Glauber oscillator and time travel

The standard quantum mechanics does not forbid time-travel. However, some alternative formulations (based on the so called "rigged Hilbert space") include irreversibility as a fundamental principle: a quantum particle that decays cannot travel back in time.

There are not direct evidences of the irreversibility of decay processes, but the new quantum mechanics predicts that the decay rates are quantized.

If one observes the quantization of the decay rates, one can claim to have provided experimental support to the irreversible formulation of quantum mechanics.

In simple terms, one can claim that time-travel is not possible at the quantum level (...and also at the classical level).

Silvia Gentilini, Maria Chiara Braidotti, Giulia Marcucci, Eugenio Del Re, and Claudio Conti simulated in the laboratory one of the simplest models of the irreversible quantum mechanics, that follows an original proposal of Glauber. A laser beam emulates a quantum particle in a reversed harmonic oscillator, as a result the first experimental evidence of the quantization of decay time is reported in a paper published in Scientific Reports.