The h Bar

ACuriousMind

00:00

@0celo7 It's two pages, I'll need longer to figure out whether you could possibly need this than you need to read it :P

0celo7

Unlike you I don't understand proofs instantly.

wtf is a dyadic rational number?

@ACuriousMind Are manifolds completely regular?

user54412

@0celo7 Meh. If I wrote a specialized book (say, on fluid dynamics in GR) and I only expected to sell a few thousand copies, and I only got 10% of the gross, and I needed to take a year off from work to write it, ...

ACuriousMind

@0celo7 I don't know what "completely regular" means

user54412

people complain about expensive books, but honestly the reason I don't intend to make a textbook is because I can't afford to do it

0celo7

@ACuriousMind T$_{3\frac{1}{2}}$?

ACuriousMind

00:08

@0celo7 lol, you don't seriously think I have any of the $T_i$-separation axioms memorized?

0celo7

Uh...I did

ACuriousMind

They rarely come up outside of intro and highly specialized topology

0celo7

@ACuriousMind def 9.5 on page 26 of Bredon then

@ChrisWhite hmm

ACuriousMind

@0celo7 Well, you can answer your question yourself. Is that a local or a global property?

(I.e. can it happen that this succeeds in a neighbourhood of $x$, but fails on the entire space?)

0celo7

what

ACuriousMind

00:12

The defining property of manifolds is that they're locally homeomorphic to the reals. So any local property that holds for the reals will also hold for manifolds

0celo7

I know

but I don't know if it fails or not

ACuriousMind

@0celo7 Say I give you the statement: For every $x\in X$ there is an open neighbourhood $U_x$ such that $U_x$ is completely regular. You should be able to prove that then $X$ is completely regular, too.

GPhys

@dmckee What do I need to know when picking a graduate school if I aim to be able to get postdoctoral positions after my PhD? What are the important factors?

ACuriousMind

@GPhys Shouldn't you have thought about that...before choosing where to apply? :P

GPhys

@ACuriousMind I'm talking about between schools I've been accepted to

0celo7

00:16

@ACuriousMind I have no idea

GPhys

As in, what should I look into when visiting, etc

0celo7

why do you assume I can do these PhD level proofs?

user54412

@GPhys The factor is where past graduates have ended up.

GPhys

@ChrisWhite ?

user54412

Where the graduates of the program have ended up tells you where you can end up. If they can't get the postdoc positions you want, you probably won't get them either. If they can, you probably will.

user54412

00:19

There's no other indicator that works so well.

user54412

I suppose it's possible that you go to a really outstanding program that opens the doors you want, but where nobody chooses that route.

user54412

In any event, the trick is getting an unbiased answer to what jobs people have gotten. In my experience departments have very selective memory. They'll tell you about so-and-so who is now tenured and doing well, but they'll forget about that guy that left the field in frustration.

0celo7

@ACuriousMind seriously, I don't see what you want me to do

user54412

You should ask the current grad students to list they're immediate predecessors, and give you hard numbers about how many went where.

0celo7

>they're

GPhys

00:23

I couldn't find anything online for Stony Brook for past students

user54412

Actually in general you should ask the current students tough questions. About everything. How happy are they? Do they regret their choice? Do they intend to keep working with their advisors once they leave? How many hours do they work?

user54412

@GPhys yeah, department websites will at best list a few examples of success stories

0celo7

@ACuriousMind Maybe $C$ can be taken to be the union of closed sets contained in the various $U_x$s?

ACuriousMind

@0celo7 Because it is quite straightforward: Let $C\subset X$ be closed, and $x\in X$. Then $C\cap U_x$ is closed in $U_x$ and since $U_x$ is completely regular, there is a function $f: U_x\to\mathbb{R}$ with $f(x)=0$ and $f(C\cap U_x) = 1$. Now just define $f(y) = 1$ for every $y\in X-U_x$ to extend $f$ to all of $X$. This is still continuous because the preimage of every open set that doesn't contain the 1 is unchanged and for those that contain the 1 their complement is unchanged.

0celo7

"Because it is quite straightforward"

I really don't know why you wold bother saying that

It's like authors that throw in "obviously" and "clearly" in various places

ACuriousMind

00:32

@0celo7 You literally take the function on the $U_x$ and glue a 1 on the rest to them, I don't know how much straighter the strategy could be

Hm, okay, there is a slight issue with the preimage of open sets that contain the 1

0celo7

Btw according to Wiki, manifolds are completely regular

FenderLesPaul

What it is?

mah peeps

ACuriousMind

@0celo7 That's what I was trying to get you to show :P

0celo7

Well I can't do PhD level topology!

