A quantum system is like an island gradually eroded by the ocean. The waves, representing environmental influence, wash away the shores, stripping the island of its unique contours. The GKLS equation (Gorini–Kossakowski–Lindblad–Sudarshan) describes exactly how quickly this 'quantumness' fades.
But every wave has an energy source. The authors dug deeper and asked: what if the ocean's energy cannot drop below a certain level? It turns out that erosion then proceeds differently than the equation predicts. The probability that the island still retains its quantum features decays more slowly — not as a straight line at the start, but as a smooth curve.
This means that an exact, eternal description of irreversibility would demand infinite initial energy or a violation of fundamental laws. The GKLS equation remains an excellent working tool, but now we know that behind its elegant formulas lies an idealization. The ocean is not bottomless, and the island disappears in a slightly trickier way than we thought.
The term 'semigroup' in the equation's name means the process moves only forward in time, like sand that cannot be gathered back into the top of an hourglass.
In the novel 'The End of Eternity,' Isaac Asimov describes irreversible changes to reality, but even there, energy obeys laws, not an equation without a floor.