Time-bin entangled state from two-photon through distinguishable pathways

Harishankar Jayakumar, Ana Predojević, Thomas Kauten +3 more

Xi-Han Li, Shohini Ghose

We present a complete hyperentangled Bell state analysis protocol for two-photon four-qubit states that are simultaneously entangled in the polarization and time-bin degrees of freedom. The 16 hyperentangled states can be unambiguously distinguished via two steps. In the first step, the polarization entangled state is distinguished deterministically and nondestructively with the help of the cross-Kerr nonlinearity. Then, in the second step, the time-bin state is analyzed with the aid of the polarization entanglement. We also discuss the applications of our protocol for quantum information processing. Compared with hyperentanglement in polarization and spatial-mode degrees of freedom, the polarization and time-bin hyperentangled states provide savings in quantum resources since there is no requirement for two spatial modes for each photon. This is the first complete hyperentangled Bell state analysis scheme for polarization and time-bin hyperentangled states, and it can provide new avenues for high-capacity, long-distance quantum communication.

Songyang Wu, Wen‐Xue Cui, Zhao Jin +2 more

A scheme is proposed for generating a long-distance two-photon entangled state in a noisy channel with the help of a cross-Kerr medium and photon number measurement via time-bin encoding and decoding. In the scheme, the influence of the noise can be eliminated effectively through time-bin encoding and decoding, the photon number detector is used to distinguish vacuum and nonvacuum states, and the minus conditional phase shift is not required. The method is also useful in other types of large-scale and long-distance quantum information processing via noisy channels.

Yoon-Ho Kim

Cheng‐Yan Gao, Bao‐Cang Ren, Yuan‐Xia Zhang +2 more

Abstract A linear optical unambiguous discrimination of hyperentangled Bell states is proposed for two‐photon systems entangled in both the polarization and momentum degrees of freedom (DOFs) assisted by time bin. This unambiguous discrimination scheme can completely identify 16 orthogonal hyperentangled Bell states using only linear optical elements, where the function of the auxiliary entangled Bell state is replaced by time bin. Moreover, the possibility of extending this scheme for distinguishing hyperentangled Bell states in n DOFs is discussed, and it shows that hyperentangled Bell states in n () DOFs can be distinguished with k () auxiliary entangled states of additional DOFs by introducing a time delay, which decreases the auxiliary entanglement resource required for unambiguous discrimination of hyperentangled Bell state. Therefore, this scheme provides a new way for distinguishing hyperentangled states with current technology, which will extend the application of discrimination of hyperentangled states via linear optics to other quantum information protocols besides hyperdense coding schemes in the future.

Petr M. Anisimov, William N. Plick, Christoph F. Wildfeuer +2 more