34 research outputs found
Modularity and 4D-2D spectral equivalences for large-N gauge theories with adjoint matter
In recent work, we demonstrated that the confined-phase spectrum of
non-supersymmetric pure Yang-Mills theory coincides with the spectrum of the
chiral sector of a two-dimensional conformal field theory in the large-
limit. This was done within the tractable setting in which the gauge theory is
compactified on a three-sphere whose radius is small compared to the strong
length scale. In this paper, we generalize these observations by demonstrating
that similar results continue to hold even when massless adjoint matter fields
are introduced. These results hold for both thermal and -twisted
partition functions, and collectively suggest that the spectra of large-
confining gauge theories are organized by the symmetries of two-dimensional
conformal field theories.Comment: 51 pages, LaTeX, 3 figure
The Chern-Simons diffusion rate in strongly coupled N=4 SYM plasma in an external magnetic field
We calculate the Chern-Simons diffusion rate in a strongly coupled N=4 SUSY
Yang-Mills plasma in the presence of a constant external magnetic flux
via the holographic correspondence. Due to the strong interactions between the
charged fields and non-Abelian gauge fields, the external Abelian magnetic
field affects the thermal Yang-Mills dynamics and increases the diffusion rate,
regardless of its strength. We obtain the analytic results for the Chern-Simons
diffusion rate both in the weak and strong magnetic field limits. In the latter
limit, we show that the diffusion rate scales as and this can be
understood as a result of a dynamical dimensional reduction.Comment: 10 pages, 1 figure, typos corrected, comments adde
Conformal anomaly as a source of soft photons in heavy ion collisions
We introduce a novel photon production mechanism stemming from the conformal
anomaly of QCDxQED and the existence of strong (electro)magnetic fields in
heavy ion collisions. Using the hydrodynamical description of the bulk modes of
QCD plasma, we show that this mechanism leads to the photon production yield
that is comparable to the yield from conventional sources. This mechanism also
provides a significant positive contribution to the azimuthal anisotropy of
photons, , as well as to the radial "flow". We compare our results to the
data from the PHENIX Collaboration.Comment: 5 pages, 3 figures; version accepted to Phys. Rev. Let
A taxonomy of supply chain innovations
In this paper, a taxonomy of supply chain and logistics innovations was developed and presented. The taxonomy was based on an extensive literature survey of both theoretical research and case studies. The primary goals are to provide guidelines for choosing the most appropriate innovations for a company, and help companies in positioning themselves in the supply of chain innovations landscape. To this end, the three dimensions of supply chain innovations, namely the goals, supply chain attributes, and innovation attributes were identified and classified. The taxonomy allows for the efficient representation of critical supply chain innovations information, and serves the mentioned goals, which are fundamental to companies in a multitude of industries
Holographic Pomeron and the Schwinger Mechanism
We revisit the problem of dipole-dipole scattering via exchanges of soft
Pomerons in the context of holographic QCD. We show that a single closed string
exchange contribution to the eikonalized dipole-dipole scattering amplitude
yields a Regge behavior of the elastic amplitude; the corresponding slope and
intercept are different from previous results obtained by a variational
analysis of semi-classical surfaces. We provide a physical interpretation of
the semi-classical worldsheets driving the Regge behavior for (-t)>0 in terms
of worldsheet instantons. The latter describe the Schwinger mechanism for
string pair creation by an electric field, where the longitudinal electric
field E_L=\sigma_T tanh(\chi/2) at the origin of this non-perturbative
mechanism is induced by the relative rapidity {\chi} of the scattering dipoles.
