Tunable capacitor for superconducting qubits using an InAs/InGaAs heterostructure

Adoption of fast, parametric coupling elements has improved the performance of superconducting qubits, enabling recent demonstrations of quantum advantage in randomized sampling problems. The development of low loss, high contrast couplers is critical for scaling up these systems. We present a blueprint for a gate-tunable coupler realized with a two-dimensional electron gas in an InAs/InGaAs heterostructure. Rigorous numerical simulations of the semiconductor and high frequency electromagnetic behavior of the coupler and microwave circuitry yield an on/off ratio of more than one order of magnitude. We give an estimate of the dielectric-limited loss from the inclusion of the coupler in a two qubit system, with coupler coherences ranging from a few to tens of microseconds.

Automated summary

The adoption of fast, parametric coupling elements has improved the performance of superconducting qubits, leading to recent demonstrations of quantum advantage in randomized sampling problems. The development of low loss, high contrast couplers is crucial for scaling up these systems. This study presents a blueprint for a gate-tunable coupler realized with a two-dimensional electron gas in an InAs/InGaAs heterostructure, showing promising results in terms of on/off ratio and dielectric-limited loss.