# Hyper-entanglement of photons emitted by a quantum dot

## TL;DR

This paper demonstrates the generation of hyper-entangled photons in polarization and time-bin degrees of freedom from a single quantum dot, advancing quantum communication capabilities.

## Contribution

It reports the first demonstration of polarization and time-bin hyper-entanglement from a quantum dot with high fidelity, using resonant coherent excitation.

## Key findings

- Fidelities of 0.81 and 0.87 in polarization and time-bin entanglement.
- Successful generation of hyper-entangled photons from a single quantum dot.
- Enhanced potential for quantum information protocols.

## Abstract

Entanglement is a unique quantum mechanical attribute and a fundamental resource of quantum technologies. Entanglement can be achieved in various individual degrees of freedom, nonetheless some systems are able to create simultaneous entanglement in multiple degrees of freedom - hyper-entanglement. A hyper-entangled state of light represents a valuable tool capable of reducing the experimental requirements and resource overheads and it can improve the success rate of quantum information protocols. Here, we report on demonstration of polarization and time-bin hyper-entangled photons emitted from a single quantum dot. We achieved this result by applying resonant and coherent excitation on a quantum dot system with marginal fine structure splitting. Our results yield fidelities to the maximally entangled state of 0.81(6) and 0.87(4) in polarization and time-bin, respectively.