Geometric phases in semiconductor spin qubits: Manipulations and decoherence

TL;DR

This paper explores how geometric phases affect spin qubits in quantum dots, highlighting control methods and decoherence mechanisms due to electric field fluctuations, with implications for quantum computing stability.

Contribution

It analyzes the dual role of electric fields in manipulating and decohering spin qubits via geometric phases, considering both control techniques and noise-induced relaxation.

Findings

Electric fields enable coherent spin manipulation through geometric phases.

Fluctuating electric fields cause spin relaxation and dephasing.

Decay rates are estimated for phonon and electron noise sources.

Abstract

We describe the effect of geometric phases induced by either classical or quantum electric fields acting on single electron spins in quantum dots in the presence of spin-orbit coupling. On one hand, applied electric fields can be used to control the geometric phases, which allows performing quantum coherent spin manipulations without using high-frequency magnetic fields. On the other hand, fluctuating fields induce random geometric phases that lead to spin relaxation and dephasing, thus limiting the use of such spins as qubits. We estimate the decay rates due to piezoelectric phonons and conduction electrons in the circuit, both representing dominant electric noise sources with characteristically differing power spectra.