Condition (quantum mechanics)

in quantum mechanics is defined the condition of a physical system regarding a given theory as epitome of a minimum set physical dimension, from whose knowledge in the context of the theory the maximally possible information can be derived over the system. For the conditionthere is an evolution equation in the theory concerned, from which results, how the condition develops for example temporally. This temporal development of the condition is called process.

For example the condition is given to the involved in the classical mechanics by the places and impulsesParticle. From these data then all other physical dimension leave themselves, as energies, angular momenta and so on to compute. To note it is here that the condition is thus observable in the classical mechanics observabel, because places and impulses are measurable.

In quantum mechanics is the condition given by an abstract not observable mathematical function <math> \ psi (\ vec r, t)< /math>, in the simplest case of a function of space and time, the waving in such a way specified or <math> \ psi< /math> - function. These functions certainly as solutions of the pertinent development equation, the Schroedinger equation.

The substantial innovation consists of the fact thatthe condition of the system by a not observable function is represented. The further consequence from it is the statistic interpretation of this condition. The wave function supplies no more places of particles, but determines stay probabilities, thus how often itself with a very large number of particlesin the same condition, a certain fraction within a certain space range stops.

Quantum states of atoms and molecules are often marked by term symbols.

See also: Density matrix, term symbol