13 research outputs found
Real-time gauge/gravity duality: Prescription, Renormalization and Examples
We present a comprehensive analysis of the prescription we recently put
forward for the computation of real-time correlation functions using
gauge/gravity duality. The prescription is valid for any holographic
supergravity background and it naturally maps initial and final data in the
bulk to initial and final states or density matrices in the field theory. We
show in detail how the technique of holographic renormalization can be applied
in this setting and we provide numerous illustrative examples, including the
computation of time-ordered, Wightman and retarded 2-point functions in
Poincare and global coordinates, thermal correlators and higher-point
functions.Comment: 85 pages, 13 figures; v2: added comments and reference
Generalized Massive Gravity and Galilean Conformal Algebra in two dimensions
Galilean conformal algebra (GCA) in two dimensions arises as contraction of
two copies of the centrally extended Virasoro algebra ( with ). The central charges of
GCA can be expressed in term of Virasoro central charges. For finite and
non-zero GCA central charges, the Virasoro central charges must behave as
asymmetric form . We propose that, the bulk
description for 2d GCA with asymmetric central charges is given by general
massive gravity (GMG) in three dimensions. It can be seen that, if the
gravitational Chern-Simons coupling behaves as of order
O() or (), the central charges
of GMG have the above dependence. So, in non-relativistic scaling
limit , we calculated GCA parameters and finite
entropy in term of gravity parameters mass and angular momentum of GMG.Comment: 9 page
Towards a Non-Relativistic Holographic Superfluid
We explore the phase structure of a holographic toy model of superfluid
states in non-relativistic conformal field theories. At low background mass
density, we find a familiar second-order transition to a superfluid phase at
finite temperature. Increasing the chemical potential for the probe charge
density drives this transition strongly first order as the low-temperature
superfluid phase merges with a thermodynamically disfavored high-temperature
condensed phase. At high background mass density, the system reenters the
normal phase as the temperature is lowered further, hinting at a
zero-temperature quantum phase transition as the background density is varied.
Given the unusual thermodynamics of the background black hole, however, it
seems likely that the true ground state is another configuration altogether.Comment: 13+5 pages, late
More on Massive 3D Supergravity
Completing earlier work on three dimensional (3D) N=1 supergravity with
curvature-squared terms, we construct the general supergravity extension of
cosmological massive gravity theories. We expand about supersymmetric anti-de
Sitter vacua, finding the conditions for bulk unitarity and the critical points
in parameter space at which the spectrum changes. We discuss implications for
the dual conformal field theory.Comment: v1 : 53 pages, 1 figure; v2 : significantly shortened, 42 p., version
published in Class. Quant. Gra
Fermion correlators in non-abelian holographic superconductors
We consider fermion correlators in non-abelian holographic superconductors.
The spectral function of the fermions exhibits several interesting features
such as support in displaced Dirac cones and an asymmetric distribution of
normal modes. These features are compared to similar ones observed in angle
resolved photoemission experiments on high T_c superconductors. Along the way
we elucidate some properties of p-wave superconductors in AdS_4 and discuss the
construction of SO(4) superconductors.Comment: 49 pages, 11 figure
Classical Integrability of the Squashed Three-sphere, Warped AdS3 and Schroedinger Spacetime via T-Duality
We discuss the integrability of 2d non-linear sigma models with target space
being the squashed three-sphere, warped anti-de Sitter space and the
Schroedinger spacetime. These models can be obtained via T-duality from
integrable models. We construct an infinite family of non-local conserved
charges from the T-dual Lax currents, enhancing the symmetry of warped anti-de
Sitter space and the Schroedinger spacetime to sl2(R)+sl2(R).Comment: 29 Pages, 3 appendices. Minor changes: added references, footnot
Holographic Hall conductivities from dyonic backgrounds
We develop a general framework for computing the holographic 2-point
functions and the corresponding conductivities in asymptotically locally AdS
backgrounds with an electric charge density, a constant magentic field, and
possibly non-trivial scalar profiles, for a broad class of
Einstein-Maxwell-Axion-Dilaton theories, including certain Chern-Simons terms.
Holographic renormalization is carried out for any theory in this class and the
computation of the renormalized AC conductivities at zero spatial momentum is
reduced to solving a single decoupled first order Riccati equation. Moreover,
we develop a first order fake supergravity formulalism for dyonic
renormalization group flows in four dimensions, allowing us to construct
analytically infinite families of such backgrounds by specifying a
superpotential at will. These RG flows interpolate between AdS in the UV
and a hyperscaling violating Lifshitz geometry in the IR with exponents
and . For the spectrum of fluctuations is gapped and
discrete. Our hope and intention is that this analysis can serve as a manual
for computing the holographic 1- and 2-point functions and the corresponding
transport coefficients in any dyonic background, both in the context of AdS/CMT
and AdS/QCD
Holography for Schrodinger backgrounds
We discuss holography for Schrodinger solutions of both topologically massivegravity in three dimensions and massive vector theories in (d+1) dimensions. Inboth cases the dual field theory can be viewed as a d-dimensional conformalfield theory (two dimensional in the case of TMG) deformed by certain operatorsthat respect the Schrodinger symmetry. These operators are irrelevant from theviewpoint of the relativistic conformal group but they are exactly marginalwith respect to the non-relativistic conformal group. The spectrum of linearfluctuations around the background solutions corresponds to operators that arelabeled by their scaling dimension and the lightcone momentum k_v. We set upthe holographic dictionary and compute 2-point functions of these operatorsboth holographically and in field theory using conformal perturbation theoryand find agreement. The counterterms needed for holographic renormalization arenon-local in the v lightcone direction.<br/