US researchers shake up ancient theory of electrical conductivity with groundbreaking discovery

US researchers have unveiled a groundbreaking discovery that challenges the long-established theory of electrical conductivity. 

Interesting Engineering unveils in a new article that in certain materials known as “strange metals,” electrons appear to lose their individual identities and merge into a featureless "quantum soup," which fundamentally disrupts the 60-year-old “Fermi liquid” theory of electrical flow in metals.

For over six decades, the Fermi liquid theory has served as the cornerstone of electrical conductivity. It suggests that despite their mutual repulsion, electrons move in clusters called quasiparticles, each carrying discrete charges. However, the new findings, based on precise “shot noise” measurements, suggest that in strange metals, electricity does not flow through discrete charges as previously thought.

“The Fermi liquid explanation of electrical transport is one of the foundational successes of condensed matter physics—the study of solid substances,” the researchers noted in a press release. “However, many new conductors, called ‘strange metals,’ do not conform to this paradigm.”

A key feature of strange metals is their unusual resistance behavior. Unlike conventional metals, whose resistance changes quadratically with temperature, the resistance in strange metals changes linearly at low temperatures. To investigate this anomaly, researchers used shot noise measurements to detect random fluctuations in electrical currents.

In the case of the strange metal YbRh2Si2, researchers found that shot noise was nearly zero, indicating a continuous, featureless flow of electricity. “It’s like electrons lose their identity and meld into a quantum soup,” the researchers explained.

This breakthrough challenges the conventional understanding of how electricity is carried by electrons and could have significant implications for the study of high-temperature superconductors and electrical transport.

“This new research could lead to a new theory of electrical transport,” the researchers concluded. The discovery is expected to spark further investigations into strange metals and offer new insights into condensed matter physics.

By Naila Huseynova