Conserved charge generates symmetry transformation in Hamiltonian Mechanics

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SUMMARY

The discussion centers on the proof that a conserved charge Q generates a symmetry transformation in Hamiltonian mechanics, specifically showing that q + εδq satisfies the equation of motion. The key relationship established is δq = {q, Q}, leading to the conclusion that the time derivative of q' can be expressed in terms of the Hamiltonian H. The proof was initially incomplete due to the oversight of changes in momentum p, which was later acknowledged as a critical factor in the derivation.

PREREQUISITES
  • Understanding of Hamiltonian mechanics and Poisson brackets
  • Familiarity with the concept of conserved charges in physics
  • Knowledge of symmetry transformations in classical mechanics
  • Basic proficiency in calculus and differential equations
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  • Study the role of conserved quantities in Hamiltonian dynamics
  • Learn about Poisson bracket properties and their applications
  • Explore symmetry transformations and Noether's theorem in classical mechanics
  • Investigate the implications of momentum changes in Hamiltonian systems
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This discussion is beneficial for physicists, particularly those specializing in classical mechanics, as well as students and researchers interested in the mathematical foundations of Hamiltonian systems and symmetry principles.

kakarukeys
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[tex]Q[/tex] is a conserved charge if [tex]\{Q, H\} = 0[/tex]
Show that [tex]q+\epsilon\delta q[/tex] satisfies the equation of motion.
[tex]\delta q = \{q, Q\}[/tex]

I couldn't find the proof. Anybody knows?
My workings:
[tex]\delta q = \{q, Q\}[/tex]
[tex]\delta\dot{q} = \{\{q,Q\},H\} = - \{\{Q,H\},q\} - \{\{H,q\},Q\}[/tex]
[tex]\delta\dot{q} = \{\{q,Q\},H\} = \{\{q,H\},Q\}[/tex]
[tex]\delta\dot{q} = \{\{q,Q\},H\} = \{\dot{q},Q\}[/tex]
Let [tex]q' = q+\epsilon\delta q[/tex]
Show that [tex]\dot{q'} = \{q,H\}|_{q'}[/tex]
L.H.S. is [tex]\dot{q}+\epsilon\delta\dot{q}[/tex]
R.H.S is [tex]\{q,H\}+\epsilon\partial_q\{q,H\}\delta q[/tex]
Therefore we have to prove [tex]\{\dot{q},Q\} = \partial_q\{q,H\}\{q,Q\}[/tex]
...
No clue how to continue
 
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Solved! I neglected the change in p
 

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