Macroscopic superposition and entanglement for displaced thermal fields induced by a single atom

TL;DR

This paper demonstrates how a cavity field initially in a displaced thermal state can evolve into macroscopic superpositions and entanglement with a two-level atom, providing insights into quantum measurement and decoherence in realistic conditions.

Contribution

It introduces a method for generating macroscopic superpositions and entanglement from thermal states via atom-field interactions, relevant for quantum measurement studies.

Findings

Cavity fields evolve into superpositions of displaced thermal states.

Entanglement between modes can be achieved with thermal states.

Results are relevant for understanding decoherence in quantum systems.

Abstract

We show that a cavity field can evolve from an initial displaced mixed thermal state to a macroscopic superpositions of displaced thermal states via resonant interaction with a two-level atom. As a macroscopic system (meter) is really in a mixed state before coupling with the microscopic system at some temperature, our result is important for studying the quantum measurement problem and decoherence under real conditions. For the two-mode case, entanglement of displaced thermal states between the modes can be obtained.