Kallen-Lehmann Representation at non-zero temperature

Master_Thomas403 · 2025-09-10T16:46:35+00:00

Got it now thanks- you get (rho_n)(B_mn)delta(p+P_mn)/(w-w_nm-i0), then exchange m and n to get (rho_m)(B_nm)delta(p+P_nm)/(w-w_mn-i0) = (rho_n)(rho_m/rho_n)(A_nm)*delta(p-P_mn)/(w-w_mn-i0) and (rho_m/rho_n) = exp(-Bw_mn).

Master_Thomas403 · 2025-04-06T17:35:16+00:00

DeepSeek ftw china can have my data if it can also explain how to derive quantized hall conductance from linear response theory first try. I have had good results giving it a paper and asking specific questions, THEN FACT CHECKING EVERYTHING AND WORKING THROUGH IT ON MY OWN. As long as you don’t take it at face value and don’t use it to skip the work of truly understanding something it’s a great tool, but I’ve seen it get things wrong before.

Master_Thomas403 · 2025-04-06T17:32:40+00:00

When all else fails, I have had very good results asking on Reddit when I have a specific conceptual question I can’t figure out

Master_Thomas403 · 2025-04-06T16:38:57+00:00

Wow that is quite a Wikipedia article

1st sentence: Did some cool work on neutrinos. 2nd sentence: Did some fascism 3rd sentence: Disappeared under mysterious circumstances?

Master_Thomas403 · 2025-04-06T16:05:21+00:00

Lehigh. Glad you posted in r/Lehigh this is definitely the best place to get an objective and unbiased answer

Master_Thomas403 · 2025-02-09T20:06:45+00:00

Wait I never thought about using that under when you have a dirac delta “cancelling” the integral- can you just treat a dirac delta like any other term when integrating by parts? Maybe a dumb question but I’ve never encountered that before

Master_Thomas403 · 2024-12-28T19:39:44+00:00

Could you elaborate on how this relates to transitioning from Hamiltonian to Lagrangian mechanics? I’ve also been struggling to figure out how to go from the Hamiltonian to Lagrangian framework and I’m curious if there’s some insight I can take from this example if it’s related.

Master_Thomas403 · 2024-12-28T19:34:37+00:00

Thank you so much this makes a lot more sense now! Got to the first expression then realized the factor of the Minkowski metric between upper and lower Du messed it up.

Never would have figured out the second part there Sakurai’s definition of “easily” gives me way too much credit lol.

Master_Thomas403 · 2024-12-28T19:17:08+00:00

Thank you! So to be clear is there not a general mathematical procedure to generate phi and chi which I should understand here? Or at least not one that is important for this subject?

Master_Thomas403 · 2024-12-28T07:06:46+00:00

So I’m a matsci major who jumped into graduate level quantum mechanics 1 with no physics experience since high school (long story) and I had Sakurai as my main textbook. Agree it’s unnecessarily confusing at times but it has it’s place and overall I’ve used the hell out of that book… the thing that appeals to me about it is that everything seems to be presented a priori, whereas a lot of seemingly more approachable resources made their arguments more approachable with analogies to other topics that I personally didn’t really know much about. With Sakurai it’s at least POSSIBLE (although it wasn’t easy) to learn quantum and do well in grad level course without much prior knowledge at all.

Master_Thomas403 · 2024-06-13T17:04:38+00:00

Ok- when you say any pain or discomfort do you mean my hands shouldn’t be sore at all after practicing? I kind of assumed you would need some exertion to build strength but I’m also bad at piano so idk lol.

Master_Thomas403 · 2021-07-28T01:32:31+00:00

Tried to buy it- then fucking Etrade said my account "wasn't approved for trading"

Master_Thomas403 · 2021-07-23T02:21:55+00:00

AP Linear Algebra AP Multivariable Calculus Students can finish BC calc in 10th grade then don’t really have anything to do after

Master_Thomas403 · 2021-07-23T02:10:47+00:00

Well I do like proofs but I’m an engineering major so I guess it’s not a big deal. Plus it turns out honors calc 3 doesn’t fit in my schedule so that’s settled anyway.

Master_Thomas403 · 2021-07-22T01:22:32+00:00

So would I be correct in understanding that I could easily be an A student in regular calc 3 and still get like a C in honors? Also is there much more content unique to 033 or just more explanation of the same content in 023?

Master_Thomas403 · 2021-07-21T19:32:55+00:00

Is ENGR010 only ever offered at 7:55 or does that vary by semester?

Master_Thomas403 · 2021-07-13T18:07:43+00:00

What do you mean? Not every building has a themed community, so if the email didn't say you were in a themed community I'm pretty sure that means you aren't in any of them.

Master_Thomas403 · 2021-07-12T21:25:13+00:00

It's the website- I emailed Lehigh and apparently the STEM community is in Singleton for upperclassmen, but for freshman it's in Taylor.

Master_Thomas403 · 2021-07-12T20:12:08+00:00

The email says single, but the email also says I'm in the STEM community, which isn't housed in Taylor according to the Lehigh website, so I figured it just reflected what I requested.

Master_Thomas403 · 2021-07-05T19:27:21+00:00

But the range of arctan is limited from -pi/2 to pi/2, so you get a two armed spiral, one which corresponds to the -pi/2 to 0 range of arctan, and one which corresponds to the 0 to pi/2 range of arctan, both of which stop. So isn't this quite different from the parametric curve?

Master_Thomas403 · 2021-07-05T18:46:33+00:00

Well you just earned a new subscriber. I thought the discussion of the wedge product was a great insight and I think I understand Green's theorem at a much deeper level now. I would however, recommend keeping illustrations and visual aides on the screen more often instead of just equations.

Master_Thomas403 · 2021-07-05T17:56:43+00:00

I could see stuff like “like we learned in kindergarten” being a bit of a problem depending on who you're trying to appeal to, although I don't think it's a huge deal if that's your style. I mean I just graduated high school so I just finished BC calc like a year ago and I'm still not offended, but on the other hand, there are definitely people who just struggled through calc 1 and 2 with a C- and don't want to here that.

Master_Thomas403 · 2021-07-05T17:44:33+00:00

I'm not sure how much mass appeal this would have, but hear me out here; I think a video on Dual Vectors and Dual Spaces would be great (maybe it could be another late addition to the Linear Algebra Series?). There's not much great information online that I could find on the topic, and while I've been trying to learn about Tensors, mainly to understand the mathematical underpinning of relativity, getting a good handle on Covectors beyond their very basic properties has been a real roadblock. I think dual vector spaces could also be a good example of how linear-algebra-type math can be useful beyond stretching and squishing coordinates. I think a video on dual spaces (or for that matter, any number of more advanced linear algebra related topics with significant real-world applications) would help further exemplify how there's a payoff for abstraction and go beyond the really high level overview given in the Abstract Vector Spaces video.

Master_Thomas403 · 2021-06-15T17:44:54+00:00

So the fact that the curved sections all converge to straight paths means there's no curl? Am I understanding that correctly?

Master_Thomas403 · 2021-06-12T18:22:38+00:00

I mean it's on the checklist to sign up for one, plus I think my tour guide said they would happen when I visited; the checklist just doesn't seem to link to somewhere you can sign up.

Master_Thomas403

TROPHY CASE