Multi-Purpose Architecture for Fast Reset and Protective Readout of Superconducting Qubits

TL;DR

This paper introduces a multi-purpose superconducting qubit architecture enabling rapid reset and environmental protection, enhancing quantum control and measurement efficiency with demonstrated reset times as low as 100 ns.

Contribution

The authors present a novel on-chip diplexer-based design that allows simultaneous fast qubit reset and protection during control and readout, improving upon existing dissipation engineering methods.

Findings

Reset a transmon qubit in 100 ns with 2.7% residual population

Achieve reset times potentially as short as 27 ns using coherent population inversion

Extend reset technique to the second excited state of the qubit

Abstract

The ability to fast reset a qubit state is crucial for quantum information processing. However, to actively reset a qubit requires engineering a pathway to interact with a dissipative bath, which often comes with the cost of reduced qubit protection from the environment. Here, we present a novel multi-purpose architecture that enables fast reset and protection of superconducting qubits during control and readout. In our design, two on-chip diplexers are connected by two transmission lines. The high-pass branch provides a flat passband for convenient allocation of readout resonators above the qubit frequencies, which is preferred for reducing measurement-induced state transitions. In the low-pass branch, we leverage a standing-wave mode below the maximum qubit frequency for a rapid reset. The qubits are located in the common stopband to inhibit dissipation during coherent operations. We demonstrate resetting a transmon qubit from its first excited state to the ground state in 100 ns, achieving a residual population of 2.7%. The reset time may be further shortened to 27 ns by exploiting the coherent population inversion effect. We further extend the technique to resetting the qubit from its second excited state. Our approach promises scalable implementation of fast reset and qubit protection during control and readout, adding to the toolbox of dissipation engineering.