# Influence of excited state decay and dephasing on phonon quantum state preparation

## TL;DR

This paper investigates how decay and dephasing in a two-level quantum system affect the generation and preservation of phonon quantum states, including Schrödinger cat states, using the independent boson model.

## Contribution

It demonstrates how decay and dephasing influence phonon state preparation, highlighting the preservation of quantum properties during decay and the effects of dephasing on interference.

## Key findings

- Decay transforms phonon states into circular phase space distributions.
- Dephasing reduces interference in phonon superpositions.
- Decay preserves quantum properties during transition to ground state.

## Abstract

The coupling between single-photon emitters and phonons opens many possibilities to store and transmit quantum properties. In this paper we apply the independent boson model to describe the coupling between an optically driven two-level system and a discrete phonon mode. Tailored optical driving allows not only to generate coherent phonon states, but also to generate coherent superpositions in the form of Schr\"odinger cat states in the phonon system. We analyze the influence of decay and dephasing of the two-level system on these phonon preparation protocols. We find that the decay transforms the coherent phonon state into a circular distribution in phase space. Although the dephasing between two exciting laser pulses leads to a reduction of the interference ability in the phonon system, the decay conserves it during the transition into the ground state. This allows to store the phonon quantum state properties in the ground state of the single-photon emitter.