Technology Physicist – Israel Institute of Technology says it has observed a new form of quantum entanglement in the total angular momentum of photons, limited to nanoscale structures. Their work paves the way for on-chip quantum information processing, using the total angular momentum of photons as an encoding property of quantum information.
The transformations that occur in two photon nanometric systems are intertwined in total angular momentum. Image credits: Shalom Buberman, Shultzo3d.
So far, quantum intertwining has been demonstrated for a wide variety of particles and their various properties.
In the case of photons, particles of light, entangled particles may be present in the direction of movement, frequency, or the direction in which the electric field is pointing.
It may also be the characteristics that are difficult to imagine, such as angular momentum.
This property is divided into spins related to the rotation of photons in the electric field, and is related to orbitals related to the rotational motion of photons in the universe.
“It’s easy to imagine these two rotational properties as separate quantities. In fact, photons are coupled to a beam of light much wider than the wavelength,” Professor Geibaltal and colleagues said in a statement.
“However, when we try to put photons in structures smaller than the photonic wavelength (a field effort in nanophotonics), it is impossible to separate different rotational properties, and we see that photons are characterized by a single amount, total angular momentum.”
“So why do you want to put photons in such a small structure? There are two main reasons for this.”
“One thing is clear: it helps narrow down devices that use light to miniaturize their electronic circuits.”
“Another reason is even more important. This miniaturization increases the interaction between photons and materials that are travelling (or nearby), allowing for phenomena and use that are not possible with photons of “normal” dimensions. ”
In their new study, researchers found that it is possible to entangle photons in nanoscale systems that are one-third of the size of hair, but entanglement is not performed solely by total angular momentum, depending on the conventional properties of photons, such as spins and orbits.
They uncover the process that occurs from the stage in which photons are introduced into the nanoscale system until they leave the measurement system, and found that this transition enriches the space in which the photons can live.
A series of measurements mapped their states to confirm the correspondence between photon pairs that were intertwined with the same properties inherent to nanoscale systems and exhibited quantum entanglement.
“This is the first discovery of new quantum entanglement in over 20 years, and could lead to the development of new tools for the design of photon-based quantum communications and computing components, as well as important miniaturization,” the scientists concluded.
Their paper Published in the journal Nature.
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A.Cam et al. Near-field photon entanglement in total angular momentum. NaturePublished online on April 2, 2025. doi:10.1038/s41586-025-08761-1
This article was adopted from the original release by Technion.
Source: www.sci.news
