One-second coherence for a single electron spin coupled to a multi-qubit nuclear-spin environment

TL;DR

This paper demonstrates a coherence time exceeding one second for a single electron spin by tailoring decoupling sequences to its nuclear-spin environment, enabling advanced quantum sensing and multi-qubit registers.

Contribution

It introduces a method to achieve long coherence times by precisely controlling and understanding the nuclear-spin environment of a single electron spin.

Findings

Achieved over one second coherence time for a single electron spin.

Accurately characterized the nuclear-spin environment with seven individual and six coupled carbon-13 spins.

Demonstrated quantum state storage for over a second by avoiding unwanted interactions.

Abstract

Single electron spins coupled to multiple nuclear spins provide promising multi-qubit registers for quantum sensing and quantum networks. The obtainable level of control is determined by how well the electron spin can be selectively coupled to, and decoupled from, the surrounding nuclear spins. Here we realize a coherence time exceeding a second for a single electron spin through decoupling sequences tailored to its microscopic nuclear-spin environment. We first use the electron spin to probe the environment, which is accurately described by seven individual and six pairs of coupled carbon-13 spins. We develop initialization, control and readout of the carbon-13 pairs in order to directly reveal their atomic structure. We then exploit this knowledge to store quantum states for over a second by carefully avoiding unwanted interactions. These results provide a proof-of-principle for quantum sensing of complex multi-spin systems and an opportunity for multi-qubit quantum registers with long coherence times.