Complete hyperentangled-Bell-state analysis for quantum communication

Abstract

It is impossible to unambiguously distinguish the four Bell states in polarization, resorting to linear optical elements only. Recently, the hyperentangled Bell state, the simultaneous entanglement in more than one degree of freedom, has been used to assist in the complete Bell-state analysis of the four Bell states. However, if the additional degree of freedom is qubitlike, one can only distinguish 7 from the group of 16 states. Here we present a way to distinguish the hyperentangled Bell states completely with the help of cross-Kerr nonlinearity. Also, we discuss its application in the quantum teleportation of a particle in an unknown state in two different degrees of freedom and in the entanglement swapping of hyperentangled states. These applications will increase the channel capacity of long-distance quantum communication.

Efficient multipartite entanglement purification with the entanglement link from a subspace

“…The principle of our QND is shown in Fig.1, similar to those in Refs. [38,40]. It is composed of two cross-Kerr nonlinearities (ck 1 and ck 2 ), four polarization beam splitters (PBSs), a coherent beam |α p , and an X quadrature measurement.…”

Hyperentanglement concentration for time-bin and polarization hyperentangled photons

“…Hyperentangled states can be used to beat the channel capacity limit of superdense coding with linear optics [23,24], construct hyper-parallel photonic quantum computing [25,26] which can reduces the operation time and the resources consumed in quantum information processing, achieve the high-capacity quantum communication with the complete teleportation and entanglement swapping in two DOFs [27,28]. They can also help to design deterministic entanglement purification protocols [29][30][31][32] which work in a deterministic way, not a probabilistic one, far different from conventional entanglement purifi- * Email address: xihanlicqu@gmail.com cation protocols [33][34][35].…”

Two-step measurement of the concurrence for hyperentangled state

“…The hyperentanglement can be used to complete the Bell-state analysis [22][23][24][25][26][27][28][29][30], perform the entanglement purification [31][32][33][34][35], and entanglement concentration [36]. It can also be used to extend the capacity of the channel in dense coding [27].…”