Low Temperature Physics: 33, 767 (2007); https://doi.org/10.1063/1.2780172 (7 pages)
Физика Низких Температур: Том 33, Выпуск 9 (Сентябрь 2007), c. 1008-1015    ( к оглавлению , назад )

The unusual properties of anisotropic systems of quasiparticles in superfluid 4He

I.N. Adamenko, K.E. Nemchenko, and V.A. Slipko

V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv 61077, Ukraine
E-mail: vaslipko@mail.ru

A.F.G. Wyatt

School of Physics, University of Exeter, Exeter EX4 4QL, UK
E-mail: a.f.g.wyatt@ex.ac.uk

Received October 1, 2006


We discuss a number of unusual phenomena, which have been discovered recently in anisotropic quasiparticle systems in superfluid 4He. These include the creation of high-energy phonons by a pulse of low-energy phonons, the suprathermal distribution of high-energy phonons in long phonon pulses, the mesa shape of the angular distribution of low-energy phonons, the creation of a «hot line» when two-phonon pulses cross. The thermodynamic properties of anisotropic quasiparticle systems of He II are derived for all degrees of anisotropy.

PACS: 67.40.Db Quantum statistical theory; ground state, elementary excitations;
PACS: 67.40.Fd Dynamics of relaxation phenomena.

Key words: superfluid 4He, quasiparticle anisotropic systems, phonon, roton.