/sci/ - Science & Math

google

to begin must start at with school

>>4368354
reported for pony trolling

>>4368354
reported.

>>4368351
>>4368354

what the heck is going on in this thread.

>>4368370
reported for pony trolling

>>4368370
enjoy the ban

>>4368361
enjoy the ban

>>4368370
Reported.

>>4368349

Start with QFT.
Weinberg, Peskin/Schroeder, Bjorken/Drell have some books.

I'm bored, let's talk about some QFT...

>>4368396
How about no you can fuck off too redhead fag reported

>>4368396
Ok...what in particular do you want to talk about?

Do you know QFT on a professional level?

use this:
http://fliptomato.wordpress.com/2006/12/30/from-griffiths-to-peskin-a-lit-review-for-beginners/

i recommend
>Griffiths, Introduction to Elementary Particles
then
>Zee, Quantum Field Theory in a Nutshell.
and
>Peskin, An Introduction to Quantum Field Theory.
starting with the canonical quantization method or the path integral method. which ever you wish.
along with the canonical quantization method read
>Greiner, Field Quantization.
and you can use
>Tong, Lectures on Quantum Field Theory.
for a summary of the material at any point.

>>4368412
not research level, if that's what you mean, no.

You?

I have a problem with the notion of different scales in renormalization. And how it's possible to find cutoff independend results. Can you elaborate on this?

>>4368409
cry more.

>>4368409
WTF is your problem?

>>4368428
reported

>>4368423
Yes, I know enough for "research level". Have you taken grad courses in QFT? (or senior courses?)

Renormalization shit all ends up being group theory. If you are good at group theroy it will make sense, else it won't. Do you know much group theory?

>>4368443
Yes, I know much group theory.
I read Zee and Peskin and Weinberg.

Well, I also read Greiner.
I'm surprised that that's in your list since it's a german book.

>>4368465
Did you take a QFT course?

>>4368472
ya. I've seen renormalization in action.
Don't know *why* it works though.

>>4368476
Well, it depends how deep down the rabbit hole you want to go.

The whole thing is pretty abstract, you must understand it on some level already though.

Is it the mathematics? The physical interpretation of the mathematics? or fundemental physic concept that is confusing you? Is it the infinity part? Alot of kids struggle with the infinity part.

>>4368476

Nobody knows. It just fits with the experimental results. Also, Path Integral method is mathematical not yet approved. It just gives the right physical reuslts.

>>4368476
Would you understand it if it didnt have a group structure? Ie, there was only one way to renormalize?

>>4368490
The part I ponder about is the role of different energy scales.
To take a step back, can you explain the renormalization using block spins in the Ising model, which has that well defined scaling law/critical exponent.
How do you stip off finite values in that system?

Also, but that might be far fetched, do you know something about renormalizaton of turbulence effcts (in connection to dissipation, e.g. in fluid systems)

<span class="math"> \mathbf{Prerequisites} [/spoiler]
Calculus
Linear algebra
Quantum mechanics
Basic functional analysis
Maybe a little harmonic analysis

Then just go pick up a basic book on QFT

>>4368508
>Quantum Mechanics
>Basic functional analysis

you make it sound so easy to OP

>>4368494
>Nobody knows

Tens of thousands of physicist would disagree with you. That shit is pretty well known. The problem I see here is that "anon" hasnt really expressed his question is a "valid scientific form".

He asks "why". Answers to "Why" questions requires some prior knowledge to understand, aka, you are trying to understand "a" in terms of "b". Anon made it clear what "a" is, but not "b". Hence until he says what "b" is his question is meaningless.

This basically applies to all "why" questions. For many "why" questions, "b" can be inferred from context. However in science often cannot, especially not in fundemental physics.

>>4368503
>can you explain the renormalization using block spins in the Ising model, which has that well defined scaling law/critical exponent.

I guess it could be done? Maybe? But why the fuck would you want to do this? The easiest way to explain renormalization is in terms of 1) just the math 2) particle physics.

If you are trying to infer the "whys of renormalization" shit from condensed matter or "macro" systems, I think you are actually taking a step backwards. Do you undersatnd how renomization comes about in particle physics? Are you studying consensed matter?

Condensed matter is neat and all, but seeing as nothing in fundemental, trying to infere some fundemental meanings to physical phenomina/processes is going to be a fucking bitch.

I know tons of guys who can get there head wrapped around symmetery-breaking (the kind used for higgs shit) because they first learned it in application to condensed matter, instead of particle physics/or just abstractly.

>>4368539
I'm currently interested in fairly macroscopic physics, but I think it's not a wrong step to try to understand the renormalization in statistical physics, given that it's usually a little easier/clearer. The ising model and related systems are well studied as well.

My basic question can probably formulated such that I ask for what the things are you throw away citation marks during the renormalization procedure. Maybe in terms of field fluctuations. But it's true that I can't properly formulate the qustion without writing down loads of tex, which I won't do here.

Ops pic doesn't include a linux

>>4368503
>>4368503
>Ising model

Good luck finding anyone who wants to explain that shit in terms of the shitty Ising model.

Renormilization isn't that hard.
1) We only observe "select" finite quantities

2) According to the fucking math/physics "actual" things end up being infinite.

3) The "select" things we observe, are made of complicated combinations the "actual" things.

4) The infinities in the "actual" things must cancel to form a "select" thing.

5) The cancellation process is not unique in any sense. In fact there are usually an infinite way to get the "select" things from the "actual" things.

6) So selecting the renomilzation then depends on some other "external" parameters. We can physically assocaite the parameters with energyscales, reference frame, etc. We do this by matching what is equivalently "boundary conditions" or "intial conditions" to what we know some "select" values to be.

7) We then have our formulas to generate "select" things that correspond to combinations of "actual" things, such that we get consistant results to already established values of certain "select" things.

Make sense? It has been awhile since i did any real QFT.

>>4368599

>>4368566
>I ask for what the things are you throw away citation marks during the renormalization procedure

Wat?

Instead of developing QFT why don''t we reduce GR?

Gravitons shmavitons, spin2myarse. quantum fabric up in this bitch.

>>4368566
>renormalization procedure

There are a lot of different renormalization procedures. Like a fucking ton. I am not sure if they are all used in condensed matter.

You really need to approach this from a abstratc math or particle physics level.

/sci/ -

I am frustrated. I attempted (briefly) to learn special/general relativity from Schutz's "A First Course of General Relativity," and I simply did not understand the math/symbols that were used. I'm not going to give up, though. What math do I need to learn to get my mind around s.r./g.r.?

tl;dr what math do I need to understand relativity?

>>4368882
Special relativity is really easy, high school algebra
General relativity bro don't even try, not even most nobel price winning physicists understand the math behind that shit. It's beyond most people.