# Manipulating photonic quantum states with long-range interactions

## TL;DR

This paper proposes a scheme to coherently manipulate photonic quantum states using long-range interactions, enabling tunable nonlinearities and entangled photon generation, with potential applications in quantum information processing.

## Contribution

It introduces a novel method for controlling photonic quantum states through nonlocal interactions, demonstrating new phenomena like entangled photon pairs and tunable photon interactions.

## Key findings

- Deterministic entangled photon pair generation
- Nonlinear beam splitting demonstrated
- Tunable dressed photon interactions achieved

## Abstract

We present a scheme for coherently manipulating quantum states of photons by incorporating multiple photonic modes in a system with long-range interactions. The presence of nonlocal photon-photon interactions destroys the energy or momentum matching conditions between distinct propagating polaritons, and consequently gives rise to blockaded effective coupling between the corresponding polaritons. Such a blockade mechanism protects the system from interaction-induced dissipations and enables highly tunable few-photon nonlinearities. Taking Rydberg atomic ensemble as an example, we illustrate several intriguing phenomena based on the proposed scheme, e.g., the deterministic generation of entangled photon pairs, the nonlinear beam splitting, as well as the establishment of a tunable dressed interaction between individual photons.