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this may be weird but i can`t find the backslash button on my laptop which is like really important in latex
and i will try to justify my assumption that if it is not normal then it too will have the uncertainties in position and momentum inversely proportional
Edit: Okay, it looks essentially correct, I don't see any outright mistakes in it, but it certainly needs to be cleaned up, and I think a short glossary or nomenclature of those Greek letters would be in order to make it an easier read.
Werner Heisenberg did not derive his famous uncertainty principle by this route, because he was grappling with the whole idea about just how reliable, concrete, or repeatable measurements could be made, i.e., limitations of physical measurements, before quantum wave mechanics was actually developed. His ideas not only lead to the development of quantum mechanics, the widespread applicability of his famous uncertainty principle is such that numerous other ways have been found to "prove" it, including the one you've posted here. Here's his original work:
The proof you've posted here could be roughly summarized as follows: "A wide frequency spectrum transforms into a narrow wavelength spectrum, and vice-versa. The product of the half-widths of both cannot be less than a certain finite quantity". This is a well-known property in Fourier Transforms, so this is a mathematical fact that doesn't have to have a physical explanation for it. It's the other way around---the mathematical reality forces physical reality to follow.
As an aside, it does bring into mind the whole industry of "long baseline astronomical interferometry", which is where the use of several telescopes in different locations, particularly radio telescopes, have their data combined to improve their angular resolution, in the same way having a larger telescope aperture optically improves angular resolution (otherwise why keep building bigger and bigger telescopes?). The interesting point being raised here is that the wave interference formation the image is well understood for optical telescopes, but much harder to explain how that works for radio astronomical telescopes. The former uses a wave model, while the latter uses a statistical model. Yet, both obey similar laws and the same Heisenberg Uncertainty Principle! This is being pointed out because his principle holds true beyond just "wave physics". A deeper underlying physics is involved here--classical mechanics or electrodynamics offers no good explanation for this.
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This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.
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From a quick scan this looks like a fine derivation for the plane wave particle. Can you derive it in the general case (any arbitrary wave function)?
I would just suggest using LaTeX directly on Brilliant, it's the easiest and best formatted option.
this may be weird but i can`t find the backslash button on my laptop which is like really important in latex
and i will try to justify my assumption that if it is not normal then it too will have the uncertainties in position and momentum inversely proportional
i`ll let you know if i find anything
Thanks (:
It hurts my eyes to try to read this. Definitely do this in LaTeX.
I think I'll redo this in LaTeX first just so that I can read it.
Edit: Oh, thanks you've got it here.
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Derivationofthequantumuncertaintyprinciplethewavefunction,Ψ,isequaltoA(e)i(kx−ϖt)(1),fromeuler,wehaveA(e)iϕ=A(cosϕ+isinϕ)(1.1),lettingkx−ϖt=ϕwehaveΨ(x,t)=cos(kx−ϖt)+isin(kx−ϖt)takingℜ(Ψ)weareleftwithΨ(x,t)=Acos(kx−ϖt)(1.2)nowwecandefinekasλ2π(1.3),whichisthewavenumberand,fromeinstein,wehaveE=hβ(1.4),wherecisthespeedoflight,β=λcandhisplanck‘sconstant.themomentumofaparticle,mv,canbeextendedtomasslessparticles(i.e.photons)byrelativityE2=(mc2)2+(pc)2(seerelativitypaper)sincem=0E=pchβ=pcβc=hporp=chβ(1.5)⇒λ=ph(1.5‘)andfinallyweletϖ=2πβ(1.6)whichistheangularfrequencysubstituting(1.6)and(1.3)into(1.2)wegetΨ(x,t)=Acos(λ2πx−2πβt)Ψ(x,t)=Acos(c2πβx−c2πβt)Ψ(x,t)=Acos(c2πβ(x−ct)),β=hEΨ(x,t)=Acos(hc2πE(x−ct))2πh=ℏΨ(x,t)=Acosℏ1(cEx−Et),E/c=psothisequalsAcosℏ1(px−Et)letsthinkaboutthewaveformΨ,weknowbyfourier‘stransformsthatyocanrepresentΨas∫R\g(ϖ)cos(kx−ϖt)+Φ(ϖ)sin(kx−ϖt)dxthefourierconjugateofΨwillbespreadoutbecauseΨisalocalizedwaveformtomakeitsimpler,letslookatΨ(x)Ψ(x)=\F[ξ(η)]ifwethinkofξasaprobabilitydistribution,letsmakeξequaltothenormaldistributionΛn=μne−(n−n0)2/2δn2⇒ξ(n)=Λn∫RΛndn=∫Rξ(n)dn=1(theparticlehastobesomewhere)Λnistheenvelopeof∣Ψ∣∗∣Ψ∣,ΛnistheenvelopeofΨwecanfindthecoefficientμbynormalizingΛtheformforanormalizedcoefficientisμn=σn2π1sinceξandΨarefourierconjugatesμne−(n−n0)2/(4σ2n)=∫Rμxe−(x−x0)2/4σx2cosnxdx,ifweletx0=0RHS⇒2∫0∞e−(ax)2cosγxdx=2aπe−(2ab)2soweconcludethata=σk1andn=γsubstitutingthenewvalueswehaveμn=4πσ2x,cancellingthemoutandtakingthelnofeachsideweget−(2σkk)2=−(kσx)2whichsimplifiestoσk=2σx1whichisσkσx=21k=ℏpΔxΔp=2ℏbutthisisfornormaldistributionsonlyifit‘snotanormaldistributionit‘smorethanh/4πFinalResultΔxΔp≥2ℏ
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so do you want the latex code?
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Edit: Okay, it looks essentially correct, I don't see any outright mistakes in it, but it certainly needs to be cleaned up, and I think a short glossary or nomenclature of those Greek letters would be in order to make it an easier read.
Werner Heisenberg did not derive his famous uncertainty principle by this route, because he was grappling with the whole idea about just how reliable, concrete, or repeatable measurements could be made, i.e., limitations of physical measurements, before quantum wave mechanics was actually developed. His ideas not only lead to the development of quantum mechanics, the widespread applicability of his famous uncertainty principle is such that numerous other ways have been found to "prove" it, including the one you've posted here. Here's his original work:
Heisenberg's Original Derivation of the Uncertainty Principle
The proof you've posted here could be roughly summarized as follows: "A wide frequency spectrum transforms into a narrow wavelength spectrum, and vice-versa. The product of the half-widths of both cannot be less than a certain finite quantity". This is a well-known property in Fourier Transforms, so this is a mathematical fact that doesn't have to have a physical explanation for it. It's the other way around---the mathematical reality forces physical reality to follow.
As an aside, it does bring into mind the whole industry of "long baseline astronomical interferometry", which is where the use of several telescopes in different locations, particularly radio telescopes, have their data combined to improve their angular resolution, in the same way having a larger telescope aperture optically improves angular resolution (otherwise why keep building bigger and bigger telescopes?). The interesting point being raised here is that the wave interference formation the image is well understood for optical telescopes, but much harder to explain how that works for radio astronomical telescopes. The former uses a wave model, while the latter uses a statistical model. Yet, both obey similar laws and the same Heisenberg Uncertainty Principle! This is being pointed out because his principle holds true beyond just "wave physics". A deeper underlying physics is involved here--classical mechanics or electrodynamics offers no good explanation for this.
Nice :) the derivation I have is the one for matrix
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thanks!:)