Soliton-Black Hole Phase Transitions in the Presence of String Clouds

Abstract

We study soliton-black hole phase transitions in asymptotically AdS planar spacetimes sourced by a cloud of strings. In the planar background, the string cloud exhibits a brush-like configuration, where the strings are aligned parallel to each other and extend along the radial direction. This leads to a stress tensor with nonvanishing components only along the temporal and radial directions. By comparing the Euclidean on-shell actions of the planar black hole and the corresponding AdS soliton under the same boundary conditions, we obtain the free energy difference between the two phases. Our results show that the string cloud parameter significantly modifies the competition between the black hole phase and the soliton phase. In particular, positive and negative values of the string cloud parameter affect the phase structure in different ways, changing the dominance relation between the black hole and soliton configurations.