For the first time, a physicist has experimentally watched time emerge from within an isolated quantum system by creating a "mini-universe."
In a study published in Physical Review Research, Giovanni Barontini of the University of Birmingham used a cloud of ultracold atoms. The system was so well isolated it had nothing external to use as a clock.
Barontini split the system in two and ignored one half-the "dark sector"-to demonstrate that time could arise entirely from within the system itself.