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We discuss the way non-perturbative quantization of cosmological spacetimes in loop quantum cosmology provides insights on the physics of Planck scale and the resolution of big bang singularity. In recent years, rigorous examination of…

General Relativity and Quantum Cosmology · Physics 2009-03-27 Parampreet Singh

We consider the effects of the time dependence of couplings due to their dependence on a dilaton field, as occurs in superstring theory, as well as in gravity theories of the Jordan-Brans-Dicke type. Because the scale parameters of…

High Energy Physics - Phenomenology · Physics 2009-09-15 Bruce A. Campbell , Keith A. Olive

The existing approaches to quantization of gravity aim at giving quantum description of 3-geometry following to the ideas of the Wheeler -- DeWitt geometrodynamics. In this description the role of gauge gravitational degrees of freedom is…

General Relativity and Quantum Cosmology · Physics 2012-05-31 T. P. Shestakova

We consider the effective theory of perturbative quantum gravity coupled to a point particle, quantizing fluctuations of both the gravitational field and the particle's position around flat space. Using a recent relational approach to…

High Energy Physics - Theory · Physics 2022-02-02 M. B. Fröb , C. Rein , R. Verch

Big Bang Nucleosynthesis (BBN) offers one of the most strict evidences for the Lambda-CDM cosmology at present, as well as the Cosmic Microwave Background (CMB) radiation. In this work, our main aim is to present the outcomes of our…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-10 Sibel Boran , Emre Onur Kahya

The theory of scale relativity provides a new insight into the origin of fundamental laws in physics. Its application to microphysics allows us to recover quantum mechanics as mechanics on a non-differentiable (fractal) spacetime. The…

Quantum Physics · Physics 2011-07-13 Marie-Noëlle Célérier , Laurent Nottale

Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the testing ground upon which many cosmological models must ultimately rest. It is our only probe of the universe during the important radiation-dominated…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-20 Grant J. Mathews , Motohiko Kusakabe , Toshitaka Kajino

Quasiparticles may possess not only Berry curvature but also a quantum metric in momentum space. We develop a canonical formalism for such quasiparticles based on the Dirac brackets, and demonstrate that quantum metric modifies the…

High Energy Physics - Theory · Physics 2026-05-06 Kazuya Mameda , Naoki Yamamoto

If gravitons are super-strong interacting particles and the low-temperature graviton background exists, the basic cosmological conjecture about the Dopplerian nature of redshifts may be false. In this case, a full magnitude of cosmological…

High Energy Physics - Theory · Physics 2007-05-23 Michael A. Ivanov

An Ising-type classical statistical ensemble can describe the quantum physics of fermions if one chooses a particular law for the time evolution of the probability distribution. It accounts for the time evolution of a quantum field theory…

Quantum Physics · Physics 2015-06-04 C. Wetterich

The efforts in this contribution consist in reassessing a modified Dirac equation that incorporates a $\gamma^0 \gamma_5$-Lorentz-symmetry violating (LSV) term induced as a Loop Quantum Gravity (LQG) effect. Originally, this equation has…

High Energy Physics - Theory · Physics 2024-09-19 João Paulo S. Melo , Mario J. Neves , Jefferson M. A. Paixão , José A. Helayël-Neto

We explore nonlocally modified models of gravity, inspired by quantum loop corrections, as a mechanism for explaining current cosmic acceleration. These theories enjoy two major advantages: they allow a delayed response to cosmic events,…

Astrophysics · Physics 2011-05-31 S. Deser , R. P. Woodard

When gravity is quantized, there inevitably exist quantum gravitational vacuum fluctuations which induce quadrupole moments in gravitationally polarizable objects and produce a quantum correction to the classical Newtonian interaction…

General Relativity and Quantum Cosmology · Physics 2016-11-04 Puxun Wu , Jiawei Hu , Hongwei Yu

In a previous work and in terms of an exact quantum-mechanical framework, $\hbar$-independent causal and retarded expectation values of the second-quantized electro-magnetic fields in the Coulomb gauge were derived in the presence of a…

General Relativity and Quantum Cosmology · Physics 2018-12-26 Bo-Sture K. Skagerstam , Karl-Erik Eriksson , Per K. Rekdal

Dirac particle dynamics is encoded as a unitary path summation rule and implemented on a qubit array, where the qubit array represents both spacetime and the fermions contained therein. The unitary path summation rule gives a quantum…

Quantum Physics · Physics 2017-08-15 Jeffrey Yepez

In this work, we investigate Big Bang Nucleosynthesis (BBN) within the framework of $f(T,{L}_m)$ gravity, where the gravitational Lagrangian is generalized as a function of the torsion scalar $T$ and the matter Lagrangian ${L}_m$. We…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-25 Daniel F. P. Cruz , David S. Pereira , Francisco S. N. Lobo , José P. Mimoso

In this article, the axioms presented in the first one are reformulated according to the special theory of relativity. Using these axioms, quantum mechanic's relativistic equations are obtained in the presence of electromagnetic fields for…

Quantum Physics · Physics 2008-02-03 L. S. F. Olavo

Loop Quantum Gravity (L.Q.G.) is one of the two most promising tentative theory for a quantum description of gravity. When applied to the entire universe, the so-called Loop Quantum Cosmology (L.Q.C.) framework offers microscopical models…

General Relativity and Quantum Cosmology · Physics 2014-11-20 J. Grain

Quantum gravity corrections to the behavior of matter, such as Higgs bosons and fermions, are notoriously difficult to calculate. The standard tools of quantum field theory often break down, producing infinite results that spoil our…

General Physics · Physics 2025-09-22 Sebastián Alí Sacasa-Céspedes

Semiclassical gravity couples classical gravity to the quantized matter in meanfield approximation. The meanfield coupling is problematic for two reasons. First, it ignores the quantum fluctuation of matter distribution. Second, it violates…

General Relativity and Quantum Cosmology · Physics 2025-05-28 Lajos Diósi
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