Spin dynamics in a strongly driven system: very slow Rabi oscillations

TL;DR

This paper investigates how tunneling and spin-orbit coupling influence spin dynamics in a double quantum dot under strong electric fields, revealing slow Rabi oscillations and challenges in achieving full spin flips due to multi-level effects.

Contribution

It demonstrates the crucial role of tunneling in Rabi-like spin transitions and uncovers the slowing down of spin flips in multi-level systems under strong driving fields.

Findings

Tunneling is essential for Rabi-like spin-flip transitions.

Spin flip rate decreases and oscillates with increasing electric field strength.

Full spin flip is difficult in multi-level resonant systems.

Abstract

We consider joint effects of tunneling and spin-orbit coupling on driven by electric field spin dynamics in a double quantum dot with a multi-level resonance scenario. We demonstrate that tunneling plays the crucial role in the formation of the Rabi-like spin-flip transitions. In contrast to the linear behavior for weak electric fields, the spin flip rate becomes much smaller than expected for the two-level model and shows oscillating dependence on the driving field amplitude in stronger fields. In addition, the full spin flip is very difficult to achieve in a multi-level resonant system. These two effects have a similarity with the Zeno effect of slowing down the dynamics of an observable by its measurement. As a result, spin manipulation by electric field becomes much less efficient than expected.