Quantum mechanics QM is a branch of physics which deals with
physical phenomena at microscopic scales, where the action is on the order of
the Planck Constant. Quantum mechanics deviates from classical mechanics mainly
at the quantum realm of atomic and subatomic length scales. Quantum mechanics
offers a mathematical description of much of the dual particle-like and
wave-like behavior and interactions of energy and matter. Quantum mechanics is
the non-relativistic limit of Quantum Field Theory (QFT), a theory that was
built up later that united Quantum Mechanics with Relativity Theory.

Quantum mechanics is the body of scientific values that elucidates
the behavior of matter and its interactions with energy on the scale of atoms
and subatomic particles and how these happenings could be linked to daily life.