What animal is mentioned in Schrödinger's experiment. The story of Schrödinger's cat, who suffered for science. Or not injured - physicists still cannot agree. A few words about quantum mechanics

- a thought experiment by physicist Erwin Schrödinger, the essence of which is that the cat in the box is both alive and dead. Thus, the scientist proved the incompleteness of quantum mechanics in the transition from subatomic systems to macroscopic ones.

Origin

Austrian theoretical physicist Erwin Schrodinger in 1935 in the article “The current situation in quantum mechanics” (Die gegenwärtige Situation in der Quantenmechanik) proposed an experiment with a cat in a box in Naturwissenschaften.

We take a cat and put it in a box. The box contains an atomic nucleus and a container with poisonous gas. The probability of nuclear disintegration is 50%, if it takes place, the gas container will open and the cat will die. If decay does not occur, the cat is alive. According to the basics of quantum mechanics, before we open the box, the cat is in a state of quantum superposition - that is, in all states at the same time.

It turns out that in the “cat-core” system, the cat can be alive or dead with the same probability of 50%. Or he is both alive and dead at the same time.

Popularity on the Internet

For the first time on the Internet, the issue of Schrödinger's cat was discussed in May 1990 on the Usenet's sci.physics forum. On August 9, 2000, a poem dedicated to Schrödinger's cat was published on the Straight Dope Q&A forum.

In August 2004, ThinkGeek began selling T-shirts that read "Schrödinger's cat is dead."

On January 4, 2006, a Schrödinger comic was released in the Xkcd comic series.

” – The last panel of this comic is funny and unfunny at the same time. Until you read it, you can't tell how it will turn out in the end.

- Heck"

On June 2, 2007, I Can Has Cheezburger published a picture of a cat in a box with the caption: "In your quantum box... one cat... maybe."

The crowning glory of Schrödinger's cat was the Google Doodle dedicated to him, which appeared on August 12, 2013 - on the day of Erwin Schrödinger's 126th birthday.

References in popular culture

A significant role in the popularization of Schrödinger's cat in popular culture was played by films, TV shows, books and computer games where this experiment was mentioned. Let's just give some examples.

In the 16th episode of the sixth season of Futurama, Schrödinger and his cat are detained by the police.

In the second episode of the first season of Rick and Morty, the main characters meet Schrodinger's cats in a parallel reality.

Sheldon Cooper, in The Big Bang Theory, used Schrödinger's cat theory to explain to Penny how relationships between men and women work.

Meaning

Schrödinger's cat is not only an Internet meme, but also a hero of popular culture. A cat that is both alive and dead at the same time symbolizes a certain ambiguity. Schrödinger is remembered when something is both funny and not, or when something is both forbidden and allowed. For example, a traffic light with a red and green signal on at the same time is a Schrödinger traffic light.

Gallery

The article describes what the Schrödinger theory is. The contribution of this great scientist to modern science, as well as a thought experiment invented by him about a cat. The area of application of this kind of knowledge is briefly outlined.

Erwin Schrödinger

The notorious cat, which is neither alive nor dead, is now being used everywhere. Films are made about him, communities about physics and animals are named after him, there is even such a clothing brand. But most often people mean the paradox with the unfortunate cat. But about its creator, Erwin Schrödinger, as a rule, they forget. He was born in Vienna, which was then part of Austria-Hungary. He was the son of a highly educated and wealthy family. His father, Rudolf, produced linoleum and invested money in science as well. His mother was the daughter of a chemist, and Erwin often went to listen to his grandfather's lectures at the academy.

