Entanglement swapping via three-step quantum walk-like protocol

• Published in: Physics letters. A Vol. 381; no. 46; pp. 3875 - 3879
• Main Authors: Li, Xiao-Man, Yang, Ming, Paunković, Nikola, Li, Da-Chuang, Cao, Zhuo-Liang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 13-12-2017
• Subjects: Entanglement swapping; Polarization entangled state; Quantum walk; Polarization entangled state; Quantum walk; Entanglement swapping
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/j.physleta.2017.10.022

We present an entanglement swapping process for unknown nonmaximally entangled photonic states, where the standard Bell-state measurement is replaced by a three-step quantum walk-like state discrimination process, i.e., the practically nontrivial coupling element of two photons is replaced by manipulating their trajectories, which will greatly enrich the dynamics of the coupling between photons in realizing quantum computation, and reduce the integration complexity of optical quantum processing. In addition, the output state can be maximally entangled, which allows for entanglement concentration as well.
•A quantum walk-like protocol is proposed for entanglement swapping.•It applies to unknown nonmaximally entangled photonic states.•Photons coupling is realized by manipulating the trajectories of them.•Entanglement concentration can be realized via walk-like evolutions.