Stack Exchange releases "data dumps" of all its publicly available content roughly every three months via archive.org, and also makes that information queryable over the Internet at the Stack Exchange Data Explorer (SEDE). Over time, as new features and other bits of data are introduced to Stack ...
It would be nice to have a little browser utility. Something which would essentially render the xml data as the SE sites are rendered in a web browser.
Inspired by this question, perhaps we could collect together a bunch of scripts to convert the XML data-dump files into other formats, such as SQLite, MySQL and the likes.
To keep things consistent, some guidelines:
If something changes in the data-dump, and the old script no longer works, make...
Like 100% FF7 is defined by the only guy who runs it: collect min 1 of every item/armor/weapon/materia/, beat every boss, have all limit breaks learned
Hey guys, for someone who has just completed his classical mechanics course, what would be the mathematics material he has to study before delving into QM?
Promise me that if you ever teach a quantum mechanics course you will not waste your students' time with symmetrized/antisymmetrized wave functions and will instead just use second quantization.
Please.
@Gaurav I recommend reading the first ~100 pages of R. Shankar's quantum mechanics text book.
@gonenc Thanks a lot. I was actually looking for videos on the topic, couldn't get many good ones, and then I saw your comment. It's from MIT, it must be good.
I'd tend to steer new students away from too much wave mechanics for two reasons: 1) It's almost never motivated in a way resembling any kind of sense. 2) It's not actually as useful as the Heisenberg picture. 3) (bonus) The Heisenberg picture is *much* closer to classical mechanics.
@gonenc That depends on what the n00b already knows. If the student has used matrices for classical mechanics/electronics/signal processing/electrodynamics problems and understands what a normal mode is, then Shankar's book is easy to read.
@gonenc Yes, but it's deeper than you might think a notational device could be.
What you normally think of as "particles" in quantum mechanics are not distinguishable little balls.
They're excitations of the normal modes of a system.
As explained in my linked answer, it makes no sense at all to presume that each unit of excitation has independent identity. This is an absurd notion. Symmetrized/antisymmetrized wave functions resolve this in an incredibly convoluted way.
Second quantization deals with it by not trying to give particles independent identity in the first place. It's much simpler.
However, as soon as you go to systems with more than one particle you should completely forget about first quantization and only use second quantization.
Whether there are finite or infinite modes in the system is irrelevant.
Granted, I had a somewhat special circumstance because my graduate school lab was essentially acquired by Google, but I had several other (good) job offers as well.
@DanielSank Well, I would not say that Weyl quantization is stupid...it is an extremely important tool :-P Nevertheless, I may agree that quantization is not physically relevant, the classical limit is.
It shows that classical E&M doesn't work, motivates energy quantization, and gets you Planck's constant all at once.
Then maybe talk about photoelectric effect.
From there you've established the ground rules of quantum mechanics and what's left is to use something like double slit to get probability amplitudes.
Anyway, my point about Heisenberg is that after all the ground rules are learned, the student does as some point need to start using a dynamical framework.
I'm not sure about the definition of axiomisation being used here. I'm assuming it's the process of stating a particular principle devoid of formal proof because it is so obvious.
*Proof by reference to inaccessible literature:* The author cites a simple corollary of a theorem to be found in a privately circulated memoir of the Slovenian Philological Society, 1883.
A related favorite is "because it's obvious (if you've been doing this for three decades like me, but I'm too lazy to actually explain it to you the student for whom this is all new)".
@DanielSank I know my roomie does a lot of programming and he usually swears a lot when he has to use java, which will be the case in the university he'll visit :)
Interesting SO question on what happens when you program without thinking ( [a] you find interesting undefined behavior, [b] you don't get what you actually want, [c] you get a gold badge or two )
I observed that rand() library function when it is called just once within a loop, it almost always produces positive numbers.
for (i = 0; i < 100; i++) {
printf("%d\n", rand());
}
But when I add two rand() calls, the numbers generated now have more negative numbers.
for (i = 0; i < 100; ...
Some time in the next century or so, the last person to understand low-level concepts like how data is arranged in memory will die. Civilization as we know it will then begin its long decline, à la Foundation.
Burning books is the last thing skynet would be willing to waste time on. They'd just go about cutting communications first. They're not ISIS, you see.
Regarding the thread:
Total charge on grounded conducting plane - with electric dipole & point charge
My question is considered off topic and was put on hold. Why?
Probably it seems like "fix my homework", but:
I invested quite an effort, including a descriptive image which I created.
I as...
I observed that rand() library function when it is called just once within a loop, it almost always produces positive numbers.
for (i = 0; i < 100; i++) {
printf("%d\n", rand());
}
But when I add two rand() calls, the numbers generated now have more negative numbers.
for (i = 0; i < 100; ...
Regarding the thread:
Total charge on grounded conducting plane - with electric dipole & point charge
My question is considered off topic and was put on hold. Why?
Probably it seems like "fix my homework", but:
I invested quite an effort, including a descriptive image which I created.
I as...
