22 research outputs found
Minimal redefinition of the OSV ensemble
In the interesting conjecture, Z_{BH} = |Z_{top}|^2, proposed by Ooguri,
Strominger and Vafa (OSV), the black hole ensemble is a mixed ensemble and the
resulting degeneracy of states, as obtained from the ensemble inverse-Laplace
integration, suffers from prefactors which do not respect the electric-magnetic
duality. One idea to overcome this deficiency, as claimed recently, is imposing
nontrivial measures for the ensemble sum. We address this problem and upon a
redefinition of the OSV ensemble whose variables are as numerous as the
electric potentials, show that for restoring the symmetry no non-Euclidean
measure is needful. In detail, we rewrite the OSV free energy as a function of
new variables which are combinations of the electric-potentials and the black
hole charges. Subsequently the Legendre transformation which bridges between
the entropy and the black hole free energy in terms of these variables, points
to a generalized ensemble. In this context, we will consider all the cases of
relevance: small and large black holes, with or without D_6-brane charge. For
the case of vanishing D_6-brane charge, the new ensemble is pure canonical and
the electric-magnetic duality is restored exactly, leading to proper results
for the black hole degeneracy of states. For more general cases, the
construction still works well as far as the violation of the duality by the
corresponding OSV result is restricted to a prefactor. In a concrete example we
shall show that for black holes with non-vanishing D_6-brane charge, there are
cases where the duality violation goes beyond this restriction, thus imposing
non-trivial measures is incapable of restoring the duality. This observation
signals for a deeper modification in the OSV proposal.Comment: 23 pages, v2: minor change
Electron stars for holographic metallic criticality
We refer to the ground state of a gravitating, charged ideal fluid of
fermions held at a finite chemical potential as an `electron star'. In a
holographic setting, electron stars are candidate gravity duals for strongly
interacting finite fermion density systems. We show how electron stars develop
an emergent Lifshitz scaling at low energies. This IR scaling region is a
consequence of the two way interaction between emergent quantum critical
bosonic modes and the finite density of fermions. By integrating from the IR
region to an asymptotically AdS_4 spacetime, we compute basic properties of the
electron stars, including their electrical conductivity. We emphasize the
challenge of connecting UV and IR physics in strongly interacting finite
density systems.Comment: 1+28 pages. LaTeX. 4 figures. v2 reference added, typos fixe
Does Quantum Mechanics Breed Larger, More Intricate Quantum Theories? The Case for Experience-Centric Quantum Theory and the Interactome of Quantum Theories
We pose and address the radical question that whether quantum mechanics,
known for its firm internal structure and enormous empirical success, carries
in itself the genome of larger quantum theories which have higher internal
intricacies and phenomenological versatilities. That is, on the basic level of
closed quantum systems and regardless of interpretational aspects, whether
standard quantum theory (SQT) harbors quantum theories with context-based
deformed principles or structures, having definite predictive power within
broader scopes. We answer the question in affirmative following complementary
evidence and reasoning arising from quantum-computation-based quantum
simulation and fundamental, general, abstract rationales in the frameworks of
information theory, fundamental or functional emergence, and participatory
agency. In this light, as we show, one is led to the recently proposed
experience-centric quantum theory (ECQT), which is a larger and richer theory
of quantum behaviors with drastically generalized quantum dynamics. ECQT allows
the quantum information of the closed quantum system's developed state history
to continually contribute to defining manybody interactions, Hamiltonians, and
even internal elements and ``particles'' of the total system. Hence the unitary
evolutions are continually impacted and become guidable by the agent-system's
experience. The intrinsic interplay of unitarity and non-Markovianity in ECQT
brings about a host of diverse behavioral phases, which concurrently infuse
closed and open quantum system characteristics and even surpasses the theory of
open systems in SQT. In the broader perspective, an upshot of our investigation
is the existence of the quantum interactome--the interactive landscape of all
coexisting, independent context-based quantum theories which emerge from
inferential participatory agencies--and its predictive phenomenological
utility.Comment: 54 page
Critical formation of trapped surfaces in the collision of gravitational shock waves
We study the formation of marginally trapped surfaces in the head-on
collision of two shock waves both in anti-de Sitter and Minkowski space-time in
various dimensions as a function of the spread of the energy density in
transverse space. For D=4 and D=5 it is shown that there exists a critical
value of this spread above which no solution to the trapped surface equation is
found. In four dimensions the trapped surface at criticality has a finite size,
whereas in five the critical size vanishes. In both cases we find scaling
relations characterized by critical exponents. Finally, when D>5 there is
always a solution to the trapped surface equation for any transverse spread.Comment: 16 page
Critical gravitational collapse: towards a holographic understanding of the Regge region
81 pages, 31 figures.We study the possible holographic connection between the Regge limit in QCD and critical gravitational collapse of a perfect fluid in higher dimensions. We begin by analyzing the problem of critical gravitational collapse of a perfect fluid in any number of dimensions and numerically compute the associated Choptuik exponent in d=5, 6 and 7 for a range of values of the speed of sound of the fluid. Using continuous self-similarity as guiding principle, a holographic correspondence between this process and the phenomenon of parton saturation in high-energy scattering in QCD is proposed. This holographic connection relates strong gravitational physics in the bulk with (nonsupersymmetric) QCD at weak coupling in four dimensions.The work of C.G. has been partially supported by the Spanish DGI contract FPA2003-02877 and the CAM grant HEPHACOS P-ESP-00346. A.T. thanks the Marie Curie and the Freydoon Mansouri foundations for support, and the CERN Theory Group for hospitality. M.A.V.-M. acknowledges partial support from the Spanish Government Grants PA2005-04823, FIS2006-05319 and Spanish Consolider-Ingenio 2010 Programme CPAN
(CSD2007-00042), and thanks the CERN Theory Group for hospitality
Black Holes and Large Order Quantum Geometry
We study five-dimensional black holes obtained by compactifying M theory on
Calabi-Yau threefolds. Recent progress in solving topological string theory on
compact, one-parameter models allows us to test numerically various conjectures
about these black holes. We give convincing evidence that a microscopic
description based on Gopakumar-Vafa invariants accounts correctly for their
macroscopic entropy, and we check that highly nontrivial cancellations -which
seem necessary to resolve the so-called entropy enigma in the OSV conjecture-
do in fact occur. We also study analytically small 5d black holes obtained by
wrapping M2 branes in the fiber of K3 fibrations. By using heterotic/type II
duality we obtain exact formulae for the microscopic degeneracies in various
geometries, and we compute their asymptotic expansion for large charges.Comment: 42 pages, 20 eps figures, small correction