Abstract
The long-wavelength dispersion of the phonon spectrum in liquid He4 can be computed from first principles. Part of the dispersion coefficient enters through the Feynman spectrum ε0(k), and the other part enters through corrections to ε0(k). The latter has been investigated by Jackson, Feenberg, and Lee using a perturbation expansion in the free-phonon basis. We define here a more plausible ordering scheme for the expansion and carry out the computation to second order.
| Original language | English |
|---|---|
| Pages (from-to) | 1536-1541 |
| Number of pages | 6 |
| Journal | Physical Review A - Atomic, Molecular, and Optical Physics |
| Volume | 1 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 1970 |
| Externally published | Yes |