Corrected Hawking Temperature and Final State of Black Hole Evaporation Under GEVAG Framework

Abstract

In the GEVAG (Generalized Entropy Varying-G) framework, any generalization to horizon entropy leads to a varying gravitational "constant" $G_\text{eff}$ that is a function the horizon area. In this work, it is shown that if we promote $G_\text{eff}$ to be valid in the neighborhood of the horizon, then Hawking temperature consists of two terms, the second of which is related to the variation of $G_\text{eff}$. When applied to the logarithmic correction of the entropy, as is common across various quantum gravity approaches, the first term in the Schwarzschild black hole temperature exactly agrees with that obtained from utilizing generalized uncertainty principle (GUP), while the second term improves on the GUP result by driving the Hawking temperature to zero as the black hole approaches a minimum mass. This resolves the inconsistency in the GUP result concerning a nonzero temperature minimum mass remnant. This work also derives simple general formulas for both the thermodynamic energy and the Bekenstein bound for any correction to the area law under the same assumption that $G_\text{eff}$ can be extended off-shell in the horizon neighborhood. The (generalized) Bekenstein bound can be interpreted as a statement regarding the renormalization group scaling dimension of the entropy functional $f(A)$ and the naturalness of the theory.

Figures (2)

• Figure 1: The Hawking temperature (as a function of $M$) for the fully corrected Hawking temperature under GEVAG, assuming logarithmic correction to the Bekenstein Hawking entropy shown in sold red curve. It goes to zero as $M \to M_\text{min}$. This is compared to the dashed black curve that shows the original Hawking expression which is inversely proportional to the mass, as well as the dotted blue curve for the GUP expression that ends with a finite temperature remnant indicated by the blue dot. In this plot we set $G=c_1=1$ for numerical convenience.
• Figure 2: The Bekenstein constant as a function of the horizon area. Here we take $c_1=1$. In the large $A$ limit it asymptotes from above to the GR value of $2\pi$. When $A=1$, the minimum area, we have $C_B=\pi$.