Researchers have experimentally observed a hidden quantum geometry in materials that steers electrons similarly to how gravity bends light. The discovery, made at the interface of two oxide materials, could advance quantum electronics and superconductivity. Published in Science, the findings highlight a long-theorized effect now confirmed in reality.
Quantum materials, which operate under the rules of physics at atomic scales, hold promise for faster electronics and efficient energy flow. A team from the University of Geneva (UNIGE), the University of Salerno, and Italy's CNR-SPIN Institute has uncovered a key feature in these materials: the quantum metric.
This metric describes a curvature in quantum space that influences electron paths, much like Einstein's gravity warps light. Previously a theoretical idea from about 20 years ago, it was hard to detect experimentally. "The concept of quantum metric dates back about 20 years, but for a long time it was regarded purely as a theoretical construct. Only in recent years have scientists begun to explore its tangible effects on the properties of matter," said Andrea Caviglia, professor and director of UNIGE's Department of Quantum Matter Physics.
The researchers observed this effect at the boundary between strontium titanate and lanthanum aluminate, a setup known for quantum studies. They used intense magnetic fields to distort electron trajectories, revealing the metric's presence. Lead author Giacomo Sala, a research associate at UNIGE, explained: "Its presence can be revealed by observing how electron trajectories are distorted under the combined influence of quantum metric and intense magnetic fields applied to solids."
The study, detailed in the journal Science (DOI: 10.1126/science.adq3255), shows the quantum metric is common in many materials. This allows more precise measurements of optical, electronic, and transport properties. Caviglia added: "These discoveries open up new avenues for exploring and harnessing quantum geometry in a wide range of materials, with major implications for future electronics operating at terahertz frequencies, as well as for superconductivity and light-matter interactions."
Such insights build on quantum physics foundations that enabled transistors and modern computing, potentially leading to ultra-fast devices without energy loss.