Einstein gravity with torsion induced by the spinor

Abstract

We consider spinor fields, minimally coupled to Einstein gravity with torsion in homogeneous and isotropic background in (2+1) dimensions. We set up the total action function of spin 1/2 particles with gravitation. We find the Dirac equation, Einstein and Cartan equations by taking the variation of the action with respect to the spinor field, the dreibein field and the Lorentz connection field. We solve these equations analytically for the spinor fields. We find the product of the spinor field and its conjugate takes a constant value. The circularly symmetric rotating exact solutions of Einstein and Cartan equations are found. (C) 2019 Elsevier Inc. All rights reserved.