Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields

TL;DR

This paper demonstrates that applying DC electric fields can significantly improve the coherence times of superconducting qubits by tuning defect resonances, with potential for in-situ optimization in quantum processors.

Contribution

The study introduces a method to enhance qubit coherence by tuning defects away from resonance using electric fields, improving $T_1$ times by 23%.

Findings

Enhanced qubit $T_1$ time by 23% through electric field tuning.

Demonstrated in-situ coherence optimization potential with local gate electrodes.

Identified defect resonance tuning as a viable approach to reduce decoherence.

Abstract

In the endeavour to make quantum computers a reality, integrated superconducting circuits have become a promising architecture. A major challenge of this approach is decoherence originating from spurious atomic tunneling defects at the interfaces of qubit electrodes, which may resonantly absorb energy from the qubit's oscillating electric field and reduce the qubit's energy relaxation time $T_1$. Here, we show that qubit coherence can be improved by tuning dominating defects away from the qubit resonance using an applied DC-electric field. We demonstrate a method that optimizes the applied field bias and enhances the 30-minute averaged qubit $T_1$ time by 23\%. We also discuss how local gate electrodes can be implemented in superconducting quantum processors to enable simultaneous in-situ coherence optimization of individual qubits.