Zobrazeno 1 - 10
of 27
pro vyhledávání: '"Artur Alho"'
Publikováno v:
Physical Review D. 106
A foundational theorem due to Buchdahl states that, within General Relativity (GR), the maximum compactness $\mathcal{C}\equiv GM/(Rc^2)$ of a static, spherically symmetric, perfect fluid object of mass $M$ and radius $R$ is $\mathcal{C}=4/9$. As a c
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a0efae974503b2cba8e24627177b23e6
https://doi.org/10.1103/physrevd.106.l041502
https://doi.org/10.1103/physrevd.106.l041502
Publikováno v:
Physical Review D. 105
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::48f13273cb4a11f5a51ad3f79bda325d
https://doi.org/10.1103/physrevd.105.129903
https://doi.org/10.1103/physrevd.105.129903
Autor:
Simone Calogero, Artur Alho
Publikováno v:
Archive for Rational Mechanics and Analysis. 238:639-669
The existence of static self-gravitating Newtonian elastic balls is proved under general assumptions on the constitutive equations of the elastic material. The proof uses methods from the theory of finite-dimensional dynamical systems and the Euler f
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ecdb84a4eb07313a6d311110ed531b44
https://doi.org/10.1007/s00205-020-01551-1
https://doi.org/10.1007/s00205-020-01551-1
We consider a dynamical systems formulation for models with an exponential scalar field and matter with a linear equation of state in a spatially flat and isotropic spacetime. In contrast to earlier work, which only considered linear hyperbolic fixed
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f39caf32863b1de709a75224e37795b3
We use dynamical systems methods to study quintessence models in a spatially flat and isotropic spacetime with matter and a scalar field with potentials for which $\lambda(\varphi)=-V_{,\varphi}/V$ is bounded, thereby going beyond the exponential pot
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3b31f242adbbbcfc20dd7c43d8888f94
Autor:
Simone Calogero, Artur Alho
Publikováno v:
Communications in Mathematical Physics. 371:975-1004
We study the problem of static, spherically symmetric, self-gravitating elastic matter distributions in Newtonian gravity. To this purpose we first introduce a new definition of homogeneous, spherically symmetric (hyper)elastic body in Euler coordina
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https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1cb50f86a447f7559c421971899c9e1e
https://doi.org/10.1007/s00220-019-03380-0
https://doi.org/10.1007/s00220-019-03380-0
We derive a new \emph{regular} dynamical system on a 3-dimensional \emph{compact} state space describing linear scalar perturbations of spatially flat Robertson-Walker geometries for relativistic models with a minimally coupled scalar field with an e
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::483bd9c9d3a3a8f1e58f1998a3aaf614
http://arxiv.org/abs/2006.00800
http://arxiv.org/abs/2006.00800
Autor:
Simone Calogero, Artur Alho
Publikováno v:
Journal of Geometry and Physics. 120:62-72
We consider a spherically symmetric stellar model in general relativity whose interior consists of a pressureless fluid undergoing microscopic velocity diffusion in a cosmological scalar field. We show that the diffusion dynamics compel the interior
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fe617827bcbb9f4973b322405cdaf439
https://doi.org/10.1016/j.geomphys.2017.05.018
https://doi.org/10.1016/j.geomphys.2017.05.018
We apply a new global dynamical systems formulation to flat Robertson-Walker cosmologies with a massless and massive Yang-Mills field and a perfect-fluid with linear equation of state as the matter sources. This allows us to give proofs concerning th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8b0a63c8a658faf83f69fa4638fb334c
http://arxiv.org/abs/1910.04678
http://arxiv.org/abs/1910.04678
Publikováno v:
Journal of Hyperbolic Differential Equations
Journal of Hyperbolic Differential Equations, World Scientific Publishing, 2019, 16 (02), pp.379-400. ⟨10.1142/S0219891619500140⟩
Journal of Hyperbolic Differential Equations, World Scientific Publishing, 2019, 16 (02), pp.379-400. ⟨10.1142/S0219891619500140⟩
We consider the wave equation, [Formula: see text], in fixed flat Friedmann–Lemaître–Robertson–Walker and Kasner spacetimes with topology [Formula: see text]. We obtain generic blow up results for solutions to the wave equation toward the Big
Externí odkaz:
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https://hal.sorbonne-universite.fr/hal-02967520/document
https://hal.sorbonne-universite.fr/hal-02967520/document