Joule-Thomson expansion of $d$-dimensional charged AdS black holes

TL;DR

This paper explores how the dimensionality of charged AdS black holes influences the Joule-Thomson expansion, analyzing key thermodynamic aspects and revealing that inversion temperature ratios vary with dimension.

Contribution

It provides a detailed analysis of Joule-Thomson expansion in $d$-dimensional charged AdS black holes, including explicit expressions and novel insights into inversion curves and temperature ratios.

Findings

Inversion temperature increases with dimension at low pressure.

The ratio of minimum inversion to critical temperature decreases with dimension.

Isenthalpic curves expand toward higher pressure as dimension increases.

Abstract

Effects of the dimensionality on the Joule-Thomson expansion are discussed in detail by considering the case of $d$-dimensional charged AdS black holes. Specifically, we investigate three important aspects characteristic of the Joule-Thomson expansion. Namely, the Joule-Thomson coefficient, the inversion curves and the isenthalpic curves. We utilize two different approaches to derive the explicit expression of the Joule-Thomson coefficient and show that both approaches are consistent with each other. The divergent point and the zero point of the Joule-Thomson coefficient are discussed. The former is shown to reveal the information of Hawking temperature while the latter is depicted through the so-called inversion curves. Fine structures of the inversion curves are disclosed in the cases $d>4$. At low pressure, the inversion temperature increases with the dimensionality $d$ while at high pressure it decreases with $d$. The ratio between minimum inversion temperature $T_{min}$ and the critical temperature $T_c$ is discussed with its explicit expression obtained for $d>4$. Surprisingly, it is shown that the ratio is not always equal to $1/2$ but decreases with the dimensionality $d$. Moreover, isenthalpic curves of $d>4$ are shown to expand toward higher pressure when the dimensionality $d$ increases.