Addressing spins at the clock transitions with a frequency- and bandwidth-tunable superconducting resonator

TL;DR

This paper presents a superconducting resonator with tunable frequency and bandwidth, enabling enhanced control of solid-state spin ensembles for quantum memory with long coherence times.

Contribution

It introduces a superconducting resonator with dynamic frequency and bandwidth tuning capabilities, addressing spins at their clock transition for improved quantum memory performance.

Findings

Achieved a Hahn-echo coherence time of 450 ms at the clock transition.

Demonstrated RF driving of bismuth donor hyperfine transitions.

Showcased dynamic control of resonator bandwidth via parametric coupling.

Abstract

Solid-state spin ensembles addressed via superconducting circuits are promising candidates for quantum memory applications, offering multimodal storage capability and second-long coherence times at their clock transition. Implementing practical memory schemes requires dynamic control over both the resonator frequency and bandwidth. In this letter, we report measurements of a superconducting resonator whose frequency can be tuned by passing a DC current through the high-kinetic-inductance thin film, and whose bandwidth can be tuned by parametric coupling to a low-Q buffer resonator. Using this resonator, we address an ensemble of bismuth donors at their clock transition, measuring a Hahn-echo coherence time of 450 ms. We demonstrate RF driving of the bismuth donor hyperfine transitions, as well as dynamic bandwidth control of the resonator.