3 papers
gr-qc2025
Coupling constant metamorphosis, Fermat principle and light propagation in Kerr metric
Joanna Piwnik, Joanna Gonera, Cezary Gonera +1
The geodesics of Kerr's metric are described by the four-dimensional Hamiltonian dynamics integrable in the Arnold--Liouville sense. It can be reduced to two-dimensional one by the…
gr-qc2025
Fermat Principle and weak deflection angle from Lindstedt-Poincare method
Joanna Piwnik, Joanna Gonera, Piotr Kosinski
The Fermat principle is advocated to be a convenient tool to analyze the light propagation in a curved space time. It is shown that in the weak deflection regime the light ray traj…
gr-qc2024
Fermat's Principle in General Relativity via Herglotz Variational Formalism
Joanna Piwnik, Joanna Gonera, Piotr KosiÅski
New form of Fermat's principle for light propagation in arbitrary (i.e. in general neither static nor stationary) gravitational field is proposed. It is based on Herglotz extension…