Heralded generation of multiphoton entanglement

TL;DR

This paper introduces a linear optics-based scheme for heralded multiphoton entanglement generation from PDC, capable of producing large photon numbers and enhancing quantum metrology at the Heisenberg limit.

Contribution

It presents a novel, scalable method for generating multiphoton entangled states using standard photon detection and linear optics, applicable in both weak and strong interaction regimes.

Findings

Effective generation of multiphoton entanglement from PDC.

Compatibility with photon-number resolving detectors for large photon numbers.

Potential for quantum metrology at the Heisenberg limit.

Abstract

We present a scheme, based only on linear optics and standard photon detection, that allows to generate heralded multiphoton entangled states of arbitrary photon number from spontaneous parametric downconversion (PDC) in the weak interaction regime. The scheme also works in the strong interaction regime, i.e., for the production of large photon numbers, when photon-number resolving detectors with nearly perfect quantum efficiency are used. In addition, the same setup can be used for quantum metrology as multiphoton interferometer with sensitivity at the Heisenberg limit.