Mediterranean neutrino observatory units new limits on quantum gravity – NanoApps Medical – Official web site

Quantum gravity is the lacking hyperlink between basic relativity and quantum mechanics, the yet-to-be-discovered key to a unified idea able to explaining each the infinitely massive and the infinitely small. The answer to this puzzle may lie within the humble neutrino, an elementary particle with no electrical cost and virtually invisible, because it hardly ever interacts with matter, passing by way of every little thing on our planet with out penalties.

For this very cause, neutrinos are troublesome to detect. Nevertheless, in uncommon circumstances, a neutrino can work together, for instance, with water molecules on the backside of the ocean. The particles emitted on this interplay produce a “blue glow” generally known as Čerenkov radiation, detectable by devices akin to KM3NeT.

The KM3NeT (Kilometer Dice Neutrino Telescope) is a big underwater observatory designed to detect neutrinos by way of their interactions in water. It’s divided into two detectors, one among which, ORCA (Oscillation Analysis with Cosmics within the Abyss), was used for this analysis. It’s positioned off the coast of Toulon, France, at a depth of roughly 2,450 meters.

Nevertheless, merely observing neutrinos shouldn’t be sufficient to attract conclusions in regards to the properties of quantum gravity—we should additionally search for indicators of “decoherence.”

As they journey by way of area, neutrinos can “oscillate,” which means they alter identification—a phenomenon scientists consult with as taste oscillations. Coherence is a basic property of those oscillations: a neutrino doesn’t have a particular mass however exists as a quantum superposition of three completely different mass states. Coherence retains this superposition well-defined, permitting the oscillations to happen frequently and predictably. Nevertheless, quantum gravity results might attenuate and even suppress these oscillations, a phenomenon generally known as “decoherence.”

“There are a number of theories of quantum gravity which by some means predict this impact as a result of they are saying that the neutrino shouldn’t be an remoted system. It might probably work together with the surroundings,” explains Nadja Lessing, a physicist on the Instituto de Física Corpuscular of the College of Valencia and corresponding writer of this examine, which incorporates contributions from lots of of researchers worldwide.

“From the experimental perspective, we all know the sign of this might be seeing neutrino oscillations suppressed.” This is able to occur as a result of, throughout its journey to us—or extra exactly, to the KM3NeT sensors on the backside of the Mediterranean—the neutrino might work together with the surroundings in a manner that alters or suppresses its oscillations.

Nevertheless, in Lessing and colleagues’ examine, the neutrinos analyzed by the KM3NeT/ORCA underwater detector confirmed no indicators of decoherence, a consequence that gives helpful insights.

“This,” explains Lessing, “signifies that if quantum gravity alters neutrino oscillations, it does so with an depth beneath the present sensitivity limits.” The examine has established higher limits on the energy of this impact, which at the moment are extra stringent than these set by earlier atmospheric neutrino experiments. It additionally supplies indications for future analysis instructions.

“Discovering neutrino decoherence can be a giant factor,” says Lessing. Up to now, no direct proof of quantum gravity has ever been noticed, which is why neutrino experiments are attracting rising consideration. “There was a rising curiosity on this subject. Individuals researching quantum gravity are simply very on this since you most likely couldn’t clarify decoherence with one thing else.”