Thermodynamic topology of 4D charged AdS black holes with $$F^{\alpha \beta }F^{\gamma \lambda }R_{\alpha \gamma \beta \lambda }$$ coupling
Year: 2026
Type: article
Abstract: We investigate the thermodynamic phase transitions of a four-dimensional charged anti-de Sitter black hole endowed with a non-minimal coupling of the form $$F^{\alpha \beta }F^{\gamma \lambda }R_{\alpha \gamma \beta \lambda }$$ F α β F γ λ R α γ β λ . Using perturbative methods, we derive a consistent black hole solution and analyze its thermodynamics through both conventional equilibrium techniques and a topological defect classification approach. In the canonical ensemble, the system displays van der Waals-like critical behavior, with a swallow-tail structure in the free energy and distinct phase branches. In the grand canonical ensemble, by contrast, the system exhibits a Hawking–Page-like transition, characterized by a single divergence in the heat capacity and the absence of a swallowtail. The topological analysis independently confirms both types of critical behavior: it classifies the canonical ensemble within class $$W^{1+}$$ W 1 + and the grand canonical ensemble within class $$W^{0-}$$ W 0 - . Our results demonstrate that the non-minimal coupling preserves the universal topological classification while allowing ensemble choice to fundamentally alter the phase structure.
Source: The European Physical Journal C
Authors: Mehdi Sadeghi, Faramaz Rahmani
Institution: Ayatollah Boroujerdi University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7162528619