A joint research team has successfully demonstrated the complete confinement of mechanical waves within a single resonator—something long thought to be theoretically impossible. Their findings, published on April 3 in Physical Review Letters, mark a major breakthrough in the century-old mystery of bound states in the continuum (BIC). The team is from POSTECH (Pohang University of Science and Technology) and Jeonbuk National University.

A joint research team has successfully demonstrated the complete confinement of mechanical waves within a single resonator—something long thought to be theoretically impossible…Many technologies around us—from smartphones and ultrasound devices to radios—rely on resonance, a phenomenon in which waves are amplified at specific frequencies. However, typical resonators gradually lose energy over time, requiring constant energy input to maintain their function…“We have broken a long-standing theoretical boundary,” said Professor Junsuk Rho, who leads the research. “While this is still in the fundamental research phase, the implications are significant—from low-loss energy devices to next-generation sensing and signal technologies.”