18,787 research outputs found
Structure of Quantum Chaotic Wavefunctions: Ergodicity, Localization, and Transport
We discuss recent developments in the study of quantum wavefunctions and
transport in classically ergodic systems. Surprisingly, short-time classical
dynamics leaves permanent imprints on long-time and stationary quantum
behavior, which are absent from the long-time classical motion. These imprints
can lead to quantum behavior on single-wavelength or single-channel scales
which are very different from random matrix theory expectations. Robust and
quantitative predictions are obtained using semiclassical methods. Applications
to wavefunction intensity statistics and to resonances in open systems are
discussed.Comment: 8 pages, including 2 figures; talk given at `Dynamics of Complex
Systems' workshop in Dresden, 1999 and submitted for conference proceedings
to appear in Physica
A Numerical Approach to Virasoro Blocks and the Information Paradox
We chart the breakdown of semiclassical gravity by analyzing the Virasoro
conformal blocks to high numerical precision, focusing on the heavy-light limit
corresponding to a light probe propagating in a BTZ black hole background. In
the Lorentzian regime, we find empirically that the initial exponential
time-dependence of the blocks transitions to a universal
power-law decay. For the vacuum block the transition occurs at , confirming analytic predictions. In the Euclidean regime,
due to Stokes phenomena the naive semiclassical approximation fails completely
in a finite region enclosing the `forbidden singularities'. We emphasize that
limitations on the reconstruction of a local bulk should ultimately stem from
distinctions between semiclassical and exact correlators.Comment: 45 pages, 23 figure
Antikaon Production and Medium Effects in Heavy Ion Collisions at AGS
Antikaon production from heavy ion collisions at energies available from the
Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratory is
studied in a relativistic transport (ART) model. We include contributions from
the baryon-baryon, meson-baryon, and meson-meson interactions. The final-state
interaction of antikaons via both absorption and elastic scattering by nucleons
and pions are also considered. To compare with presently available or future
experimental data, we have calculated the antikaon rapidity and transverse
momentum distributions as well as its collective flow. Medium effects on these
observables due to mean field potentials have also been investigated. It is
found that the ratio of antikaon transverse momentum spectrum to that of kaon
and their transverse flow are most sensitive to the in-medium properties of
kaons and antikaons.Comment: 19 pages, 13 figure
Exact Virasoro Blocks from Wilson Lines and Background-Independent Operators
Aspects of black hole thermodynamics and information loss can be derived as a
consequence of Virasoro symmetry. To bolster the connection between Virasoro
conformal blocks and AdS quantum gravity, we study sl Chern-Simons
Wilson line networks and revisit the idea that they compute a variety of
CFT observables, including Virasoro OPE blocks, exactly. We verify this in
the semiclassical large central charge limit and to low orders in a
perturbative expansion.
Wilson lines connecting the boundary to points in the bulk play a natural
role in bulk reconstruction. Because quantum gravity in AdS is rigidly
fixed by Virasoro symmetry, we argue that sl Wilson lines provide building
blocks for background independent bulk reconstruction. In particular, we show
explicitly that they automatically compute the uniformizing coordinates
appropriate to any background state.Comment: V3- Added some references V2- Significantly Expanded Appendix on
Regulation; 32+21 page
The Bulk-to-Boundary Propagator in Black Hole Microstate Backgrounds
First-quantized propagation in quantum gravitational AdS backgrounds can
be exactly reconstructed using CFT data and Virasoro symmetry. We develop
methods to compute the bulk-to-boundary propagator in a black hole microstate,
, at finite
central charge. As a first application, we show that the semiclassical theory
on the Euclidean BTZ solution sharply disagrees with the exact description, as
expected based on the resolution of forbidden thermal singularities, though
this effect may appear exponentially small for physical observers.Comment: 34+27 pages, 7 figures; v2: typos correcte
The AdS Propagator and the Fate of Locality
We recently used Virasoro symmetry considerations to propose an exact formula
for a bulk proto-field in AdS. In this paper we study the propagator
. We show that many techniques from the study of
conformal blocks can be generalized to compute it, including the semiclassical
monodromy method and both forms of the Zamolodchikov recursion relations. When
the results from recursion are expanded at large central charge, they match
gravitational perturbation theory for a free scalar field coupled to gravity in
our chosen gauge.
We find that although the propagator is finite and well-defined at long
distances, its perturbative expansion in exhibits UV/IR
mixing effects. If we nevertheless interpret as a
probe of bulk locality, then when locality breaks down at
the new short-distance scale . For
with very large bulk mass, or at small central charge, bulk locality
fails at the AdS length scale. In all cases, locality `breakdown' manifests as
singularities or branch cuts at spacelike separation arising from
non-perturbative quantum gravitational effects.Comment: 42+17 pages, 7 figure
Wavefunction Statistics using Scar States
We describe the statistics of chaotic wavefunctions near periodic orbits
using a basis of states which optimise the effect of scarring. These states
reflect the underlying structure of stable and unstable manifolds in phase
space and provide a natural means of characterising scarring effects in
individual wavefunctions as well as their collective statistical properties. In
particular, these states may be used to find scarring in regions of the
spectrum normally associated with antiscarring and suggest a characterisation
of templates for scarred wavefunctions which vary over the spectrum. The
results are applied to quantum maps and billiard systems.Comment: 31 pages, 11 figures, to appear in Annals of Physic
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