The exploration of the universe has recently entered a new era thanks to the multi-
messenger paradigm, characterized by a continuous increase in the quantity and quality of …

Abstract The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders
about the fundamental theory of nature at play in the extreme gravity regime, where the …

Very compact objects probe extreme gravitational fields and may be the key to understand
outstanding puzzles in fundamental physics. These include the nature of dark matter, the …

Perturbations of black holes, initially considered in the context of possible observations of
astrophysical effects, have been studied for the past 10 years in string theory, brane-world …

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

Quantum gravity poses the problem of merging quantum mechanics and general relativity,
the two great conceptual revolutions in the physics of the twentieth century. The loop and …

The problem of describing the quantum behavior of gravity, and thus understanding
quantum spacetime, is still open. Loop quantum gravity is a well-developed approach to this …

A new functional calculus, developed recently for a fully non-perturbative treatment of
quantum gravity, is used to begin a systematic construction of a quantum theory of geometry …

Bringing together the key ideas from nonequilibrium statistical mechanics and powerful
methodology from quantum field theory, this 2008 book captures the essence of …

During the last twenty-five years evidence has been mounting that a black-hole surface area
has a discrete spectrum. Moreover, it is widely believed that area eigenvalues are uniformly …