The h Bar

0celouvsky

12:05 AM

@BernardoMeurer Or should we learn Brazilian Riemannian Geometry?

@BernardoMeurer Joey Bada\$\$ got a strong 8

DanielSank

Why does everyone care about measure theory?

Gimme a ruler, I'll measure whatever you want.

ACuriousMind

Not everyone :P

DanielSank

Bah. You're a sock puppet.

0celouvsky

@DanielSank This chat is pretty hostile towards measure theory.

I don't know why...it's one of the fundamental tools of modern mathematics.

DanielSank

@0celouvsky Bah!

0celouvsky

12:16 AM

?

0celouvsky

12:27 AM

@ACuriousMind Is this question a symptom of the fact that physicists use "diffeomorphism" for "isometry?"

Actually I'm not sure what physicists use "diffeomorphisms" for.

ACuriousMind

@0celouvsky I can't know the user's mind, and they didn't really give me much to go on, so yeah, that might be it, but it might also be that their confusion lies somewhere else entirely

the "a diffeomorphism is equivalent to a change in the gravitational field" line strikes me as a bit strange

0celouvsky

@ACuriousMind Yeah but that's what physicists say :P

I think physicists use "diffeomorphism" for "coordinate change"

I'm blaming all physicists here

ACuriousMind

@0celouvsky I can't recall a statement that a diffeomorphism is a "change int he gravitational field" off-hand

@0celouvsky Now that is true, there's a lot of confusion in the literature about that

0celouvsky

@ACuriousMind Yeah but you do recall that the gravitational field is invariant under Diff, right?

Well, "recall." It's not true.

ACuriousMind

What is "the gravitational field", anyway?

0celouvsky

12:32 AM

The metric.

ACuriousMind

Ah, yes, then we're in our well-trodden "those things are actually supposed to be isometries" territory again

0celouvsky

@ACuriousMind Yup. Also recall the old "diffeomorphisms are just coordinate changes"

That's doubly wrong because coordinates are on $\Bbb R^n$ and diffeomorphisms are on the manifold.

ACuriousMind

Yes, we've been over this before. As I said, OP hasn't really given me enough in that question to be sure that's what they're confused about

0celouvsky

@ACuriousMind By the way, it's possible to make special relativity generally covariant.

General covariance has no content.

@ACuriousMind I don't remember going over this before.

ACuriousMind

I know, you can make any system generally covariant, it just becomes constrained/gauge in the process :P

0celouvsky

12:35 AM

Dammit QoGS

ACuriousMind

@0celouvsky I definitely remember going over the difference between coordinates changes, diffeomorphisms and isometries before and agreed with you that the standard physical description is hopelessly muddled

0celouvsky

@ACuriousMind Here's a question. Suppose we have $\mathrm{Riem}(g)=0$ on $\Bbb R^4$. What is $g$?

Must it be the Minkowski metric globally?

We know that it is locally Minkowski.

ACuriousMind

@0celouvsky I'm not sure we can say really much about it. After all, take any diffeo $f:\mathbb{R}^4 \to \mathbb{R}^4$ and set $g' = f^\ast g$. Then $g'$ is also flat but $g$ and $g'$ can be wildly different as functions on $\mathbb{R}^4$ depending on $f$.

0celouvsky

@ACuriousMind I mean is there one $f\in\mathrm{Diff}(\Bbb R^n)$ with $g=f^*\eta$?

ACuriousMind

Ah, yes, that's what I was going to suggest next, but I don't know the answer to that question, either

0celouvsky

12:45 AM

$\eta$ being the Minkowski metric, of course.

ACuriousMind

I guess the question is - do the local isometries to Euclidean space you get from it being flat glue to a global isometry

0celouvsky

@ACuriousMind Might as well ask on the main site?

@ACuriousMind Exactly

Seems like a nontrivial question unless I'm missing something

ACuriousMind

@0celouvsky Strikes me as more of a math.SE question, but yes, it's a nice question

0celouvsky

@Slereah You'd be interested

@ACuriousMind Ah, do you remember my Jacobi field proof of the local flatness theorem?

