Optimal Control for Electron Shuttling

TL;DR

This paper develops an optimal control method to efficiently transfer electrons in quantum dot and dopant chains, enabling precise spatial and spin state manipulation for quantum information applications.

Contribution

It introduces a numerical optimal control algorithm for electron shuttling in quantum chains, including hyperfine interaction considerations.

Findings

Successfully transfers electrons in triple quantum dots and dopant chains.

Demonstrates control of electron spin states with magnetic fields.

Provides a practical approach for quantum state manipulation.

Abstract

In this paper we apply an optimal control technique to derive control fields that transfer an electron between ends of a chain of donors or quantum dots. We formulate the transfer as an optimal steering problem, and then derive the dynamics of the optimal control. A numerical algorithm is developed to effectively generate control pulses. We apply this technique to transfer an electron between sites of a triple quantum dot and an ionized chain of phosphorus dopants in silicon. Using the optimal pulses for the spatial shuttling of phosphorus dopants, we then add hyperfine interactions to the Hamiltonian and show that a 500 G magnetic field will transfer the electron spatially as well as transferring the spin components of two of the four hyperfine states of the electron-nuclear spin pair.