Large Hardon Collider

[Kaylia]

I hate hate hate statistical mechanics, probably because I hate hate hate statistics. I have absolutely no idea how to work with summations anymore, because all the classes I've taken previously to this changed summations into integrals by making the displacement be infinitesimal. Things like (from our notes):

http://latex.codecogs.com/gif.latex?...28ln%20Z%29%29

where

http://latex.codecogs.com/gif.latex?...lon_%7Bi%7D%7D

Is there any site that I can go to that goes over things like this?

EDIT: And latex looks horrible using this black skin, sorry about that.

I'm not really sure here (what is ni?), but most of the time we were using series in physics stats, they were developped into a taylors series, and recombined using clever trick that I wouldn't have thought by myself.

[Eliseos]

ni is just the number of particles at the energy level of epsilon i. So the sum of just ni from i=1 to N would just be N.

[Kaylia]

What exactly is the problem here, I'm not sure I understand? Are you trying to understand what happened here in particular, or you simply wants a reference that explain how to deal with summation like this one?

If you're looking for a reference, I sincerely doubt you can find a good one. The simplification works on a case by case basis, and while I'm sure there is books that has the answer, using your mathematics intuition is probably the best way to go. I don't know any perfect methods to get through problem like this.

In this case, it's much easier to go from right to left in this equation than left to right. If you're wondering what happened, simply do d/dy(lnZ) and you will obtain the summation you had right before (the derivative takes 10 sec top). If you want to go from right to left, all you need is a very good understanding of series and find which equation match your series (because a summation = a series). It's really not obvious if they aren't giving you the simplified result, but easy to do if you know what you need to obtain.

[Eliseos]

Kind of both. I have no idea how that transformation happened, and I want to know how to handle stuff like that in general, since I'm sure I'll be seeing more of that stuff either with the time left in this class, or in a future class.

[Kaylia]

To go from the 4th to 3rd term, you simply need to applies the maths directly
http://img515.imageshack.us/img515/5849/equation.png


To go from the 3rd to 4th, the "easy" way is to use the definition of lnZ derivative, and use a substitution


The first egality is a definition, and the 2nd egalities is a simple manipulation made from ni definition.

[Eliseos]

Wow, I am an idiot lol. For some reason I thought there were some special rules with summations and derivatives of them. I guess this is why I suck at math lol. Thanks for the help, Kaylia.

[Kaylia]

oops, just realized I used "e" everywhere instead of epsilon...not that it matter much

Wow, I am an idiot lol. For some reason I thought there were some special rules with summations and derivatives of them. I guess this is why I suck at math lol. Thanks for the help, Kaylia.

That's what physics is all about, facepalming yourself at how easy it is after wasting many long hours. It never makes you feel smart, you go from "why can't I understand this?" to "why couldnt I understand this earlier?"


I guess I should have said this first, but whenever there is a notation you're not familiar with, turning it in its simplest form often give you big hints. It's particularly true in quantum mechanics where every single variables hide a zoo of mathematicals entities.

[Eliseos]

Yeah, I didn't even think about expanding the sum, would have made that problem much much easier lol.

In other news, Stephen Colbert was apparently offered astronaut training thanks to his show throwing some light on Obama cutting out the Constellation program, and then him changing his mind and now supporting it (Obama).

http://www.colbertnation.com/full-ep...-aimee-mullins

EDIT: It's the first part of this episode.

[Max™]

No one has even answered my questions about how they think our brains produce our minds/experience/thoughts. They wanted to argue about psychic powers instead

I did, sorta, but I was merely suggesting that while I could rationally consider a suggestion that there was some quantum bullshit involved with awareness, I can't do the same for a suggestion that there is something which has completely eluded every attempt to detect a mechanism for it.

Shit like this: http://www.cosmosmagazine.com/news/3...cts?page=0%2C0

Makes me wonder about shit like this: http://en.wikipedia.org/wiki/Quantum_mind

Which, unlike psychic crap, can be tested, and is at least based on a known aspect of reality, that being quantum effects.

[Pirian]

lol

"Based on past experience, I predict this work will be misrepresented ..."

Can anyone find the irony in me posting this quote from that article?

[Kryssan]

The hell is going on here? You should all be ashamed of yourself for arguing with him for a page and a half. You should have just given him the and moved on to a new topic after just a few posts. That crap doesn't belong in this thread.

