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2:42 AM
@JohnRennie What is the possibility of the watts, amps, volts and ohms formula being wrong in certain cases? Because I've been doing testing all day on my metal melter. And the real measurements I'm getting then using the formulas to find the watts with the volts and amps. The watts that the formula gives is wrong. And is impossible. My circuit can only handle 2,400 watts but my metal melter is using 3,200 watts according to the formulas.
 
3:04 AM
@bolbteppa It might be time to just move on from interacting with this user
4
 
3:28 AM
pretty quiet in recent times here...
 
4:16 AM
@bolbteppa

Did you even click on the links?

https://chat.stackexchange.com/transcript/message/51712702#51712702
https://chat.stackexchange.com/transcript/message/51712705#51712705

https://arxiv.org/pdf/1610.09619.pdf

Just read the first paragraph og the abstract^

Link 1: https://chat.stackexchange.com/transcript/message/51712702#51712702
@AaronStevens that is rude ... While I respect everyone's right to disengage ... it is rude for someone else to suggest it for them (undermining our whole conversation)
@bolbteppa

If you wanna know what I was going on about ... I think the current answer by glS explains it: https://quantumcomputing.stackexchange.com/questions/8236/does-the-copenhagen-interpretation-quasi-classical-measuring-apparatus-all

In the comment's though I specifically ask what I "suspect" ur going on about?
However before you respond to this post please respond to the above one ....
 
5:18 AM
@Slereah Here's something I was wondering about: " "the laws of Galilean relativity hold in an infinitesimal region around a freely-falling observer" ... This is consistent with Gravity in Newtonian Mechanics?
Galilean relativity means principle of relativity in Galilean Transformations
 
6:11 AM
@AaronStevens I agree with @MoreAnonymous. What he is saying is quite normal. But it is rude of someone else to in a way interject and push for something the other person may not want to do yet. And I'm sure others will agree. It is just like someone telling you you should do this, when you yourself don't want to do that thing quite yet. .... But I digress.
@MoreAnonymous Maybe using a little less attitude will help others want to help more often. But as with everyone, its all up to the person whether they want to or not.
@bolbteppa I agree with your statements 100%. ... Sometimes we have to be a little more patient, as do many with me and I do with others. Other than that, it sounds great so far! :)
 
@ScientistSmithYT usually (there are exceptions) I give reciprocate the same attitude the person gives me which is what's going on here ... But I don't have a problem with "aggressive talk" but if "aggressive talk" is the problem then I think both users should be called out (not just me)
@ScientistSmithYT if you know whats going on maybe you can answer this?

https://quantumcomputing.stackexchange.com/questions/8236/does-the-copenhagen-interpretation-quasi-classical-measuring-apparatus-all
 
@MoreAnonymous This is one of those times we have to center ourselves. Making it so we don't mimic the other persons demeanor. Giving them the better experience, which will help the other person into wanting to mimic your good traits. This is part of the reason why I'm talking to you 3.
@MoreAnonymous I learned this real quick though. Because someone else had this conversation with me.
@MoreAnonymous As for your answer, I have no clue. That isn't my area of expertise. My guy to go to is John Rennie. I am not sure if he can help, but its worth a shot.
I've never asked him these types of questions. But he does know quite a bit about quantum mechanics, and quantum theory.
 
@ScientistSmithYT I'm not sure if I completely agree with that ... I mean this is more of a moral principle ... And I'd like to do it more in the context of some philosophy ... A lot of people learn because their actions have consequences ... If we stop this feedback or give false feedback then Im not sure thats productive ...
@ScientistSmithYT I agree he does! No doubt but the links I provide show even the great Landau had written something wrong in his book
 
@MoreAnonymous Just keep in mind... That when you talk to him, he'll always give you his full attention until he has fully answered your question. He does go slow, but be patient, because he unravels it in a way that everyone can understand. And I enjoy it.
 
6:26 AM
@ScientistSmithYT I agree ... if I didn't respect his position I would have disengaged ages ago
 
@MoreAnonymous Sometimes false feedback like that when ignored can go a long way than when learning. It has its benefits, as well as its things that don't benefit as much. But It depends on how we go about it.
 
@ScientistSmithYT I feel your position in morals is deeper than "be the bigger man" ... Any references?
 
