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Current constraints on gravity are relatively weak on galactic and intergalactic scales. Screened modified gravity models can exhibit complex behaviour there without violating stringent tests of gravity within our Solar System. They might…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-15 Aneesh P. Naik , Ewald Puchwein , Anne-Christine Davis , Christian Arnold

Chameleon gravity is an example of a model that gives rise to interesting phenomenology on cosmological scales while simultaneously possessing a screening mechanism, allowing it to avoid solar system constraints. Such models result in…

General Relativity and Quantum Cosmology · Physics 2022-06-15 Andrius Tamosiunas , Chad Briddon , Clare Burrage , Weiguang Cui , Adam Moss

We lay out the frameworks to numerically study the structure formation in both linear and nonlinear regimes in general dark-matter-coupled scalar field models, and give an explicit example where the scalar field serves as a dynamical dark…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 Baojiu Li , Hongsheng Zhao

Laboratory experiments on gravitation are usually performed with objects of constant density, so that the analysis of the forces concerns only the geometry of their shape. In an ideal experiment, the shapes of the constituent parts will be…

General Relativity and Quantum Cosmology · Physics 2007-05-23 John W. Barrett

We investigate the non-linear evolution of matter perturbations in $f(R)$ models with the Chameleon screening mechanism. The novel feature of our investigation is an iterative solution for the non-linear equation for the scalar field $\chi…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-30 Sharvari Nadkarni-Ghosh , Tanush Reddy Vaka

The accelerated expansion of the universe motivates a wide class of scalar field theories that modify gravity on large scales. In regions where the weak field limit of General Relativity has been confirmed by experiment, such theories need…

The potential harms of the under-representation of minorities in training data, particularly in multi-modal settings, is a well-recognized concern. While there has been extensive effort in detecting such under-representation, resolution has…

Machine Learning · Computer Science 2024-12-03 Mahdi Erfanian , H. V. Jagadish , Abolfazl Asudeh

The practice of collider physics typically involves the marginalization of multi-dimensional collider data to uni-dimensional observables relevant for some physics task. In any cases, such as classification or anomaly detection, the…

High Energy Physics - Phenomenology · Physics 2026-03-26 Arindam Bhattacharya , Katherine Fraser , Matthew D. Schwartz

In a previous paper [Phys. Rev. D 97, 104044 (2018)] we pointed out some shortcomings of the standard approach to chameleon theories consisting in treating the small bodies used to test the weak equivalence principle (WEP) as test…

General Relativity and Quantum Cosmology · Physics 2019-04-22 Lucila Kraiselburd , Susana J. Landau , Marcelo Salgado , Daniel Sudarsky , Héctor Vucetich

A frame is a generalization of a basis of a vector space to a redundant overspanning set whose vectors are linearly dependent. Frames find applications in signal processing and quantum information theory. We present a genetic algorithm that…

Computational Physics · Physics 2025-08-13 Sebastián Roca-Jerat , Juan Román-Roche

Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-22 Lucas Lombriser , Fergus Simpson , Alexander Mead

Modified theories of gravity provide us with a unique opportunity to generate innovative tests of gravity. In Chameleon f(R) gravity, the gravitational potential differs from the weak-field limit of general relativity (GR) in a mass…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-26 Alejo Stark , Christopher J. Miller , Nicholas Kern , Daniel Gifford , Gong-Bo Zhao , Baojiu Li , Kazuya Koyama , Robert C. Nichol

Screening mechanisms allow light scalar fields to dynamically avoid the constraints that come from our lack of observation of a long-range fifth force. Galactic scale tests are of particular interest when the light scalar is introduced to…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-01 Clare Burrage , Bradley March , Aneesh P. Naik

Screened scalars are ubiquitous in many dark-sector models. They give rise to non-trivial fifth forces whilst evading experimental constraints through density-dependent screening mechanisms. We propose equipping a 10\,m-scale long-baseline…

High Energy Physics - Phenomenology · Physics 2025-11-14 Hannah Banks , John Carlton , Benjamin Elder , Thomas Hird , Christopher McCabe

Chameleons are a well motivated scalar field that might explain the observed late time accelerated expansion of the universe. Chameleons possess the interesting property that their mass, and hence interaction range, is dependent on the…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-27 Robert Poltis

We investigate the dependence of the Vainshtein screening mechanism on the cosmic web morphology of both dark matter particles and halos as determined by ORIGAMI. Unlike chameleon and symmetron screening, which come into effect in regions…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-04 Bridget Falck , Kazuya Koyama , Gong-bo Zhao , Baojiu Li

We present a framework for embedding scalar-tensor models of screened modifed gravity such as chameleons, symmetrons and environmental dilatons into global supersymmetry. This achieved by secluding the dark sector from both the observable…

High Energy Physics - Theory · Physics 2015-06-12 Philippe Brax , Anne-Christine Davis , Jeremy Sakstein

In this article we discuss some aspects of solar physics from the standpoint of the so-called chameleon fields (i.e. quantum fields, typically scalar, where the mass is an increasing function of the matter density of the environment).…

High Energy Physics - Phenomenology · Physics 2016-04-05 Andrea Zanzi , Barbara Ricci

In chameleon dark energy models, local gravity constraints tend to rule out parameters in which observable cosmological signatures can be found. We study viable chameleon potentials consistent with a number of recent observational and…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-24 Radouane Gannouji , Bruno Moraes , David F. Mota , David Polarski , Shinji Tsujikawa , Hans A. Winther

It is widely believed that the screening mechanism is an essential feature for the modified gravity theory. Although this mechanism has been examined thoroughly in the past decade, their analyses are based on the classical configuration of…

General Relativity and Quantum Cosmology · Physics 2019-10-03 Taishi Katsuragawa , Shinya Matsuzaki , Eibun Senaha