Simple Harmonic Oscillator, Series, and Fourier Transform and Sturm-Liouville Operator – A Brief Discussion

In this work we highlight the importance of the simple harmonic oscillator as a fundamental mathematical model for the understanding of oscillatory phenomena in several areas of Physics and Engineering, emphasizing the need to know the methods for its solution, which serve as a starting point for studying systems more complex. Although this topic is relevant, many studies are limited to practical applications or general solutions of differential equations, with no significant connection between concepts. In this sense, an approach is proposed that explores the relationship between the harmonic oscillator, series and Fourier transform. Through the theory of the Sturm-Liouville linear operator, we introduce concepts such as the eigenfunctions of a Hermitian operator, orthogonality, and the formation of vector spaces. While the series appears as an expansion on an infinite basis of functions within a finite interval, the transform arises as a projection of mathematical objects such as functions and equations onto the space of the oscillator’s eigenfunctions into an infinite interval. It is hoped that this approach will stimulate discussions and facilitate the understanding of more advanced topics in Physics and related areas, making them more accessible to undergraduate and graduate students.

Keywords:
Harmonic oscillator; series and Fourier transform; Sturm-Liouville operator