@MoreAnonymous Right there! There's the key! :) respect him just as well as everyone else. Don't just respect someone because of there position, respect a person because of who they are.
Yes you are correct.
By references, what do you mean?
@JohnRennie Hello, how's your day been so far?
 
@ScientistSmithYT by reference I mean any link for exposure on ur ideas on morality?
@ScientistSmithYT While all humans deserve human dignity ... I'm not sure if respecting a human being => respect his ideas
 
@MoreAnonymous I don't have any link for those. I've learned those through experiences I've had. On here, other SE sites and in daily life.
@MoreAnonymous I get that and that's good.
 
6:41 AM
@ScientistSmithYT thats okay ... But I'm betting it exists in some moral philosophy text ... Like I mean which position exists that doesn't would be interesting
@ScientistSmithYT also I'm curious about ur thoughts of Gandhism?
 
I like to do something and if it was wrong, correct it the best way I possibly can. That comes in handy especially when I want to make something. I do a lot of things with electricity and super high voltage. (>200 kV)
I don't know what Gandhism is. What is it?
 
To be fair it's quite broad: en.wikipedia.org/wiki/Gandhism
 
That would be pretty interesting. (Referring to your statement about the texts) sorry, I'm a little out of order for the moment.
I'll take a look
 
But u might wanna explore it? (though I hope you identify with it)
I was so upset with Gandhi when I read our history book:


India was on the verge of freedom due the Non-cooperation movement.
People speculated that the British were going to give into the demand of the Indians.
But then the movement was called off. Why? Because strains of the movement started to embrace violence ... In fact in one instance a police station was burned down ... When brought to Gandhi's attention Gandhi called off the movement ...
 
I was reading it, and I didn't think about how many sections it has in it. But I read a good amount on the 2 section. I'll read it sometime tomorrow. I have to work for a few hours at an aquarium. But I'll read all of it.
Huh. I've never read that in a history book I've seen.
 
6:50 AM
@ScientistSmithYT its on wiki

https://en.wikipedia.org/wiki/Non-cooperation_movement#Impact_and_suspension
"Contemporary historians and critics suggest that the movement was successful enough to break the back of British rule"
 
Oh, that's pretty interesting. Yeah, we never got taught that in school. At least here in my state.
@MoreAnonymous I'd really hate to cut this short, but its very late here. And I've got to probably get some sleep for my job tomorrow.
@MoreAnonymous But it was very nice chatting with you. I'll look forward to chatting more tomorrow when I can.
 
@ScientistSmithYT Ping me any time bruv ... Also I am at work :P
 
7:05 AM
@MoreAnonymous Will do. :)
 
@MoreAnonymous yes I read your comments, where have you explained that I am and was wrong?
 
@bolbteppa I actually skimmed (will take longer to internalise) the section 7 u mention ... I was quite curious what Landau himself had to say about time-uncertainity principle and hence the above links ...
Landau has been proven wrong about it ... I'm unable to decipher if thats because of something in section 7 or not ...
Unfortunately Landau has passed away and does not mention this derivation of which his Section 7 may or may not be relevant to ...
 
You think the arxiv paper disproves Landau, even though they do not even reference him?
This is hand-waving upon hand-waving at this stage, if it's not unitarity or continuity failing, it's something else that's failing magically everything is always wrong or flawed, hmm...
 
@bolbteppa yes ... they say it's a common misconception ... Its clear to me they do .. U need the first paragraph to see that and the snippets I uploaded
@bolbteppa did u read the glS answer : "But we use Heisenberg's equation to obtain the result!" section ... he limits the scope of the applicability of the derivation
1
Q: Does the Copenhagen interpretation (+ "quasi-classical measuring apparatus") allow one to bypass a derivation's objection?

More AnonymousBackground I previously asked this question, in which I'm trying to better understand this joshphysics's derivation of an interpretation of the time-energy uncertainty principle. And the gist of what I get is (from the answers and the chatroom) within interpretations of quantum mechanics which ...

