As a theory of physics, quantum mechanics is a branch of physics, which studies the motion law of microscopic particles in the material world. It mainly studies the basic theory of the structure and properties of atoms, molecules, condensed matter, nuclei 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.

State function:

In quantum mechanics, the state of a physical system is represented by state functions, and the arbitrary linear superposition of state functions still represents a possible state of the system. The change of state with time follows a linear differential equation, which predicts the behavior of the system. Physical quantities are represented by operators that meet certain conditions and represent some operation.

The operation of measuring the physical quantity of a physical system in a certain state corresponds to the effect of the operator representing the quantity on its state function; The possible value of measurement is determined by the eigenequation of the operator, and the expected value of measurement is calculated by the integral equation containing the operator. Generally speaking, quantum mechanics cannot predict a definite result for an observation.

Refer to the above? Baidu encyclopedia-quantum mechanics