Universita degli Studi di Pavia Italy

## Talks by Lorenzo Maccone

## Quantum measurements of time

Lorenzo Maccone
Universita degli Studi di Pavia Italy

"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 Hermitian time of arrival operator whose probability distribution arises from the Born rule and which has a clear physical interpretation. The same procedure can be employed to measure the ""time at which some event happens"" for arbitrary events (and not just specifically for the arrival time of a particle).
This talk is based on the paper: L. Maccone, K. Sacha, Quantum measurements of time, Phys. Rev. Lett.

## Quantum mechanics and the arrow of time

Lorenzo Maccone
Universita degli Studi di Pavia Italy

The arrow of time dilemma: the laws of physics are invariant for time inversion, whereas the familiar phenomena we see everyday are not (i.e. entropy increases). I show that, within a quantum mechanical framework, all phenomena which leave a trail of information behind (and hence can be studied by physics) are those where entropy necessarily increases or remains constant. All phenomena where the entropy decreases must not leave any information of their having happened. This situation is completely indistinguishable from their not having happened at all.