In fact, things have made progess since Landau ...

due to some collapse model, or if one adheres to the view that the non-unitarity of measurement is an effective description of a unitary process in which some of the information is neglected, à la Zurek).
I'm not sure what Zurek would have said ... but man I would have loved to hear it
 
7:26 AM
You clearly do not understand the snippets you uploaded if you think they are contradicted by the first paragraph of the arxiv paper, there's a glaring contradiction already in the fact that the paragraph talks about $\Delta t$ as the length of time of a (single) measurement, whereas in the Landau chapter it talks about $\Delta t$ being the time between two successive measurements,
even worse the snippets are talking about fundamental measurements bounds when verifying the law of conservation of energy not " the accuracy error in that" (single) measurement which your paragraph discusses, it is clear you are just hand-waving in another objection to time-energy for some reason after you think this unitarity and continuity nonsense failed
 
@bolbteppa Alright ... I'll have to get back to you on this one later (since I'm in office) ...

Lemme ask you what you think of glS answer (which is something I can see as plausible ... Note: I also see your position as plausible)
 
How does this childish map from a pre-measurement state to a post-measurement state which is non-unitary have any relevance to anything, it's completely ignoring the time evolution of the quantum system + apparatus and their interaction, only focusing on the system at two different times, you have spent days trying to say that this magical function somehow causes the basic equations of quantum mechanics to somehow break, even worse somehow implying continuity breaks
It is honestly astounding to see this level of hand-waving go on for days, with now another layer of hand-waving via this new time-energy objection, almost like the goal from the beginning was to find flaws in QM randomly through the time-energy uncertainty relation...
 
@bolbteppa I'm also curious how does one sneak in an error in 2 measurements when one measurment doesn't have error?
@bolbteppa I hope u see my comments on ur side (perhaps not as strong)
 
That's what the whole point of that section you've been quoting is talking about...
 
@bolbteppa feel free to comment or add an answer??
 
7:35 AM
I really can't figure out what you meant by saying I am and was wrong, not even how you got to that conclusion
 
7:48 AM
@MoreAnonymous I think we can finish with this discussion
 
8:26 AM
@bolbteppa sure ... lemme end with 2 things:

"about $\Delta t$ as the length of time of a (single) measurement, whereas in the Landau chapter it talks about $\Delta t$ being the time between two successive measurements,"

How does one talk about an error in a "(single) measurement" without talking about successive measurements ... Surely the misconception was not I measure energy and that has some kind of $\pm \Delta E$ (rather than an eigenvalue of the hamiltonian) ... which is what led me to believe they were talking about the same thing... It was extreme of me to say u were wrong withou
 
8:47 AM
fuck me the simultaniety bundle requires the use of a Kaluza-Klein metric
bloody hell
"Three ways of defining the connection will be proven to be equivalent"
Ooooh
 
I feel I can read your thoughts in real time by looking at the chat messages :P
 
9:07 AM
If I were you I'd read a physics book instead :V
 
Ouch! gotta go to burn ward!
 
Read a regular QM book and if you really want a book on QM measurement try Streater or Jammer
Streater is particularly entertaining because it's the angriest physics book you'll ever read
 
Can I ask for the spoiler (will not ask u to explain why and I will read the book) on what does it have to say about the question (which I suspect u know about and I dont wanna post in chat)
?
 
I don't know what specific question you mean but I suspect you have not read a whole lot of physics by a wide margin and I would recommend not to sweat it until you do
There are many more questions you'll sweat about after reading up on physics and they will be much worse and not necessarily have an answer
 
Alright ... I'll read it ...
Also I pinged u earlier about something like:
Galilean relativity means principle of relativity in Galilean Transformations
Any thoughts?
 
9:17 AM
I'm not sure what that is supposed to mean but the classical action is invariant under Galilean transform, yes
 
Wait but why is then "the laws of Special relativity hold in an infinitesimal region around a freely-falling observer" akinned to GR?
I mean why can't I have this in SR?
 
Well that is also true in SR, trivially
SR is true in an infinitesimal region of SR!
 
I feel theres something deeper going on here? Care to elaborate
 
if you mean why galilean relativity isn't true, that's because the relation is different
The relation between GR and SR is that SR is true locally in GR, via the exponential map
ie the local structure of the tangent bundle is the same
That's not true of galilean relativity and SR, their local structure differ
Although there is a relation, but that's an Inonu-Wigner group contraction
ie : the Galilean group is the contraction of the Lorentz group for $c \to \infty$
 
"if you mean why galilean relativity isn't true, that's because the relation is different"
no not asking about that
"Inonu-Wigner group contraction" (how many modules of GR did u do??)
Okay ... sigh rusty with diff geometry
Anyway:

"the laws of Special relativity hold in an infinitesimal region around a freely-falling observer" = equivalence principle in GR

"the laws of galalien relativity hold in an infinitesimal region around a freely-falling observer" = equivalence principle in Newtonian Mechanics
 
9:26 AM
well you can but it's trivial
 
really ??? What's that??
 
The laws of special relativity hold globally around a freely falling observer
so by the by they also hold locally
but you're not really adding any new informations
 
yes .. Just as galalien relativity hold in a global region as well
 
For an inertial observer, anyway
things get trickier for accelerated observers
 
I'm okay with paying the price of mischaracterising gravity as a force for this equivalence principle
in SR
 
9:28 AM
Well there's no gravity in SR
So you should be fine
 
But there are forces ...
 
Sure
But, importantly, forces can't be swept under the rug with coordinate transformations
If a force is applied to an object, it is no longer an inertial observer
 
I'm wondering if some kind off approximate of the equivalence principle can exist or is there some fundamental reason of why not?

freely-falling observer automatically assumes I'm talking about non-intertial frame right?
 
Free-falling implies that it is only under the influence of gravity
Therefore a geodesic
The equivalence principle works in GR because it is built in the theory
it's true in any metric theory of gravity due to the existence of Riemann normal coordinates
 
"it's true in any metric theory of gravity due to the existence of Riemann normal coordinates" - I'm sure I can dig out some crazy theory against that :P
 
9:34 AM
Oh I can too, easily
Take a metric that isn't $C^2$ will do it
Since Riemann coordinates assume the existence of unique geodesics in some neighbourhood
 
Anyway we're digressing ...
I could talk about freefalling in Newtonian Mechanics too ...
Which has it's own kinda equivalnce principle (not a useful one but still)
 
It does indeed
 
I'm confused what is it about what is it in SR (where I can talk both about kinematics and dynamics) contrasted to Newtonian ... We can't have our own equivalence principle there too
 
As said, the equivalence principle is trivially true in SR
Simply because there's no gravity
So any freefalling observer is simply an inertial observer
 
But in Newtonian I can talk about gravity (as a force) ... But in SR there's "no gravity" (not even as a force) ... there's something I'm missing here ... Especially if your under the impression that u take "c to infinity" (in a clever way) and go from SR to Newtonian
 
9:41 AM
Newtonian mechanics can also be done without gravity
and of course, you can add (bad) gravity to special relativity, if you wish
Such as Nordstrom gravity, IIRC
$$\Box \phi = \text{Tr}(T)$$
I think
 
Would I be able to define an equivalence principle for this gravity in SR?
 
This one is actually also subject to the equivalence principle
As it is in fact just general relativity for a class of spacetimes with conformally flat metrics
ie it's GR for $g = e^{\phi} \eta$
From what I remember, anyway
Details may be more complicated but that's the basic idea
 
I think this is what I was looking for when I asked:

https://physics.stackexchange.com/questions/502408/equivalence-principle-holding-in-special-relativity-let-alone-qft
 
And of course you can always do Pauli-Fierz gravity on SR
Which is awful and bad
don't do it
 
Is there any "nice" gravity in SR (obviously not as beautiful as GR but still nice?)
 
9:46 AM
No, that's why we use GR
people tried to put gravity in SR for a few decades but there's no decent one
 
Hahaha ... I see ... Maybe u can add that as an addendum if u answer the question
 
^this is why Pauli Fierz is bad
 
Wait ... why is it still being studied now if its soooo bad?
Its 2006 omg
 
You will never convinced a physicist to not study a useless theory just because it's useless
 
Sounds like my question :P
Anyway its interesting to know it can be done even if it can't be done in a useful manner
 
9:50 AM
Pauli Fierz is equivalent to GR and therefore the equivalence principle also applies
it is just frighteningly awful to use
 
Whoa!!! "Pauli Fierz is equivalent to GR" ... But u said it's SR ... Im wondering what crazy hoops they jumped through?
There is the mind of God vs the mind of Pauli Fierz ... Clearly it's easier to understand the mind of God :P
 
Oh it's not terribly hard to work out
But it is an infinite series
not very pleasant to use
It's basically what you get developping $g = \eta + h$
it is an infinite series, alas
And instead of a coordinate change to Riemannian coordinates you just get some gauge freedom which allows you to remove the field's derivatives at a point
 
So they took GR and converted into the language of SR (somehow)??
Link please - obviously need to go through this crazy math
 
Well no
Pauli-Fierz is older than GR, I think
Although of course back then they used the linear version
It's just the simplest field theory that you can use for gravity
Feynman discusses it in his gravity book
 
"It's just the simplest field theory that you can use for gravity"

I'll let the string theorist s know :P
 
9:58 AM
Gravity is $\approx r^{-2}$, therefore it's massless
It's always attractive, therefore it's of even spin
It bends light, therefore it can't be of spin 0
Any theory of spin > 2 has very bad causality issues, therefore it can only be a mix of spin 0 and spin 2
 
"Feynman discusses it in his gravity book"

It's used as some toy model right?
For educational purposes of GR?
 
the linear Pauli-Fierz theory is just the simplest spin 2 theory you can do
Well back in the 60's and 70's people tried to use Pauli-Fierz for quantum gravity
Since it's very easy to make into a quantum theory
 
How did that go?
 
Turns out it doesn't work, though
Not renormalizable
 
hmm ...
Ah ..
It's always attractive, therefore it's of even spin

Cosmological constant?
 
10:00 AM
Not at all related, no
 
Hmm ... Whats the Quantum view on the cosmological constant
The maximum Ive been exposed to is QFT is curved spacetime
 
If you're having troubles understanding special and general relativity
I would probably leave quantum gravity aside for now
 
Yea ... ur right ... :/
 
hmmmmmm
8
A: How can answerers learn, if the downvotes on their answers are not justified?

rob Is there a way for moderators to act as intermediaries between users who provide an answer, and users who have downvoted said answer? As a moderator, that's not a job that I want. Users who can't communicate in a civil manner with each other on our site can spend their time elsewhere. This...

@rob I approve of your use of made-up anecdotes to connect with OPs =)
=P
 
Just send them to the chat
i will yell at them for their bad questions
 
10:05 AM
@Slereah any recommendation for a book on GR I finding myself with way tooo much time since I get time for physics in office (like now :P) ... Something which also brings SR in light of GR ?? I was thinking of using the Kip Thorne book?
 
My usual recommendation for a good GR intro is Callahan's The Geometry of Spacetime
It's not a great GR book, it doesn't go very deep into GR, but it is a nice introduction that spends a lot of time explaining things
 
Does it use diff geo?
 
Well yes, it has to to some degree
 
I could brush up at that too while Im at it
Any book recommendation for diff geo as well (in the light of GR)
??
Maybe one book with both of them?? (I dont mind a massive book)
 
most GR books have enough diff geo in them
 
10:11 AM
@Slereah U have know idea how bad they can teach GR in uni .. Regretted taking this module:

https://www.dur.ac.uk/physics/modules/2018/phys4201/
 
I have been to uni so I know
 
10:27 AM
@Slereah I was under the impression u went to some "kickass" uni from the knowledge u display
 
Bad news : unis mostly suck
You have to do most of the work yourself
 
@MoreAnonymous John Baez lists some recommended GR books on the intro page of his GR tutorial math.ucr.edu/home/baez/gr/gr.html The tutorial itself is quite good, although as he says, it's a bit disorganised, and it's a bit old so it just uses HTML for equations, not MathJax. But it's aimed at mathematicians who are comfortable with linear algebra who want to understand the mathematics of GR.
 
10:53 AM
@PM2Ring yea ... Like that guys web pages ... I run into them all the time for example: math.ucr.edu/home/baez/physics/Relativity/SR/acceleration.html
Just read: "But it's aimed at mathematicians who are comfortable with linear algebra who want to understand the mathematics of GR."

I should stay away then :/
@Slereah Agreed ... though sometimes u get really confused what the lecturer was going on about and start having existential (in class) questions ... My pet example ios solid state physics module I took .. My prof loved Kittel so much ud see snippets of that book in his powerpoint lectures :/
@PM2Ring wait ... there are mathematicians who are not comfortable with linear algebra???
 
@MoreAnonymous Yes, he hosts the old Usenet Physics FAQ. He's a contributor to that FAQ, but most of the articles are written by others.
 
Are u sure u didn't mean linear algebra, diff geo , toplogy?
 
@MoreAnonymous I was using the term "mathematician" very broadly. Someone may be interested in & talented at mathematics, but they haven't learned linear algebra (yet).
 
Ah ... I'm better than this average "mathematician" :P in maths!
 
Archimedes, Fermat, and Newton were, without doubt, great mathematicians, but they didn't know linear algebra. ;)
 
11:03 AM
Bad news : solid state physics professors all love Kittel
Kittel is literally the bible of solid state physics
It was passed down straight from God to Kittel himself
On stone tablets
 
@Slereah Have u read Simon (oxford) ...that book was sooo much better
 
I did not
Partly because I don't actually care for solid state physics
It all happens on a flat spacetime
Real snooze fest
 
I remember the whole class hated that book but couldnt get it removed from the recommended textbooks ... ugh
@Slereah I remember our GR lecturer saying they had done something with the GR/diff geo concept ... I know Im being vague .. But Im googling to see if I can find it
I settle for this now :P

https://physics.stackexchange.com/questions/158416/is-differential-geometry-used-in-solid-state
I'm pretty sure he wasn't talking about holography and superconductivity ...
That much Im certain
 
11:20 AM
A lot of physics's math crosses over
since the math structures tend to be interrelated
The very worst one I'm aware of is statistical manifolds
There's a differential geometry description of thermodynamics
In mathematics, a statistical manifold is a Riemannian manifold, each of whose points is a probability distribution. Statistical manifolds provide a setting for the field of information geometry. The Fisher information metric provides a metric on these manifolds. == Examples == The family of all normal distributions, parametrized by the expected value μ and the variance σ2 ≥ 0, with the Riemannian metric given by the Fisher information matrix, is a statistical manifold. Its geometry is modeled on hyperbolic space. A simple example of a statistical manifold, taken from physics, would be ...
terrible
 
@ScientistSmithYT I am not suggesting something I myself would not want to do. I did not use any rude words. This chat and meta has recently been the fighting ground between these users. It looked like another argument was going to break out. I was merely suggesting that it would be smart to just walk away so that another argument would not break out. Giving advice and saying something someone doesn't like isn't being rude. I merely made a suggestion. That is all.
 
11:37 AM
@AaronStevens hi
Can you help me in visualizing the plane of body
@AaronStevens please sir I will do. The problem by my own, but I not able figure to plane actually question was this
@AaronStevens A stationary electric dipole h=pk^ where h is electric Flux of dipole, Apositive charge q mass m executes circular motion s at constant speed in the field of dipole.
 
12:07 PM
@Slereah is there any physics concept that uses topology and stays away from differential geometry?
 
@PM2Ring @Slereah @SwapnilDas @MoreAnonymous @Loong any body can help in above
 
@MoreAnonymous QFT has vacua topologies
 
Ah ... I think somehow Witten was involved here by connecting it to knot theory ??? (havent understood that one ... Maybe one day I will)
 
No it's just the topology of the vacua
ie : the Higgs vacua has the topology of a circle
 
12:29 PM
Topological defects are linked to vacua topology
 
guys, if atoms forming a gas float far from each other, how can we assign a volume to it? if it is in a container, perhaps we'd say the atoms, or molecules, reach every corner and thus its volume is the container's, but what about when it's in the air?
 
IIRC it's something like $k$-dimensional defects are linked to non-trivial $n - k$-dimensional fundamental groups of the vacua
Homology groups*
Oh wait I guess it's more $k$ for $n - k - 2$
ie if the number of connected components isn't trivial $H_0 \neq \{1\}$ then you have domain walls
If the fundamental group $H_1 \neq \{ 1 \}$ you get cosmic strings
etc
Oh wait it's the homotopy group
 
12:51 PM
@yuvrajsingh Please do not ping random users if you just have a question. Just ask your question and if someone can and wants to answer it, they will.
2 messages deleted
And don't be so rude.
 
@Loong sorry if you feel that
 
rob
1:11 PM
@EmilioPisanty The connection between them is exaggerated, but both of those things actually happened.
 
1:41 PM
On SO, I accidentally voted on the wrong post, when the page refreshed while I was clicking. Of course, I noticed it straight away, and fixed it up. But I think it'd be possible to do it without noticing if you blinked while the page refreshed. :) Once I posted an answer (on SO) that got downvoted within a few seconds, and I can't figure out any other reason for a downvote - the answer was correct, and it wasn't an answer to a blatant "gimme teh codez" homework question.
 
1:52 PM
@PM2Ring hi
 
@rob =P
 
@yuvrajsingh Hi.
 
@MoreAnonymous depends on your tolerance for differential geometry, but topological physics within condensed matter is quite light on the diff-geo
ditto with the rest of the resources at nobelprize.org/prizes/physics/2016/press-release as well as (probably) the Nobel prize lectures from that year
 
@EmilioPisanty thanks :) .. will check them out :)
 
@PM2Ring Can you help me in visualizing the plane of body
(removed)
@PM2Ring A stationary electric dipole h=pk^ where h is electric Flux of dipole, Apositive charge q mass m executes circular motion s at constant speed in the field of dipole.
@PM2Ring I do not need answer, but I can't visualize it
 
2:10 PM
1 hour ago, by Loong
@yuvrajsingh Please do not ping random users if you just have a question. Just ask your question and if someone can and wants to answer it, they will.
 
Hm
Apparently the mathematican equivalent to simultaneity bundles are the Landau submanifolds
 
@yuvrajsingh As Loong said, Just ask your question and if someone can and wants to answer it, they will.
 
@yuvrajsingh this is not appropriate.
1 hour ago, by Loong
@yuvrajsingh Please do not ping random users if you just have a question. Just ask your question and if someone can and wants to answer it, they will.
If you're looking for a chat suspension, explicitly ignoring instructions from a moderator immediately after they've told you to stop a certain behaviour is a good way to go about it
 
I think it's unanimous. :)
Also note that pinging people to answer some random question is a symptom of being a help vampire
 
2:30 PM
@MoreAnonymous (though that said: I generally find that the low level of understanding of the diff-geo background of the invariance of things like Chern numbers among topological-condensed-matter folks is a pretty negative thing -- it leads to an undue 'totemization' of those invariants without any real understanding of why they're there and why they have the forms that they do. At least as a general trend among some of the people I've been in contact with, dunno how broad it is.)
 
2:41 PM
morning folks
 
0
A: Why does the interaction energy for the electric fields of two point charges vanish over any shell smaller than their separation?

Emilio PisantyHmmmm. It seems that OP was too quick on the trigger with this question, and posted here before thinking all that carefully about the problem. The result follows cleanly and simply from the integral form of Gauss's law when suitably interpreted: the angular integral, once rephrased as $$ E(r) = ...

damn OPs
always posting before they think
same with this guy:
0
A: Can one make a synthetic dimension "curl around" into a cylinder?

Emilio PisantyThe simple answer to this is "yes, go read the paper". Indeed, the OP is somewhat negligent in their post, since the Celi et al. paper plainly states in the introduction that We also show that by using additional Raman and radio-frequency transitions one can connect the edges in the extra dim...

8
A: What are the "strong", "ultrastrong" and "deep strong" coupling regimes of the Rabi model?

Emilio PisantyThe OP's characterization of these regimes is not quite universal, and there is some variation. This is partly because there are five important timescales for a Rabi-like system: the resonance and driving frequencies, $\omega_0$ and $\omega$, and the coupling strength $g$, but also the cavity dec...

this guy was alright, I guess
hi @Semiclassical
 
correct me if i'm wrong but a hamiltonian can be set up in a rotating reference frame right?
 
@EmilioPisanty an imperfect analogy: if you just based your knowledge of QM on what people had figured out in the early days of the subject, you could be forgiven for thinking that QM was just about assigning integer values to certain quantities
 
@Semiclassical I don't think that analogy works at all
we know why Chern numbers are quantized -- it's the Gauss-Bonet theorem
 
2:48 PM
When those are really just special cases of the quantum formalism
 
but I see a fair number of people just magic-izing that fact
@SirCumference yes, this is possible. Heck, some people even write whole papers about this stuff
 
Sure, that’s what I mean: the view that QM is “just” quantization of certain formulas may have made sense in the early days, but progress only came when they were able to move beyond that
 
@EmilioPisanty welp that works haha
 
@Semiclassical no, that is stuff that nobody knew and then we found out as a discipline
the Chern-number stuff was known very explicitly to the discoverers, it's just the people climbing onto the train that can't be bothered to find out what the background is
@SirCumference ;-)
@EmilioPisanty it seems I can't even chastise myself
@rob (or any other mod) any moderatorial thoughts on rolling back that edit?
 
