Orientational dynamics of superfluid /sup 3/He: A ''Two-fluid'' model. II. orbital dynamics

Journal Article · Wed Feb 01 00:00:00 EST 1978 · Ann. Phys. (N.Y.); (United States)

DOI:https://doi.org/10.1016/0003-4916(78)90036-2· OSTI ID:7286597

Leggett, A J; Takagi, S

We present a phenomenological theory of the homogeneous orbital dynamics of the class of ''separable'' anisotropic superfluid phases which includes the ABM state generally identified with /sup 3/He-A. The theory is developed by analogy with the spin dynamics described in the first paper of this series; the basic variables are the orientation of the Cooper-pair wavefunction (in the ABM phase, the l-vector) and a quantity K which we visualize as the ''pseudo-angular momentum'' of the Cooper pairs but which must be distinguished, in general, from the total orbital angular momentum of the system. In the ABM case l is the analog of d in the spin dynamics and K of the ''superfluid spin'' S/sub p/. Important points of difference from the spin case which are taken into account include the fact that a rotation of l without a simultaneous rotation of the normal-component distribution strongly increases the energy of the system (''normal locking''), and that the equilibrium value of K is zero even for finite total angular momentum. The theory does not claim to handle correctly effects associated with any intrinsic angular momentum arising from particle-hole asymmetry, but it is shown that the magnitude of this quantity can be estimated directly from experimental data and is extremely small; also, the Landau damping does not emerge automatically from the theory, but can be put in in an ad hoc way. With these provisos the theory should be valid for all frequencies ..omega..very-much-less-than..delta.. (T)/h irrespective of the value of ..omega..tau. (..delta..=gap parameter, tau=quasi-particle relaxation time.) It disagrees with all existing phenomenological theories of comparable generality, although the disagreement with that of Volovik and Mineev is confined to the ''gapless'' region very close to T/sub c/.The phenomenological equations of motion, which are similar in general form to those of the spin dynamics with damping, involve an ''orbital susceptibility of the Cooper pairs'' chi/sub orb/(T).

• Research Organization: School of Mathematical and Physical Sciences, University of Sussex, Falmer, Brighton BN1 9QH, Sussex, United Kingdom
• OSTI ID: 7286597
• Journal Information: Ann. Phys. (N.Y.); (United States), Vol. 110:2
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HELIUM 3 A
KINETIC EQUATIONS
ANGULAR MOMENTUM
COOPER PAIRS
ENERGY GAP
LANDAU DAMPING
SUPERFLUIDITY
DAMPING
EQUATIONS
EVEN-ODD NUCLEI
HELIUM 3
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
STABLE ISOTOPES
640450* - Fluid Physics- Superfluidity