Robustness of quantum memories based on Majorana zero modes

TL;DR

This paper investigates the robustness of quantum information stored in Majorana zero modes, demonstrating that such information can be preserved for exponentially long times despite various perturbations, including quenching and dephasing.

Contribution

It provides a detailed analysis of how quantum information in Majorana modes remains stable under realistic perturbations, highlighting mechanisms behind their robustness.

Findings

Quantum information survives for exponentially long times with system size.

Majorana modes maintain coherence despite high-frequency perturbations.

Finite temperature effects and particle exchange have limited impact on storage time.

Abstract

We analyze the rate at which quantum information encoded in zero-energy Majorana modes is lost in the presence of perturbations. We show that information can survive for times that scale exponentially with the size of the chain both in the presence of quenching and time-dependent quadratic dephasing perturbations, even when the latter have spectral components above the system's energy gap. The origin of the robust storage, namely the fact that a sudden quench affects in the same way both parity sectors of the original spectrum, is discussed, together with the memory performance at finite temperatures and in the presence of particle exchange with a bath.