Holographic entanglement entropy and the extended phase structure of STU black holes

TL;DR

This paper investigates the phase structure of 4D STU black holes using extended thermodynamics, revealing Van der Waals-like behavior and showing holographic entanglement entropy captures critical phenomena and phase transitions.

Contribution

It demonstrates that holographic entanglement entropy reflects the extended phase structure of STU black holes, including critical behavior and phase transitions, in a dual quantum field theory context.

Findings

Phase structure resembles Van der Waals gas with first and second order transitions.

Holographic entanglement entropy exhibits transitions at critical points.

Critical exponents for entropy and entanglement entropy coincide.

Abstract

We study the extended thermodynamics, obtained by considering the cosmological constant as a thermodynamic variable, of STU black holes in 4-dimensions in the fixed charge ensemble. The associated phase structure is conjectured to be dual to an RG-flow on the space of field theories. We find that for some charge configurations the phase structure resembles that of a Van der Waals gas: the system exhibits a family of first order phase transitions ending in a second order phase transition at a critical temperature. We calculate the holographic entanglement entropy for several charge configurations and show that for the cases where the gravity background exhibits Van der Waals behavior, the entanglement entropy presents a transition at the same critical temperature. To further characterize the phase transition we calculate appropriate critical exponents and show that they coincide. Thus, the entanglement entropy successfully captures the information of the extended phase structure. Finally, we discuss the physical interpretation of the extended space in terms of the boundary QFT and construct various holographic heat engines dual to STU black holes.