Adiabatic optical entanglement between electron spins in separate quantum dots

TL;DR

This paper proposes an adiabatic optical method to entangle electron spins in separate quantum dots, achieving high concurrence with minimal noise and relaxation effects, using a sequence of four optical pulses.

Contribution

It introduces an adiabatic approach with analytic and numerical analysis for entangling spins in separate quantum dots, demonstrating high-fidelity entanglement over a broad parameter range.

Findings

Achieves spin entanglement with concurrence > 0.85

Uses four optical pulses of 0.1-1 ns duration

Minimizes noise and relaxation effects through adiabatic control

Abstract

We present an adiabatic approach to the design of entangling quantum operations with two electron spins localized in separate InAs/GaAs quantum dots via the Coulomb interaction between optically-excited localized states. Slowly-varying optical pulses minimize the pulse noise and the relaxation of the excited states. An analytic "dressed state" solution gives a clear physical picture of the entangling process, and a numerical solution is used to investigate the error dynamics. For two vertically-stacked quantum dots we show that, for a broad range of dot parameters, a two-spin state with concurrence $C>0.85$ can be obtained by four optical pulses with durations $\sim 0.1 - 1$ ns.