Discrete Time Quantum Walk Approach to State Transfer

TL;DR

This paper demonstrates that discrete time quantum walks with position-dependent coins can achieve quantum state transfer, revealing effects not observable in continuous time models, and explores their relation to continuous time quantum walks.

Contribution

It introduces a discrete time quantum walk model for state transfer, expanding the understanding of quantum walk dynamics and their potential advantages over continuous time models.

Findings

Discrete time quantum walks enable state transfer with unique effects.

Conversion between continuous and discrete time quantum walks is discussed.

The model extends quantum communication protocols in spin networks.

Abstract

We show that a quantum state transfer, previously studied as a continuous time process in networks of interacting spins, can be achieved within the model of discrete time quantum walks with position dependent coin. We argue that due to additional degrees of freedom, discrete time quantum walks allow to observe effects which cannot be observed in the corresponding continuous time case. First, we study a discrete time version of the engineered coupling protocol due to Christandl et. al. [Phys. Rev. Lett. 92, 187902 (2004)] and then discuss the general idea of conversion between continuous time quantum walks and discrete time quantum walks.