Dynamics of massive gravity
File(s)
Author(s)
Kozuszek, Jan
Type
Thesis
Abstract
First formulated in 2010, the de Rham-Gabadadze-Tolley (dRGT) theory of massive gravity is the
unique healthy theory of a massive spin-2 particle. Despite considerable interest of the field since
the publication of this model, relatively little remained known about its non-linear dynamics until
the last few years. Here we review this recent progress and present several new findings. We give
a dynamical formulation of the equations of motion, by performing a 3 + 1 split and identifying a
choice of momenta which allows for a simplification of the constraints present in the theory. We
also provide a harmonic reformulation of these equations for the minimal model and perform a
formal analysis thereof, finding evidence that it may be strongly hyperbolic in a neighbourhood of
Minkowski space. We then move on to a numerical study of spherically symmetric gravitational
collapse, taking a massless scalar field as our matter content. It turns out that this appears to lead
to singularities, which we argue cannot be removed by a gauge transformation, and which are not
screened from an observer at asymptotic infinity. However, if we also endow the remaining gravi-
ton degree of freedom with a sufficiently large initial amplitude, the behaviour instead changes
to resemble that of a horizon forming in standard GR. This represents the first evidence of viable
black hole candidates in this context.
unique healthy theory of a massive spin-2 particle. Despite considerable interest of the field since
the publication of this model, relatively little remained known about its non-linear dynamics until
the last few years. Here we review this recent progress and present several new findings. We give
a dynamical formulation of the equations of motion, by performing a 3 + 1 split and identifying a
choice of momenta which allows for a simplification of the constraints present in the theory. We
also provide a harmonic reformulation of these equations for the minimal model and perform a
formal analysis thereof, finding evidence that it may be strongly hyperbolic in a neighbourhood of
Minkowski space. We then move on to a numerical study of spherically symmetric gravitational
collapse, taking a massless scalar field as our matter content. It turns out that this appears to lead
to singularities, which we argue cannot be removed by a gauge transformation, and which are not
screened from an observer at asymptotic infinity. However, if we also endow the remaining gravi-
ton degree of freedom with a sufficiently large initial amplitude, the behaviour instead changes
to resemble that of a horizon forming in standard GR. This represents the first evidence of viable
black hole candidates in this context.
Version
Open Access
Date Issued
2025-07-31
Date Awarded
01/11/2025
Advisor
Wiseman, Toby
Sponsor
Science and Technology Facilities Council (Great Britain)
Publisher Department
Department of Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)