Coherent Control of a Superconducting Qubit with Dynamically Tunable Qubit-cavity Coupling

TL;DR

This paper demonstrates the dynamic control of a superconducting qubit's coupling to a resonator, enabling precise manipulation and measurement crucial for quantum computing applications.

Contribution

It introduces a method for tunably controlling qubit-cavity coupling in superconducting circuits, allowing for improved qubit isolation and control.

Findings

Qubit-cavity coupling can be tuned off by a factor of over 1500.

Qubit coherence times of 1.6 and 1.9 microseconds were achieved.

Fast flux pulses enable qubit access even in the off state.

Abstract

We demonstrate coherent control and measurement of a superconducting qubit coupled to a superconducting coplanar waveguide resonator with a dynamically tunable qubit-cavity coupling strength. Rabi oscillations are measured for several coupling strengths showing that the qubit transition can be turned off by a factor of more than 1500. We show how the qubit can still be accessed in the off state via fast flux pulses. We perform pulse delay measurements with synchronized fast flux pulses on the device and observe $T_1$ and $T_2$ times of 1.6 and 1.9 $\mu$s, respectively. This work demonstrates how this qubit can be incorporated into quantum computing architectures.