Half-BPS Geometries and Thermodynamics of Free Fermions
Abstract
Solutions of type IIB supergravity which preserve half of the supersymmetries have a dual description in terms of free fermions, as elucidated by the "bubbling AdS" construction of Lin, Lunin and Maldacena. In this paper we study the half-BPS geometry associated with a gas of free fermions in thermodynamic equilibrium obeying the Fermi-Dirac distribution. We consider both regimes of low and high temperature. In the former case, we present a detailed computation of the ADM mass of the supergravity solution and find agreement with the thermal energy of the fermions. The solution has a naked null singularity and, by general arguments, is expected to develop a finite area horizon once stringy corrections are included. By introducing a stretched horizon, we propose a way to match the entropy of the fermions with the entropy of the geometry in the low temperature regime. In the opposite limit of high temperature, the solution resembles a dilute gas of D3 branes. Also in this case the ADM mass of the geometry agrees with the thermal energy of the fermions.
Keywords
Cite
@article{arxiv.hep-th/0512101,
title = {Half-BPS Geometries and Thermodynamics of Free Fermions},
author = {Simone Giombi and Manuela Kulaxizi and Riccardo Ricci and Diego Trancanelli},
journal= {arXiv preprint arXiv:hep-th/0512101},
year = {2010}
}
Comments
37 pages, 2 figures, latex; v2: minor corrections, references added