127 research outputs found
Higher Equations of Motion in Boundary Liouville Field Theory
In addition to the ordinary bulk higher equations of motion in the boundary
version of the Liouville conformal field theory, an infinite set of relations
containing the boundary operators is found. These equations are in one-to-one
correspondence with the singular representations of the Virasoro algebra. We
comment on the possible applications in the context of minimal boundary
Liouville gravity.Comment: 18 page
Search for Axionlike and Scalar Particles with the NA64 Experiment
We carried out a model-independent search for light scalar (s) and
pseudoscalar axionlike (a) particles that couple to two photons by using the
high-energy CERN SPS H4 electron beam. The new particles, if they exist, could
be produced through the Primakoff effect in interactions of hard bremsstrahlung
photons generated by 100 GeV electrons in the NA64 active dump with virtual
photons provided by the nuclei of the dump. The a(s) would penetrate the
downstream HCAL module, serving as shielding, and would be observed either
through their decay in the rest of the HCAL detector or
as events with large missing energy if the a(s) decays downstream of the HCAL.
This method allows for the probing the a(s) parameter space, including those
from generic axion models, inaccessible to previous experiments. No evidence of
such processes has been found from the analysis of the data corresponding to
electrons on target allowing to set new limits on the
-coupling strength for a(s) masses below 55 MeV.Comment: This publication is dedicated to the memory of our colleague Danila
Tlisov. 7 pages, 5 figures, revised version accepted for publication in Phys.
Rev. Let
Affine sl(N) conformal blocks from N=2 SU(N) gauge theories
Recently Alday and Tachikawa proposed a relation between conformal blocks in
a two-dimensional theory with affine sl(2) symmetry and instanton partition
functions in four-dimensional conformal N=2 SU(2) quiver gauge theories in the
presence of a certain surface operator. In this paper we extend this proposal
to a relation between conformal blocks in theories with affine sl(N) symmetry
and instanton partition functions in conformal N=2 SU(N) quiver gauge theories
in the presence of a surface operator. We also discuss the extension to
non-conformal N=2 SU(N) theories.Comment: 40 pages. v2: minor changes and clarification
Strings on Semisymmetric Superspaces
Several string backgrounds which arise in the AdS/CFT correspondence are
described by integrable sigma-models. Their target space is always a Z(4)
supercoset (a semi-symmetric superspace). Here we list all semi-symmetric
cosets which have zero beta function and central charge c<=26 at one loop in
perturbation theory.Comment: 25 pages, 1 figur
Fast Control Systems: Nonlinear Approach
International audienceThis chapter treats the problem of fast control design for nonlinear systems. First, we discusses the question: which nonlinear system can be called fast? Next, we develop some tools for analysis and design of such control systems. The method generalized homogeneity is mainly utilized for these purposes. Finally, we survey possible research directions of the fast control systems
A slice of AdS_5 as the large N limit of Seiberg duality
A slice of AdS_5 is used to provide a 5D gravitational description of 4D
strongly-coupled Seiberg dual gauge theories. An (electric) SU(N) gauge theory
in the conformal window at large N is described by the 5D bulk, while its
weakly coupled (magnetic) dual is confined to the IR brane. This framework can
be used to construct an N = 1 MSSM on the IR brane, reminiscent of the original
Randall-Sundrum model. In addition, we use our framework to study
strongly-coupled scenarios of supersymmetry breaking mediated by gauge forces.
This leads to a unified scenario that connects the extra-ordinary gauge
mediation limit to the gaugino mediation limit in warped space.Comment: 47 Pages, axodraw4j.st
Holographic three-point functions of semiclassical states
We calculate the holographic three-point functions in N = 4 super-Yang-Mills
theory in the case when two of the operators are semiclassical and one is dual
to a supergravity mode. We further discuss the transition to the regime when
all three operators are semiclassical.Comment: 17 pages, 3 figures; v2: refs. added, discussion in sec. 2.1
expanded; v3: misprint in (2.28) corrected, published versio
On the classical equivalence of monodromy matrices in squashed sigma model
We proceed to study the hybrid integrable structure in two-dimensional
non-linear sigma models with target space three-dimensional squashed spheres. A
quantum affine algebra and a pair of Yangian algebras are realized in the sigma
models and, according to them, there are two descriptions to describe the
classical dynamics 1) the trigonometric description and 2) the rational
description, respectively. For every description, a Lax pair is constructed and
the associated monodromy matrix is also constructed. In this paper we show the
gauge-equivalence of the monodromy matrices in the trigonometric and rational
description under a certain relation between spectral parameters and the
rescalings of sl(2) generators.Comment: 32pages, 3figures, references added, introduction and discussion
sections revise
Finite-Temperature Fractional D2-Branes and the Deconfinement Transition in 2+1 Dimensions
The supergravity dual to N regular and M fractional D2-branes on the cone
over \mathbb{CP}^3 has a naked singularity in the infrared. One can resolve
this singularity and obtain a regular fractional D2-brane solution dual to a
confining 2+1 dimensional N = 1 supersymmetric field theory. The confining
vacuum of this theory is described by the solution of Cvetic, Gibbons, Lu and
Pope. In this paper, we explore the alternative possibility for resolving the
singularity - the creation of a regular horizon. The black-hole solution we
find corresponds to the deconfined phase of this dual gauge theory in three
dimensions. This solution is derived in perturbation theory in the number of
fractional branes. We argue that there is a first-order deconfinement
transition. Connections to Chern--Simons matter theories, the ABJM proposal and
fractional M2-branes are presented.Comment: v3: analytic solutions are expose
Instanton partition functions in N=2 SU(N) gauge theories with a general surface operator, and their W-algebra duals
We write down an explicit conjecture for the instanton partition functions in
4d N=2 SU(N) gauge theories in the presence of a certain type of surface
operator. These surface operators are classified by partitions of N, and for
each partition there is an associated partition function. For the partition N=N
we recover the Nekrasov formalism, and when N=1+...+1 we reproduce the result
of Feigin et. al. For the case N=1+(N-1) our expression is consistent with an
alternative formulation in terms of a restricted SU(N)xSU(N) instanton
partition function. When N=1+...+1+2 the partition functions can also be
obtained perturbatively from certain W-algebras known as quasi-superconformal
algebras, in agreement with a recent general proposal.Comment: 20 page
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