Breakthrough in Quantum Teleportation Over Hybrid Network Achieved

An international research team has achieved a critical breakthrough for quantum communication networks by demonstrating quantum teleportation between photons generated by two independent and dissimilar semiconductor quantum dots.

This achievement, published in Nature Communications, marks an essential step towards scalable quantum relays and a practical quantum internet. The challenge was to interface distinct quantum emitters with mismatched optical properties.

A collaboration between Paderborn University in Germany and Sapienza University of Rome in Italy engineered a complex experimental protocol to address this issue. They achieved a teleportation fidelity of 821%, surpassing the classical limit by more than ten standard deviations.

The solution involved two main engineering stages: controlling the quantum emitters, where GaAs quantum dots were embedded in nanophotonic cavities and integrated onto piezoelectric actuators to achieve ultra-low Fine Structure Splitting, necessary for generating high-fidelity entangled photon pairs.

The photons were also engineered for indistinguishability using magnetic fields to tune the emission wavelength and ultrafast superconductive nanowire single photon detectors for precise temporal post-selection.

The protocol was implemented in a hybrid quantum network over the Sapienza University campus in Rome, utilizing fiber connections and a 270 meter free-space optical link. This demonstration confirms the viability of using solid-state deterministic emitters for quantum relays, overcoming range limitations of terrestrial fiber networks.

The achievement lays the groundwork for the next phase, which is to demonstrate entanglement swapping between two deterministic quantum dot sources, a key requirement for building a true quantum repeater based on quantum dot emitters.

This development indicates that the implementation of a quantum dot-based quantum network for information processing is a likely prospect in the foreseeable future, according to the Quantum Computing Report.