And I don't see why your new $f$ is continuous

FenderLesPaul

@ChrisWhite But that means working for Bob Wald is a bad idea :(

since most of his past grad students haven't ended up in permanent GR research positions or even physics academia in general

user54412

00:36

@FenderLesPaul Do his students not do well?

FenderLesPaul

I think only one of them has in fact

Sam Gralla

he got a tenure track at Arizona

all the other ones I've seen are either in industry or do random things in math

user54412

well, the majority of my adviser's students are not in academia at all -- not sure you'll ever have high numbers there

user54412

it's not about absolute numbers, but comparisons between what options you have

FenderLesPaul

oh I misunderstood what you meant

plus my example was probably bad

user54412

also, what matters most is where they end up with their first position afterward

FenderLesPaul

00:38

since even if your advisor is Bob fucking Wald, there are next to zero post-doc and faculty positions for pure/classical GR research (theoretical, not numerical or astrophysics)

it's basically a dead field

0celo7

GR is pretty worthless.

user54412

::waits for ACM to post chat log about trolling::

0celo7

Who's trolling?

user54412

@FenderLesPaul saw that edit

user54412

it's okay, I have a job already

0celo7

00:39

@ChrisWhite Well maybe I would change my mind if my adviser didn't tell me to get a fucking $300 GR book

@ChrisWhite you got a postdoc position?

FenderLesPaul

@ChrisWhite yeah sorry I meant like Bob Wald type research

user54412

yes in fact :)

FenderLesPaul

Congrats!!!

0celo7

@FenderLesPaul Go into pure math, do geometry

FenderLesPaul

@0celo7 I'll pass thanks

@ChrisWhite in fact do you remember David Nichols?

0celo7

00:41

@ChrisWhite where

FenderLesPaul

He applied for post-docs this year as well for theoretical GR

and he's had a really rough time

user54412

@FenderLesPaul yeah -- my TA for a few courses

FenderLesPaul

I think his best option is Penn State with Ashtekar

but that involves taking a foray into LQG which he isn't too keen on

so yeah theoretical GR is probably not the best example since it's an almost dead field

user54412

@0celo7 joint offer by Berkeley and Santa Barbara

FenderLesPaul

@ChrisWhite does your post-doc area involve warm weather? :)

OMGGG

Duude we can bro out!

:)

user54412

00:43

:)

FenderLesPaul

so how does a joint offer work?

user54412

the first 1.5 years up north, with visits to KITP, and then I reverse for the next 1.5 years

user54412

at least that's the plan

FenderLesPaul

Wait which one is more north?

user54412

we'll see how it plays out

user54412

00:45

@FenderLesPaul wow you really are east coast

0celo7

@ACuriousMind What the heck is a sequence that is dense in a space

FenderLesPaul

@ChrisWhite :p

0celo7

@ChrisWhite I don't know either, but I'm also not sure if NYC is above Boston or not.

ACuriousMind

@0celo7 The rationals in the reals.

FenderLesPaul

Oh Berkeley is more north

user54412

00:46

I bet ACM knows US geography

0celo7

@ACuriousMind no, I mean the definition

FenderLesPaul

aww that means I won't see you until 1.5 years later?

0celo7

no

FenderLesPaul

Oh but you have visits to KITP

yay

0celo7

I know what the definition is

user54412

00:46

yeah

0celo7

@ACuriousMind If $X$ is totally bounded, why can we find a sequence $(x_n)$ that is dense in $X$.

FenderLesPaul

Sweet

0celo7

There we go

@ChrisWhite I don't know German geography either

FenderLesPaul

@ChrisWhite are you going to be at KITP anytime soon?

ACuriousMind

@ChrisWhite I'd not be willing to take an exam on it :P

user54412

00:48

@FenderLesPaul probably not before sep/oct at the earliest

FenderLesPaul

Ok cool

So I'll see you before the end of the year at least

:)

user54412

by the end of the year I intend to have met 3-4 people from this chat in person

ACuriousMind

@0celo7 Just take the sequence that consists first of all the centers of an $\epsilon=1$-cover, then of the centers of an $1/2$-cover, then of the centers of an $1/3$-cover...

user54412

also, KITP mentioned in their offer that they have funds to travel especially to MPA-Garching, so...

