Quantum interference and entanglement of photons which do not overlap in time

TL;DR

This paper explores the potential for quantum interference and entanglement between photons that do not overlap in time, demonstrating that their correlation functions can violate Bell's inequalities despite temporal separation.

Contribution

It introduces the concept that photons separated in time can still exhibit quantum entanglement and interference, challenging traditional notions of simultaneous photon interactions.

Findings

Two-photon correlation functions violate Bell's inequalities with time-separated photons.

Quantum interference can occur without temporal overlap of photons.

Entanglement persists across different time intervals.

Abstract

We discuss the possibility of quantum interferences and entanglement of photons which exist at different intervals of time, i.e., one photon being recorded before the other has been created. The corresponding two-photon correlation function is shown to violate Bell's inequalities.