Researchers at the University of Waterloo's Institute for Quantum Computing (IQC) have efficiently produced nearly perfect entangled photon pairs from quantum dot sources.
Entangled photons are particles of light that remain connected, even across large distances. By combining entanglement with quantum dots, the research team aimed to optimize the process for creating entangled photons.
"The combination ... is needed for exciting applications such as quantum key distribution or quantum repeaters, which are envisioned to extend the distance of secure quantum communication to a global scale or link remote quantum computers," said Dr. Michael Reimer, professor at IQC and Waterloo's Department of Electrical and Computer Engineering.
"Previous experiments only measured either near-perfect entanglement or high efficiency, but we're the first to achieve both requirements with a quantum dot."
This research was recently published in the journal Communications Physics.
Near-perfect entangled photons
By embedding semiconductor quantum dots into a nanowire, the researchers created a source that creates near-perfect entangled photons 65 times more efficiently than previous work.
This new source can be excited with lasers to generate entangled pairs on command. The researchers then used high-resolution single photon detectors to boost the degree of entanglement.
Secure communications
To showcase future communications applications, the researchers used their new quantum dot entanglement source to simulate a secure communications method known as "quantum key distribution"—proving that the quantum dot source holds significant promise in the future of secure quantum communications.
Citation: Pennacchietti, M., Cunard, B., Nahar, S. et al. Oscillating photonic Bell state from a semiconductor quantum dot for quantum key distribution. Commun Phys 7, 62 (2024). https://doi.org/10.1038/s42005-024-01547-3 (open access)
