Weyssenhoff Fluid Sphere Models in Einstein-Cartan Theory

We obtain three models for Geodesic flows and three models for Non-Geodesic flows of Weyssenhoff fluid considering it as the source of gravitation and spin in the Einstein-Cartan field equations. Influence of spin on the pressure, density, equation of state and the kinematical parameters is observed in both geodesic and non-geodesic models.

Spin axioms in relativistic continuum physics

The 24 components of the relativistic spin tensor consist of 3 + 3 basic spin fields and 9 + 9 constitutive fields. Empirically only 3 basic spin fields and 9 constitutive fields are known. This empirem can be expressed by two spin axioms, one of them identifying 3 spin fields, and the other one 9 constitutive fields to each other. This identification by the spin axioms is materialindependent and does not mix basic spin fields with constitutive properties. The approaches to the Weyssenhoff fluid and the Dirac-electron fluid found in literature are discussed with regard to these spin axioms. The conjecture is formulated, that another reduction from 6 to 3 basic spin fields which does not obey the spin axioms introduces special material properties by not allowed mixing of constitutive and basic fields. .