly coupled medium (often called as the quark gluon plasma) is one of the main discoveries and I will focus my talk on the studying its properties. We will start with a conceptualized study of the theory/intuition behind the formation of such a medium and study some of its properties with experimental probes.
Savvas Kyriacou
Stealth Super Symmetry at 13 TeV Ideas and Tools
The LHC (Large Hadron Collider) revealed the existence of a Higgs-like particle providing the missing piece of the Standard Model. With the forthcoming restart of the collider at an ever-higher center of mass energy, techniques are being developed to face the new run challenges and to provide insight to what lies beyond the current understanding. Existing tools and ideas for a Stealth Supersymmetry search at the CMS (Compact Muon Solenoid) Experiment, will be presented at this talk, regarding boosted topologies involving photons and jets in the final state.
Daniel Brennan
Scalar Dark Matter from Grand Unified Theories
The Standard Model is one of the greatest achievements in physics of the past 50 years, being touted by many as the most successful theory of nature. It precisely describes many observed phenomena, including both electromagnetism and the interactions of nuclear particles; but it is not complete. One of the largest flaws of the standard model is derived from a collection of cosmological observations which points to the existence of a new type of matter which is not described standard model. While many dark matter candidates have been proposed with varying degrees of success, there is still no single theory of dark matter which has been universally accepted. In this talk, a new dark matter candidate will be proposed originating from the Higgs sector of grand unified theories after symmetry breaking at the grand unification scale.
Qiang Han
Modelling strongly correlated electron systems from the DMFT viewpoint
The DMFT (dynamic mean field theory) method, first introduced to study the metal insulator transition (MIT) behind the Hubbard model in infinite spatial dimensions, has been merged with the traditional density function theory (DFT), which is capable of capturing the correlation effect missed by DFT. In this talk, the DMFT method is discussed at some details, followed with a discussion on MIT. Next we introduce a formalism based on effective action to combine DFT and DMFT and use it to study the alpha-gamma transition in elementary cerium.
Ian Laflotte
Heavy Flavor Tagged Jets In Heavy Ion Collisions at CMS
Quark-gluon plasma (QGP) can be produced reliably for study in the laboratory using ultra-relativistic heavy ion collisions. These collisions are achieved by using the Large Hadron Collider (LHC), and then recorded at the Compact Muon Solenoid (CMS) Experiment. Events known as jets are readily observed and used as probes to deduce properties of the QGP medium. Jet shapes and momenta are expected to be altered by the medium, as well as their production cross sections. Using specific tagging algorithms, one can identify the flavor of the parton which started the jet. Thus modifications due to the presence of a hot and dense medium can be parameterized as a function of jet-flavor. In this talk, results at CMS involving heavy flavored jets are summarized and discussed.
Kartheik Iyer
What's 3d about 2d CFT?
Conformal field theories are related to models of statistical physics at critical point. These theories are epsecially interesting in two dimensions because the group of local conformal transformations is just given by holomorphic functions. Wess-Zumino-Witten models are a class of CFTs whose solutions are characterised by affine Kac-Moody algebras. There is a close connection between Chern-Simons theory on a 3-manifold with a boundary, and a Wess-Zumino-Witten conformal field theory on that boundary. This connection is made explicit by identifying a basis of the Hilbert space of the CS theory with the set of characters of the corresponding WZW theory. I attempt to make this correspondence more explicit, and provide illustrative examples.
David Walter
Reducing Ambiguities in Spectroscopic Factors and the 86Kr(d,p) reaction at 35MeV/u
We can experimentally probe nuclear structure with single nucleon transfer reactions, such as (d,p), and characterize its shape with parameters like the spectroscopic factor and asymptotic normalization coefficients (ANC). Determining spectroscopic information for neutron rich nuclei near the N=50 shell closure is important in both astrophysics and nuclear physics for understanding r-process solar abundances and nuclear structure far from stability. Mukhamedzhanov and Nunes have proposed a new method of measuring a single particle transfer reaction at both low (peripheral reaction) and higher (less-peripheral) energies that should enable spectroscopic factors to be more reliably deduced, with uncertainties dominated by the experimental cross-section measurement rather than the shape of the single-particle nucleon-target interaction.
Colin Rylands
Bose-Einstein Condensates, Optical Lattices, and Integrability
Using gases of ultra cold atoms and counter propagating lasers it is possible to directly realise many theoretical models developed in the context of solid state physics. The amount of control and precision afforded by these experiments puts new emphasis on theoretical descriptions that can be solved exactly. In this talk I will describe these experiments, what an exactly solvable model is and one way to exactly solve an exactly solvable model.
Willow Kion-Crosby
Scaling Theory & Network Diffusion in Biological Systems
Transport on networks is an important function for various biological systems. Having a full theory of transport would be highly valuable, but this task has proven to be a challenge. One method that was introduced by Gallos et al to help develop these ideas further was the concept that renormalization can be applied to bionetworks.
John Wu
Understanding Spectral Energy Distributions and the Physics Behind Them
Astronomers love showing plots of any kind. One, called the spectral energy distribution (SED), is particularly useful for characterizing the radiative processes in astrophysical systems. I will present the SED of a prototypical star forming galaxy and explain the wide range of physics that give rise to its features.