All-electrical operation of a spin qubit coupled to a high-Q resonator

TL;DR

This paper demonstrates all-electrical control of a silicon hole spin qubit coupled to a high-Q superconducting resonator, addressing crosstalk issues and showing that high coherence times are maintained, advancing scalable quantum computing.

Contribution

It introduces a method to mitigate tank circuit ringup effects during all-electrical spin control in silicon qubits, ensuring high coherence and readout fidelity.

Findings

Control pulse engineering reduces tank ringup effects

Spin coherence time remains unaffected by high-Q resonator coupling

Demonstrates scalable all-electrical spin qubit operation in silicon

Abstract

Building a practical quantum processor involves integrating millions of physical qubits along with the necessary components for individual qubit manipulation and readout. Arrays of gated silicon spins offer a promising route toward achieving this goal. Optimized radio frequency resonators with high internal quality factor are based on superconducting inductors and enable fast spin readout. All-electrical spin control and gate-dispersive readout remove the need for additional device components and simplify scaling. However, superconducting high-Q tank circuits are susceptible to crosstalk induced ringup from electrical qubit control pulses, which causes fluctuations of the quantum dot potential and is suspected to degrade qubit performance. Here, we report on the coherent and all-electrical control of a hole spin qubit at 1.5K, integrated into a silicon fin field-effect transistor and connected to a niobium nitride nanowire inductor gate-sensor. Our experiments show that qubit control pulses with their broad range of higher harmonics ring up the tank when the control pulse spectrum overlaps with the tank resonance. This can cause a reduction of the readout visibility if the tank ringing amplitude exceeds the excited state splitting of the quantum dot, lifting Pauli spin blockade and thus leading to state preparation and measurement errors. We demonstrate how to circumvent these effects by engineering control pulses around the tank resonances. Importantly, we find that the ringup does not limit the spin coherence time, indicating that efficient high-Q resonators in gate-sensing are compatible with all-electrical spin control.