Extending the validity range of quantum optical master equations

TL;DR

This paper derives and compares master equations for a two-level atom under various Hamiltonians without common approximations, revealing significant differences in predicted photon emission rates and confirming the accuracy of the rotating wave Hamiltonian.

Contribution

It introduces a derivation of master equations for multiple Hamiltonians without rotating wave and Markovian approximations, highlighting their physical differences.

Findings

Minimal coupling and multipolar Hamiltonians predict high stationary photon emission rates.

Rotating wave Hamiltonian provides the most accurate component representation.

Differences in master equations impact experimental predictions for quantum dots and diamond color centers.

Abstract

This paper derives master equations for an atomic two-level system for a large set of unitarily equivalent Hamiltonians without employing the rotating wave and certain Markovian approximations. Each Hamiltonian refers to physically different components as representing the "atom" and as representing the "field" and hence results in a different master equation, when assuming a photon-absorbing environment. It is shown that the master equations associated with the minimal coupling and the multipolar Hamiltonians predict enormous stationary state narrowband photon emission rates, even in the absence of external driving, for current experiments with single quantum dots and colour centers in diamond. These seem to confirm that the rotating wave Hamiltonian identifies the components of the atom-field system most accurately.