Complementing the transmon by integrating a geometric shunt inductor

TL;DR

This paper introduces a superconducting qubit design with a geometric shunt inductor that suppresses unwanted interactions and enables fast two-qubit gates, promising scalable quantum computing with low errors.

Contribution

It presents a novel transmon qubit with a geometric inductor, demonstrating suppressed ZZ interactions and fast gates, advancing scalable superconducting qubit architectures.

Findings

Suppressed ZZ interaction at flux sweet spot.

Achieved fast two-qubit gates via sideband transitions.

Potential for large, low-error qubit lattices.

Abstract

We realize a single-Josephson-junction transmon qubit shunted by a simple geometric inductor. We couple it capacitively to a conventional transmon and show that the ZZ interaction between the two qubits is completely suppressed when they are flux-biased to have opposite-sign anharmonicities. Away from the flux sweet spot of the inductively-shunted transmon, we demonstrate fast two-qubit interactions using first-order sideband transitions. The simplicity of this two-qubit-species circuit makes it promising for building large lattices of superconducting qubits with low coherent error and a rich gate set.