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In this introductory review, we argue that a quantum structure of space-time naturally entails a higher-spin theory, to avoid significant Lorentz violation. A suitable framework is provided by Yang-Mills matrix models, which allow to…

High Energy Physics - Theory · Physics 2020-06-17 Harold C. Steinacker

The necessary and sufficient condition for the existence of $\alpha$-surfaces in complex space-time manifolds with nonvanishing torsion is derived. For these manifolds, Lie brackets of vector fields and spinor Ricci identities contain…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giampiero Esposito

In this article, I develop an elementary system of axioms for Euclidean geometry. On one hand, the system is based on the symmetry principles which express our a priori ignorant approach to space: all places are the same to us (the…

History and Overview · Mathematics 2021-06-01 Boris Čulina

We consider weighted parallel spinors in Lorentzian Weyl geometry in arbitrary dimensions, choosing the weight such that the integrability condition for the existence of such a spinor, implies the geometry to be Einstein-Weyl. We then use…

General Relativity and Quantum Cosmology · Physics 2011-11-16 P. Meessen , T. Ortín , A. Palomo-Lozano

We consider Yang-Mills theories formulated on a non-commutative space-time described by a space-time dependent anti-symmetric field $\theta^{\mu\nu}(x)$. Using Seiberg-Witten map techniques we derive the leading order operators for the…

High Energy Physics - Phenomenology · Physics 2009-11-10 Xavier Calmet , Michael Wohlgenannt

According to \textit{effective realism}, scientific theories give us knowledge about the unobservable world, but not at the fundamental level. This view is justified by the well-received \textit{effective-field-theory} (EFT) approach to…

History and Philosophy of Physics · Physics 2023-09-11 Lu Chen

A Weyl structure is usually defined by an equivalence class of pairs $({\bf g}, \boldsymbol{\omega})$ related by Weyl transformations, which preserve the relation $\nabla {\bf g}=\boldsymbol{\omega}\otimes{\bf g}$, where ${\bf g}$ and…

General Relativity and Quantum Cosmology · Physics 2019-11-01 Adria Delhom , Iarley P. Lobo , Gonzalo J. Olmo , Carlos Romero

We present the exact time-dependent solutions on inhomogeneous spherically symmetric space-time in the conformal invariant Weyl gravity. For this purpose, the subclass of the Lemaitre-Tolman metric which is supported by an anisotropic fluid…

General Relativity and Quantum Cosmology · Physics 2023-12-14 Malihe Heydari-Fard , Mohammad Rahim Bordbar , Golnaz Mohammadi

Our Universe has an arrow of time. In accordance with the second law of thermodynamics, entropy has been increasing ever since the Big Bang. The fact that matter is in thermal equilibrium in the very early Universe, as indicated by the…

General Relativity and Quantum Cosmology · Physics 2020-07-30 Daniele Gregoris , Yen Chin Ong , Bin Wang

We draw a picture of physical systems that allows us to recognize what is this thing called "time" by requiring consistency not only with our notion of time but also with the way time enters the fundamental laws of Physics, independently of…

Quantum Physics · Physics 2021-04-12 Caterina Foti , Alessandro Coppo , Giulio Barni , Alessandro Cuccoli , Paola Verrucchi

The running of quantum field theories can be studied in detail with the use of a local renormalization group equation. The usual beta-function effects are easy to include, but by introducing spacetime-dependence of the various parameters of…

High Energy Physics - Theory · Physics 2015-06-16 Benjamin Grinstein , Andreas Stergiou , David Stone

The notion of singular generalized Finsler spacetime and singular generalized Berwald spacetime are introduced and their relevance for the description of classical gravity discussed. A method to construct examples of such generalized…

Mathematical Physics · Physics 2020-08-04 Ricardo Gallego Torromé

Here we give a more detailed account of the part of the conference report that was devoted to reinterpreting the Einstein `unified models of gravity and electromagnetism' (1923) as the unified theory of dark energy (cosmological constant)…

General Relativity and Quantum Cosmology · Physics 2015-12-04 A. T. Filippov

We point out a new phenomenon which seems to be generic in 4d effective theories of scalar fields coupled to Einstein gravity, when applied to cosmology. A lift of such theories to a Weyl-invariant extension allows one to define classical…

High Energy Physics - Theory · Physics 2015-06-03 Itzhak Bars , Shih-Hung Chen , Paul J. Steinhardt , Neil Turok

According to the theory of unimodular relativity developed by Anderson and Finkelstein, the equations of general relativity with a cosmological constant are composed of two independent equations, one which determines the null-cone structure…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Robert Davis Bock

In this study, we investigate the dynamics of the Universe during the observed late-time acceleration phase within the framework of the Weyl-type $f(Q,T)$ theory. Specifically, we consider a well-motivated model with the functional form…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-23 M. Koussour , S. Myrzakulova , N. Myrzakulov

Weyl gravity has been advanced in the recent past as an alternative to General Relativity (GR). The theory has had some success in fitting galactic rotation curves without the need for copious amounts of dark matter. To check the viability…

Astrophysics · Physics 2008-12-30 A. Edery , M. B. Paranjape

We investigate if a recently introduced formulation of general relativity on a Weyl-integrable geometry, contains cosmological solutions exhibiting acceleration in the present cosmic expansion. We derive the general conditions to have…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Ricardo Aguila , José Edgar Madriz Aguilar , Claudia Moreno , Mauricio Bellini

A scale invariant, Weyl geometric, Lagrangian approach to cosmology is explored, with a a scalar field phi of (scale) weight -1 as a crucial ingredient besides classical matter \cite{Tann:Diss,Drechsler:Higgs}. For a particularly simple…

Astrophysics · Physics 2009-11-18 Erhard Scholz

We consider quasi-free stochastically positive ground and thermal states on Weyl algebras in Euclidean time formulation. In particular, we obtain a new derivation of a general form of thermal quasi-free state and give conditions when such…

Quantum Physics · Physics 2015-06-26 R. Gielerak , L. Jakobczyk , R. Olkiewicz