Abstract
The roton spectrum of superfluid helium apparently has a threshold for phonon emission and absorption processes. We calculate the roton spectral function near the threshold for phonon emission in order to determine the effect of the phonon emission process on the roton line width. The spectral function develops a line shape anomaly due to a strong energy dependence of the roton self-energy. The line width is generally smaller than the sum of the phonon emission rate and the roton-roton collision rate. We also derive the ultrasonic attenuation due to the absorption of phonons by thermal rotons above the threshold.
Full Text 
Sign-in/Register to access full text options
Sign-in/Register to access full text options 
Published version (
Free)
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
