Cold atoms near superconductors: Atomic spin coherence beyond the Johnson noise limit

TL;DR

This study demonstrates that atomic spin coherence near superconducting niobium surfaces exceeds the Johnson noise limit, indicating suppressed magnetic noise and enabling advanced hybrid quantum systems.

Contribution

It provides experimental evidence of suppressed magnetic near field noise near superconductors, surpassing previous Johnson noise limits for atomic coherence.

Findings

Atomic spin coherence times are longer near superconductors than near normal metals.

Magnetic near field noise is strongly suppressed near superconducting surfaces.

Potential for developing hybrid quantum systems with enhanced coherence.

Abstract

We report on the measurement of atomic spin coherence near the surface of a superconducting niobium wire. As compared to normal conducting metal surfaces, the atomic spin coherence is maintained for time periods beyond the Johnson noise limit. The result provides experimental evidence that magnetic near field noise near the superconductor is strongly suppressed. Such long atomic spin coherence times near superconductors open the way towards the development of coherently coupled cold atom / solid state hybrid quantum systems with potential applications in quantum information processing and precision force sensing.