Zobrazeno 1 - 10
of 171
pro vyhledávání: '"Borowiec, Andrzej"'
In this paper, we find a class of Carrollian and Galilean contractions of (extended) BMS algebra in 3+1 and 2+1 dimensions. To this end, we investigate possible embeddings of 3D/4D Poincar\'{e} into the BMS${}_3$ and BMS${}_4$ algebras, respectively.
Externí odkaz:
http://arxiv.org/abs/2312.17245
Autor:
Borowiec, Andrzej, Postolak, Marcin
We found general solutions of matter stress-energy (non-)conservation in scalar-tensor FLRW-type cosmological models by extending the logotropic formalism to the case of non-minimal coupling between the scalar field and new dark fluid candidates. The
Externí odkaz:
http://arxiv.org/abs/2309.10364
Autor:
Borowiec, Andrzej
In this paper, we revise the concept of noncommutative vector fields introduced previously in Ref. [1,2], extending the framework, adding new results and clarifying the old ones. Using appropriate algebraic tools certain shortcomings in the previous
Externí odkaz:
http://arxiv.org/abs/2202.12102
Autor:
Borowiec, Andrzej, Kozak, Aleksander
We revisit a general minisuperspace (MSS) formalism for scalar-tensor (ST) FLRW type cosmological models in arbitrary frame with perfect fluid source. We discuss how to impose Cauchy data on the corresponding dynamical system in order to reconstruct
Externí odkaz:
http://arxiv.org/abs/2108.13324
We study noncommutative deformations of the wave equation in curved backgrounds and discuss the modification of the dispersion relations due to noncommutativity combined with curvature of spacetime. Our noncommutative differential geometry approach i
Externí odkaz:
http://arxiv.org/abs/2009.01051
Autor:
Borowiec, Andrzej, Kozak, Aleksander
Publikováno v:
JCAP07(2020)003
A class of scalar-tensor theories (STT) including a non-metricity that unifies metric, Palatini and hybrid metric-Palatini gravitational actions with non-minimal interaction is proposed and investigated from the point of view of their consistency wit
Externí odkaz:
http://arxiv.org/abs/2003.02741
Publikováno v:
SIGMA 15 (2019), 054, 22 pages
We propose a new generalisation of the Jordanian twist (building on the previous idea from [Meljanac S., Meljanac D., Pachol A., Pikutic D., J. Phys. A: Math. Theor. 50 (2017), 265201, 11 pages]). Obtained this way, the family of the Jordanian twists
Externí odkaz:
http://arxiv.org/abs/1812.05535
Autor:
Kozak, Aleksander, Borowiec, Andrzej
A new systematic approach extending the notion of frames to the Palatini scalar-tensor theories of gravity in various dimensions n>2 is proposed. We impose frame transformation induced by the group action which includes almost-geodesic and conformal
Externí odkaz:
http://arxiv.org/abs/1808.05598
Publikováno v:
Galaxies 2018, 6(3), 70
A new simple expression for the circular velocity of spiral galaxies is proposed and tested against HI Nearby Galaxy Survey (THINGS) data set. Its accuracy is compared with the one coming from MOND.
Comment: 9 pages, 3 figures, 2 tables; this ar
Comment: 9 pages, 3 figures, 2 tables; this ar
Externí odkaz:
http://arxiv.org/abs/1804.09620
Publikováno v:
Eur. Phys. J. C77, 603 (2017)
We consider FRW cosmology in $f(R)= R+ \gamma R^2+\delta R^3$ 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 detai
Externí odkaz:
http://arxiv.org/abs/1707.01948