Difference between revisions of "User:Nik"

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Let  
 
Let  
$$ \Phi \in C^\infty(\mathbb{R}^n) $$
+
\( \Phi \in C^\infty(\mathbb{R}^n) \)
 
have the property that the system  
 
have the property that the system  
$$p_i = \frac{\partial}{\partial q_i} \Phi (q, \widetilde{q}) $$
+
\( p_i = \frac{\partial}{\partial q_i} \Phi (q, \widetilde{q}) \)
 
has a unique smooth solution  
 
has a unique smooth solution  
$$ \widetilde{q} = \widetilde{q} (q,p) $$
+
\( \widetilde{q} = \widetilde{q} (q,p) \).
  
Define
+
Define  
$$ \widetilde{p_i}(q,p) = - \frac{\partial}{\partial \widetilde{q_i}} \Phi (q, \widetilde{q}) | _{\widetilde{q}= \widetilde{q}(q,p)} $$
+
\( \widetilde{p_i}(q,p) = - \frac{\partial}{\partial \widetilde{q_i}} \Phi (q, \widetilde{q}) | _{\widetilde{q}= \widetilde{q}(q,p)} \)
  
Let $$ \{\cdot,\cdot\} $$ be the Poisson bracket, such that
+
Let \( \{\cdot,\cdot\} \) be the Poisson bracket, such that
$$ \{f,g\} = \sum_{j=1}^n \frac{\partial f}{\partial q_j} \frac{\partial g}{\partial p_j} - \frac{\partial f}{\partial p_j} \frac{\partial g}{\partial q_j} $$
+
\(  \{f,g\} = \sum_{j=1}^n \frac{\partial f}{\partial q_j} \frac{\partial g}{\partial p_j} - \frac{\partial f}{\partial p_j} \frac{\partial g}{\partial q_j} \)
 +
 
 +
Show that:
  
Show that: $$\\$$
 
 
i)
 
i)
$$ \{\widetilde{q_i} (q,p), \widetilde{q_j} (q,p)\} = \{\widetilde{p_i} (q,p), \widetilde{p_j} (q,p)\} = 0 $$
+
\( \{\widetilde{q_i} (q,p), \widetilde{q_j} (q,p)\} = \{\widetilde{p_i} (q,p), \widetilde{p_j} (q,p)\} = 0 \)
  
 
ii)
 
ii)
$$ \{\widetilde{q_i} (q,p), \widetilde{p_j} (q,p)\} = \delta_{ij} $$
+
\( \{\widetilde{q_i} (q,p), \widetilde{p_j} (q,p)\} = \delta_{ij} \)
  
  
 
=== Solution for i) ===
 
=== Solution for i) ===
 
=== Solution for ii) ===
 
=== Solution for ii) ===

Revision as of 10:50, 28 December 2014

Let \( \Phi \in C^\infty(\mathbb{R}^n) \) have the property that the system \( p_i = \frac{\partial}{\partial q_i} \Phi (q, \widetilde{q}) \) has a unique smooth solution \( \widetilde{q} = \widetilde{q} (q,p) \).

Define \( \widetilde{p_i}(q,p) = - \frac{\partial}{\partial \widetilde{q_i}} \Phi (q, \widetilde{q}) | _{\widetilde{q}= \widetilde{q}(q,p)} \)

Let \( \{\cdot,\cdot\} \) be the Poisson bracket, such that \( \{f,g\} = \sum_{j=1}^n \frac{\partial f}{\partial q_j} \frac{\partial g}{\partial p_j} - \frac{\partial f}{\partial p_j} \frac{\partial g}{\partial q_j} \)

Show that:

i) \( \{\widetilde{q_i} (q,p), \widetilde{q_j} (q,p)\} = \{\widetilde{p_i} (q,p), \widetilde{p_j} (q,p)\} = 0 \)

ii) \( \{\widetilde{q_i} (q,p), \widetilde{p_j} (q,p)\} = \delta_{ij} \)


Solution for i)

Solution for ii)