The textbook understanding of electricity that most of us learned in school—electrons moving individually through metal—has been upended by new research into exotic materials known as “strange metals.” Scientists have found compelling evidence that in these materials, electrons don’t maintain their discrete identity but instead merge into what researchers describe as a “featureless liquid” or “quantum soup.”
For over six decades, the standard theory of electrical conductivity in metals, known as Fermi liquid theory, has explained how electricity flows. This theory recognizes that electrons don’t move completely independently but travel in “clumps” called electron quasiparticles due to their mutual repulsion. Despite this complexity, electricity was still understood to be carried by discrete charges.
New research focusing on the strange metal YbRh2Si2 suggests something radically different is happening in these materials.
The team employed a measurement technique called shot noise, which detects random fluctuations in electrical current. These fluctuations naturally occur because electrical current normally consists of discrete charges arriving at slightly different times—similar to raindrops hitting a roof during a light shower.
What makes this finding remarkable is that the shot noise measurements in strange metals revealed essentially no fluctuations, suggesting the current flows more like a continuous stream than discrete particles.
“It’s like electrons lose their identity and meld into a quantum soup,” notes the research team, drawing a striking analogy to explain this quantum blurring phenomenon.
To achieve these measurements, researchers had to overcome significant technical challenges. They fabricated nanoscale wires so tiny that electrons could pass through them faster than the time it takes to be affected by lattice vibrations in the metal, which would otherwise obscure the shot noise measurements.
Strange metals have puzzled physicists for years with their unusual properties. Unlike typical metals where resistance changes quadratically at low temperatures, strange metals exhibit linear resistance changes—a behavior that defies conventional understanding.
The implications of this research extend beyond pure physics curiosity. Understanding strange metals may unlock the secrets behind high-temperature superconductors, which behave like strange metals in their normal, non-superconducting state. Superconductors, materials that conduct electricity with zero resistance, have enormous potential for energy-efficient power transmission and other applications.
The claim that quasiparticles are absent in strange metals represents a fundamental challenge to established physics. Not all physicists are prepared to accept such a radical departure from the standard model of metals.
This research is expected to catalyze a wave of follow-up investigations as scientists grapple with developing new theories to explain how electricity can flow without discrete charge carriers.
The study was supported by various funding agencies including the Department of Energy Office of Science, Basic Energy Sciences program’s Experimental Condensed Matter Physics research area, the National Science Foundation, the European Research Council, and several other institutions.
As physicists continue to probe the mysterious behavior of strange metals, we may need to revise our fundamental understanding of how electricity works—an exciting prospect for next-generation technologies ranging from more efficient electronic devices to practical superconductors.
If our reporting has informed or inspired you, please consider making a donation. Every contribution, no matter the size, empowers us to continue delivering accurate, engaging, and trustworthy science and medical news. Independent journalism requires time, effort, and resources—your support ensures we can keep uncovering the stories that matter most to you.
Join us in making knowledge accessible and impactful. Thank you for standing with us!