Eur. Phys. J. D (2015) 69: 272
https://doi.org/10.1140/epjd/e2015-60430-y

Regular Article

Entangler and analyzer for four-photon χ-type entangled states

College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang 050024, P.R. China

^a e-mail: flyan@mail.hebtu.edu.cn

Received: 23 July 2015
Received in final form: 9 October 2015
Published online: 10 December 2015

Abstract

An entangler is proposed for generating χ-type polarization-entangled state using an EPR entangler, two Controlled-NOT (CNOT) gates and a Controlled-Z (CZ) gate. Furthermore, we also describe how to construct an analyzer for the sixteen χ-type entangled states with some m-qubit (m ≥ 2) parity gates and CNOT gates. Since the m-qubit parity gate can be constructed by m two-qubit CZ or CNOT gates, and the two-qubit parity gate can be configured to act as a Bell-state entangler, the implementation of the photonic two-qubit parity, CNOT and CZ gates is the key points in our scheme.