Quasinormal modes are eigenmodes of dissipative systems. Perturbations of classical
gravitational backgrounds involving black holes or branes naturally lead to quasinormal …

Analogue gravity is a research programme which investigates analogues of general
relativistic gravitational fields within other physical systems, typically but not exclusively …

In most cosmological models, rapid expansion of space marks the first moments of the
Universe and leads to the amplification of quantum fluctuations. The description of …

Beyond Einstein's Gravity is a graduate level introduction to extended theories of gravity and
cosmology, including variational principles, the weak-field limit, gravitational waves …

Motivated by ideas about quantum gravity, a tremendous amount of effort over the past
decade has gone into testing Lorentz invariance in various regimes. This review …

In electrical engineering metamaterials have been developed that offer unprecedented
control over electromagnetic fields. Here, we show that general relativity provides the …

The theory of gravitational lensing is reviewed from a spacetime perspective, without quasi-
Newtonian approximations. More precisely, the review covers all aspects of gravitational …

We discuss effects of loss of coherence in low energy quantum systems caused by or related
to gravitation, referred to as gravitational decoherence. These effects, resulting from random …

Event horizons of astrophysical black holes and gravitational analogues have been
predicted to excite the quantum vacuum and give rise to the emission of quanta, known as …

The k-essence theories admit in general the superluminal propagation of the perturbations
on classical backgrounds. We show that in spite of the superluminal propagation the causal …