The h Bar

@DanielSank: Can you recommend me some good introductory solid state physics book; I remember you told me once not to get Kittel's Solid State Physics.....can you recommend me some good introductory one?

Slereah

10:23 AM

Kittel

Oh, not kittel was recommended

I don't know then

0celo7

@Slereah Penrose and Visser are on the way

Slereah

Aight

0celo7

I took @ACuriousMind 's advice and am not getting Steenrod, I'd only need it for one proof.

Slereah

I like that I opened Steenrod at the page of that proof so often that it naturally opens to that page

0celo7

Do you understand it?

Slereah

10:28 AM

No

0celo7

lel

Slereah

I am missing some of the stuff in between :p

0celo7

What will I learn from Visser

Will I learn why there are no wormholes

Maybe we should do a group reading with @JohnDuffield

@FenderLesPaul I saw that snap as I was waking up, accidentally clicked it off, no clue what it was.

Slereah

10:52 AM

Visser is like

History of the concept of wormholes

Topology business in GR

Examples using the Morris Thorne wormhole

Thin shell wormholes

CTCs using wormholes

Quantum effects on CTCs

Energy conditions

stuff like that

user116211

@Slereah huh?

Slereah

Well I recommended kittel

user116211

oh.

Slereah

Then I read

"I remember you told me once not to get Kittel's Solid State Physics."

so i dunno

user116211

get it.

user116211

10:55 AM

@Slereah: Have you read Manchester Physics Series?

Slereah

I have not

Frankly I'm not big in solid state physics

I only use Kittel because that is what we did in school

user116211

@Slereah: I once read Kittel's Statistical Mechanics but it was not as good as Reif's.

ACuriousMind

@NeuroFuzzy 'kay

Slereah

I should do that idea I got once

Linearized gravity solid state physics

I am wondering what it would be like

0celo7

11:11 AM

How would you even begin to go about that

@ACuriousMind going back to school, left Steiner at home

Slereah

Find the SET of a solid

Calculate linearized metric

0celo7

Is that a Green's function thing?

Slereah

Well you calculate the metric with a source with a green function, yes

0celo7

11:26 AM

@Slereah Now Amazon is recommending actual crackpot books

Slereah

Ahahah

Which!

0celo7

"The physics of stargates"

Slereah

I've got that one

The cover is hilarious

It's... not actually too bad?

I wouldn't recommend it as a physics book

It's written for normies and all

But

It has a very good bibliographical section

Lots of interesting paper references

0celo7

Does Rovelli treat the Hamiltonian theory really extensively?

ADM and all that stuff?

Slereah

Well it's not the focus but he does a chapter on hamiltonian theory in general, and another chapter on ADM

The book is freely available online, if you wanna check

0celo7

11:30 AM

I'm sure I have a legal copy already. But unless the GR is really good, I don't think I need it.

Slereah

Then maybe not I guess

After chapter 6 it's all quantum gravity

0celo7

There was some other quantum gravity book that had a lot of GR in it

Was like 700 pages

Huh cambridge.org/US/academic/subjects/astronomy/astrophysics/…

Slereah

Most QG books have interesting GR bits in them

0celo7

cambridge.org/US/academic/subjects/physics/…

I think that's the one

Hmm. I can't find the table of contents

FenderLesPaul

11:59 AM

@0celo7 yeah sorry about that dude

I was insanely drunk

and accidentally sent it to you

it was a friend of mine eating leaves

@NeuroFuzzy quantum gravity

mainly gauge/gravity duality and semi-classical gravity (black hole thermodynamics)

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Celebrating?

FenderLesPaul

Nah celebration ended like a month ago

It was a marching band rooms party

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

I see...

Have you @0celo7 decided on a name?

I still can't understand why you rejected "cruiser."

FenderLesPaul

Holy shit Zee has a new book coming out

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

:O when?

FenderLesPaul

12:11 PM

end of the month

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Why did you ~~Chicago~~?

after the visit

After all, it is closer to home...

FenderLesPaul

I actually didn't want to be close to home

I wanted to step away from home as much as possible

and as far as Chicago goes

I really, really loved talking to Bob Wald

that was easily the highlight of the trip

but I tried scoping out the nature of practice of the high energy theory group there and their general research interests

and it's all like pure string theory stuff which I don't care for in the slightest

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

I see.

FenderLesPaul

there's no one there doing quantum gravity along the lines of what Polchinski, Susskind, Strominger, Bousso etc.

which is where my interests lie

so I felt at Chicago I would be pigeonholed into one narrow area of research

i.e. classical or semi-classical GR (which, granted, I love)

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Did you talk to Wald about this?

FenderLesPaul

12:22 PM

Unfortunately not

they gave us a limited amount of time to talk to each professor of interest

only like 25 mins

and all of that time with Wald was spent talking about physics

specifically firewall/AMPS paradox and soft black hole hair

also I didn't know how to broach such a subject with him without sounding potentially offensive

I talked about it with my advisors though

they said UCSB or Berkeley is probably a much better choice than MIT or Chicago

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Are your advisors into research too?

FenderLesPaul

oh yeah these are my research advisors

one of them did their postdoc at UCSB before coming to Cornell as a professor actually

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Interesting

0celo7

Dunno where my advisors would want me to go

@FenderLesPaul Just so you know, I've given up waiting for those solutions

FenderLesPaul

I'm sorryyyy I've just been lazy

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

12:35 PM

It should really depend on how much you value their advice.

Or anyone's advice...

...as they say the price of wisdom is experience.

FenderLesPaul

I do value their wisdom though

they know the nature of academia much much much better than I do

0celo7

Don't be silly

You know more than them

FenderLesPaul

:P

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Know thy self.

0celo7

They're old, probably have Alzheimer's

FenderLesPaul

12:44 PM

one of them is like 34 though :/

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

:-/

0celo7

12:56 PM

@FenderLesPaul What's the record?

27, according to Google.

Going back to school, will finally have Springer/journal access again

FenderLesPaul

what record?

0celo7

Record for youngest case of Alz

FenderLesPaul

ohhh

damn 27

0celo7

I think it was a person with Down's snydrome though

Slereah

Upside down syndrome

hubot

1:12 PM

Is there anyone?

Slereah

no

FenderLesPaul

woo

I finally learned Landslide

0celo7

@FenderLesPaul Do you know how to prove that causal relations are transitive

It's an exercise in Wald, but I'm not convinced one can do it with the tools he provides

FenderLesPaul

I don't off the top of my head unfortunately

what problem though?

0celo7

8.1 AFAIK.

The problem is that the concatenation of smooth timelike curves need not be smooth.

And causal relations are defined with smooth curves.

FenderLesPaul

1:25 PM

concatenation?

0celo7

Union

FenderLesPaul

oh

Ok let me check it out after I shower

0celo7

The "real" proof is given in Penrose (1972), but Wald and HE don't contain it AFAIK.

You have to do some crazy smoothing procedure.

FenderLesPaul

oh shit I remember looking that up too

yeah now I remember

dude that proof is insanely non-trivial

0celo7

I ordered Penrose because I want to know the proof.

I'm doing a reading course on diff topology this summer with my advisor. I'll ask him if we can cover that.

FenderLesPaul

1:40 PM

cool

you doing research over summer too?

0celo7

2:05 PM

Yes

DanielSank

2:16 PM

@user36790 I've only used two books, Kittel and Ashcroft & Mermin.

The latter is better.

@FenderLesPaul know where you're going to grad school?

user116211

2:34 PM

@DanielSank Thanks for the recommendation :)

user116211

Oh....this is way much cheaper than Kittel's.

hubot

Should I solve all exercises on Resnick & Halliday's book or can I solve only some exercises?

user116211

@hubot I don't think there is any harm to solve it.

0celo7

2:50 PM

@Slereah Umm, HE doesn't use everywhere smooth curves, they use piecewise diff curves.

Then everything becomes trivial!

Slereah

if it's piecewise, yeah

0celo7

@Slereah Check out Prop 4.5.10 in HE.

0celo7

3:26 PM

@Slereah Do you understand the proof?

I think I need to reread chap 4

Holy shit HE has terrible notation

FenderLesPaul

4:56 PM

@DanielSank not yet

still deciding between UCSB and Berkeley

I'll see you soon though if you're around for visit day!

0celo7

@ACuriousMind Yup, I hate HE.

Worst book.

0celo7

5:38 PM

Why is the chat dead today?

0celo7

5:53 PM

My god, H&E are geniuses.

DanielSank

6:21 PM

@FenderLesPaul When's that?

