A Single Photon Revealed the Theory Behind the Quantum Networks of the Future

Quantum entanglement of 16 million atoms.


Quantum theory explains the nature and behavior of matter and energy on the atomic and subatomic level. The theory also referred as quantum mechanics. However, the entanglement between atoms can be intertwined due to quantum forces, across distances, or inside macroscopic structures. But, the actual evidence has been mostly lacking.

In a new study by the University of Geneva, scientists entangled 16 million atoms in a one-centimeter crystal.

Florian Fröwis, a researcher in the applied physics group in UNIGE’s science faculty explained, “It is relatively easy to entangle two particles: splitting a photon, such as, generates two entangled photons that have identical properties and behaviors. But, it is impossible to directly observe the process of entanglement between several million atoms since the mass of data you need to collect and analyze is so huge.”

A Single Photon Confirmed the Theory Behind the Quantum Networks of the Future
Partial view of the source producing the single photons that were stored in the quantum memory to produce entanglement between many atoms inside the memory. (UNIGE)

Scientists primarily observed the characteristics of light re-emitted by the crystal. They also analyzed its statistical properties and the probabilities. For this, they settled on the single direction of light re-emitted by the crystal. In this way, the researchers succeeded in showing the entanglement of 16 million atoms.

However, particle entanglement in quantum physics is quite difficult to understand. This is reasonably a new type of correlation, infinitely stronger and more mysterious, emerges: entanglement.

In future, Quantum networks will offer data protection as they send and detect signal at any interception of that signal by a third-party. These signals are sent and received by quantum repeaters. Quantum repeaters unify entangled atoms with a strong quantum relationship despite being separated by great distances. These quantum repeaters house crystal blocks supercooled to 270 degrees below zero and enriched with rare earth atoms. Once these blocks are penetrated by a photon, entanglement is created.


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