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00:00 - 16:0016:00 - 23:00

4:00 PM
@JohnRennie I clicked your link and I got this:
To be consistent with data protection laws, we’re asking you to take a moment to review key points of Google’s Privacy Policy. This isn’t about a change that we’ve made – it’s just a chance to review some key points.
 
My paper idea rests on me being able to solve that field
Either that or like
I need to do it via path integrals, maybe
 
We’ll need you to do this in order to continue using Google services.
 
That way I don't need to have the basis for the field
 
user116211
@0celo7 His answers are alwwayyyyys long.
 
(maybe)
Timaeus always sounds like he knows what he's talking about but his answer will never be an answer to your question
 
4:03 PM
@DavidHammen that's odd, the link is just https://www.google.co.uk/search?q=mexican%20hat%20potential
 
user116211
He never came in chat though.
 
@JohnRennie thanks that's awesome! Had not heard of that name before lol
 
Chrome has told be before that google.com is known to carry malware
 
user116211
@Slereah: Did you ever try Physics Overflow?
 
^
PO is generally better than PSE
No tyrannical moderation
 
4:05 PM
Well I can send my question that way I suppose
Import request sent
 
@JohnRennie It turns out I wasn't logged in to any of my google accounts. I have three (soon to be four, hopefully): one for work, another for stuff peripherally related to work / my nerdishness (cough physics.SE), and another just for fun. As far as I can tell, there's no way to delete my google account that was specific to my previous job. I just can't access it (which is a good thing). I'm trying to convince my new employer that my previous employer had a good idea.
@Ocelo7 -- Be careful, you might get what you asked for. While PSE's moderation is light, it does not let me tell you that you must be a moron since your left arm is much longer than is your right arm. PO has no qualms about that.
 
PSE's moderation is light?
 
@DavidHammen I don't think there is a point in engaging in this discussion ;)
 
@0celo7 The Shog once called the PSE moderators "kittens by comparison" to the ones at MathOverflow.
 
Calling a black-hole colored pot a "somewhat dark cooking device" is a bannable offense here.
 
4:14 PM
Take that for what you will.
 
@dmckee MO is for professional mathematicians.
 
0celo7 just loves being a victim :P
 
@Danu No
 
@0celo7 Read what the tour says about Physics lately?
 
@dmckee What tour?
 
4:15 PM
I really think SO is one of the worst
 
@Danu Currently listening to DMX, that old enough for you?
 
And honestly no one hardly ever answers a question on there, it's mostly speculation and making fun of the person's code
 
Note: I have yet to retake the harassment training at my new job. I do know however that making jokes about one's gender, one's age, one's religion, one's heritage is completely out of bounds. But if your left arm is much longer than your right arm, I can joke about it. That does not fall into the category of "protected", anywhere. The last harassment training I took used that as an explicit example.
 
Sounds like a disability alternate ability
 
@0celo7 Ok-ish. Listen to it at times, but not very much.
@0celo7 Think about the possibilities in bed!
 
4:19 PM
@Danu I need more details
@DavidHammen Is one really long or one really short?
 
@0celo7 Lie down and try it out ;)
 
@Ocelo7 - No. Some details are best left in private.
 
@DavidHammen Eh? Is this a euphemism for having asymmetric genitalia?
 
lol
 
I love the audacity of some of the homework askers. This chap isn't even giving the usual pleas of I tried but can't do it. He's just come straight out and told us to do the problem and post the answer :-)
-1
Q: Show that there can be no net charge in a region in which there is uniform electric field

Harsha Vardhan KRefer above. Electrostatics question. Can you do the proof mathematically and post?

 
4:33 PM
at least offer some money
 
Shall I comment saying I'll do it if he pays in Bitcoin?
 
user116211
Damn! My cv quota is finished ;(((
 
@JohnRennie My body says yes, my brain says no.
 
