Mariano Chernicoff

A bstract: We compute the one-loop contribution to the semiclassical partition function of near-extremal, asymptotically AdS black holes in five-dimensional Einstein-Gauss-Bonnet gravity. In the absence of an exact analytic rotating solution at finite Gauss-Bonnet coupling α , we restrict to static, charged configurations and evaluate the contribution to Z _1-loop arising from tensor, vector, and U (1) gauge fluctuations. The analysis is based on the spectrum of a generalized Lichnerowicz operator governing linearized perturbations on the near-horizon geometry of the extremal solution, including its deformation by the coupling α . In the canonical ensemble, the low-temperature behavior of the one-loop partition function leads to logarithmic corrections to the entropy of the form log( T / T ₀ ), where the scale T ₀ depends on both the fluctuation sector and the Gauss-Bonnet coupling. These corrections are controlled by the structure of zero modes of the deformed operator and their splitting at small but finite temperature. Our explicit computation yields a universal low-temperature scaling log Z _1-loop ~ 5 log T , where the coefficient arises from the combined contributions of tensor, vector, and U (1) gauge modes, reflecting the corresponding counting of zero modes in each sector.

In the near-horizon region, black holes exhibit an infinite-dimensional symmetry reminiscent of the Bondi-Metzner-Sachs supertranslations. The conserved charges associated with this symmetry can be computed in gravitational theories of arbitrary spacetime dimension and involving curvature terms of any order. In Lovelock theory, for instance, these charges take the form of nested Lagrangian densities corresponding to topological invariants, each weighted by the supertranslation function—thus providing a natural generalization of the Wald entropy formula. In four dimensions, the computation of the supertranslation charge reduces to the evaluation of the Jackiw-Teitelboim action on the two-dimensional spacelike sections of the event horizon.

In this letter, we explore different aspects of a 3 + 1 strongly coupled superconductor in the presence of an intense magnetic field. In order to study this interesting and highly complicated system, we make use of the holographic correspondence. We construct a gravitational solution incorporating a fully backreacted Maxwell field while treating a charged scalar field as a perturbation propagating on this background. Our work focuses on the implications of intense magnetic fields on superconductivity in the strongly coupled regime, offering insights into the modifications that such a field induces on key aspects of the superconducting phase, particularly near the critical value where the superconducting phase is broken, which has not been explored by previous perturbative methods. Through rigorous numerical analysis of the holographic model, we uncover intriguing effects arising from the interplay between the magnetic field and the superconducting condensate. Published by the American Physical Society 2025

We study the interplay between higher-curvature terms and the backreaction of quantum fluctuations in three-dimensional massive gravity in asymptotically (anti–)de Sitter space. We focus on the theory at the special point of the parameter space where the two maximally symmetric vacua coincide. In the case of positive cosmological constant, this corresponds to the partially massless point, at which the classical theory admits de Sitter black holes and exhibits an extra conformal symmetry at linear level. We explicitly find the quantum corrected black hole geometry in the semiclassical approximation and show that it induces a relaxation of the standard asymptotic conditions. Nonetheless, the new asymptotic behavior is still preserved by an infinite-dimensional algebra, which, in addition to Virasoro, contains logarithmic supertranslations. Finally, we show that all the results we obtain for the quadratic massive gravity theory can be extended to theories including cubic and quartic terms in the curvature. Published by the American Physical Society 2024

We consider string probes in a traversable wormhole geometry that connects two locally AdS₅ asymptotic regions. Holographically, this describes two interacting copies of a 4-dimensional gauge theory. We consider string configurations whose endpoints are located either in the same boundary or in the two different boundaries of the wormhole. A string with both endpoints in the same boundary is dual to a quark-antiquark pair charged under the same gauge field, while a string extending through the wormhole describes a pair of colored particles charged under two different gauge fields. When one considers a quark-antiquark pair in each boundary, the system undergoes a phase transition: while for small separation each pair of charges exhibits Coulomb interaction, for large separation the charges in different field theories pair up. This behavior had previously been observed in other geometric realizations such as locally AdS₅ wormhole solutions with hyperbolic throats. The geometries we consider here, in contrast, are stable thin-shell wormholes with flat codimension-one hypersurfaces at fixed radial coordinate. They appear as electrovacuum solutions of higher-curvature gravity theories coupled to Abelian gauge fields. The presence of the thin-shells produces a refraction of the string configurations in the bulk, leading to the presence of cusps in the phase space diagram. We discuss these and other features of the phase diagram, including the analogies and difference with other wormhole solutions considered in related contexts.