85 research outputs found
Resolving the black hole information paradox
The recent progress in string theory strongly suggests that formation and
evaporation of black holes is a unitary process. This fact makes it imperative
that we find a flaw in the semiclassical reasoning that implies a loss of
information. We propose a new criterion that limits the domain of classical
gravity: the hypersurfaces of a foliation cannot be stretched too much. This
conjectured criterion may have important consequences for the early Universe.Comment: harvmac, 11 pages (1 figure) (This essay received an ``honorable
mention'' in the Annual Essay Competition of the Gravity Research Foundation
for the year 2000.
On the Effective Equation of State of Dark Energy
In an effective field theory model with an ultraviolet momentum cutoff, there
is a relation between the effective equation of state of dark energy and the
ultraviolet cutoff scale. It implies that a measure of the equation of state of
dark energy different from minus one, does not rule out vacuum energy as dark
energy. It also indicates an interesting possibility that precise measurements
of the infrared properties of dark energy can be used to probe the ultraviolet
cutoff scale of effective quantum field theory coupled to gravity. In a toy
model with a vacuum energy dominated universe with a Planck scale cutoff, the
dark energy effective equation of state is -0.96.Comment: 7 pages, awarded honorable mention in the 2010 Gravity Research
Foundation essay competitio
AdS_3/CFT_2 correspondence at finite temperature
The AdS/CFT correspondence is established for the AdS_3 space compactified on
a solid torus with the CFT field on the boundary. Correlation functions that
correspond to the bulk theory at finite temperature are obtained in the
regularization a'la Gubser, Klebanov, and Polyakov. The BTZ black hole
solutions in AdS_3 are T-dual to the solution in the AdS_3 space without
singularity.Comment: 9pp., LaTe
Time dependence of entanglement for steady state formation in AdS/CFT
We consider a holographic model of two 1+1-dimensional heat baths at
different temperatures joined at time , such that a steady state
heat-current region forms and expands in space for times . After
commenting on the causal structure of the dual 2+1-dimensional spacetime, we
present how to calculate the time-dependent entanglement entropy of the
boundary system holographically. We observe that the increase rate of the
entanglement entropy satisfies certain bounds known from the literature on
entanglement tsunamis. Furthermore, we check the validity of several
non-trivial entanglement inequalities in this dynamic system.Comment: 6 pages, 6 figures, these proceedings summarize a talk given at the
Karl Schwarzschild Meeting 2017 and the much longer paper 1705.04696. v2:
reference adde
A not so brief commentary on cosmological entropy bounds
There has been, quite recently, a discussion on how holographic-inspired
bounds might be used to encompass the present-day dark energy and
early-universe inflation into a single paradigm. In the current treatment, we
point out an inconsistency in the proposed framework and then provide a viable
resolution. We also elaborate on some of the implications of this framework and
further motivate the proposed holographic connection. The manuscript ends with
a more speculative note on cosmic time as an emergent (holographically induced)
construct.Comment: 12 pages and Revtex; (v2) reference added and a few cosmetic change
Dark solitons in holographic superfluids
5 pages, Revtex, 5 figures, some typos corrected. Reference addedWe construct dark soliton solutions in a holographic model of a relativistic superfluid. We study the length scales associated with the condensate and the charge density depletion, and find that the two scales differ by a non-trivial function of the chemical potential. By adjusting the chemical potential, we study the variation of the depletion of charge density at the interface.Peer reviewe
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