A5091875710- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Particle physics theoretical and experimental studies
- Astrophysical Phenomena and Observations
- Noncommutative and Quantum Gravity Theories
- Relativity and Gravitational Theory
- Quantum Chromodynamics and Particle Interactions
- Astrophysics and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Experimental and Theoretical Physics Studies
- Algebraic and Geometric Analysis
- Advanced Numerical Analysis Techniques
- Neutrino Physics Research
- Geometric Analysis and Curvature Flows
- Quantum chaos and dynamical systems
- Advanced Thermodynamics and Statistical Mechanics
- Dark Matter and Cosmic Phenomena
- Nonlinear Waves and Solitons
- Catalysis and Oxidation Reactions
- Adaptive optics and wavefront sensing
- Stochastic processes and statistical mechanics
- Geomagnetism and Paleomagnetism Studies
- Atomic and Subatomic Physics Research
- Geophysics and Gravity Measurements
Princeton University
2022-2024
Centre National de la Recherche Scientifique
2022-2024
Université Paris Cité
2022-2024
École Normale Supérieure - PSL
2024
Sorbonne Paris Cité
2024
Sorbonne Université
2024
Institut de Physique Théorique
2024
Université Paris Sciences et Lettres
2024
Friedrich Schiller University Jena
2022-2023
Imperial College London
2020-2023
A formalism is presented for the treatment of space-times, which intermediate between a fully covariant approach and spin-coefficient method Newman Penrose. With present formalism, pair null directions only, rather than an entire tetrad, singled out at each point. The concept spin- boost-weighted quantity defined, operating entirely with such quantities. This entails introduction modified differentiation operators, one represents natural extension definition operator ð had been introduced...
The exploration of the universe has recently entered a new era thanks to multi-messenger paradigm, characterized by continuous increase in quantity and quality experimental data that is obtained detection various cosmic messengers (photons, neutrinos, rays gravitational waves) from numerous origins. They give us information about their sources properties intergalactic medium. Moreover, astronomy opens up possibility search for phenomenological signatures quantum gravity. On one hand, most...
We discover that asymptotically safe quantum gravity could predict the top-quark mass. For a broad range of microscopic gravitational couplings, provide an ultraviolet completion for Standard Model by triggering asymptotic freedom in gauge couplings and bottom Yukawa safety top-Yukawa Higgs-quartic coupling. find part this range, difference top mass approximately $170\, \rm GeV$ is generated Higgs determined terms Assuming no new physics below Planck scale, we construct explicit...
A phenomenologically viable theory of quantum gravity must accommodate all observed matter degrees freedom and their properties. Here, we explore whether a toy model the Higgs-Yukawa sector Standard Model is compatible with asymptotically safe gravity. We discuss phenomenological implications our result in context Model. analyze scaling dimension system, find an irrelevant Yukawa coupling at joint gravity-matter fixed point. Further, impact gravity-induced couplings between scalars fermions,...
We highlight how the existence of an ultraviolet completion for interacting Standard-Model type matter puts constraints on viable microscopic dynamics asymptotically safe quantum gravity within truncated Renormalization Group flows. A first constraint -- weak-gravity bound is rooted in destruction scale-invariance system by strong quantum-gravity fluctuations. second arises linking Planck-scale to at electroweak scale. Specifically, we delineate extract a prediction top quark mass from and...
We propose a scenario to retrodict the top and bottom mass Abelian gauge coupling from first principles in microscopic model including quantum gravity. In our approximation, antiscreening quantum-gravity fluctuations induce an asymptotically safe fixed point for hypercharge leading uniquely infrared value that is observationally viable particular choice of gravitational parameters. The unequal numbers quark lead different fixed-point values Yukawa couplings under impact gravity fluctuations....
Abstract Within quantum-gravity approaches and beyond, different mechanisms for singularity resolution in black holes exist. Under a set of assumptions that we spell out detail, these leave their imprint shadow images spherically symmetric holes. We find even current EHT accuracy is sufficient to place nontrivial constraints on the scale new physics within one modified spacetime, if measurement M87* combined with an independent black-hole mass. In other spacetimes, increased required...
General relativity's prediction that all black holes are described by the Kerr metric, irrespective of their size, can now be empirically tested using electromagnetic observations supermassive and gravitational waves from mergers stellar-mass holes. In this work, we focus on side test quantify constraining power very-long-baseline-interferometry (VLBI) emission generated hot gas surrounding We demonstrate how to use lensing bands---annular regions observer's screen critical curve---to...
A direct connection between the spin and conformally weighted functions on sphere geometric objects in Minkowski space is established through isomorphism of conformal group to restricted Lorentz group. It shown that with use these one can duplicate all standard work representations further be used obtain a generalization classical equations motion which internal degrees freedom arise naturally.
