503 research outputs found
On the thermodynamics of the black hole and hairy black hole transitions in the asymptotically flat spacetime with a box
We study the asymptotically flat quasi-local black hole/hairy black hole
model with nonzero mass of the scalar filed. We disclose effects of the scalar
mass on transitions in a grand canonical ensemble with condensation behaviors
of a parameter , which is similar to approaches in holographic
theories. We find that more negative scalar mass makes the phase transition
easier to happen. We also obtain an analytical relation
around the critical phase transition points
implying a second order phase transition. Besides the parameter , we
show that metric solutions can be used to disclose properties of transitions.
In this work, we observe that phase transitions in a box are strikingly similar
to holographic transitions in the AdS gravity and the similarity provides
insights into holographic theories.Comment: 12 pages, 6 figures. Accepted for publication in EPJC. arXiv admin
note: text overlap with arXiv:1705.0869
Non-equilibrium condensation process in holographic superconductor with nonlinear electrodynamics
We study the non-equilibrium condensation process in a holographic
superconductor with nonlinear corrections to the U(1) gauge field. We start
with an asymptotic Anti-de-Sitter(AdS) black hole against a complex scalar
perturbation at the initial time, and solve the dynamics of the gravitational
systems in the bulk. When the black hole temperature T is smaller than a
critical value Tc, the scalar perturbation grows exponentially till saturation,
the final state of spacetime approaches to a hairy black hole. In the bulk
theory, we find the clue of the influence of nonlinear corrections in the gauge
field on the process of the scalar field condensation. We show that the bulk
dynamics in the non-equilibrium process is completely consistent with the
observations on the boundary order parameter. Furthermore we examine the time
evolution of horizons in the bulk non-equilibrium transformation process from
the bald AdS black hole to the AdS hairy hole. Both the evolution of apparent
and event horizons show that the original AdS black hole configuration requires
more time to finish the transformation to become a hairy black hole if there is
nonlinear correction to the electromagnetic field. We generalize our
non-equilibrium discussions to the holographic entanglement entropy and find
that the holographic entanglement entropy can give us further understanding of
the influence of the nonlinearity in the gauge field on the scalar
condensation. In our analysis, we also compare the effect of different models
on the corrections to the gauge field on the formation of holographic
superconductor.Comment: 22 pages,accepted for publication in JHE
Polarizations of Gravitational Waves in Horndeski Theory
We analyze the polarization content of gravitational waves in Horndeski
theory. Besides the familiar plus and cross polarizations in Einstein's General
Relativity, there is one more polarization state which is the mixture of the
transverse breathing and longitudinal polarizations.The additional mode is
excited by the massive scalar field. In the massless limit, the longitudinal
polarization disappears, while the breathing one persists. The upper bound on
the graviton mass severely constrains the amplitude of the longitudinal
polarization, which makes its detection highly unlikely by the ground-based or
space-borne interferometers in the near future. However, pulsar timing arrays
might be able to detect the polarization excited by the massive scalar field.
Since additional polarization states appear in alternative theories of gravity,
the measurement of the polarizations of gravitational waves can be used to
probe the nature of gravity. In addition to the plus and cross states, the
detection of the breathing polarization means that gravitation is mediated by
massless spin 2 and spin 0 fields, and the detection of both the breathing and
longitudinal states means that gravitation is propagated by the massless spin 2
and massive spin 0 fields.Comment: 15 two column pages, 6 captioned figures, EPJC in pres
Signature of the Van der Waals like small-large charged AdS black hole phase transition in quasinormal modes
We calculate the quasinormal modes of massless scalar perturbations around
small and large four-dimensional Reissner-Nordstrom-Anti de Sitter (RN-AdS)
black holes. We find a dramatic change in the slopes of quasinormal frequencies
in small and large black holes near the critical point where the Van der Waals
like thermodynamic phase transition happens. This further supports that the
quasinormal mode can be a dynamic probe of the thermodynamic phase transition.Comment: 20 pages,11 figures.The new version is accepted for publication in
JHE
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