3 papers
gr-qc2026
Peculiar velocity fields from analytic solutions of General Relativity
Roberto A. Sussman, Sebastián Nájera, Fernando A. Pizaña +1
Peculiar velocities are analyzed through cosmological perturbations in the Newtonian longitudinal gauge characterized by irrotational shear-free congruences in an Eulerian frame. W…
gr-qc2025
Revisiting the gravitational "arrow of time"
Roberto A. Sussman, Sebastián Nájera, Fernando A. Pizaña +1
We address a long-standing misperception on the gravitational ``arrow of time'', a proposal by Penrose (also known as the ``Weyl-curvature hypothesis") that associates structure fo…
gr-qc2025
Gravitational entropy of fluids with energy flux
Roberto A. Sussman, Sebastián Nájera, Fernando A. Pizaña +1
We examine gravitational entropy growth within the formalism of Clifton, Ellis and Tavakol (CET) applied to a class of spherically symmetric exact solutions whose source is a shear…