arXiv subjects

Daniel E. Paraizo

Publications and source records attributed to Daniel E. Paraizo.

4 recordsLinked to original sources

arXiv2026

On Radiative Fluxes and Coulombic Charges in the Balance Law for Black Hole Evaporation

In asymptotically-flat spacetimes, there is a clear distinction between radiative fluxes and Coulombic charges. Using the Wald-Zoupas prescription, we identify the classical radiative flux of a massless scalar field in 3+1 dimensions. In a spherically-symmetric model of black hole evaporation, the balance law yields a Bondi mass correction related to the entanglement entropy of Hawking radiation. The renormalized flux is nonnegative, differs from the Fulling-Davies formula, and coincides with the Ashtekar-Taveras-Varadarajan flux. We discuss implications for 3+1 black hole evaporation.

gr-qc↗

arXiv2026

Thermodynamics of dynamical black holes beyond perturbation theory

The close similarities of the three laws of black hole mechanics, discovered by Bardeen, Carter and Hawking, with the laws of thermodynamics led to the identification of a multiple of the area of the event horizon with entropy. However, developments over the past two decades have shown that this paradigm has some important limitations, especially because of the teleological nature of event horizons. After a brief review of these limitations, we will show that they can be overcome using quasi-local horizons. Specifically, the new first law applies to black holes in general relativity that can be \emph{arbitrarily far from equilibrium} and refers to \emph{finite} changes that occur due to \emph{physical processes} at the horizon. The second law is now a \emph{quantitative} statement that relates the change in the area of a dynamical horizon segment due to fluxes of energy falling into the black hole. Together, they lead one to identify black hole entropy with the area of marginally trapped surfaces in quasi-local horizons, generalizing recent perturbative findings that it should be identified not with the area of the event horizon but with the area of a marginally trapped surface inside it.

gr-qc↗

arXiv2026

Thermodynamics of Black Holes, far from Equilibrium

As in thermodynamics, the celebrated first law of black hole mechanics relates infinitesimal changes in the properties of nearby equilibrium states of black holes (without reference to any physical process that causes the transition). Using dynamical horizon segments (DHSs), we extend the first law to encompass black holes that can be arbitrarily far from equilibrium. It now refers to \emph{finite} changes that occur due to \emph{physical processes}. This extension, together with the generalized second law on DHSs \cite{Ashtekar:2003hk}, naturally lead one to identify entropy of dynamical BHs with the area DHSs.

gr-qc↗

arXiv2026

Minimum lifetime of a black hole

We derive bounds on the lifetime of an evaporating black hole. The bound follows from energy conservation and purification, within the framework of `asymptotically semiclassical spacetimes'. We use the recently derived expression for the Bondi flux of Hawking radiation, together with the expression for the entanglement entropy of Hawking radiation at null infinity, to investigate the purification phase after the last semiclassical ray. We discuss the energy-cost of entanglement purification and we find a lower bound on the purification time of the black hole, which scales as $M_0^4/\hbar^{3/2}$, where $M_0$ is the initial black hole mass. Additionally, motivated by quantum gravity considerations, we include the additional assumption that a Planck mass black hole is metastable. With this assumption, we find that the the purification time is extended to be exponential in the square of the initial black hole mass, i.e. in its initial area. We find that the redshift exponent is negative in this purification phase, which indicates the existence of a white-hole remnant which releases information slowly. We comment on phenomenological implications for primordial black hole remnants.

gr-qc↗