A little digging turns up this, which discusses their experimental work: https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.128.080401 https://journals.aps.o

A little digging turns up this, which discusses their experimental work: https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.128.080401 https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.128.080... "(2022) Emergence of Constructor-Based Irreversibility in Quantum Systems: Theory and Experiment, Marletto & Vedral" That's related to this quote from the article: > "But crucially, the theory also predicts that the row becomes even less able to do the reverse transformation from B2 to B1. The researchers have confirmed this prediction experimentally using photons for B and a fiber optic circuit to simulate a row of three qubits." The experiment is rather complex, and would take a long time to analyze and understand in depth. They appear to be claiming that microscopic reversibility, a cornerstone of atomic-molecular kinetic theory, is being violated in their setup? Seems like a rather extraordinary claim but it passed peer review in a major journal so, worth digging into probably. For those who want an introductory overview of the issue, this is a good one: https://www.thoughtco.com/laws-of-thermodynamics-p3-2699420 https://www.thoughtco.com/laws-of-thermodynamics-p3-2699420 > "Kinetic Theory & the Laws of Thermodynamics The laws of thermodynamics do not particularly concern themselves with the specific how and why of heat transfer, which makes sense for laws that were formulated before the atomic theory was fully adopted. They deal with the sum total of energy and heat transitions within a system and do not take into account the specific nature of heat transference on the atomic or molecular level." In practice the second law is not all that useful although it's philosophically important I suppose. For example, a redwood tree growing from a redwood seed plus simple inputs (CO2, H2O, photons, NH3 etc.) is clearly a local decrease in entropy, as opposed to the dispersal of those elements when a redwood tree burns or falls and is digested by fungi, but since solar fusion is creating a much greater increase in entropy, there are no second law violations. Similarly the creation of heavy elements in a supernova would seem to be a decrease in entropy but the release of all that energy to the surrounding universe ensures no second law violations take place. In practice it's very difficult to do all the accounting for even moderately complex systems.