"Anomalous magnetic moment of electron"의 두 판 사이의 차이

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<h5>introduction</h5>
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==introduction</h5>
  
 
* amplitude = sum of integrals = <math>\sum_{n\text{ loops}}</math> sum of integrals
 
* amplitude = sum of integrals = <math>\sum_{n\text{ loops}}</math> sum of integrals
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<h5>classical magnetic moment</h5>
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==classical magnetic moment</h5>
  
 
* read [[spin system and Pauli exclusion principle|spin system]] first
 
* read [[spin system and Pauli exclusion principle|spin system]] first
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<h5>anamalous electron magnetic dipole moment</h5>
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==anamalous electron magnetic dipole moment</h5>
  
 
* In Dirac’s theory a point like spin 1/2 object of electric charge q and mass m has a magnetic moment: <math>\mathbf{\mu}=q\mathbf{S}/m</math>
 
* In Dirac’s theory a point like spin 1/2 object of electric charge q and mass m has a magnetic moment: <math>\mathbf{\mu}=q\mathbf{S}/m</math>
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<h5>two-loop diagrams</h5>
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==two-loop diagrams</h5>
  
 
*  7 two-loop diagrams<br>[/pages/3589069/attachments/4562669 2004329153354_150.gif]<br>[/pages/7141159/attachments/4562733 I15-62-g2c.jpg]<br>
 
*  7 two-loop diagrams<br>[/pages/3589069/attachments/4562669 2004329153354_150.gif]<br>[/pages/7141159/attachments/4562733 I15-62-g2c.jpg]<br>
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<h5>three-loop diagrams</h5>
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==three-loop diagrams</h5>
  
 
* 72 three-loop diagrams
 
* 72 three-loop diagrams
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<h5>four-loop diagrams</h5>
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==four-loop diagrams</h5>
  
 
*  891 diagrams
 
*  891 diagrams
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<h5>five-loop Feynman diagrams</h5>
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==five-loop Feynman diagrams</h5>
  
 
* There are 12,672
 
* There are 12,672
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<h5>memo</h5>
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==memo</h5>
  
 
* [http://aias.us/documents/uft/a18thpaper.pdf Calculation of the Anomalous Magnetic Moment of the Electron from the Evans-Unified Field Theory]<br>
 
* [http://aias.us/documents/uft/a18thpaper.pdf Calculation of the Anomalous Magnetic Moment of the Electron from the Evans-Unified Field Theory]<br>
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<h5>history</h5>
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==history</h5>
  
 
* http://www.google.com/search?hl=en&tbs=tl:1&q=
 
* http://www.google.com/search?hl=en&tbs=tl:1&q=
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<h5>related items</h5>
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==related items</h5>
  
 
 
 
 
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<h5>books</h5>
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==books</h5>
  
 
 
 
 
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<h5>expositions</h5>
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==expositions</h5>
  
 
* Brian Hayes, “g-OLOGY,” American Scientist 92, no. 3 (2004): 212. http://www.americanscientist.org/issues/num2/g-ology/1
 
* Brian Hayes, “g-OLOGY,” American Scientist 92, no. 3 (2004): 212. http://www.americanscientist.org/issues/num2/g-ology/1
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<h5>question and answers(Math Overflow)</h5>
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==question and answers(Math Overflow)</h5>
  
 
* http://mathoverflow.net/search?q=
 
* http://mathoverflow.net/search?q=
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<h5>blogs</h5>
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==blogs</h5>
  
 
*  구글 블로그 검색<br>
 
*  구글 블로그 검색<br>
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<h5>experts on the field</h5>
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==experts on the field</h5>
  
 
* http://arxiv.org/
 
* http://arxiv.org/
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<h5>links</h5>
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==links</h5>
  
 
* [http://detexify.kirelabs.org/classify.html Detexify2 - LaTeX symbol classifier]
 
* [http://detexify.kirelabs.org/classify.html Detexify2 - LaTeX symbol classifier]

