What is the Many Worlds Interpretation of Quantum Mechanics?

The standard way of understanding quantum physicsis the Copenhagen interpretation proposed by Niels Bohr, one of the founders of modern physics. According to the interpretation, the quantum world is completely separate from our ubiquitous experience, moreover, it begins with a paradox. Bohr's interlocutor was his graduate student theoretical physicist Werner Heisenberg. Together they discussed both real and thought experiments, considering suggestions and objections from Einstein, Schrödinger, Pauli, Paul Dirac and others. Heisenberg, for example, believed that the only correct interpretation should follow from the quantum theory, which can be proved in the process of further research. Einstein, however, could not reconcile himself to the implication of this assumption - the existence of "parallel universes" in each of which the same laws of nature apply. Indeed, such assumptions are not easy to reconcile with our perception of the universe.

If there are many worlds, then what are we doing in them?

In two places at the same time

One of the strangest ideas that appeared inphysics of the 20th century, is a many-worlds interpretation of quantum mechanics that attempts to explain the mysterious and contradictory effects of this theory. According to the Copenhagen Interpretation, every physical experiment, regardless of whether it refers to the phenomena of everyday life or to the phenomena of atomic physics, must be described in terms of classical physics. Together they form the language by which we describe our experiences and results.

But there is nothing to replace these concepts, and theyapplicability is limited by the uncertainty relation. It turns out that we must keep in mind the limited applicability of classical concepts and not try to go beyond this limitation. And in order to better understand this paradox, it is necessary to compare the interpretation of experience in classical and quantum physics.

Some physicists believe that there may be different particles, different forces, even a different number of dimensions of space compared to what we see around us.

The phenomena in question are similar to quantuminterference, in which a quantum particle passing through a double slit creates an interference pattern, which can only happen if the particle passes through both slits at the same time.

The many worlds interpretation explains this state of affairs with the idea of ​​what is actually in the experiment two universes involved Recall that the phenomenon of interference occurs when two or more waves of the same frequency, propagating in different directions, interact.

In one of these universes, a particle passes throughone slot, while the other passes through the second. Otherwise, these universes are identical. The interference pattern arises because these universes are in a quantum superposition.

This is interesting: Can quantum mechanics explain the existence of space-time?

Copenhagen interpretation

So the many worlds interpretation says that whatever can happen is actually takes place in a parallel universe. Thus, there must be an infinite number of parallel universes containing everything that could ever happen. In one of these universes you are a politician, in another a famous musician.

I agree, this idea is not easy to accept, especiallydue to other problems with the interpretation of many worlds. Thus, it predicts that all possible outcomes do happen, but does not explain why physicists see the most likely outcome a hundred times more often than others. For this reason, many scientists remain unconvinced and continue to look for more plausible interpretations.

Quantum entanglement is a phenomenon we can't explain

One of these was proposed by physicists from the universityGriffith in Australia. They believe they have found an alternative interpretation that solves the conflicting problems of quantum mechanics and is able to explain the strange strange results of scientific research.

At first glance, the new interpretation hassome resemblance to the many-worlds interpretation, suggesting the real existence of many different parallel universes. But there are important differences - each of these universes develops in accordance with classical Newtonian physics, the researchers note.

However, these universes can interactthrough "repulsion", which prevents particles in different universes from coming close to each other. “All quantum-like effects arise due to the existence of this interaction,” the authors of the scientific work write. "In the absence of inter-world interaction, worlds develop independently in accordance with purely Newtonian dynamics."

More on the topic: Does quantum mechanics suggest multiple worlds, or what is Everett's interpretation?

So how many universes are there?

Researchers claim that according to quantumtheory, there may be "many interacting worlds". This statement immediately solves the problem of probability, since quantum probabilities do not play any role in any of the worlds. Paradoxically, physicists say that "probabilities arise only because observers do not know what world they are actually in."

It turns out that the worlds develop differently, depending on what actually happens in each of them. This allows them to be grouped into classes according to macroscopic results.

no one knows exactly what quantum processes in the real world are responsible for weaving the fabric of space-time.

Physicists continue to study a number of examples in whichthe repulsive interaction between different worlds leads to the different quantum effects they see. In the interpretation of the many interacting worlds, physicists imagine two parallel worlds, in each of which the particle is directed towards the barrier. In one world, the particle bounces off it, but in another, the repulsion between the particles gives the second momentum needed to overcome the barrier.

According to the authors of the study, the increase in the number of worlds is more like predicted by quantum mechanics.

Yet there are still many challenges ahead.Perhaps most serious, and therefore most interesting, is how the many interacting worlds interpretation deals with quantum entanglement.

We talked about what it is here in more detail.

Original Copenhagen interpretationquantum mechanics is still popular, and the new theory could lead to testable predictions. The key lies in the number of worlds that actually make up the universe or multiverse. But if it is so that the matter does not end with two universes, their number tends to infinity.

If there are other universes, how many are there?

But if there is a finite number of worlds, thensooner or later scientists will be able to prove it. Of course, this will take time, but the results are definitely worth checking and our expectations. The idea of ​​a multiverse is becoming popular, and quantum mechanics is our key to finding other worlds. And what do you think, if a parallel universe exists, how did your life develop in it? We will wait for the answer here, as well as in the comments to this article.