Quasideterministic realization of a universal quantum gate in a single scattering process

TL;DR

This paper demonstrates a method to implement a universal quantum CZ gate between two static spin-1/2 centers using a single scattering event of a flying particle in a 1D waveguide, without post-selection or internal spin requirements.

Contribution

It introduces a quasideterministic approach to realize a universal quantum gate through a single scattering process, leveraging boundary conditions and elastic scattering.

Findings

Single scattering can implement a CZ gate between static spins.

No post-selection or internal spin of the flying particle is needed.

Boundary conditions and elastic scattering are crucial for success.

Abstract

We show that a flying particle, such as an electron or a photon, scattering along a one-dimensional waveguide from a pair of static spin-1/2 centers, such as quantum dots, can implement a CZ gate (universal for quantum computation) between them. This occurs quasi-deterministically in a single scattering event, hence with no need for any post-selection or iteration, {and} without demanding the flying particle to bear any internal spin. We show that an easily matched hard-wall boundary condition along with the elastic nature of the process are key to such performances.