A5026056355- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Quantum Electrodynamics and Casimir Effect
- Relativity and Gravitational Theory
- Noncommutative and Quantum Gravity Theories
- Gamma-ray bursts and supernovae
- Advanced Differential Geometry Research
- Experimental and Theoretical Physics Studies
- Particle physics theoretical and experimental studies
- Advanced Mathematical Physics Problems
- Geophysics and Sensor Technology
- Geophysics and Gravity Measurements
- Nonlinear Waves and Solitons
- Radiative Heat Transfer Studies
- Mechanical and Optical Resonators
- Spectral Theory in Mathematical Physics
- Advanced X-ray Imaging Techniques
- Numerical methods in inverse problems
- Spanish Philosophy and Literature
- Scientific Measurement and Uncertainty Evaluation
- Radioactive Decay and Measurement Techniques
- Optical Network Technologies
- Advanced Fiber Optic Sensors
Centro Brasileiro de Pesquisas Físicas
2015-2024
University College Dublin
2015-2024
Leipzig University
2022-2024
Laboratoire Univers et Théories
2022-2023
Université Paris Cité
2022-2023
Université Paris Sciences et Lettres
2022-2023
Centre National de la Recherche Scientifique
2022-2023
Dublin City University
2009-2012
Perimeter Institute
2012
University of Guelph
2012
The open question of whether a black hole can become tidally deformed by an external gravitational field has profound implications for fundamental physics, astrophysics and gravitational-wave astronomy. Love tensors characterize the tidal deformability compact objects such as astrophysical (Kerr) holes under static field. We prove that all vanish identically Kerr in nonspinning limit or axisymmetric perturbation. In contrast to this result, we show are generically nonzero spinning hole....
Spin-weighted spheroidal harmonics are useful in a variety of physical situations, including light scattering, nuclear modeling, signal processing, electromagnetic wave propagation, black hole perturbation theory four and higher dimensions, quantum field curved space-time studies D-branes. We first review analytic numerical calculations their eigenvalues, eigenfunctions filling gaps the existing literature when necessary. Then we compute angular dependence spin-weighted corresponding to...
The open question of whether a Kerr black hole can become tidally deformed or not has profound implications for fundamental physics and gravitational-wave astronomy. We consider embedded in weak slowly varying, but otherwise arbitrary, multipolar tidal environment. By solving the static Teukolsky equation gauge-invariant Weyl scalar $\psi_0$, by reconstructing corresponding metric perturbation an ingoing radiation gauge, general harmonic index $\ell$, we compute linear response to field....
We show that the horizon instability of extremal Kerr black hole is associated with a singular branch point in Green function at superradiant bound frequency. study generic initial data supported away from and find an enhanced growth rate due to nonaxisymmetric modes. The controlled by conformal weight $h$ each mode. speculate on connections near-extremal holes holographic duality.
LISA, the Laser Interferometer Space Antenna, will usher in a new era gravitational-wave astronomy. As first anticipated space-based detector, it expand our view to millihertz sky, where spectacular variety of interesting sources abound: from millions ultra-compact binaries Galaxy, mergers massive black holes at cosmological distances; beginnings inspirals that venture into ground-based detectors' death spiral compact objects holes, and many between. Central realising LISA's discovery...
An important feature of Schwarzschild spacetime is the presence orbiting null geodesics and caustics. Their implies strong gravitational lensing effects for matter radiation, i.e., excitations quantum fields. Here, we raise question whether manifests itself also in vacuum fields, namely by distribution entanglement. To explore this possibility, use method entanglement harvesting, where initially unentangled localized systems are temporarily coupled to field at different locations. We find...
We present a numerical calculation of the expectation value quantum angular-momentum current flux density for scalar field in Unruh state near inner horizon Kerr--de Sitter black hole. Our results indicate that this diverges as ${V}_{\ensuremath{-}}^{\ensuremath{-}1}$ suitable Kruskal coordinate such ${V}_{\ensuremath{-}}=0$ at horizon. Depending on parameter values and hole we consider, depending polar angle (latitude), can have different signs. In extremal cases considered, average angular...
Accurate modeling of gravitational wave emission by extreme-mass ratio inspirals is essential for their detection the LISA mission. A leading perturbative approach involves calculation self-force acting upon smaller orbital body. In this work, we present first application Poisson-Wiseman-Anderson method ``matched expansions'' to compute on a point particle moving in curved spacetime. The employs two expansions Green function, which are, respectively, valid ``quasilocal'' and ``distant past''...
