How Does the Hamilton-Jacobi Equation Reveal Solutions Depending on Potential V?

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Discussion Overview

The discussion revolves around the Hamilton-Jacobi equation and its solutions in relation to the potential function V. Participants explore the existence and uniqueness of solutions, boundary conditions, and the implications of different forms of the potential function.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents the Hamilton-Jacobi equation and questions the existence of exact solutions depending on the potential V.
  • Another participant suggests the use of the implicit function theorem in relation to the problem.
  • A different participant claims that the existence and uniqueness of the solution can be proven but asks for clarification on the meaning of the term \(\nabla{S})^{2}\) and the boundary conditions involved.
  • Further clarification is provided that \((\nabla S)^2\) refers to the square of the gradient of S, and a suggestion is made to establish an equivalent system of ODEs for the nonlinear problem.
  • One participant mentions the application of nonlinear semigroup theory in this context.
  • Another participant notes that certain coordinate systems and forms of the potential function can facilitate the separation of variables, referencing Landau's book on mechanics.

Areas of Agreement / Disagreement

Participants express differing views on the methods to approach the problem, including the use of the implicit function theorem and nonlinear semigroup theory. The discussion remains unresolved regarding the specifics of boundary conditions and the implications of different potential functions.

Contextual Notes

Participants have not fully defined the assumptions regarding boundary conditions, the specific forms of the potential function, or the mathematical steps necessary for proving existence and uniqueness.

eljose
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Let be the S function being the action in physics S=S(x,y,z,t) satisfying the equation:

[tex]\frac{dS}{dt}+(1/2m)(\nabla{S})^{2}+V(x,y,z,t)=0[/tex]

where V is the potential is there any solution (exact) to it depending on V?
 
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Implicit function theorem?
 
We can prove the existence and the unicity of the solution ,
What do you mean by[tex]\nabla{S})^{2}[/tex] is it the laplacian of S?
what is your boundary condition?is it Dirichlet or Neuman?
 
i m still wait your reponse
 
[tex](\nabla S)^2=|\nabla S|^2 \qquad \hbox{the square gradient}[/tex]

you can establish an equivalent system of ode's for your nonlinear problem and then aswer the questions for existence, unicity and solvability...
for more details check first chapter of Fritz John book.
 
In this case we can use the nonlinear semi group theory
 
There are system of coordinates and forms of the potential function as to insure full separation of variables...See Landau's book on mechanics.

Daniel.
 

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