4,884 research outputs found
Thermodynamics of Black Holes in Massive Gravity
We present a class of charged black hole solutions in an (-dimensional
massive gravity with a negative cosmological constant, and study thermodynamics
and phase structure of the black hole solutions both in grand canonical
ensemble and canonical ensemble. The black hole horizon can have a positive,
zero or negative constant curvature characterized by constant . By using
Hamiltonian approach, we obtain conserved charges of the solutions and find
black hole entropy still obeys the area formula and the gravitational field
equation at the black hole horizon can be cast into the first law form of black
hole thermodynamics. In grand canonical ensemble, we find that thermodynamics
and phase structure depends on the combination in the
four dimensional case, where is the chemical potential and is
the coefficient of the second term in the potential associated with graviton
mass. When it is positive, the Hawking-Page phase transition can happen, while
as it is negative, the black hole is always thermodynamically stable with a
positive capacity. In canonical ensemble, the combination turns out to be
in the four dimensional case. When it is positive, a first order
phase transition can happen between small and large black holes if the charge
is less than its critical one. In higher dimensional () case, even
when the charge is absent, the small/large black hole phase transition can also
appear, the coefficients for the third () and/or the fourth ()
terms in the potential associated with graviton mass in the massive gravity can
play the same role as the charge does in the four dimensional case.Comment: Latex 19 pages with 8 figure
Are gravitational wave ringdown echoes always equal-interval ?
Gravitational wave (GW) ringdown waveforms may contain "echoes" that encode
new physics in the strong gravity regime. It is commonly assumed that the new
physics gives rise to the GW echoes whose intervals are constant. We point out
that this assumption is not always applicable. In particular, if the
post-merger object is initially a wormhole, which slowly pinches off and
eventually collapses into a black hole, the late-time ringdown waveform exhibit
a series of echoes whose intervals are increasing with time. We also assess how
this affects the ability of Advanced LIGO/Virgo to detect these new signals.Comment: 10 pages,5 figure
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