For a long time, it was believed that the laws of quantum mechanics only apply to tiny objects like photons. However, physicists have proved that very large bodies (by the standards of the molecular world) can obey these rules.
Probably, you have heard more than once about the thought experiment, which at one time was formulated by the Austrian physicist Erwin Schrödinger - the same one with a cat, a box and a radioactive isotope. According to the experimental conditions, a cat can be simultaneously dead and not dead, that is, it is in a state of a kind of quantum uncertainty - "superposition". Well, the scientists didn’t put cats in boxes, they just ran the same experiment with a huge molecule of 2,000 atoms.
Quantum superposition has been tested countless times on small systems, and physicists have successfully shown that individual particles can be in two places at the same time. But on a similar scale, this kind of experiment has never been done before.
This experiment allows researchers to refine hypotheses of quantum mechanics and better understand how this mysterious branch of physics actually works - as well as how the laws of quantum mechanics combine with the more traditional, larger-scale laws of classical physics. "Our results show excellent agreement with quantum theory and cannot be explained in terms of classical physics," the researchers argue in their paper.
In particular, the new research includes the Schrödinger equation, which describes how even individual particles can behave like waves and appear in several places at the same time. The easiest way to describe their interaction is like ripples in a pond into which you threw several stones at once.
To prove their hypothesis, the scientists set up an experiment with two slits - an experience well known to quantum physicists. It usually consists of projecting individual particles of light (photons) through two slits. If the photons were just acting like particles, the resulting projection of light to the other side would show just one stripe. But in reality, the light projected on the other side shows an interference pattern - many bands that interact like waves. As you can see, proof doesn't even require super sensitive hardware.
Experiment scheme.
It seems to us that the photons are in two places at the same time, like Schrödinger's cat. But, as many people know, a cat is in two states until it has an outside observer. When the box is opened, the state of the cat becomes certain - it is either alive or dead.
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It's the same with photons. As soon as the light is measured or observed directly by a person, the superposition disappears and the state of the photon is fixed. This is one of the main mysteries at the heart of all quantum mechanics.
The researchers repeated the experiment with two slits, but instead of using photons, they used electrons, atoms and small molecules. But now physicists have shown that huge molecules obey the same rules! The team used huge assemblies of atoms made up of 2,000 "parts" to create quantum interference patterns as if they were behaving like waves and were in more than one place at the same time.
These colossal molecules are known as "oligotetraphenylporphyrins enriched in fluoroalkylsulfanyl chains," and some of them were 25,000 times the mass of hydrogen atoms. But as the molecules grow in size, they also become less stable, which is why scientists have only been able to interfere with them for seven milliseconds at a time using a newly developed piece of equipment - a wave matter interferometer. Even factors such as the rotation of the Earth and the gravitational attraction of the atoms themselves had to be taken into account. Well, the work was worth it.
We now know that the rules of quantum mechanics apply not only to tiny objects like photons, but also to much larger bodies. The previous record was a molecule of only 800 atoms - it was believed that this is the limit after which, instead of the laws of quantum physics, the laws of classical physics begin to operate. But this is not the end: the team is confident that very soon it will be able to set a new record.
Vasily Makarov