Hawking radiation as tunneling from charged black holes in 0A string theory

TL;DR

This paper investigates Hawking radiation as a tunneling process from charged black holes in 2D dilaton gravity derived from type 0A string theory, deriving temperature, entropy, and analyzing thermodynamic stability and phase transitions.

Contribution

It applies null-geodesic and Hamilton-Jacobi methods to compute Hawking temperature and entropy for 0A black holes, including back reaction effects, and studies their thermodynamic stability.

Findings

Correct Hawking temperature including back reaction effects.

0A black holes are thermodynamically stable in fixed-charge ensemble.

No phase transition occurs in fixed-charge ensemble; phase transition potential discussed.

Abstract

There has been much work on explaining Hawking radiation as a quantum tunneling process through horizons. Basically, this intuitive picture requires the calculation of the imaginary part of the action for outgoing particle. And two ways are known for achieving this goal: the null-geodesic method and the Hamilton-Jacobi method. We apply these methods to the charged black holes in 2D dilaton gravity which is originated from the low energy effective theory of type 0A string theory. We derive the correct Hawking temperature of the black holes including the effect of the back reaction of the radiation, and obtain the entropy by using the 1st law of black hole thermodynamics. For fixed-charge ensemble, the 0A black holes are free of phase transition and thermodynamically stable regardless of mass-charge ratio. We show this by interpreting the back reaction term as the inverse of the heat capacity of the black holes. Finally, the possibility of the phase transition in the fixed-potential ensemble is discussed.