Kenneth Wilson in Moscow
I try to recreate the scientific atmosphere during Wilson's visits to Moscow in '60-s and '70-s
physics.hist-ph↗
arXiv subjects
A. M. Polyakov
Publications and source records attributed to A. M. Polyakov.
Infrared instability of the de Sitter space
We continue to investigate various instabilities of the fixed backgrounds related to the de Sitter space. It is shown that in many cases the in/in perturbation theory contains IR/UV mixing and thus is non-renormalizible. The application of this result to the global de Sitter space leads to the conclusion that even massive particles generate IR divergence and the huge back reaction. The expanding universe is also unstable but in a weaker sense. We further discuss, the strange features of the Gibbons-Hawking radiation and its relation to the above instabilities. .
hep-th↗
Decay of Vacuum Energy
This paper studies interacting massive particles on the de Sitter background. It is found that the vacuum acts as an inversely populated medium which is able to generate stimulated radiation. Without back reaction (not considered in this paper) this effect leads to the explosion. It is expected that the proposed "cosmic laser" mechanism depletes the curvature and may help to solve the cosmological constant problem.
hep-th↗
From Quarks to Strings
In this article, prepared for the book "The birth of string theory", I recall the sequence of ideas which led to non-critical strings and gauge/strings duality. I also comment on some promising future directions.
hep-th↗
De Sitter Space and Eternity
This paper explores infrared quantum effects in the de Sitter space. The notion of "eternal manifolds" is introduced and it is shown that in most cases the de Sitter space doesn't belong to this class. It is unstable under small perturbations which may cause a breakdown of the de Sitter symmetry. The de Sitter string sigma model is discussed. It is argued that the gauge theory at the complex coupling is dual to the matrix elements of vertex operators in the de Sitter space, taken between the Bunch - Davies vacuum and the "out" state without particles.The described infrared effects are likely to screen away the cosmological constant.
hep-th↗
Beyond Space-Time
These notes, based on the remarks made at the 23 Solvay Conference, collect several speculative ideas concerning gauge/ strings duality, de Sitter spaces, dimensionality and the cosmological constant.
hep-th↗
Supermagnets and Sigma models
We discuss new methods for non-compact sigma models with and without RR fluxes. The methods include reduction to one dimensional supermagnets, supercoset constructions and supertwistors. This work is a first step towards the solution of these models, which are important in several areas of physics. I dedicate it to the memory of Volodya Gribov.
hep-th↗
Confinement and Liberation
This is a review of topics which haunted me for the last 40 years, starting with spontaneous symmetry breaking and ending with gauge/string/space-time correspondence. While the first part of this article is mostly historical, the second contains some comments, opinions and conjectures which are new. This work is prepared for the volume " Fifty Years of the Yang- Mills Theory"
hep-th↗
Conformal Fixed Points of Unidentified Gauge Theories
In this article we discuss gauge/strings correspondence based on the non-critical strings. With this goal we present several remarkable sigma models with the AdS target spaces. The models have kappa symmetry and are completely integrable. The radius of the AdS space is fixed and thus they describe isolated fixed points of gauge theories in various dimensions
hep-th↗
AdS Dual of the Critical O(N) Vector Model
We suggest a general relation between theories of infinite number of higher-spin massless gauge fields in $AdS_{d+1}$ and large $N$ conformal theories in $d$ dimensions containing $N$-component vector fields. In particular, we propose that the singlet sector of the well-known critical 3-d O(N) model with the $(ϕ^a ϕ^a)^2$ interaction is dual, in the large $N$ limit, to the minimal bosonic theory in $AdS_4$ containing massless gauge fields of even spin.
hep-th↗
A semi-classical limit of the gauge/string correspondence
A world-sheet sigma model approach is applied to string theories dual to four-dimensional gauge theories, and semi-classical soliton solutions representing highly excited string states are identified which correspond to gauge theory operators with relatively small anomalous dimensions. The simplest class of such states are strings on the leading Regge trajectory, with large spin in AdS_5. These correspond to operators with many covariant derivatives, whose anomalous dimension grows logarithmically with the space-time spin. In the gauge theory, the logarithmic scaling violations are similar to those found in perturbation theory. Other examples of highly excited string states are also considered.
