Distribution of hybrid entanglement and hyperentanglement with time-bin for secure quantum channel under noise via weak cross-Kerr nonlinearity

Jino Heo,Jong-Phil Hong,Chang-Ho Hong,Hyung-Jin Yang,Seong-Gon Choi,Min-Sung Kang

doi:10.1038/s41598-017-09510-9

Abstract

We design schemes to generate and distribute hybrid entanglement and hyperentanglement correlated with degrees of freedom (polarization and time-bin) via weak cross-Kerr nonlinearities (XKNLs) and linear optical devices (including time-bin encoders). In our scheme, the multi-photon gates (which consist of XKNLs, quantum bus [qubus] beams, and photon-number-resolving [PNR] measurement) with time-bin encoders can generate hyperentanglement or hybrid entanglement. And we can also purify the entangled state (polarization) of two photons using only linear optical devices and time-bin encoders under a noisy (bit-flip) channel. Subsequently, through local operations (using a multi-photon gate via XKNLs) and classical communications, it is possible to generate a four-qubit hybrid entangled state (polarization and time-bin). Finally, we discuss how the multi-photon gate using XKNLs, qubus beams, and PNR measurement can be reliably performed under the decoherence effect.

Highlights

Entanglement is significantly involved in quantum information processing schemes, such as quantum communications[1,2,3], quantum computations[4,5,6], and quantum networks[7,8,9]
We show that the entanglement in a single degree of freedom (DOF) for two photons can be purified from correlation of the time-bin using only time-bin encoders (T1s and T2s) and linear optical devices under a noisy channel, and the purified entangled state in a single DOF can be extended to a hybrid entangled state of four photons in two DOFs via local operations (HEGs and T3s) and classical communications
We proposed several schemes (A through E) to generate and distribute hybrid entanglement and hyperentanglement for two DOFs using optical multi-qubit gates (HEG and photon gate (PG)), which utilize XKNLs, qubus beams, PNR measurement, and linear optical devices

Summary

Introduction

Entanglement is significantly involved in quantum information processing schemes, such as quantum communications[1,2,3], quantum computations[4,5,6], and quantum networks[7,8,9]. We propose schemes to generate and distribute hybrid entanglement and hyperentanglement between DOFs for polarization and time-bin using optical multi-qubit gates, which utilize XKNLs, qubus beams, and PNR measurement to obtain efficiency and robustness under the decoherence effect, and linear optical devices (including time-bin encoders).

Results

Conclusion