Since one of the scientist's grandmothers was an Englishwoman, from childhood he was interested in foreign languages and was fluent in English. Not surprisingly, at school, Schrödinger was the best in class every year, and at the university he asked difficult questions. In the science of the beginning of the twentieth century, inconsistencies between the more understandable classical physics and the behavior of particles in the micro- and nanoworld were already revealed. To resolve the emerging contradictions and threw all his strength

Contribution to science

To begin with, it is worth saying that this physicist was engaged in many areas of science. However, when we say "Schrödinger's theory", we do not mean the mathematically coherent description of color created by him, but his contribution to quantum mechanics. In those days, technology, experiment and theory went hand in hand. Photography developed, the first spectra were recorded, and the phenomenon of radioactivity was discovered. The scientists who received the results closely interacted with the theorists: they agreed, complemented each other, and argued. New schools and branches of science were created. The world began to play with completely different colors, and humanity received new mysteries. Despite the complexity of the mathematical apparatus, to describe what the Schrödinger theory is, plain language can.

The quantum world is easy!

It is now well known that the scale of the studied objects directly affects the results. Objects visible to the eye obey the concepts of classical physics. Schrödinger's theory is applicable to bodies one hundred by one hundred nanometers in size and less. And most often we are talking in general about individual atoms and smaller particles. So, each element of microsystems simultaneously has the properties of both a particle and a wave (particle-wave dualism). From the material world, electrons, protons, neutrons, etc. are characterized by mass and the inertia, speed, and acceleration associated with it. From the theoretical wave - parameters such as frequency and resonance. In order to understand how this is possible at the same time, and why they are inseparable from each other, scientists needed to reconsider the whole idea of the structure of substances in general.

Schrödinger's theory implies that mathematically these two properties are related through a construct called the wave function. Finding a mathematical description of this concept brought Schrödinger the Nobel Prize. However, the physical meaning that the author attributed to it did not coincide with the ideas of Bohr, Sommerfeld, Heisenberg and Einstein, who founded the so-called Copenhagen Interpretation. This is where the cat paradox came from.

wave function

When it comes to the microcosm elementary particles, lose the meaning of concepts inherent in macroscales: mass, volume, speed, size. And unsteady probabilities come into their own. Objects of such dimensions cannot be fixed by a person - only indirect ways of studying are available to people. For example, streaks of light on a sensitive screen or on a film, the number of clicks, the thickness of the sprayed film. Everything else is the area of calculations.

Schrödinger's theory is based on the equations that this scientist deduced. And their integral component is the wave function. It unambiguously describes the type and quantum properties of the particle under study. It is believed that it shows the state, for example, of an electron. However, she herself, contrary to the ideas of her author, physical sense does not have. It's just a handy math tool. Since our article presents the Schrödinger theory in simple words, say that the square of the wave function describes the probability of finding the system in a predetermined state.

Cat as an example of a macro object

With this interpretation, which is called Copenhagen, the author himself did not agree until the end of his life. He was disgusted by the vagueness of the concept of probability, and he insisted on the visibility of the function itself, and not its square.

As an example of the inconsistency of such ideas, he argued that in this case the microworld would influence macroobjects. The theory says the following: if a living organism (for example, a cat) and a capsule with poisonous gas are placed in a sealed box, which opens if a certain radioactive element decays, and remains closed if decay does not occur, then before opening the box we get a paradox. According to quantum concepts, an atom of a radioactive element will decay with a certain probability over a certain period of time. Thus, before experimental discovery, the atom is both intact and not. And, as Schrödinger's theory says, by the same degree of probability, the cat is both dead and otherwise alive. Which, you see, is absurd, because, having opened the box, we will find only one state of the animal. And in a closed container, next to the deadly capsule, the cat is either dead or alive, since these indicators are discrete and do not imply intermediate options.

There is a concrete but not yet fully proven explanation for this phenomenon: in the absence of time-limiting conditions for determining the specific state of a hypothetical cat, this experiment is undoubtedly paradoxical. However, quantum mechanical rules cannot be used for macroobjects. It has not yet been possible to draw a precise line between the microcosm and the ordinary. Nevertheless, an animal the size of a cat is, without a doubt, a macro object.

Applications of quantum mechanics

As for any, even theoretical, phenomenon, the question arises of how Schrödinger's cat can be useful. The big bang theory, for example, is based precisely on the processes involved in this thought experiment. Everything that relates to ultra-high speeds, the ultra-small structure of matter, the study of the universe as such, is explained, among other things, by quantum mechanics.