ACuriousMind

Vaguely

0celouvsky

12:53 AM

@ACuriousMind One shows that $\exp_p$ is an isometry of a ball in $T_pM$ onto an open geodesic ball in $M$.

So one just has to show that a flat manifold admits arbitrarily large geodesic balls.

ACuriousMind

Not the geodesic balls again! ;P (Kidding, but I have no idea how one would show that)

0celouvsky

@ACuriousMind You didn't think I'd be doing analysis forever!?

@ACuriousMind Well obviously flat manifolds are not necessarily complete, take $R^n$ minus a point.

Can one put a topological metric on $\Bbb R^n$ that generates the standard topology but that isn't complete?

0celouvsky

1:39 AM

Farewell Mr. Bunting - SNL

►

@ACuriousMind I'm silly.

Universal covers of space forms are isometric to $R^n, S^n$, or $H^n$.

This is well known ;/

0celouvsky

2:01 AM

That proof uses Riemannian geometry...

Wonder about the Lorentzian case

Secret

2:22 AM

Some possible signs of chiral magnetic effect in quark gluon pplasma

Auroroa on uranus

Slereah

3:22 AM

@0celouvsky which one

0celouvsky

physics.stackexchange.com/questions/315374/…

Slereah

I think the most indices I used was for my master thesis

0celouvsky

did u taylor expand there

Slereah

yeah

0celouvsky

jesus christ

Slereah

3:29 AM

Thanks to the fact that any $\mathcal{O}(\eta^5)$ term integrates to $0$

Or was it 7

I forget

It's been a while

Ah yes, the taylor expansion had factors of $\varepsilon$, which in the limit has to compensate with $\eta$

0celouvsky

disgusting

Slereah

This went to $0$ if you had too many terms

so there was a natural cutoff of the Taylor expansion

The result involved $(abcdef)$, which was every permutation of indices possible for $g^{ab} g^{cd} g^{ef}$

that was an arse

Shing

I am a bit confused by prof Valter Moretti's answer:

v

1.) why the general equation of motion is F=ma? // we presume Newton's mechanics in general relativity?

Secret

The ionosphere of mars is layered only in certain regions with local magnetic field

Slereah

@Shing that sounds like a fairly dangerous presumption

0celouvsky

3:36 AM

sadly I'm not doing my thesis on GR

I would have liked to learn about extended objects in GR

Slereah

Oh mine wasn't either

$g$ is a purely spatial metric

0celouvsky

but now I get to learn about the index theorem

that's also cool

Slereah

My thesis advisor wasn't big on GR itself

He was more of a QFT quantum gravity guy

0celouvsky

I see.

> The power gain G of an amplifier is defined to be the power delivered to the load RL divided by the power

delivered by the signal source vs.

circuits class is going to kill me

I will actually die because of this

@Slereah wtf is that

AC source?

Slereah

Seems like it, yes

vzn

3:55 AM

← saw ghost in the shell on sat, imax 3d, liked it... anyone else? :)

Anonymous

@0celouvsky What type of circuits are you learning ?

0celouvsky

amplifiers

not sure how this voltage source can deliver power when there's no current in the wire

:(

Anonymous

It is a grounded AC input

Anonymous

@0celouvsky What? There is current!

0celouvsky

so?

Anonymous

3:59 AM

The ground is considered at 0 potential

0celouvsky

@blue the ideal op amp assumption is that there is no current in the input leads

yep, verified with textbook

so...infinite power?

er, zero power

infinite power gain

seems legit

free energy

Anonymous

@0celouvsky Yes, it is an ideal case.

Anonymous

In reality it is about 10 mV

0celouvsky

what is

Shing

If two objects with equal mass, in a inertial frame falling each other by gravity. then in one of them's own frame - free-fall frame, is it a inertial frame?

Slereah

4:04 AM

no, it's an accelerated frame

Anonymous

@0celouvsky Oh, the input offset voltage. In ideal cases they assume that if this input is 0 volts (i.e. both inputs are at the same voltage with respect to ground), the output should be zero.

