Results 41 to 50 of about 113,880 (205)

LETTER: A Simple Quantum Cosmology [PDF]

open access: yesGeneral Relativity and Gravitation, 2001
A simple and surprisingly realistic model of the origin of the universe can be developed using the Friedmann equation from general relativity, elementary quantum mechanics, and the experimental values of h, c, G and the proton mass. The model assumes there are N space dimensions (with N > 6) and the potential constraining the radius r of the ...
openaire   +4 more sources

Global and microlocal aspects of Dirac operators: Propagators and Hadamard states

open access: yesMathematische Nachrichten, EarlyView.
Abstract We propose a geometric approach to construct the Cauchy evolution operator for the Lorentzian Dirac operator on Cauchy‐compact globally hyperbolic 4‐manifolds. We realize the Cauchy evolution operator as the sum of two invariantly defined oscillatory integrals—the positive and negative Dirac propagators—global in space and in time, with ...
Matteo Capoferri, Simone Murro
wiley   +1 more source

Quantum cosmology from three different perspectives [PDF]

open access: yes, 2006
Our review is devoted to three promising research lines in quantum cosmology and the physics of the early universe. The nonperturbative renormalization programme is making encouraging progress that we here assess from the point of view of cosmological ...
Esposito, Giampiero
core   +2 more sources

Unification of Conformal and Fuzzy Gravities With Internal Interactions Resulting in SO(10) and a Possible Probe Through Stochastic Gravitational Wave Background

open access: yesFortschritte der Physik, EarlyView.
Abstract The unification of conformal and fuzzy gravities with internal interactions is based on the facts that i) the tangent group of a curved manifold and the manifold itself do not necessarily have the same dimensions and ii) both gravitational theories considered here have been formulated in a gauge theoretic way.
Gregory Patellis   +3 more
wiley   +1 more source

Causal Loop Quantum Gravity and Cosmological Solutions

open access: yes, 2004
We shall present here the causal interpretation of canonical quantum gravity in terms of new variables. Then we shall apply it to the minisuperspace of cosmology.
A Shojai   +16 more
core   +1 more source

Testing loop quantum cosmology [PDF]

open access: yes, 2017
Loop quantum cosmology predicts that quantum gravity effects resolve the big-bang singularity and replace it by a cosmic bounce. Furthermore, loop quantum cosmology can also modify the form of primordial cosmological perturbations, for example by ...
Wilson-Ewing, Edward
core   +2 more sources

QMM‐Enhanced Error Correction: Demonstrating Reversible Imprinting and Retrieval for Robust Quantum Computation

open access: yesAdvanced Quantum Technologies, EarlyView.
Hardware experiments show a single‐layer Quantum Memory Matrix booster cuts logical error sixfold and, when prepended to a [3,1,3]$[3,1,3]$ repetition code, attains 94 % logical fidelity without extra CX gates. QMM dressing also lowers variational‐training loss by 35 %, offering a measurement‐free, resource‐light route to error suppression on NISQ ...
Florian Neukart   +3 more
wiley   +1 more source

Minisuperspace Examples of Quantization Using Canonical Variables of the Ashtekar Type: Structure and Solutions

open access: yes, 1995
The Ashtekar variables have been use to find a number of exact solutions in quantum gravity and quantum cosmology. We investigate the origin of these solutions in the context of a number of canonical transformations (both complex and real) of the basic ...
A. Ashtekar   +18 more
core   +1 more source

Magnesium phosphate in the Cold Bokkeveld (CM2) carbonaceous chondrite

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract Hydrous Mg‐phosphate was first described from astromaterials in particles returned from the C‐type asteroid Ryugu, and has subsequently been found in samples of the B‐type asteroid Bennu and CI1 carbonaceous chondrites. This phase may have been highly significant as a source of bioessential compounds for early Earth.
Martin R. Lee   +2 more
wiley   +1 more source

Data‐Driven Review on Aerogels and Polymeric Aerogels

open access: yesAngewandte Chemie, Volume 137, Issue 28, July 7, 2025.
A review goes to data‐driven. An exhaustive literature survey provides an overview of research status on aerogels, a category of highly porous solids with unique physicochemical properties. Statistical/data‐driven analysis tells us positive/negative aspects; aerogels have a promising potential to contribute to emerging energy/environmental issues ...
Satoru Takeshita   +2 more
wiley   +2 more sources

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