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 …

Singularities in any physical theory are either remarkable indicators of the unknown
underlying fundamental theory, or indicate a change in the description of the physical reality …

The goal of this review is to present an introduction to loop quantum gravity—a background-
independent, non-perturbative approach to the problem of unification of general relativity …

Loop quantum cosmology (LQC) is the result of applying principles of loop quantum gravity
(LQG) to cosmological settings. The distinguishing feature of LQC is the prominent role …

Recently, two types of static black hole models that retain general covariance have been
proposed within the Hamiltonian constraint approach to effective quantum gravity (EQG). We …

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 …

An improved Hamiltonian constraint operator is introduced in loop quantum cosmology.
Quantum dynamics of the spatially flat, isotropic model with a massless scalar field is then …

We review the question of whether the fundamental laws of nature limit our ability to probe
arbitrarily short distances. First, we examine what insights can be gained from thought …

I review the current status of phenomenological programs inspired by quantum-spacetime
research. I stress in particular the significance of results establishing that certain data …

Quantum gravity is expected to be necessary in order to understand situations in which
classical general relativity breaks down. In particular in cosmology one has to deal with …