**Rutgers University Department of Physics and
Astronomy **

previous section - table of contents - next section

The Rutgers faculty in condensed matter theory have interests spanning many
areas including: new phases of quantum matter, highly-correlated electron
phenomena, such as high-temperature superconductivity, magnetism, quantum phase
transitions, oxide and heavy-fermion physics; physics at surfaces, including
dynamic phenomena and electronic and geometrical structure; quantum liquids
including superfluids and Bose Einstein condensates; equilibrium and
non-equilibrium statistical mechanics including the physics of glasses and
quantum dots; quantum computation, first principles calculations of electronic
and structural properties, including the applications of dynamical mean field
theory; quantum phase transitions and critical phenomena; semiconductor
physics; quantum statistical mechanics and field theory; thermodynamics,
transport and localization in disordered systems. At

**Professor (Emeritus) Elihu Abrahams**

My research activities are in theoretical condensed matter physics. My main interests concern the quantum-mechanical many-body problem in the presence of very strong particle-particle interactions. In this area, I have been using the techniques of quantum statistical mechanics and field theory to investigate the phase transitions and the transport and thermodynamic properties of a number of systems, including high-temperature superconductors, metals at the threshold of breakdown of Fermi-liquid behavior, strongly interacting disordered metals, localized spins in metals, and magnets with unusual spin correlations.

**Professor Natan Andrei**

I am interested in strongly correlated electron systems, particularly low dimensions where quantum fluctuations are enhanced and lead to new and often unexpected phenomena. Also, low dimensional many-body systems can be studied by powerful mathematical tools that yield non-perturbative results such as conformal field theory, bosonization and the Bethe-Ansatz. Most recently I have studied transport properties of quantum dots in and out of equilibrium, thermal conductivity in spin chains and ladders and the exact solutions of a variety of quantum impurity models.

**Professor Premala Chandra**

I am interested in a wide variety of subjects in condensed matter physics.
One area of my work concerns new forms of quantum equilibrium order - anything
from frustrated quantum spin systems to novel forms of quantum order in
strongly correlated electron systems. In my group we are trying to understand
the emergence of new types of behavior in non-equilibrium matter. One topic of
particular interest is glasses - where matter undergoes a transition to a state
which moves infinitely slowly, and which remembers its past. Together with Lev
Ioffe and Michael Gershenson, we are trying to design and fabricate a new class
of quantum qubit as the elementary element of tomorrows "quantum
computers". This requires a fine balance of good theory and contact with
real-world experiment. Another area of my work is in magneto-electrics, where
my group is working in collaboration with Experimentalist Sang Cheong and
collaborator Karin Rabe, to understand and develop new classes of hybrid
magneto-electric materials. I have recently moved to

**Professor Piers Coleman**

It is a very exciting time for condensed matter physics. This decade may well be like the late 1960s, a time when a convergence of particle physics and condensed matter physics led to the great revolution of understanding in classical criticality. Today, the same sort of sea-changes in our understanding of quantum matter are taking place, with the discovery of "quantum criticality" and quantum phase transitions. My research is concerned with the fundamentally new classes of collective condensed matter behavior that emerge in complex materials. Recently, I have been particularly interested in quantum phase transitions - which give rise to the formation of new classes of strange metals and nucleate new forms of quantum order, such as high temperature superconductors. I have active research activities in the subject of heavy fermion physics and also on strongly correlated mesoscopic systems such as quantum dots. I try to maintain a research portfolio that balances phenomenology and close contact with experiment, with the development of state-of-the-art mathematical tools for many body systems (such as the Slave boson). I'm constantly on the look out for talented young people who'd like to collaborate with this research.

**Professor Kristjan Haule**

We want to gain theoretical understanding of the behavior of real materials which fall under the rubric of strongly correlated electron systems. These are complex materials, with electrons occupying active 3d-, 4f- or 5f-orbitals. Recent advance in combining the well established electronic structure methods with the modern many body tools, such as Dynamical Mean Field theory and its cluster extensions, allows us for the first time, to carry out the first principle calculations for some complex correlated materials, such as the heavy fermions, doped Mott insulators, fullerens and many others. Together with the group of Gabriel Kotliar, we are trying to develop advanced methods and techniques that would allow us to explain and ultimately predict the properties of any correlated solid with a click of a mouse. The computer aided material design is now a promising research direction and the ability to predict physical properties of strongly correlated materials with many unusual properties makes the prospects for applications particularly exciting.

**Professor George K. Horton**

I have recently become interested in the subject of intrinsic localized
modes of vibration in perfect crystals, often called breathers. The possibility
that such excitations might exist was first broached by Sievers and Takeno in
Phys. Rev. Lett. 61, 970 (1988). They represent a strictly anharmonic effect.
Theoretically there seems to be no reason to believe that they do not exist and
they have been observed in special systems, i.e. micromechanical cantilever
arrays. The theoretical work has been reviewed by Sievers and Page in
"Dynamical Theory of Solids", edited by Horton and Maradudin,
Elsivier,

