Implementation of multi-walker quantum walks with cavity grid

TL;DR

This paper demonstrates how multi-walker quantum walks can be implemented using cavity quantum electrodynamics, revealing quantum features like entanglement, enhanced spreading, and localization, and explores decoherence effects.

Contribution

It presents a novel implementation method for multi-walker quantum walks in cavity QED systems, enabling exploration of quantum phenomena and decoherence effects.

Findings

Quantum walks show quadratic spreadings and localization effects.

Decoherence causes a transition from quantum to classical walks.

Average fidelity decay characterizes irreversibility due to decoherence.

Abstract

We show how multi-walker quantum walks can be implemented in a quantum quincunx created via cavity quantum electrodynamics. The implementation of a quantum walk with a multi-walker opens up the interesting possibility to introduce entanglement and more advanced walks. With different coin tosses and initial states the multi-walker quantum walk shows different probability distributions which deviate strongly from the classical random walks with quadratic enhanced spreadings and localization effects. By introducing decoherence, the transition from quantum walks to the classical versions is observed. We introduce the average fidelity decay as a signature to investigate the decoherence-induced irreversibility of quantum walks.