Rashba realization: Raman with RF

TL;DR

This paper proposes a method to realize Rashba spin-orbit coupling in alkali atoms using far-detuned Raman lasers, enabling low inelastic losses and tunable energy gaps by adjusting laser polarizations.

Contribution

It introduces a ground-state Rashba coupling scheme in alkali atoms that minimizes inelastic processes and allows continuous control of the energy gap via laser polarization adjustments.

Findings

Rashba coupling achieved in the ground state manifold of alkali atoms.

Energy gap can be tuned by modifying laser polarizations.

The scheme suppresses spontaneous emission and links hyperfine states via Raman processes.

Abstract

We theoretically explore a Rashba spin-orbit coupling scheme which operates entirely in the absolute ground state manifold of an alkali atom, thereby minimizing all inelastic processes. An energy gap between ground eigenstates of the proposed coupling can be continuously opened or closed by modifying laser polarizations. Our technique uses far-detuned "Raman" laser coupling to create the Rashba potential, which has the benefit of low spontaneous emission rates. At these detunings, the Raman matrix elements that link $m_F$ magnetic sublevel quantum numbers separated by two are also suppressed. These matrix elements are necessary to produce the Rashba Hamiltonian within a single total angular momentum $f$ manifold. However, the far-detuned Raman couplings can link the three XYZ states familiar to quantum chemistry, which possess the necessary connectivity to realize the Rashba potential. We show that these XYZ states are essentially the hyperfine spin eigenstates of $^{87}\text{Rb}$ dressed by a strong radio-frequency magnetic field.