Generalized gauge invariants for certain nonlinear Schrödinger equations
The author introduces a new class of nonlinear gauge transformations of the wave function, which involve the phase \(S\) of the wave function and the logarithm \(T\) of its amplitude. As a result, the linear Schrödinger equation is embedded in a natural class of nonlinear evolution equations, invariant as a class under gauge transformations. Some expressions containing \(S\) and \(T\), and invariant with respect to gauge transformations, are found.NEWLINENEWLINEFor the entire collection see [Zbl 0937.00046].
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