Entanglement generation via diffraction

TL;DR

This paper demonstrates that simple diffracting systems like pinholes can generate quantum entanglement, offering an alternative to traditional interferometric methods and broadening potential applications in quantum technologies.

Contribution

It introduces the concept that diffraction can replace beam splitters for entanglement generation and provides conditions for entanglement creation in passive linear networks.

Findings

Diffracting systems can generate entanglement without complex interferometers.

Conditions for entanglement in passive linear networks are established.

Entanglement in free space can be utilized in various quantum applications.

Abstract

Quantum entanglement is an important resource for next-generation technologies. We show that diffracting systems can supplant beam splitters, and more generally interferometric networks, for entanglement generation -- systems as simple as screens with pinholes can create entanglement. We then discuss the necessary and sufficient conditions for entanglement to be generated by states input to any passive linear interferometric network. Entanglement generated in free space can now be harnessed in quantum-optical applications ranging from quantum computation and communication to quantum metrology.