Hey hey. I'm still trying to recover from turning into a wereskag every time someone uses the words cold and fusion in the same sentence. Especially now since more data and research has been conducted that might even suggest that its more than a hoax (referring to SPAWAR's [I still pronounce it spa-war too, damn them, who names something spay? Bad neuter joke waiting to happen oooooh wait...] conclusions from '09). Gotta start giving 'em a chance to garner some proof before the . Of course, after the first post regarding 'sources' (to which I was in bed for at time of posting, but meh), the was warranted.

[Psion]

Gimmie a break, I'm not a scientist, and my google skills suck, and also I'm too lazy to spend weeks gathering the most credible and scientific sources before posting Also, some of those scientific journals require membership (aka money) to view their reports and such, which I certainly don't have atm.

And considering how controversial the topic is, and the bad starts and rep that it gets, it's pretty hard to locate the cream of the crop for someone like me. ;;

(Thanks for that info though, haven't heard of that experiment. Something else to read about)

[Woozie]

Hey hey. I'm still trying to recover from turning into a wereskag every time someone uses the words cold and fusion in the same sentence. Especially now since more data and research has been conducted that might even suggest that its more than a hoax (referring to SPAWAR's [I still pronounce it spa-war too, damn them, who names something spay? Bad neuter joke waiting to happen oooooh wait...] conclusions from '09). Gotta start giving 'em a chance to garner some proof before the . Of course, after the first post regarding 'sources' (to which I was in bed for at time of posting, but meh), the was warranted.

Well, I understand giving him a chance to explain or post evidence, but there's no reason the discussion should have went a page and a half without a credible and respected peer-reviewed journal article cited.

And Psion, you're right that even if what you're saying was correct, it would be hard to find an article. But nonetheless, we can't consider it appropriate for this particular thread until such evidence is posted. Especially since we're all skeptical of this subject (and you probably knew we'd be skeptical even before you posted. You admitted yourself the subject is controversial).

[Psion]

Hey hey. I'm still trying to recover from turning into a wereskag every time someone uses the words cold and fusion in the same sentence. Especially now since more data and research has been conducted that might even suggest that its more than a hoax (referring to SPAWAR's [I still pronounce it spa-war too, damn them, who names something spay? Bad neuter joke waiting to happen oooooh wait...] conclusions from '09). Gotta start giving 'em a chance to garner some proof before the . Of course, after the first post regarding 'sources' (to which I was in bed for at time of posting, but meh), the was warranted.

Mind posting the article or link about SPAWAR's findings? I can't find it, but then again my search skills are atrocious. ><

::Edit:: And every time I search for anything related to psi and find articles talking about the pressure per square inch version I wanna kill someone.

::Edit 2:: I think I found a livescience article on it, does this sound right?
http://www.livescience.com/technolog...ld-fusion.html

Would be pretty cool if it works and is able to be put to practical use. Though I do remember popular science talking about a "star jet", basically using the extreme heat of fusion to break down garbage into its elemental particles, essentially becoming the ultimate in recycling. Do you think if cold fusion works, would this star jet ultimate incinerator idea work with it? Or is it possible with any fusion reaction for that matter, without shutting the whole chain reaction down?

Also, would cold fusion being real change the way scientists view physics and/or prove or disprove certain theories?

[Kaylia]

Gimmie a break, I'm not a scientist, and my google skills suck, and also I'm too lazy to spend weeks gathering the most credible and scientific sources before posting Also, some of those scientific journals require membership (aka money) to view their reports and such, which I certainly don't have atm.

It's not your google skill or anything, none of the research in that domains are ever going to be addressed at the scientific community. They are addressed at people who are interested in fringe science, and have little knowledge in the field of mathematics and physics.

Ganzfeld is the only "serious" (in appearance) experiments that took place, but considering the result, the lack of follow up speak for itself. Imagine that you found with certitude that human could in fact communicate with telepathy...don't you think you would push your experiment a bit farther? That's a fucking breakthrough in every possible domain, and would change completely our way of thinking? So why is it staying in the dark?

I can't deny their result ( all contained within statistical fluke), but there is something incredibly fishy about these. Something so fishy that make me willing to bet a lot of money that if I was doing the same experiments, I wouldn't obtain the same result.

[Max™]

Incidentally, Cold Fusion being real would be really handy, but it wouldn't require a really drastic change in our models of physics that I can think of... it would be a case of fleshing them out in a particular area.

I remain skeptical on that as well, though.

[Mizango]

Cold fusion via Hawking radiation?

[Isla]

Not to be confused with the Large Hardon Collider!

[Mizango]

*We were colliding logs in here a few weeks ago apparently. But balls did not touch so it was ok.... or so I heard.


*Generalization

[Eliseos]

But balls did not touch so it was ok

Says you.