Squeezed vibrational states in superfluid helium
Phys. Rev. B 114, 074510 – Published 26 August, 2026
DOI: https://doi.org/10.1103/9yqq-nqqx
Abstract
Ultrafast birefringence oscillations observed in superfluid helium provide evidence for anisotropic quantum squeezing of quasiparticle pairs. The measured response is a superposition of contributions from all vibrational modes, with dominant contributions from rotons, maxons, and Pitaevskii's plateau. The nonzero initial phase follows naturally from multimode interference.
