Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields

Abstract

In the endeavour to make quantum computers a reality, integrated superconducting circuits have become a promising architecture. A major challene 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 T1. 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 average qubit T1-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.

Escaping Detrimental Interactions with Microwave-Dressed Transmon Qubits

“…By effectively tuning the qubit away from the TLS modes with the Stark drive, the qubit relaxation time is improved. [32] For the Ramsey dephasing time 𝑇 * 2 , there appears only a slight degradation, which may be attributed to the amplitude noise of the Stark drive. [33,34] In any case, we can conclude that the coherence times are not much changed by the applied Stark drive.…”