Condensate and final-state effects in superfluid {sup 4}He

Journal Article · Mon Dec 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.56.14620· OSTI ID:550539

Azuah, R T; Stirling, W G ^[1]; Glyde, H R; Boninsegni, M ^[2]; Sokol, P E ^[3]; Bennington, S M ^[4]

---

1. Department of Physics, University of Keele, Keele ST5 5BG (United Kingdom)
2. Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)
3. Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
4. ISIS Division, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom)

We present high-precision measurements of the dynamics of single atoms in superfluid {sup 4}He at T=1.6 K and saturated vapor pressure. The measurements were taken on the MARI instrument at the ISIS neutron-scattering facility, Rutherford-Appleton Laboratory. From the measurements we obtain a condensate fraction n{sub 0}=6.0{plus_minus}2.0{percent} at T=1.6 K. The final-state effects (FSE{close_quote}s) in the atomic response are also determined from the data in the form of a final-state broadening function, R(Q,y). We find that this FS function is the same in the superfluid at T=1.6 K as that determined previously in normal {sup 4}He at T=2.3 K. If we reanalyze the data assuming that the superfluid has no condensate, i.e., n{sub 0}=0, then the data requires that the normal n({bold k}) change dramatically between T=2.3 K and T=1.6 K. Since such a change in n({bold k}) is physically unexpected, given that kT is much less than the zero-point energy, the data requires that a new contribution, such as a condensate, enter n({bold k}) in the superfluid. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 550539
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 22 Vol. 56; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BOSE-EINSTEIN CONDENSATION
CONDENSATES
HELIUM 4
NEUTRON DIFFRACTION
PHASE TRANSFORMATIONS
SUPERFLUIDITY
TEMPERATURE RANGE 0000-0013 K