General conditions for the generation of long-distance entanglement

Tomotaka Kuwahara

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

We generally investigate necessary conditions for the generation of long-distance entanglement. We consider a quantum system in which a system mediates the indirect interaction between two spins, which we refer to as probe spins. Firstly, we weaken the coupling between each probe spin and the mediator system to the infinitesimal strength in order to generate the long-distance entanglement. We give two necessary conditions for the mediator system to generate the long-distance entanglement. We prove that indirect interaction cannot generate the entanglement if it is 'classical'. We also give a necessary condition for the effective fields on the probe spins to satisfy. Secondly, we generate the long-distance entanglement by the use of only external fields. We show that external fields on the adjacent spins to the probes are necessary in addition to external fields on the probe spins. Finally, we consider the cases where the coupling strength between each probe spin and the mediator system is finite. In particular, we show two examples where the external fields on the mediator system highly enhance the long-distance entanglement.

Original languageEnglish
Article number123032
JournalNew Journal of Physics
Volume14
DOIs
Publication statusPublished - 2012 Dec 1

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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