Superposition of FLRW universes

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Gürses M., Heydarzade Y., Tekin B.

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, 2020 (SCI İndekslerine Giren Dergi) identifier identifier


We show that (1) the Einstein field equations with a perfect fluid source admit a nonlinear superposition of two distinct homogenous Friedman-Lemaitre-Robertson-Walker (FLRW) metrics as a solution, (2) the superposed solution is an inhomogeneous geometry in general, (3) it reduces to a homogeneous one in the two asymptotes which are the early and the late stages of the universe as described by two different FLRW metrics, (4) the solution possesses a scale factor inversion symmetry and (5) the solution implies two kinds of topology changes: one during the time evolution of the superposed universe and the other occurring in the asymptotic region of space.