Bose-Einstein Condensation and Kinetic energy of liquid $^3$He-$^4$He Mixtures
| dc.creator | Diallo, S. O. | |
| dc.creator | Pearce, J. V. | |
| dc.creator | Azuah, R. T. | |
| dc.creator | Albergamo, F. | |
| dc.creator | Glyde, H. R. | |
| dc.date | 2006-09-20 | |
| dc.date.accessioned | 2026-07-07T07:23:39Z | |
| dc.date.available | 2026-07-07T07:23:39Z | |
| dc.description | We present neutron scattering measurements of the momentum distribution of liquid ${^3}$He-${^4}$He mixtures. The experiments were performed at wavevectors $Q$, 26 $\leq$ $Q$ $\leq$ 29 {Å$^{-1}$}, on the MARI time-of-flight spectrometer at the ISIS Facility, Rutherford Appleton Laboratory, a spallation neutron source. Mixtures with $^3$He concentrations $x$ between 0 and 20% were investigated both in the superfluid and normal phases. From the data, we extract the Bose-Einstein condensate fraction $n_0$ and the momentum distributions of $^3$He and $^4$He atoms. We find that $n_0$ increases somewhat above the pure $^4$He value when $^3$He is added; e.g from $n_0=(7.25\pm0.75)%$ at $x=$ 0 to $(11\pm3)%$ at $x=$ 15-20%. This agrees with predictions but is less than the only previous measurement. We find a $^4$He kinetic energy $K_4$ for pure $^4$He that agrees with previous determinations. $K_4$ decreases somewhat with increasing $^3$He concentration, less than observed previously and found in early calculations but in agreement with a more recent Monte Carlo calculation. The $^3$He response is not well reproduced by a Fermi gas momentum distribution, $n(\bf{k})$. Rather an $n(\bf{k})$ having a small step height at the Fermi surface and a substantial high momentum tail characteristic of a strongly interacting Fermi liquid provides a good fit. This $n(\bf{k})$ is consistent with calculated $n(\bf{k})$. Thus agreement between theory and experiment is obtained comparing $n(\bf{k})$ in contrast to earlier findings based on comparing calculated and observed $^3$He kinetic energies. | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0609529 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0609529 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/116058 | |
| dc.subject | Statistical Mechanics | |
| dc.subject | Superconductivity | |
| dc.title | Bose-Einstein Condensation and Kinetic energy of liquid $^3$He-$^4$He Mixtures | |
| dc.type | text |