Quantum Potential in Bohmian Mechanics?

[cryptist]

What is the meaning of quantum potential in de broglie-bohm theory? Is that the "hidden variable"? Or are the positions of particles "hidden variables"?

As far as I see, some references explains theory with quantum potential (Bohm, Holland) but some references explains it with guiding equation. (Dürr, Goldstein)

Has de broglie-bohm two different formalisms, or what? Are they say same thing? Can we use both of them in same formulation?

 

[Demystifier]

What is the meaning of quantum potential in de broglie-bohm theory?

It is an unnecessary element of dBB theory the only role of which is to write the theory in a form that more closely resembles Newtonian mechanics.

Is that the "hidden variable"?

No.

Or are the positions of particles "hidden variables"?

Yes.

Has de broglie-bohm two different formalisms, or what?

You can put it this way if you like, in analogy with the fact that classical mechanics has different formalisms, like those Newton, Hamilton, Lagrange, Hamilton-Jacobi, etc.

Are they say same thing? Can we use both of them in same formulation?

Yes and yes.

It should also be pointed out that in dBB theory with spin, the notion of the quantum potential is quite useless.

 

[cryptist]

Thank you for your answers. However Bohm uses quantum potential a lot (so is it really useless or unnecessary?) and as far as I understand, he describes it as active information. So are the particles move by the quantum force coming from quantum potential or they move by the guiding equation?
Because on that link: (http://plato.stanford.edu/entries/qm-bohm/#qp) it says "describing particles moving under the influence of forces, among which, however, one must include a force stemming from a "quantum potential.""

 

[Demystifier]

Thank you for your answers. However Bohm uses quantum potential a lot (so is it really useless or unnecessary?) and as far as I understand, he describes it as active information. So are the particles move by the quantum force coming from quantum potential or they move by the guiding equation?
Because on that link: (http://plato.stanford.edu/entries/qm-bohm/#qp) it says "describing particles moving under the influence of forces, among which, however, one must include a force stemming from a "quantum potential.""

I wouldn't say that quantum potential is useless, but is definitely not necessary. The notion of active information is certainly not essential, but Bohm liked it for some philosophical reasons. It is definitely simpler to think of particles as moving by the guiding equation (that determines the velocity), rather than by the quantum force (that determines the acceleration).

 

[cryptist]

Thank you very much for the answers.