Why does time only flow forward? A physicist's search for answers

Starting from the puzzle of time's arrow — why natural processes evolve asymmetrically toward the future — this doctoral work branches into three connected areas: identifying in-principle observable signatures of quantum theories, explaining how systems approach thermodynamic equilibrium from first principles, and constructing a self-consistent model of semiclassical gravity using relativistic collapse theories. The ambition is to close the gap between quantum foundations and things we might actually measure.