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02:35
have any of you read The MANIAC by Labatut?
It is a semi-fictional semi-biographical book centering around von Neumann
I am confused by the fact that (1) textbook QFT is all over "particles". fundamental fields transform under irreps of the poincare group and (2) "particles" *cease to be well-defined* when you talk about an interacting QFT!

Am I misunderstanding or misrepresenting the situation? I don't understand why people are not concerned with this state of QFT.
02:54
how curious. in bargmann's expository paper of Wigner's theorem, there is an appendix on Wigner's theorem in quaternionic quantum theory.
03:17
has anyone ever seen greek symbols used for such purposes :P
03:30
@SillyGoose the beta prime gets me lol
oh my god
Do ya'll know angela collier
@SillyGoose i think you're talking at a higher level (and certainly over mine) but just curious have you read "There are no particles, there are only fields"?
I watched her video on Feynman bros
So so strange I never noticed that LOL
@Allie what's her take?
That theyre often weird and condescending and there
is a weird mythology surrounding Feynman
03:36
not a novel take to me xD
Well i'm not a physicist
I'm in chemistry :)
I'm sure it's been said many times over but that was my first time running into it
I didn't even know Feynman bros existed but it reeks of the same brainworm that infects crypto bros
and AI bros
 
2 hours later…
05:23
@Allie that's her only video miao miao watched, but she is very correct.
meow
05:39
I feel it's not a one-off phenomenon.
We plausibly have another user who is resorting to gen ai.
The traits are similar:
in Ten fold, 12 hours ago, by User1865345
Generally I have noted they hardly comment and answer pretty rapidly.
in Ten fold, 9 hours ago, by User1865345
Another general trait of such users is they target three more communities, at least, other than CV: Maths, MO, Physics.
Already the said user is banned at MO.
Might be wrong, but of late, these users follow the same rule book and pose as jack of all fields (physics, maths, stat/machine learning). They hardly respond to comment; answer multiple times a day in a somewhat mathgen like structure.
 
2 hours later…
07:47
hi
 
2 hours later…
09:26
@User1865345 Please raise custom moderator flags on posts you suspect to be computer-generated
@SillyGoose I'm not sure what you mean by people being "not concerned" about this - every textbook account of QFT spends a bunch of time defining the asymptotic particle states in terms of the asymptotic "free" fields to derive the LSZ formula. It's well-known that the full state space of an interacting relativistic QFT is a messy object, but it's just a hard problem.
But for the prime application of relativistic QFT - the computation of scattering amplitudes or more generally n-point functions - it doesn't matter much (if at all).
@qwerty There are various workstreams you might look for - "constructive QFT" in the vein of the functional integrals of Glimm and Jaffe although I don't know of a lot of progress after their initial work there, algebraic QFT in the vein of Haag and Kastler or the more analytic approaches like Epstein-Glaser renormalization or Streater's and Wightman's Spin, Statistics and all that. I'm not really up to date on current work.
09:42
@ACuriousMind thanks! this is very interesting.
Why exactly is parallel transfer called parallel transfer? How does one show that the vector is actually parallel?
For all affinities
The name is because of how the operation of parallel transport can be phrased in terms of a projection to the vectors parallel to the manifold if you embed it isometrically in $\mathbb{R}^n$, see e.g. mathoverflow.net/a/387538/157071
10:01
@ACuriousMind this link is about the Levi Civita connection. it is worth asking whether @DIRAC1930 wants to know about parallel transport in general or the Levi Civita connection
@SillyGoose You've asked about this stuff before, eg
Nov 1 at 12:47, by Silly Goose
I do not understand what Schwartz is trying to say in this section. (My understanding): The end result that is wanted is some operator that relates the free to interacting vacuum. I am not understanding the logic that Schwartz comes to the result.
I was wondering about the case of having a general connection
It's like those ancient maps that have sections labelled "Here be Dragons". ;)
38
Q: Can virtual particles be thought of as off-shell Fourier components of a field?

knzhouI just found this blog post, which gives an interpretation of virtual particles I haven't seen before. Consider a 1D system of springs and masses, where the springs are slightly nonlinear. A "real particle" is a regular $\cos(kx-\omega t)$ wavepacket moving through the line, where $\omega$ satis...

