28 citations · 46 across the 11 of their papers we have counts for
11 papers
Quasi-topological gravity for 4-dimensional Taub-NUT, near-horizon extreme Kerr, and swirling symmetries
Aimeric Colléaux, Ivan Kolář, Tomáš Málek
We classify 4-dimensional gravitational theories with integrability properties analogous to quasi-topological gravity, but for metrics with the symmetries of spherical, hyperbolic,…
Static spherically symmetric Kundt vacuum solutions of higher-derivative gravities
Breno L. Giacchini, Ivan Kolář, Vojtěch Pravda +1
We study static spherically symmetric Kundt solutions to the vacuum field equations of quadratic gravity with a cosmological constant, as well as specific models of six-derivative…
Canonical quantization of all minisuperspaces with consistent symmetry reductions
Poula Tadros, Ivan Kolář, Otakar Svítek
We present the quantization of all symmetry reductions of the Einstein--Hilbert Lagrangian that correctly reproduce the reduced Einstein's field equations -- i.e., characterized by…
Double Wick rotations between symmetries of Taub-NUT, near-horizon extreme Kerr, and swirling spacetimes
Aimeric Colléaux, Ivan Kolář, Tomáš Málek
We explicitly show that certain 4-dimensional infinitesimal group actions with 3-dimensional orbits are related by double Wick rotations. In particular, starting with the symmetrie…
Neglected solutions in quadratic gravity
Breno L. Giacchini, Ivan Kolář
We report on several previously overlooked families of static spherically symmetric solutions in quadratic gravity. Our main result concerns the existence of solutions whose leadin…
Rotating Carroll Black Holes: A No Go Theorem
Ivan Kolář, David Kubiznak, Poula Tadros
Recently, there has been a lot of interest in Carroll black holes and in particular whether or not one could find a Carrollian analogue of a rotating black hole spacetime. Here we…
Black holes and other exact solutions in six-derivative gravity
Breno L. Giacchini, Ivan Kolář
We study exact static spherically symmetric vacuum solutions in generic six-derivative gravity (i.e., without assuming specific relations between the coupling constants). Using mod…
Intrinsically-defined higher-derivative Carrollian scalar field theories without Ostrogradsky instability
Poula Tadros, Ivan Kolář
We derive the most generic Carrollian higher derivative free scalar field theory intrinsically on a Carrollian manifold. The solutions to these theories are massless free particles…
Non-local scalar fields in static spacetimes via heat kernels
Ivan Kolář
We solve the non-local equation for i) static scalar fields in static spacetimes and ii) time-dependent scalar fields in ultrastatic spacetimes. C…
On the geometry of variational calculus on some functional bundles
Antonella Cabras, Josef Janyška, Ivan Kolář
We first generalize the operation of formal exterior differential in the case of finite dimensional fibered manifolds and then we extend it to certain bundles of smooth maps. In or…
Functorial prolongations of some functional bundles
Antonella Cabras, Josef Janyška, Ivan Kolář
We discuss two kinds of functorial prolongations of the functional bundle of all smooth maps between the fibers over the same base point of two fibered manifolds over the same base…