# Edge states of photon pairs in cavity arrays with spatially modulated nonlinearity

## TL;DR

This paper theoretically investigates a one-dimensional array of nonlinear cavities with spatially modulated interactions, revealing that such modulation induces bound two-photon edge states explained through nonlinear self-localization.

## Contribution

It introduces a novel extended Bose-Hubbard model with spatially modulated nonlinearity, demonstrating the emergence of two-photon edge states due to this modulation.

## Key findings

- Spatial modulation of nonlinearity induces bound two-photon edge states.
- Edge states are explained via nonlinear self-localization.
- The model advances understanding of photon behavior in nonlinear cavity arrays.

## Abstract

We study theoretically an extended Bose-Hubbard model with the spatially modulated interaction strength, describing a one-dimensional array of tunneling-coupled nonlinear cavities. It is demonstrated that the spatial modulation of the nonlinearity induces bound two-photon edge states. The formation of these edge states has been understood analytically in terms of nonlinear self-localization.