Quantum mechanics is a branch of physics that deals with the behavior of matter and energy at the smallest scales, such as atoms and subatomic particles. It provides a new and fundamental way of understanding the physical world, which is different from classical mechanics.

General Formalism and the One-Dimensional Potential.

"Quantum Mechanics" by G. Aruldhas remains a gold standard for mastering the "weird" world of the subatomic. Its balance of theory and practice makes it an indispensable tool for any serious physics student.