The Temperature Dependence of Phonon Velocity and Roton Minimum in Liquid He II
نویسندگان
چکیده
منابع مشابه
Temperature dependence of the phonon and roton excitations in liquid 4He.
We report high-precision neutron scattering measurements of the temperature dependence of the phonon and roton excitations in liquid He at saturated vapor pressure in both the superfluid and normal-fiuid phases. Two wave vectors were examined in detail: Q =0.4 A in the phonon region 0 and Q=1.925 A ' at the roton minimum. The goal is to understand excitations in Bose liquids by determining the ...
متن کاملPhonon-roton modes in liquid He coincide with Bose-Einstein condensation
We present neutron scattering measurements of the phonon-roton (P-R) and layer modes of liquid He confined in MCM-41 under pressure up to 38 bar. The data shows unambiguously that the P-R mode exists at low temperature only. As temperature is increased, there is a gradual transfer of intensity from the P-R mode to the normal liquid response, which lies at a lower energy at higher pressure. The ...
متن کاملPhonon-roton modes of liquid 4He beyond the roton in the porous medium MCM-41
R. T. Azuah,1,2 S. O. Diallo,3,* M. A. Adams,4 O. Kirichek,4 and H. R. Glyde3 1NIST Center for Neutron Research, Gaithersburg, Maryland 20899-8562, USA 2Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742-2115, USA 3Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716-2593, USA 4ISIS Spallation Neutron Source, Ruth...
متن کاملPhonon-roton excitations in liquid 4He at negative pressures.
We present neutron scattering measurements of the phonon-roton excitations of superfluid 4He held at negative pressures from zero to -5 bar. The liquid was stretched to negative pressures by immersing it in the porous medium MCM-41. In the wave vector range 0.35< or =Q< or =1.55 A(-1) and temperature T=0.4 K investigated, the phonon and maxon energies decrease systematically below bulk values a...
متن کاملExcitations in superfluid He beyond the roton
– High-energy resolution inelastic neutron scattering data on excitations in superfluid and normal He at SVP at wave vectors Q beyond the roton, 2.0 ≤ Q ≤ 4.0 Å −1 , are presented. The narrow energy resolution of these measurements reveals that the energy of the elementary excitation comes up to twice the roton energy, 2∆, at Q = 2.8 Å −1 and the energy remains constant at 2∆ between Q ' 3.0 Å ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Progress of Theoretical Physics
سال: 1973
ISSN: 0033-068X
DOI: 10.1143/ptp.49.388