2012년 10월 28일 (일) 13:52 판

==introduction

  • amplitude = sum of integrals = \(\sum_{n\text{ loops}}\) sum of integrals
  • anomalous electron magnetic dipole moment 1.00115965219
  • theoretical computation matches 11 digits with experiments
  • as n grows, number of Feynman diagrams grows exponentially
  • integrals are becoming difficult

 

 

==classical magnetic moment

 

 

==anamalous electron magnetic dipole moment

  • In Dirac’s theory a point like spin 1/2 object of electric charge q and mass m has a magnetic moment\[\mathbf{\mu}=q\mathbf{S}/m\]
  • so the Bohr magneton of the electron (http://en.wikipedia.org/wiki/Bohr_magneton)  becomes
    \(\mu_\mathrm{B} = {{e \hbar} \over {2 m_\mathrm{e}}}\) since the spin of the electron is \(S=\frac{\hbar}{2}\)
  • but in QED, there are correction terms to this
  • actual spin magnetic moment of the electron involves the spin g-factor (gyromagnetic ratio)
    \(\vec{\mu}_S \ = g_e \mu_\mathrm{B} \frac{\vec{S}}{\hbar}=g\frac{e}{2 m_{e}} \ \vec{S}\)
  • classical vs quantum
    [/pages/3589069/attachments/4562673 2004329152457_150.gif]

 

  • The g factor sets the strength of an electron’s interaction with a magnetic field.
  • In classical physics (left) magnetic lines of force (perpendicular to the page) induce a curvature in the electron’s path.
  • In quantum electrodynamics (right) the electron interacts with the field by emitting or absorbing a photon.
  • The event is represented in a Feynman diagram, where space extends along the horizontal axis and time moves up the vertical axis.
  • \(g/2=1+c_1\frac{\alpha}{2\pi}+c_2(\frac{\alpha}{2\pi})^2+c_3(\frac{\alpha}{2\pi})^3+\cdots=1.00115965219+\cdots\)
  • http://www.wolframalpha.com/input/?i=fine+structure+constant
  • http://www.wolframalpha.com/input/?i=1/fine+structure+constant

 

 

 

tree level and one-loop diagrams
  • 1 one-loop diagram
    [/pages/7141159/attachments/4563145 2004329152921_150.gif]
  • Feynman, Julian Schwinger, Sin-Itiro Tomonaga and Freeman Dyson
  • Schwinger showed that the one-loop contribution to the "anomalous magnetic moment" of the electron is \(\alpha/{2\pi}=0.00116\cdots\)
  • Schwinger, Julian. 1948. On Quantum-Electrodynamics and the Magnetic Moment of the Electron. Physical Review 73, no. 4 (February 15): 416. doi:10.1103/PhysRev.73.416
     
  • http://www.wolframalpha.com/input/?i=fine+structure+constant%2F%282pi%29

 

 

==two-loop diagrams

  • 7 two-loop diagrams
    [/pages/3589069/attachments/4562669 2004329153354_150.gif]
    [/pages/7141159/attachments/4562733 I15-62-g2c.jpg]

 

 

==three-loop diagrams

  • 72 three-loop diagrams
  • [/pages/3589069/attachments/4562671 200432915395_150.gif]
  • Kinoshita, Toichiro. 1995. New Value of the alpha^{3} Electron Anomalous Magnetic Moment. Physical Review Letters 75, no. 26 (December 25): 4728. doi:10.1103/PhysRevLett.75.4728
     

 

 

==four-loop diagrams

  •  891 diagrams

 

 

==five-loop Feynman diagrams

 

 

 

anaomalous muon magnetic dipole moment

 

 

==memo

 

 

==history

 

 

==related items

 

 

encyclopedia

 

 

==books

 

 

 

==expositions

 

 

articles

 

 

==question and answers(Math Overflow)

 

 

==blogs

 

 

==experts on the field

 

 

==links