# Photonic Newton's Cradle for Remote Energy Transport

## TL;DR

This paper demonstrates a photonic analog of Newton's cradle that enables remote energy transfer through a controllable chain of coupled sites, advancing quantum simulation and Hamiltonian engineering.

## Contribution

It introduces a boundary-controlled photonic chain for long-range energy transfer, combining weak and strong couplings for efficient quantum state manipulation.

## Key findings

- High retrieval efficiency in uniform and defect-doped chains
- Successful demonstration of remote photon excitation transfer
- Potential for flexible Hamiltonian engineering

## Abstract

Energy transport is of central importance in understanding a wide variety of transitions of physical states in nature. Recently, the coherence and noise have been identified for their existence and key roles in energy transport processes, for instance, in a photosynthesis complex, DNA, and odor sensing etc, of which one may have to reveal the inner mechanics in the quantum regime. Here we present an analog of Newton's cradle by manipulating a boundary-controlled chain on a photonic chip. Long-range interactions can be mediated by a long chain composed of 21 strongly coupled sites, where single-photon excitations are transferred between two remote sites via simultaneous control of inter-site weak and strong couplings. We observe a high retrieval efficiency in both uniform and defect-doped chain structures. Our results may offer a flexible approach to Hamiltonian engineering beyond geometric limitation, enabling the design and construction of quantum simulators on demand.