Pressing a button on any electrical device sets off an orchestra of charged particles marching in time with the voltage in the circuit. But a new discovery in exotic materials known as strange metals has revealed that electricity doesn’t always move in time, and can actually sometimes leak in ways that make physicists question what we know about the nature of particles.

The research was carried out on nanowires made from a delicate balance of ytterbium, rhodium and silicon (YbRh).₂ Si₂). By performing a series of quantum measurement experiments on these nanowires, US and Austrian researchers have found evidence that could help resolve the debate about the nature of electric currents in metals that do not behave in conventional ways.

Discovered at the end of the last century in a class of copper-based compounds known for their lack of resistance to current at relatively high temperatures, the strange metals, like other metals, become more resistant to electricity when heated. But they do this in a rather strange way, increasing the resistance by a certain amount with each temperature increase. In common metals, the resistance varies with temperature and reaches a plateau once the material becomes sufficiently hot.

This contrast in resistance rules shows that currents in foreign metals do not behave in exactly the same way. For some reason, the way charge-carrying particles in strange metals interact with the repulsion of surrounding particles is different from the electron slalom in your average strip of wire.

What we can think of as a flow of negatively charged spheres passing through a tube of copper atoms is a little more complex. After all, electricity is a quantum affair with the properties of a set of particles known as quasiparticles, which behave harmoniously as separate entities.

Whether the same kind of quasiparticles could explain the unusual resistive behavior of strange metals remains an open question, as some theories and experiments suggest that such quasiparticles can lose their integrity under the right conditions. To find out whether there is a constant movement of particle-like particles in the flow of electrons in strange metals, the researchers used a phenomenon called shot noise.

If you can slow down the creep time, the photons of light emitted by even the most sensitive laser will pop and bounce with the predictability of sizzling bacon grease. This “noise” is a property of quantum probability and can serve as a measure of the granularity of charges flowing through a conductor.

“The idea is that if I start a current, it consists of a bunch of different charge carriers,” says senior author Doug Natelson, a physicist at Rice University in the US.

“They arrive at an average speed, but sometimes they’re closer together in time, sometimes they’re farther apart.”

The team found that the shot noise ratios in the ultrathin YbRh sample₂ Si₂ Typical interactions between electrons and their environment were strongly suppressed in a way that could not be explained, suggesting that quasiparticles were probably not involved.

Instead, the charge was more liquid-like than the currents in ordinary metals; This finding supports the model proposed more than 20 years ago by author Qimiao Si, a condensed matter physicist at Rice University. Xi’s theory of materials approaching zero temperature explains how electrons at individual locations no longer share properties that would allow them to form quasiparticles.

While ordinary quasiparticle behavior could previously be ruled out, the team isn’t exactly sure what form this “liquid” current takes or even whether it might be found in other strange metal descriptions.

“Perhaps this is evidence that quasiparticles are not well-defined things or do not exist, and that charge moves in more complex ways. We need to find the right words to talk about how charge might act collectively,” says Natelson. Source