@PM2Ring lol it would be fun to add "here be dragons" labelled to certain topics, to those maps-of-physics people have made (like this one) historyofinformation.com/detail.php?id=5070
10:16
@DIRAC1930 there it's just habit - we use the same name because the formulae are the same, not because you could reduce it to any notion of "parallel" in terms of the Euclidean embedding; it's still a projection in terms of the Ehresmann formulation of a connection (i.e. as a horizontal/vertical split of the tangent space of the tangent bundle) but this does not directly relate to the embedding
@qwerty Nice map! Pity that some of the text is too blurry to read.
Ok thanks
@qwerty Yep. Much better.
@DIRAC1930 also see these answers physics.stackexchange.com/q/212167
10:21
Thanks
note that the Christoffel symbols define the notion of parallelism between different tangent spaces. so u can take it as the definition of "parallel"
the answers explain it well
@RyderRude >I find it more helpful to think of gravity as simply arising from this need to correct for how the underlying spacetime forces us to use different basis vectors at different points. In relativity theory, the physical counterpart of 'change of basis' is change of state of motion.
unique way to express it. seems nice
@qwerty i think the metric is also an important part of GR. It can't be reduced to the connection
but there r formulations which don't use the metric
they replace it with "frame fields" and stuff
which is sort of like the connection
but i haven't studied them
i think the metric is an observable. so one should keep it. it can be measured by measurement devices
in canonical GR, they keep the time but may replace space with other stuff that is like the connection
but they still have to re-introduce area and volume observables
@RyderRude uhm I wouldn't say that exactly. But I am particular with with what I call "observables".
@qwerty what is ur idea of observables
10:34
@RyderRude is it this?
@RyderRude or is it this? claiming contradictory things is just so you by now
@naturallyInconsistent it is not contradictory
maybe, if you are unsure about something, choose to not comment, or not phrase things so definitively
in canonical GR, they keep the time and replace the space with frame fields
in some versions of canonical GR
Like LQG
you are merely laying bare that you dont understand what it is you are looking at
in the Palatini formalism, they vary both connection and metric independently
@naturallyInconsistent it is in the LQG lectures
10:38
@RyderRude did I ever claim otherwise?
@qwerty I explain the relation between the metric and the phrasing in terms of a spin connection and a vielbein frame in this answer of mine
see this @naturallyInconsistent
@RyderRude no i am not going to.
@RyderRude "loop quantum gravity" is certainly not the same as (or a subset of) "canonical general relativity". I would suggest you take knowledge more seriously.
@ACuriousMind it is related to it
i shouldn't have said "like LQG"
i meant the Ashtekar variables formalism
which is purely classical
@naturallyInconsistent see this en.wikipedia.org/wiki/Ashtekar_variables
10:46
@RyderRude STOP TAGGING ME. I am much more familiar with it than you are.
@ACuriousMind I have so much to learn.
@qwerty but all at your pace, no pressure to actually finish learning them all
gtg bye
@naturallyInconsistent ciao ciao miao miao~
omg the chat escalates sometimes
@User1865345 it's a plague :/
11:12
@Allie YouTube just recommended me a Video of her haha
@Allie very relatable content for my jaded millennial soul and the only one I know making video essays in that style on physics-related topics
11:28
@Allie i have been to her channel
 
1 hour later…
12:48
@Allie I find it quite eerie that YouTube has recommended me a video of her today after you've mentioned her in the chat lol,I feel like YouTube is secretly watching what I'm doing on the internet :p
I happened to watch a video of her on why the famous billionaires all seem to talk about physics and have considered taking up physics in college. I should say it's eye opening
@TobiasFünke what books you recommend for a beginner who has studied some quantum mechanics and wants to start studying condensed matter physics,I would prefer if the exposition were clear and uncompromising when it comes to detail and rigor.
"I would prefer if the exposition were clear and uncompromising when it comes to detail and rigor."-- I did not find any such book lol
@Arjun condensed matter is huge. what do you want to learn exactly?
Nov 9 at 14:03, by Tobias Fünke
Altland and Simon (Condensed Matter Field Theory). Chaikin and Lubensky (Principles of condensed matter physics), but this one I only skimmed through for some certain chapters. The books by Nozières and/or Pines are classic. A solid solid state book is Grosso Parravicini, and I think Ashcroft Mermin is fine too and covers many topics.
