T. Harko, F. S. N. Lobo, M. K. Mak
Abstract
In this work, we derive the general solutions for a cylindrically symmetric space-time filled with a cosmological perfect fluid obeying p=γρ (0<=γ<=1), where γ=1 represents a stiff or Zeldovich fluid. Using Marder's metric with coefficients depending on t and r, we obtain explicit solutions of the gravitational field equations for the three cases δ=1,0,-1, corresponding to exponential, power-law, and trigonometric behaviors of the metric functions. The resulting space-times exhibit anisotropic evolution, nontrivial expansion and shear, and curvature singularities, with energy density and pressure profiles determined by the integration constants. These solutions provide a comprehensive framework for modeling cylindrically symmetric cosmologies, offering insights into early-universe dynamics and anisotropic gravitational phenomena. The versatility of the solutions also opens avenues for extensions to higher-dimensional or modified gravity scenarios, making them a valuable tool for both theoretical and phenomenological studies in general relativity.
The European Physical Journal C
Volume 86, Issue 960
2026 August
