The generation of an entangled four-photon state from two pairs of entangled two-photon states by using linear optical elements

TL;DR

This paper proposes a linear optical scheme to generate entangled four-photon states from two entangled photon pairs, with potential to extend to larger multi-photon states for quantum information applications.

Contribution

The authors introduce a novel linear optical method to produce multi-photon entangled states from multiple entangled pairs, advancing quantum state engineering.

Findings

Successfully generates four-photon entangled states from two pairs.

The scheme can be extended to create larger N-photon entangled states.

Multi-photon states are useful for quantum tests and information processing.

Abstract

We present a scheme to produce an entangled four-photon state from two pairs of entangled two-photon states. Such entangled four-photon states are equivalent to the quantum state of two maximally entangled spin-1 particles. The scheme can also be generated to prepare an entangled 2N-photon state from N pairs of entangled two-photon states. Such multi-photon states play a crucial role in fundamental tests of quantum mechanics versus local realism and in many quantum information and quantum computation schemes.