5 ms·
I did my M.Sc. in quantum physics, and I'll be the first to admit I don't understand it. Yes, the equations do seem to predict what we observe in experiments v
by beloch 7y ago
I did my M.Sc. in quantum physics, and I'll be the first to admit I don't understand it.
Yes, the equations do seem to predict what we observe in experiments very well. Shockingly well, given how strange some of the predictions made by them are! However, we lack an intuitive understanding of why the equations work. Matter and energy behave very differently on the quantum scale than they do on the macroscopic scales we're used to observing. If you're trying to model a pendulum, your intuition about how objects behave in the real world can be of immense help when performing sanity checks on your equations. Your intuition is worse than useless when it comes to quantum systems. It's not just flat-out wrong much of the time, it can lead you to ignore things that should not be ignored.
Quantum physics has all sorts of English language, short-hand descriptions for mathematical functions like "tunnelling", "non-local", "spooky action at a distance" or, as is pertinent to this article "observation". You may think you understand what these mean, but you're probably at least partly wrong if you're thinking about them in terms of human language, natural human intuition, or even the very specific short-hand terminology of physicists. We are continually teasing out nuances in the math that language simply does not capture. If we lack the language to adequately describe reality, can we really understand it?
Feynman was very correct to observe that people who think they understand quantum physics on a deep, intuitive level, probably do not. Doing quantum physics with a human brain evolved for bashing stones together is like trying to breathe in outer space. It's possible with considerable effort and the right tools (e.g. a space-suit), but if you ever forget that it's a deeply unnatural thing to be doing you're probably going to get yourself into trouble.
- jshaqaw 7y agoI ask you because I definitely do not have an M. Sc. In quantum mechanics - at the lowest level of any system isn’t it inevitable that there is no deeper understanding. At a certain point you have hit the base level and things just “are.” Correct me if this is erroneous!
- platz 7y agoThis is a bigger question than physics can answer. The project of hard science is essentially reductionist and based on predicting events based on hypothesis. Your question is more logical or philosophical. Logic may have something to say about open or closed systems, but mapping that onto the real world will always be a following question.
- shkkmo 7y agoIt seems to me the limited hypothesis "We have reached a point where no further progress can be made in understanding why quantum mechanics works the way it does" is falsifiable and thus not purely logical or philosophical. (i.e. quantum mechanics is the lowest level of physics). It is only the broad hypothesis that is only answerable in philosophy: "There is a point in physics where no further progress can be made in understanding why things work the way they do and we will be purely limited to describing how things work." (i.e. there is some lowest level of physics)
- platz 7y agoYour 'limited hypothesis' can never be proved, because you can't prove things you haven't observed i.e. the proof works only up until counterexample, which by definition of unknowns, counterexamples (or a deeper understanding) would always be a possibility. Falsification is not end end-all-be-all, it's important, but it's not the only thing that matters.
- beloch 7y agoConsider the equation: 1+1=2 You don't have to understand the mathematical explanation for why this is so (one does exist) in order to have an intuition that serves you well in practically all situations. For most of us, there is no deeper understanding. It just is, and that's good enough. That doesn't necessarily mean there is no deeper understanding, but let's ignore that for now. What I was trying to get across is that basic intuitions we have about the macroscopic world that we can see and touch are often flat-out wrong on the quantum scale. Likewise, human language has developed to describe macroscopic phenomena and struggles to capture the meaning of quantum phenomena. Intuition and language are crucial parts of understanding, but we find ourselves on treacherous ground when we try to apply human language or intuition to quantum systems. The confidence that comes with intuition and mastery of language are wholly counter-productive in quantum physics. You need to constantly reexamine what you think you know in the light of both new discoveries and the math. Both are sources of continual surprise. Hence, if you think you understand quantum physics, you probably haven't given it enough thought.
- onemoresoop 7y agoYes and because we live in the macroscopic dimension we develop the intuition this way and thinking in terms of another dimension makes out heads swirl. Perhaps we’ll never build an intuition at the quantum scale, just some tools to abstract it away and get some benefits out of it.
- 8bitsrule 7y agoFeynman's diagrams (like the orbital model of the atom) were attempts to visualize a world we can't experience. Those of us who aren't deaf and blind begin to make audio-visual models of our macro world in childhood. We can agree with confidence that "that's a rock" (if not its physical properties). Even in our macro world, our models have limits. (What do radio waves 'look like' as they're emitted by different antennas? Go around buildings? We draw pictures.) But we're nearly deaf and blind to the quantum world. We have collections of indirect observations and math. Our models of it are necessarily limited by our inability to experience it directly. Those with math 'intuition' are in a better position ... but still.
- danharaj 7y ago> Feynman's diagrams (like the orbital model of the atom) were attempts to visualize a world we can't experience They are a convenient notion for defining path integrals.
- solinent 7y ago> [...] quantum physics on a deep, intuitive level, probably do not. Intuition and understanding are two different things. Our intuition behind quantum mechanics is obviously wrong--quantum mechanics doesn't even obey regular logic! Quantum logic gets rid of a rule, for example. So it's probably impossible to develop an intuitive understanding if that is your criteria. As we've progressed, we slowly just get used to new abstractions. The concept of zero, negative numbers, complex numbers, rationals, reals, they were all very non-intuitive to the people at the time but were required to understand the science of the time.
- rstuart4133 7y ago> However, we lack an intuitive understanding of why the equations work. I think the word mechanism captures what you are describing. We have a set of equations we know work, but we have absolutely no idea what underling mechanism gives rise to those equations. It's like the position ancient seafarers were in: the could use the sun and stars to navigate, but because they had no idea of the mechanism behind their movements they were happy with the idea the world was flat. It's not a good state of affairs because understanding the mechanism yields far better predictive powers than the mathematical equation describing what happens. For example, we had good equations describing rechargeable battery degradation. But until we understood the mechanism, we were just stumbling about in the dark on how to improve it.