23 research outputs found
Holographic entanglement entropy in imbalanced superconductors
We study the behavior of holographic entanglement entropy (HEE) for
imbalanced holographic superconductors. We employ a numerical approach to
consider the robust case of fully back-reacted gravity system. The hairy black
hole solution is found by using our numerical scheme. Then it is used to
compute the HEE for the superconducting case. The cases we study show that in
presence of a mismatch between two chemical potentials, below the critical
temperature, superconducting phase has a lower HEE in comparison to the
AdS-Reissner-Nordstrom black hole phase. Interestingly, the effects of chemical
imbalance are different in the contexts of black hole and superconducting
phases. For black hole, HEE increases with increasing imbalance parameter while
it behaves oppositely for the superconducting phase. The implications of these
results are discussed.Comment: V2 (Published Version), 19 pages: We replace earlier analytical
method by numerical analysis. The effect of imbalance is more cleare
Hawking Radiation as a Mechanism for Inflation
The Friedman-Robertson-Walker (FRW) space-time exhibits particle creation
similar to Hawking radiation of a black hole. In this essay we show that this
FRW Hawking radiation leads to an effective negative pressure fluid which can
drive an inflationary period of exponential expansion in the early Universe.
Since the Hawking temperature of the FRW space-time decreases as the Universe
expands this mechanism naturally turns off and the inflationary stage
transitions to a power law expansion associated with an ordinary radiation
dominated Universe.Comment: 6 pages. Published version -- Awarded "Honorable Mention" for the
2012 Gravity Research Foundation Essay Contes
Inflation with a graceful exit and entrance driven by Hawking radiation
We present a model for cosmological inflation which has a natural "turn on"
and a natural "turn off" mechanism. In our model inflation is driven by the
Hawking-like radiation that occurs in Friedman-Robertson-Walker (FRW)
space-time. This Hawking-like radiation results in an effective negative
pressure "fluid" which leads to a rapid period of expansion in the very early
Universe. As the Universe expands the FRW Hawking temperature decreases and the
inflationary expansion turns off and makes a natural transition to the power
law expansion of a radiation dominated universe. The "turn on" mechanism is
more speculative, but is based on the common hypothesis that in a quantum
theory of gravity at very high temperatures/high densities Hawking radiation
will stop. Applying this speculation to the very early Universe implies that
the Hawking-like radiation of the FRW space-time will be turned off and
therefore the inflation driven by this radiation will turn off.Comment: 19 pages, 2 figures revtex, matches PRD published versio
Noncommutative Schwarzschild Black Hole and Area Law
Using a graphical analysis, we show that for the horizon radius , the standard semiclassical Bekenstein-Hawking area law for
noncommutative Schwarzschild black hole exactly holds for all orders of
. We also give the corrections to the area law to get the exact nature
of the Bekenstein-Hawking entropy when till the extremal
point .Comment: 11 pages, 8 figures, refs. added, minor modifications, to appear in
Class. Quant. Gra