Zobrazeno 1 - 10
of 161
pro vyhledávání: '"Babichev, Eugeny"'
Autor:
Babichev, Eugeny, Charmousis, Christos, Muntz, Benjamin, Padilla, Antonio, Saltas, Ippocratis D.
We revisit multi-messenger constraints from neutron star mergers on the speed of propagation of gravitational and electromagnetic waves in Horndeski and beyond Horndeski theories. By considering non-trivial couplings between the dark energy field and
Externí odkaz:
http://arxiv.org/abs/2407.20339
We study a subclass of Horndeski gravity which has both global conformal and shift symmetries. Global symmetries are characterised by the presence of a conserved current which has been shown to be of particular importance for the integrability featur
Externí odkaz:
http://arxiv.org/abs/2407.11157
We study new classes of metric transformations in the context of scalar-tensor theories, which involve both higher derivatives of the scalar field and derivatives of the metric itself. In general, such transformations are not invertible as they invol
Externí odkaz:
http://arxiv.org/abs/2405.13126
Autor:
Babichev, Eugeny, Charmousis, Christos, Doneva, Daniela D., Gyulchev, Galin N., Yazadjiev, Stoytcho S.
There is strong observational evidence that almost every large galaxy has a supermassive black hole at its center. It is of fundamental importance to know whether such black holes are described by the standard Kerr solution in General Relativity (GR)
Externí odkaz:
http://arxiv.org/abs/2403.16192
Static black holes in general relativity modified by a linear scalar coupling to the Gauss-Bonnet invariant always carry hair. We show that the same mechanism that creates the hair makes it incompatible with a cosmological horizon. Other scalar-tenso
Externí odkaz:
http://arxiv.org/abs/2403.15537
In this chapter, we discuss explicit black hole solutions in higher-order scalar-tensor theories. After a brief recap of no-hair theorems, we start our discussion by so-called stealth solutions present in theories with parity and shift symmetry. Stea
Externí odkaz:
http://arxiv.org/abs/2309.12229
We present solutions of DHOST theories describing a rotating black hole embedded in an expanding universe. The solution is constructed by conformal transformation of a stealth Kerr(-de Sitter) black hole. The conformal factor depends explicitly on th
Externí odkaz:
http://arxiv.org/abs/2305.17129
Starting from a generalised Kaluza-Klein action including arbitrary Horndeski potentials, we establish integrability and compatibility conditions that solve the generic field equations for spherical symmetry. The resulting theories can be identified
Externí odkaz:
http://arxiv.org/abs/2303.04126
In arbitrary higher dimension, we consider the combination of Lovelock gravity alongside a scalar-tensor action built out of higher order operators and Euler densities. The latter action is constructed in such a way as to ensure conformal invariance
Externí odkaz:
http://arxiv.org/abs/2302.02920
We study black holes in a modified gravity scenario involving a scalar field quadratically coupled to the Gauss-Bonnet invariant. The scalar is assumed to be in a spontaneously broken phase at spatial infinity due to a bare Higgs-like potential. For
Externí odkaz:
http://arxiv.org/abs/2207.03944