In 1935, an ardent opponent of the newly emerging quantum mechanics, Eric Schrödinger, published an article that intended to denounce and prove the failure of a new branch of the development of physics.

The essence of the article is conducting a thought experiment:

A live cat is placed in a completely sealed box.
A Geiger counter containing one radioactive atom is placed next to the cat.
A flask filled with acid is attached directly to the Geiger counter.
The eventual decay of a radioactive atom will set off a Geiger counter, which in turn will break the flask and the acid that spills out of it will kill the cat.
Will the cat live or die if he is with such uncomfortable neighbors?
One hour is allotted for the experiment.

Answer to this question and was called upon to prove the inconsistency of quantum theory, which is based on superposition: the law of paradox - all the microparticles of our world are always in two states at the same time, until they begin to observe them.

That is, being in a closed space (quantum theory), our cat, like its unpredictable neighbor - an atom, are synchronously present in two states:

A live and dead cat at the same time.
Decayed, and at the same time not decayed atom.

Which, according to classical physics, is a complete absurdity. It is impossible for such mutually exclusive things to exist simultaneously.

And this is correct, but only from the point of view of the macrocosm. Whereas completely different laws operate in the microcosm, and therefore Schrödinger was mistaken when applying the laws of the macrocosm to relations within the microcosm. Not realizing that purposeful observation of the ongoing uncertainties of the microworld eliminates the latter.

In other words, if we open a closed system in which a cat is placed along with a radioactive atom, we will see only one of the possible states of the test subject.

This was proved by an American physicist from the University of Arkansas, Art Hobson. According to his theory, if you combine a microsystem (radioactive atom) with a macrosystem (Geiger counter), the latter will definitely be imbued with the state of quantum entanglement of the former and go into superposition. And, since we cannot directly observe this phenomenon, it will become unacceptable for us (which Schrödinger argued).

So, we found out that the atom and the radiation counter are in the same superposition. Then who or what, for this system, can be called a cat? If you think logically, the cat, in this case, becomes an indicator of the state of the radioactive nucleus (simply - an indicator):

The cat is alive, the core has not disintegrated.
The cat is dead, the core has disintegrated.

However, we must take into account the fact that the cat is also part of a single system, since it is also inside the box. Therefore, according to quantum theory, the cat is in the so-called non-local connection with the atom, i.e. confused, and hence in the superposition of the microworld.

It follows from this that, with a sudden change in one of the objects of the system, it will also happen with another object, no matter how far apart they are. The instantaneous change in the state of both objects proves that we are dealing with a single system, simply divided by space into two parts.

So, we can say with confidence that Schrödinger's cat is momentarily either alive if the atom has not decayed, or dead if the atom has decayed.

And yet, it was thanks to Schrödinger's thought experiment that a mathematical device was constructed that describes the superposition of the microworld. This knowledge is found wide application in cryptography and computer technologies.

Finally, I would like to note the inexhaustible love for the mysterious paradox of "Schrödinger's cat" on the part of all kinds of writers and cinema. That's just a few examples:

A magical device called "Schrödinger's Cat" in Lukyanenko's novel "The Last Watch".
In the detective novel Dirk Gently's Detective Agency by Douglas Adams, there is a lively discussion of the problem of Schrödinger's cat.
In the novel by R. E. Heinlein "The Cat Passing Through Walls", the protagonist, a cat, is almost constantly in two states at the same time.
Lewis Carroll's famous Cheshire cat in Alice's Adventures in Wonderland loves to appear in several places at once.
In the novel Fahrenheit 451, Ray Bradbury raises the question of Schrödinger's cat, in the form of a living-dead mechanical dog.
In The Mage Healer, Christopher Stashef describes his vision of Schrödinger's cat in a very peculiar way.

And many other enchanting, completely impossible ideas about such a mysterious thought experiment.

To my shame, I want to admit that I heard this expression, but did not know at all what it meant and at least on what topic it was used. Let me tell you what I read on the Internet about this cat ...

