Complete nondestructive analysis of two-photon six-qubit hyperentangled Bell states assisted by cross-Kerr nonlinearity

TL;DR

This paper introduces a nondestructive method to fully distinguish hyperentangled Bell states across three degrees of freedom in two-photon systems using cross-Kerr nonlinearity, enhancing quantum communication capabilities.

Contribution

It presents the first complete scheme for hyperentangled Bell-state analysis in three DOFs with cross-Kerr nonlinearity, enabling nondestructive and comprehensive state discrimination.

Findings

Achieved complete nondestructive analysis of two-photon six-qubit hyperentangled Bell states.

Utilized cross-Kerr nonlinearity to construct quantum nondemolition detectors for parity-check measurements.

Potential applications in long-distance high-capacity quantum communication.

Abstract

Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum system, has attracted much attention as it can be used to increase both the channel capacity of quantum communication and its security largely. Here, we present the first scheme to completely distinguish the hyperentangled Bell states of two-photon systems in three DOFs with the help of cross-Kerr nonlinearity without destruction, including two longitudinal momentum DOFs and the polarization DOF. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors which can be used to make a parity-check measurement and analyze Bell states of two-photon systems in different DOFs. Our complete scheme for two-photon six-qubit hyperentangled Bell-state analysis may be useful for the practical applications in quantum information, especially in long-distance high-capacity quantum communication.