The 4th Conference of the Polish Society on Relativity

Session

Plenary Session 4

26 Sept 2017, 11:00

Kazimierz Dolny, Poland

44. Axial gravitational waves in FLRW cosmology and memory effect

Edward Malec

26/09/2017, 11:00

Oral presentation (preferred)

We show exemplary initial metrics for gravitational axial waves, that are twice differentiable but which are not $C^2$. They generate wave pulses that interact with matter in the radiation cosmological era. This forces the radiation matter to rotate. This rotation is permanent - it persists after the passage of the gravitational pulse. In contrast to that, we explicitly show that a class...

45. Gravitational waves in Friedman-Lemaitre-Robertson-Walker cosmology, material perturbations and the Huygens principle

Wojciech Kulczycki

26/09/2017, 11:20

Oral presentation (preferred)

We analyze propagation equations for the polar modes of gravitational waves in cosmological space-times. We prove that polar gravitational waves must perturb the density and non-azimuthal components of the velocity of material medium of the Friedman-Lemaitre-Robertson-Walker space-times. Axial gravitational waves can in􏰎uence only the azimuthal velocity. The whole gravitational dynamics...

62. Properties of null one-way solution of Maxwell equations with separated variables in Kerr space-time

Yurii Taistra (Pidstrygach Institute for Applied Problems for Mechanics and Mathematics, NAS of Ukraine), Volodymyr Pelykh (Pidstrygach Institute for Applied Problems for Mechanics and Mathematics, NAS of Ukraine)

26/09/2017, 11:40

Oral presentation (preferred)

We are finding in class of null one-way fields solution with separated variables of Maxwell equations in Kerr space-time. Obtained solution describes left and right circularly-polarized waves. From this solution we deduce the dependence of polarization rotation angle from frequency as well as expression for phase shift.

26. Gravitational entropy and the cosmological “no-hair” conjecture

Krzysztof Bolejko (The University of Sydney)

26/09/2017, 12:00

Oral presentation (preferred)

Gravitational entropy and the cosmological “no-hair” conjecture

Gravitational entropy [1] and the “no-hair” conjectures [2, 3] are seemingly contradictory: the growth of the first one is associated with the growth of inhomogeneity [4, 5, 6], while the second one argues that the dark energy dominated Universe will asymptotically approach a homogeneous and isotropic de Sitter state[7, 8].
In...

69. TT tensors in flat spaces of any dimension

Jacek Tafel (University of Warsaw)

26/09/2017, 12:20

Oral presentation (preferred)

Traceless tensors with vanishing divergence (TT tensors) play a big role in the initial value problem in general relativity. They are solutions of the momentum constraints which can be extended to solutions of the full system of constraints by means of the conformal method of Lichnerowicz. First, we describe all divergence-free tensors T in flat spaces in terms of potentials which form a four...

97. Towards a theory of nonlinear gravitational waves: a systematic approach to nonlinear gravitational perturbations in vacuum

Andrzej Rostworowski

26/09/2017, 12:40

Oral presentation (preferred)

I will present a systematic and robust approach to nonlinear gravitational perturbations of vacuum spacetimes. In particular, I will show that the system of perturbative Einstein equations reduces at each perturbation order to two (for each gravitational mode in $3+1$ dimensions on which our study is focused) scalar wave equations, and then we show how the metric perturbations can be...