A Low Complexity Scheme for Entanglement Distributor Buses

TL;DR

This paper proposes a low-complexity, symmetry-breaking scheme using magnetic flux in spin networks to efficiently generate entanglement between qubit pairs, suitable for nanoscale quantum processors.

Contribution

It introduces a simple control method using symmetry breaking to enhance entanglement distribution in spin networks, improving efficiency and practicality.

Findings

Entanglement can be maximized by breaking symmetry with magnetic flux.

Controlling a single vertex suffices to entangle specific qubit pairs.

The scheme is suitable for implementation in nanoscale quantum devices.

Abstract

For technological purposes and theoretical curiosity, it is very interesting to have a building block that produces a considerable amount of entanglement between on-demand sites through a simple control of a few sites. Here, we consider permanently-coupled spin networks and study entanglement generation between qubit pairs to find low-complexity structures capable of generating considerable entanglement between various qubit pairs. We find that in axially symmetric networks the generated entanglement between some qubit pairs is rather larger than generic networks. We show that in uniformly-coupled spin rings each pair can be considerably entangled through controlling suitable vertices. To set the location of controlling-vertices, we observe that the symmetry has to be broken for a definite time. To achieve this, a magnetic flux can be applied to break symmetry via Aharonov-Bohm effect. Such a set up can serve as an efficient entanglement distributor bus in which each vertex-pair can be efficiently entangled through exciting only one fixed vertex and controlling the evolution time. The low-complexity of this scheme makes it attractive for use in nanoscale quantum information processors.