Canadian scientists pioneer in creating highly efficient entangled photons

The team of scientists from the University of Waterloo in Canada has made substantial progress in the field of quantum communication. Their research focused on creating pairs of perfectly entangled photons, which they achieved with notable efficiency.

Photons that are quantumly entangled have a unique property - when the polarization of one is measured, the other always shows polarization in the opposite direction. This means they are connected, regardless of the distance separating them. This phenomenon of quantum entanglement was the subject of research that won the Nobel Prize in 2022.

In their research, scientists from the University of Waterloo used quantum dots - technology that won the Nobel Prize a year later, in 2023.

Professor Michael Reimer, the author of the publication on this topic, which appeared in the journal "Communications Physics", explains that "combining high-quality entanglement with high efficiency is crucial for such exciting applications as quantum key distribution or quantum repeaters, which can increase the range of secure quantum communication to a global scale or allow for the linking of distant quantum computers".

In the past, experiments focused on achieving either nearly perfect entanglement or high system efficiency. Now, thanks to the use of quantum dots, scientists have been able to achieve both goals.

The researchers applied several quantum dots in a nanowire, which allowed them to create a source of perfectly entangled photons, up to 65 times more efficient than previous solutions.

This system generates entangled photons when illuminated by a laser. The scientists did not stop at its creation alone. They have already demonstrated that it can be used to implement what is known as quantum key distribution, which is a fundamental procedure for secure quantum communication.