Strong Gravity

Horava's proposal to use Lifshitz propagators for gravitons above certain energy scales may provide a viable theory of quantum gravity without further need of UV completion. In my talk, I will address the question of whether the complete lack of Lorentz invariance above a certain energy scale is a big problem for any realistic construction. I will argue that it is not, provided that the onset of Lifshitz scaling for gravitons occurs at momentum scale much lower than the Planck mass.

The equation of state of matter at and above nuclear densities remains a major theoretically uncertain prediction of QCD. Observations of the mass-radius relationship of neutron stars constrain, and can directly measure, the dense matter equation of state. I will discuss how measurements of neutron star radii have already constrained the dEOS, and how future work will directly measure the dEOS, providing an important constraint on models of the strong force.

There exist evidences that magnetic field in
the vicinity of astrophysical black holes plays an important role. In
particular it is required for explanation of such phenomenon as jet formation.
Study of such problems in all their complexity requires 3D numerical
simulations of the magnetohydrodynamics in a strong gravitational field. Quite
often when dealing with such a complicated problem it is instructive to
consider first its simplifications, which can be treated either analytically,

In many theories with fundamental preferred frame, such as Einstein-Aether or Gravitational Aether theories, K-essence, Cuscuton theory, Shape Dynamics, or (non-projectable) Horava-Lifshitz gravity, the low energy theory contains a fluid with superluminal or incompressible excitations. In this talk, I study the formation of black holes in the presence of such a fluid. In particular, I focus on the incompressible limit of the fluid (or Constant Mean Curvature foliation) in the space-time of a spherically collapsing shell within an asymptotically cosmological space-time.