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I was reading this answer of David Z about meaning of "Quantum" that this question came in mind:

If light is quantized (i.e. is a integer multiples of some unit $\hbar c/k$), are other kinds of energy quantized too?

I think all kinds of energy should be quantized because they can convert to each other and if one of them is quantized, all other kinds must be so. Is this correct?

If that is correct, then what is a quantum of kinetic or potential or internal energy of a body with mass $m$? E.g. is kinetic energy of a translating body ($K=\frac 12mv^2$) a integer multiples of some unit?


marked as duplicate by ACuriousMind quantum-mechanics Jul 25 '16 at 16:37

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  • 2
    $\begingroup$ The energy of a free point particle on the real line is not quantised. $\endgroup$ – gented Jul 25 '16 at 16:39
  • $\begingroup$ @ACuriousMind Sorry, but that question is talking about Hilbert space and I see Hamiltonian, etc. in your answer that I don't know what they are at all. So, how can those question and answer help me? Or, this (my) question needs some requirements that without knowing them I mustn't ask it? $\endgroup$ – lucas Jul 25 '16 at 16:45
  • $\begingroup$ That question is asking the very same question as you do, the asker there just has more prior knowledge of quantum mechanics. Any correct answer to this question that is not just "No, energy is not always discrete." would have to be just as technical. $\endgroup$ – ACuriousMind Jul 25 '16 at 17:08
  • $\begingroup$ @ACuriousMind Thanks! But you answered late and I voted to reopen this question. How can I cancel that? $\endgroup$ – lucas Jul 25 '16 at 17:11