We set out to bridge the gap between regular black-hole spacetimes and observations of a shadow by Event Horizon Telescope. explore modifications spinning non-spinning inspired asymptotically safe quantum gravity which features scale dependence Newton coupling. As consequence, predictions our model, such as shape size, depend on one free parameter determining curvature at deviations from General Relativity in. In more general new-physics settings, it can also depart substantially Planck...
Abstract To understand the true nature of black holes, fundamental theoretical developments should be linked all way to observational features holes in their natural astrophysical environments. Here, we take several steps establish such a link. We construct family spinning, regular black-hole spacetimes based on locality principle for new physics and analyze shadow images. identify characteristic image associated regularity (increased compactness relative stretching) (cusps asymmetry) that...
We investigate the linear stability of two known branches spherically-symmetric black holes in Quadratic Gravity. extend previous work on long-wavelength (Gregory-Laflamme) instability Schwarzschild branch to a corresponding non-Schwarzschild branch. In both cases, sets below critical horizon radius at which black-hole intersect. This suggests that classical perturbations enforce lower bound
We study the capabilities of present and future radio very-long-baseline-interferometry arrays to distinguish black holes from horizonless spacetimes. consider an example a spacetime, obtained by overspinning regular hole. Its image is distinct Kerr spacetime due second set photon rings interior shadow. These cannot be directly resolved even next-generation Event Horizon telescope arrays, but instead imprint themselves in horizon-scale images as excess central brightness relative that...
Abstract Negative kinetic energies correspond to ghost degrees of freedom, which are potentially relevance for cosmology, quantum gravity, and high energy physics. We present a novel wide class stable mechanical systems where positive degree freedom interacts with ghost. These theories have Hamiltonians unbounded from above below, integrable, contain free functions. show analytically that their classical motion is bounded all initial data. Moreover, we derive conditions allowing Lyapunov...
Asymptotically safe quantum fluctuations of gravity can uniquely determine the value gauge coupling for a large class grand unified models. In turn, this makes electromagnetic fine-structure constant calculable. The balance and matter results in fixed point running coupling. It is approached as momentum scale lowered transplanckian regime, leading to predicted at Planck scale. precise depends on content model. proportional gravitational fluctuation effects which computational uncertainties...
We propose a scenario with string theory in the deep ultraviolet, an intermediate asymptotically safe scaling regime for gravity and matter, Standard Model infrared. This could provide new perspective to tackle challenges of two models: For instance, gravitational Renormalization Group flow connect negative microscopic positive macroscopic cosmological constant, potentially rendering on anti-de Sitter background observationally viable. Further, unitarity string-theoretic ultraviolet...
We demonstrate that black holes and stars in general relativity can be destabilized by perturbations of non-minimally coupled vector fields. Focusing on static spherically symmetric backgrounds, our analysis shows with sufficiently small mass high densities are subject to ghost or gradient-type instabilities. This holds for a large class vector-tensor theories whenever non-minimal couplings contribute linearized dynamics about state vanishing field applies generalized Proca models have...
Abstract We discuss parameterizations of black-hole spacetimes in and beyond general relativity view their symmetry constraints: within the class axisymmetric, stationary spacetimes, we propose a parameterization that includes non-circular both Boyer–Lindquist as well horizon-penetrating coordinates. show how existing parameterizations, which make additional assumptions (first, circularity; second, hidden constant motion), are included new parameterization. Further, explain why coordinates...
Abstract New physics beyond General Relativity can modify image features of black holes and horizonless spacetimes increase the separation between photon rings. This motivates us to explore synthetic images consisting two thin Our are parameterized by as well relative flux density We perform fits visibility amplitude analyze closure quantities. The current Event Horizon Telescope array cannot detect presence a second ring in region parameters motivated particular new-physics cases. show that...
We present a mechanism which drives Dirac neutrino masses to tiny values along the Renormalization Group flow, starting from an asymptotically safe ultraviolet completion of third generation Standard Model including quantum gravity. At same time, produces mass-splitting between and quark sector also generates mass splitting top bottom quark. The hinges on hypercharges fermions Yukawa coupling, because right-handed is sterile does not carry hypercharge.
We present a numerically stable system of ($3+1$) evolution equations for the nonlinear gravitational dynamics quadratic-curvature corrections to General Relativity (quadratic gravity). also report on numerical implementation these equations. recover well-known linear instability and gather evidence that---aside from said instability---quadratic gravity exhibits physically Ricci-flat subsector. In particular, we demonstrate that Teukolsky-wave perturbations Schwarzschild black hole as well...