Quantum Corralling

TL;DR

This paper introduces a method using discrete time quantum walks with engineered local unitaries to robustly store, transport, and reconstruct quantum information with high fidelity over long distances.

Contribution

It presents a novel approach to quantum information transport employing only two types of local unitaries for dispersionless wave packet evolution.

Findings

Qubit confinement over long times achieved

Quantum information transported hundreds of sites

High-fidelity reconstruction demonstrated

Abstract

We propose a robust and efficient way to store and transport quantum information via one-dimensional discrete time quantum walks. We show how to attain an effective dispersionless wave packet evolution using only two types of local unitary operators (quantum coins or gates), properly engineered to act at predetermined times and at specific lattice sites during the system's time evolution. In particular, we show that a qubit initially localized about a Gaussian distribution can be almost perfectly confined during long times or sent hundreds lattice sites away from its original location and later almost perfectly reconstructed using only Hadamard and $\sigma_x$ gates.