Madrid, 26 (European Press)
A team of physicists has shown how quantum systems can evolve simultaneously along two opposite arrows, both forward and backward in time.
The study, published in the latest issue of Communication Physics, makes it necessary to rethink how we understand and represent the flow of time in contexts in which quantum laws play a critical role, according to the authors.
For centuries, philosophers and physicists have thought about the existence of time. However, in the classical world, our experience seems to eliminate any doubt that time exists and goes on. Indeed, in nature, processes tend to evolve spontaneously from less disordered states to more disordered states, and this tendency can be used to determine the arrow of time. In physics, this is described by the term “entropy,” which is the physical quantity that determines the degree of disorder in a system.
Dr Julia Rubino of the University of Bristol’s Quantum Engineering Technology Laboratories (QET labs) and lead author of the publication said in a statement:
“If a phenomenon produces a large amount of entropy, then observing its reversal over time is so unlikely that it becomes intrinsically impossible. However, when the entropy produced is small enough, there is a not insignificant possibility that a time reversal of the phenomenon will of course occur.”
“We can take the sequence of things we do in our morning routine as an example. If they showed us that our toothpaste was moving from the toothbrush to its tube, we would have no doubt that it was a re-recording of our day. However, if we squeeze the tube gently so that only a small portion of the tube comes out. toothpaste, and it wouldn’t be out of the question to see it go back into the tube, sucked up by the tube’s pressure.”
The authors of the study, led by Professor Caslav Bruckner of the University of Vienna and IQOQI-Vienna, applied this idea to the quantum world, for which the principle of quantum superposition is one of its properties, according to which it is possible that this system is in both states at the same time.
“Extending this principle to the arrows of time, it turns out that quantum systems that evolve in one direction or another over time (toothpaste in or out of the tube) can also find themselves evolving simultaneously along both time directions.
“Although this idea seems completely absurd when applied to our everyday experience, the laws of the universe are, at their most basic level, based on the principles of quantum mechanics. This raises the question why these superpositions of the flow of time do not exist in nature,” said Dr. Rubino.
Dr. Gonzalo Manzano, co-author of the University of the Balearic Islands, said: “In our work, we determine the entropy produced by an evolving system in the quantum superposition of processes with opposite time arrows. We find that this often results in projecting the system in a well-defined time direction, which corresponds to the process most A possibility of both, however, when there are small amounts of entropy (for example, when so little toothpaste is spilled that it can be seen to be sucked into the tube), then you can physically observe the consequences of the system that developed back-and-forth temporal directions at the same time physically.”
Aside from the fundamental property that time itself may not be well defined, the work also has practical implications in quantum thermodynamics. Placing a quantum system in an alternative time arrow overlay can provide performance advantages for heat engines and refrigerators.
Dr. Rubino said: “Although time is often treated as an ever-increasing parameter, our study shows that the laws that govern its flow in quantum mechanics contexts are more complex. This may indicate that we need to rethink the way we represent this Quantum in all those contexts where quantum laws play a crucial role.”
