@DanielSank Sadly no. I usually go to the April meeting, and I don't have a project in train that would justify the travel money.
Which is too bad, because I'd like to get out long enough to see the Spiral Jetty, which I understand re-emerged a few years ago.
'Course last year I took three students with me to Baltimore and we only got far enough from the (hideously expensive) hotel to find some good restaurants.
@FrankScience your question is not simple and there are extreme subtleties/ nuances involved in bell tests (some of what you are touching on) that can literally take years to isolate, and some aspects are still not fully isolated and are under active investigation/ research. think/ can recommend an excellent general ref/ intro/ overview is the meaning of quantum theory by baggott.
@DanielSank what do you recommend as a good ref/ overview on the subj? "measurement" is at the heart of quantum mysteries despite intense study so maybe the fault is not exactly with human understanding so to speak.
"As far as I know, the only way to show that the path integral formalism yields a unitary S-matrix is to use it to reconstruct the canonical formalism, in which unitarity is obvious"
But anyway, the point is to bring attention to questions which may be answerable by regulars on this site. Kind of like hot network questions, but more focused.
@DavidZ Some world builders are extremely hardcore and ask questions along the lines of how to use the established physics principles to make a plot or setting element work
PS: Worldbuilding is probably the reason why I am so obsessed with time travel related theoretical physics, because I have a crazy setting that depends on it
Time travel as common as flying an airplane, for all types of people
One reason I want to get the physics right is because I hate plotholes, especially time travel ones
@0celo7 comments are ephemeral, so it takes very little justification to delete them. If we have to forcibly remove an ongoing discussion because it turns nasty, people can repost the legitimate criticisms.
But honestly, in most cases, by the time we get around to deleting the comments they have served their purpose. Either they've been incorporated into the answer (or question, or another question, etc.), or the OP has read them and declined to do so.
Screenshot
About
Oneboxing is when you post a link to a supported site on SE Chat and it automatically shows extra information. An example is when you post a link to a question in Chat and it converts to the title, start of the body and author.
However, the list of supported sites is short, ...
I have to say, I don't think "here's a userscript" is ever an appropriate solution to a problem. If a user experience is broken, having the user reconfigure their computer to circumvent the brokenness is really just a form of avoiding the problem.
user54412
It takes pressure off developers to actually do what they're paid to do. And it leaves the less experienced users completely helpless.
And I'm not saying people can't do whatever they want to their systems. But the culture of "let the userscipts handle it" is one I have a problem with.
@ChrisWhite When the feature is something that has legitimately good reasons to exist in the main product and won't disrupt the average person's workflow, then I agree with you. But for features that only a few people want and/or would break things for the majority of the user base, scripts are fine IMO.
My guess is that maybe about 5 features available on StackApps would make sense to add to the SE interface, even if the designers weren't swamped with site (re)designs.
user54412
Apparently someone really doesn't like me. I've gotten 3 downvotes today, and I can't remember the last time I got any. (I don't usually step into controversial questions, or answer anything I'm not 99% sure of.)
@DavidZ I have a physics question for you...why is it so widespread the belief that the wavefunction of quantum mechanics has to be continuous? (I am asking you because you seem to be one of the people believing that)
To me, it seems a really unnecessary requirement that is not supported by any physical evidence.
Though theorems on distributions I wouldn't be able to derive
"When viewing $\delta : S\rightarrow\Bbb R$ (linear and continuous with respect to the usual semi-norms on the Schwartz-space – or similar on the space of test functions), it makes sense to say that $\delta$ is continuous. "
@vzn Thanks for the reference. In fact, I was trying to clarify concepts therefore posted that question. Bell's inequality was included in the material of TD (Travail Dirigé). After having done this series of exercises, I still don't get the idea. And I realize that there are so many concepts I haven't digest well. For example, Alice and Bob are performing experiments on a composite system $H_1\otimes H_2$, and Alice performs a measurement correspondent to $T_1\colon H_1\to H_1$ (...)
(...) What it really corresponds is that $T_1\otimes H_2$, the result of the functor $-\otimes H_2$, or noted $T_1\otimes1$.
If you are interested in the problem of measurement in QM from a mathematical perspective, I suggest you read this paper by Ozawa of 1984: http://scitation.aip.org/content/aip/journal/jmp/25/1/10.1063/1.526000
If you have some knowledge of operator algebras you would find it quite interesting
Thanks, but I was confused about Bell's inequality in spin measurement, which is finite dimensional therefore no faithful operator algebra is involved.
After skimming that paper, there is something so-called locality.
I'm not even sure how one does that in the non-perturbative formulation. I know vaguely how to renormalize, but you aren't really allowed to do that if you don't know the theory can be renormalized...
@Qmechanic SE only offers feeds for tags (and for all questions, and maybe a couple other things) per site. It would be possible to have a feed that only includes posts with a certain word, or any other arbitrary criteria, but someone would need to implement it on a separate server - basically, have some code that periodically fetches the feed of all questions, filters out whichever posts meet the criterion, and republishes that as a separate feed.
Hi guys, does the two-dimensional divergence operator have a direct analogy in the two-dimensional de-Rham complex?
Like, on a three dimensional Riemannian manifold the de-Rham complex is gradient ($\Omega^0(M)\to\Omega^1$), curl ($\Omega^1\to\Omega^2$) and divergence ($\Omega^2\to\Omega^3$), and in two dimensions it is gradient ($\Omega^0(M)\to\Omega^1$) and curl ($\Omega^1\to\Omega^2$)
@Bass Divergence is always the exterior derivative from $n-1$-forms to $n$-forms. By Hodge duality, this gives you divergence on $1$-forms, which in turn gives you divergence on vector fields.
@Bass: You always have the following: Gradient is $\Omega^0\overset{\mathrm{d}}{\to}\Omega^1$, curl is $\Omega^1\overset{\mathrm{d}}{\to}\Omega^2$ and divergence is $\Omega^1\overset{\star}{\to}\Omega^{n-1}\overset{\mathrm{d}}{\to}\Omega^n$.
You can't carry them out in a sequence like you can in 3D because you cannot take the divergence of what results from the curl, not even after taking the dual
@0celo7 Well, that strongly depends on which characters you like best, which I cannot predict. I picked female for the voice for my playthrough through all three. The most popular romance alternative is the one available to both, I would guess.
@ACuriousMind so divergence in n dimensions is like $\star\circ d\circ\star : \Omega^1\to\Omega^0$, but because $\Omega^0\simeq\Omega^n$, you just write $d\circ\star:\Omega^1\to\Omega^n$?
@Secret : I'm sorry, but you'll never get the physics right for time travel. Time is a dimension derived from motion through space. A clock "clocks up" some kind of regular cyclical motion and shows you a cumulative result called the time. You cannot move through this measure of motion, just as you cannot literally climb to a higher temperature.
Screenshot
About
Oneboxing is when you post a link to a supported site on SE Chat and it automatically shows extra information. An example is when you post a link to a question in Chat and it converts to the title, start of the body and author.
However, the list of supported sites is short, ...
