Webinar

In the present work, we study the dynamics of a general null hypersurface in the Einstein Cartan (EC) theory generated by a null vector field 𝑙 α . We see that under a particular relation between the torsion tensor and the null generators called the geodesic constraint, the dynamical evolution of the Hajicek one-form is governed by the component 𝐺^ ab 𝑙 α qb c,  𝐺^ ab 𝑙 α qb c, where 𝑞 is the induced metric on an orthogonal spacelike cross-section of the null surface and 𝐺^ ab is the analogue of the Einstein tensor in spacetime with intrinsic torsion. Using the gravitational field equations for the EC theory, we see that above mentioned evolution equations can be provided a fluid-dynamical interpretation respectively. The relevant thermodynamic and fluid parameters have been properly identified. The dynamics of the Hajicek one-form has been studied in a local inertial frame and its correspondence with Cosserat fluid has been established.