Disentanglement of Source and Target and the Laser Quantum State

TL;DR

This paper proposes a criterion for defining laser quantum states as coherent states based on source-target disentanglement, analyzing the effects of environmental monitoring on their quantum state factorization.

Contribution

It introduces a novel criterion for laser state coherence through source-target disentanglement and examines the impact of environmental records on quantum state factorization.

Findings

Source-target density operator factorizes into coherent states when environmental monitoring is ignored.

Complete environmental record leads to an entangled source-target state with fixed total quanta.

Disentanglement criterion helps clarify the quantum nature of laser states.

Abstract

Disentanglement of a laser source from its target qubit is proposed as a criterion establishing the laser quantum state as a coherent state. It is shown that the source-target density operator has a unique factorization in coherent states when the environmental record monitoring laser pump quanta is ignored. The source-target state conditioned upon the complete environmental record is entangled, though, as a state of known total quanta number (source plus target).