A5068643506- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Quantum Electrodynamics and Casimir Effect
- Particle physics theoretical and experimental studies
- Pulsars and Gravitational Waves Research
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Relativity and Gravitational Theory
- Noncommutative and Quantum Gravity Theories
- Computational Physics and Python Applications
- Space Science and Extraterrestrial Life
- Experimental and Theoretical Physics Studies
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Advanced Thermodynamics and Statistical Mechanics
- Gamma-ray bursts and supernovae
- Mechanical and Optical Resonators
- Quantum Mechanics and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum, superfluid, helium dynamics
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Atomic and Molecular Physics
Institut de Physique Théorique
2016-2025
Centre National de la Recherche Scientifique
2016-2025
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2016-2025
Université Paris-Saclay
2016-2025
CEA Paris-Saclay
2016-2025
European Organization for Nuclear Research
2000-2024
Direction des énergies
2023
Institute of Theoretical Physics
2023
École Polytechnique Fédérale de Lausanne
2023
University of Sheffield
2020
We analyze $f(R)$ modifications of Einstein's gravity as dark energy models in the light their connection with chameleon theories. Formulated scalar-tensor theories, theories imply existence a strong coupling scalar field to matter. This would violate all experimental gravitational tests on deviations from Newton's law. Fortunately, matter dependent mass and thin-shell effect allows one alleviate these constraints. The condition also implies restrictions cosmological dynamics As consequence,...
The existence of a light or massive scalar field with coupling to matter weaker than gravitational strength is possible source violation the weak equivalence principle. We use first results on E\"otv\"os parameter by MICROSCOPE experiment set new constraints such fields. For mass smaller $10^{-12}$ eV (i.e. range larger few $10^5$ m) we improve existing one order magnitude $|\alpha|<10^{-11}$ if couples baryon number and $|\alpha|<10^{-12}$ difference between lepton numbers. also consider...
General Relativity and the $\Lambda$CDM framework are currently standard lore constitute concordance paradigm. Nevertheless, long-standing open theoretical issues, as well possible new observational ones arising from explosive development of cosmology last two decades, offer motivation lead a large amount research to be devoted in constructing various extensions modifications. All extended theories scenarios first examined under light consistency, then applied geometrical backgrounds, such...
Long range scalar fields with a coupling to matter appear violate known bounds on gravitation in the solar system and laboratory. This is evaded thanks screening mechanisms. In this short review, we shall present various mechanisms from an effective field theory point of view. We then investigate how they can will be tested laboratory astrophysical cosmological scales.
We explore the prospects for direct detection of dark energy by current and upcoming terrestrial matter experiments. If is driven a new light degree freedom coupled to photons then quanta are predicted be produced in Sun. These free-stream towards Earth where they can interact with Standard Model particles chambers experiments, presenting possibility that these experiments could used test energy. Screening mechanisms, which suppress fifth forces associated particles, necessary feature many...
We investigate the imprints of accretion and dynamical friction on gravitational-wave signals emitted by binary black holes embedded in a scalar dark matter cloud. As key feature this work, we focus fields with repulsive self-interaction that balances against self-gravity To first approximation, phase signal receives extra correction terms at $\ensuremath{-}3\mathrm{PN}$, $\ensuremath{-}4\mathrm{PN}$, $\ensuremath{-}5.5\mathrm{PN}$ orders, relative to prediction vacuum general relativity,...
The environment-dependent dilaton field is a well-motivated candidate for dark energy and naturally arises in the strong coupling limit of string theory. In this article, we present very first experimental constraints on parameters model. For this, employ data obtained from qBounce collaboration Lunar Laser Ranging (LLR) experiment. Furthermore, forecast expected Casimir And Non Newtonian force EXperiment (Cannex) soon to be realised an improved setup. Finally, provide detailed analysis...
We analyze the PVLAS results using a chameleon field whose properties depend on environment. find that, assuming runaway bare potential $V(\ensuremath{\phi})$ and universal coupling to matter, is such that scalar can act as dark energy. Moreover, chameleon-field model compatible with CERN Axion Solar Telescope results, fifth-force experiments, cosmology.
The best laboratory constraints on strongly coupled chameleon fields come not from tests of gravity per se but precision measurements the Casimir force. chameleonic force between two nearby bodies is more akin to a Casimir-like than gravitational one: behaves as an inverse power distance separation surfaces bodies, just does. Additionally, experimental often employ thin metallic sheet shield electrostatic forces; however, this masks any detectable signal due presence field. As result...
New fifth forces have not yet been detected in the laboratory or solar system, hence it is typically difficult to introduce new light scalar fields that would mediate such forces. In recent years has shown a number of non-linear field theories allow for dynamical mechanism, as Vainshtein and chameleon ones, suppresses strength force experimental environments. This known screening, however unclear how common screening within theories. k-essence models are commonly studied examples models,...
The ubiquitous role of light scalar fields in modified gravity models necessitates the introduction screening mechanisms whereby gravitation solar system can be described by General Theory Relativity to an extremely precise level. On larger scales, laws with various phenomelogical consequences. We review status three main when a single field modifies gravity. emphasize qualitative and quantitative differences between subject chameleon Damour–Polyakov on one hand, Vainshtein mechanism other hand.
