8,725 research outputs found
Time Evolution of Temperature and Entropy of Various Collapsing Domain Walls
We investigate the time evolution of the temperature and entropy of
gravitationally collapsing domain walls as seen by an asymptotic observer. In
particular, we seek to understand how topology and the addition of a
cosmological constant affect the gravitational collapse. Previous work has
shown that the entropy of a spherically symmetric collapsing domain approaches
a constant. In this paper, we reproduce these results, using both a fully
quantum and a semi-classical approach, then we repeat the process for a de
Sitter Schwarzschild domain wall (spherical with cosmological constant) and a
(3+1) BTZ domain wall (cylindrical). We do this by coupling a scalar field to
the background of the domain wall and analyzing the spectrum of radiation as a
function of time. We find that the spectrum is quasi-thermal, with the degree
of thermality increasing as the domain wall approaches the horizon. The thermal
distribution allows for the determination of the temperature as a function of
time, and we find that the late time temperature is very close to the Hawking
temperature and that it also exhibits the proper scaling with the mass. From
the temperature we find the entropy. Since the collapsing domain wall is what
forms a black hole, we can compare the results to those of the standard
entropy-area relation. We find that the entropy does in fact approach a
constant that is close to the Hawking entropy. However, both the de Sitter
Schwarzschild domain wall and the (3+1) BTZ domain wall show periods of
decreasing entropy, which suggests that spontaneous collapse may be prevented.Comment: This paper is a merging of two previously submitted papers: Time
Evolution of Temperature and Entropy of a Gravitationally Collapsing Cylinder
[arXiv:1106.2278]; Time Evolution of Temperature and Entropy of a
Gravitationally Collapsing de Sitter Schwarzschild Domain Wal
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