Vanishing Phase Stiffness and Fluctuation-Dominated Superconductivity in UTe 2
The study investigated UTe2 under pressure using ultrasound to probe its superconducting state. It found a fluctuation regime extending over a wide temperature range, suggesting an exotic state driven by inter-band pairing mediated by ferromagnetic fluctuations. This points to two distinct superconducting phases: SC1 (intra-band) and SC2 (inter-band), with SC2 having unusually low phase stiffness.