Non-Markovian qubit dynamics induced by Coulomb crystals

TL;DR

This paper explores how Coulomb crystals exhibit non-Markovian qubit dynamics, revealing information back-flow related to phase transitions and linking it to Ramsey fringe visibility.

Contribution

It demonstrates the connection between non-Markovian dynamics, phase transitions, and Ramsey fringe visibility in Coulomb crystal systems.

Findings

Back-flow of information signals phase transition proximity.

Non-Markovian behavior varies with dynamical features of the chain.

Exact link established between information back-flow and Ramsey fringe visibility.

Abstract

We investigate the back-flow of information in a system with a second-order structural phase transition, namely a quasi one-dimensional Coulomb crystal. Using standard Ramsey interferometry which couples a target ion (the system) to the rest of the chain (a phononic environment), we study the non-Markovian character of the resulting open system dynamics. We study two different time-scales and show that the back-flow of information pinpoints both the phase transition and different dynamical features of the chain as it approaches criticality. We also establish an exact link between the back-flow of information and the Ramsey fringe visibility.