0celo7

@ACuriousMind Proof by contradiction to show that all points appear in the sequence?

ACuriousMind

00:53

@0celo7 "dense" does not mean that "all points appear".

skully

I don't know if this question is worth posting as a question on the site

Is it okay if I ask physics questions in the chatroom?

Or is it better off if I just post a homework question on the site?

0celo7

Only topology is allowed in here

skully

Okay, no dank memes?

0celo7

@skully That's not allowed

ACuriousMind

@skully Unless you have read our homework policy and made sure your question is not off-topic, don't post it on the site

skully

00:54

Oh :(

0celo7

@ACuriousMind What does it mean

ACuriousMind

@0celo7 I thought you knew the definition?

A dense set is one whose closure is the entire space.

0celo7

@ACuriousMind Well I have no clue how to define $\operatorname{cl}(x_n)=X$

specifically the LHS

I have no clue what it means

ACuriousMind

@0celo7 You're in a metric space.

0celo7

So I take the limit, right

ACuriousMind

00:55

wat

The limit would be a point, if it exists

0celo7

Yes

Ok so $(x_n)=X-\lim x_n$?

ACuriousMind

You want the closure. The closure are all points which are infinitesimally close to the set.

@0celo7 No

That is, the closure consists of every point that is either in the sequence or for which there is a subsequence converging to it

0celo7

Yes, of course.

ACuriousMind

By making a sequence that consists of the centers of continually shrinking balls, it is ensured that for every point in the space, there is such a subsequence

0celo7

Ok...so how is the sequence you defined dense in $X$?

What

This should be obvious, he does not prove it

This is not obvious

GPhys

00:59

@ACuriousMind certainly the first condition was not necessary :P

user54412

@skully which means you can ask things in chat, but while someone might be willing to help with homework, no one here is interested in just doing it

ACuriousMind

@0celo7 For every $x\in X$, and every $n\in \mathbb{N}$, there is a ball of radius $1/n$ such that $x$ is inside it. The sequence of the centers of those balls obviously converges to $x$, and the sequence I built contains every such sequence for every $x$.

0celo7

I would challenge the "obviously" line

ACuriousMind

@GPhys Huh? $x_n= 1/n$ has no subsequence converging to $1/3$, for instance.

0celo7

But we've been down that road before, you like using words like that

ACuriousMind

01:00

@0celo7 Those centers get arbitrarily close to $x$, that's exactly the definition of convergence.

GPhys

@ACuriousMind is your metric you are finding the closure of the union of those?

0celo7

@ACuriousMind seems pretty sketchy

ACuriousMind

@0celo7 The "obviously" is has a dual meaning: It means both "I will not bother writing this out." and "If you do not think this is obvious, think about it until you agree".

@GPhys I cannot parse that sentence. Please rephrase.

0celo7

I agree, but I don't know how to justify that I agree.

GPhys

@ACuriousMind :27544080 I was intending to respond to what I read was a claim about the nature of the points in the closure of set. I do not understand how your response dealt with this, so I am asking for clarification.

dmckee

01:05

@GPhys Chris' remarks are extremely pertinent. The more so as they represent a factual question rather than one of simple opinion.

That said the data could be hard to come by.

0celo7

@ACuriousMind I will try to come up with a proof of your statement for $\mathbb{R}$...

It's not "obvious"

ACuriousMind

@GPhys I had two conditions: 1. The point is in the sequence. 2. The sequence has a subsequence converging to it. You claimed the first was not necessary, I countered your claim by exhibiting a sequence which has points to which no subsequence converges.

0celo7

::pulls earplug out of pocket::

What

@ACuriousMind Pretty sure I'm going insane.

ACuriousMind

Hmmmm...or are you people using "sequence" also for finite ordered tupels?

GPhys

@ACuriousMind Yeah I don't understand at all. What are you defining with this? It absolutely does not appear to be what I thought I was responding to, still

0celo7

01:11

@ACuriousMind A sequence is $f:\mathbb{N}\to X$.

ACuriousMind

@GPhys Those two conditions define the points that lie in the closure of the sequence (viewed as a set)

0celo7

And a subsequence is $a_{n_j}$, $j\in\mathbb{N}$ where $n_{j}<n_{j+1}$

@ACuriousMind That's how we defined it in analysis class, anyway

ACuriousMind

@0celo7 Yes, that's how I see it, too

@GPhys It uses the characterization of a closed set as being sequentially closed, I'm not sure where we are misunderstanding each other

0celo7

@ACuriousMind the prof said a billion times that the inequality there is strict

@ACuriousMind The claim is that if $x_n$ is the center of the $1/n$-ball containing $x$, then $\lim x_n=x $?

