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The cosmological relaxation mechanism proposed in [1] allows for a dynamically generated large separation between the weak scale and a theory cutoff, using a sharp change of theory behaviour upon crossing the limit between unbroken and…

High Energy Physics - Phenomenology · Physics 2016-02-17 Oleksii Matsedonskyi

This paper invokes a new mechanism for reducing a coupled system of fields (including Einstein's equations without a cosmological constant) to equations that possess solutions exhibiting characteristics of immediate relevance to current…

General Relativity and Quantum Cosmology · Physics 2019-11-05 Robin W. Tucker , Timothy J. Walton , Manuel Arrayás , José L. Trueba

We study entanglement entropy for regions with a singular boundary in higher dimensions using the AdS/CFT correspondence and find that various singularities make new universal contributions. When the boundary CFT has an even spacetime…

High Energy Physics - Theory · Physics 2015-06-05 Robert C. Myers , Ajay Singh

We present an approach to cosmological perturbations based on a covariant perturbative expansion between two worldlines in the real inhomogeneous universe. As an application, at an arbitrary order we define an exact scalar quantity which…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Kari Enqvist , Janne Hogdahl , Sami Nurmi , Filippo Vernizzi

We consider here a spherically symmetric but inhomogeneous universe filled with a massless scalar field. The model obeys two constraints. The first one is that the gradient of the scalar field is timelike everywhere. The second constraint…

General Relativity and Quantum Cosmology · Physics 2011-04-20 Swastik Bhattacharya , Pankaj S. Joshi , Ken-ichi Nakao

This article summarizes the proposal to address the cosmological constant problem within the framework of supersymmetric large extra dimensions (SLED). The proposed mechanism is described, emphasizing the relaxation mechanism which ensures…

High Energy Physics - Phenomenology · Physics 2007-05-23 C. P. Burgess

This is the first paper in a series aimed to implement boundary conditions consistent with the constraints' propagation in 3D numerical relativity. Here we consider spherically symmetric black hole spacetimes in vacuum or with a minimally…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Gioel Calabrese , Luis Lehner , Manuel Tiglio

We give evidence that fully supersymmetric Anti-de Sitter vacua of extended supergravity with a residual gauge group containing an abelian factor cannot be scale separated as a consequence of the weak gravity conjecture. We prove this for…

High Energy Physics - Theory · Physics 2022-06-22 Niccolò Cribiori , Gianguido Dall'Agata

We give evidence that supersymmetric anti-de Sitter vacua of five-dimensional supergravity cannot be scale separated as a consequence of quantum gravity constraints, such as the weak gravity conjecture or the species scale. We show this in…

High Energy Physics - Theory · Physics 2023-06-13 Niccolò Cribiori , Carmine Montella

We study the constraints of spacetime supersymmetry for perturbative three- and two-dimensional Minkowski vacua of the critical heterotic string. Assuming a standard RNS construction of the spacetime supersymmetry generators and a compact…

High Energy Physics - Theory · Physics 2018-07-04 Ilarion V. Melnikov , Ruben Minasian , Savdeep Sethi

Motivated by the electroweak hierarchy problem, we consider theories with two extra dimensions in which the four-dimensional scalar fields are components of gauge boson in full space, namely the Gauge-Higgs unification framework. We briefly…

High Energy Physics - Phenomenology · Physics 2007-12-13 D. Hernandez , S. Rigolin , M. Salvatori

A unique description of the Big Crunch-Big Bang transition is given at the classical gravity level, along with a complete set of homogeneous, isotropic, analytic solutions in scalar-tensor cosmology, with radiation and curvature. All…

High Energy Physics - Theory · Physics 2012-09-07 Itzhak Bars

The first part of this review tries to provide a self-contained view of supersymmetry breaking from the bottom-up perspective. We thus describe N=1 supersymmetry in four dimensions, the Standard Model and the MSSM, with emphasis on the…

High Energy Physics - Theory · Physics 2026-02-25 E. Dudas , J. Mourad , A. Sagnotti

Isotropic models in loop quantum cosmology allow explicit calculations, thanks largely to a completely known volume spectrum, which is exploited in order to write down the evolution equation in a discrete internal time. Because of genuinely…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Martin Bojowald

We study the scalar curvature $R$ of the vector moduli space of 5d $\mathcal{N}=1$ supergravities, obtained by compactifying M-theory on a Calabi--Yau three-fold. We find that $R$ can only diverge at points where some gauge interactions go…

High Energy Physics - Theory · Physics 2026-03-02 Alejandro Blanco , Fernando Marchesano , Luca Melotti

It is shown that the cosmological singularity in isotropic minisuperspaces is naturally removed by quantum geometry. Already at the kinematical level, this is indicated by the fact that the inverse scale factor is represented by a bounded…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald

In the current review, we provide a summary of the recent progress made in the cosmological aspect of extra-dimensional Lovelock gravity. Our review covers a wide variety of particular model/matter source combinations:…

General Relativity and Quantum Cosmology · Physics 2024-12-03 Sergey Pavluchenko

We discuss the existence of scaling solutions for multicenter black hole configurations. One of the central results is the equivalence between the existence of two centered scaling solutions and the holographic entropy bound. This…

High Energy Physics - Theory · Physics 2012-03-22 Bram Gaasbeek

Resolving the tension between quantum superpositions and the uniqueness of the classical world is a major open problem. One possibility, which is extensively explored both theoretically and experimentally, is that quantum linearity breaks…

Quantum Physics · Physics 2011-01-27 Angelo Bassi , Dirk-Andre' Deckert , Luca Ferialdi

We examine Bousso's covariant entropy bound conjecture in the context of radiation filled, spatially flat, Friedmann-Robertson-Walker models. The bound is violated near the big bang. However, the hope has been that quantum gravity effects…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Abhay Ashtekar , Edward Wilson-Ewing