Hawking-Page phase transition, Page curve and islands in black holes

Abstract: We study the effect of the Hawking-Page phase transition on the Page Curve for the BTZ black hole coupled to two thermal baths and with the inclusion of island. The Page Curve is shown by us when the Hawking-Page phase transition happens. The results show that the Hawking-Page phase transition may happen before the Page time or after the Page time under certain conditions. We also study the holographic entanglement entropy when the Hawking-Page phase transition happens for the BTZ black hole in the gauge/gravity setup and derive a first law of entanglement in the boundary and bulk. If a first law of entanglement thermodynamics is universally true, then we can conjecture that all the information of the black hole will come out at the critical temperature when the Hawking-Page phase transition happens. Furthermore, We further speculate that the effect of the first-order phase transition of black holes on the black hole information is universal. These results mean that black holes information does not have to escape by the radiation, and the first-order phase transition of black holes can also cause information to escape.