Results 31 to 40 of about 1,305 (201)
Cosmological constant problems and their solutions [PDF]
, 2004 There are now two cosmological constant problems: (i) why the vacuum energy is so small and (ii) why it comes to dominate at about the epoch of galaxy formation. Anthropic selection appears to be the only approach that can naturally resolve both problems.
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Physics Letters BThe (old) cosmological constant problem consists of two different problems. The first is the huge discrepancy between the value of the cosmological constant deduced from observations and its value expected from cosmological constant-like theoretical ...
Recai Erdem
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Quantum Theory, Noncommutative Gravity, and the Cosmological Constant Problem
Advances in Astronomy, 2009 The cosmological constant problem is principally concerned with trying to understand how the zero-point energy of quantum fields contributes to gravity. Here we take the approach that by addressing a fundamental unresolved issue in quantum theory, we can
T. P. Singh
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Semi-classical gravity in de Sitter spacetime and the cosmological constant
Physics Letters B, 2019 We show that there exist solutions to the semi-classical gravity equations in de Sitter spacetime sourced by the renormalised stress-energy tensor of a free Klein-Gordon field.
Benito A. Juárez-Aubry
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Revising the cosmological constant problem through a fluid different from the quintessence
Physical Sciences and Technology, 2022 The role of a scalar field is reexamined through the introduction of a quasi-quintessence model. Unlike quintessence, in the quasi-quintessence model, the pressure of the scalar field does not depend on its kinetic energy. This research note provides an
Orlando Luongo
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Cosmological constant problems and the renormalization group [PDF]
Journal of Physics A: Mathematical and Theoretical, 2007 The Cosmological Constant Problem emerges when Quantum Field Theory is applied to the gravitational theory, due to the enormous magnitude of the induced energy of the vacuum. The unique known solution of this problem involves an extremely precise fine-tuning of the vacuum counterpart.
Shapiro, Ilya L., Sola, Joan
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Environmental selection of the cosmological constant and electroweak scales
Journal of High Energy Physics, 2022 We investigate whether selfish/Goldilocks Higgs models can be extended to accomodate vacua with both the right Higgs mass and cosmological constant. Through the introduction of multiple four-form fields coupled with the Higgs scalar boson we find that ...
Matteo Moretti, Francisco G. Pedro
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Constraining the Swiss-Cheese IR-Fixed Point Cosmology with Cosmic Expansion
Universe, 2021 A recent work proposed that the recent cosmic passage to a cosmic acceleration era is the result of the existence of small anti-gravity sources in each galaxy and clusters of galaxies. In particular, a Swiss-cheese cosmology model, which relativistically
Ayan Mitra +4 more
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Scientific ReportsIn this article, we explicitly construct the coordinates associated with the Penrose diagram in spacetimes connected via a spacelike thin shell in the following two examples: the generalized black-to-white hole bounce with mass difference and the ...
Wei-Chen Lin +2 more
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Photonic‐Enabled Energy‐Efficient Transparent Neuromorphic Computing Devices: A Review
Advanced Science, EarlyView.Transparent photonic neuromorphic computing devices merge optics and brain‐inspired computing to overcome von Neumann bottlenecks with ultrafast, low‐energy processing. By exploiting transparent oxides, 2D materials, phase‐change materials, and hybrid heterostructures, these platforms enable photonic synapses, memory, and logic for see‐through edge ...
Shuvaraj Ghosh +8 more
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