The theoretical physics is the branch of the Physique which studies the theoretical aspect physical laws and the mathematical formalism of it develops.

It constitutes an intermediate field of studies between the experimental Physique and mathematics, and often contributed to the development of like the other.

The theoretical physics should not be confused with the Mathematical physics, this branch of mathematics which proposes to return entirely rigorous the often vague statements of the theorists.

Theories and models

The theoretical physics try to describe the world by carrying out Modèle S of reality, used in order to rationalize, to explain and predict physical phenomena through a “physical theory”. There are in physics three types of theories: fundamental theories, theories suggested but not validated, and marginal theories (bad translation of “mainstream theories, proposed theories and fringe theories”).

Certain physical theories are confirmed by the observation whereas others are not it. A physical theory is a model of physical events and cannot be proven starting from basic axioms; in that a physical theory differs from a mathematical theorem. The physical theories model reality and are at the same time a reflection of the observations, and a source of prediction of new observations.

The physical theories can be accepted when they at the same time make it possible to make correct predictions and to avoid making erroneous predictions. The physical theories simplest are generally preferred with those which are complex, in accordance with the rule known under the name of “Rasoir of Ockham”. The physical theories most likely of meaning are those which connect a great quantity of phenomena. The process of test of a physical theory belongs to the scientific method.

Some theories

The table below gathers theories which (still) were not contradicted. The commonly accepted theories are in green, the speculative theories are beige. They are classified by date. It should well be noted that two commonly accepted theories can give different results: for example, the Newtonian Mécanique will be less precise than the general Theory of relativity in Cosmologie. Each theory has its own scope of application (thus, the restricted Relativité makes it possible to extend this field at the speeds close speed of light).

Let us note finally that one calls:

• a Theory of the Whole a theory which describes all the physical phenomena.
• a quantum Revolved a theory which gathers the theory of the General relativity and the quantum Mécanique.
• a Theory of gauge a theory based on groups of symmetries acting as each point of the universe separately.

Others

The particular position of the theoretical physics to crossed mathematics and physics led the French mathematician Souriau to propose this amusing definition of it: