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Eternal Universes

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arxiv 2404.03016 v2 pith:J3YLUQGB submitted 2024-04-03 hep-th gr-qc

Eternal Universes

classification hep-th gr-qc
keywords eternalbouncingcompleteenergyspacetimesuniversesamountbeginning
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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We consider the possibility of a past and future eternal universe, constructing geodesically complete inflating, loitering, and bouncing spacetimes. We identify the constraints energy conditions in General Relativity place on the building of eternal cosmological models. Inflationary and bouncing behavior are shown to be essential ingredients in all significant examples. Non-trivial complete flat spacetimes are shown to violate the null energy condition (NEC) for at least some amount of time. Ignoring the intractable subtleties introduced by quantum considerations, such as rare tunneling events and Boltzmann brains, we demonstrate that these universes need not have had a beginning or an end.

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Forward citations

Cited by 8 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Obstructions to Minimal Regular Black Hole Cosmologies

    gr-qc 2026-06 conditional novelty 7.0

    Obstructions from matching conditions and completeness theorems prevent minimal regular black hole models from hosting unbounded FRW daughter cosmologies.

  2. Chaos in Horndeski cosmologies

    gr-qc 2025-09 conditional novelty 7.0

    In Bianchi IX cosmologies, ordinary scalar fields kill mixmaster chaos when their energy is not subleading, but a phantom scalar then produces eternal, chaotic, non-singular bounces.

  3. Affine ANEC selects the closed FRW branch for geodesically complete cosmology

    gr-qc 2026-05 unverdicted novelty 6.0

    Affine ANEC obstructs non-static flat and open FRW from being null geodesically complete while ANEC-satisfying, but allows explicit scalar-field realizations for closed FRW with NEC-respecting matter.

  4. Geodesically Complete Curvature-Bounce Inflation

    astro-ph.CO 2026-04 unverdicted novelty 6.0

    Constructs an explicit closed FRW curvature-supported bounce-inflation model with a canonical scalar field that remains geodesically complete, NEC-compliant, and yields standard slow-roll predictions.

  5. Open case for a closed universe

    hep-th 2025-10 unverdicted novelty 6.0

    A no-go theorem proves flat and open FRW universes cannot be nonsingular, geodesically complete and ANEC-consistent while closed universes can, with positive curvature mimicking phantom dark energy at the 1% level.

  6. Obstructions to Minimal Regular Black Hole Cosmologies

    gr-qc 2026-06 conditional novelty 5.0

    A minimal FRW 'daughter universe' matched without a shell to an asymptotically flat regular black hole is either bounded (closed) or geodesically incomplete (flat/open), so a regular core alone cannot supply a viable ...

  7. Obstructions to Minimal Regular Black Hole Cosmologies

    gr-qc 2026-06 conditional novelty 5.0

    No-shell FRW daughters matched to asymptotically flat regular black holes are bounded if closed and past-incomplete if flat or open; a regular core alone cannot yield a viable daughter cosmology.

  8. Geodesically Complete Curvature-Bounce Inflation

    astro-ph.CO 2026-04 unverdicted novelty 5.0

    A closed k=+1 FRW universe with curvature-driven bounce and canonical scalar inflation remains sub-Planckian, satisfies the null energy condition, and produces ns=0.9617-0.9650 and r=0.0037-0.0045 consistent with data.