Autori: Hristu Culetu

Editorial: Centr. Eur. Jour. Phys., 6 (1), p.317 - 320, 2008.

Rezumat:

We take a null hypersurface (causal horizon) generated by a congruence of null geodesics as the boundary of the Doran – Lobo – Crawford spacetime to be the place where the Brown – York quasilocal energy is located. The components of the outer and inner stress tensors are computed and depend on time and the impact parameter $b$ of the test particle trajectory. The spacetime is a solution of Einstein’s equations with an anisotropic fluid as source.

The surface energy density $sigma$ on the boundary is given by the same expression as that obtained previously for the energy stored on the Rindler horizon. For long time intervals with respect to $b$ (when the stretched horizon tends to the causal one), the components of the stress tensors become constant.

Cuvinte cheie: orizont cauzal, geodezia nula, fluid anisotrop // causal horizon, null geodesic, anisotropic fluid