3:19 PM
@Semiclassical been there done that ... (ex account)

https://physics.stackexchange.com/questions/271376/quantum-mechanics-in-a-non-inertial-reference-frame
Sorry wrong guy tagged @SirCumference ^
 
k
"Apparently you can fold a piece of paper 42 times and reach the moon! 42 is the answer the everything after all! Oh, Douglas Adams, you clever son of a b*tch." source: physics.stackexchange.com/questions/113482/…
From where these people come from?
 
@AbhasKumarSinha how did u even find that question ... but to be fair they should have called it 42 theory rather than M theory then they would have got waaaay more funding
:P
 
@MoreAnonymous Crazy skills
 
@AbhasKumarSinha And here I was satisfied with my google skills ... Do u even use the PSE search or go for google?
 
@MoreAnonymous There is no perfect thing for everything
 
3:35 PM
@AbhasKumarSinha Hybrid approach ... Impressive indeed ...
 
@MoreAnonymous that's skils! XD :)
 
@EmilioPisanty well, yes, but that’s my point: people treating Chern numbers like magic seems analogous to a physics student nowadays seeing the various quantization formulae and concluding that QM is just a matter of figuring out what integers to insert where
In both cases, there’s underlying mathematics/theory which is the real story
 
rob
@EmilioPisanty It's a good edit. Your subtle self-deprecation was clever, but the failure mode for "clever" is often "asshole." If you decided to put it back you might write "OP (me)" for skimmers who are looking at content but not at author names.
 
3:58 PM
> the failure mode for "clever" is often "asshole."
good point
 
@EmilioPisanty I'm so surprised in the original quesiton where u edited the accepted answer no one even mentions QFT

https://physics.stackexchange.com/questions/502789/which-temperature-transformation-does-qft-allow?fbclid=IwAR09TV2Wtz-Fbs4l4jN2hReL-Y5cJZekxAMxggpBFke8SJVHdMFh1jM5Fdk
Any idea why that was the case ?? Is QFT's opinion not valid ?
 
@MoreAnonymous sorry, you're addressing me? Can you clarify what you think my involvement was with the thread you've linked to?
 
@EmilioPisanty sorry wrong link (but linked inside it) :P

https://physics.stackexchange.com/questions/83488/is-temperature-a-lorentz-invariant-in-relativity
 
so what's the question?
(a single, concise statement, please. If it's not, then I'm out.)
 
'Cause this is thriller
Thriller night
And no one's gonna save you
From the beast about to strike
 
4:04 PM
@EmilioPisanty why is it among all the answers noone mentions QFT in physics.stackexchange.com/questions/502789/…
 
@MoreAnonymous there are no answers in the thread you just linked
I'm not sure you realize quite how rude your behaviour is right now.
 
I'm at work and with extremely limited time to devote to long-winded threads
 
@EmilioPisanty Sorry I'm seriously not doing it intentionally
 
@MoreAnonymous you're addressing me specifically, instead of other people, because I did a purely-formatting edit on an answer on that thread six years ago?
or is there any other reason to address me?
 
4:08 PM
@EmilioPisanty I saw you add the paper in the edit which made me suspect this was something u were familiar with? Also ur high reputed user (so automatic respect)?
 
@MoreAnonymous I'd rather that automatic respect translated into respect for my time, if it's all the same to you
No, I did not add any references to any answers on that thread
 
Sorry ... never mind its probably a waste of time ..
 
@MoreAnonymous please do your due diligence in figuring out people's past involvement with previous threads before pinging them here (or on main, for that matter)
 
My bad ... Just rechecked ... U reformatted a link ... My bad
 
the edit in physics.stackexchange.com/posts/83494/revisions is very obviously only formatting
this is something you should check, every time, before going on to contact others
otherwise, no hard feelings =)
 
4:11 PM
@EmilioPisanty I apologise this is the first time I've asked a user who was only involved in formatting ... My bad ... Same ..
 
4:50 PM
@NovaliumCompany hmmm I think you got my name wrong...
 
minor rant: if a student joins my intro physics section at the end of the second week of the semester, I'd really appreciate if the system would let me know about it
 
So you decided to go on the professor track?
Or are you just doing lecturing while looking for a job in industry?
 
"teaching specialist"
which basically means "same stuff as you were doing as a grad student TA, but full-time"
 
02:00 - 17:0017:00 - 00:00

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