Search results for: Marek Szydłowski

Items from 1 to 20 out of 86 results

article

Czy fizyczne teorie efektywne są wiarygodną strategią osiągnięcia teorii finalnej?

Marek Szydłowski, Paweł Tambor

Zagadnienia Filozoficzne w Nauce > 2020 > 68 > 79-116

The paper presents the methodology of effective theories as a strategy used in the process of development of modern physics to reach a final theory. We present the definition and characteristic features of an effective theory, as well as the answer to the question of whether and what kind of scenario of reaching a final theory is realized by contemporary physics. We argue that the process of development...

article

Bifurcations in Ratra–Peebles quintessence models and their extensions

Franciszek Humieja, Marek Szydłowski

The European Physical Journal C > 2019 > 79 > 9 > 1-20

We have used the dynamical system approach in order to investigate the dynamics of cosmological models of the flat Universe with a non-minimally coupled canonical and phantom scalar field and the Ratra–Peebles potential. Applying methods of the bifurcation theory we have found three cases for which the Universe undergoes a generic evolution emerging from either the de Sitter or the static Universe...

article

Metoda wyznaczania trajektorii w otoczeniu równowagi długookresowej w neoklasycznych modelach egzogenicznego wzrostu gospodarczego

Adam Krawiec, Aleksander Stachowski, Marek Szydłowski

Przegląd Statystyczny > 2018 > 65 > 4 > 394-421

article

Singularities in particle-like description of FRW cosmology

Marek Szydłowski, Aleksander Stachowski

The European Physical Journal C > 2018 > 78 > 7 > 1-12

In this paper, we apply the method of reducing the dynamics of FRW cosmological models with a barotropic form of the equation of state to the dynamical system of the Newtonian type to detect the finite scale factor singularities and the finite-time singularities. In this approach all information concerning the dynamics of the system is contained in a diagram of the potential function V(a) of the scale...

article

Simple cosmological model with inflation and late times acceleration

Marek Szydłowski, Aleksander Stachowski

The European Physical Journal C > 2018 > 78 > 3 > 1-9

In the framework of polynomial Palatini cosmology, we investigate a simple cosmological homogeneous and isotropic model with matter in the Einstein frame. We show that in this model during cosmic evolution, early inflation appears and the accelerating phase of the expansion for the late times. In this frame we obtain the Friedmann equation with matter and dark energy in the form of a scalar field...

article

Swoistość ontologiczna i epistemologiczna kosmologii jako nauki o Wszechświecie

Adam Krawiec, Marek Szydłowski, Paweł Tambor

Filozofia i nauka. Studia filozoficzne i interdyscyplinarne > 2018 > 6 > 149-174

W pracy charakteryzujemy swoistość, tj. wyjątkowość kosmologii współczesnej rozumianej jako fizyka Wszechświata. Swoistość ta przejawia się w stosunku do samego przedmiotu badań oraz w stosunku do sposobów zdobywania wiedzy o Wszechświecie, w tym także metod stosowanych do rozwiązywania problemów. Twierdzimy, że kosmologia jest odmienna od standardowej praktyki badawczej fizyki współczesnej (odmienność...

article

Swoistość ontologiczna i epistemologiczna kosmologii jako nauki o Wszechświecie

Adam Krawiec, Marek Szydłowski, Paweł Tambor

Filozofia i Nauka > 2018 > 6 > 149-174

article

Quantum mechanical look at the radioactive-like decay of metastable dark energy

Marek Szydłowski, Aleksander Stachowski, Krzysztof Urbanowski

The European Physical Journal C > 2017 > 77 > 12 > 1-14

We derive the Shafieloo, Hazra, Sahni and Starobinsky (SHSS) phenomenological formula for the radioactive-like decay of metastable dark energy directly from the principles of quantum mechanics. To this aim we use the Fock–Krylov theory of quantum unstable states. We obtain deeper insight on the decay process as having three basic phases: the phase of radioactive decay, the next phase of damping oscillations,...

