Quantum information transfer and models for black hole mechanics

TL;DR

This paper explores quantum information transfer mechanisms relevant to black hole physics, categorizing models of black hole evolution and analyzing their implications for information retrieval and thermodynamics.

Contribution

It introduces a classification of quantum information transfer models for black holes, including subspace transfer and other unitary evolutions, highlighting their differences and implications.

Findings

Subspace transfer saturates subadditivity inequality.

Information transfer models can be saturating or non-saturating.

Non-saturating models often have increased energy flux beyond Hawking radiation.

Abstract

General features of information transfer between quantum subsystems, via unitary evolution, are investigated, with applications to the problem of information transfer from a black hole to its surroundings. A particularly direct form of quantum information transfer is "subspace transfer," which can be characterized by saturation of a subadditivity inequality. We also describe more general unitary quantum information transfer, and categorize different models for black hole evolution. Evolution that only creates paired excitations inside/outside the black hole is shown not to extract information, but information-transferring models exist both in the "saturating" and "non-saturating" category. The former more closely capture thermodynamic behavior; the latter generically have enhanced energy flux, beyond that of Hawking.