Our analysis naturally explains the diffusion in the impact parameter space
encoded in the Pomeron exchange; in our picture, it is due to the Unruh
temperature of accelerated strings under the electric field. We also argue for
the existence of a "micro-fireball" in the middle of the transverse space due
to the soft Pomeron exchange, which may be at the origin of the thermal
character of multiparticle production in ep/pp collisions. After summing over
uncorrelated multi-Pomeron exchanges, we find that the total dipole-dipole
cross section obeys the Froissart unitarity bound.Comment: 17 pages, 4 figures, version 2: minor typos corrected, references
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Self-consistent crystalline condensate in chiral Gross-Neveu and Bogoliubov-de Gennes systems
We derive a new exact self-consistent crystalline condensate in the 1+1
dimensional chiral Gross-Neveu model. This also yields a new exact crystalline
solution for the one dimensional Bogoliubov-de Gennes equations and the
Eilenberger equation of semiclassical superconductivity. We show that the
functional gap equation can be reduced to a solvable nonlinear equation, and
discuss implications for the temperature-chemical potential phase diagram.Comment: 5 pages, 5 figures; v2 minor corrections, version for PR
A Gauge-Gravity Relation in the One-loop Effective Action
We identify an unusual new gauge-gravity relation: the one-loop effective
action for a massive spinor in 2n dimensional AdS space is expressed in terms
of precisely the same function [a certain multiple gamma function] as the
one-loop effective action for a massive charged scalar in 4n dimensions in a
maximally symmetric background electromagnetic field [one for which the
eigenvalues of F_{\mu\nu} are maximally degenerate, corresponding in 4
dimensions to a self-dual field, equivalently to a field of definite helicity],
subject to the identification F^2 \Lambda, where \Lambda is the
gravitational curvature. Since these effective actions generate the low energy
limit of all one-loop multi-leg graviton or gauge amplitudes, this implies a
nontrivial gauge-gravity relation at the non-perturbative level and at the
amplitude level.Comment: 6 page
Inhomogeneous Condensates in the Thermodynamics of the Chiral NJL_2 model
We analyze the thermodynamical properties, at finite density and nonzero
temperature, of the (1+1)-dimensional chiral Gross-Neveu model (the NJL_2
model), using the exact inhomogeneous (crystalline) condensate solutions to the
gap equation. The continuous chiral symmetry of the model plays a crucial role,
and the thermodynamics leads to a broken phase with a periodic spiral
condensate, the "chiral spiral", as a thermodynamically preferred limit of the
more general "twisted kink crystal" solution of the gap equation. This
situation should be contrasted with the Gross-Neveu model, which has a discrete
chiral symmetry, and for which the phase diagram has a crystalline phase with a
periodic kink crystal. We use a combination of analytic, numerical and
Ginzburg-Landau techniques to study various parts of the phase diagram.Comment: 28 pages, 13 figure
Gross-Neveu Models, Nonlinear Dirac Equations, Surfaces and Strings
Recent studies of the thermodynamic phase diagrams of the Gross-Neveu model
(GN2), and its chiral cousin, the NJL2 model, have shown that there are phases
with inhomogeneous crystalline condensates. These (static) condensates can be
found analytically because the relevant Hartree-Fock and gap equations can be
reduced to the nonlinear Schr\"odinger equation, whose deformations are
governed by the mKdV and AKNS integrable hierarchies, respectively. Recently,
Thies et al have shown that time-dependent Hartree-Fock solutions describing
baryon scattering in the massless GN2 model satisfy the Sinh-Gordon equation,
and can be mapped directly to classical string solutions in AdS3. Here we
propose a geometric perspective for this result, based on the generalized
Weierstrass spinor representation for the embedding of 2d surfaces into 3d
spaces, which explains why these well-known integrable systems underlie these
various Gross-Neveu gap equations, and why there should be a connection to
classical string theory solutions. This geometric viewpoint may be useful for
higher dimensional models, where the relevant integrable hierarchies include
the Davey-Stewartson and Novikov-Veselov systems.Comment: 27 pages, 1 figur
A Twisted Kink Crystal in the Chiral Gross-Neveu model
We present the detailed properties of a self-consistent crystalline chiral
condensate in the massless chiral Gross-Neveu model. We show that a suitable
ansatz for the Gorkov resolvent reduces the functional gap equation, for the
inhomogeneous condensate, to a nonlinear Schr\"odinger equation, which is
exactly soluble. The general crystalline solution includes as special cases all
previously known real and complex condensate solutions to the gap equation.
Furthermore, the associated Bogoliubov-de Gennes equation is also soluble with
this inhomogeneous chiral condensate, and the exact spectral properties are
derived. We find an all-orders expansion of the Ginzburg-Landau effective
Lagrangian and show how the gap equation is solved order-by-order.Comment: 28 pages, 13 figs; v2: new appendix on Eilenberger eq and refs;
version in PR