Physicists Use Electrical Noise To Crack Cuprate Mystery

A team of physicists says it has found a way to settle a nearly 40-year argument about why certain materials conduct electricity with zero resistance at relatively high temperatures. The method: listening to the faint electrical static made by current flowing through the material, according to Ars Technica.

The work, led by Milan Allan of Ludwig Maximilian University of Munich and Ingmar Swart of Utrecht University in the Netherlands, was published in the journal Science. It targets a puzzle inside copper-based materials called cuprates.

What did the physicists discover?

The team found a way to directly detect when electrons inside a cuprate material have paired up, something scientists have debated for decades. Those pairs, called Cooper pairs, are what let a superconductor carry current without losing energy to resistance.

"Other people think they're missing because they form pairs," Allan told Ars Technica, describing one of two competing explanations for a strange effect called the pseudogap.

What is the pseudogap, and why has it puzzled scientists?

Cuprates were discovered in the late 1980s to superconduct at temperatures reachable with liquid nitrogen, which is far warmer than the deep-freeze conditions most superconductors need, according to Ars Technica. That discovery made cheaper, more practical superconducting technology look possible. But scientists still cannot fully explain how cuprates do it.

Part of the problem is the pseudogap. Above the temperature where a cuprate turns superconducting, instruments detect far fewer electrons than expected at certain energy levels. "The pseudogap is a phenomenon of missing electrons," Allan said.

Two theories have competed to explain where those electrons went. One says the electrons freeze into fixed patterns, such as charge density waves, with superconductivity developing on a separate track. The other says the missing electrons are missing because they have already paired up, waiting in what amounts to a holding room before the whole material can superconduct together.

"Lots of different experimental signatures are kind of lumped inside this," Allan said. Prior instruments picked up hints, he said, but nothing conclusive: "It's always something kind of incoherent, hard to grasp."

How does listening to electrical noise reveal electron pairs?

The team's answer was to measure shot noise, the tiny fluctuations created when individual charges arrive in a current. Allan compared it to rain hitting a roof.

"If you imagine that you have raindrops and then all of a sudden you make the drops twice as heavy, there'll be more noise," Allan said. "With the electrons it's similar. If you have two electrons coming always together, because they're associated with pairing, then it will be more noise."

To capture that noise, the researchers used a scanning tunneling microscope. The instrument pushes current between a needle-sharp metal tip and the surface of a cuprate sample, letting the team record the electrical crackle at that tiny junction.

By the numbers

• Late 1980s — When cuprates were first found to superconduct at temperatures reachable with liquid nitrogen rather than far colder conditions, according to Ars Technica.
• Nearly 40 years — How long physicists have debated the cause of the pseudogap effect in cuprates, per the same report.
• Two — The number of lead institutions behind the new study: Ludwig Maximilian University of Munich and Utrecht University.
• One instrument — A scanning tunneling microscope was the single tool used to capture the shot-noise signal tied to electron pairing.

What happens next for superconductor research?

Timeline

• Late 1980s: Cuprates identified as high-temperature superconductors, sparking decades of research.
• Following decades: Competing theories emerge over the pseudogap — frozen electron patterns versus early electron pairing.
• 2026: Allan, Swart and colleagues publish shot-noise measurements in Science showing a direct signature of electron pairing.
• Nov. 8, 2026: Ars Technica reports on the findings.

The immediate effect of the study is scientific, not commercial. No new superconducting product ships because of this result. But for the field, a direct measurement of electron pairing gives researchers a sharper tool to test which theory of the pseudogap holds up, and to check other unconventional superconductors the same way.

For readers outside the lab, the practical payoff remains years away. Room-temperature superconductors that could cut power losses in the electrical grid or make cheaper MRI machines are still a goal, not a reality. What changed this week, according to the research team, is that physicists now have a cleaner way to listen for the signal that tells them pairing has already started — a step toward understanding why cuprates work at all.

Full findings and methodology are detailed in the original report from Ars Technica.