We study the cosmology of K-mouflage theories at background level. show that effects scalar field are suppressed high matter density in early Universe and only play a role late time where deviations Hubble rate from its $\Lambda$-CDM counterpart can be order five percent for redshifts $1 \lesssim z 5$. Similarly, we find equation state cross phantom divide recent past even diverge when effective energy goes negative subdominant compared to matter, preserving positivity squared rate. These...
We study the formation of solitons inside scalar-field dark matter halos with a non-polynomial self-interaction potential. consider potential that is quartic in scalar field low-density regime but saturates at large densities. This mimics behaviour axion monodromy potentials. concentrate on semi-classical regime, where de Broglie wavelength much smaller than size system. find depending strength and scale self-interactions, system can form Thomas-Fermi type (dominated by self-interactions) or...
Recent high-precision measurements of the CMB anisotropies performed by BOOMERanG and MAXIMA-1 experiments provide an unmatched set data allowing us to probe different cosmological models. Among these scenarios, motivated recent luminosity distance versus redshift relation for type Ia supernovas, is quintessence hypothesis. It consists assuming that acceleration Universe due a scalar field whose final evolution insensitive initial conditions. Within this framework we investigate...
It was recently argued that the observed PVLAS anomaly can be explained by chameleon field theories in which large deviations from Newton's law avoided. Here we present predictions for dichroism and birefringence induced vacuum a magnetic these models. We show particles behave very differently standard axionlike (ALPs). find that, unlike ALPs, are confined within experimental setup. As consequence, is always bigger than PVLAS-type experiments.
We calculate the shift in atomic energy levels induced by presence of a scalar field which couples to matter and photons. find that combination measurements can be used probe both these couplings independently. A new stringent bound on coupling springs from precise measurement $1s$ $2s$ level difference hydrogen atom, while photons is essentially constrained Lamb shift. For range masses constraints are not as those fifth force experiments or optical astrophysical laboratory measurements....
We consider different methods to probe the chameleon scalar field with slow neutrons. Chameleons modify potential of bouncing neutrons over a flat mirror in terrestrial gravitational field. This induces shift energy levels which could be detected current experiments like GRANIT. between parallel plates have profile is bubblelike and would phase interferometric experiments. show that this new method detection competitive neutron one, hopefully providing an efficient chameleons when strongly...
We study the effects of screened modified gravity $f(R)$, dilaton and symmetron types on structure formation, from quasi-linear to non-linear regime, using semi-analytical methods. For such models, where range new scalar field is typically within Mpc below in cosmological context, techniques are required understand deviations power spectrum matter density contrast compared $\Lambda$-CDM template. This nowadays commonly tackled extensive N-body simulations. Here we present results combining...
We study structure formation in K-mouflage cosmology whose main feature is the absence of screening effect on quasilinear scales. show that growth at linear level affected by both a new time dependent Newton constant and friction term which depend background evolution. These combine with modified evolution to change rate up ten percent since $z\sim 2$. At one loop level, we find nonlinearities models are mostly due matter dynamics scalar perturbations can be treated tree level. also...
Dark sectors lying beyond the Standard Model and containing sub-GeV particles which are bilinearly coupled to nucleons would induce quantum forces of Casimir-Polder type in ordinary matter. Such new can be tested by a variety experiments over many orders magnitude. We provide generic interpretation these experimental searches apply it sample from dark scalars behaving as $1/{r}^{3}$, $1/{r}^{5}$, $1/{r}^{7}$ at short range. The landscape constraints on such differs one modified gravity with...
Five-dimensional braneworld constructions in anti-de Sitter space naturally lead to dark sector scenarios which parts of the vanish at high 4d momentum or temperature. In language modified gravity, such feature implies a new mechanism for hiding light scalars, as well possibility UV-completing chameleon-like effective theories. matter phenomenology, high-energy behaviour mediator changes observational complementarity. A multitude signatures---including exotic ones---are present from...
We analyse the speed of gravitational waves in coupled Galileon models with an equation state ωϕ=−1 now and a ghost-free Minkowski limit. find that propagate much faster than light unless these are small perturbations cubic Galileons energy density is sub-dominant to dominant cosmological constant. In this case, binary pulsar bounds on can be satisfied close -1 when coupling matter coefficient term Lagrangian related. This severely restricts allowed behaviour we forced conclude stable limit...
We compute bounds on screened scalar field theories from hydrogenlike systems. New light fields generically have a direct coupling to matter. Such is strongly constrained by myriad experimental measurements. However, certain possess screening mechanism that allows the effects of this weaken dynamically, and evade many such bounds. perturbations energy levels systems due fields. then use result in two ways. First, we hydrogen spectroscopy, finding significantly weaker than been reported...
We explore an extension of the standard $Λ$CDM model by including interaction between neutrinos and dark matter, making use ground based telescope data Cosmic Microwave Background (CMB) from Atacama Cosmology Telescope (ACT). An indication for a non-zero coupling matter (both assuming temperature independent $T^2$ dependent cross-section) is obtained at 1$σ$ level coming ACT CMB alone when combined with Planck Baryon Acoustic Oscillations (BAO) measurements. This result confirmed both fixing...