Demystifier's latest activity
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Demystifier reacted to gentzen's post in the thread Graduate Sidney Coleman's opinion on interpretation in his Dirac lecture with
Like.
pines-demon quoted from Sidney Coleman's Dirac Lecture "Quantum Mechanics in Your Face" (https://arxiv.org/abs/2011.12671) and martinbn... -
Demystifier replied to the thread Graduate Why is 0 K unattainable?.You are right. If the lowest possible energy is positive, then the factor ##e^{-\beta H}## vanishes at zero temperature even for the...
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A minor point which doesn't affect your main argument: I don't think the energy has to be zero at zero temperature, it just has to be...
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Demystifier replied to the thread Graduate Why is 0 K unattainable?.The 3rd law of thermodynamics, that zero temperature cannot be attained, cannot be derived within thermodynamics itself. For that, one...
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Demystifier replied to the thread Undergrad The equivalent concept of phase change in classical mechanics.The phase of the wave function is analogous to the Hamilton-Jacobi function ##S(x,t)## in classical mechanics. If ##S(x,t)## is a...
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Demystifier reacted to Marty4691's post in the thread Graduate Why Does the Standard Model Use Six Dimensions for Probability Calculations? with
Skeptical.
So, here's the thing. The SM uses a six dimensional mathematical space to crunch probabilities. That is, one with three space dimensions... -
Demystifier reacted to Jaime Rudas's post in the thread Graduate Did Stephen Hawking fix his numerical mistake? with
Informative.
I disagree. This text is certainly not a textbook or a peer-reviewed paper, but it can't be considered a pop science book or anything... -
Demystifier replied to the thread Undergrad Necessary conditions for the uncertainty principle.Which, by writing ##q=x##, ##p=y##, becomes the usual quantum mechanical continuity equation. So pre-quantization, at this level, is...
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Demystifier replied to the thread Undergrad Necessary conditions for the uncertainty principle.Nice question and apparent paradox, let me demystify it. To simplify the math I will work in units ##\hbar=1##, so that position and...
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Demystifier reacted to andresB's post in the thread Undergrad Necessary conditions for the uncertainty principle with Like.
In (1D) quantum mechanics we deal with wavefunctions ##\psi(x)## belonging to ##L^{2}(\mathbb{R}) ##. We then have the position and...
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Demystifier replied to the thread Undergrad Why aren't photons from a laser considered entangled?.When the intensity of the laser beam is very strong, i.e., when the average number of photons is large, then the laser beam can very...
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Demystifier reacted to PeterDonis's post in the thread Undergrad Why aren't photons from a laser considered entangled? with Like.
Wrong. What is emitted by a laser is not a bunch of photons that each have an individual quantum state. The quantum state emitted by a...
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Demystifier reacted to Herman Trivilino's post in the thread Undergrad Why is thermal energy treated differently than other kinds of energy? with Like.
Excellent answer to the OP's question. In principle it is indeed an issue of being practical. Overwhelmingly so.
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Demystifier reacted to Andrew Mason's post in the thread Undergrad Why is thermal energy treated differently than other kinds of energy? with
Agree.
All good points. But I might take a bit of an issue with the suggestion that the statistical methods are just an approximation... -
Demystifier reacted to A.T.'s post in the thread High School Internal energy and gravitation with Like.
Internal energy of the cylinder? No. Internal energy of the cylinder+earth system? Yes.