# Photo-assisted spin transport in double quantum dots with spin-orbit interaction

## TL;DR

This paper explores how spin-orbit interaction influences spin transport in double quantum dots under ac electric fields, revealing dark states, spin filtering, and qubit control mechanisms.

## Contribution

It introduces a model for ac-induced spin dynamics, identifies spin-polarized dark states, and demonstrates tunable spin filtering and qubit operation in quantum dot systems.

## Key findings

- Discovery of ac-induced spin-polarized dark states
- Demonstration of highly tunable spin filtering
- Proposal of resonant flopping-mode qubit operation

## Abstract

We investigate the effect of spin-orbit interaction on the intra- and interdot particle dynamics of a double quantum dot under ac electric fields. The former is modeled as an effective ac magnetic field that produces electric-dipole spin resonance transitions, while the latter is introduced via spin-flip tunneling amplitudes. We observe the appearance of non-trivial spin-polarized dark states, arising from an ac-induced interference between photo-assisted spin-conserving and spin-flip tunneling processes. These dark states can be employed to precisely measure the spin-orbit coupling in quantum dot systems. Furthermore, we show that the interplay between photo-assisted transitions and spin-flip tunneling allows the system to operate as a highly tunable spin filter. Finally, we investigate the operation of the system as a resonant flopping-mode qubit for arbitrary ac voltage amplitudes, allowing for high tunability and enhanced qubit control possibilities.