Verification of stable operation of rapid single flux quantum devices with selective dissipation

TL;DR

This paper experimentally verifies that using frequency-dependent damping in RSFQ circuits maintains stable operation, making them more suitable as classical interfaces for superconducting qubits.

Contribution

It demonstrates the practical application and stability of frequency-dependent damping in full RSFQ circuits, advancing their scalability for quantum computing interfaces.

Findings

Frequency-dependent damping preserves stable operation in RSFQ circuits.

The approach is feasible for scalable RSFQ device integration.

Discussion on realization and optimization issues included.

Abstract

It has been suggested that Rapid Single Flux Quantum (RSFQ) devices could be used as the classical interface of superconducting qubit systems. One problem is that the interface acts as a dissipative environment for a qubit. Recently ways to modify the RSFQ damping to reduce the dissipation have been introduced. One of the solutions is to damp the Josephson junctions by a frequency-dependent linear circuit instead of the plain resistor. The approach has previously been experimentally tested with a simple SFQ comparator. In this paper we perform experiments with a full RSFQ circuit, and thus conclude that in terms of stable operation the approach is applicable for scalable RSFQ circuits. Realisation and optimisation issues are also discussed.