This is just an illusion created by quantum entanglement.

The nature of time has always eluded scientists, who have spent centuries trying in vain to unravel its mysteries. Is time something “external” to us or is it just a “trick” by which our brains organize reality? And if it turns out to be external, then is time something continuous, a smooth, endless and constant flow, or, conversely, is it “discrete”, that is, divided, like matter, into small independent “particles of time”, such as frames from a film ?

“If no one asks me,” St. Augustine said very correctly, “I know what time is. But if I had to explain this to someone, I wouldn’t know how to do it.

Now a team from Italy’s National Research Council has created a new theoretical model in which time belongs entirely to the strange world of quantum mechanics, where the laws of physics no longer apply and our “logic” seems like the madness of the past. In particular, say the researchers in a paper just published in Physical Review A, time may not be a fundamental element of our physical reality and may exist only as a consequence of the well-known (but not yet fully understood) phenomenon of “quantum entanglement”, in which two objects are so inextricably linked that any change we make to one instantly affects the other, no matter how far away it is.

“Over the centuries,” says Alessandro Coppo, lead author of the study, “time has entered physics as an essential ingredient that should not be questioned. It is so deeply ingrained in our understanding of reality that until relatively recently people believed that there was no need to define time. But this idea began to change with the advent of the 20th century, when the theories of quantum physics and general and special relativity began to offer conflicting views on the nature of time.

“Classical” or quantum reality?

For example, in Einstein’s general theory of relativity, time is part of the very structure of the Universe. Our physical reality is essentially located in space-time. According to this theory, time, like space, can be deformed and expanded under the influence of gravity. However, just the opposite, quantum mechanics views time as something inflexible and does not change in the same way as other properties of a quantum object. Therefore, in order to record its passage, it is absolutely necessary for an observer external to the object to consult a clock.

It is true that general relativity and quantum theory describe objects on very different scales: some stars, others atoms, but because all objects, from the largest to the smallest, exist in the same universe, many physicists believe that The concept of time must be something holistic, universal, regardless of the scale we are considering. And that’s exactly what Coppo and his colleagues tried to do with their model.

To achieve this, they turned to a strange but promising idea that originated in the 1980s and put it through several mathematical tests. Essentially, the idea is that when we see an object change over time, we check to see if time is actually passing, just because that object is “entangled” with a clock. This means that a truly external observer outside the entangled system would see a completely static and unchanging Universe. Within this framework, time would not be part of reality, it would not be an accomplished and inevitable fact, but simply a consequence of the intertwining itself.

In their mathematical model, the researchers imagined the clock as a system of small theoretical magnets intertwined with a quantum oscillator, a quantum version of a spring. Coppo and his team chose these objects as models because they are well understood mathematically, allowing the development of a clear theoretical test case, ideal for later setting the stage for possible subsequent experimental tests.

Thus, they discovered that their system could be described by a version of the famous Schrödinger equation, which is used to predict the behavior of quantum particles, but with a significant difference. Although Schrödinger’s equation contains a variable we call time, the new equation replaces it with a variable that enumerates the quantum states of magnets.

The researchers then repeated the same calculation, but assumed that the magnets and oscillator were large enough that quantum effects would not change their behavior. The basic idea was that time can be a consequence of entanglement even for objects that appear more classical than quantum. And it turned out that they were right. Their equations actually matched those that physicists had used to predict the behavior of classical objects as simple as the rolling of bowling balls since the 19th century. But even so, the variable that marked each stage of the oscillator’s behavior was a byproduct of quantum entanglement.

Time arises from quanta

In other words, Coppo and his colleagues have combined quantum and classical time, and the result implies that perhaps the only way to think about time is as if it emerged from quanta. Of course, this is precisely Coppo and his colleagues’ idea: entanglement exists only in quantum theory, and their new model suggests that the existence of time arises from there. “We believe,” Coppo emphasizes, “that nature is truly quantum.”

If this were indeed the case, it could mean that our perception of the passage of time is due to some kind of entanglement in the physical world around us. And that an observer, stranded in a Universe free of entanglements (as some theories suggest ours was in its infancy), will not see any changes. Everything remains static.

Now the most important question is to find a way to test these ideas. Some researchers have already responded by saying that the possibility of time arising from quantum entanglement is promising, but more details may need to be added before we can fully understand what time is and begin to explore it experimentally.