@FenderLesPaul Wait I forget... are you going for grad or undergrad?

0celo7

@DanielSank grad, of course

skill patrol

is the tennessee border dispute still going on?

0celo7

What?

skill patrol

georgia and tennessee were fighting about their border

didn't you hear?

0celo7

No

skill patrol

6:35 PM

timesfreepress.com/news/local/story/2014/feb/18/…

ACuriousMind

-1

Q: I screwed up horribly

While messing around with the laws of physics, I accidentally caused the entire planet to gain a net positive charge of five. What have I done, what are the consequences, and how do I fix it. Any suggestion? I won't risk playing around with the laws of Physics anymore, so if someone has a 'possib...

wat

skill patrol

lol

0celo7

+1 for effort

ACuriousMind

@0celo7 Don't upvote garbage.

0celo7

Yes ma'am

DanielSank

6:41 PM

@ACuriousMind Came here to post that.

I love the tags.

We need a hall of fame and this should be on it.

HDE 226868

@ACuriousMind I can't wait to hear the creative close reasons.

ACuriousMind

@HDE226868 ...someone already voted to close as homework-like oO

HDE 226868

facepalm

skill patrol

O.o

0celo7

That was me.

Didn't know what else to VTC as!

Maybe it's a writing prompt for his creative writing class.

ACuriousMind

6:45 PM

unclear what you asking? Or a custom close reason?

0celo7

Didn't even think of that.

Too late now!

@ACuriousMind I voted on the answer as "not an answer"

ACuriousMind

Not a vote, but a flag, but al least that one's correct ;P

0celo7

Whatever.

HE has scrambled my brains

skill patrol

7 hours ago, by Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Have you @0celo7 decided on a name?

what's wrong with "cruiser"?

0celo7

Not very imaginative

And it should be physics/math related

Like "the parallel transporter"

ACuriousMind

6:57 PM

That sounds like it should be the name of a van

skill patrol

sounds "treky" to me

0celo7

i think there's a typo in HE

But I don't want to do the calculation to verify it.

Oh the life of a lazy student

0celo7

7:33 PM

Ah. Not a typo.

skill patrol

you did the calc?

0celo7

Yes, took two pages.

Wow this is a nontrivial theorem if I've ever seen one!

I'm just a little confused by why they did everything the way they did, but hey

skill patrol

20 hours ago, by ACuriousMind

At some point in your life, you need to learn to take theorems as black boxes.

0celo7

@skillpatrol I understand the concept of the proof

But they create this vector that I think could be simpler

I mean, the idea behind the proof is brilliant.

@ACuriousMind Suppose I have some curve where the tangent vector is discontinuous. If, at the point of discontinuity the discontinuity is just a scaling, can I adjust the curve parameter so there's no discontinuity anymore?

Like if before the discontinuity, th tangent vector is V, but right after, it's 5V

The components aren't technically continuous, but the direction is

FenderLesPaul

8:14 PM

@DanielSank grad school

and it's on the 7th and 8th of April

right after Berkeley

0celo7

@FenderLesPaul do you happen to understand Prop. 4.5.10 in HE

Damn, it's not the thing I need.

@skillpatrol lol, spent a good part of this day understanding a handful of theorems and proofs and now I realize it's not what I need.

Physics Meta

0

Q: Using Copyrighted Material as Answers

How do I use pictures and copyrighted stuff as material. If you can quote someone why can you not quote their work as well? The teacher said in your own words. Does that fix the problem? Does that mean have to redraw a picture or find one not copyrighted?

discussion support answers formatting

skill patrol

@0celo7 live and learn

DanielSank

@ChrisWhite suppose I have calculated a functional form for a pdf of some data.

Then on my computer I generate a bunch of data which should be distributed according to that pdf.

How do I write a test function which answers the question "Are these numerically generated random data in agreement with the pdf function I calculated?"?

0celo7

8:39 PM

@Slereah Why exactly do the curves need to be C^1 everywhere? What's wrong with them being piecewise?

As long as they're continuous and at the corners the tangent vectors point into the same half of the light cone, I see no issue.

0celo7

9:38 PM

@Slereah Why do the open sets $I^+(p)$ form an open cover? What guarantees some point is in the future of another?

Ah, I think geodesics are defined on open intervals on a boundaryless manifold.

0celo7

11:35 PM

@dmckee Is your spring break over tomorrow?