Slereah

Inertial frames can only transform in one another by galilean/lorentz transform

0celouvsky

@blue oh, yeah

Shing

@Slereah I see, thanks

Slereah

of course the real problem is defining at least one inertial frame

Shing

4:09 AM

so since everything has a mass, and be affected by another mass (no matter how small it is), then the "free-fall frame = inertial frame thing" is just an approximation, or rather an illustration of something interesting that I do know yet?

Slereah

well we get into philosophical problems when trying to define what an inertial frame really is

How do you prove that an object is subject to no forces at all, etc

or at least no differential forces, as the term goes

0celouvsky

Vishnu might be acting on it, who knows

Slereah

(Yeah I've been reading some Reichenbach lately :p)

He goes on a lot about universal forces and differential forces

Shing

@Slereah can I suggest to Newton's III law

say, if I am in a frame, all things remain unifom motion, then it is an inertial frame

in such a frame

if anything accelerate

then there MUST be another thing in this universe accelerate respectively

Slereah

an inertial frame isn't that objects remain in uniform motion

An inertial frame is just a frame where their motion obeys $F = ma$

Shing

4:14 AM

but we can introduce pseudo force to fit the F=ma?

Slereah

Well no, that is the problem

If you can introduce pseudo forces, then any frame can be an inertial frame

then the concept is meaningless

Shing

so we need Newton's III law to identify which one is really inertial frame?

Balarka Sen

You can introduce the pseudoforce iff you're an observer, inside an inertial frame, outside the non-inertial frame contained in it, right?

Slereah

yes, although of course, the difficulty is thathow do you differentiate an object moving due to forces, and an object moving due to pseudoforces

Fortunately the notion of inertial frame disappeared in GR and we don't have to care anymore

0celouvsky

I don't think Gorgoulhon talks about them either

He just does stuff in every frame

Shing

4:17 AM

haha, that sound something indeed interesting ahead of my studies. Recently I am reading Wheeler's Spacetime Physics. I know quite too few of GR

Balarka Sen

gr is blackmagic

Shing

lol

Slereah

Most of classical mechanics is done with the assumption that most reasonable frames are inertial

so that you don't worry about it

0celouvsky

Just do classical mechanics on the cotangent bundle

No need for frames

Slereah

but of course experiments on earth are subject to the coriolis force and the centrifugal force

it's just small enough that we can ignore it

most of the time

0celouvsky

4:21 AM

Not when doing long range shooting.

Slereah

yeah

The coriolis force can make a sniper miss his target

IIRC I calculated that a shot over 1km would deviate about 20 cm

That's enough to miss a head

0celouvsky

@Slereah my handheld ballistic calculator does it for me

It knows my coordinates and I point it in the direction of the target

Slereah

Oh Mamericans and their guns

did u get it at walmart

0celouvsky

I'm off to sleep

Slereah

night

0celouvsky

4:25 AM

@Slereah no, I get quality stuff

Walmart does have good ammo though

Anonymous

4:59 AM

@Yashas Where are you!

Yashas

5:27 AM

@blue studying economics!

Anonymous

5:37 AM

@Yashas phew! By the way, I couldn't understand something. Why are stationary waves formed by de broglie electrons between atoms arranged in 1D array ?

Anonymous

I mean a stationary wave can be formed when two travelling waves superpose...but in case of atoms are the electron waves travelling? :/

Anonymous

I'm so confused

Anonymous

This was the question ^

John Rennie

@blue I would guess it means the wave reflected from the atoms interferes with the incoming wave and a standing wave is formed as a result. In any case it's obviously just expecting you to spot the link between the spacing and de Broglie wavelength.

Anonymous

5:47 AM

@JohnRennie Could you please explain the meaning of "wave reflected from the atoms" ? Which wave do you mean?

Anonymous

By the way, do electron waves travel from one atom to another?

Anonymous

I thought they are restricted to their shells unless the form compounds

John Rennie

@blue The incoming electron beam scatters off the atoms in the crystal, and as a result it is (partially) reflected. This is no different to the way that light is reflected.

