This Strange Quantum “Dance” Could Rewrite Superconductivity

For the first time, researchers have imaged how pairs of electrons behave in a superconductor. Credit: Lucy Reading-Ikkanda/Simons FoundationScientists just revealed a hidden quantum “dance” that could reshape superconductivity.For the first time, scientists have directly visualized the quantum process behind superconductivity, a phenomenon in which electrons pair up and allow electricity to flow with no resistance at very low temperatures.The outcome was not what researchers anticipated.In a study published April 15 in Physical Review Letters, scientists captured images of individual atoms forming pairs inside a specially prepared gas cooled close to absolute zero — the unreachable limit to how cold things can get. This system, known as a Fermi gas, allows researchers to replace electrons with atoms and examine superconducting behavior in a controlled setting.Unexpected Behavior in Paired AtomsAfter forming pairs, the atoms did not behave as expected. Instead of acting independently, the pairs moved in a coordinated pattern, with each pair’s position influenced by nearby pairs — something not predicted by the 70-year-old, Nobel-prize-winning theory of superconductivity.“Our experiment showed that something is qualitatively missing from this theory,” says experimental research lead Tarik Yefsah of the Laboratoire Kastler Brossel at the French National Centre for Scientific Research (CNRS) in Paris. Yefsah and other experimental physicists at CNRS collaborated on the new study with theoretical physicists, including Shiwei Zhang of the Simons Foundation’s Flatiron Institute.This discovery adds a key detail to scientists’ understanding of superconductivity and may help guide efforts to develop room-temperature superconductors, a major goal that could lead to far more efficient power systems and electronic devices.An infographic explaining the first direct imaging of the quantum process underlying superconductivity. Credit: Lucy Reading-Ikkanda/Simons FoundationHow Superconductors Eliminate ResistanceSuperconductivity usually occurs in certain metals when they are cooled to extremely low temperatures — far below anything found naturally on Earth. Once the material drops below a critical temperature, electrical resistance disappears. This happens because electrons form pairs and move together, often compared to dancers moving across a ballroom floor.This basic explanation was developed in the 1950s by physicists John Bardeen, Leon Cooper, and John Robert Schrieffer.Limits of the BCS TheoryHowever, the BCS theory — named after its creators — is not a complete description. It does not fully explain every type of superconductor or capture all aspects of the phenomenon.

Scientists have long suspected that important details were missing, but they did not know exactly what.“BCS theory tells us superconductivity arises because electrons have a tendency to pair,” says Zhang, a senior research scientist and group leader at the Flatiron Institute’s Center for Computational Quantum Physics (CCQ). “But it’s a rough theory, and it doesn’t tell us anything about how the pairs interact.” According to this framework, pairs are spread independently throughout a material, so one pair should not affect another nearby.New Imaging Technique Reveals Pair InteractionsTo explore this gap, experimental physicists at CNRS worked with theorists at CCQ to study how pairs influence one another.Using a new imaging method, the team recorded snapshots of where paired atoms were located. They used a gas of lithium atoms cooled to just a few billionths of a degree Celsius above absolute zero. At these temperatures, the atoms behave as fermions, the same class of particles as electrons, making them a good model system.The images showed that the positions of paired atoms were linked. Each pair kept a certain distance from others, similar to how couples on a dance floor avoid colliding with one another. This pattern reveals interactions that are not included in the traditional BCS description.A Clearer View Inside the Quantum System“The BCS theory gives us a view from outside the ballroom, where we can hear the music and see the dancers come out, but we don’t know what’s going on in the ballroom,” Yefsah says. “Our approach is like taking a wide-angle camera inside the ballroom. Now we can see how the dancers are pairing up and paying attention to one another, so they don’t bump into each other.”To confirm the results, Zhang and his former postdoctoral researcher at the CCQ, Yuan-Yao He of the Institute of Modern Physics at Northwest University in China, performed detailed quantum simulations of the same system. The simulation results matched the experimental observations and reproduced the missing features, including the spacing between the paired “dancers.”Implications for Future SuperconductorsThese findings deepen understanding of superconductors and other quantum materials made of fermions. Such progress is essential for developing materials that can superconduct at higher temperatures.In the 1980s, scientists studying metal alloys discovered a class of high-temperature superconductors that work at temperatures near that of liquid nitrogen — still a cold minus 196 degrees Celsius (minus 321 degrees Fahrenheit). Scientists still do not fully understand why these materials function at these relatively higher temperatures.By improving knowledge of how superconductivity works at a fundamental level, researchers hope to eventually create materials that operate under everyday conditions. This could dramatically improve the efficiency of power grids and advanced computing systems.“By understanding this simple case, we can fine-tune our tools to study more complicated systems,” Zhang says. “And more complicated systems are where we look for new phases of matter, which have driven a lot of technological breakthroughs in the past.”Reference: “Observing Spatial Charge and Spin Correlations in a Strongly Interacting Fermi Gas” by Cyprien Daix, Maxime Dixmerias, Yuan-Yao He, Joris Verstraten, Tim de Jongh, Bruno Peaudecerf, Shiwei Zhang and Tarik Yefsah, 15 April 2026, Physical Review Letters. DOI: 10.1103/2t2k-3ftxNever miss a breakthrough: Join the SciTechDaily newsletter.Follow us on Google and Google News.