A groundbreaking study was recently published by an international team of scientists. In it, they showed that quantum computers are not limited to the classical understanding of time.
Scientists decided to investigate whether it is possible to use quantum computers to overcome one of the biggest problems: causal asymmetry. When you observe the course of events, your brain begins to predict what will happen next. This way, when you watch a video that unfolds an action scene, you can follow what is happening and put everything together. If the same scene is played in the opposite direction, then most often it will not make sense. This is why time does not work the same way when it is turned back according to physical predictions.
Some scholars believe in a concept known as the arrow of time, meaning that time always moves in only one direction and that its reversal would change the nature of cause and effect. This is closely related to entropy, but we will not touch on it. However, it is likely that the theory of the arrow of time does not apply to quantum physics - very strange and unusual in nature.
If you are a professional goalkeeper, you have a good idea of where the ball moving at high speed will hit before it hits the target. Your brain uses observational information about the speed and trajectory of the ball to predict where it will eventually hit. In this case, we can also use this information to make predictions even when the arrow of time is reversed.
When it comes to one ball moving along a predictable path, causation works the same way in both directions. This is even easier to understand if you imagine dropping a soccer ball from a rooftop. If you were shown a photograph of a ball halfway between the roof of a building and the ground, you would easily predict which direction it will move forward or backward in time - down or up.
The stochastic process can be modeled in any time order. (a) The causal model takes past information ← x and uses it to make statistically accurate predictions about the conditional future behavior of the process P (→ X | ← X = ← x). (b) The retrocausal model copies the behavior of the system from the point of view of an observer scanning the results from left to right, colliding with Xt + 1 to Xt. In this way, it stores relevant information about the future → x to create a statistically accurate retrodication of the past P (← X | → X = → x). Causal asymmetry assumes a non-zero gap between the minimum memory required for any C + causal model and its retrocausal counterpart C- / Aki Honda / Center for Quantum Technologies, National University of Singapore
But what if we are not talking about straight lines and single arcs of the trajectory? What if we toss up the sparkle and take a photo at the moment when most of them reach their highest point? In theory, you could run a classic simulation to determine where each of them will fall when moving forward, but doing the same in the opposite direction would be much more difficult and would require a much more powerful computer processor.
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This is why the aforementioned researchers decided to find out if quantum computers perceive the arrow of time differently. In theory, it is possible that quantum computers will not experience the same causal asymmetry problems as humans and conventional computers, since they do not use our version of physics. As it turned out, this is indeed the case. At least according to the study published by the team.
They made physical predictions in classical and quantum systems to determine how much memory forward and backward computations require. Classical systems confirmed causal asymmetry, and reverse predictions required much more resources to conduct. But when the experiments were performed on a quantum computer system, the direction of the arrow of time did not matter. Quantum computers determine the effect of a cause in much the same way as the cause of the effect.
“The most exciting thing for us is the possible connection with the arrow of time. If causal asymmetry is present only in classical models, this suggests that our perception of cause and effect - and therefore time - may be the result of applying the classical explanation of events in a fundamental quantum world,”says Jane Thompson, one of the scientists working on the project.
That is, according to the study, our understanding of time is based on a very limited perception of how things actually work. The universe can be very ambiguous when it comes to Newton's laws of motion.
Vladimir Guillen