This article aims at discussing the cosmological constant problem at a pedagogical but fully
technical level. We review how the vacuum energy can be regularized in flat and curved …

The arrival time is a simple classical concept, very common in laboratory practice. This
review describes theoretical problems encountered in trying to obtain a quantum …

The two-state vector formalism of quantum mechanics is a time-symmetrized approach to
standard quantum theory particularly helpful for the analysis of experiments performed on …

We have previously shown that three approaches to relational quantum dynamics—
relational Dirac observables, the Page-Wootters formalism and quantum deparametrizations …

According to the inflationary scenario for the very early Universe, all inhomogeneities in the
Universe are of genuine quantum origin. On the other hand, looking at these …

The concepts of time delay and dwell time in quantum mechanics, and their applications to
regular and chaotic scattering, to statistical mechanics, and to the tunneling time problem …

The progress of the factorization method since the 1935 work of Dirac is briefly reviewed.
Though linked with older mathematical theories the factorization seems an autonomous' …

Every clock is a physical system and thereby ultimately quantum. A naturally arising
question is thus how to describe time evolution relative to quantum clocks and, specifically …

A unified time analysis of photon and nonrelativistic particle tunnellings is presented, in
which time is regarded as a quantum observable, canonically conjugated to energy. Within …

We propose a time-of-arrival operator in quantum mechanics by conditioning on a quantum
clock. This allows us to bypass some of the problems of previous proposals, and to obtain a …