https://doi.org/10.1140/epjc/s10052-018-6422-8
Regular Article - Theoretical Physics
The Reissner–Nordström black hole with the fastest relaxation rate
1
The Ruppin Academic Center, 40250, Emeq Hefer, Israel
2
The Hadassah Academic College, 91010, Jerusalem, Israel
* e-mail: shaharhod@gmail.com
Received:
12
September
2018
Accepted:
5
November
2018
Published online:
14
November
2018
Numerous numerical investigations of the quasinormal resonant spectra of Kerr-Newman black holes have revealed the interesting fact that the characteristic relaxation times 
of these canonical black-hole spacetimes can be described by a two-dimensional function 
which increases monotonically with increasing values of the dimensionless angular-momentum parameter 
and, in addition, is characterized by a non-trivial (non-monotonic) functional dependence on the dimensionless charge parameter 
. In particular, previous numerical investigations have indicated that, within the family of spherically symmetric charged Reissner–Nordström spacetimes, the black hole with 
has the fastest relaxation rate. In the present paper we use analytical techniques in order to investigate this intriguing non-monotonic functional dependence of the Reissner–Nordström black-hole relaxation rates on the dimensionless physical parameter 
. In particular, it is proved that, in the eikonal (geometric-optics) regime, the black hole with 
is characterized by the fastest relaxation rate (the smallest dimensionless relaxation time 
) within the family of charged Reissner–Nordström black-hole spacetimes.
© The Author(s), 2018
