A quantum experiment by scientists from the National University of Australia confirms the well-known theory that reality does not exist until an outside observer measures it.
At least this is true for very small scale objects.
The results of the experiment were published in the authoritative publication Nature Physics.
Researchers have tried to replicate a famous experiment that underlies quantum physics's very bizarre prediction about the nature of reality. According to this prediction, there is no reality until we measure it, at least on a very small scale.
For a common man in the street, this thesis evokes a feeling of "persistent delirium", and even with Einstein's general theory of relativity, many of the foundations of quantum theory have not yet been reconciled.
However, this does not prevent physicists from actively experimenting in this area, and actually working quantum computers have long surprised no one.
Reality doesn't exist
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The researchers asked themselves a simple question at first glance. If we are talking about an object that can behave either as a particle or as a wave, then at what moment in time does the object “decide” how to behave?
According to general logic, an object should be either a particle or a wave in its origin, and therefore it does not matter who makes measurements or observations of the object, since its nature will not change from this.
The experiment proves that observations of the atom in the future affect its behavior in the past
But according to quantum theory, this is not the case.
Quantum theory suggests that the outcome depends on how the object was measured at the end of its path.
And a group of Australian physicists in the course of their experiment found evidence that everything happens that way.
“Our research proves that measurement is everything. On a quantum level, reality doesn't exist if you can't see it,”concludes study leader Andrew Truscott, a physicist at the Australian National University in Canberra.
For the first time such an experiment was proposed by the American theoretical physicist John Wheeler in 1978. It is now known in science as Wheeler's Delayed Choice Experiment.
Wheeler suggested using rays of light reflected by mirrors, but at that time technology did not allow such an experiment to be carried out in full. Almost 40 years later, a group of Australian researchers were able to implement the idea of the Wheeler experiment using helium atoms interacting with laser beams.
The researchers trapped helium atoms in a "Bose-Einstein condensate" state that allows quantum effects to be observed at the macroscopic level, and then removed all but one of the atoms.
This single atom was then passed between two laser beams, which acted in the same role as the fine mesh acts for light beams. Those. in the role of an uneven lattice.
Then a second such "mesh" was added along the path of the atom.
This led to a distortion of the path of the atom, it went on both possible paths as a wave would. In other words, the atom took two different paths.
But in the repeated experiment, when the second “grid” was not added, the atom chose only one possible path.
According to the researchers, the fact that the second “grid” was added after the atom crossed the first “crossroads” suggests that the atom, figuratively speaking, did not define its nature before being observed (or measured) a second time.
“Quantum physics predictions about object interactions can seem odd when it comes to light that behaves like a wave,” explains Roman Khakimov, an Australian National University researcher who took part in the study.
But he says experiments with atoms that have mass and interact with electric fields make the picture even more incredible.
Simply put, if you accept the fact that the atom took a certain path at the first crossroads, the experiment proves that future measurements can influence the past of the atom, explains study leader Andy Truscott.
“The atom did not travel between the conditional points A and B,” he explains. “Only after measurements at the final point of observation did it become clear whether the atom behaved like a wave, splitting in two directions, or like a particle, choosing one.”
What does it mean?
Despite the fact that all this sounds crazy to the uninitiated person, the authors of the study say that the experiment is confirmation of quantum theory. At least on the smallest scale.
This theory has already made it possible to create a number of quite workable technologies in the field of lasers and computer processors, but so far there have been no such striking experiments confirming it.
Truscott and Khakimov essentially found confirmation that reality does not exist until we observe it.
This is one of the fundamental theses of quantum theory. It is his improbability from the point of view of the layman, for whom the rain does not stop falling, even if you close your eyes so as not to see it, that make the quantum theory “divorced from reality”.
So far, no evidence has been found that this principle works in reality. Wheeler's thought experiment, as well as the practical experiment of Truscott, which confirms it, so far belong only to the quantum level.
At the same time, a number of philosophers believe that even being inapplicable to the macro level, quantum theory can be useful for the layman, since (being roughly formulated) it says that the world is exactly as we see it.