@blue the phrase electron waves in this context means an external beam of electrons directed at the crustal. The electrons in the atoms of an insulator are bound and are not plane waves, so they do not have a wavelength.

In metals the conduction electrons behave as if they are almost free, and they can be modelled by plane waves i.e. momentum eigenstates. But that's irrelevant to this question.

Anonymous

@JohnRennie Oho! So they mean an external beam of electrons! I thought they meant the bound electrons sort of form plane progressive waves (and superpose to give stationary waves) and that is why I got confused. Thank you! I got it now =)

John Rennie

Hmm, on rereading the question it is ambiguous, but I can't see any sensible explanation other than it's an external electron beam impinging on the crystal.

Anonymous

5:56 AM

@JohnRennie Right, it does seem ambiguous at the first sight. But I suppose that (external beam) assumption will do the job.

Anonymous

And yep, the answer seems to match with that assumption. $\lambda=1 A$

Anonymous

$p=\frac{h}{\lambda}$

Anonymous

$E=\frac{p^2}{2m}=150.6 eV$

Anonymous

And minimum separation is $\frac{\lambda}{2}$

Anonymous

Fair enough =)

user228700

5:59 AM

@JohnR: Morning :-)

John Rennie

@Kaumudi.H Morning :-)

Anonymous

Morning!

user228700

@blue Hey.

John Rennie

@Kaumudi.H You're half an hour early! Feeling bored with work and hungry for lunch? :-)

Anonymous

Well, it is nearly 12 noon =P

John Rennie

6:01 AM

12:30 isn't it? I have an idea Chennai is 5.5 hours ahead of BST.

user228700

@JohnRennie I pop in at any random time b/w 10:30 and 12:00, really.

Anonymous

GMT is 6 AM

Anonymous

So +5:30 is 11:30 AM

Anonymous

:P

user228700

@JohnRennie 11:30 AM here :-)

Anonymous

6:04 AM

@JohnRennie I think it is about 4 and half hours ahead, not 5.5

Anonymous

Anyhow, these timezones are confusing!

Fawad

Indian Standard Time is 4 hours and 30 minutes ahead of British Summer Time
7:05 AM Tuesday, British Summer Time (BST) is
11:35 AM Tuesday, Indian Standard Time (IST)

John Rennie

@blue Oh yes. 5.5 hours ahead of UTC, but British Summer Time is one hour ahead of UTC so a net 4.5 hour difference.

And I thought GR was complicated! :-)

user228700

Speaking of timezones, @JohnR: Dyou remember the discord server in which I have met many many nerdfighters? Vidcon Europe took place over the weekend, for which Hank went to Amsterdam and shot a bunch of footage for Friday's video. The problem is that he couldn't edit it because he left his laptop on the plane. So, he uploaded the footage to a public dropbox folder and asked people to edit it for him; that the best video would be chosen to go up on the vlogbrothers channel by vote.

John Rennie

he left his laptop on the plane - Oops :-)

user228700

6:08 AM

Nerdfighters at the discord server (and sadly, I couldn't be a part of this) worked across over 10 timezones and collaborated on this project. This was the result:

user228700

Our Thoughts from Hank's Places

►

user228700

Although it wasn't selected, it was listed under "Honorable mentions" with the title "Most wonderful".

John Rennie

Cool :-) It's a fantastic sense of community when you get people collaborating on projects like this. I used to be part of a team developing some open source software and it is very rewarding.

Your laptop is easily capable of editing video if you want to give it a go.

user228700

@JohnRennie Indeed :-) Oh, I see!

John Rennie

But it is very time consuming so that's probably best left until that mythical day far in future when THE EXAMS HAVE ALL FINISHED! :-)

user228700

6:11 AM

Lol, yes :-) But also, I'm afraid I have no interesting footage at the moment.

Bernardo Meurer

Good morning folks

user228700

I don't take any videos...

Anonymous

Good morning @BernardoMeurer =)

user228700

@BernardoMeurer Hi :-)

John Rennie

@Kaumudi.H Your laptop is basically the same as the laptop I'm using right now, and I regularly do video work on my laptop.