**Professor Lev Ioffe**

I am interested in many areas of theoretical condensed matter physics. Generally, I am interested in all aspects of strongly correlated and disordered electron systems but I am especially interested in the interplay between the disorder and a strong interaction. Currently, I am working on diverse problems related to quantum computation by solid state devices and on the physics of strongly interacting disordered electron systems. Specifically, I work on the formation of topologically protected states in Josephson junction arrays that can be used for quantum computation and on the microscopic sources of dephasing in the setups proposed for quantum computations that have been implemented in the laboratory. In the subfield of disordered systems I work on the glass formation in the materials with low density of the electrons where glassiness is due to the frustration induced by combination of the disorder and the long range Coulomb repulsion. Recently I started to work on a different set of problems related to the competition of superconductivity and localization, the physics of these problems (dominated by attraction instead of repulsion) is completely different but no less exciting. In my research I try to put the emphasis on the qualitative picture of the physical phenomena and so I prefer to use analytical tools of the modern condensed matter theory over the numerics that I resort to only when really unavoidable. The list of my recent publications and some recent papers on these subjects can be found at http://echidna.rutgers.edu/

**Professor Gabriel Kotliar**

We apply methods of quantum statistical mechanics quantum field theory and computational physics to treat fundamental problems in material science and condensed matter physics. My main interest in the area of disordered and strongly interacting electronic systems. Problems of current interest include the metal-insulator transition in doped semiconductors, the physical properties of transition metal oxides and the phenomena of high temperature superconductivity, the non linear optical properties of artificially fabricated semiconductor systems and the anomalous non equilibrium phenomena in glasses.

**Professor David Langreth**

Density functional theory of the type that led to the recent Nobel prize for Walter Kohn of UCSB provides the method of choice for the calculation of electronic structure of wide classes of dense condensed matter as well as isolated molecules. However, it has been singularly unsuccessful for sparse, soft, and much biological matter, which is equally abundant and important, because if fails to account for the long-range van der Waals or dispersion interactions. We have recently developed a generalization of density functional theory that shows great promise to extend its success to this wider class of important problems. We are in the process of testing our theory on a variety of layered systems, physisorption systems, van der Waals complexes. We have preliminary data for the important base pair stacking problem in DNA and RNA, which is probably a determinant of the pitch of the double helix, and we believe we will crack it. I continue to be interested in all the areas of my past, in particular the application of many-body techniques to problems in surface physics, and dynamical problems in highly correlated electron systems.

**Professor Paul Leath**

My recent research interests have been in the area of breakdown phenomena in disordered materials, e.g. brittle fracture, electrical breakdown, and the critical current in superconductors. Most recently, we have studied the crossover from tough to brittle fracture in heterogeneous and composite materials by both analytic and numerical simulation techniques. I have also explored the role of vortex line creation at defects and their subsequent motion on the behavior near the critical current in superconducting arrays of Josephson junctions. For many years, I have also been interested in phenomena near percolation threshold, where rigidity fails and the elastic constants go to zero even though the material is still connected. Also, I have plans to work again on phonons and spin wave excitations in disordered materials.

**Professor Karin M. Rabe**

The research in my group currently centers on the theoretical investigation of complex oxides. Chemical and structural complexity has proved to be an critical factor in producing a variety of fascinating properties of solids, including ferroelectricity, large piezoelectric and dielectric responses, and multiferroicity in metals and insulators, as well as quasicrystallinity and high-temperature superconductivity. Current research projects in my group include work on ferroelectric epitaxial thin films and superlattices and other artificially structured oxide materials, novel mechanisms for ferroelectricity in magnetic oxides, and development of multiscale methods for studying complex-oxide structural phase transitions at nonzero temperature. First-principles density-functional methods are used both directly and in the construction of first-principles effective Hamiltonians for theoretical prediction and analysis of properties of materials, both real and as-yet hypothetical, in bulk and thin film forms.

**Professor Andrei Ruckenstein**

My recent interests involve two general areas. The first is concerned with the many-body theory of strongly correlated systems, with emphasis on models of the high-Tc oxides, many-body effects, and the metal-insulator transition in doped semiconductors, the nature of itinerant magnetism, and the physics of heavy fermion systems. The second area of interest is that of coherent phenomena in quantum gases, such as spin-polarized excitons in germanium or spin-polarized atomic hydrogen.

**Professor ****David
Vanderbilt**

In recent decades, first-principles methods of computational
electronic-structure theory have provided extremely powerful tools for
predicting the electronic and structural properties of materials, using only
the atomic numbers of the atoms and some initial guesses at their coordinates
as input. My interests are in applying such methods to study the
atomic-scale properties of materials, especially ferroelectric and dielectric
oxides; bulk structural phase transitions; lattice contributions to dielectric and
piezoelectric activity; and properties of interfaces and superlattices. I also have an abiding interest in the
development of new theoretical approaches and computational algorithms that can
extend the reach and power of these first-principles methods. In particular,
I have made contributions to pseudopotential theory, the theory of electric
polarization and of insulators in finite electric fields, the theory of Wannier
functions and their applications, and the role of

**Professor Emil Yuzbashyan**

My main research interest is in strongly correlated and/or disordered systems. In particular, I work in the theory of superconductivity and superfluidity, including non-stationary superconductivity, cold fermions, and disordered superconductors. I am also interested in the physics of nanoscale and mesoscopic systems, such as quantum dots, quantum wires, and superconducting qubits.

previous section - table of contents - next section

Revised September, 2006