« Shroedinger `s cat"- this is the name of the famous thought experiment of the famous Austrian theoretical physicist Erwin Schrödinger, who is also a laureate Nobel Prize. With the help of this fictitious experiment, the scientist wanted to show the incompleteness of quantum mechanics in the transition from subatomic systems to macroscopic systems.

The original article by Erwin Schrödinger was published in 1935. Here is the quote:

You can also construct cases in which burlesque is enough. Let some cat be locked in a steel chamber, along with the next diabolical machine (which should be regardless of the intervention of the cat): inside the Geiger counter is a tiny amount radioactive substance, so small that only one atom can decay within an hour, but with the same probability it may not decay; if this happens, the reading tube is discharged and a relay is activated, lowering the hammer, which breaks the cone of hydrocyanic acid.

If we leave this whole system to itself for an hour, then we can say that the cat will be alive after this time, as long as the atom does not decay. The first decay of an atom would have poisoned the cat. The psi-function of the system as a whole will express this by mixing in itself or smearing the living and dead cat (forgive the expression) in equal proportions. Typical in such cases is that the uncertainty, originally limited to the atomic world, is transformed into a macroscopic uncertainty that can be eliminated by direct observation. This prevents us from naively accepting the "blur model" as reflecting reality. By itself, this does not mean anything unclear or contradictory. There is a difference between a fuzzy or out-of-focus photo and a cloud or fog shot.

In other words:

There is a box and a cat. The box contains a mechanism containing a radioactive atomic nucleus and a container of poisonous gas. The experimental parameters are chosen so that the probability of nuclear decay in 1 hour is 50%. If the core disintegrates, the gas container opens and the cat dies. If the disintegration of the nucleus does not occur, the cat remains alive and well.
We close the cat in a box, wait an hour and ask ourselves: is the cat alive or dead?
Quantum mechanics, as it were, tells us that the atomic nucleus (and hence the cat) is in all possible states at the same time (see quantum superposition). Before we opened the box, the "cat-core" system is in the state "the core has decayed, the cat is dead" with a probability of 50% and in the state "the nucleus has not decayed, the cat is alive" with a probability of 50%. It turns out that the cat sitting in the box is both alive and dead at the same time.
According to the modern Copenhagen interpretation, the cat is still alive / dead without any intermediate states. And the choice of the decay state of the nucleus occurs not at the moment of opening the box, but even when the nucleus enters the detector. Because the reduction of the wave function of the "cat-detector-nucleus" system is not connected with the human observer of the box, but is connected with the detector-observer of the nucleus.

According to quantum mechanics, if the nucleus of an atom is not observed, then its state is described by a mixture of two states - a decayed nucleus and an undecayed nucleus, therefore, a cat sitting in a box and personifying the nucleus of an atom is both alive and dead at the same time. If the box is opened, then the experimenter can see only one specific state - "the nucleus has disintegrated, the cat is dead" or "the nucleus has not disintegrated, the cat is alive."

Essence in human language: Schrödinger's experiment showed that, from the point of view of quantum mechanics, a cat is both alive and dead at the same time, which cannot be. Consequently, quantum mechanics has significant flaws.

The question is this: when does a system cease to exist as a mixture of two states and chooses one concrete one? The purpose of the experiment is to show that quantum mechanics is incomplete without some rules that specify under what conditions the wave function collapses, and the cat either becomes dead or remains alive, but ceases to be a mixture of both. Since it is clear that the cat must necessarily be either alive or dead (there is no intermediate state between life and death), this will be the same for atomic nucleus. It must necessarily be either broken up or not broken up (Wikipedia).

Another most recent interpretation of Schrödinger's thought experiment is the story of Big Bang Theory's Sheldon Cooper, who spoke to Penny's less educated neighbor. The point of Sheldon's story is that the concept of Schrödinger's cat can be applied to relationships between people. In order to understand what is happening between a man and a woman, what kind of relationship between them: good or bad, you just need to open the box. Until then, relationships are both good and bad.

