Physicists Investigate Enigmas Surrounding Peculiar Metals

Physicists are delving into the peculiar behaviors exhibited by “strange metals,” which defy conventional rules of electricity. Yashar Komijani, a theoretical physicist and assistant professor at the University of Cincinnati, played a role in an international experiment focused on a strange metal composed of an alloy of ytterbium, a rare earth metal.

The experiment, conducted in a laboratory in Hyogo, Japan, involved firing gamma rays at the strange metal to observe its unconventional electrical characteristics. Led by Hisao Kobayashi from the University of Hyogo and RIKEN, the findings of the study were published in the journal Science. The experiment unveiled distinctive fluctuations in the strange metal’s electrical charge.

“In a metal, you have a sea of electrons moving in the background on a lattice of ions,” explained Komijani. “But a marvelous thing happens with quantum mechanics. You can forget about the complications of the lattice of ions. Instead, they behave as if they are in a vacuum.” Komijani has been dedicated to exploring the enigmas surrounding strange metals in the context of quantum mechanics for several years. “You can put something in a black box, and I can tell you a lot about what’s inside it without even looking at it, just by measuring things like resistivity, heat capacity, and conductivity,” he emphasized.

“But when it comes to strange metals, I have no idea why they are exhibiting the behavior they do. The mystery is what is happening inside this strange system. That is the question.” Strange metals captivate physicists across various fields, encompassing particle physics to quantum mechanics.

Their peculiarly high conductivity, particularly at extremely low temperatures, renders them promising as potential superconductors for quantum computing. “The thing that is really exciting about these new results is that they provide a new insight into the inner machinery of the strange metal,” remarked study co-author Piers Coleman, a distinguished professor at Rutgers University.

“These metals provide the canvas for new forms of electronic matter—especially exotic and high-temperature superconductivity,” he added. While it is premature to speculate about the technologies that strange metals might inspire, Coleman drew a parallel to Michael Faraday’s discovery of electromagnetism, which, despite initial uncertainty about its utility, led to groundbreaking innovations. “It is said that after Michael Faraday discovered electromagnetism, the British Chancellor William Gladstone asked what it would be good for,” Coleman recalled. “Faraday answered that while he didn’t know, he was sure that one day the government would tax it.” Drawing an analogy, Coleman suggested that strange metals could become similarly ubiquitous in future technologies. The Japan experiment proved groundbreaking, particularly due to the innovative use of a synchrotron—a particle accelerator that generated gamma particles.

Unlike conventional methods involving radioactive materials, this synchrotron in Japan produced gamma rays on demand. Spectroscopy was employed to examine the impact of gamma rays on the strange metal. Additionally, researchers investigated the speed of the metal’s electrical charge fluctuations, taking just a nanosecond—a billionth of a second. Although seemingly swift, in the quantum realm, a nanosecond is considered an extended duration. “However, in the quantum world, a nanosecond is an eternity,” Komijani noted. “For a long time, we have been wondering why these fluctuations are actually so slow. We came up with a theory with collaborators that there might be vibrations of the lattice, and indeed that was the case.”

This article is republished from PhysORG under a Creative Commons license. Read the original article.