Shulou(Shulou.com)11/24 Report--

We think that the main problem with quantum particles is that they are regarded as classical particles and their behavior is very non-classical. (or the problem is to think of quantum particles as "objects", a term first coined by Michael Michael Brooks. Many examples of "weirdness" brought about by quantum properties stem from the fact that, at least, many different interpretations of quantum mechanics bring about these oddities. However, no matter what quantum physicists are dealing with, objects that need to be described in quantum physics are not equal to classical objects, or even equal to or similar to things such as dust, sand or glass.

Quantum particles are much smaller than the classical particles we usually see, which is incredibly small. Because of this, almost (in Philip Ball's words), "everything is different on a quantum scale" (that is, not just weird). This means that it is problematic to use words in classical physical contexts such as "objects" and "particles". Even the word "wave" in quantum mechanics is often misleading. This is mainly because quantum wave functions are only mathematical objects represented by equations-strictly speaking, they do not exactly correspond to the description of reality.

More specifically, if the particles are waves, then the interference of waves is not so strange, and the superposition of waves is not so strange. (that is, it is also problematic to treat quantum x as a wave-- as just mentioned. )

Technically, quantum x (things that have not yet been named, temporarily expressed in letters because they don't have the right words) and quantum y interfere with each other-just like waves on the ocean. Therefore, when quantum x and quantum y interfere, they are superimposed on each other. Of course, classical objects cannot interfere with another classical object-at least not in the same way as quantum objects. Classical x and classical y cannot be superimposed.

However, we are not talking about classical objects or even classical particles here!

So why doesn't quantum x behave like classical objects or even classical particles? On the other hand, it would be strange if a classical object behaves like a quantum x. But that didn't happen. Many people think that quantum phenomena are strange, mainly because they treat them as classical phenomena, but their behavior is very non-classical. In fact, we only have quantum phenomena in a quantum way-just as classical phenomena are expressed in a classical way.

When Michael Brooks used the word "single positive nuclear charge, or proton", he showed us again the problem with the word "particle". We can certainly come up with a definition here, that is:

Proton = (single) positive nuclear charge

So, in this case, the particle is just a positive charge. Nowadays, positive (or negative) charges are difficult to be granular-at least when they exist in isolation, because they always show the characteristics of waves. Even if a proton (or another particle) contains properties other than charge (such as spin, mass, size, etc.), the word "particle" still seems inappropriate. But it's also useful!

If we go back to the description that a quantum object is a wave, one way to show the irrationality of this description (in many ways) is to clarify the de Broglie wavelength of the fullerene molecule (made up of 60 carbon atoms). Fullerene is a huge quantum "object", the size is about meters, or 1/1000000000000 meters! What does this have to do with waves on the ocean or any other type of classical (or macroscopic) waves?

The following discussion is as close as possible to classical particles in quantum mechanics.

When a wave becomes a particle,

As already mentioned, when two quantum waves meet, they superimpose. The superposition is the sum of two rows of waves at any given position. In addition, this "sum" can behave more like a particle than when two waves exist alone. (this is roughly in line with Max born's position in the 1920s and 1930s-see born's Law for details). This particle-like thing is the result of the superposition of two or more quantum waves. In other words, if you put one trough with another (or one peak with another), you will get something like a particle or entity. In other words, when a wave is squeezed, fused or mixed together, it becomes more like a hard entity.

Of course, all these words and descriptions are similar in nature!

In other words, we still use the words "wave" and "particle" (as well as "trough" and "peak", not to mention "squeeze", "fusion" and "mix") here. This is mainly because I have no choice but to do so.

In fact, all these words belong to the interpretation of quantum mechanics. This means that it is not very helpful to simply use monotonous variables x, y, etc., when interpreting quantum mechanics. Of course, this will not help any layman who is interested.

The body of the smoke dragon

Although Michael Brooks was quoted at the beginning of the article, he wrote elsewhere in the same book:

Bohr believes that the ultimate entity behind the Schrodinger wave equation is neither a wave nor a particle, so it cannot be described in any terms that we can deal with.

Of course, just because Brooks quotes Niels Bohr doesn't mean he agrees with Bohr. Nevertheless, Bohr does raise a problem that needs to be addressed-even if people do not need to accept his overall position or explanation. Many people do disagree with Bohr-especially physicists such as Albert Einstein and later David Bohm. )

John Wheeler (John Archibald Wheeler,1911--2008) John Archibald Wheeler, an American theoretical physicist, has studied these problems, or at least similar ones. He used the image of "smoke dragon" to express his views. He points out that between experimental input and experimental output (or observation), "we have no right to talk about what exists." As a result, words such as "particles" and "waves" are naturally suspected-at least when they are used in experiments (that is, the hypothetical "authenticity" of the dragon's body).

Therefore, there is a difference between describing quantum x as a "particle" or "wave" before the output (that is, what exists and occurs before the actual experiment or observation) and describing quantum x in this way after the experiment or observation output. However, even if experiments (or observations) have been carried out, that is, when the quantum wave function has "collapsed", it may still be problematic to use these classical words.

To quote Bohr again. According to Brooks, Bohr believes

Once the measurement is made, the type of measurement will determine what we can see.

More importantly,

For example, if you use an instrument to detect the position of an object in space, you will see an object that has a definite position in space-- an entity that we call a particle.

The point here is that it is suspicious to use the word "particle" to refer to something on the dragon's body, and to refer to something after "the spatial location of the object detected by the instrument". So this (ontological? ) x is not a particle before measurement or observation, nor is it a particle after measurement (or observation).

All in all: the classical word "particle" is problematic in all quantum cases.

Note:

If it is a problem to treat a quantum particle as a particle (or an object), then it is also a problem to think of an atom as a particle.

Perhaps an atom cannot be regarded as an "object" at all. After all, if the nucleus of a helium atom is considered the size of a lemon, the edge of the atom (defined by the outer orbit of its electrons) will be 2.5 miles in diameter. Therefore, proportionally, the nucleus is extremely out of proportion to the whole atom. Each electron in an atom is incredibly small compared to the atom to which it belongs. (equivalent to a dot on a circle 2.5 miles in diameter. Even smaller! There is no exact statement about the size of electrons at present. )

Of course, most or even all (classical) entities are made up of individual element atoms, so there is no problem in itself.

Original link: Quantum Particles are Neither Classical Particles Nor Weird Objects

The content of the translation only represents the author's point of view, not the position of the Institute of Physics of the Chinese Academy of Sciences.

This article comes from the official account of Wechat: Institute of Physics, Chinese Academy of Sciences (ID:cas-iop), author: Paul Austin Murphy, translation: Nothing, revision: Tibetan idiots, editors: Tibetan idiots

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