Spin rotations induced by electron running on closed trajectories in gated semiconductor nanodevices

TL;DR

This paper proposes a semiconductor nanodevice that performs single-electron spin rotations via closed-loop trajectories, enabling quantum gates like NOT, phase-flip, and Hadamard without microwave radiation.

Contribution

It introduces a novel device design utilizing self-focusing and Rashba spin-orbit coupling for spin manipulation in quantum computing.

Findings

Successfully demonstrates NOT, phase-flip, and Hadamard gates.

Operates with low constant voltages, no microwave radiation needed.

Uses self-focusing effect for compact electron wave packets.

Abstract

A design for a quantum gate performing transformations of a single electron spin is presented. The spin rotations are performed by the electron going around the closed loops in a gated semiconductor device. We demonstrate the operation of NOT, phase-flip and Hadamard quantum gates, i.e. the single-qubit gates which are most commonly used in the algorithms. The proposed devices employ the self-focusing effect for the electron wave packet interacting with the electron gas on the electrodes and the Rashba spin-orbit coupling. Due to the self-focusing effect the electron moves in a compact wave packet. The spin-orbit coupling translates the spatial motion of the electron into the rotations of the spin. The device does not require microwave radiation and operates using low constant voltages. It is therefore suitable for selective single-spin rotations in larger registers.