Example of a question/discussion

I was trying to implement the harmonic oscillator time dependent example in this chapter of the book Application 4: Time Dependent Systems (evolution in the reduced space) — Dimensionality Reduction in Nuclear Physics. They seem to be using a matrix for derivatives, but I don’t understand how that works:

Also, what are derivatives? And what are matrices?

A derivative is basically a rate of change, which is the slope of a graph in simple terms, As for your answer to the matrices question, matrices can represent physical systems that can be told by linear equations like quantum mechanics :)) They could be used to represent quantum states, and operators, and matrix operations, I think, are used to calculate probabilities and determine the evolving of quantum systems.

Guys, How do I find the total angular momentum of a hadron or any particle for that case?