A5069311962- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Noncommutative and Quantum Gravity Theories
- Geophysics and Gravity Measurements
- Gamma-ray bursts and supernovae
- Numerical methods for differential equations
- High-pressure geophysics and materials
- Algebraic and Geometric Analysis
- Quantum Electrodynamics and Casimir Effect
- Computational Physics and Python Applications
- Astrophysical Phenomena and Observations
- Atomic and Subatomic Physics Research
- Astro and Planetary Science
- Physics of Superconductivity and Magnetism
- Relativity and Gravitational Theory
- Mathematical and Theoretical Analysis
- Nonlinear Waves and Solitons
- Meteorological Phenomena and Simulations
- Advanced Mathematical Physics Problems
- Fluid Dynamics and Turbulent Flows
- Computational Fluid Dynamics and Aerodynamics
- Advanced Differential Geometry Research
Goethe University Frankfurt
2025
National and Kapodistrian University of Athens
2008-2023
Friedrich Schiller University Jena
2022-2023
University of Warsaw
2019
Max Planck Institute for Gravitational Physics
2014-2017
Max Planck Society
2014-2015
University of Otago
2012-2013
Institute of Nuclear and Particle Physics
2008-2010
University of Thessaly
2008
Technological Educational Institute of Central Greece
2008
Abstract We present the second data release of gravitational waveforms from binary neutron star (BNS) merger simulations performed by Computational Relativity ( CoRe ) collaboration. The current database consists 254 different BNS configurations and a total 590 individual numerical-relativity using various grid resolutions. released waveform contain strain Weyl curvature multipoles up to <?CDATA $\ell = m 4$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
In this paper we demonstrate for the first time that it is possible to solve numerically Cauchy problem linearisation of general conformal field equations near spacelike infinity, which only well-defined in Friedrich's cylinder picture. We have restricted ourselves here "core" - spin-2 system propagating on Minkowski space. compute numerical solutions various classes initial data, do convergence tests and also compare exact solutions. choose data intentionally violate smoothness conditions...
The well-known BTZ black hole solution of ($2+1$) Einstein's gravity, in the presence a cosmological constant, is treated both at classical and quantum level. Classically, imposition two manifest local Killing fields geometry level full action results minisuperspace constraint with radial coordinate playing role independent dynamical variable. Noether symmetries this reduced are then shown to completely determine space, without any further need solve equations motion. At mechanical level,...
This paper deals, both analytically and numerically, with the problem of taking into account spatial infinity during evolution linearized gravitational field from past to future null infinity. Generalized conformal equations about a Minkowski background are used.
Numerical relativity simulations are the only way to calculate exact gravitational waveforms from binary neutron star mergers and design templates for gravitational-wave astronomy. The accuracy of these numerical calculations is critical in quantifying tidal effects near merger that currently one main sources uncertainty waveforms. In this work, we explore use an entropy-based flux-limiting scheme high-order, convergent spacetimes. effectively tracks stellar surface physical shocks using...
We present a novel implicit numerical implementation of the parabolic-hyperbolic formulation constraints general relativity. The proposed method is unconditionally stable, has advantage not requiring imposition any boundary conditions in strong field regime, and offers holistic (all inclusive) approach to construction single binary black hole initial data. new solver extensively tested against known exact solutions used construct data for several configurations.
We describe a numerical method to construct Cauchy data extending space-like infinity based on Corvino's (2000) gluing method. Adopting the setting of Giulini and Holzegel (2005), we restrict ourselves here vacuum axisymmetric spacetimes glue Schwarzschildean end Brill–Lindquist describing two non-rotating black holes. Our implementation is pseudo-spectral methods carry out extensive convergence tests check validity our results. also investigate dependence total ADM mass details construction.
The canonical analysis and subsequent quantization of the (2+1)-dimensional action pure gravity plus a cosmological constant term is considered, under assumption existence one spacelike Killing vector field.The proper imposition quantum analogues two linear (momentum) constraints reduces an initial collection state vectors, consisting all smooth functionals components (and/or their derivatives) spatial metric, to particular scalar functionals.The demand that midi-superspace metric (inferred...
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We construct numerically time-symmetric initial data that are Schwarzschildean at spatial infinity and Brill-Lindquist in the interior. The transition between these two sets takes place along a finite gluing region equipped with an axisymmetric Brill wave metric. construction is based on application of Corvino's method using waves due to Giulini Holzegel. Here, we use function includes simple angular dependence. also investigate dependence ADM mass our details procedure.
The construction of high-resolution shock-capturing schemes is vital in producing highly accurate gravitational waveforms from neutron star binaries. entropy based flux limiting (EFL) scheme able to perform fast converging binary merger simulations reaching up fourth-order convergence the waveform phase. Here, we extend applicability EFL method beyond special/general relativistic hydrodynamics scalar conservation laws and show how treat systems without a thermodynamic entropy. This an...
The construction of high-resolution shock-capturing schemes is vital in producing highly accurate gravitational waveforms from neutron star binaries. entropy based flux limiting (EFL) scheme able to perform fast converging binary merger simulations reaching up fourth-order convergence the waveform phase. In these results EFL method was used only dynamical evolution initial data constructed with Lorene library. Here, we extend use eccentricity reduced for binaries and present several new BNS...
The conditional symmetries of the reduced Einstein–Hilbert action emerging from a static, spherically symmetric geometry are used as supplementary conditions on wave function. Based their integrability conditions, only one three existing can be consistently imposed, while unique Casimir invariant, being product remaining two symmetries, is calculated possible second condition This quadratic integral motion identified with reparametrization generator, an implication uniqueness dynamical...
COFFEE (ConFormal Field Equation Evolver) is a Python package primarily developed to numerically evolve systems of partial differential equations over time using the method lines. It includes variety integrators and finite differencing stencils with summation-by-parts property, as well pseudo-spectral functionality for angular derivatives spin-weighted functions. Some additional capabilities include being MPI-parallelisable on different geometries, HDF data output post processing scripts...
Linear perturbations on Minkowski space are used to probe numerically the remote region of an asymptotically flat space-time close spatial infinity. The study is undertaken within framework Friedrich's conformal field equations and corresponding representation infinity as a cylinder. system under consideration (linear) zero-rest-mass equation for spin-2 field. spherical symmetry underlying background decompose into separate non-interacting multipoles. It demonstrated that it possible reach...
Gravitational wave astronomy pipelines rely on template waveform models for searches and parameter estimation purposes. For coalescing binary neutron stars (BNS), such need to accurately reproduce numerical relativity (NR) up merger, in order provide robust estimate of the stars' equation state - dependent parameters. In this work we present an improved version Effective One Body (EOB) model $\tt TEOBResumS$ gravitational waves from BNS systems. Building upon recent post-Newtonian...
A proposal is put forward which enables the canonical quantization of a family axially symmetric geometries in 2+1 dimensions and corresponding spherically 3+1 dimensions. The consists particular renormalization assumption an accompanying requirement results Wheeler-DeWitt equation based on renormalized manifold parametrized by three smooth scalar functionals. aforementioned analytically solved for both case.
A proposal is put forward which enables the canonical quantization of a family spherically symmetric geometries in 3+1 dimensions. The consists particular renormalization Assumption and an accompanying Requirement results Wheeler– DeWitt equation based on renormalized manifold parametrized by three smooth scalar functionals. aforementioned analytically solved for case.