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classes:2009:fall:phys4101.001:q_a_1202

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classes:2009:fall:phys4101.001:q_a_1202 [2009/12/02 19:48] – x500_hakim011classes:2009:fall:phys4101.001:q_a_1202 [2009/12/06 21:49] (current) – ely
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 ====Captain America 12-02 10:39==== ====Captain America 12-02 10:39====
 Can anyone explain how to find the value you want on the Clebsch-Gordon table?  I read the bottom of page 187, but I'm still confused when given a problem how to find out which part of the table to look at (the example is 2 X 1 with the total spin of 3 and the z component 0).  How do you get those four values out of a problem?  Should be easy, but I'm having difficulties with it. Can anyone explain how to find the value you want on the Clebsch-Gordon table?  I read the bottom of page 187, but I'm still confused when given a problem how to find out which part of the table to look at (the example is 2 X 1 with the total spin of 3 and the z component 0).  How do you get those four values out of a problem?  Should be easy, but I'm having difficulties with it.
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 +===Devlin ===
 +I'm also having some serious issues with this table.
  
 ===prest121 12/2 5:50pm=== ===prest121 12/2 5:50pm===
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 What makes the 3-body problem --or the n-body problem for n>2-- so difficult? I've heard of the issue in modern physics, astro, and quantum, but I've never seen the problem set up or how there would arise a mathematical barrier. I guess I'll look it up or try to set it up myself. I'm sure the problem will present itself quickly. What makes the 3-body problem --or the n-body problem for n>2-- so difficult? I've heard of the issue in modern physics, astro, and quantum, but I've never seen the problem set up or how there would arise a mathematical barrier. I guess I'll look it up or try to set it up myself. I'm sure the problem will present itself quickly.
 +
 +=== The Doctor 12/3 1:31 AM ===
 +The variety of divergent trajectories with various Lyapunov exponents makes the problem too difficult for undergraduate courses.  So says wikipedia.
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 +===Dark Helmet 12/6 21:46===
 +My understanding is that it just gets really really complicated because the interaction of body 1 with body 2 changes how they interact with body 3 which then changes again how body 1 and 2 react, etc etc.  However, i think this problem only applies when doing it by hand considering the large number of N body simulations that are being done by computer(dark matter collapse, what-have-you).  
 +
 ====Hydra 12/2==== ====Hydra 12/2====
 In class when we found the<math> L_{-}=\sqrt{2}\to</math> , what equation yields the <math> \sqrt{2}</math> In class when we found the<math> L_{-}=\sqrt{2}\to</math> , what equation yields the <math> \sqrt{2}</math>
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 I think equation 4.121: <math>A_lm=\hbar\sqrt{(l+-m)(l-+m+1)}</math> I think equation 4.121: <math>A_lm=\hbar\sqrt{(l+-m)(l-+m+1)}</math>
  
 +====Blackbox 12/3====
 +On page 164, the equation between 4.112 and 4.113, why L_L+ becomes zero? Is this the reason that L+*ft is zero?
  
- +===Captain America 12/4 10:57=== 
 +Yes, I believe this is the case.  The <math>L_+</math> operator should act on <math>f_t</math> first, and as equation 4.110 on page 163 points out, it is 0.
  
  
classes/2009/fall/phys4101.001/q_a_1202.1259804931.txt.gz · Last modified: 2009/12/02 19:48 by x500_hakim011

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