Fawad

6:12 AM

@BernardoMeurer Good morning.

John Rennie

@BernardoMeurer 7 a.m.!!! Who are you and what have you done with Bernardo? :-)

Bernardo Meurer

Some many hours later... 118GB to go uploading

@JohnRennie I know, I know, I am ashamed of myself

It's just that I go to Azores today

and my flight is at 10

Swapnil Das

@blue Trigonometry and Algebra.

John Rennie

@BernardoMeurer Cool :-)

user228700

(@JohnR: BTW, I wasn't able to be a part of the project because firstly, it took place in the wee hours of the morning here and secondly, I didn't even get to know about it until it was all over, not because I have no skills in video editing but that is also true)

Anonymous

6:14 AM

@SwapnilDas Those books have just too many repeated questions. Be careful.

Anonymous

Don't waste your time on them.

John Rennie

@Kaumudi.H Things tend to be dominated by the US timezone. It's not so bad for Brits because we have a reasonable overlap with US time, but the Indian timezone is just that extra bit out of phase.

user228700

Yes :'-(

user228700

I'm not in a situation in which I am able to stay up all night, carefree.

user228700

One day! (:-P)

John Rennie

6:16 AM

I must admit I find I miss being part of the discussions that happen here when our US members have finished for the day and are having fun. But I'm in bed by then.

Slereah

what's a good symbol for an arbitrary interval of R

$I$ I'd rather keep for $[0,1]$

user228700

@JohnRennie Lol, I also feel sorry that you have to interact with us "kids" and talk high school physics and occasionally food and all whereas if you were up for the U.S discussions, I bet that would be more fun for you :-P

user228700

No need to be a gentleman about it :-P It's true; interacting with angsty teenagers high on raging hormones does not make for the best experience.

John Rennie

Actually I really enjoy helping with JEE level physics. Apart from GR and a bit of quantum mechanics I don't know enough higher level physics to be able to contribute much.

Anonymous

LOL, let us bombard John Rennie with JEE questions now ^ @Kaumudi.H @Yashas

John Rennie

6:21 AM

@blue Better buy 0celouvsky a giant size pack of tranquillisers first :-)

Fawad

@JohnRennie you looks intelligent. Why you choose physics than maths as your major subject?

Bernardo Meurer

The only reason I hate the JEE vibe is that it throws me back to a dark era of my life

user228700

Eyy, I have a question for you; Brits have a reputation to be extremely polite even when they feel like throwing only anger in the other person's face. @JohnR: Have u found that this is particularly true and also, would u say that this is a pro rather than a major con? I mean, if you could have that part of ur upbringing be any other way, would u?

user228700

@BernardoMeurer What, high school?

John Rennie

@Fawad There is a major difference of emphasis between physics and maths. Physicists study physics with the ultimate aim of explaining how the universe works. Mathematicians study maths for no reason other than it's fun.

@Fawad I could never be a mathematician because I always want there to be a reason for the research I do.

Fawad

6:24 AM

in Mathematics, Mar 31 at 21:20, by Danu

Orrrr become a physicist and do all the cool shit but don't really know what you're talking about :D

Bernardo Meurer

@Kaumudi.H University admission exams, yes

My results in the admission exams in Brazil are the proof that there is no justice in life

John Rennie

@Kaumudi.H Brits don't exist as a single group. We are just as varied as every other nationality. Some Brits are cool and reserved while some are in your face.

Fawad

@JohnRennie true.

Anonymous

@BernardoMeurer Eh? Maybe you are getting a negative impression about it due to too many people whining. Out lives isn't that miserable. I can bet there is no greater joy than staying up all night with friends and solving challenging problems =)

Bernardo Meurer

I didn't put any work into it but my scores were great lol. Both my essays were crap but they both got almost full marks

@blue You clearly have never gotten drunk and fallen asleep in a train station

user228700

6:26 AM

@JohnRennie Yes, of course. I was addressing the stereotype and maybe it sounded like I was sort of...adding to that, sorry.

