Results 81 to 90 of about 32,545 (270)
DECOHERENCE FUNCTIONAL AND INHOMOGENEITIES IN THE EARLY UNIVERSE [PDF]
International Journal of Modern Physics D, 1993 We investigate the quantum to classical transition of small inhomogeneous fluctuations in the early Universe using the decoherence functional of Gell-Mann and Hartle. We study two types of coarse graining; one due to coarse graining the value of the scalar field and the other due to summing over an environment.
Laflamme, R., Matacz, A.
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Advanced Functional Materials, EarlyView.3D porous carbons with tunable density are crucial for energy storage, separations, and load‐bearing applications; however, their fabrication is often constrained by shrinkage during pyrolysis. This study optimizes and demonstrates the versatility of a template–coating pair strategy, producing materials that largely retain their shape and hierarchical ...
Adarsh Suresh +7 more
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Inhomogeneous dusty universes and their deceleration
Physics Letters B, 2006 Exact results stemming directly from Einstein equations imply that inhomogeneous Universes endowed with vanishing pressure density can only decelerate, unless the energy density of the Universe becomes negative. Recent proposals seem to argue that inhomogeneous (but isotropic) space-times, filled only with incoherent matter,may turn into accelerated ...
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A Termite‐Inspired Alternative to Cement
Advanced Functional Materials, EarlyView.A termite‐inspired composite of clay, cellulose, and lignin forms a dense fibrous network with concrete‐like strength (32 MPa) and superior elasticity, processed at ambient temperature. Abstract Clay combined with organic materials is used by termites as a strong and durable construction material for their mounds with minimal environmental impact. Here,
Oren Regev +3 more
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Modelling Inhomogeneity in the Universe [PDF]
Proceedings of 5th International School on Field Theory and Gravitation — PoS(ISFTG), 2009 An overview of some recent developments in inhomogeneous models is presented. As the volume and precision of cosmological data improves, it will become more and more essential to understand the non-linear behaviour of the Einstein field equations. This requires the study of exact inhomogeneous solutions, including their density distributions, their ...
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Advanced Functional Materials, EarlyView.Two‐photon lithography (TPL) enables 3D magnetic nanostructures with unmatched freedom in geometry and material choice. Advances in voxel control, deposition, and functionalization open pathways to artificial spin ices, racetracks, microrobots, and a number of additional technological applications.
Joseph Askey +5 more
wiley +1 more source
Inflationary quantum spectrum of the quasi-isotropic Universe
European Physical Journal C: Particles and FieldsWe investigate the quantum dynamics of the quasi-isotropic inflationary solution. This is achieved by deriving the Lagrangian and Hamiltonian for both the FLRW background and the inhomogeneous correction, via an expansion of the Einstein–Hilbert action ...
Nicola Bortolotti, Giovanni Montani
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On the cosmological constant problem
Physics Letters B, 2019 An additional variation of the Einstein-Hilbert action with respect to the Planck mass provides a constraint on the average Ricci scalar that prevents vacuum energy from gravitating. Consideration of the evolution of the inhomogeneous matter distribution
Lucas Lombriser
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Light propagation in inhomogeneous universes
The Astrophysical Journal, 1988 Refsdal's (1970) method is generalized to study the propagation of light rays through an inhomogeneous universe. The probability distribution for the linear component of the cumulative shear (CS) along light rays is derived, and it is shown that the CS can be dominated by nonlinear components, espcially for light rays in empty cones.
Peter Schneider, Achim Weiss
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Unprecedented Spin‐Lifetime of Itinerant Electrons in Natural Graphite Crystals
Advanced Functional Materials, EarlyView.Graphite exhibits extraordinary spintronic potential, with electron spin lifetimes reaching 1,000 ns at room temperature ‐ over 100 times longer than graphene‐based devices. Magnetic resonance spectroscopy reveals strong anisotropy: out‐of‐plane spins live 50 times longer than their in‐plane counterparts.
Bence G. Márkus +5 more
wiley +1 more source