Strongly coupled ultracompressed self-cavity plasmon polaritons at millikelvin temperatures
Researchers created a novel platform using a Kinetic Inductance Broadside Cavity (KIBC) geometry and a Josephson junction spectrometer to probe strongly coupled cavity-matter systems at millikelvin temperatures. They successfully realized strong light-matter coupling between two distinct plasmonic modes—a cavity mode and a matter mode—demonstrating that superconducting KIBCs are an effective tool for studying the dynamic conductivity of quantum materials.