Results 61 to 70 of about 51,631 (191)
Probing time orientability of spacetime
European Physical Journal C: Particles and Fields, 2023 In general relativity, cosmology and quantum field theory, spacetime is assumed to be an orientable manifold endowed with a Lorentz metric that makes it spatially and temporally orientable.
N. A. Lemos, D. Müller, M. J. Rebouças
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Quantum Cosmological Relational Model of Shape and Scale in 1-d
, 2011 Relational particle models are useful toy models for quantum cosmology and the problem of time in quantum general relativity. This paper shows how to extend existing work on concrete examples of relational particle models in 1-d to include a notion of ...
Abramowitz M +82 more
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Fortschritte der Physik, Volume 74, Issue 4, April 2026.Abstract String theory has strong implications for cosmology, implying the absence of a cosmological constant, ruling out single‐field slow‐roll inflation, and that black holes decay. The origins of these statements are elucidated within the string‐theoretical swampland programme.
Kay Lehnert
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A New Padé Approach to Modeling Wormholes in Dekel‐Zhao Dark Matter Halos
Annalen der Physik, Volume 538, Issue 3, March 2026.A matter‐first Padé strategy is introduced to build traversable wormholes from prescribed dark‐matter halos. Rational Padé fits approximately the Dekel–Zhao density and are analytically integrated to obtain a shape function that exactly reproduces the intended matter content, avoiding spurious poles of geometry‐first schemes.
Jonathan Alves Rebouças +4 more
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Non-singular bounce scenarios in loop quantum cosmology and the effective field description
, 2014 A non-singular bouncing cosmology is generically obtained in loop quantum cosmology due to non-perturbative quantum gravity effects. A similar picture can be achieved in standard general relativity in the presence of a scalar field with a non-standard ...
Cai, Yi-Fu, Wilson-Ewing, Edward
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A Re‐Examination of Foundational Elements of Cosmology
Fortschritte der Physik, Volume 74, Issue 3, March 2026.ABSTRACT This paper undertakes a conceptual re‐examination of several foundational elements of cosmology through the lens of spacetime symmetries. A new derivation of the Friedmann–Lemaître–Robertson–Walker metric is obtained by a careful conceptual examination of rotations and translations on generic manifolds, followed by solving the rotational and ...
Lavinia Heisenberg
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A Non-Polynomial Gravity Formulation for Loop Quantum Cosmology Bounce
Galaxies, 2017 Recently the so-called mimetic gravity approach has been used to obtain corrections to the Friedmann equation of General Relativity similar to the ones present in loop quantum cosmology.
Stefano Chinaglia +2 more
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, 2011 Gauge invariance of scalar perturbations is studied together with the associated equations of motion. Extending methods developed in the framework of hamiltonian General Relativity, the Hamilton-Jacobi equation is investigated into the details in Loop ...
Barrau, Aurelien, Cailleteau, Thomas
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Quasinormal Modes for Coherent Quantum Black Holes
Fortschritte der Physik, Volume 74, Issue 3, March 2026.ABSTRACT Coherent quantum black holes are quantum geometries obtained by means of a mean‐field‐like approach to the gravitational interaction. This procedure attenuates the classical spacetime singularities of general relativity by replacing them with integrable singularities in the quantum‐corrected geometry. After discussing some relevant observables
Tommaso Antonelli +3 more
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Living Reviews in Relativity, 2004 The observable universe could be a 1+3-surface (the "brane") embedded in a 1+3+$d$-dimensional spacetime (the "bulk"), with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk.
Maartens Roy
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