48 citations · 179 across the 14 of their papers we have counts for
14 papers
Bimetric interactions based on metric congruences
Mikica Kocic
In massive gravity and bigravity, spin-2 interactions are defined in terms of a square root matrix that involves two metrics. In this work, the interactions are constructed using a…
Generalized Vaidya solutions in bimetric gravity
Marcus Högås, Mikica Kocic, Francesco Torsello +1
In general relativity, the endpoint of spherically symmetric gravitational collapse is a Schwarzschild--[(A)dS] black hole. In bimetric gravity, it has been speculated that a stati…
Note on bimetric causal diagrams
Mikica Kocic
A new kind of diagrams is presented, showing the causal structure of bimetric interactions.
Spherical dust collapse in bimetric relativity: Bimetric polytropes
Mikica Kocic, Francesco Torsello, Marcus Högås +1
We present a method for solving the constraint equations in the Hassan-Rosen bimetric theory to determine the initial data for the gravitational collapse of spherically symmetric d…
Covariant BSSN formulation in bimetric relativity
Francesco Torsello, Mikica Kocic, Marcus Högås +1
Numerical integration of the field equations in bimetric relativity is necessary to obtain solutions describing realistic systems. Thus, it is crucial to recast the equations as a…
On the ratio of lapses in bimetric relativity
Mikica Kocic, Anders Lundkvist, Francesco Torsello
The two lapse functions in the Hassan-Rosen bimetric theory are not independent. Without knowing the relation between them, one cannot evolve the equations in the 3+1 formalism. Th…
Causal propagation of constraints in bimetric relativity in standard 3+1 form
Mikica Kocic
The goal of this work was to investigate the propagation of the constraints in the ghost-free bimetric theory where the evolution equations are in standard 3+1 form. It is establis…
Geometric mean of bimetric spacetimes
Mikica Kocic
We use the geometric mean to parametrize metrics in the Hassan-Rosen ghost-free bimetric theory and pose the initial-value problem. The geometric mean of two positive definite symm…
Spacetime symmetries and topology in bimetric relativity
Francesco Torsello, Mikica Kocic, Marcus Högås +1
We explore spacetime symmetries and topologies of the two metric sectors in Hassan-Rosen bimetric theory. We show that, in vacuum, the two sectors can either share or have separate…
On Birkhoff's theorem in ghost-free bimetric theory
Mikica Kocic, Marcus Högås, Francesco Torsello +1
We consider the Hassan-Rosen bimetric field equations in vacuum when the two metrics share a single common null direction in a spherically symmetric configuration. By solving these…
Algebraic Properties of Einstein Solutions in Ghost-Free Bimetric Theory
Mikica Kocic, Marcus Högås, Francesco Torsello +1
A known fact is that an Einstein solution in one sector in ghost-free bimetric theory implies an Einstein solution in the other sector. Earlier studies have also shown that some cl…
On the local structure of spacetime in ghost-free bimetric theory and massive gravity
S. F. Hassan, Mikica Kocic
The ghost-free bimetric theory describes interactions of gravity with another spin-2 field in terms of two Lorentzian metrics. However, if the two metrics do not admit compatible n…
Classification and asymptotic structure of black holes in bimetric theory
Francesco Torsello, Mikica Kocic, Edvard Mortsell
We study general properties of static and spherically symmetric bidiagonal black holes in Hassan-Rosen bimetric theory. In particular, we explore the behaviour of the black hole so…
Absence of ghost in a new bimetric-matter coupling
S. F. Hassan, Mikica Kocic, Angnis Schmidt-May
Interactions in bimetric theory, which can describe gravity in the presence of an extra spin-2 field, are severely constrained by the requirement of the absence of the Boulware-Des…