Coherent charge and spin oscillations induced by local quenches in nanowires with spin-orbit coupling

TL;DR

This paper demonstrates that local quenches in nanowires with spin-orbit coupling induce stable, coherent charge and spin oscillations, which can be controlled electrically, offering potential for quantum control applications.

Contribution

It reveals that spin-orbit coupled nanowires exhibit stable coherent oscillations after local quenches, even with weak potentials, and shows how to control spin oscillations electrically.

Findings

Coherent oscillations occur in charge and spin sectors after local quenches.

Weak attractive potentials are sufficient to induce oscillations in SOC nanowires.

Electrical control of spin oscillations is possible via gate voltage quenches.

Abstract

When a local and attractive potential is quenched in a nanowire, the spectrum changes its topology from a purely continuum to a continuum and discrete portion. We show that, under appropriate conditions, this quench leads to stable coherent oscillations in the observables time evolution. In particular, we demonstrate that ballistic nanowires with spin-orbit coupling (SOC) exposed to a uniform magnetic field are especially suitable to observe this effect. Indeed, while in ordinary nanowires the effect occurs only if the strength $U_0$ of the attractive potential is sufficiently strong, even a weak value of $U_0$ is sufficient in SOC nanowires. Furthermore, in these systems coherent oscillations in the spin sector can be generated and controlled electrically by quenching the gate voltage acting on the charge sector. We interpret the origin of this phenomenon, analyze the effect of variation of the chemical potential and the switching time of the quenched attractive potential, and address possible implementation schemes.