Decoherence and fidelity enhancement during shuttling of entangled spin qubits

TL;DR

This paper investigates how complex noise correlations affect the coherence and fidelity of entangled spin qubits during shuttling, proposing encoding strategies to enhance quantum information transfer.

Contribution

It introduces a trajectory-based analysis of noise correlations and demonstrates how encoding entangled spins improves shuttling fidelity under realistic conditions.

Findings

Correlations in noise significantly influence decoherence during shuttling.

Encoding logical qubits in two entangled spins enhances fidelity.

High fidelity can be maintained even with slow shuttling by exploiting these correlations.

Abstract

Shuttling of spin qubits between different locations is a key element in many prospective semiconductor systems for quantum information processing, but the shuttled qubits should be protected from decoherence created by time- and space-dependent noises. Since the paths of different spin qubits are interrelated, the noises acting on the shuttled spins exhibit complex and unusual correlations. We appraise the role of these correlations using the concept of trajectories on random sheets, and demonstrate that they can drastically affect efficiency of the coherence protection. These correlations can also be exploited to enhance the shuttling fidelity, and we show that by encoding logical qubit in a state of two consequtively shuttled entangled spins, high fidelity can be achieved even for very slow shuttling. We identify the conditions favoring this encoding, and quantify improvement in the shuttling fidelity in comparison with the single-spin shuttling.