1,696 research outputs found
Black hole thermalization rate from brane anti-brane model
We develop the quasi-particle picture for Schwarzchild and far from extremal
black holes. We show that the thermalization equations of the black hole is
recovered from the model of branes and anti-branes. This can also be viewed as
a field theory explanation of the relationship between area and entropy for
these black holes. As a by product the annihilation rate of branes and
anti-branes is computed.Comment: 11 pages, late
Hall viscosity from gauge/gravity duality
In (2+1)-dimensional systems with broken parity, there exists yet another
transport coefficient, appearing at the same order as the shear viscosity in
the hydrodynamic derivative expansion. In condensed matter physics, it is
referred to as "Hall viscosity". We consider a simple holographic realization
of a (2+1)-dimensional isotropic fluid with broken spatial parity. Using
techniques of fluid/gravity correspondence, we uncover that the holographic
fluid possesses a nonzero Hall viscosity, whose value only depends on the
near-horizon region of the background. We also write down a Kubo's formula for
the Hall viscosity. We confirm our results by directly computing the Hall
viscosity using the formula.Comment: 12 page
Shear viscosity from R-charged AdS black holes
We compute the shear viscosity in the supersymmetric Yang-Mills theory dual
to the STU background. This is a thermal gauge theory with a chemical
potential. The quotient of the shear viscosity over the entropy density
exhibits no deviation from the well known result 1/4\pi.Comment: 9 pages, some references updated, abstract and some typos correcte
Black Hole Entropy and Superconformal Field Theories on Brane-Antibrane Systems
We obtain the enropy of Schwarzschild and charged black holes in D>4 from
superconformal gases that live on p=10-D dimensional brane-antibrane systems
wrapped on T^p. The preperties of the strongly coupled superconformal theories
such as the appearance of hidden dimensions (for p=1,4) and fractional strings
(for p=5) are crucial for our results. In all cases, the Schwarzschild radius
is given by the transverse fluctuations of the branes and antibranes due to the
finite temperature. We show that our results can be generalized to multicharged
black holes.Comment: 24 pages in phyzzx.te
Field-induced quantum fluctuations in the heavy fermion superconductor CeCu2Ge2
Quantum-mechanical fluctuations in strongly correlated electron systems cause
unconventional phenomena such as non-Fermi liquid behavior, and arguably high
temperature superconductivity. Here we report the discovery of a field-tuned
quantum critical phenomenon in stoichiometric CeCu2Ge2, a spin density wave
ordered heavy fermion metal that exhibits unconventional superconductivity
under ~ 10 GPa of applied pressure. Our finding of the associated quantum
critical spin fluctuations of the antiferromagnetic spin density wave order,
dominating the local fluctuations due to single-site Kondo effect, provide new
information about the underlying mechanism that can be important in
understanding superconductivity in this novel compound.Comment: Heavy Fermion, Quantum Critical Phenomeno
String Theory and Quantum Chromodynamics
I review recent progress on the connection between string theory and quantum
chromodynamics in the context of the gauge/gravity duality. Emphasis is placed
on conciseness and conceptual aspects rather than on technical details. Topics
covered include the large-Nc limit of gauge theories, the gravitational
description of gauge theory thermodynamics and hydrodynamics, and
confinement/deconfinement thermal phase transitions.Comment: 38 pages, 24 figures. Lectures given at the RTN Winter School on
"Strings, Supergravity and Gauge Theories" at CERN on January 15-19, 200
Properties of some conformal field theories with M-theory duals
By studying classes of supersymmetric solutions of D=11 supergravity with
AdS_5 factors, we determine some properties of the dual four-dimensional N=1
superconformal field theories. For some explicit solutions we calculate the
central charges and also the conformal dimensions of certain chiral primary
operators arising from wrapped membranes. For the most general class of
solutions we show that there is a consistent Kaluza-Klein truncation to minimal
D=5 gauged supergravity. This latter result allows us to study some aspects of
the dual strongly coupled thermal plasma with a non-zero R-charge chemical
potential and, in particular, we show that the ratio of the shear viscosity to
the entropy density has the universal value of 1/4 pi.Comment: Consistent truncation extended to include fermions. Reference added.
28 page
Non-BPS D-brane Near NS5-branes
We use tachyon field theory effective action to study the dynamics of a
non-BPS Dp-brane propagating in the vicinity of k NS5-branes. For the time
dependent tachyon condensation we will concentrate on the case of the large
tachyon and the case when a non-BPS D-brane is close to NS5-branes. For spatial
dependent tachyon condensation we will argue that the problem reduces to the
study of the motion of an array of D(p-1)-branes and D(p-1)-antibranes in the
vicinity of k NS5-branes.Comment: 21 page
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