Superfluidity of a perfect quantum crystal
Moscow State Evening Metallurgical Institute, Lefortovsky Val 26, Moscow, 111250, Russia
Corresponding author: a firstname.lastname@example.org
Revised: 18 June 2009
Published online: 18 August 2009
In recent years, experimental data were published which point to the possibility of the existence of superfluidity in solid helium. To investigate this phenomenon theoretically we employ a hierarchy of equations for reduced density matrices which describes a quantum system that is in thermodynamic equilibrium below the Bose-Einstein condensation point, the hierarchy being obtained earlier by the author. It is shown that the hierarchy admits solutions relevant to a perfect crystal (immobile) in which there is a frictionless flow of atoms, which testifies to the possibility of superfluidity in ideal solids. The solutions are studied with the help of the bifurcation method and some their peculiarities are found out. Various physical aspects of the problem, among them experimental ones, are discussed as well.
PACS: 03.75.Nt – Other Bose-Einstein condensation phenomena / 05.30.Jp – Boson systems / 67.80.bd – Superfluidity in solid 4He, supersolid 4He
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009