A Unified Theory of Consequences of Spontaneous Emission in a $\Lambda$ System

TL;DR

This paper presents a comprehensive quantum theory of spontaneous emission effects in a three-level $\Lambda$ system, revealing how different measurement approaches influence electron-photon entanglement and coherence phenomena.

Contribution

It introduces a unified quantum framework for analyzing spontaneous emission consequences in $\Lambda$ systems, extending beyond specific models.

Findings

Different photon measurement strategies lead to varied electron-photon entangled states.

The theory accounts for phenomena like spontaneously generated coherence and two-pathway decay.

The approach is applicable to systems beyond the three-level model.

Abstract

In a $\Lambda$ system with two nearly degenerate ground states and one excited state in an atom or quantum dot, spontaneous radiative decay can lead to a range of phenomena, including electron-photon entanglement, spontaneously generated coherence, and two-pathway decay. We show that a treatment of the radiative decay as a quantum evolution of a single physical system composed of a three-level electron subsystem and photons leads to a range of consequences depending on the electron-photon interaction and the measurement. Different treatments of the emitted photon channel the electron-photon system into a variety of final states. The theory is not restricted to the three-level system.