Hawking temperature and the bound on greybody factors in $D = 4$ double field theory

TL;DR

This paper analyzes Hawking radiation in four-dimensional double field theory, deriving temperature expressions, exploring limits, and establishing bounds on greybody factors for specific solutions like Schwarzschild and F-JNW.

Contribution

It provides the first derivation of Hawking temperature and bounds on greybody factors for spherical solutions in four-dimensional double field theory.

Findings

Hawking temperature expressions are derived for these solutions.

Only Schwarzschild and F-JNW solutions emit Hawking radiation.

A lower bound on greybody factors is established, showing monotonic increase with certain parameters.

Abstract

We investigate the basic properties of Hawking radiation for spherical solutions in $D = 4$ double field theory. We give the expression of the Hawking temperature for the solution and then discuss the results of various limits. We find that for all these limits only Schwarzschild solution and F-JNW solution can generate Hawking radiation. Moreover, we obtain the lower bound on greybody factors $\sigma_l(\omega)$ for the spherical solutions in $D = 4$ double field theory. In particular, we calculate the bound on greybody factors $\sigma_l(\omega)$ for F-JNW solution. For F-JNW solution, $\sigma_l(\omega)$ monotonically increases with the increase of $a(b)$ for fixed $b(a)$.