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 $\beta-$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 $PA$ 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 $a=\sqrt{3}$. In that case when making a large $R$ expansion, the first law is satisfied up to $1/R$ order but it does not hold for higher sub-leading order of $R$. 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 $T_c$, 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 $SO(2,2) \times SO(3)$ isometry, which are AdS/CFT dual to 2D CFTs with $\mathcal{N} = (0,4)$ supersymmetry. We recover the Maldacena, Strominger, Witten (MSW) near-horizon with small superconformal symmetry and identify a class of $AdS_3 \times S^2 \times S^2 \times CY_2$ geometries with emergent large superconformal symmetry. This exhausts known compact geometries. Compactification of M-theory on $CY_2$ 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