Recovery of information from black hole radiation by considering stimulated emission

TL;DR

This paper demonstrates that stimulated emission in black hole radiation can carry information about the initial state, offering a potential resolution to the black hole information loss paradox by showing information recovery is possible.

Contribution

It introduces a method to recover information from black hole radiation via stimulated emission, highlighting the nonlocal behavior and calculating the information gain for non-vacuum initial states.

Findings

Information recovered increases with initial particle number r

Over 30% information recovery for r=1000

Final state entropy is compared to thermal state entropy

Abstract

We deal with the black hole information loss paradox by showing that the stimulated emission component of the black hole radiation contains information about the initial state of the system. The nonlocal behaviour that allows the recovery of information about the matter that falls behind the horizon appears in a natural way. We calculate the expectation value and probability distribution of particles at ${\cal J}^+$ for a non-vacuum initial state. The entropy of the final state is compared to that of a thermal state with the same energy per mode. We find that the information recovered about the initial state increases with the number $r$ of the initially incoming particles, reaching for example over 30\% for $r = 1000$. We point out that recovering information about the initial state, nevertheless, does not automatically imply the purity of the final state.