@TobiasFünke Hi, i actually have a course in cm the upcoming semester(starting in jan) and it's the first ug course in cm,I have looked at it and to me it looks like solid state physics predominantly
Ok. Standard book is still Ashcroft Mermin
@Arjun I normally avoid videos on science/physics (I prefer anything written, as I find it tends to be more precise and be writing for a less general audience) but that sounds intriguing...
Ziman is fine, too
13:10
@qwerty Hi,Even I don't watch videos on science that often since I find them to over simplify stuff to reach a greater audience and sometimes exaggerate some points to go viral,but this person seems to be sensible(atleast as of now lol),I'm planning to watch her feynman video after I study some actual physics for the day : )
@Arjun yeah I'm watching now, seems like she's not talking down or being clickbaity! I appreciate that. in incognito mode though, so that I don't get recommended more unless I search for it 😅
@TobiasFünke the above pic has the syllabus in case you care..
@qwerty xD I just turn down the search history for my main account so that it stops showing me recommendations
Her best video is of course the 4 hour complaint about Star Trek: Picard but I guess that's for a more specific audience ;P
@ACuriousMind I think that's one of her highest viewed videos :p
@ACuriousMind ohhhh I've got to share that with my partner lol
13:17
@Arjun yeah, then Ashcroft Mermin, Ziman, and Chaikin and Lubensky should be fine
@TobiasFünke Thanks
welcome, no problem
The upcoming sem is gon be quite heavy lol ,I'd be juggling statistical mechanics,electromangentism and str,solid state physics,quantum mechanics-2,quantum information theory and Topology :')
I'm sh#t scared
@Arjun huh, so it is - I guess media criticism is more accessible to more people than the other topics
"bro, you have a billion dollars. you could just [hire live-in physicists to teach you physics and be on papers]" lol
13:21
@qwerty That's one of my favourite lines from that video lmao
All my friends wish constantly to be in that position lol
i dont know how many physicists would wanna be associated/co-authors with elon musk now though. I guess you'd have to be compensated pretty sweetly.
@qwerty co-authors? I think bro's pretty far away from that point lmao
@Arjun I mean, her point was if these billionaires really want, they could pay to be taught physics and be on research projects. people get credit on papers for even small tasks.
@ACuriousMind After all star trek is more popular than brian greene & co. I guess? :P
@ACuriousMind 👍🏻
@TobiasFünke of course and it's definitely frustrating.
13:30
@qwerty Oh boy I forgot these people are literally the best for making others do the work and get more credit than they ever deserved :') ,so yeah they can very well get published
@Arjun this is her latest video, isn't it? Well, even that came in my feed and I don't watch physics religiously.
@User1865345 Hmm so someone on the chat works for YouTube
🤣
@qwerty One should better make their cats as co-author than Elon.
@Arjun I know professors who barely did anything and got their names on papers their students or postdocs wrote... it's not right, but the juniors sometimes don't mind if it's a bigger name attached...
@User1865345 Lmao
13:35
@User1865345 That's already been done: en.wikipedia.org/wiki/F._D._C._Willard#
What? 🤯
@User1865345 oh lol I thought that's what you were referencing already
@qwerty Interesting..As long as the juniors don't mind I think it's ok,maybe.But I wonder if some profs do it regardless of what their students think
@qwerty hm. That's actually true and it's prevalent in academia.
@Arjun correct. it's unethical.
13:37
@Arjun Welcome to the wonderful world of academic misconduct!
@naturallyInconsistent is that you lol? en.wikipedia.org/wiki/F._D._C._Willard#
I have written scripts for one of my profs, only to see there are others who never contributed in the first place.
@ACuriousMind I thought they only fudge the results sometimes(ofc this even is un-acceptable) but stealing your student's results is downright evil
@Arjun once you enter your second year of masters, you would know what this is all about.
@User1865345 Please don't jinx lol
13:43
😅
@Arjun ...I regret to inform you that there's plenty of evil in the world
Hmm
For now, enjoy your ug years. But be aware of your surroundings and circumstances.
There is a long path to go. And it's not at all smooth.
I wonder what's the least corrupt profession with the least amount of politics playing(I used to think academia was like that,but now I see how un-informed I was..)
13:46
Next thing is to create an account at Academia.SE...
@Arjun but it sounds interesting ;)
@Arjun outside world is not black and white. Characters are grey.
it is about massive gravity, causality and quantum gravity
@User1865345 Advice noted..👍
@User1865345 lmao
@User1865345 be careful of this too though. yes, situations are complex. but rationalwiki.org/wiki/Balance_fallacy
13:50
@TobiasFünke Yupp but I'd be fried every single day though,I hope I retain my interest in physics post next sem :p
@qwerty ahh. Yes. Of course. (Lol both Carter and Trump beg for money -- good one).
i just share my ideas, not worrying about credit cuz they probably won't get noticed anyway even if they r correct
i have shared some research-ish ideas on PSE
@RyderRude I think it's imperative not everyone has to respond to every message irrespective of the veracity of the same.
@RyderRude since any more subtle criticism seems to have fallen on deaf ears: Stop posting these clickbait videos here.
If someone wishes to initiate a discussion, perhaps they would. 😅
13:54
@User1865345 what do u mean
@ACuriousMind it is a podcast with an established physicist. the title should be irrelevant...
It is a podcast with Claudia De Rham
What I meant is if anyone wants to discuss anything, they would. If you wish, you may post something but it is another thing to expect that would warrant a response (without additional context).
@User1865345 oh. i agree
@Arjun wow. Even without any idea, I must say there should be some heavy lifting involved. Good job if you can. Best wishes.
i sometimes see an expert talk and strongly feel that they miss some basic ideas
We also do study information geometry and it's a growing field. Although my current research area doesn't fall under it technically, I feel it could be relevant and so I have ventured there.
13:59
but maybe it is because they don't go into detail
but it is a strong feeling
maybe everyone overlooks something
i have sometimes seen experts being corrected by other experts. so it is not an incorrect feeling
@User1865345 Thanks for the wishes..🤗
e.g. i was watching Carroll once and he said classical mech is non linear while QM is linear. i knew it was incorrect
and he immediately got corrected by someone else
so i think it is possible for experts to overlook basic ideas
i was watching Claudia's podcast and she has an extremely contrived view of causality
but she didn't get corrected
she says formulating causality requires dealing with infinite frequencies
Maybe it's not that he didn't knew(could happen though). But I think he was under immense pressure to make complex stuff understandable to his lay audience and lost on crucial details in the process
@Arjun it was actually a physicist meet-up. the audience were physicists
Carroll ended up correcting himself a bit, but the revised statement still feels incorrect to me
it should be in the second half of this debate
@Arjun i think that experts expertise in some narrow field and they may overlook other things
an honest question: why do you watch so many "debates"/podcasts? :d aren't these usually intended for a more or less lay audience?
14:11
Once again, it would behoove you to be more serious about knowledge: There is an obvious sense in which the statement is true: Sums of solutions to the Schrödinger equation are again solutions (=QM is linear) while the corresponding statement is not true for all classical equations of motion (=CM is non-linear). Now, it might be that in the given context that's not really relevant, but to act as if this is an obviously false statement is just misleading.
@User1865345 information geometry sounds really interesting
@ACuriousMind i know that ofc. what I mean is that the Heisenberg equations are just as non linear as the classical equations
I wouldn't be surprised to find "wrong" statements. The point is that statements about math or physics mean "nothing" without a crystal clear definition of what exactly is meant, and this more often than not requires background knowledge, which most people definitely not have
2
we should compare apples to apples
@ACuriousMind Carrol made that point as the reason why QM was superior to CM. But he had to correct himself becuz of the same reason i gave
@TobiasFünke it's good those hand wavey things are lesser in statistics community. I haven't found that staggering number of books written for lay people in stat/machine learning than that in physics.
sure, because I guess it sells better :P
14:14
@TobiasFünke i find them thought provoking..
universe, black holes, worm holes, time travel, quantum jumps...all those buzzwords
@TobiasFünke correct. Physics is more alluring.
@RyderRude The Heisenberg equation of motion is also linear in this sense - time evolution is also a linear map on operators.
@RyderRude fine; but as I said: you should not be surprised that some statements are shorten, need context etc.
@ACuriousMind but that wasn't what Carroll had in mind. as I said, he did correct himself because of the same reason i gave
14:16
If you wanted to show off how much smarter you are than an expert, you should have chosen the example more carefully (which given that you had infinite time just not to say something is an unforced error).
If you want to criticize them, read a corresponding paper and either write a response or a new article in a journal, for example.
@TobiasFünke stat buzz words like regression, minimax, bayesian, likelihood... Nah they don't sound cool.
@ACuriousMind please don't misquoted me. i have only said that anyone can overlook basic things
@User1865345 indeed :d but there are some books for a wider audience, discussing the basics of probability, statistics etc. a famous example is with testing in e.g. medicine and conditional probabilities (Bayes theorem)
@TobiasFünke i am not criticising. it is natural to overlook some things...
@TobiasFünke also, i understand that they generally understand physics much better than me
14:18
@RyderRude you miss my point. I say that you should not take a single statement in a podcast as a scientific statement
@TobiasFünke there is, especially for audiences who have gotten proper statistical education. But since machine learning is in the market, people tend to sell easy paths especially for branches like clinical trials, epidemiology and the applied field altogether.
@TobiasFünke yeah...maybe it was meant as a non serious statement,
it is a difference if I talk 2h to lay people and explain physics in a very oversimplified manner, or if I write a scientific paper/report/book/text for an audience which understands the physics/math
2
@TobiasFünke true not only for physics but for any topic.
do any of you personally feel uncomfortable to oversimplify things, and hence completely avoid talking about physics to non maths/phys people?
14:21
and my point is that if you want to criticize or whatever, you should target the latter form of "communication".
@TobiasFünke i don't mean to be critical. but it is possible that an expert can overlook some basic ideas.
especially ideas in a field they don't do research in @TobiasFünke
@User1865345 since that sinking of that billionaire's boat... 👀
@qwerty at least I am not advocating that if you understand this thing, you can explain it to a six year old. Nah, man. This ain't possible.
it is only human
@qwerty yes, most often. it depends, though. some friends majored in cs or engineering, so they also have a much better understanding of e.g. math or basic physics than most others
14:22
@qwerty 😅🤣
@RyderRude my last respond: You miss my point! If they "overlooked" something, then go to their papers/texts/books whatever. Everything else has no real scientific value, roughly speaking
@qwerty i don't feel uncomfortable... some ideas are non-mathematical. u can communicate those
@TobiasFünke i will take this into account now.
@qwerty but many non-physicists are interested in things like black holes, expanding universe etc., where I also have no real knowledge, and hence I avoid these discussions haha
glad I'm not alone. although, I think, the more deeply you understand something the better your chances of explaining something clearly and simply. as Ive said before, I think to teach a subject it's kinda feels necessary to me to know it two levels deeper. although I think not everyone agrees.
@qwerty yes, I'd agree in general
also in teaching you have to cut down things, no?
14:27
yeah that's right
When doing a QM course, you normally would not start with functional analysis
@qwerty no, I don't avoid it but don't seek it out, either, since I don't enjoy going "it's more complicated than that" to every pop-sci misconception they've soaked up :P
so you oversimplify
@qwerty I am still not sure why that rich guy named it bayesian. After all, bayesian techniques are used so much everywhere that it's not special anymore. But maybe he felt deep connection.
@ACuriousMind haha, that is my standard reply
But how much you simplify, leave out etc., of course depends on the audience
14:28
lies to children all the way down
but I wonder how many people you know that want to discuss about physics and so on :D does not happen on a daily basis to me
well, my extended family asks about work sometimes, and I clam up :p
back when work was physics
i have tried explaining equivalence principle by making things fall
quantum correlations too
@TobiasFünke Usually I'm at a party and someone goes "I watched a documentary about black holes/string theory/whatever last night" and then says something so wrong as a summary I can't help but correct them :P but it happens like once every 2 months or so
14:32
i had to correct someone about mass energy conversion
@TobiasFünke I had hard time teaching a non parametric course to a group of psychology graduates. I can dilute something at the expense of sacrificing many results which I am not at all happy about. But had to. Definitely not going to do for lay people.
but I know feel they were more correct than me
As I said, my knowledge in e.g. GR (or even SR) is not good enough that I would like to start a discussion, i.e. I don't feel confident enough even though I might have the answer to some specific questions, or could correct some misunderstanding
they said something like "things at rest have mass which gets converted to energy when they explode"
I also feel kind of stupid every time I read the chat haha. reminds me only on all the things I don't know
14:35
i told them that energy was the same thing as mass
so mass couldn't be converted into energy
but I think they had some point
@User1865345 what do you mean with "non parametric course"?
@TobiasFünke non parametric statistics. These are bunch of tools you need when you don't have the usual parametric assumptions.
@qwerty ah, well, for small talk I usually just pick the basic kind of physics I expect them to be familiar with (xkcd) and go "like that", e.g. gauge theory is about more complicated cases of being able to add constants to potentials
See? I diluted so much that I risked oversimplifying the field.
14:37
xD
@TobiasFünke you have to work with rank, symmetry of the cdf and additional smoothness conditions.
it happens everywhere
@User1865345 do u use manifolds in information geometry
Social science students only need advice when to use which tool and other subsequent wisdom. After all they will only use R Or Stata to run a code and voila.
@RyderRude yes
14:39
interesting
what do the points on the manifold represent
In information geometry, the Fisher information metric is a particular Riemannian metric which can be defined on a smooth statistical manifold, i.e., a smooth manifold whose points are probability measures defined on a common probability space. It can be used to calculate the informational difference between measurements. The metric is interesting in several aspects. By Chentsov’s theorem, the Fisher information metric on statistical models is the only Riemannian metric (up to rescaling) that is invariant under sufficient statistics. It can also be understood to be the infinitesimal form of the...
@qwerty lol i know. It’s like vector…tensor…vector. About your other comment: i haven’t seen that paper but I’ll take a lookzie now. Thank you for the reference
Whenever I discuss with students, I try to at least in one or two sentences, point out that the situation is, actually and as so often, more complicated, and either refer to literature or say we'll discuss this later
But I cannot just start, this test is for that without discussing how the test is developed.
@TobiasFünke good.
@User1865345 I feel you
14:41
@ACuriousMind but what i mean is that the textbooks only care about (dubious choice of the word carefully) defining the LSZ reduction formula and then explaining how to compute it conveniently.
@User1865345 it seems like physics systems can have analogies in statistics systems
Maldacena said that gauge theory has exact analogies in economics
these analogies would be interesting to learn
@RyderRude I think Jakob Schwichtenberg has a book about this
@TobiasFünke i will check it out
"Physics from Finance: A gentle introduction to gauge theories, fundamental interactions and fiber bundles"
@SillyGoose yes, because that's what the main purpose of hep-th intro to QFT textbooks is. I'm not sure what exactly the complaint is :P
14:44
but I haven't read
@ACuriousMind has anyone ever watched a documentary on diffeomorphism invariance :)
@TobiasFünke yes. That's what I found
@TobiasFünke i will read it. analogies r helpful
@ACuriousMind Any idea why the nlab claims that flat connections are the connections lifted from $B\sharp G$
@ACuriousMind but i guess i don’t get this. Not everyone is going to work for CERN or etc. isn’t there some need for a less computational book on qft?
@SillyGoose whenever I am in Heidelberg I will tell everyone I watched one. Then I will attract ACMs attention and get a free lecture
14:45
They never explain it too well
@TobiasFünke lol
Jakob Schwitchenberg would've had to expertise in both physics and finance to write this book
@SillyGoose sure, but that's not what the intro books are
pretty crazy
Actually $\flat BG$
14:48
@RyderRude I don't know how much "finance" there is in the book, except possibly some analogies.
I've already referred you to e. g. Reed and Simon for a more formal account of the scattering theory setup, but beyond that I'm afraid it's mostly monographs and papers, not textbooks
Economics just seems like math :P. From my small experience in an introductory course, the content is nothing you wouldn’t expect and the nomenclature is absolutely horrible.
@TobiasFünke i think it would have to be at least a third of the book, given the title
some physicists often switch to finance
there is a field called physics finance or something like that
there is econophysics
cool name
14:50
and related to that sociophysics or so
but these are subfields of physics (and other subjects)
Idk if you mean this
Hm but i think i don’t want to know more about scattering theory, i am more interested in gaining some glimpses into the interacting Hilbert space and time evolution proper. I recall that r&s discuss a rigorous way to relate asymptotic to interacting hilbert space.
There isn't really just an "advanced QFT" book except perhaps the second volume of Weinberg, there's instead dozens of different aspects you can be interested in that each have different kinds of literature
i meant using physics models to model finance or economics @TobiasFünke
like a model that is mathematically equivalent to electromagnetism but its interpretation is economics
Maldacena talked about these models
@RyderRude You can work for ren tech and tell us their secret algorithm
@RyderRude are you talking about a certain pde common in both fields?
14:53
@SillyGoose :) it's probably not actually not quite what you were talking about, but tangentially I thought it was quite a nice generalist/lower level article
@User1865345 for electromagnetism, i think the equivalence of pdes would be sufficient
@User1865345 but in general, one can carry over other physics techniques too
Maldacena talked about gauge theories in economics if I recall correctly
Ergodic theory is used in statistics, if that is what you want.
@SillyGoose they do, and they also discuss asymptotic completeness (that the two spaces are equal) as a property realistic QFTs are expected to have, i.e. you can express everything in terms of free particle states.
@User1865345 oh
@User1865345 it seems to use phase space and group theory techniques
@SillyGoose they might be using a lot of brute force computation these days
Veritasium made a video about this
a mathematician had a secret algorithm back in the 70s but it was leaked in the 90s
and the hedge funds would have improved a lot on that by now
We do use invariant measures a lot for invariant testing procedures.
Group theory applications are immense.
15:01
@User1865345 oh
@User1865345 what do you think about the viewpoint "lies, damned lies, and statistics"
Absolutely true.
There are literally tons of bogus papers who resort to p hacking and manipulate their results.
Statistics is not a machine which provides a clear cut output.
Without going to the argument whether assumptions have been assessed beforehand, the final result can be deceptive for inferential purpose. A single p value, for example, doesn't really say much, unlike what is taught in many places.
i think multiple independent studies should report the p value
I cannot explain everything here. But there are very good posts at CV explaining these.
APA decided to ban the reporting of p values altogether.
15:07
wow
This was the official article.
NHST is flawed. Yet these techniques have not been phased out.
Not that it is possible.
"perfect is the enemy of good"
@RyderRude read about meta analysis.
Meta-analysis is a method of synthesis of quantitative data from multiple independent studies addressing a common research question. An important part of this method involves computing a combined effect size across all of the studies. As such, this statistical approach involves extracting effect sizes and variance measures from various studies. By combining these effect sizes the statistical power is improved and can resolve uncertainties or discrepancies found in individual studies. Meta-analyses are integral in supporting research grant proposals, shaping treatment guidelines, and influencing...
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Q: ASA discusses limitations of $p$-values - what are the alternatives?

TimWe already have multiple threads tagged as p-values that reveal lots of misunderstandings about them. Ten months ago we had a thread about psychological journal that "banned" $p$-values, now American Statistical Association (2016) says that with our analysis we "should not end with the calculatio...

That would be a good start.
Check the tag for more threads.
15:34
@User1865345 thanks. i will check it out
 
2 hours later…
17:15
@Arjun sadly, not anywhere near as majestically cute.
17:31
@TobiasFünke @arjun there is a strict simplification and strict subset of A&M by a Steven Simon, but you'll find it easier by googling oxford solid state basics. The utility is that, because it is shorter, you can quicker finish the book and move onto something that goes into modern maths version of the same. Of course, it would not be covering as much as A&M covers.
18:06
have any of you read dewitt's volumes on QFT
oh weinberg II has a section on goldstone bosons
@naturallyInconsistent I know these lecture notes, yeah these are quite good, IIRC. What do you mean with "modern math versions"? Can you name an example?
wow weinberg II seems quite interesting
@naturallyInconsistent Noted.Will check those notes out..👍
why is it fair to assume that the dynamical equations are local in time?
In classical electromagnetism, a simple model of a dielectric gives rise to non-local in time dynamical equations for the electromagnetic field.
 
1 hour later…
19:34
What do you mean by local in time?
That the equation is only dependent on one possible point in time?
Oh involving no time integral
it's because otherwise it breaks causality?
Is this feynman diagram valid?
you can have influences at some spacelike separated point immediatly due to this
for $\frac{\lambda}{4!}\phi^x$ field?
02:00 - 20:0021:00 - 00:00

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