Quantum mechanics
Quantum Mechanics is a branch of physics that studies the laws governing the motion of microscopic particles in the physical world. It mainly studies the basic theories of atoms, molecules, condensed matter, and the structure and properties of nucleus and elementary particles. Together with the theory of relativity, it forms the theoretical basis of modern physics. Quantum mechanics is not only one of the basic theories of modern physics, but also widely used in chemistry and many modern technologies.
At the end of the 19th century, it was discovered that the old classical theory could not explain the microscopic system. Therefore, through the efforts of physicists, quantum mechanics was created in the early 20th century to explain these phenomena. Quantum mechanics fundamentally changes human understanding of material structure and its interactions. In addition to the gravitational pull of general relativity, all basic interactions to date can be described within the framework of quantum mechanics (quantum field theory).