Researchers from the Moscow Institute of Physics and Technology together with colleagues from the United States were able to reverse the quantum computer by the arrow of time, thermodynamically turning the time back. In addition, they calculated the likelihood of an electron in interstellar space spontaneously observed time travel.
The second law of thermodynamics shows that entropy in a closed system does not decrease with time. Therefore, for example, heat cannot pass from a colder body to a warmer one, but only vice versa.
Arrow of time
Therefore, in accordance with the laws of physics, for the most part, we cannot distinguish between the past and the future, and in fact, all processes in the macrocosm develop only according to the “arrow of time”. A snooker ball breaks the pyramid of snooker balls, but the pyramid cannot assemble back on its own; a kettle cools in a cold room, but does not heat up in a cold one, and so on. In other words, any closed system (without the influx of energy from the outside) either maintains its state, or spontaneously moves towards chaos, but not order. The second option happens much more often than the first one.
The physicists decided to check whether it is possible that time itself will turn back at least for an individual particle and at least for a split second. First, they conducted an experiment with a single electron in empty interstellar space. Initially, its location was localized (a small area of space is defined where it can be located).
However, in the second law of thermodynamics, a part of the space in which the electron is localized spreads out in a fraction of a second, and over time we will know less and less about the specific location of the electron.
This is similar to the increase in the entropy of a large system, which is described by the second law of thermodynamics.
Back in time
According to their findings published in Scientific Reports, the researchers focused on the reverse process, when an electron, smeared in a small fraction of a second, spontaneously localizes in a smaller volume of space. They calculated the probability with which, according to the Schrödinger equation, this process proceeds. It turned out that if every second, one observes 10 billion of just localized electrons in empty space, it will be possible to see such a turn of the arrow of time only once in 13.7 billion years of attempts. At the same time, the “depth” of such a “time travel” will not exceed one ten-billionth of a second. The probability of observing such an event using the example of one electron is very small. And since there are a lot of particles in the bodies of the macrocosm, this probability becomes even smaller.
Read also: 10 Time Travel Possible Proof
Then the scientists tried to turn the time back in the experiment. Instead of an electron, they observed the state of a quantum computer, first of two, and then of three superconducting qubits.
First, all qubits were transferred to the state “0”, the main one. At that moment, all the electrons in it were localized in a small area of space. They can be compared with snooker balls, which are built in a pyramid. Then, the stage of degradation of the system comes.
Just as the electron spreads in space, and the pyramid is broken by the impact, the state of the qubits begins to complicate in a bizarre way. For this, a computer program for the evolution of the state of qubits is launched for a short time. Such degradation would occur due to interaction with the environment because the system tends to chaos. But the controlled nature of the autonomous evolution program of the system will make the last stage of the experiment possible.
Then the arrow of time is reversed. A special program transforms the state of a quantum computer so that in the future it develops the other way around, from chaos to order. This operation is similar to the random fluctuations of the field in the case of an electron, but now in the quantum computer, the authors of the work have launched it intentionally. Again, we will draw an analogy with the snooker pyramid: imagine that someone shook the table with infinitely accurate calculation, so as to gather parted balls into one pyramid again.
In the end, at the stage of regeneration, physicists re-launched the same evolution program, due to which chaos was growing. And the system of qubits begins to wind back, into the past, as if the blurred electron again “gathered” in a small volume, and the balls, having passed backwards from the past along their paths, formed into a pyramid.