The h Bar

yo

user218912

@Obliv I am learning about algebraic structures and group theory.

how come?

user218912

4:11 PM

I'm a math student now.

shakes head

user218912

@Obliv which book were you reading before?

user218912

dummit and foote?

yeah but it's more of an encyclopedia than a book for learning imo

i got up to lattice's of subgroups and then I just gave up because it got so boring.

user218912

I realized I need to learn advanced linear algebra first before abstract algebra, i.e. linear algebra with an abstract algebra approach.

user218912

4:13 PM

I found a good book for it

which?

I thought you already knew advanced linear algebra :O

wait what math is required for qft, then?

user218912

I know linear algebra :p

user218912

@Obliv multivariable/vector calculus, linear algebra, differential equations and integral transforms.

user218912

and some basic group theory.

user218912

this is for basic intro qft (1st year graduate/last year undergrad)

user218912

4:15 PM

@Obliv advanced linear algebra by loehr

@obe does it cover all of linear algebra, or does it assume basic knowledge/

user218912

@Obliv it assumes basic knowledge of abstract algebra which you have.

user218912

it covers all the linear part in detail

did you start learning it yet?

user218912

yes

user218912

4:18 PM

I am learning about groups, rings and fields in the first chapter which I barely ever learned before, and I am supplementing it with other books since it's just a review.

after i'm done with these exams i might try learning from this on the weekends or something then

user218912

nvm

@obe What do you think?

user218912

i'm retarded.

user218912

that's what I think

user218912

4:20 PM

:(

user218912

sorry

user218912

I thought 27 was prime???

lmao

don't worry @obe once I start learning it we'll be dumb together

user218912

@Obliv :D

user218912

4:47 PM

@Obliv ok so when will you be done? we can read the book together.

Q: What happens to comments which have been moved to chat?

@obe well I have my physics exam thursday. after that I'm free pretty much.

user218912

ok good luck

Physics Meta

0

What happens to comments which are moved to chat as times passes by? Are they conserved, or do they disappear after a time? This is triggered by the question Ground state of local parent Hamiltonians and invariance under local unitaries (which got bumped by the Community bot) -- I remember there...

support

this logic class is killing me slowly @obe imgur.com/a/KUTaK

.the more I scroll down the more of this I see. He linked a reading online to something called 'the cosmological argument' and it's just so cringe

user218912

lol it seems interesting though

5:03 PM

I think for non-stem majors, this type of class is really enlightening. But, it's kind of pointless for me because I already reason through things with logic. :( i hate mandatory classes

user116211

Hey @obe; what did you do?

user218912

@MAFIA36790 switch to math.

user116211

Great!

@Obliv If you think you don't need to learn the logic itself, then work on expressing it such that others can follow it instead. All the logic in the world won't help you if you can't communicate it to others.

4

user218912

@ACuriousMind applies to me as well :p

user116211

5:09 PM

So, what are you doing now @obe?

user218912

@MAFIA36790 learning analysis and abstract linear algebra.

user218912

analysis book: pugh, linear algebra book: loehr

To emphasize what @ACuriousMind mind said, I've always got a couple of students in my class who can solve problems competently but can't communicate worth squat. They are forever assuming context not shared, leaving out important adjectives, using the same pronoun to refer to several objects or people, employing a combination of sentence fragments and endless run-ons, and otherwise flailing around trying to get the thoughts from inside their heads transferred to other people.

user218912

i already know linear algebra just learning it in more advanced/proof form.

They are smart but it won't do them any good until they learn to communicate.

user116211

5:12 PM

okay. Hmm, I have no idea of these books.

Shameless plug: Writing good questions and answers on a Stack Exchange site is a way to practice those skills in a critical environment that won't adversely effect your long term prospects in the "real" world.

user218912

@MAFIA36790 check them out yo

user116211

I have Royden for analysis and Hofmann for Linear algebra; anyways, I'm currently into abstract algebra.

user218912

that's an old book :p

user116211

Hoffman is actually a very good book having some good (but few) problems.

user218912

5:20 PM

let me compare it to my book

user218912

looking at it now

user218912

@MAFIA36790 I think my book is better?

user218912

take a look at it

user116211

Maybe; but Hoffman and Kunze is working really well for me; it may not be advanced compared to yours, but it is really insightful for a novice like me.

user218912

I'm a novice too though :p

user218912

5:26 PM

i like this book

user218912

wait

user218912

@MAFIA36790 did you learn linear algebra before?

user116211

You are much more advanced than me.

user218912

nah lol

user116211

@obe yes; preliminary idea.

user116211

5:27 PM

no; rigorously.

user218912

@MAFIA36790 so like you have a working knowledge of linear algebra and can do basic "engineering" problems in linear algebra?

