First-order sideband transitions with flux-driven asymmetric transmon qubits

TL;DR

This paper demonstrates rapid first-order sideband transitions in a flux-driven asymmetric transmon qubit coupled to a superconducting resonator, enabling efficient quantum state exchange at high rates.

Contribution

It introduces a novel flux-driven method for achieving fast first-order sideband transitions using an asymmetric transmon qubit with a linear energy band segment.

Findings

Achieved sideband transition rates up to 85 MHz.

Demonstrated control of qubit-resonator interactions via flux modulation.

Validated the effectiveness of asymmetry in transmon design for quantum operations.

Abstract

We demonstrate rapid, first-order sideband transitions between a superconducting resonator and a frequency-modulated transmon qubit. The qubit contains a substantial asymmetry between its Josephson junctions leading to a linear portion of the energy band near the resonator frequency. The sideband transitions are driven with a magnetic flux signal of a few hundred MHz coupled to the qubit. This modulates the qubit splitting at a frequency near the detuning between the dressed qubit and resonator frequencies, leading to rates up to 85 MHz for exchanging quanta between the qubit and resonator.