article

Economic growth cycles driven by investment delay

Adam Krawiec, Marek Szydłowski

Economic Modelling > 2017 > 67 > C > 175-183

We study the model of growth cycles in the framework of the Keynesian macroeconomic theory. The Kaldor–Kalecki growth model is the Kaldor business cycle model with two modifications: exponential growth introduced by Dana and Malgrange and Kaleckian investment time delay considered in this paper. This model has a form of a system of differential equations with time delay. The methods of dynamical system...

article

Emergence of running dark energy from polynomial f(R) theory in Palatini formalism

Marek Szydłowski, Aleksander Stachowski, Andrzej Borowiec

The European Physical Journal C > 2017 > 77 > 9 > 1-9

We consider FRW cosmology in $$f(R)= R+ \gamma R^2+\delta R^3$$ f ( R ) = R + γ R 2 + δ R 3 modified framework. The Palatini approach reduces its dynamics to the simple generalization of Friedmann equation. Thus we study the dynamics in two-dimensional phase space with some details. After reformulation of the model in the Einstein frame, it reduces to the FRW cosmological model with...

article

Starobinsky cosmological model in Palatini formalism

Aleksander Stachowski, Marek Szydłowski, Andrzej Borowiec

The European Physical Journal C > 2017 > 77 > 6 > 1-17

We classify singularities in FRW cosmologies, which dynamics can be reduced to the dynamical system of the Newtonian type. This classification is performed in terms of the geometry of a potential function if it has poles. At the sewn singularity, which is of a finite scale factor type, the singularity in the past meets the singularity in the future. We show that such singularities appear in the Starobinsky...

article

Cosmological implications of the transition from the false vacuum to the true vacuum state

Aleksander Stachowski, Marek Szydłowski, Krzysztof Urbanowski

The European Physical Journal C > 2017 > 77 > 6 > 1-13

We study cosmology with running dark energy. The energy density of dark energy is obtained from the quantum process of transition from the false vacuum state to the true vacuum state. We use the Breit–Wigner energy distribution function to model the quantum unstable systems and obtain the energy density of the dark energy parametrization $$\rho _\text {de}(t)$$ ρ de ( t ) . We also use...

article

Cosmological models with running cosmological term and decaying dark matter

Marek Szydłowski, Aleksander Stachowski

Physics of the Dark Universe > 2017 > 15 > C > 96-104

We investigate the dynamics of the generalized Λ CDM model, which the Λ term is running with the cosmological time. On the example of the model Λ ( t ) = Λ bare + α 2 t 2 we show the existence of a mechanism of the modification of the scaling law for energy density of dark matter: ρ dm ∝ a − 3 + λ ( t ) . We use an approach developed by Urbanowski in which...

article

Czy model Wszechświata powinien być strukturalnie stabilny

Paweł Tambor, Marek Szydłowski

Roczniki Filozoficzne > 2017 > 1 > 65-87

Pokazujemy, że kosmologia współczesna posiada cechy efektywnej teorii fizycznej podobnej do standardowego modelu cząstek elementarnych. Obecnie mamy do czynienia z konstytuowaniem się tzw. standardowego modelu kosmologicznego. W pracy wskazujemy na cechy charakterystyczne takiego modelu, który jest modelem kosmologicznym o maksymalnej symetrii (jednorodność i izotropowość przestrzenna) wypełnionego...

article

Dynamical system approach to running $$\Lambda $$ Λ cosmological models

Aleksander Stachowski, Marek Szydłowski

The European Physical Journal C > 2016 > 76 > 11 > 1-21

We study the dynamics of cosmological models with a time dependent cosmological term. We consider five classes of models; two with the non-covariant parametrization of the cosmological term $$\Lambda $$ Λ : $$\Lambda (H)$$ Λ ( H ) CDM cosmologies, $$\Lambda (a)$$ Λ ( a ) CDM cosmologies, and three with the covariant parametrization of $$\Lambda $$ Λ : $$\Lambda...

chapter

Brane Universes Tested by Supernovae

Włodzimierz Godłowski, Marek Szydłowski

Springer Proceedings in Physics > Cosmic Explosions > Supernovae, Gamma-Ray Bursters, and Cosmology > 579-584

Summary We discuss observational constrains coming from supernovae Ia imposed on the behavior of the Randall-Sundrum models. It is interesting that brane models predict brighter galaxies for such redshifts which is in agreement with the measurement of the z = 1.7 supernova. We also demonstrate that the fit to supernovae data can also be obtained, if we admit the “super-negative” dark energy p = −(4/3)...

article

Do sewn up singularities falsify the Palatini cosmology?