That's obvious

ACuriousMind

@0celo7 Yes

@0celo7 Yes.

0celo7

01:19

Don't know how to prove it though

Don't prove it!

I know you love proving analysis things for me, control yourself

GPhys

@ACuriousMind It certainly was partially unclear to describe the set itself as a sequence: however, that was what my first question was intending to ask: if your set you're finding the closure of was intended to be the union of the points in the sequence you gave (the answer: yes). I interpreted your second condition as being the set of points that have a sequence in the set converging to it. And, of course, for metric spaces this is exactly the closure without needing to include the first condition

ACuriousMind

@GPhys Ah, right. I see that could have been clearer.

GPhys

I was certain something was misunderstood (by me or both), I was just a little confused what

Anyway, I'm headed off

time to go fret graduate school choices

FenderLesPaul

@GPhys bye!

0celo7

@ACuriousMind Do I need to do induction for this proof?

ACuriousMind

01:28

@0celo7 No, not that I can see

0celo7

@ACuriousMind I'm having trouble with the $\forall n\ge N$ part, then.

It's clear that the balls have to be nested, but I think I need an induction to prove that.

ACuriousMind

@0celo7 No. $n\geq N$ implies $1/n\leq 1/N$.

And the balls are not necessarily "nested"

0celo7

Actually, they're not nested.

@ACuriousMind uhhhhh

let me think

0celo7

01:45

@ACuriousMind Ah!

It's trivial

Just needed some food to clear my mind :)

@ACuriousMind Just pick $N\ge 1/\epsilon$ and everything works out.

ACuriousMind

Aye

0celo7

@ACuriousMind I was focusing on them having to be nested, which was wrong.

@ACuriousMind Oh god in PDE we're going to do wave equations with time-dependent boundary conditions D:

I can imagine the number of Fourier series in the solution doubling

vzn

02:14

gravity wave breakthrough, einstein strikes again! / TMachine blog

0celo7

02:43

@ChrisWhite Do you own Hawking-Ellis?

@ChrisWhite Alternatively, what do you know about Bianchi I spaces?

user54412

no and I never could keep track of that crazy classification scheme

user54412

it's like the separation axioms

0celo7

No?

What GR books DO you own

Carroll, Wald, MTW?

user54412

of course

0celo7

"Of course"

Carroll and MTW are too expensive.

user54412

02:50

probably a few lower level ones too

0celo7

Why?

user54412

is HE even a textbook?

0celo7

Serious question

@ChrisWhite Nope

It's a "monograph"

user54412

I only really own textbooks that were used in a class, and a couple reference books of the kind I can actually cite in a publication

0celo7

You don't think HE can be cited in a publication?

user54412

02:53

let me rephrase -- something I can and will cite in some publication

0celo7

Ah

user54412

nothing I do is at the level of HE

0celo7

Damn chap 7

@ChrisWhite What book did you learn PDEs from?

not numerical

I want to reread HE, this time proving everything properly, but chap 7 on the Cauchy problem scares me

user54412

@0celo7 none, my PDE class didn't even pretend to use a book

0celo7

I'm stuck

I despise analysis and topology

Can't do much without them, though

user54412

02:57

also, in hindsight I'm not sure how much there actually is to non-numerical PDEs

0celo7

Sobolev inequalities

...that might be it

ask @yuggib, I think that's his field :P

user54412

I mean, there's the standard couple of tricks for turning them into ODEs, and there's the 3 special cases for 2nd order linear systems, and I can't remember anything else

0celo7

well somehow one has to prove that the EFE can be solved

otherwise your field would be wrong

user54412

yeah, those 3 cases are where you get a degeneracy where the Cauchy problem isn't trivially solvable

0celo7

what are you talking about

user54412

03:00

I feel like you could write a book on the details, but ultimately 2nd order linear PDEs don't do anything you don't expect

0celo7

The EFE are nonlinear...

Choquet-Bruhat wrote a whole book on the Cauchy problem in GR from an analytical perspective

user54412

@0celo7 leading terms are linear -- close enough

0celo7

so the Cauchy problem has pretty much been figured out?

user54412

basically

0celo7

no, for GR

user54412

03:06

I mean, I count local existence as sufficient

0celo7

local existence does not care about topology, which is the interesting part

user54412

also the impossibly hard part

0celo7

hmm, there seems to be a correlation between impossibly hard and interesting...

