Dephasing of qubits by the Schr\"odinger cat

TL;DR

This paper investigates how a qubit's dephasing behavior is affected when coupled to a bosonic bath initially prepared in a Schr"odinger cat state, revealing dependence on initial conditions for purity, coherence, and entanglement.

Contribution

It demonstrates the impact of initial Schr"odinger cat states on qubit dephasing and entanglement evolution, highlighting dependence on initial conditions.

Findings

Dephasing dynamics depend on the initial Schr"odinger cat state.

Purity and coherence evolution vary with initial bath state.

Entanglement evolution is influenced by initial conditions.

Abstract

We study the dephasing of a single qubit coupled to a bosonic bath. In particular, we investigate the case when the bath is initially prepared in a pure state known as the Schr\"odinger cat. In clear contradistinction to the time-evolution of an initial coherent state, the time evolutions of the purity and the coherence factor now depend on the particular choice of the Schr\"odinger cat state. We also demonstrate that the evolution of the entanglement of a two--qubit system depends on the initial conditions in a similar way.