Hello, I have been wondering about the validity of Maxwell's equations in quantum physics. I looked in the internet and it seems from what I understood that: Maxwell's equations are valid for any situation, classical or quantum. In fact, maybe it holds more legitimacy than Schroedinger equation since it is a relativistic (invariant) set of equations. Yet, I am really baffled! The equations said to be valid, yet I don't see any wave function in it. (Ok, this might be hilarious. But, any equation I see in quantum physics have a wave function and probability distribution!). Are the electric and magnetic fields alongside the functions ##\rho \ \& \ J## probabilistic! My question is, how Maxwell's equations are implemented/related to quantum physics? Why it is not usually in use? *Disclaimer: I am undergraduate student, and I don't have that much experience with quantum physics. **I would appreciate it if you supported your replies with references of books and papers.