Secret

03:22

@ACuriousMind I tend to end up having too much quantum stuff whenever I think about GR and always forgot it is 100% classical

@0celo7 For me, impossibly hard=alien=novel=interesting=new territories

gansub

if I had a cube shaped planet gravity would not operate ?

only spherical planets have gravity?

Secret

Some of my professor in my chemistry department kinda foreshadow this as they talked about the problem of the "pay to open access" system

sciencealert.com/…

gansub

@Secret - I guess you do not know the answer to my question

hence the attempt to digress

Secret

I am not digressing, I am talking to the other users that will be on 13 hours later.

For this case, I actually don't know the answer

0celo7 might be a better guy as he studies GR

gansub

curvature is the cause of gravity right @Secret ?

so if the curvature is removed what happens to gravity ?

adios ?

0celo7

03:30

@gansub what are you talking about

gansub

doesnt GR say gravity is due to curvature ?

so if the curvature of the planet is removed then ?

0celo7

What?

gansub

i dunno you tell me

0celo7

How do you remove the curvature?

gansub

it is just a gedanken experiment bro

0celo7

03:32

Physics can't tell you about unphysical situations

gansub

oh

Secret

The curvature is the curvature of spacetime, not the curvature of the shape of the planet. As long the planet has a nonzero stress energy tensor, it should be able to bend spacetime and hence giving the effects of gravity

though it would not be a simple $1/r^2$ like potential due to its cubic shape

gansub

ok big difference

thanks for clarifying my doubts

0celo7

> not the curvature of the shape of the planet.

what

Why would it be that curvature?

gansub

if i understand GR right space time is curved only because of astronomical bodies am i correct?

0celo7

03:36

@gansub You understand it wrong

gansub

ok then enlighten me

0celo7

Spacetime is curved by nonzero energy/momentum/mass

This means pretty much anything curves spacetime

gansub

so is empty space - where there is nothing is that curved as well?

0celo7

Sorry, what?

gansub

say a location outside the solar system where there is "nothing"

no mass whatsoever

is that curved ?

0celo7

03:38

Yes

Because in the solar system there is matter

gansub

i said a point in space where there is no matter whatsoever

0celo7

Spacetime will be curved if there is matter anywhere in the universe

gansub

hmmmm

so the effects of matter are field like ?

0celo7

Just like we can have an electrical field far away from the source

gansub

so the spacetime curvature is felt like a field ?

far away from it's source ?

0celo7

03:40

Yes!

gansub

what about at the beginning

of time

0celo7

GR can't tell us about the beginning, only what happened after it

gansub

so immediately after the beginning spacetime becomes curved ?

0celo7

@gansub well...I'm not sure if "spacetime" is even the right word for stuff before the beginning

gansub

what i am saying is just after the beginning

say when hydrogen atoms form

by that time is spacetime curved

0celo7

03:46

ok, spacetime was always curved

look up the FLRW metric

we believe that the "background" spacetime is curved by default

but I'm not up to snuff on my big bang phenomenology

gansub

ok thanks you made me understand some hard concepts

Secret

04:42

nasa.gov/feature/jpl/…

link.springer.com/article/10.1140/epjc/…

smbc-comics.com/index.php?id=1309

user116211

05:52

@Qmechanic: Good to see you back! PSE without you is like the cold winter; Spring came back ;D

Valentin Tihomirov

10:40

Hi, web.pdx.edu/~pmoeck/pdf/Mermin%20short.pdf says that we can build an impossible device using famous Bohm's setup in the appendix. I see something about couple of detectors rotated by angles various angles and formula $sin^2(\theta/2)$, which looks similar to Mermin's $cos^2(\theta/2)$ but it is too hardcore for me in Harris. I do not not have a clue. Is there explanation for mortals, starting from how do you detect spins?

Is there a variation of the experiment with simple light polarization which can explain everything in electrodynamics?

