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The corrections to holographic entanglement entropy from bulk quantum fields in a classical gravitational background are now well understood. They lead, in particular, to unitary Page curves for evaporating black holes. However, the correct…

High Energy Physics - Theory · Physics 2025-06-18 Sean Colin-Ellerin , Guanda Lin , Geoff Penington

Gravitational waves (GWs) provide a unique opportunity to test General Relativity (GR) in the highly dynamical, strong-field regime. So far, the majority of the tests of GR with GW signals have been carried out following parametrized,…

General Relativity and Quantum Cosmology · Physics 2025-06-17 Félix-Louis Julié , Lorenzo Pompili , Alessandra Buonanno

We comment on the recently introduced Gauss-Bonnet gravity in four dimensions. We argue that it does not make sense to consider this theory to be defined by a set of $D\to 4$ solutions of the higher-dimensional Gauss-Bonnet gravity. We show…

General Relativity and Quantum Cosmology · Physics 2020-08-26 Robie A. Hennigar , David Kubiznak , Robert B. Mann , Christopher Pollack

A modified Einstein-Gauss-Bonnet gravity in four dimensions where the quadratic Gauss-Bonnet term is coupled to a scalar field is considered. The field equations of the model are obtained by variational methods by making use of the…

General Relativity and Quantum Cosmology · Physics 2016-08-30 Hatice Özer , Ahmet Baykal , Özgür Delice

We discuss a new extended gravity model in ordinary $D=4$ spacetime dimensions, where an additional term in the action involving Gauss-Bonnet topological density is included without the need to couple it to matter fields unlike the case of…

General Relativity and Quantum Cosmology · Physics 2018-11-13 Eduardo Guendelman , Emil Nissimov , Svetlana Pacheva

We show that General Relativity (GR) with cosmological constant may be formulated as a rather simple constrained SO(D-1,2) (or SO(D,1))-Yang-Mills (YM) theory. Furthermore, the spin connections of the Cartan-Einstein formulation for GR…

General Relativity and Quantum Cosmology · Physics 2007-05-23 M. Botta Cantcheff

We propose a boundary term to the Einstein-Gauss-Bonnet action for gravity, which is constructed as the dimensional continuation of the Chern-Weil theorem, and such that the extremization of the full action yields the equations of motion…

General Relativity and Quantum Cosmology · Physics 2018-05-16 Nathalie Deruelle , Nelson Merino , Rodrigo Olea

We analyze the observational and theoretical constraints on ``Einstein-aether theory", a generally covariant theory of gravity coupled to a dynamical, unit, timelike vector field that breaks local Lorentz symmetry. The results of a…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Brendan Z. Foster , Ted Jacobson

General relativity (GR) as described in terms of curvature by the Einstein-Hilbert action is dynamically equivalent to theories of gravity formulated in terms of spacetime torsion or non-metricity. This forms what is called the geometrical…

High Energy Physics - Theory · Physics 2024-09-05 Johanna Erdmenger , Bastian Heß , Ioannis Matthaiakakis , René Meyer

In this paper, the generalized second law (GSL) of thermodynamics and entropy is revisited in the context of cosmological models in Gauss-Bonnet gravity with the boundary of the universe is assumed to be enclosed by the dynamical apparent…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Hossein Farajollahi , Amin Salehi

The non zero value of Planck constant $h$ underlies the emergence of several inequalities that must be satisfied in the quantum realm, the most prominent one being Heisenberg Uncertainty Principle. Among these inequalities, Bekenstein bound…

High Energy Physics - Theory · Physics 2021-12-10 Luca Buoninfante , Giuseppe Gaetano Luciano , Luciano Petruzziello , Fabio Scardigli

Classically, unimodular gravity is known to be equivalent to General Relativity (GR), except for the fact that the effective cosmological constant $\Lambda$ has the status of an integration constant. Here, we explore various formulations of…

High Energy Physics - Theory · Physics 2014-11-18 Bartomeu Fiol , Jaume Garriga

In a gedanken experiment in which a box initially containing energy $E$ and entropy $S$ is lowered toward a black hole and then dropped in, it was shown by Unruh and Wald that the generalized second law of black hole thermodynamics holds,…

General Relativity and Quantum Cosmology · Physics 2016-08-25 M. A. Pelath , Robert M. Wald

An outstanding open issue in our quest for physics beyond Einstein is the unification of general relativity (GR) and quantum physics. Loop quantum gravity (LQG) is a leading approach toward this goal. At its heart is the central lesson of…

General Relativity and Quantum Cosmology · Physics 2021-04-12 Abhay Ashtekar , Eugenio Bianchi

Chern-Simons models for gravity are interesting because they provide with a truly gauge-invariant action principle in the fiber-bundle sense. So far, their main drawback has largely been the perceived remoteness from standard General…

High Energy Physics - Theory · Physics 2014-11-18 Fernando Izaurieta , Paul Minning , Alfredo Pérez , Eduardo Rodríguez , Patricio Salgado

In considering alternative higher-order gravity theories, one is liable to be motivated in pursuing models consistent and inspired by several candidates of a fundamental theory of quantum gravity. Indeed, motivations from string/M-theory…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Nadiezhda Montelongo García , Tiberiu Harko , Francisco S. N. Lobo , José P. Mimoso

We present a bouquet of continuity bounds for quantum entropies, falling broadly into two classes: First, a tight analysis of the Alicki-Fannes continuity bounds for the conditional von Neumann entropy, reaching almost the best possible…

Quantum Physics · Physics 2016-09-06 Andreas Winter

In this work we take into consideration a generalization of Gauge Theories based on the analysis of the structural characteristics of Maxwell theory, which can be considered as the prototype of such kind of theories (Maxwell-like). Such…

General Relativity and Quantum Cosmology · Physics 2017-04-03 Germano Resconi , Ignazio Licata , Christian Corda

Based on the view that Einstein's theory can be interpreted as a gauge theory of Lorentz group, we decompose the gravitational connection (the gauge potential of Lorentz group) $\vGm_\mu$ into the restricted connection made of the potential…

General Relativity and Quantum Cosmology · Physics 2011-02-18 Y. M. Cho , S. H. Oh , Sang-Woo Kim

We investigate the $D\rightarrow 4$ limit of the $D$-dimensional Einstein-Gauss-Bonnet gravity, where the limit is taken with $\tilde{\alpha}=(D-4)\, \alpha$ kept fixed and $\alpha$ is the original Gauss-Bonnet coupling. Using the ADM…

General Relativity and Quantum Cosmology · Physics 2020-10-12 Katsuki Aoki , Mohammad Ali Gorji , Shinji Mukohyama