Single-Shot Readout and Weak Measurement of a Tin-Vacancy Qubit in Diamond

TL;DR

This paper demonstrates high-fidelity single-shot readout and weak measurement of a tin-vacancy qubit in diamond, advancing quantum network components by improving measurement techniques and understanding measurement-induced decoherence.

Contribution

It introduces a method for single-shot readout of SnV$^-$ spins with high fidelity and explores weak measurement effects, enhancing quantum control in solid-state systems.

Findings

Achieved 87.4% single-shot readout fidelity, improved to 98.5% with multiple readouts.

Showed compatibility of high-fidelity readout with rapid microwave spin control.

Used weak measurement to study measurement-induced dephasing and decoherence.

Abstract

The negatively charged tin-vacancy center in diamond (SnV$^-$) is an emerging platform for building the next generation of long-distance quantum networks. This is due to the SnV$^-$'s favorable optical and spin properties including bright emission, insensitivity to electronic noise, and long spin coherence times at temperatures above 1 Kelvin. Here, we demonstrate measurement of a single SnV$^-$ electronic spin with a single-shot readout fidelity of $87.4\%$, which can be further improved to $98.5\%$ by conditioning on multiple readouts. We show this performance is compatible with rapid microwave spin control, demonstrating that the trade-off between optical readout and spin control inherent to group-IV centers in diamond can be overcome for the SnV$^-$. Finally, we use weak quantum measurement to study measurement induced dephasing; this illuminates the fundamental interplay between measurement and decoherence in quantum mechanics, and makes use of the qubit's spin coherence as a metrological tool. Taken together, these results overcome an important hurdle in the development of the SnV$^-$ based quantum technologies, and in the process, develop techniques and understanding broadly applicable to the study of solid-state quantum emitters.