Michal Kamionka

University of Wroclaw | WROC · Faculty of Physics and Astronomy

Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting \(\Lambda \) CDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its si...

We investigate observational constraints on Brans-Dicke cosmological model using observational data coming form distant supernovae type Ia, the Hubble function $H(z)$ measurements, information coming from Alcock-Paczy{\'n}ski test and baryon acoustic oscillations (BAO). Our analysis is based on modified Friedmann function resulting form dynamical i...

We show that future singularities which have appeared in the Palatini cosmological models investigated in [1] are of finite size at finite time type [2].

New constraints on previously investigated Palatini cosmological models [arXiv:1109.3420] have been obtained by adding Gamma Ray Burst data [arXiv:1205.2954].

We study new FRW type cosmological models of modified gravity treated on the background of Palatini approach. These models are generalization of Einstein gravity by the presence of a scalar field non-minimally coupled to the curvature. The models employ Starobinsky's term in the Lagrangian and dust matter. Therefore, as a by-product, an exhausted c...

In this paper we study possible observational consequences of the bouncing cosmology. We consider a model where a phase of inflation is preceded by a cosmic bounce. While we consider in this paper only that the bounce is due to loop quantum gravity, most of the results presented here can be applied for different bouncing cosmologies. We concentrate...

In this paper we investigate power spectrum of a smoothed scalar field. The smoothing leads to the regularisation of the UV divergences and can be related with the internal structure of the considered field or the space itself. We apply procedure of smoothing to the quantum fluctuations generated during the phase of cosmic inflation. We study wheth...