Disappearance of Roton Propagation in Superfluid {sup 4}He at T{sub {lambda}}

Journal Article · Fri Nov 01 00:00:00 EST 1996 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.77.4398· OSTI ID:401147

Svensson, E C ^[1]; Montfrooij, W ^[2]; de Schepper, I M ^[3]

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1. Atomic Energy Chalk Limited, Chalk River Laboratories, Chalk River, Ontario, (Canada) KOJ 1JO
2. Netherlands Organization for Scientific Research (NWO), Den Haag (The Netherlands)
3. Interuniversitair Reactor Instituut, Delft University of Technology, Mekelweg 15, 2629JB Delft (The Netherlands)

Using neutron scattering, we determine the dynamic structure factor {ital S}({ital q},{nu}) of liquid {sup 4}He for the roton wave number {ital q}=2.0{sup {minus}1} as a function of frequency {nu} at constant density 0.1715 gcm{sup {minus}3} and for ten temperatures in the range 1.08{le}{ital T}{le}2.00 K, primarily near the superfluid transition temperature {ital T}{sub {lambda}}=1.9202 K. The {lambda} transition is marked by a complete softening of the roton mode and a rapid decrease in lifetime. This change is continuous with temperature, and we find no evidence for a new mode appearing as one enters the superfluid phase, as has been proposed on the basis of theoretical considerations. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 401147
• Journal Information: Physical Review Letters, Vol. 77, Issue 21; Other Information: PBD: Nov 1996
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
HELIUM 4
ROTONS
SUPERFLUIDITY
FREQUENCY DEPENDENCE
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
NEUTRON DIFFRACTION
CHALK RIVER NUCLEAR LABS