Slereah

12:13

@0celo7 Maybe the omega comes from THE ALPHA AND THE OMEGA

(PRAISE THE LORD)

Secret

heh

Slereah

You know I'm not quite sure what would be the metric of a cubic distribution in spacetime

not sure it's been done

Secret

http://chat.stackexchange.com/transcript/message/27549980#27549980
this stuff reminds of entanglement but I think I still have not fully understood the maths of qunautm mechanics to investigate this further

Thus right now, besdies writing my molecular laser photochemsitry thesis, I am reading this

https://en.wikipedia.org/wiki/Mathematical_formulation_of_quantum_mechanics

Slereah

The problem being that a cube basically has no continuous symmetries

Secret

@Slereah Well, it can in princple be modelled, but I don't think there's an analytical expression for it. IT has to be doen numerically

Slereah

12:18

Oh you never know

Plenty of weird spacetimes have been done anaytically

But one with no symmetries (outside of time), not sure

It's probably doable in the thin shell limit

I remember that Visser did cubical wormholes

Secret

$$|\Psi\rangle=\sum_i|A_i\rangle\otimes|B_i\rangle$$
$$ \hat{M}|\Psi\rangle=\hat{M}\left(\sum_i|A_i\rangle\otimes|B_i\rangle \right)$$

To be continued...

@Slereah Why would cubic wormholes be interesting?

Slereah

Because a wormhole with flat faces has no tidal forces

Secret

makes sense

Slereah

Well, the tidal forces are concentrated on the edges

don't bump your head on the edge

Although really a cubical wormhole has pretty unrealistic sources

Secret

(To prevent anyone from asking WTF is that): some attempt at modelling a general entanglement system and then measured it using $\hat{M}$. The aim is to see how computing this thing shows how the entangled states changed by the measurement operator

However I need to revise how t do tesnro procdtucts

ACuriousMind

15:30

Man, gravitational wave questions really are drowning out everything except the ever-persistent homework questions :P

Also, Skeptics is being really skeptical:

60

Q: Do researchers receive no income from revenues arising from their published papers?

According to this article Meet the Robin Hood of Science (about the creator of a website to bypass paper access restrictions and paywalls), Elbakyan made a point that will likely come as a shock to many outside the academic community: Researchers and universities don’t earn a single penny...

scientific-papers

I mean...that's not really a question about "scientific skepticism" is it?

0celo7

@ACuriousMind I can remedy that with some topology questions :)

Slereah

I'd ask a question but nobody ever answers my questions :p

ACuriousMind

@Slereah Yeah, that happens :/

Sidarth

15:51

hello

@Slereah lets hear it

Slereah

Well I have a bunch of unanswered questions if you want

Although for some I found the answer later on

Sidarth

was it interesting?

Slereah

Well physics is always interesting :p

Sidarth

I concur

:P

give us one question

Slereah

The one I found an answer for btw is that the chronology protection conjecture cannot be circumvented by a spacetime with non-geodesic CTCs because those are always present in the Cauchy horizon

2

Q: How to deal with boundary conditions for path integrals?

For non-relativistic quantum mechanics, the boundary conditions are rather simple to deal with, they are just \begin{equation} \langle x_1, t_1 \vert x_2, t_2\rangle = \int_{x_1(t_1)}^{x_2(t_2)} \mathcal{D}x(t)e^{\frac{i}{\hbar}S[x(t)]} \end{equation} And then we can solve the path integral by...

quantum-field-theory path-integral boundary-conditions

This one still doesn't have any satisfying answers, too

6

Q: Homotopy proof of the lack of foliation of the Gödel metric

A common proof of the lack of foliation of the Gödel universe, apparently mostly copy pasted from Hawking and Ellis, goes thusly : A closed timelike curve must cross a spacelike hypersurface without boundary an odd number of times A continuous deformation of the curve can only change the numbe...

general-relativity differential-geometry topology closed-timelike-curve

Sorry Timaeus

0celo7

15:56

@ACuriousMind Holy crap that $300 book treats Morse functions on Lorentzian manifolds :o

Sidarth

gimme a sec ....

Slereah

also

2

Q: Full form of the Pauli-Fierz action

In Deser's paper on the fully interacting version of the Pauli Fierz theory, he does a rather simple method of treating the Pauli Fierz equation without going with infinite sums, just by treating the metric and the connection separately, hiding the infinite sum in the dynamics linking the (invers...

general-relativity field-theory

Sidarth

@Slereah

Slereah

-4

Q: What will a true law of gravitation look like?

Newton's law of gravitation and Einstein's general relativity (GR) are empirical laws of gravitation that are strong on description and prediction but lack deterministic and/or causal rigor, which makes both of them incompatible with the fundamental laws of physical reality. Newton's action-at-d...

general-relativity gravity newtonian-gravity soft-question quantum-gravity

lawl

Sidarth

@ACuriousMind.....what do you make of @Slereah 's questions?

they're complex!

ACuriousMind

15:59

I know

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