Suppression of dephasing by qubit motion in superconducting circuits

TL;DR

This paper introduces a protocol that uses qubit motion to suppress dephasing caused by low-frequency noise in superconducting circuits, enhancing coherence times and providing a tool to analyze noise correlations.

Contribution

The paper proposes and experimentally demonstrates a qubit motion protocol that reduces dephasing and measures noise correlations in superconducting qubits.

Findings

Qubit motion increases dephasing time as √n for uncorrelated noise.

The protocol is effective with only nearest-neighbor coupling.

Experimental validation with up to three superconducting qubits.

Abstract

We suggest and demonstrate a protocol which suppresses dephasing due to the low-frequency noise by qubit motion, i.e., transfer of the logical qubit of information in a system of $n \geq 2$ physical qubits. The protocol requires only the nearest-neighbor coupling and is applicable to different qubit structures. We further analyze its effectiveness against noises with arbitrary correlations. Our analysis, together with experiments using up to three superconducting qubits, shows that for the realistic uncorrelated noises, qubit motion increases the dephasing time of the logical qubit as $\sqrt{n}$. In general, the protocol provides a diagnostic tool to measure the noise correlations.