25 research outputs found
Analytic black branes in Lifshitz-like backgrounds and thermalization
Using black brane solutions in 5d Lifshitz-like backgrounds with arbitrary
dynamical exponent , we construct the Vaidya geometry, asymptoting to the
Lifshitz-like spacetime, which represents a thin shell infalling at the speed
of light. We apply the new Lifshitz-Vaidya background to study the
thermalization process of the quark-gluon plasma via the thin shell approach
previously successfully used in several backgrounds. We find that the
thermalization depends on the chosen direction because of the spatial
anisotropy. The plasma thermalizes thus faster in the transversal direction
than in the longitudinal one. To probe the system described by the
Lifshitz-like backgrounds, we also calculate the holographic entanglement
entropy for the subsystems delineated along both transversal and longitudinal
directions. We show that the entropy has some universality in the behavior for
both subsystems. At the same time, we find that certain characteristics
strongly depend on the critical exponent .Comment: 39 pages, 23 figures; v3: typos corrected, references and
clarifications added, version published in JHE
Thermalization after holographic bilocal quench
We study thermalization in the holographic (1+1)-dimensional CFT after
simultaneous generation of two high-energy excitations in the antipodal points
on the circle. The holographic picture of such quantum quench is the creation
of BTZ black hole from a collision of two massless particles. We perform
holographic computation of entanglement entropy and mutual information in the
boundary theory and analyze their evolution with time. We show that
equilibration of the entanglement in the regions which contained one of the
initial excitations is generally similar to that in other holographic quench
models, but with some important distinctions. We observe that entanglement
propagates along a sharp effective light cone from the points of initial
excitations on the boundary. The characteristics of entanglement propagation in
the global quench models such as entanglement velocity and the light cone
velocity also have a meaning in the bilocal quench scenario. We also observe
the loss of memory about the initial state during the equilibration process. We
find that the memory loss reflects on the time behavior of the entanglement
similarly to the global quench case, and it is related to the universal linear
growth of entanglement, which comes from the interior of the forming black
hole. We also analyze general two-point correlation functions in the framework
of the geodesic approximation, focusing on the study of the late time behavior.Comment: 75 pages, 41 figure, v2: typos corrected, references and minor
comments added, v3: published versio
Taming the Non Abelian Born-Infeld Action
We show how to reduce the non abelian Born-Infeld action describing the
interaction of two D-particles to the sum of elliptic integrals depending on
simple kinematic invariants. This representation gives explicitly all alpha'
corrections to D-particle dynamics. The alpha' corrections induce a
stabilization of the classical trajectories such as the ``eikonal'' which are
unstable within the Yang-Mills approximation.Comment: 17 pages, Latex, 6 figure
Stringy Model of Cosmological Dark Energy
A string field theory(SFT) nonlocal model of the cosmological dark energy
providing w<-1 is briefly surveyed. We summarize recent developments and open
problems, as well as point out some theoretical issues related with others
applications of the SFT nonlocal models in cosmology, in particular, in
inflation and cosmological singularity.Comment: Talk at PASCOS 2007, to appear in the proceedings, 5 pages, late
Thermalization of holographic Wilson loops in spacetimes with spatial anisotropy
In this paper, we study behaviour of Wilson loops in the boost-invariant
nonequilibrium anisotropic quark-gluon plasma produced in heavy-ion collisions
within the holographic approach. We describe the thermalization studying the
evolution of the Vaidya metric in the boost-invariant and spatially anisotropic
background. To probe the system during this process we calculate rectangular
Wilson loops oriented in different spatial directions. We find that anisotropic
effects are more visible for the Wilson loops lying in the transversal plane
unlike the Wilson loops with partially longitudinal orientation. In particular,
we observe that the Wilson loops can thermalizes first unlike to the order of
the isotropic model. We see that Wilson loops on transversal contours have the
shortest thermalization time. We also calculate the string tension and the
pseudopotential at different temperatures for the static quark-gluon plasma. We
show that the pseudopotential related to the configuration on the transversal
plane has the screened Cornell form. We also show that the jet-quenching
parameter related with the average of the light-like Wilson loop exhibits the
dependence on orientations.Comment: 39 pages, 12 figures; v3: typos corrected, to appear in Nucl. Phys.
Holographic local quench and effective complexity
We study the evolution of holographic complexity of pure and mixed states in
-dimensional conformal field theory following a local quench using both
the "complexity equals volume" (CV) and the "complexity equals action" (CA)
conjectures. We compare the complexity evolution to the evolution of
entanglement entropy and entanglement density, discuss the Lloyd computational
bound and demonstrate its saturation in certain regimes. We argue that the
conjectured holographic complexities exhibit some non-trivial features
indicating that they capture important properties of what is expected to be
effective (or physical) complexity.Comment: 33 pages, 19 figures; v2: typos corrected; 35 pages, references
added, new appendix. Version to match published in JHE