Micro-magnets for coherent control of spin-charge qubit in lateral quantum dots

TL;DR

This paper presents a lateral quantum dot design utilizing integrated micro-magnets for fast, coherent electrical control of spin-charge qubits, achieving sub-100 ns gate operations with high fidelity.

Contribution

It introduces a novel quantum dot setup with integrated micro-magnets enabling voltage-controlled single qubit gates considering stray magnetic fields.

Findings

Sub-100 ns $$ pulse durations are achievable.

Gate fidelity depends on device parameters.

Coherence time of 4 ms in GaAs supports fast operations.

Abstract

A lateral quantum dot design for coherent electrical manipulation of a two-level spin-charge system is presented. Two micron-size permanent magnets integrated to high-frequency electrodes produce a static slanting magnetic field suitable for voltage controlled single qubit gate operations. Stray field deviation from the slanting form is taken into account in the Hamiltonian describing the two-level system, which involves hybridization of a single electron spin to the quantum dot's orbitals. Operation speed and gate fidelity are related to device parameters. Sub 100 ns $\pi$ pulse duration can be achieved with lattice fluctuations coherence time of 4 ms for GaAs.