13,547 research outputs found
Statistical mechanics of a two-dimensional black hole
The dynamics of a nearly-AdS2 spacetime with boundaries is reduced to two
particles in the anti-de Sitter space. We determine the class of physically
meaningful wavefunctions, and prescribe the statistical mechanics of a black
hole. We demonstrate how wavefunctions for a two-sided black hole and a
regularized notion of trace can be used to construct thermal partition
functions, and more generally, arbitrary density matrices. We also obtain
correlation functions of external operators.Comment: 33 pages + appendices; v.2: additional reference, explicit formula
for two-point correlators, and other minor improvement
The soft mode in the Sachdev-Ye-Kitaev model and its gravity dual
We give an exposition of the SYK model with several new results. A non-local
correction to the Schwarzian effective action is found. The same action is
obtained by integrating out the bulk degrees of freedom in a certain variant of
dilaton gravity. We also discuss general properties of out-of-time-order
correlators.Comment: 57 pages plus appendices, 6 figures. v.2: minor correction,
additional references. v.3: minor addition, additional references; v.4: minor
corrections; v.5: JHEP versio
Entanglement growth during thermalization in holographic systems
We derive in detail several universal features in the time evolution of
entanglement entropy and other nonlocal observables in quenched holographic
systems. The quenches are such that a spatially uniform density of energy is
injected at an instant in time, exciting a strongly coupled CFT which
eventually equilibrates. Such quench processes are described on the gravity
side by the gravitational collapse of a thin shell that results in a black
hole. Various nonlocal observables have a unified description in terms of the
area of extremal surfaces of different dimensions. In the large distance limit,
the evolution of an extremal surface, and thus the corresponding boundary
observable, is controlled by the geometry around and inside the event horizon
of the black hole, allowing us to identify regimes of pre-local- equilibration
quadratic growth, post-local-equilibration linear growth, a memory loss regime,
and a saturation regime with behavior resembling those in phase transitions. We
also discuss possible bounds on the maximal rate of entanglement growth in
relativistic systems.Comment: 36+11 pages, 21 figure
Four-point function in the IOP matrix model
The IOP model is a quantum mechanical system of a large- matrix oscillator
and a fundamental oscillator, coupled through a quartic interaction. It was
introduced previously as a toy model of the gauge dual of an AdS black hole,
and captures a key property that at infinite the two-point function decays
to zero on long time scales. Motivated by recent work on quantum chaos, we sum
all planar Feynman diagrams contributing to the four-point function. We find
that the IOP model does not satisfy the more refined criteria of exponential
growth of the out-of-time-order four-point function.Comment: 28 pages, 10 figure
A quantum electron star
We construct and probe a holographic description of state of matter which
results from coupling a Fermi liquid to a relativistic conformal field theory
(CFT). The bulk solution is described by a quantum gas of fermions supported
from collapse into the gravitational well of AdS by their own electrostatic
repulsion. In the probe limit studied here, the Landau quasiparticles survive
this coupling to a CFT.Comment: 8 pages, 7 figure
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