Bernardo Meurer

That's real joy

Fawad

@BernardoMeurer yes,yes,I experienced

John Rennie

@Kaumudi.H I think the reserved Brit stereotype is largely an American invention.

Anonymous

@BernardoMeurer I don't drink in the first place =P

user228700

@JohnRennie Ohh, hmm, OK...

John Rennie

6:28 AM

Got to work for a few minutes - back soon ...

user228700

@blue You can't. Well, unless u live in one of those places where u can drink when you turn 18; do u live in Goa? :-P

Anonymous

@Kaumudi.H Some of my classmates used to drink even when they were just 14/15 ((They were mostly spoilt brats :-P)). No I don't live in Goa..

user228700

@JohnRennie Wokay but I have just received exciting information about a large batch of Gulab Jamuns being made because my family believes in astrology and today happens to be my star birthday and my mum is lovely and etc.

user228700

@blue I see.

Secret

[to be discussed later] Many worlds interpretation: Q3d: How does the universal wavefunction tell between an interaction that is a unitary evolution and a measurement (as only the latter will split the outcome into two worlds?)

Fawad

6:30 AM

@blue or @Kaumudi.H what is age limit for bhang people drink on holi?

Anonymous

@Fawad There's no age limit in India...lol :-P

Anonymous

You know the Indian laws, don't you?

Fawad

Know partially

Anonymous

Officially there might be

Anonymous

But who the hell follows laws here?

Fawad

6:32 AM

Lol

John Rennie

@Kaumudi.H Ooooooooooohhhhhh! Gulab Jamuns!! :-)

Secret

8

Q: Many-worlds: how often is the split how many are the universes? (And how do you model this mathematically.)

When I read descriptions of the many-worlds interpretation of quantum mechanics, they say things like "every possible outcome of every event defines or exists in its own history or world", but is this really accurate? This seems to imply that the universe only split at particular moments when "ev...

DanielSank

@BernardoMeurer <3

user228700

@JohnRennie :-D

Secret

ok fine, they have not thought about that question other than decoherence(except for the many interacting worlds camp)

user228700

6:35 AM

@Fawad TL; DR 21

Secret

Today's issue on newscientist covers Bohm stuff, vzn might be interested

Fawad

@Kaumudi.H OK,thanks

user228700

I'm not even going to attempt to drink it WHY DID I SPEND THE PAST 5 MINUTES GOOGLING THE CRAP OUT OF THIS?!

John Rennie

@Secret I thought the New Scientist article was a bit crap.

Fawad

@Kaumudi.H because I asked you.

user228700

6:38 AM

Sure sure, but I have confidence that you could've done the Googling yourself.

Secret

@JohnRennie I have not read it yet, but a breif skim seemed to cover that surreal trajectory article in 2012 or similar, thus there does nto seemed to be anything new

Fawad

@Kaumudi.H I prefer talking to real people than...

John Rennie

@Secret Yes. I think sometimes New Scientist have a few pages they need to fill so they dig into the gee whizz bucket to pull out one of a few stock topics.

user228700

I'm always a bit confused when people ask questions that are ridiculously easy to Google! Like what, do I give off the vibe that I possess some innate control over efficient search results?! I USE THE SAME GOOGLE AS U DO! (End of rant)

Anonymous

@Kaumudi.H They're just lazy. Like me.

Secret

6:41 AM

0

Q: In the many worlds interpretation of q.m. what makes a superposition af states split in two sepearate ones?

I was wondering, what agent makes a superposition of, let´s say, the two spins of an electron, máke them split into two separate ones (up and down). And is this not in contradiction to the law of conservation of energy? Or are all the states already there? But if all the states are already there,...

quantum-mechanics quantum-interpretations

MWI basically relabels the measurement problem instead of trying to solve it

Fawad

@Kaumudi.H Imagine you go on a site and you see "can't you just Google it?" Lol

user228700

YES but that is why "WHY DID I SPEND THE PAST 5 MINUTES GOOGLING THE CRAP OUT OF THIS?!".

