Paradox No More: How Stimulated Emission of Radiation Preserves Information Absorbed by Black Holes

TL;DR

This paper demonstrates that including stimulated emission in black hole radiation calculations resolves the information loss paradox, showing that information absorbed by black holes can be fully recovered from emitted radiation.

Contribution

It reveals that Hawking's original derivation overlooked stimulated emission, and incorporating it restores the classical information transmission capacity of black holes.

Findings

Stimulated emission is essential in black hole radiation.

Black holes can transmit and recover classical information.

Information loss paradox is resolved by stimulated emission.

Abstract

Black holes have been implicated in two paradoxes that involve apparently non-unitary dynamics. According to Hawking's theory, information that is absorbed by a black hole is destroyed, and the originally pure state of a black hole is converted to a mixed state upon complete evaporation. Here we address one of the two, namely the apparent loss of (classical) information when it crosses the event horizon. We show that this paradox is due to a mistake in Hawking's original derivation: he ignored the contribution of the stimulated emission of radiation that according to Einstein's theory of blackbody radiance must accompany the spontaneous emission (the Hawking radiation). Resurrecting the contribution of stimulated emission makes it possible to calculate the (positive) classical information transmission capacity of black holes, which implies that information is fully recoverable from the radiation outside the black hole horizon.