Efficient hyperconcentration of nonlocal multipartite entanglement via the cross-Kerr nonlinearity

TL;DR

This paper introduces two efficient schemes for hyperentanglement concentration in multipartite states using cross-Kerr nonlinearity, enabling near-unity success probabilities and reusability of unsuccessful instances for quantum information tasks.

Contribution

The paper presents novel hyperentanglement concentration schemes utilizing nondestructive parity checks with cross-Kerr nonlinearity, improving efficiency and reusability over previous methods.

Findings

Success probabilities approach unity with iteration.

Only one party needs to perform parity checks.

Schemes are applicable to quantum information processing.

Abstract

We propose two schemes for concentration of hyperentanglement of nonlocal multipartite states which are simultaneously entangled in the polarization and spatial modes. One scheme uses an auxiliary singlephoton state prepared according to the parameters of the less-entangled states. The other scheme uses two less-entangled states with unknown parameters to distill the maximal hyperentanglement. The procrustean concentration is realized by two parity check measurements in both the two degrees of freedom. Nondestructive quantum nondemolition detectors based on cross-Kerr nonlinearity are used to implement the parity check, which makes the unsuccessful instances reusable in the next concentration round. The success probabilities in both schemes can be made to approach unity by iteration. Moreover, in both schemes only one of the N parties has to perform the parity check measurements. Our schemes are efficient and useful for quantum information processing involving hyperentanglement.