Spin entanglement induced by spin-orbit interactions in coupled quantum dots

TL;DR

This paper demonstrates how spin-orbit interactions in coupled quantum dots can be used to generate spin entanglement and implement two-qubit gates, with potential applications in quantum information processing.

Contribution

It introduces a theoretical model linking spin-orbit coupling in quantum dots to entanglement and quantum gate operations, expanding understanding of spin-based quantum computing.

Findings

Spin-orbit coupling enables spin entanglement in coupled quantum dots.

Orbital degrees of freedom act as a quantum data bus for information exchange.

A nontrivial two-qubit logic gate is realized through this mechanism.

Abstract

We theoretically explore the possibility of creating spin quantum entanglement in a system of two electrons confined respectively in two vertically coupled quantum dots in the presence of Rashba type spin-orbit coupling. We find that the system can be described by a generalized Jaynes - Cummings model of two modes bosons interacting with two spins. The lower excitation states of this model are calculated to reveal the underlying physics of the far infrared absorption spectra. The analytic perturbation approach shows that an effective transverse coupling of spins can be obtained by eliminating the orbital degrees of freedom in the large detuning limit. Here, the orbital degrees of freedom of the two electrons, which are described by two modes of bosons, serve as a quantized data bus to exchange the quantum information between two electrons. Then a nontrivial two-qubit logic gate is realized and spin entanglement between the two electrons is created by virtue of spin-orbit coupling.