An Invariant of Null Spinor Fields
A differential invariant is found for null fields of arbitrary spin. For null gravitational fields, the invariant is identified as that of Bičác and Pravda; its derivation from the Bel-Robinson tensor is given; and a simple expression is found for its value in null perturbations of flat spacetimes.
MSU Digital Commons Citation
Nita, Bogdan and Robinson, Ivor, "An Invariant of Null Spinor Fields" (2000). Department of Mathematics Facuty Scholarship and Creative Works. 41.