"Electromagnetics"의 두 판 사이의 차이

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==Lagrangian formulation==
 
==Lagrangian formulation==
 
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* [[Lagrangian formulation of electromagetism]]
*  Lagrangian for a charged particle in an electromagnetic field <math>L=T-V</math>
 
:<math>L(q,\dot{q})=m||\dot{q}||-e\phi+eA_{i}\dot{q}^{i}</math><br>
 
*  action
 
:<math>S=-\frac{1}{4}\int F^{\alpha\beta}F_{\alpha\beta}\,d^{4}x</math><br>
 
*  Euler-Lagrange equations
 
:<math>p_{i}=\frac{\partial{L}}{\partial{\dot{q}^{i}}}=m\frac{\dot{q}_{i}}{||\dot{q}_{i}||}+eA_{i}=mv_{i}+eA_{i}</math>
 
$$
 
F_{i}=\frac{\partial{L}}{\partial{q^{i}}}=\frac{\partial}{\partial{{q}^{i}}}(eA_{j}\dot{q}^{j})=e\frac{\partial{A_{j}}}{\partial{q}^{i}}\dot{q}^{j}
 
$$
 
*  equation of motion<br><math>\dot{p}=F</math> Therefore we get
 
:<math>m\frac{dv_{i}}{dt}=eF_{ij}\dot{q}^{j}</math>. This is what we call the Lorentz force law.<br>
 
* force on a particle is same as <math>e\mathbf{E}+e\mathbf{v}\times \mathbf{B}</math>
 
* THOMAS YU [http://math.uchicago.edu/~may/REU2012/REUPapers/Yu.pdf LAGRANGIAN FORMULATION OF THE ELECTROMAGNETIC FIELD]
 
* http://dexterstory.tistory.com/888<br>
 
* [[path integral formulation of quantum mechanics|path integral]]<br>
 
 
 
 
 
  
 
 
 
 
105번째 줄: 88번째 줄:
  
 
==books==
 
==books==
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* ELECTROMAGNETIC THEORY AND COMPUTATION
  
ELECTROMAGNETIC THEORY AND COMPUTATION
 
 
[[분류:math and physics]]
 
[[분류:math and physics]]

2013년 3월 23일 (토) 10:15 판

gauge invariance

  • the electromagnetic potential is a connection on a U(1)-bundle on spacetime whose curvature is the electromagnetic field
  • the electromagnetism is a gauge field theory with structure group U(1)

 

 

Lorentz force

  • almost all forces in mechanics are conservative forces, those that are functions only of positions, and certainly not functions of velocities
  • Lorentz force is a rare example of velocity dependent force

 

 

polarization of light

  • has two possibilites
    • what does this mean?

 

 

 

Lagrangian formulation

 

Hamiltonian formulation

  • total energy of a charge particle in an electromagnetic field
    \(E=\frac{1}{2m}(p_j-eA_{j})(p_j-eA_j)+q\phi\)
  • replace the momentum with the canonical momentum
    • similar to covariant derivative

 

 

force on a particle

  • force on a particle is same as \(e\mathbf{E}+e\mathbf{v}\times \mathbf{B}\)

 

 

 

 

메모

 

 

related items

 

 

encyclopedia

 

 

books

  • ELECTROMAGNETIC THEORY AND COMPUTATION