Microscopic origin of black hole reentrant phase transitions

Abstract

Understanding the microscopic behavior of the black hole ingredients has been one of the important challenges in black hole physics during the past decades. In order to shed some light on the microscopic structure of black holes, in this paper, we explore a recently observed phenomenon for black holes namely reentrant phase transition, by employing the Ruppeiner geometry. Interestingly enough, we observe two properties for the phase behavior of small black holes that leads to reentrant phase transition. They are correlated and they are of the interaction type. For the range of pressure in which the system underlies reentrant phase transition, it transits from the large black holes phase to the small one which possesses higher correlation than the other ranges of pressures. On the other hand, the type of interaction between small black holes near the large/small transition line differs for usual and reentrant phase transitions. Indeed, for the usual case, the dominant interaction is repulsive whereas for the reentrant case we encounter an attractive interaction. We show that in the reentrant phase transition case, the small black holes behave like a bosonic gas whereas in the usual phase transition case, they behave like a quantum anyon gas.

λ Phase Transition in Horava Gravity

“…This kind of black hole phase transitions have attracted much attention (See the recent review papers [16,17]). Besides, this semiclassical method of analogue is generalized to study the microscopic structure of black holes, and sheds some light on the black hole molecules [18] and microscopic origin of the black hole reentrant phase transition [19]. The study is also extended to the quantum statistic viewpoint, as the superfluid black holes are reported recently [20].…”

Ruppeiner geometry, phase transitions, and the microstructure of charged AdS black holes

“…This yielded the first insight into black hole microstructure. This approach has since been generalized to other black hole systems [50][51][52][53][54][55][56][57][58].…”

Microscopic explanation for black hole phase transitions via Ruppeiner geometry: Two competing factors–the temperature and repulsive interaction among BH molecules

“…In Ref. [46], by comparing the behaviors of R versus the temperature T for Born-Infeld-AdS BHs and singly-spinning Kerr-AdS BHs, the authors found that two properties are responsible for the appearance of RPTs. One is that, in cases with RPT, R < 0 for the SBH near the transition line meaning attractive interaction between the possible BH molecules, while in cases without RPT, R > 0 meaning repulsive interaction.…”

“…Different from the standard definition of the Ruppeiner metric, which is defined on the (M, Q)-space as done in Ref. [46] (see also related work), we define the metric instead on the (M, P )-space as Q is fixed in our cases. By calculating the Ruppeiner invariant R along the co-existing lines, we find that the various phase transitions may be qualitatively well explained as a result of two competing factors: the first one is the low-temperature effect which tends to freeze the BH molecules and thus shrink the BH and the second one is the repulsive interaction between the BH molecules which, on the contrary, tends to expand the BH.…”