Anonymous

@Kaumudi.H How is your prep going on?

user228700

@Fawad Huh? PEOPLE ARE NOT WEBSITES!

John Rennie

@Fawad We do sometimes tell people to go away and Google it

Fawad

6:43 AM

146

Q: How should we deal with Google questions?

I've seen a lot of questions that can be answered with a simple Google search. For these questions, an answer can be found by just cut'n'pasting the question directly into the Google search field and scanning the first few hits. Every new user wants to try out the feature and ask a question jus...

support faq

user228700

@blue It's going OK. How about yours?

Anonymous

@Kaumudi.H Same =P

Anonymous

I'm a bit scared after seeing so many 300+ scorers

Secret

http://physics.stackexchange.com/questions/11092/is-there-a-manifestly-lorentz-invariant-formulation-of-the-many-worlds-interpret

Ok fine, but you cannot just bury all that splitting into the hamiltonian, otherwise how are we suppose to know when and where decoherence occurs

user228700

@blue I'm not thinking about that.

Fawad

6:44 AM

How many you are getting in mains @blue @Kaumudi.H ? You also waited 1 year to writer mains again @blue ?

Anonymous

@Fawad In the 240-250 range. Results not out yet.

Anonymous

Second question's answer: No.

Secret

@Fawad Me being question banned 4 years ago due to 4 poorly received question (with one of them due to mislead by a crank youtube thing and get hastly downvoted and closed) is the main reason I pop up in this chat. Roughly a month later, the ban wore off, although I rarely had the need to ask questions in main until recently

Fawad

@Secret yes. I also will ask in chat now. Question ban is harsh

Secret

It should be noted that chat is not an excuse for bombarding volley of poor questions, though

(although I don't know how your questions are since they are the JEE stuff like most JEE people here, and I don't see a problem on that provided there is sufficient research)

Secret

6:50 AM

Meanwhile, in social psychology, there is an interesting study showing that we are relatively indifferent about inequality, but we are quite sensitive to unfairness, and this in current societies, combined with low social mobility, drives the complaint about social inequality

Fawad

@Secret I don't ask jee questions(till now),only theory questions(when I don't understand).

Thanks for advice

Secret

Key hightlights:

1. No evidence of people possessing aversion of inequality

2. There is evidence of aversion of unfairness (defined to be the amount of goods and resources should be distributed in a positively correlated manner to the merit and effort of the individual or group), which can lead to favoring inequality in some situations and rejecting inequality in others.

3. People generally underestimate the amount of inequality in the current society, and also underestimate the mobility in the current American market, thus viewing the US market as fairer than it actually is in wealth allocation

4. Inequality and fairness is often conflated. However more study is needed to invesitgate factors such as hard work, skill, need, morality) are psychologically relevant for fair distributions.

Secret

7:20 AM

@DanielSank The question I discussed with you previously about CHSH is refined here. Hopefully it is not too confusing

DanielSank

@Secret Why is there a quote box at the bottom of the question?

It's not quoting anything.

Secret

Uh, I recall many SE users tend to use that to highlight the question when the main post is unavoidably too verbose

(Many examples in CSE, MSE, PhiloSE, WSE etc.)

DanielSank

I would say the verboseness is quite avoidable.

I think this is an interesting question, but it's written poorly.

Secret

That's true. However, I am not so sure about concepts that arises from workings in a problem. Some of these are easy to highlight the concept, some of them not. In particular, I felt like the question will become unclear wif I only retain the lines cotaining the CHSH calculation

DanielSank

Define your notation!

I don't know what $|+\rangle$ means.

Secret

7:26 AM

Ok (fixing it now )

DanielSank

Most importantly, state the basis in which the matrices are expressed.

I think $\langle 11 \rangle$ is unclear.

Or at least, that's not really standard notation, is it?

Secret

Uh that one, susskind in his theoretical minimum book uses $\langle \sigma_x^A \sigma_x^B\rangle$ when talking about the expectation value of the joint correlation of two entangled spins in the x direction. I'll see if I can improve that by using the C(a,b) notation for correlation functions

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