Below is a video clip of this Big Bang Theory dialogue between Sheldon and Peny.

Schrödinger's illustration is the best example to describe the main paradox of quantum physics: according to its laws, particles such as electrons, photons, and even atoms exist in two states at the same time ("alive" and "dead", if you remember the long-suffering cat). These states are called superpositions.

American physicist Art Hobson (Art Hobson) from the University of Arkansas (Arkansas State University) offered his solution to this paradox.

"Measurements in quantum physics are based on the operation of certain macroscopic devices, such as the Geiger counter, which determine the quantum state of microscopic systems - atoms, photons and electrons. Quantum theory implies that if you connect a microscopic system (particle) to some macroscopic device that distinguishes between two different states of the system, then the device (Geiger counter, for example) will go into a state of quantum entanglement and will also be simultaneously in two superpositions. However, it is impossible to observe this phenomenon directly, which makes it unacceptable,” says the physicist.

Hobson says that in Schrödinger's paradox, the cat plays the role of a macroscopic device, a Geiger counter, connected to a radioactive nucleus to determine the state of decay or "non-decay" of this nucleus. In this case, a live cat will be an indicator of "non-decay", and a dead cat - an indicator of decay. But according to quantum theory, the cat, like the nucleus, must be in two superpositions of life and death.

Instead, according to the physicist, the quantum state of the cat must be entangled with the state of the atom, which means that they are in a "non-local connection" with each other. That is, if the state of one of the entangled objects suddenly changes to the opposite, then the state of its pair will also change in the same way, no matter how far apart they are. At the same time, Hobson refers to the experimental confirmation of this quantum theory.

“The most interesting thing about the theory of quantum entanglement is that the change in the state of both particles occurs instantly: no light or electromagnetic signal would have time to transfer information from one system to another. So you can say that it is one object divided into two parts by space, no matter how great the distance between them is,” explains Hobson.

Schrödinger's cat is no longer alive and dead at the same time. He is dead if decay happens, and alive if decay never happens.

We add that similar solutions to this paradox have been proposed by three more groups of scientists over the past thirty years, but they were not taken seriously and remained unnoticed in the broad scientific community. Hobson notes that the solution of the paradoxes of quantum mechanics, at least theoretical, is absolutely necessary for its deep understanding.

Schrödinger

And just recently, THEORETICS EXPLAINED HOW GRAVITY KILLS SCHROEDINGER'S CAT, but this is already more complicated ...

As a rule, physicists explain the phenomenon that superposition is possible in the world of particles, but impossible with cats or other macro objects, interference from environment. When a quantum object passes through a field or interacts with random particles, it immediately assumes just one state - as if it were measured. This is how the superposition collapses, as scientists believed.

But even if in some way it became possible to isolate the macroobject, which is in a state of superposition, from interactions with other particles and fields, then it would still sooner or later take on a single state. At least, this is true for the processes occurring on the surface of the Earth.

“Somewhere in interstellar space, maybe a cat would have a chance to maintain quantum coherence, but on Earth or near any planet this is extremely unlikely. And the reason for this is gravity,” explains the lead author of the new study, Igor Pikovski (Igor Pikovski) from the Harvard-Smithsonian Center for Astrophysics.

Pikovsky and his colleagues from the University of Vienna argue that gravity has a destructive effect on quantum superpositions of macroobjects, and therefore we do not observe such phenomena in the macrocosm. The basic concept of the new hypothesis, by the way, is briefly outlined in the feature film Interstellar.

Einstein general theory relativity says that extremely massive object will bend space-time near itself. Considering the situation at a smaller level, we can say that for a molecule placed near the surface of the Earth, time will go somewhat slower than for one that is in the orbit of our planet.

Due to the influence of gravity on space-time, a molecule that falls under this influence will experience a deviation in its position. And this, in turn, should also affect its internal energy - vibrations of particles in a molecule, which change over time. If a molecule is introduced into a state of quantum superposition of two locations, then the relationship between position and internal energy would soon force the molecule to "choose" only one of the two positions in space.

