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

Quantum gravity is the lacking hyperlink between common relativity and quantum mechanics, the yet-to-be-discovered key to a unified principle 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 nearly invisible, because it not often interacts with matter, passing via every thing on our planet with out penalties.

For this very purpose, neutrinos are tough to detect. Nonetheless, 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” referred to as Čerenkov radiation, detectable by devices corresponding to KM3NeT.

The KM3NeT (Kilometer Dice Neutrino Telescope) is a big underwater observatory designed to detect neutrinos via their interactions in water. It’s divided into two detectors, one in every of 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.

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

As they journey via house, neutrinos can “oscillate,” which means they alter id—a phenomenon scientists seek advice from 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 totally different mass states. Coherence retains this superposition well-defined, permitting the oscillations to happen often and predictably. Nonetheless, quantum gravity results might attenuate and even suppress these oscillations, a phenomenon referred to as “decoherence.”

“There are a number of theories of quantum gravity which one way or the other predict this impact as a result of they are saying that the neutrino just isn’t an remoted system. It could possibly work together with the setting,” 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 might 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 setting in a manner that alters or suppresses its oscillations.

Nonetheless, in Lessing and colleagues’ examine, the neutrinos analyzed by the KM3NeT/ORCA underwater detector confirmed no indicators of decoherence, a consequence that gives useful 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 are actually extra stringent than these set by earlier atmospheric neutrino experiments. It additionally supplies indications for future analysis instructions.

“Discovering neutrino decoherence could be a giant factor,” says Lessing. To this point, no direct proof of quantum gravity has ever been noticed, which is why neutrino experiments are attracting growing consideration. “There was a rising curiosity on this subject. Individuals researching quantum gravity are simply very on this since you in all probability couldn’t clarify decoherence with one thing else.”