55 research outputs found
An emergent geometric description for a topological phase transition in the Kitaev superconductor model
Resorting to Wilsonian renormalization group (RG) transformations, we propose
an emergent geometric description for a topological phase transition in the
Kitaev superconductor model. An effective field theory consists of an emergent
bulk action with an extra dimension, an ultraviolet (UV) boundary condition for
an initial value of a coupling function, and an infrared (IR) effective action
with a fully renormalized coupling function. The bulk action describes the
evolution of the coupling function along the direction of the extra dimension,
where the extra dimension is identified with an RG scale and the resulting
equation of motion is nothing but a function. In particular, the IR
effective field theory turns out to be consistent with a Callan-Symanzik
equation which takes into account both the bulk and IR boundary contributions.
This derived Callan-Symanzik equation gives rise to a metric structure. Based
on this emergent metric tensor, we uncover the equivalence of the entanglement
entropy between the emergent geometric description and the quantum field theory
in the vicinity of the quantum critical point.Comment: Two figures adde
Quasilocal Smarr relation for an asymptotically flat spacetime
A quasilocal Smarr relation is obtained from Euler's theorem for
Einstein-Maxwell(-Dilaton) theory for an asymptotically flat spacetime, and its
associated first law is studied. To check both, we calculate quasilocal
variables by employing Brown-York quasilocal method along with Mann-Marolf
counterterms, which are consistent with Tolman temperature. We also derive
entropy by constructing a quasilocal thermodynamic potential via Euclidean
method. Here we found that the Euclidean action value in a quasilocal frame
just yields a usual thermodynamic potential form, which do not include a
term, and entropy just becomes the Bekenstein-Hawking one. Through the
examples, we confirmed that our quasilocal Smarr relation is satisfied with all
cases, and its first law is also exactly satisfied except the dyonic black hole
with the dilaton coupling constant . In that case when making a
large expansion, the first law is satisfied up to order but it does
not hold for higher sub-leading order of . This issue should be resolved in
future.Comment: 24 page
Black Holes in Einstein-scalar-Gauss-Bonnet model probed with scattering amplitudes
We examined the quantum properties of scalar-tensor gravity with a coupling
to the Gauss-Bonnet term, exploring both linear and quadratic couplings. We
calculate the leading order corrections to the non-relativistic one-body
gravitational potential and the metric studying the external gravitational
field of a point-like scalar particle. The light-like scattering was studied
and compared with the classical theory. We find that loop corrections are
strongly suppressed and cannot significantly affect the black hole shadow for
quadratic coupling. The leading order corrections are important for small-angle
scattering and can contribute to the formation of the black hole shadow for the
case of linear coupling.Comment: 23 pages, 4 figures. New references added in version
Dynamical Condensation in a Holographic Superconductor Model with Anisotropy
We study dynamical condensation process in a holographic superconductor model
with anisotropy. The time-dependent numerical solution is constructed for the
Einstein-Maxwell-dilaton theory with complex scalar in asymptotic AdS
spacetime. The introduction of dilaton field generates the anisotropy in
boundary spatial directions. In analogy of isotropic case, we have two black
hole solutions below certain critical temperature , the anisotropic
charged black hole with and without scalar hair, corresponding respectively to
the supercooled normal phase and superconducting phase in the boundary theory.
We observe a nonlinear evolution from a supercooled anisotropic black hole
without scalar hair to a anisotropic hairy black hole. Via AdS/CFT
correspondence, we extract time evolution of the condensate operator, which
shows an exponential growth and subsequent saturation, similar to the isotropic
case. Furthermore, we obtain a nontrivial time evolution of the boundary
pressure, while in isotropic case it remains a constant. We also generalize
quasinormal modes calculation to anisotropic black holes and shows scalar
quasinormal modes match with relaxation time scale of the condensate operator.
In addition, we present the final temperature and anisotropic pressure as
functions of initial temperature and background anisotropy.Comment: 18 pages, 12 figures. v2: minor revision and references adde
Large superconformal near-horizons from M-theory
We report on a classification of supersymmetric solutions to 11D supergravity
with isometry, which are AdS/CFT dual to 2D CFTs with
supersymmetry. We recover the Maldacena, Strominger,
Witten (MSW) near-horizon with small superconformal symmetry and identify a
class of geometries with emergent
large superconformal symmetry. This exhausts known compact geometries.
Compactification of M-theory on results in a vacuum of 7D supergravity
with large superconformal symmetry, providing a candidate near-horizon for an
extremal black hole and a potential new setting to address microstates.Comment: 5 pages; v2 6 pages, catchier title, rewritten introduction,
references added, details of consistent truncation from 11D to 7D
supergravity added, conclusions unchange
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