Noise-compensating pulses for electrostatically controlled silicon spin qubits

TL;DR

This paper evaluates SUPCODE pulses for silicon spin qubits, demonstrating significant error reduction and high fidelity, especially in isotope-enriched silicon, by compensating for Overhauser and charge noise.

Contribution

It adapts and tests SUPCODE pulses for silicon spin qubits, introducing a charge-noise-only variant that improves gate fidelity and speed in isotope-enriched silicon.

Findings

SUPCODE reduces gate error by about an order of magnitude.

In isotope-enriched Si, SUPCODE achieves very high fidelity gates.

Charge-noise-only SUPCODE shortens gate times by 30-50%.

Abstract

We study the performance of SUPCODE---a family of dynamically correcting pulses designed to cancel simultaneously both Overhauser and charge noise for singlet-triplet spin qubits---adapted to silicon devices with electrostatic control. We consider both natural Si and isotope-enriched Si systems, and in each case we investigate the behavior of individual gates under static noise and perform randomized benchmarking to obtain the average gate error under realistic 1/f noise. We find that in most cases SUPCODE pulses offer roughly an order of magnitude reduction in gate error, and especially in the case of isotope-enriched Si, SUPCODE yields gate operations of very high fidelity. We also develop a version of SUPCODE that cancels the charge noise only, "$\delta J$-SUPCODE", which is particularly beneficial for isotope-enriched Si devices where charge noise dominates Overhauser noise, offering a level of error reduction comparable to the original SUPCODE while yielding gate times that are 30% to 50% shorter. Our results show that the SUPCODE noise-compensating pulses provide a fast, simple, and effective approach to error suppression, bringing gate errors well below the quantum error correction threshold in principle.