Pulsed reset protocol for fixed-frequency superconducting qubits

TL;DR

This paper introduces a pulsed reset protocol for superconducting qubits that efficiently reduces excited state populations, enabling faster quantum experiments and improved error correction readiness.

Contribution

A simple two-pulse reset protocol for fixed-frequency superconducting qubits that significantly suppresses excited state populations.

Findings

Remaining excited state population reduced to 2.2%

Enables faster quantum experiment cycles

Improves qubit initialization for error correction

Abstract

Improving coherence times of quantum bits is a fundamental challenge in the field of quantum computing. With long-lived qubits it becomes, however, inefficient to wait until the qubits have relaxed to their ground state after completion of an experiment. Moreover, for error-correction schemes it is import to rapidly re-initialize ancilla parity-check qubits. We present a simple pulsed qubit reset protocol based on a two-pulse sequence. A first pulse transfers the excited state population to a higher excited qubit state and a second pulse into a lossy environment provided by a low-Q transmission line resonator, which is also used for qubit readout. We show that the remaining excited state population can be suppressed to $2.2\pm0.8\%$ and utilize the pulsed reset protocol to carry out experiments at enhanced rates.