Permanent spin currents in cavity-qubit systems

TL;DR

This paper proposes a method to generate persistent spin currents in cavity-qubit systems by balancing drives and dissipation, enabling scalable and stable current production despite imperfections.

Contribution

It introduces a novel scheme for creating permanent spin currents in cavity-qubit architectures, overcoming limitations of finite lifetime due to dissipation.

Findings

Scheme enables continuous spin currents despite dissipation

Scalable approach for larger systems

Balances drives and dissipation to sustain currents

Abstract

In a recent remarkable experiment [P. Roushan et al., Nature Physics 13, 146 (2017)], a spin current in an architecture of three superconducting qubits was produced during a few microseconds by creating synthetic magnetic fields. The life-time of the current was set by the typical dissipative mechanisms that occur in those systems. We propose a scheme for the generation of permanent currents, even in the presence of such imperfections, and scalable to larger system sizes. It relies on striking a subtle balance between multiple nonequilibrium drives and the dissipation mechanisms, in order to engineer and stimulate chiral excited states which can carry current.