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"Renormalization"

28 Comments -

1 – 28 of 28
Anonymous Anonymous said...

How would this work for same-sex particles?

1:02 PM, November 11, 2007

Anonymous Mars said...

OMG this is brilliant!!

1:58 PM, November 11, 2007

Blogger Bee said...

Hi Anonymous,

ff: multiply HE-vertices with s
mm: divide SHE-vertices by s

I haven't worked with that model, so I'm not sure whether the additional symmetry factor affects cross-sections.

Hi Mars,

Thanks :-) Say hello to Venus,

B.

2:09 PM, November 11, 2007

Blogger stefan said...

Dear Bee,

that's great :-)

Best, Stefan

2:11 PM, November 11, 2007

Blogger Neil' said...

This is cute, and remember that physics is different for "dressed" than for "undressed" particles!
But what about "real" renormalization: Is it a reasonable theory, or a contrived hack? Even if you take polarization of the vacuum into account, what is the integral of field energy around an electron down to the alleged "point" center, or to a string of some kind? I still don't see how it could be less than the mass of the electron, since field energy density varies as intensity squared and there's a "long way to go."

But if the integrated field mass equivalent is more than m_e, then there's a contradiction. Don't say, that's just a classical problem, because the same issue should be relevant - only the handling of it would be different.

I've asked before in different places for a graph of electric field around a "dressed" electron as deviation from simple 1/r^2 as would be classically for a charge with distant flux of that charge. I have yet to see it referenced.

2:44 PM, November 11, 2007

Blogger Bee said...

Hi Neil,

well, I assume you can read what the textbooks say, so I interpret your question as asking for my opinion. I think renormalization is a doable but ugly way to deal with our lack of knowledge about what 'really' happens at Planckian energies.

Even in classical EM, the potential is defined only up to a constant, and you can only measure potential differences.

Best,

B.

3:07 PM, November 11, 2007

Blogger Neil' said...

Thanks, Bee.

One point to clarify if you have a minute: you spoke of potential, but IIUC the field energy density is based on field strength, and is therefore an absolute ('tho may be hard to define in the regions close to the electron's source.)

5:16 PM, November 11, 2007

Blogger Bee said...

What I was actually talking about in my above comment is renormalization : :, normal ordering of operators. What I was talking about in the post is renormalization of the bare masses/couplings.

5:32 PM, November 11, 2007

Blogger Frank said...

Brilliant! :D

5:35 PM, November 11, 2007

Anonymous Anonymous said...

I thought I had typed to go to asymptotia, and I was wondering why Clifford was tryng Bee-ish jokes :) .

6:30 PM, November 11, 2007

Blogger Bee said...

glad I didn't add the line about asymptotic freedom that I had in mind - it would have confused you even more ;-)

7:49 PM, November 11, 2007

Anonymous Anonymous said...

Confusion , (and the subsequent unravelling) are useful :). So, I would love to hear the part about asymptotic freedom.

8:20 PM, November 11, 2007

Blogger Aaron said...

OMG yes. :)

Incidentally, I just learned in my E&M class if you treat a point charge distribution as a continuous charge distribution, its total energy seems to be infinite! Now the idea of renormalization seems a lot less shady to me...

9:05 PM, November 11, 2007

Anonymous Domenic Denicola said...

Oh man, this is totally going on the wall outside my door. Most excellent!

9:12 PM, November 11, 2007

Blogger CapitalistImperialistPig said...

I think that you need more than two sexes to make these diagrams convergent.

11:10 PM, November 11, 2007

Blogger Arun said...

When she likes him, and he likes her, it is a Yes-matrix element.

12:37 AM, November 12, 2007

Anonymous Chris Oakley said...

I think that there ought to be a (1/2!)^2 symmetry factor since there are identical particles in the initial & final states; for same-sex particles the graphs ought to be the same unless they are all in the final or all in the initial states, which you could get by crossing, e.g. one chick having a crush on three other chicks simultaneously.

If the lesbian 1 on 3 experiment is ever carried out, it could be funded by having a subscription services to the video footage on the internet, thus avoiding the tiresome process of filling in grant application forms.

3:44 AM, November 12, 2007

Anonymous Cynthia said...

Now I don't know what Gross and Wilczek would say about this picture of renormalization, but I'll say that asymptotic freedom could bring much needed heat (and spice) to it!

7:41 AM, November 12, 2007

Blogger Bee said...

Hi Anonymous,

well, it was only one sentence saying the strong interaction is asymptotically free. it lead my thoughts running towards confinement however, and I found I shouldn't overstretch it. It's kind of interesting though, I've referred earlier to communication as 'gluons' and occasionally it seems to me that the stronger the coupling and the denser the medium, the less confinement. That is to say, it seems to be much more accepted to stay single today than, say, 100 years ago, and families dissolve into social networks. Where's the hadronization gone? Best,

B.

9:45 AM, November 12, 2007

Blogger Chanda in The Disordered Cosmos said...

rotfl

11:19 AM, November 12, 2007

Anonymous Uncle Al said...

When states cross in chemistry they instead split and separate, or Jahn-Teller distortion diddles the outcome. This models why academic chemistry labs are well-staffed on Friday and Saturday nights.

If NSF won't fund this reasrch, NIH will get all jiggy wit it.

1:02 PM, November 12, 2007

Blogger Arun said...

"He likes her" and "She likes him" often leads to super-something.

7:55 PM, November 12, 2007

Blogger Bee said...

sorry, our server is down, so the pics are gone. hopefully back up and running later today.

9:28 AM, November 13, 2007

Blogger stefan said...

our server is down, so the pics are gone. hopefully back up and running later today.

This seems to be quite a severe problem - not only the web services are affected, but email and remote access doesn't work either. And usually, the problem is fixed within a few hours. Now, I fear that the outage will persist at least until tomorrow, i.e. for more than 12 hours...

3:44 PM, November 13, 2007

Blogger Bee said...

Aaaahhh!! Here we go! One Googol of thanks to the never-sleeping system admin back at the ITP in Frankfurt :-)

5:12 PM, November 13, 2007

Blogger nige said...

Just as well both particles thought they liked one another. What if it was a case of unrequited love?
:-(

3:56 PM, November 17, 2007

Anonymous David N said...

Nice

As for unrequited love - some sort of no-go theorem perhaps?

8:39 PM, November 21, 2007

Anonymous fep said...

ahaha so funny and cute!

Amazing post! Actually all your humor posts are awesome! Just met your blog and I can't stop reading it!

Best,
Fernanda..

3:02 AM, July 08, 2009

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