DanielSank

Bam

12

@MAFIA36790 o/

user116211

\o

@DanielSank Congrats! Are you sure that paper isn't a bit too obvious to be published, though? ;)

DanielSank

@ACuriousMind Well, you're right... it is rather obvious.

user116211

5:29 PM

I knew manipulations of matrices, row reduced forms, inverses, determinants, few of vector space, diagonalisation; but that's it.

user218912

@MAFIA36790 that's good enough.

user218912

another good book is linear algebra by roman but it seems a bit too advanced as a standalone book

Mike Miller

@DanielSank Pardon my ignorance. Is this quantum computing stuff?

DanielSank

@MikeMiller The physics discussed in the paper is not really quantum information, but the system under study is a superconducting qubit and its state measurement apparatus.

5:54 PM

@DanielSank PRL. Sweet.

vzn

7:26 PM

in theory salon, 1 min ago, by vzn

Veritasium launches soliton dynamics into 1M eternal viral living legend! / Tmachine blog

Sir Cumference

7:38 PM

@ACuriousMind You know what happened to 0celo?

bolbteppa

Anybody have a good interpretation for, way of remembering, the second one here: \begin{align}
\partial_j \mathbf{e}_i &= \mathbf{e}_{i,j} = \Gamma^k_{ij} \mathbf{e}_k \\
\partial_j \mathbf{e}^i &= \mathbf{e}^i_{,j} = - \Gamma^i_{kj} \mathbf{e}^k
\end{align}
can derive it, just don't like it

@0celo7 what are your thoughts on
\begin{align}
\partial_{\lambda} (\delta \Gamma^{\rho}_{\nu \mu} \mathbf{e}_{\rho} \otimes \mathbf{e}^{\nu} \otimes \mathbf{e}^{\mu}) &= (\partial_{\lambda} \delta \Gamma^{\rho}_{\nu \mu} ) \mathbf{e}_{\rho} \otimes \mathbf{e}^{\nu} \otimes \mathbf{e}^{\mu} + \delta \Gamma^{\rho}_{\nu \mu} ( \partial_{\lambda} \mathbf{e}_{\rho} ) \otimes \mathbf{e}^{\nu} \otimes \mathbf{e}^{\mu} \\
&+ \delta \Gamma^{\rho}_{\nu \mu} \mathbf{e}_{\rho} \otimes ( \partial_{\lambda} \mathbf{e}^{\nu} ) \otimes \mathbf{e}^{\mu} + \delta \Gamma^{\rho}_{\nu \mu} \mathbf{e}_{\rho}…

Sir Cumference

@obe This morning I was so tired I asked a friend if "stop" was spelled with an a or an o.

Pretty sure that's worse

Sanya

8:04 PM

@DanielSank nice :)

hey

important-ish: do any of you ever get scientific spam from legit physicists that talks about the Nobel Committee being a pseudoscientific cabal?

what I'm talking about tries to advertise the crackpot theories of a dude named Gabor Fekete, but you have to read a way into the bollocks to find this

8:21 PM

@AndrasDeak lol, Gabor Fekete is notorious for sending such spam

That you get that stuff from "legit physicists" either means you can't tell what a legit physicist is or that Gabor has discovered that email headers can lie :P

yes, that's why I'm asking

I find it hard that an idiot like that will make an effort to spoof a header, but I find it even harder to believe that legit physicists will compromise their servers

Yeah, I'm pretty sure that Gabor is spoofing headers

He's been at this thing for...more than a decade, I think

the real question is, don't you think that these alleged senders should be notified?

@ACuriousMind no way!

I've only encountered these e-mails recently (he did threaten suing me for "multiple acts of charlatanism" and the like, back in 2008 or something)

@AndrasDeak Here's a blog entry from 2009 where he pretendend his mails were sent by the APS.

So, yeah, nothing new on that front ;)

bah

I only found this blog when I started getting these, but that's much newer

The reason I'm non-trivially interested in him is that he's my countryman. I sort of feel responsible for him being an idiot:D Well, not responsible, but you know what I mean

But if this has been going on for a decade than there's really no point in informing alleged senders that their name is being abused. Last one I got had Haldane as sender...

8:45 PM

@AndrasDeak I think most of them have accepted Fekete's mails as a fact of life by now, like hurricanes, or the flu :P