Quantum computation in semiconductor quantum dots of electron-spin asymmetric anisotropic exchange

TL;DR

This paper proposes a method for universal quantum computation using asymmetric anisotropic exchange interactions between electron spins in semiconductor quantum dots, transforming the model into an isotropic form for gate implementation.

Contribution

It introduces a way to control asymmetric anisotropic exchange via local unitary rotations, enabling efficient quantum gate construction in quantum dot systems.

Findings

Asymmetric exchange can be transformed into isotropic exchange for quantum gates.

Local unitary rotations depend on exchange strength and orientation.

Magnetic fields assist in constructing quantum logic gates.

Abstract

The universal quantum computation is obtained when there exists asymmetric anisotropic exchange between electron spins in coupled semiconductor quantum dots. The asymmetric Heisenberg model can be transformed into the isotropic model through the control of two local unitary rotations for the realization of essential quantum gates. The rotations on each qubit are symmetrical and depend on the strength and orientation of asymmetric exchange. The implementation of the axially symmetric local magnetic fields can assist the construction of quantum logic gates in anisotropic coupled quantum dots. This proposal can efficiently use each physical electron spin as a logical qubit in the universal quantum computation.