Ansatz: Principle, Hypothesis, Boundary Condition?

[navigator]

What is ansatz? such as Bethe ansatz. Is it a principle? hypothesis? or boundary condition? self-consistency condition? Why the Heisenberg system has to obey the ansatz? Could it be violated? If it can not be deduced, how could we verify it is true? and why do we believe the solution is exact?

 

[malawi_glenn]

An ansatz is in general a proposal for a solution.

For example when you are solvning PDE's, and have homogenous BC, you often make the ansatz of separation variables. etc.

http://en.wikipedia.org/wiki/Ansatz