On Lewis Exact Invariant For The Linear Harmonic-Oscillator With Time-Dependent Frequency
Abbreviated Journal Title
Phys. Lett. A
In this paper we purport to show that Lewis' exact invariant for a linear harmonic oscillator with a time-dependent frequency arises as a consequence of the invariance of the problem under local Lie groups of transformations. We will also show that Lewis' invariant can be deduced via a systematic perturbation theory for the case with slowly-varying frequency as a power series in the small parameter epsilon characterizing the slow variations in the frequency.
Physics Letters A
"On Lewis Exact Invariant For The Linear Harmonic-Oscillator With Time-Dependent Frequency" (1991). Faculty Bibliography 1990s. 338.