Physicists Expose Accidental Discovery of a New Quantum Particle

While metals and insulators differ in definition, Princeton physicist has accidentally detected an unexpected quantum behavior in an insulator believed to be distinctive to metals.

According to New Atlas, such a discovery proposes a brand-new quantum particle type, which the research team identifies as a "neutral fermion."

Basically, metals are conducting electricity while insulators aren't. On the molecular level, the said report describes, it comes down to how liberally electrons can move through the materials, specifically in metals, electrons are quite mobile. At the same time, insulators are evidently characterized by high resistance that stops them from moving much.

As a side effect of such activity, metals can display a phenomenon also called quantum oscillations. When exposed to a magnetic field at such low temperatures, electrons can switch to a quantum condition that causes the oscillation of the resistivity of a material.

This does not happen in insulation, though, since their electrons do not move quite well. Or, according to the physicist, at least, that was the conservative perception for the better part of a hundred years.

First-Time Discovery of Quantum Oscillations

For the first time in this new research, the Princeton researchers discovered quantum oscillations in an insulator. As specified in the report, the team worked with tungsten ditelluride, a substance with a behavior similar to the metal in bulk that turns into an insulator when it is shaved down into a "two-dimensional form" akin to graphene.

While gauging the monolayer material's resistivity within a magnetic field, the researchers found that it started to oscillate.

According to the senior author of the study, Sanfeng Wu, such a discovery "came as a complete surprise" to them. In the team, Wu also said they asked themselves, "What's going on here?" as they do not understand it yet.

The phenomenon, the report said, cannot be explained by the ongoing theories. Still, the study investigators "have put forward their own hypothesis" claiming, it may not be the electrons themselves "that are oscillating."

Instead, they explained, the strong interactions might be generated new particles that display the observed impact.

New Quantum World Hiding in an Insulator

Since insulators are blocking charged particles, like electrons, from moving liberally, such new particles would need to have a neutral charge.

These so-called hypothetical "neutral fermions" could then present observed oscillations of quantum particles. Wu explained, if there are right with their interpretations, they see an essentially "brand-new form of quantum matter."

The senior author added, it is probable that they simply missed out on identifying them over the past several decades.

According to the research team, more work is needed for them to confirm if neutral fermions indeed exist or if there are some other explanations for the oddities they have observed.

Commenting on their study, Wu also said it is possible that the neutral fermions could be utilized in the future for the encoding of information that would be "helpful in quantum computing."

Momentarily though, he continued, they are still in the very early stages of understanding such phenomena like this one, and thus, "fundamental discoveries need to be made."

This study Princeton University conducted was published in the Nature journal on January 4, 2021.

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