Majoranas in Noisy Kitaev Wires

TL;DR

This paper investigates how classical noise affects Majorana edge states in Kitaev wires, revealing conditions under which quantum correlations can persist despite noise, with implications for topological quantum computing.

Contribution

It provides a detailed analysis of the impact of classical noise on Majorana modes in Kitaev wires, highlighting scenarios of noise-induced phase transitions and long-lived quantum correlations.

Findings

Fast noise can induce motional narrowing, preserving quantum correlations.

Certain noise types allow for long-lived Majorana edge correlations.

Topological protection is challenged by time-dependent disorder.

Abstract

Robustness of edge states and non-Abelian excitations of topological states of matter promises quantum memory and quantum processing, which is naturally immune against microscopic imperfections such as static disorder. However, topological properties will not in general protect quantum system from time-dependent disorder or noise. Here we take the example of a network of Kitaev wires with Majorana edge modes storing qubits to investigate the effects of classical noise in the crossover from the quasi-static to the fast fluctuation regime. We present detailed results for the Majorana edge correlations, and fidelity of braiding operations for both global and local noise sources preserving parity symmetry, such as random chemical potentials and phase fluctuations. While in general noise will induce heating and dephasing, we identify examples of long-lived quantum correlations in presence of fast noise due to motional narrowing, where external noise drives the system rapidly between the topological and non-topological phases.