Hm
 
@JohnRennie -- No,that's probably protected. I was being quite literal when I wrote about having one arm longer than the other. On the other hand, at my previous job, my supervisor (a VP) and the office manager were both females. After grilling me before they made the job offer official, they asked me what I liked to do for fun. I knew what they meant, so I answered "I love taking my three lady friends on romantic walks through the woods and down to the beach!"
My three lady friends? Check my icon. They are real dogs. Quite literally.
 
4:36 PM
I do have the vacuum to vacuum transition amplitude for a free field with path integrals now
I wonder how easy it would be to adapt it to a wormhole scenario
Maybe...
Maybe I should do some GHOSTS???
 
@DavidHammen :-)
 
Imposing some condition on the path integral so that it only integrates on the correct field configurations
Like... $$\int \mathcal D \phi(x) \delta(\phi(x_1) - \phi(x_2)) e^{iS}$$
I dunno
 
@JohnRennie I did it for free.
 
@0celo7 you just answered a homework question. Why did you do that?
 
I'm a rebel
 
4:40 PM
$$\int_{\partial D_1} dx_1 \int_{\partial D_2} dx_2 \int \mathcal D \phi(x) \delta(\phi(x_1) - \phi(x_2)) e^{iS}$$
Something like that
Does that sound like a reasonable thing
Some kind of WORMHOLE GHOST
Like in Event Horizon
 
@JohnRennie dw, I VTC'd
@Slereah Wormhole Faddeev-Popov?
 
@JohnRennie -- Regarding my so-called romantic walks through the woods: My wife has joined me twice on those walks in the last seven years. Both times she has said "never again!" These so-called woods are infested with swamps, mud, briars, spiders as big as one's hands, and poisonous snakes. My arms are a complete mess under UV light. My three "lady friends" (my three female dogs) love it when I let them loose in that mess.
 
I prefer to call it a Lereah Ghost
 
@0celo7 yes, but by providing an answer you're just encouraging the OP to ask more homework questions.
 
B)
 
4:42 PM
@JohnRennie Hmm
 
The reason we don't answer homework questions is to discourage people from asking them. It's not that we're unhelpful bastards, we just don't want to be swamped by people trying to get us to do their homework.
5
 
@JohnRennie I've read all of the meta posts on it
 
probably a smart idea
 
@JohnRennie We're discussing this exact topic in the Mathematics chat right now.
 
@Danu Why didn't you link the chat
I can never find their chat
it always takes me 5 minutes of hunting
 
danke
 
^wormhole ghost
 
good god
 
Hm let's see
 
-2, wtf
 
4:47 PM
A spooky ghost in gauge theory is $\int \mathcal D A \delta(G(A))$
 
I'm a mentor at a potentially competing site that does answer homework questions. There's a big caveat: The person asking the question has to have done some homework. Asking "Do my homework for me!" doesn't work.
 
With $G$ some gauge fixing condition
I think that should be fine too
 
@DavidHammen I've been stuck on a homework problem for a day now
 
@DavidHammen most of us would regard the effort put in by the OP as an important factor. Where the OP has made a genuine attempt to tackle the problem themselves we'd probably stretch a point and answer, or at least give a hint.
But all too often the OP is just being lazy.
 
So ask at that competing site. You should be able to find it if you have a decent amount of google-fu. Since it is a potentially competing site, I am not going to mention it by name. @JohnRennie, you can let me mention it by name.
 
4:50 PM
lol @0celo7 deleted it yourself after all?
 
@Danu Well clearly it was unwanted!
 
@DavidHammen It's fine---you can name Physics Overflow.
 
I thought I had a nice solution though :(
 
Nobody's going to care if you mention it.
 
Oh gosh. It is not physics overflow.
 
4:51 PM
Physics Forums?
 
This isn't a competition, and we're not jealous of other sites.
 
@ocelo7 -- Bingo!
 
I hate Physics Forums @DavidHammen
You can never get answers from the threads
They all have the following layout:
Problem I need help with
Some dude giving a vague hint
Pointless back and forth about stuff I already know
Oh! OP figured it out but doesn't explain
 
Forums have their place, but the PSE is specifically intended not to be a forum. If people wish to discuss things that's what this chat room is for.
 
Also physics forum has a lot of ads
 
4:54 PM
Hi guys, I have a wavefunction collapse question that does not involve entanglement:

Suppose I have a set up containing one electron. 8 light minutes away I placed a detector B that can read the spin of the electron (and can flash red if spin up, green in spin down).

Suppose I have a friend Ann standing next to detector B.

Now I use another detector A next to the electron unit to measure my electron spin. Suppose my measurement collapse it to spin up. will I expect 8 minutes later, Ann will inform me her detector flashes red?
 
Hm
If I have a follow up question to my wormhole question
 
A first-principles proof that the normal bundle is a manifold might be the hardest thing I've done in a while.
 
Can I call it [question] II : electric boogaloo
 
@DavidHammen there are no rules against mentioning competing sites. For the record.
 
@Danu I take if you wouldn't care to provide a hint?
 
4:56 PM
@0celo7 What?
 
@Danu I'm trying to prove that the normal bundle is a smooth manifold.
It's not working
Yes, I checked Lee, yes I understand his proof.
But I have literally none of those tools available to me.
 
Physics Forums have very strong reasons for that format. This site (physics.SE) is not intended to be a homework help forum. We generally close questions related to homework, for good reason. Physics forums does not do that. Helping students to learn is their primary reason for being. That means lots of what would be duplicate questions here get posed, over and over again.
3
 
@0celo7 Normal bundle to what?
 
@Danu A normal bundle of a manifold in $\Bbb R^k$.
I don't have slice charts available, I'm not even sure if I have frame fields
 
A submanifold you mean?
An embedded one?
 
4:59 PM
@Danu See, Milnor and GP define manifolds as embeddings
but they don't use the term "embedding"
 
Right, I'm off to read this weeks New Scientist. See you all later.
 
My guess is that when the electron get projected to e.g. spin down eigenstate, that information will need to travel with an upper bound of the speed of light to reach Ann, thus she will see the detector B flashes red. However I am not really sure if there is any chance the information becomes distorted somehow during the travel and causes the detector B to flashes green instead
 
@JohnRennie See ya!
 
I'm stupid, I haven't checked GP...
It might be in there...
Aha!
At least a partial proof
@Danu Thanks for letting me @ you :P
Now you know what it's like to be ACM
 
@JohnRennie @JohnRennie See ya!
 
5:02 PM
@0celo7 you could try to go through corollary 10.36 in Lee.
Existence of local frames is a triviality anyways
 
@Danu I know how to do it via bundles!
 
Ah, shite he uses slice charts there too.
 
I'm saying I don't have that technology available
 
So prove the technology first?
 
@Danu I know!
@Danu Yeah like you're supposed to invent slice charts for an exercise without a hint?
@Danu and Milnor does not even define the notion of a fiber bundle
 
5:04 PM
What class is this anyways?
I don't believe that submanifolds are not discussed before normal bundles.
 
@Danu Differential topology
 
Then you should be able to use "standard lore" i.e. slice charts IMO :P
 
@Danu Milnor does not really discuss these
GP uses slice charts too :/
Guess I'm inventing slice charts in this proof :)
 
5:30 PM
@Danu nope
 
@Danu I guess Milnor wants me to magically come up with the theorem on page 15 of GP...
These exercises are way too hard
 
@ACuriousMind OK.
 
Hm
Maybe my spooky ghost idea should first be tested on a cylinder spacetime
 
5:46 PM
Hory shite it's already the 12th
 
Yes
AMA in two days
 
How are you doing @ACuriousMind
 
Beginning to feel alive again after a terrible hangover
 
So @ACuriousMind
What do you think of the
SPOOKY WORMHOLE GHOST idea
 
Is that a movie pitch or a physics idea?
 
5:57 PM
@ACuriousMind Had a good time?
 
Can't it be both
I'm trying to compute quantum things for spacetime surgery wormholes
 
@Danu Yeah, the party was excellent
 
And I have this vague idea to do it with path integrals with the following method
$$\int_{\partial D_1} dx_1 \int_{\partial D_2} dx_2 \int \mathcal D\phi(x) \delta(\phi(x_1) - \phi(x_2)) e^{iS}$$
Or something like that
Though technically that's only half the conditions for spacetime surgery on fields
There's also $n_1 \cdot \nabla \phi(x_1) = -n_2 \cdot \nabla \phi(x_2)$
Not sure if I can use both here
 
@Slereah I'm not sure what that's supposed to be
 
Well similarly to Fadeev Popov spooky ghosts, I'm trying to remove all field configurations where the field isn't of the same value at the boundary of the wormhole
Does that sound like a good idea
 
6:01 PM
of the same value as what?
 
Well the field that enters the wormhole at a point and the field that leaves the wormhole at the identified point should have the same value
 
If the two points are identified, i.e. the same point, how could it have a different value?
 
Well the trick is
I am doing this as though it was Minkowski space
But with identifications to make it work
(Because otherwise I have no idea how to solve it)
 
Why is a field "leaving" or "entering" the wormhole to being with - a field is just some assignment of values to spacetime points, what do you mean by "entering"?
You might need to describe the setup in more detail before I can say anything about this
 
Well Minkowski surgery is like
Take Minkowski space
Remove two identical closed volumes from it
Identify the boundaries of those removed volumes
 
6:06 PM
@Slereah What is the metric on the remaining piece?
 
The metric is... kind of weird
Like it's Minkowski space everywhere, but you have kind of a Dirac distribution at the boundary
Metric is $C^1$, smooth everywhere except the boundary
 
wew lad
that seems terrible
What's on the docket today...failing at topology exercises...check
 
It is less bad than doing a smooth intrauniverse wormhole, tho
I tried my best on that front but jeez
 
Obtain more food
Wrapping paper
I need to find a printer
oh and homework
 
The Q&A really needs to be cleaned up. Last few questions have been horrendous!
 
6:11 PM
I can ask some good questions
 
Fire away about 10 and the bad ones will get pipelined down @0celo7
 
@MBarbosa what's the link
 
Hm
 
@0celo7 to a bad one?
 
I recall that what's his name has a whole book section on path integrals on circles and such
I should try to see if my spooky ghost idea is equivalent to that at least in that case
 
6:17 PM
-4
Q: Acceleration of the body

meemansa mishraQ) If v is the velocity of a body moving along x-axis, then acceleration of body is: (1) dv/dx (2) v dv/dx (3) x du/dx (4) v dx/dv Please provide the explaination of the correct option to me as well.

 
👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻👻
 
> Congratulations! Your $5 Gift Card for The Springer Shop
Why thank you Springer
@MBarbosa no to the Q&A
 
$5 won't even buy you a one page article on Springer
Hell
 
user116211
@Slereah not even a comic book ;((
 
@0celo7 I was meaning the Q&A feed in general but "Acceleration of the body" is a good example ^^
 
6:19 PM
I don't even need to do it for QFT
 
@Slereah It also doesn't apply to MyCopy books >:(
 
I could try it for non-relativistic QM
Hm
 
user116211
@0celo7 why not $50? Damn Springer ;\
 
I could try to apply a wormhole for non-relativistic QM, first by hand and then by path integrals
Maybe
at least within some limits
It's pretty easy to do for geodesics rather than fields
 
6:38 PM
Why is @JohnDuffield here
 
He has the evidence
 
oh god
I thought I cleaned that up
 
Lens spaces awwyis
 
typo after "Figure 2"
missing period
 
@0celo7 you might be pregnant
 
6:41 PM
@0celo7 ?
Ah
Its name.
Thanks
 
I guess I could have been more precise :P
 
Wow, you guys are drawing a "conlinder" (basically imagine folding a cylinder except the cross section of that rectangular piece of paper is a cone)?
 
what
 
anyway, what kind of pussy needs pictures
obviously one who doesn't understand the theory
 
* sorry mistake, that's not a conlinder, because the base of the cone (e.g. in $S_z$) is held fixed as it glue around $S_w$*
So I am guessing, all sets of points indicated by the blue dots and line (since the previous line said the identification is an equivalence class, it is kinda implying I basically have many such pairs of blue points and lines on figure 3, except not drawn for clarity?) are the points being identified in lens space?
and that the two blue points substends an angle of $e^{\frac{2\pi i}{p}}$ relative to the xx' line?
 
7:01 PM
what if all the aliens are dumb tho
Maybe they're all space bogans
 
he obviously completely missed the point -_-
 
@Slereah I'm pretty sure e.g. ACM is an alien
 
When an exit path exists, they will go straight through it, this is their nature that you cannot change
 
7:36 PM
@JohnRennie awfully generous of you to offer this
(IMO)
 
@JohnRennie was the homework question police for today
 
 
1 hour later…
8:49 PM
.
What is shift+enter command or iphone
 
0
Q: Quantum oscillator transition amplitude

Martin NikovskiI have a quick question regarding an equation in my textbook. It's about calculating the probability transition amplitude of a quantum oscillator. Why is this true? The difference between the first and the second row seems to be small. There is a minus sign before $\dfrac{i}{\hbar}$. In the to...

???
@Slereah you might have a better chance posting your stuff on Math SE
 
Yeah might give it a try if it doesn't work out
Though I'll have to do it in a more math friendly fashion
Is there a name for that math-wise
It's kind of a connected sum of a manifold to itself
 
What?
A name for what
 
The whole cutting out a volume and identifying it
 
> Since your interests are GR and Quantum Field Theory, with maybe some insight into Quantum Gravity (QG), could you summarize with some technical reasonings, what is known and what key findings are still needed for Hawking et al's conjecture that the BMS super translation symmetries and conserved charges are the basis for doing away with the information paradox?
lol
you're fucked if you have to answer that
 
9:03 PM
yeah I don't know shit about that
 
@Slereah that's literally what surgery is
 
I guess
mb there's a math paper about it
Like solving PDEs in surgery manifolds
 
guaranteed
there's multiple shelves of books on surgery in the university library
(the topological kind)
 
yeah but do they try solving PDEs on 'em
 
Don't know
@Danu talked about surgery once or twice
 
9:06 PM
Also more importantly I need the Green function
 
My leg hair is shedding :(
 
I've seen a few papers working out specific solutions on surgery spacetimes
But I want the vacuum expectation value of things
 
oooo, shoe store telling me I've got a reward
 
Surgery theory was introduced by... Milnor
Damn Milnor again
Oh god I hope I don't have to learn Morse theory
 
You'll have to learn topology first
 
9:13 PM
Eh
Maybe I can keep it blackboxed
Hm, what to search for
I need to think like a topologist
I'm guessing they would talk about HARMONIC FUNCTIONS
Can't really find shit on the topic
 
9:37 PM
@0celo7 Hmm?
 
@Danu Mmh?
@Danu Slereah needs help with surgery
 
Yes
I need a disk cut out
 
I only know a tiny bit about the topology of surgery---no PDE's
 
10:33 PM
damn
 
already deleted
 
hahahaha nice. Pretty unclassy to call someone out on the meta like that
 
what happened?
 
someone called out CuriousOne on the meta
got deleted though. It was a pretty long grievance
 
oh?
What was it about
 
10:44 PM
The user claimed he was giving out wrong information about QIT
most of them were on that user's questions which makes it even funnier
 
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