Theoretical physics

theoretical physics describes regularities of physics by mathematically formulated theories. A physical theory is thereby not simply a summary of the results of past experiments, but provides a constant description of a subrange of the reality,their assistance the results of new, yet not accomplished experiments to be predicted know. Experimental physics examines then again the theory, as appropriate experiments are accomplished. Although the theories are more than only consequences from the experiments, in the long run the experiments havethe last word: If a theory is falsifiziert with the experimental test, then it must be rejected.

Nearly always fundamental physical theories have also crucial influence on our conception of the world.

Table of contents

necessity for the theory identification

theories new for the formulation gives it several reasons:

  • The problem is described in principle by the existing theories, is however too complicated, practical around itto compute.
That might be by far the most frequent case. In so a case no new fundamental theory, but an approximation theory is set up. For example in solid-state physics the large, but finite solid body is brought closer by an infinite solid body. Simplifiesthe equations substantially and leads for macroscopic bodies to negligible errors. If these errors are no longer negligible, then they can be usually considered by disturbance-theoretical methods.
  • Exist experimental data, which cannot be explained by the existing theories.
Thisis the most frequent cause for a new fundamental theory. For example quantum mechanics developed, in order to explain the unverstandenen phenomena of the black body radiation and later the photoelectric effect and the spectral lines from atoms to.
The theories are however generally enough in their explanation strength andtheir consequences the substantially beyond problems, because of which they were developed. Thus quantum mechanics explains, why the subject is firm and why the chemical elements itself so and not differently holds back, it is basis of the semiconductor physics and thus thatour conception of the world revolutionized entire modern electronics, and it fundamentally (so fundamentally that to today no agreement over the consequences for our conception of the world exists).
  • Exist several theories, which worked satisfactorily in past experiments, which do not fit however.
In this case for a theory one searches, which covers both previous theories as special cases. This e.g. was. with Einstein's general relativity theory the case: Newton's Gravitationstheorie (with instantaner action at a distance) did not fit special relativity theory (with the relativity of the simultaneousnessand the vacuum speed of light as maximum speed). General relativity theory supplies both the special relativity theory and special case of infinitesimal gravitation, and the Newton's Gravitationstheorie as special case of small gravitation and at the same time low speeds.
At present becomes after the standardization of the two large theories20. Century searched: General relativity theory and quantum mechanics.
  • The current theory can describe in principle the observed phenomena, but only, by putting a great many observation data in.
A goal of the new theory is it then, with less free parametersto get along. The more parameter one to put in must, the smaller is the force of expression of the theory. Extreme case is a theory, into which one puts so many parameters, as one receives data from it; this theory has at all no more force of expression, there itproblem-free to nearly arbitrary data to be adapted can.
Prime example was the transition from the geocentric to the heliozentrischen conception of the world. The Geozentriker could describe in principle the planet courses, only they had to put in more and more Epizykeln (and thus more and more observation parameter).Kepler however could describe the same planetary motion with only one handful parameters (per planet in each case the situation of the ellipse and the size of the shaft sections) with its heliozentrischen ellipses.

important subsections

beside it gives it interdisciplinary research with participation to theoretical physics, for instance the physical chemistry or elements of the chaos theory.

famous one theoreticalPhysicist

(see also: Physicist with the there detailed index)

literature

  • Landau/Lifschitz: Text book of theoretical physics Bd.1-10, Harri German publishing house
  • Arnold Sommerfeld: Lectures on theoretical physics Bd.1-6, Harri GermanPublishing house
  • walter Greiner: Theoretical physics, Harri German publishing house
  • Wolfgang Nolting: Basic course: Theoretical physics, Springer publishing house
  • hitting a corner hard Rebhan: Theoretical physics Bd.1&2, spectrum academic publishing house
  • Friedhelm Kuypers: Classical mechanics, Wiley VCH
  • Torsten flow brook: Theoretical physics, spectrum academic publishing house

see also

Web on the left of

Wikibooks: Text books about physics - learning and teaching materials
 

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