Dynamical spin properties of confined Fermi and Bose systems in presence of spin-orbit coupling

TL;DR

This paper investigates how spin-orbit coupling influences the dynamical spin properties of confined Fermi and Bose systems, revealing controllable spin fluctuations, textures, and currents relevant for spintronics and quantum computing.

Contribution

It provides a detailed analysis of spin dynamics with equal Rashba and Dresselhaus couplings, including effects of interactions and confinement, highlighting novel spin textures and current control mechanisms.

Findings

Periodic spin fluctuations can be induced and maintained.

Two-body interactions do not cause decoherence in bosonic dimers.

Repulsive Fermi gases can exhibit tunable standing currents.

Abstract

Due to the recent experimental progress, tunable spin-orbit (SO) interactions represent ideal candidates for the control of polarization and dynamical spin properties in both quantum wells and cold atomic systems. A detailed understanding of spin properties in SO coupled systems is thus a compelling prerequisite for possible novel applications or improvements in the context of spintronics and quantum computers. Here we analyze the case of equal Rashba and Dresselhaus couplings in both homogeneous and laterally confined two-dimensional systems. Starting from the single-particle picture and subsequently introducing two-body interactions we observe that periodic spin fluctuations can be induced and maintained in the system. Through an analytical derivation we show that the two-body interaction does not involve decoherence effects in the bosonic dimer, and, in the repulsive homogeneous Fermi gas it may be even exploited in combination with the SO coupling to induce and tune standing currents. By further studying the effects of a harmonic lateral confinement --a particularly interesting case for Bose condensates-- we evidence the possible appearance of non-trivial {\it spin textures}, whereas the further application of a small Zeeman-type interaction can be exploited to fine-tune the system polarizability.