Resonantly driven singlet-triplet spin qubit in silicon

TL;DR

This paper demonstrates a high-fidelity, resonantly driven singlet-triplet spin qubit in silicon with long coherence times, achieved through symmetric operation and magnetic field gradients, advancing quantum computing capabilities.

Contribution

The work introduces a resonantly driven singlet-triplet qubit in silicon with record single-gate fidelity and long coherence times, utilizing symmetric operation and magnetic field gradients.

Findings

T2* exceeding 1 microsecond due to nuclear spin dephasing

99.6% single gate fidelity achieved in benchmarking

Long coherence times enabled by symmetric operation and magnetic field gradient

Abstract

We report implementation of a resonantly driven singlet-triplet spin qubit in silicon. The qubit is defined by the two-electron anti-parallel spin states and universal quantum control is provided through a resonant drive of the exchange interaction at the qubit frequency. The qubit exhibits long $T_2^*$ exceeding 1 $\mu$s that is limited by dephasing due to the $^{29}$Si nuclei rather than charge noise thanks to the symmetric operation and a large micro-magnet Zeeman field gradient. The randomized benchmarking shows 99.6 % single gate fidelity which is the highest reported for singlet-triplet qubits.