Results 41 to 50 of about 51,631 (191)

Loop quantum cosmology of k=1 FRW models [PDF]

, 2006
The closed, k=1, FRW cosmology coupled to a massless scalar field is investigated in the framework of loop quantum cosmology using analytical and numerical methods.
Ashtekar, A, Pawlowski, T, Singh, P, Vandersloot, K   +3 more
core   +3 more sources

Shedding light on gravity: Black hole shadows and lensing signatures in Lorentz gauge theory

Nuclear Physics B
Recent advances, including gravitational wave detections and imaging of black hole shadows, have strongly validated general relativity. Nevertheless, ongoing cosmological observations suggest potential limitations of general relativity, spurring interest
Ali Övgün, Mohsen Fathi
doaj   +1 more source

Cosmological perturbations in a class of fully covariant modified theories: application to models with the same background as standard LQC

European Physical Journal C: Particles and Fields, 2018
Bouncing cosmologies are obtained by adding to the Einstein–Hilbert action a term of the form $$\sqrt{-\,g}f(\chi )$$ -gf(χ) , with $$\chi $$ χ a scalar depending on the Hubble parameter only, not on its derivatives, and which is here shown to arise from
Jaume de Haro, Llibert Aresté Saló, Emilio Elizalde   +2 more
doaj   +1 more source

Effective actions for loop quantum cosmology in fourth-order gravity

European Physical Journal C: Particles and Fields, 2021
Loop quantum cosmology (LQC) is a theory which renders the Big Bang initial singularity into a quantum bounce, by means of short-range repulsive quantum effects at the Planck scale.
Marcello Miranda, Daniele Vernieri, Salvatore Capozziello, Francisco S. N. Lobo   +3 more
doaj   +1 more source

A new cosmology of a crystallization process (decoherence) from the surrounding quantum soup provides heuristics to unify general relativity and quantum physics by solid state physics [PDF]

, 2021
We explore a cosmology where the Big Bang singularity is replaced by a condensation event of interacting strings. We study the transition from an uncontrolled, chaotic soup (“before”) to a clearly interacting “real world”. Cosmological inflation scenarios do not fit current observations and are avoided.
openaire   +1 more source

Generalized Rest Mass and Dirac’s Monopole in 5D Theory and Cosmology

Universe, 2021
It is shown that the 5D geodetic equations and 5D Ricci identities give us a way to create a new viewpoint on some problems of modern physics, astrophysics, and cosmology.
Boris G. Aliyev
doaj   +1 more source

A simple parity violating model in the symmetric teleparallel gravity and its cosmological perturbations

Physics Letters B, 2022
Parity violating models based on the symmetric teleparallel gravity have been considered in the literature, but their applications in cosmology and especially the features in cosmological perturbations have not been fully explored.
Mingzhe Li, Dehao Zhao
doaj   +1 more source

Quantum Gravity: General Introduction and Recent Developments

, 2005
I briefly review the current status of quantum gravity. After giving some general motivations for the need of such a theory, I discuss the main approaches in quantizing general relativity: Covariant approaches (perturbation theory, effective theory, and ...
Aharony, Amati, Ashtekar, Barbour, Bjerrum-Bohr, Blais, Bojowald, Borde, Brunnemann, Carlip, Carr, Coule, D'Eath, de Calan, Demers, Domagala, Goroff, Grøn, Halliwell, Hartle, Hawking, Hawking, Horowitz, Husain, Hájíček, Isham, Joos, Kiefer, Kiefer, Kiefer, Kiefer, Kiefer, Kiefer, Kiefer, Kiefer, Kimberly, Lauscher, Lin, Lämmerzahl, Majid, Meissner, Myers, Nicolai, Ooguri, Ooguri, Page, Polchinski, Reuter, Reuter, rn, Rosenfeld, Rovelli, Rovelli, Shepard, Thiemann, Weinberg, Wiltshire, Witten, Zeh, Zeh   +59 more
core   +1 more source

Universal Entanglement and an Information‐Complete Quantum Theory

Advanced Physics Research, EarlyView.
This Perspective summarize an informationcomplete quantum theory which describes a fully quantum world without any classical systems and concepts. Here spacetime/gravity, having to be a physical quantum system, universally entangles matter (matter fermions and their gauge fields) as an indivisible trinity, and encodes information‐complete physical ...
Zeng‐Bing Chen
wiley   +1 more source

Quantum Cosmology: Cosmology directly linked to the Planck Scale in General Relativity Theory and Newton Gravity

, 2023
We will in this paper demonstrate that there is a link between cosmology and the Planck scale. It has in recent years been shown that the Planck length can be found totally independent on \(G\), \(\hbar\) and \(c\) and that a series of cosmological predictions can be predicted only from two constants, namely the Planck length and the speed of gravity ...
openaire   +1 more source