Home page of Daniel Friedan

Teaching / Research / Papers and talks / Links

Teaching

Physics 616 Quantum Field Theory I

Research

I work on two projects: one concerning the fundamental laws of physics, the other concerning certain condensed matter systems that might eventually be useful in quantum computers. Both projects use the technology of two-dimensional quantum field theory.

I have formulated and am investigating a physical mechanism that at least formally determines the background spacetime for string theory. The hope is that this mechanism will actually produce the combination of General Relativity and the Standard Model of particle physics that has so accurately described physics across an astonishingly wide range of distance scales.

My efforts in this direction started with my doctoral thesis, first presented in a talk at the 1979 Nuffield Workshop on Quantum Gravity, then published as a letter, Physical Review Letters 45 (1980) 1057, then published in full as LBL Report LBL-11517 (1980) and as Annals of Physics 163 (1985) 318.  Other early work was presented in 1982 lectures at Les Houches, and in 1984 lectures at Aspen and at the Santa Fe APS Meeting.

My work of recent years was presented in a paper in 2002:  A tentative theory of large distance physics.  A summary was presented at Cargese 2002. A short sketch was given at the 2003 Wigner Symposium (transparencies).

I am also trying to understand the basic properties of near-critical quantum circuits. These are one-dimensional condensed matter systems near a low temperature critical point. I have argued that such systems are the only physical systems that are practical for asymptotically large-scale quantum computers.

These systems behave in universal ways which are described by 1+1 dimensional quantum field theories. Universal physical properties of these systems can be discovered by investigating the general structures of 1+1 dimensional quantum field theories.

My first efforts in this direction were my doctoral thesis (see above) and Physical Review Letters 52 (1984) 1575, and Physics Letters B151 (1985) 37.

My most recent papers on 1d quantum systems are:

• On the Boundary Entropy of One-dimensional Quantum Systems at Low Temperature
• Entropy flow in near-critical quantum circuits
• Entropy flow through near-critical quantum junctions

Papers

• Publications listed in the SPIRES Database

Unpublished manuscripts:

• Geometric Models for Critical Systems in 2+&epsilon Dimensions, 1979 manuscript, prepared for the directors of the Nuffield Workshop on Quantum Gravity.
• The Space of Conformal Boundary Conditions for the c=1 Gaussian model, 1999 note, circulated privately.
• The Space of Conformal Boundary Conditions for the c=1 Gaussian model (more), 2003 note, circulated privately.
• On general properties of supersymmetric boundary renormalization group flows, 2006 preliminary draft of a paper with Anatoly Konechny proving a gradient formula for the beta-function of supersymmetric 1+1 dimensional boundary quantum field theory.

Copies of some older papers:

• Nonlinear Models in 2+&epsilon Dimensions, Physical Review Letters 45 (1980) 1057.
• Nonlinear Models in 2+&epsilon Dimensions, U.C. Berkeley doctoral thesis, LBL Report LBL-11517 (1980) (scanned), reprinted as Annals of Physics 163 (1985) 318.
• Some Nonabelian Toy Models in the Large N Limit, Communications in Mathematical Physics 78 (1981) 353-362.
• A Proof of the Nielsen-Ninomiya Theorem, Communications in Mathematical Physics 85 (1982) 481-490.
• Introduction to Polyakov's String Theory, Les Houches lectures (1982) (scanned).
• Conformal Invariance, Unitarity and Two Dimensional Critical Exponents, published in Vertex Operators in Mathematics and Physics -- Proceedings of a Conference November 10-17, 1983, Publications of the Mathematical Sciences Research Institute #3, Springer-Verlag (1984) (scanned).
• Supersymmetric Derivation of the Atiyah-Singer Index and the Chiral Anomaly, Nuclear Physics B235 (1984) 395 (scanned).
• Covariant Methods in Superstring Theory, preprint EFI-85-09 (scanned), published in Proceedings of the Annual Meeting of the APS Division of Particles and Fields, Santa Fe, Oct 31 - Nov 3, 1984, p. 437.
• Conformal Invariance, Unitarity, and Critical Exponents in Two Dimensions, Physical Review Letters 52 (1984) 1575.
• Superconformal Invariance in Two Dimensions and the Tricritical Ising Model, preprint EFI-84-35 (scanned), published in Physics Letters B151 (1985) 37.
• Random walks in two-dimensional random random environments with constrained drift forces, Physical Review A31, 6 (1985) 3841-3845.
• Notes on String Theory and Two Dimensional Conformal Field Theory, preprint EFI-85-99 (scanned), published in the Proceedings of the Workshop on Unified String Theories, Santa Barbara, July 29 - August 16, 1985, p. 162.
• Details of the Non-Unitarity Proof for Highest Weight Representations of the Virasoro Algebra, Communications in Mathematical Physics 107 (1986) 535-542.
• Determinant Formulae and Unitarity for the N=2 Superconformal Algebras in Two-Dimensions or Exact Results on String Compactification, preprint EFI-86-14 (scanned), published in Physics Letters B172 (1986) 316.
• The Analytic Geometry of Two Dimensional Conformal Field Theory, preprint EFI-86-18A (scanned), published in Nuclear Physics B281 (1987) 509.

Copies of more recent papers:

• A tentative theory of large distance physics, JHEP 0310:063 (2003).
• Boundary Entropy of One-dimensional Quantum Systems at Low Temperature, Physical Review Letters 93 (2004) 030402.
• Entropy flow in near-critical quantum circuits, arXiv:cond-mat/0505084.
• Entropy flow through near-critical quantum junctions, arXiv:cond-mat/0505085.

Talks:

• Cargese 2002 transparencies
• Wigner Symposium 2003 transparencies
  

Links to other people's work

• Cosmic View: The Universe in 40 Jumps   by Kees Boeke
       (a book for children published in 1957)
  

Other links

• physics webmail
• Rutgers webmail

Revised March 22, 2008