Spin swap vs. double occupancy in quantum gates

TL;DR

This paper introduces a method for implementing quantum gates using electron spins in semiconductors, leveraging controlled double occupancy and phase manipulation for fast quantum operations.

Contribution

It presents a novel approach that uses non-adiabatic tunneling control to utilize double occupancy for efficient quantum gate realization.

Findings

Achieves fast quantum gates through controlled double occupancy.

Demonstrates the half-swap operation as a building block for CNOT gates.

Utilizes phase control to optimize quantum gate performance.

Abstract

We propose an approach to realize quantum gates with electron spins localized in a semiconductor that uses double occupancy to advantage. With a fast (non-adiabatic) time control of the tunnelling, the probability of double occupancy is first increased and then brought back exactly to zero. The quantum phase built in this process can be exploited to realize fast quantum operations. We illustrate the idea focusing on the half-swap operation, which is the key two-qubit operation needed to build a CNOT gate.