"Classical field theory and classical mechanics"의 두 판 사이의 차이

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잔글 (찾아 바꾸기 – “<h5 (.*)">” 문자열을 “==” 문자열로)
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<h5 style="margin: 0px; line-height: 3.428em; color: rgb(34, 61, 103); font-family: 'malgun gothic',dotum,gulim,sans-serif; font-size: 1.166em; background-position: 0px 100%;">notation==
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==notation==
  
 
*  dynamical variables <math>q_{k}, \dot{q}_k</math> for <math>k=1,\cdots, N</math><br>
 
*  dynamical variables <math>q_{k}, \dot{q}_k</math> for <math>k=1,\cdots, N</math><br>
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<h5 style="margin: 0px; line-height: 2em;">canonically conjugate momentum==
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==canonically conjugate momentum==
  
 
*  canonically conjugate momenta<br><math>p_{k}=\frac{\partial L}{\partial \dot{q}_k}</math><br>
 
*  canonically conjugate momenta<br><math>p_{k}=\frac{\partial L}{\partial \dot{q}_k}</math><br>
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<h5 style="margin: 0px; line-height: 2em;">Hamiltonian mechanics==
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==Hamiltonian mechanics==
  
 
*  conjugate variables are on the equal footing<br>
 
*  conjugate variables are on the equal footing<br>
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<h5 style="margin: 0px; line-height: 2em;">Poisson bracket==
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==Poisson bracket==
  
 
For <math>f(p_i,q_i,t), g(p_i,q_i,t)</math> , we define the Poisson bracket
 
For <math>f(p_i,q_i,t), g(p_i,q_i,t)</math> , we define the Poisson bracket
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<h5 style="margin: 0px; line-height: 2em;">phase space==
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==phase space==
  
 
 
 
 

2012년 10월 28일 (일) 17:11 판

introduction

  • can be formulated using classical fields and Lagrangian density
  • change the coordinates and fields accordingly
  • require the invariance of action integral over arbitrary region
  • this invariance consists of two parts : Euler-Lagrange equation and the equation of continuity
  • three important conserved quantity
    • energy
    • momentum
    • angular momentum

 

 

notation

  • dynamical variables \(q_{k}, \dot{q}_k\) for \(k=1,\cdots, N\)
  • \(T\) kinetic energy
  • \(V\) potential energy
  • We have Lagrangian \(L=T-V\)
  • Define the Hamiltonian
  • \(H =\sum_{k=1}^{N} p_{k}\dot{q}_{k}-L\)
  • \(p\dot q\) is twice of kinetic energy
  • Thus the Hamiltonian represents \(H=T+V\) the total energy of the system

 

 

Lagrangian formalism

 

 

canonically conjugate momentum

  • canonically conjugate momenta
    \(p_{k}=\frac{\partial L}{\partial \dot{q}_k}\)
  • instead of \(q_{k}, \dot{q}_k\), one can use \(q_{k}, p_{k}\) as dynamical variables

 

 

 

Hamiltonian mechanics

 

 

 

Poisson bracket

For \(f(p_i,q_i,t), g(p_i,q_i,t)\) , we define the Poisson bracket

\(\{f,g\} = \sum_{i=1}^{N} \left[ \frac{\partial f}{\partial q_{i}} \frac{\partial g}{\partial p_{i}} - \frac{\partial f}{\partial p_{i}} \frac{\partial g}{\partial q_{i}} \right]\)

In quantization we have correspondence

\(\{f,g\} = \frac{1}{i}[u,v]\)

 

 

phase space

 

 

하위페이지

 

 

 

links and webpages

 

question and answers(Math Overflow)

 

 

 

history

 

 

related items

 

 

encyclopedia

 

 

books

 

 

expositions

  • Benci V. Fortunato D., Solitary waves in classical field theory, in Nonlinear Analysis and Applications to Physical Sciences