Theory of fast optical spin rotation in a quantum dot based on geometric phases and trapped states

TL;DR

This paper proposes a fast optical method for electron spin rotation in quantum dots using geometric phases and trapped states, achieving high fidelity operations suitable for quantum computing.

Contribution

It introduces a novel approach leveraging geometric phases and trapped states for rapid spin manipulation in quantum dots, with exact solutions and high-fidelity numerical results.

Findings

Achieves spin rotation speeds up to two orders of magnitude faster than previous methods.

Provides an exact solution for a three-level quantum dot system under certain conditions.

Numerical simulations show operation fidelities exceeding 99% with realistic parameters.

Abstract

A method is proposed for the optical rotation of the spin of an electron in a quantum dot using excited trion states to implement operations up to two orders of magnitude faster than those of most existing proposals. Key ingredients are the geometric phase induced by 2$\pi$ hyperbolic secant pulses, use of coherently trapped states and use of naturally dark states. Our proposal covers a wide variety of quantum dots by addressing different parameter regimes. In one case the treatment provides an exact solution to the three-level system. Numerical simulations with typical parameters for InAs self-assembled quantum dots, including their dissipative dynamics, give fidelities of the operations in excess of 99%.