Neutrino production in a mixed-world cosmological model

Quantum-mechanical effects of a massless spinor field in an anisotropic metric of Bianchi type IX are analyzed. It is concluded from an analysis of the operator representing the second-quantized Hamiltonian of the field and the helicity operator that a pronounced initial anisotropy causes a change in the structure of the vacuum state of the spinor field, with the result that this state acquires a nonzero lepton charge. An analogy with a known situation in supercritical electric fields is pointed out.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 50–54, January, 1985.I wish to thank A. A. Grib and A. V. Nesteruk for useful discussions.