“In most cases, the phenomenon of decoherence is associated with an external influence, but in this case, the internal vibration of the particles interacts with the movement of the molecule itself,” Pikovsky explains.

This effect has not yet been observed, since other sources of decoherence, such as magnetic fields, thermal radiation and vibrations tend to be much stronger, and cause quantum systems to break down long before gravity does. But experimenters seek to test the stated hypothesis.

A similar setup could also be used to test the ability of gravity to destroy quantum systems. To do this, it will be necessary to compare the vertical and horizontal interferometers: in the first, the superposition will soon disappear due to the dilation of time at different "heights" of the path, while in the second, the quantum superposition may persist.

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Surely you have heard more than once that there is such a phenomenon as "Schrödinger's Cat". But if you are not a physicist, then, most likely, you only remotely imagine what kind of cat it is and why it is needed.

« Shroedinger `s cat”- this is the name of the famous thought experiment of the famous Austrian theoretical physicist Erwin Schrödinger, who is also a Nobel Prize winner. With the help of this fictitious experiment, the scientist wanted to show the incompleteness of quantum mechanics in the transition from subatomic systems to macroscopic systems.

In this article, an attempt is made to explain in simple terms the essence of Schrödinger's theory about the cat and quantum mechanics, so that it is accessible to a person who does not have a higher technical education. The article will also present various interpretations of the experiment, including those from the Big Bang Theory series.

Description of the experiment

The original article by Erwin Schrödinger was published in 1935. In it, the experiment was described using or even personified:

You can also construct cases in which burlesque is enough. Let some cat be locked in a steel chamber, along with the following diabolical machine (which should be independent of the intervention of the cat): inside the Geiger counter is a tiny amount of radioactive material, so small that only one atom can decay in an hour, but with the same the probability may not fall apart; if this happens, the reading tube is discharged and a relay is activated, lowering the hammer, which breaks the cone of hydrocyanic acid.

In other words:

There is a box and a cat. The box contains a mechanism containing a radioactive atomic nucleus and a container of poisonous gas. The experimental parameters are chosen so that the probability of nuclear decay in 1 hour is 50%. If the core disintegrates, the gas container opens and the cat dies. If the disintegration of the nucleus does not occur, the cat remains alive and well.
We close the cat in a box, wait an hour and ask ourselves: is the cat alive or dead?
Quantum mechanics, as it were, tells us that the atomic nucleus (and hence the cat) is in all possible states at the same time (see quantum superposition). Before we opened the box, the "cat-core" system is in the state "the core has decayed, the cat is dead" with a probability of 50% and in the state "the nucleus has not decayed, the cat is alive" with a probability of 50%. It turns out that the cat sitting in the box is both alive and dead at the same time.
According to the modern Copenhagen interpretation, the cat is still alive / dead without any intermediate states. And the choice of the decay state of the nucleus occurs not at the moment of opening the box, but even when the nucleus enters the detector. Because the reduction of the wave function of the "cat-detector-nucleus" system is not connected with the human observer of the box, but is connected with the detector-observer of the nucleus.

Explanation in simple words

The question is this: when does a system cease to exist as a mixture of two states and chooses one concrete one? The purpose of the experiment is to show that quantum mechanics is incomplete without some rules that specify under what conditions the wave function collapses, and the cat either becomes dead or remains alive, but ceases to be a mixture of both. Since it is clear that the cat must necessarily be either alive or dead (there is no intermediate state between life and death), this will be the same for the atomic nucleus. It must necessarily be either broken up or not broken up (Wikipedia).

Video from The Big Bang Theory

Below is a video clip of this Big Bang Theory dialogue between Sheldon and Peny.

Was the cat still alive as a result of the experiment?

For those who did not read the article carefully, but still worries about the cat - good news: do not worry, according to our data, as a result of a thought experiment by a crazy Austrian physicist

NOT A SINGLE CAT WERE INJURED