
Home page of
Daniel Friedan


Position: 
Faculty 
Research group: 
High Energy Theory 
Email address: 
friedan AT physics.rutgers.edu 
Telephone: 
(732) 4455500 x3737
secretary: (732) 4455500 x2783, fax: (732) 4454993 
Office: 
Serin E366 
Mailing address: 
Daniel Friedan
Department of Physics and Astronomy
Rutgers, The State University of New Jersey
126 Frelinghuysen Road
Piscataway, NJ 088548019 USA

Teaching
Fall 2013: General Physics 203 recitations
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 twodimensional
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 LBL11517 (1980) and reprinted 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.
The theory I am currently working on 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).
The most recent steps were mathematical explorations of the YangMills
flow, presented in a paper: A
loop of SU(2) gauge fields stable under the YangMills flow (2010).
I am also trying to understand the basic properties of
nearcritical quantum circuits. These are
onedimensional 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 largescale 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.
More papers in this area:
Papers
Unpublished manuscripts:
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 LBL11517 (1980) (scanned)

Nonlinear Models in 2+&epsilon
Dimensions,
U.C. Berkeley doctoral thesis reprinted as
Annals of Physics 163 (1985) 318.

Some
Nonabelian Toy Models in the Large N Limit,
Communications in Mathematical Physics 78 (1981) 353362.

A Proof of the
NielsenNinomiya Theorem,
Communications in Mathematical Physics 85 (1982) 481490.

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 1017, 1983, Publications of the Mathematical Sciences Research Institute #3, SpringerVerlag (1984) (scanned).

Supersymmetric Derivation of the AtiyahSinger Index and the
Chiral Anomaly, Nuclear Physics B235 (1984) 395.

Covariant Methods in Superstring Theory, preprint EFI8509
(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,
Physics Letters B151 (1985) 37.

Random walks in twodimensional random random environments with
constrained drift forces, Physical Review A31, 6 (1985) 38413845.

Notes on String Theory and Two Dimensional Conformal Field
Theory, preprint EFI8599 (scanned, 2up),
(cropped to 1up),
published in the Proceedings of the Workshop on Unified String Theories, Santa
Barbara, July 29  August 16, 1985, p. 162.

Strings in Background Fields,
Nuclear Physics B262 (1985) 593.

Covariant Quantization of Superstrings,
Physics Letters B160 (1985) 55.

On TwoDimensional Conformal Invariance And The Field Theory Of String,
Physics Letters B162 (1985) 102.

Conformal invariance, supersymmetry and string theory,
Nuclear Physics B271 (1986) 93.

String field theory,
Nuclear Physics B271 (1986) 540.

All free string theories are theories of forms,
Nuclear Physics B274 (1986) 71.

Covariant quantization of supersymmetric string theories: The spinor
field of the RamondNeveuSchwarz model,
Nuclear Physics B278 (1986) 577.

Details of
the NonUnitarity Proof for Highest Weight Representations of the
Virasoro Algebra,
Communications in Mathematical Physics 107 (1986) 535542.

Determinant Formulae and Unitarity
for the N=2 Superconformal Algebras in TwoDimensions or Exact Results
on String Compactification,
Physics Letters B172 (1986) 316.

The integrable analytic geometry of quantum string,
Physics Letters B175 (1986) 287.

The Analytic Geometry of Two Dimensional Conformal Field Theory,
Nuclear Physics B281 (1987) 509.

A New Formulation of String Theory,
Physica Scripta T15 (1987) 7888.

The Conformal Field Theory of Orbifolds,
Nuclear Physics B282 (1987) 13.

Super Characters and Chiral Asymmetry in Superconformal Field Theory,
Nuclear Physics B296 (1988) 779.

Phenomenology and Conformal Field Theory or Can String Theory
Predict the Weak Mixing Angle,
Nuclear Physics B299 (1988) 613.

cTheorem and Spectral Representation,
Nuclear Physics B352 (1991) 616.
Copies of more recent papers:

A tentative theory of large distance physics,
JHEP 0310:063 (2003).
 Boundary Entropy of
Onedimensional Quantum Systems at Low Temperature,
Physical Review Letters 93 (2004) 030402.
 Entropy flow in
nearcritical quantum circuits, arXiv:condmat/0505084.
 Entropy flow
through nearcritical quantum junctions, arXiv:condmat/0505085.

Infrared properties of boundaries in onedimensional quantum systems,
Journal of Statistical Mechanics P03014 (2006).

Supersymmetric 1+1D boundary field theory,
Journal of Physics A: Mathematical and Theoretical
42 (2009) 304015.

General properties of the boundary renormalization group flow for
supersymmetric systems in 1+1 dimensions,
Advances in Theoretical and Mathematical Physics
13 no. 6 (2009) 0810.0611.

Gradient formula for the beta function of 2D quantum field theory,
Journal of Physics A: Mathematical and Theoretical 43 (2010) 215401.

A loop of SU(2) gauge fields stable under the YangMills
flow,
Surveys in Differential Geometry, Vol. 15 (2010),
Perspectives in mathematics and physics: Essays dedicated to Isadore
Singer's 85th birthday,
edited by
Tomasz Mrowka
and ShingTung Yau,
Publisher: International Press of Boston.
 Cargese 2002
transparencies
 Wigner Symposium
2003 transparencies
 Talks on rg flows, the Ricci flow, and the YangMills flow:
 Introduction to
the Renormalization Group Flow (Banff, April
15, 2008)
 A
conjecture on the Ricci flow (Banff, April 16, 2008)

Supersymmetric 1+1d boundary field theory (Conference in
Memory of Alexei
Zamolodchikov, Moscow, June 22, 2008)
 Properties
of the boundary renormalization group flow (Strasbourg,
September 12, 2008)
 Quantum
field theory and the Ricci flow (Reykjavik,
October 20, 2008)
 Gradient
property of the boundary rg flow for supersymmetric 1+1d
quantum field theories (Munich,
November 24, 2008)
 Introduction to the 2d Nonlinear Model
and the Renormalization Group Flow (Stony Brook,
January 22, 2009)
 Gradient
property of the boundary rg flow for supersymmetric 1+1d
quantum field theories (Edinburgh, January 28, 2009)
 Preliminary
evidence for a stable 2sphere in the
YangMills flow for SU(3) gauge fields on S4 (Pisa,
June 24, 2009)
 Pisa
talk: Addendum July 6, 2009
 A loop of SU(2)
gauge fields on S^4 stable under the YangMills flow (MIT, November 3, 2009)
Links to other people's work
Other links
Please send any comments on this page to friedan AT physics.rutgers.edu.
Revised August 26, 2010