hep-th↗
Gauge Fields and Space-Time
In this article I attempt to collect some ideas,opinions and formulae which may be useful in solving the problem of gauge/ string / space-time correspondence This includes the validity of D-brane representation, counting of gauge-invariant words, relations between the null states and the Yang-Mills equations and the discussion of the strong coupling limit of the string sigma model. The article is based on the talk given at the "Odyssey 2001" conference.
hep-th↗
Loop dynamics and AdS/CFT correspondence
We consider the strong coupling limit of conformal gauge theories in 4 dimensions. The action of the loop operator on the minimal area in the AdS space is analyzed, and the Schwinger-Dyson equations of gauge theory are checked. The general approach to the loop dynamics developed here goes beyond the special case of conformal theories.
hep-th↗
String theory as a universal language
This article, based on the Klein lecture, contains some new results and new speculations on various topics. They include discussion of open strings in the AdS space, unusual features of D-branes, conformal gauge theories in higher dimensions. We also comment on the infrared screening of the cosmological constant and on the "brane worlds"
hep-th↗
Gauge Theory Correlators from Non-Critical String Theory
We suggest a means of obtaining certain Green's functions in 3+1-dimensional ${\cal N} = 4$ supersymmetric Yang-Mills theory with a large number of colors via non-critical string theory. The non-critical string theory is related to critical string theory in anti-deSitter background. We introduce a boundary of the anti-deSitter space analogous to a cut-off on the Liouville coordinate of the two-dimensional string theory. Correlation functions of operators in the gauge theory are related to the dependence of the supergravity action on the boundary conditions. From the quadratic terms in supergravity we read off the anomalous dimensions. For operators that couple to massless string states it has been established through absorption calculations that the anomalous dimensions vanish, and we rederive this result. The operators that couple to massive string states at level $n$ acquire anomalous dimensions that grow as $2\left (n g_{YM} \sqrt {2 N} )^{1/2}$ for large `t Hooft coupling. This is a new prediction about the strong coupling behavior of large $N$ SYM theory.
hep-th↗
Dynamics of (n, 1) Strings
An $(n, 1)$ string is a bound state of a D-string and $n$ fundamental strings. It may be described by a D-string with a world volume electric field turned on. As the electric field approaches its critical value, $n$ becomes large. We calculate the 4-point function for transverse oscillations of an $(n, 1)$ string, and the two-point function for massless closed strings scattering off an $(n, 1)$ string. In both cases we find a set of poles that becomes dense in the large $n$ limit. The effective tension that governs the spacing of these poles is the fundamental string tension divided by $1+(nλ)^2$, where $λ$ is the closed string coupling. We associate this effective tension with the open strings attached to the $(n, 1)$ string, thereby governing its dynamics. We also argue that the effective coupling strenth of these open strings is reduced by the electric field and approaches zero in the large $n$ limit.
hep-th↗
String theory and gravity
It is pointed out that string-loop effects may generate matter couplings for the dilaton allowing this scalar partner of the tensorial graviton to stay massless while contributing to macroscopic gravity in a way naturally compatible with existing experimental data. Under a certain assumption of universality of the dilaton coupling functions (possibly realized through a discrete symmetry such as S-duality), the cosmological evolution drives the dilaton towards values where it decouples from matter. At the present cosmological epoch, the coupling to matter of the dilaton should be very small, but non zero. This provides a new motivation for improving the experimental tests of Einstein's Equivalence Principle.
gr-qc↗
The String Dilaton and a Least Coupling Principle
It is pointed out that string-loop modifications of the low-energy matter couplings of the dilaton may provide a mechanism for fixing the vacuum expectation value of a massless dilaton in a way which is naturally compatible with existing experimental data. Under a certain assumption of universality of the dilaton coupling functions , the cosmological evolution of the graviton-dilaton-matter system is shown to drive the dilaton towards values where it decouples from matter (``Least Coupling Principle"). Quantitative estimates are given of the residual strength, at the present cosmological epoch, of the coupling to matter of the dilaton. The existence of a weakly coupled massless dilaton entails a large spectrum of small, but non-zero, observable deviations from general relativity. In particular, our results provide a new motivation for trying to improve by several orders of magnitude the various experimental tests of Einstein's Equivalence Principle (universality of free fall, constancy of the constants,\dots).
hep-th↗