Universal and optimal coin sequences for high entanglement generation in 1D discrete time quantum walks

Autor: Gratsea, Aikaterini, Metz, Friederike, Busch, Thomas
Rok vydání: 2020
Předmět:
Zdroj: 53(44):445306, Oct 2020
Druh dokumentu: Working Paper
DOI: 10.1088/1751-8121/abb54d
Popis: Entanglement is a key resource in many quantum information applications and achieving high values independently of the initial conditions is an important task. Here we address the problem of generating highly entangled states in a discrete time quantum walk irrespective of the initial state using two different approaches. First, we present and analyze a deterministic sequence of coin operators which produces high values of entanglement in a universal manner for a class of localized initial states. In a second approach, we directly optimize the sequence of coin operators using a reinforcement learning algorithm. While the amount of entanglement produced by the deterministic sequence is fully independent of the initial states considered, the optimized sequences achieve in general higher average values of entanglement that do however depend on the initial state parameters. Our proposed sequence and optimization algorithm are especially useful in cases where the initial state is not fully known or entanglement has to be generated in a universal manner for a range of initial states.
Comment: 9 pages, 6 figures, published in Journal of Physics A: Mathematical and Theoretical
Databáze: arXiv