Physics Letters B 756 (2016) 365–370
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Classical and quantum equations of motion of an n-dimensional BTZ
black hole
Eric Greenwood
Department of Geology and Physics, University of Southern Indiana, Evansville, IN 47712, United States
a r t i c l e i n f o a b s t r a c t
Article history:
Received
18 December 2015
Received
in revised form 7 March 2016
Accepted
15 March 2016
Available
online 19 March 2016
Editor:
M. Cveti
ˇ
c
We investigate the gravitational collapse of a non-rotating n-dimensional BTZ black hole in AdS space in
the context of both classical and quantum mechanics. This is done by first deriving the conserved mass
of a “spherically” symmetric domain wall, which is taken as the classical Hamiltonian of the black hole.
Upon deriving the conserved mass, we also point out that, for a “spherically” symmetric shell, there is an
easy and straight-forward way of determining the conserved mass, which is related to the proper time
derivative of the interior and exterior times. This method for determining the conserved mass is generic
to any situation (i.e. any equation of state), since it only depends on the energy per unit area, σ , of the
shell.
Classically,
we show that the time taken for gravitational collapse follows that of the typical formation of
a black hole via gravitational collapse; that is, an asymptotic observer will see that the collapse takes an
infinite amount of time to occur, while an infalling observer will see the collapse to both the horizon and
the classical singularity occur in a finite amount of time. Quantum mechanically, we take primary interest
in the behavior of the collapse near the horizon and near the classical singularity from the point of view
of both asymptotic and infalling observers. In the absence of radiation and fluctuations of the metric,
quantum effects near the horizon do not change the classical conclusions for an asymptotic observer. The
most interesting quantum mechanical effect comes in when investigating near the classical singularity.
Here, we find, that the quantum effects in this region are able to remove the classical singularity at the
origin, since the wave function is non-singular, and it also displays non-local effects, which depend on
the energy density of the domain wall.
© 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP
3
.
1. Introduction
The question of gravitational collapse is always an interest-
ing
question in theoretical physics; whether it be to study the
classical formation of a black hole [1–4], quantum formation of
a black hole [5], induced quasi-particle production [6], or ther-
malization
processes [7,8] and different kinds of entropies [9–11]
within
the context of the AdS/CFT correspondence and the Func-
tional
Schrödinger formalism. Moreover, due to the applications
using the AdS/CFT correspondence, gravitational collapse in AdS
has become of greater importance. Therefore, it is worth investi-
gating
the gravitational collapse of an n-dimensional, massive, BTZ
black hole in AdS. In this paper we will investigate the gravita-
tional
collapse in the context of the Gauss–Codazzi equations.
E-mail address: egreenwood@usi.edu.
In Section 2 we review the Gauss–Codazzi equations. Here,
we are interested in the Gauss–Codazzi equations for a general,
spherically symmetric, (n − 1)-dimensional hypersurface embed-
ded
in an n-dimensional space–time. Upon reviewing the Gauss–
Codazzi
equations, we also point out a straight-forward method for
determining the conserved mass of the collapsing shell, which only
depends on the proper-time derivative of the interior and external
time coordinates. In Section 3 we specialize to an n-dimensional
BTZ black hole and derive the conserved mass using the straight-
forward
method found in Section 2. Since the mass is a conserved
quantity, we may treat it as the Hamiltonian of the collapsing shell,
which we will use to derive the classical and quantum equations of
motion for different observers. Here, we have chosen the most rel-
evant
observers; the asymptotic, which is stationary at spatial in-
finity,
and infalling (one who is falling together with the collapsing
domain wall). The quantum collapse for both observers is obtained
by utilizing a minisuperspace version of the functional Schrödinger
http://dx.doi.org/10.1016/j.physletb.2016.03.041
0370-2693/
© 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP
3
.