We study a quantum fermion field on background nonextremal Kerr black hole. discuss the definition of standard hole states (Boulware, Unruh, and Hartle-Hawking), focussing particularly differences between fermionic bosonic theory. Since all modes (both particle antiparticle) have positive norm, there is much greater flexibility in how are defined compared with case. In particular, we able to define candidate Boulware-like state, empty at both past future null infinity, Hartle-Hawking-like...
Quasinormal modes are characteristic oscillatory that control the relaxation of a perturbed physical system back to its equilibrium state. In this work, we calculate QNM frequencies and angular eigenvalues Kerr--de Sitter black holes using novel method based on conformal field theory. The spin-field perturbation equations background spacetime essentially reduce two Heun's equations, one for radial part part. We use accessory parameter expansion equation, obtained via isomonodromic...
Rotating or charged classical black holes in isolation possess a special surface their interior, the Cauchy horizon, beyond which evolution of spacetime (based on equations General Relativity) ceases to be deterministic. In this work, we study effect quantum massless scalar field horizon inside rotating (Kerr) hole that is evaporating via emission Hawking radiation (corresponding being Unruh state). We calculate flux components (in Eddington coordinates) renormalized stress-energy tensor as...
Rotating and/or charged black hole spacetimes possess a Cauchy horizon, beyond which Einstein's equations of General Relativity cease to be deterministic. This led the formulation Strong Cosmic Censorship conjecture that such horizons become irregular under field perturbations. We consider linear perturbations rotating and electrically-charged (Kerr-Newman-de Sitter) holes in universe with positive cosmological constant. By calculating quasinormal modes for scalar fermion fields, we provide...
The motion of a small compact object in curved background spacetime deviates from geodesic due to the action its own field, giving rise self-force. This self-force may be calculated by integrating Green function for wave equation over past worldline object. We compute this way case scalar charge Schwarzschild spacetime, making use semi-analytic method matched expansions. Inside local neighbourhood object, uses Hadamard form order render regularization trivial. Outside neighbourhood, we...
A compact object moving in curved spacetime interacts with its own gravitational field. This leads to both dissipative and conservative corrections the motion, which can be interpreted as a self-force acting on object. The original formalism describing this relied heavily Green function of linear differential operator that governs perturbations. However, because global calculation functions nontrivial black-hole spacetimes has been an open problem until recently, alternative methods were...
We analytically investigate backreaction by a quantum scalar field on two rotating Bañados-Teitelboim-Zanelli (BTZ) geometries: that of black hole and naked singularity. In the former case, we explore effects various regions relevance for space-time. find lead to growth both event horizon radius ergosphere, reduction angular velocity, compared unperturbed values. Furthermore, they give rise formation curvature singularity at Cauchy show no evidence appearance superradiant instability. case...
We study the quantum channel between two localized first-quantized systems that communicate in $3+1$ dimensional Schwarzschild spacetime via a field. analyze information carrying capacity of direct and black hole-orbiting null geodesics as well timelike contributions arise because strong Huygens principle does not hold on background. find, particular, nondirect-null contributions, which do possess an analog Minkowski spacetime, can dominate over contributions. cover cases both geodesic...
We study the dynamics of a hierarchical three-body system in general-relativistic regime: an extreme mass-ratio inner binary under tidal influence external body. The consists central Schwarzschild black hole and compact test body moving around it (outer binary). discover three types effects on orbit First, angular moment precesses momentum outer binary. Second, field drives "transient resonance" when radial azimuthal frequencies are commensurate with each other. In contrast resonances driven...
We investigate semiclassical backreaction on a conical naked singularity space-time with negative cosmological constant in (2+1)-dimensions. In particular, we calculate the renormalized quantum stress-energy tensor for conformally coupled scalar field such space-time. then obtain backreacted metric via Einstein equations. show that, regime where approximation can be trusted, dresses an event horizon, thus enforcing cosmic censorship.
We analytically investigate the pertubative effects of a quantum conformally-coupled scalar field on rotating (2+1)-dimensional black holes and naked singularities. In both cases we obtain quantum-backreacted metric analytically. hole case, explore corrections different regions relevance for geometry. find that lead to growth event horizon ergosphere, as well reduction angular velocity compared their corresponding unperturbed values. Quantum also give rise formation curvature singularity at...
Postadiabatic models of extreme- and intermediate-mass-ratio inspirals will require calculations second-order gravitational self-force effects in the spacetime a spinning, Kerr black hole. We take step toward such by implementing recently formulated Teukolsky puncture scheme with Green-Hollands-Zimmerman metric reconstruction [Classical Quantum Gravity 39, 015019 (2022)]. This eliminates critical obstacle gauge singularities that arise standard ``no-string'' reconstruction. Our first...