Marek Szydłowski, Aleksander Stachowski, Andrzej Borowiec, Aneta Wojnar

The European Physical Journal C > 2016 > 76 > 10 > 1-16

We investigate further (cf. Borowiec et al. JCAP 1601(01):040, 2016) the Starobinsky cosmological model $$R+\gamma R^2$$ R + γ R 2 in the Palatini formalism with a Chaplygin gas and baryonic matter as a source in the context of singularities. The dynamics reduces to the 2D sewn dynamical system of a Newtonian type (a piece-wise-smooth dynamical system). We demonstrate that the presence...

chapter

Toward testing the fundamental physics by SNIa data

Włodzimierz Godłowski, Marek Szydłowski, Wojciech Czaja

NATO Science Series II: Mathematics, Physics and Chemistry > The Gravitational Constant: Generalized Gravitational Theories and Experiments > 157-191

It is demonstrated how fundamental theory like M-theory can be tested by SNIa data. We discuss astronomical tests (redshift-magnitude relation, angular size minimum, age of the universe) for brane cosmologies with various types of matter sources on the brane. We also find the limits on exotic physics (brane models in Randall — Sundrum version) coming from CMB and BBN. We show that in the case...

chapter

Power Spectrum for the Distribution of Galaxies on the Sphere

Włodzimierz Godłowski, Magdalena Pietka, Jerzy Stelmach, Marek Szydłowski

ESO ASTROPHYSICS SYMPOSIA > Toward an International Virtual Observatory > 273-278

. A method of Gorski of calculation of the power spectrum for CMB for incomplete COBE data set is applied to the distribution of galaxies on the sphere. The power spectrum is found for the distribution of radiogalaxies in the Condon-Machalski sample [1] containing radiogalaxies with the flux greater than 2.5 J and the brightness less than 18 mag selected from the LCRS and NVSS catalogues. The calculated...

chapter

Power Spectrum for the Distribution of Galaxies on the Sphere

Włodzimierz Godłowski, Magdalena Pietka, Jerzy Stelmach, Marek Szydłowski

ESO ASTROPHYSICS SYMPOSIA > Toward an International Virtual Observatory > 273-278

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INFONA - science communication portal

Search results for: Marek Szydłowski

Czy fizyczne teorie efektywne są wiarygodną strategią osiągnięcia teorii finalnej?

Bifurcations in Ratra–Peebles quintessence models and their extensions

Metoda wyznaczania trajektorii w otoczeniu równowagi długookresowej w neoklasycznych modelach egzogenicznego wzrostu gospodarczego

Singularities in particle-like description of FRW cosmology

Simple cosmological model with inflation and late times acceleration

Swoistość ontologiczna i epistemologiczna kosmologii jako nauki o Wszechświecie

Swoistość ontologiczna i epistemologiczna kosmologii jako nauki o Wszechświecie

Quantum mechanical look at the radioactive-like decay of metastable dark energy

Economic growth cycles driven by investment delay

Emergence of running dark energy from polynomial f(R) theory in Palatini formalism

Starobinsky cosmological model in Palatini formalism

Cosmological implications of the transition from the false vacuum to the true vacuum state

Cosmological models with running cosmological term and decaying dark matter

Czy model Wszechświata powinien być strukturalnie stabilny

Dynamical system approach to running $$\Lambda $$ Λ cosmological models

Brane Universes Tested by Supernovae

Do sewn up singularities falsify the Palatini cosmology?

Toward testing the fundamental physics by SNIa data

Power Spectrum for the Distribution of Galaxies on the Sphere

Power Spectrum for the Distribution of Galaxies on the Sphere

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