Quantum correlation of an optically controlled quantum system

TL;DR

This paper reviews a diagrammatic technique for accurately calculating quantum correlations in optically controlled quantum systems, extending it to non-coherent photon states and comparing it with existing theories.

Contribution

It introduces an extension of the diagrammatic formalism to non-coherent photon states and compares its accuracy with approximate methods.

Findings

The formalism accurately captures quantum interference effects.

It extends applicability to non-coherent photon controls.

Comparison shows improved precision over existing approximations.

Abstract

A precise time-dependent control of a quantum system relies on an accurate account of the quantum interference among the system, the control and the environment. A diagrammatic technique has been recently developed to precisely calculate this quantum correlation for a fast multimode coherent photon control against slow relaxation, valid for both Markovian and non-Markovian systems. We review this formalism in comparison with the existing approximate theories and extend it to cases with controls by photon state other than the coherent state.