The three decoupled quantum field
theories (with similar "symmetry" characterisics), the plasma dynamics theories, as well as the two theories of
relativity operate with different mathematical concepts. Those concepts were
developed by a step by step approach, which started 1900, when Max Planck
introduced the theory of „quanta with specific energies“ to explain „radiation“
effects. The consequences of
this step-by-step development process resulted
into
- paradoxes (from a
natural science and common sense perspective) with respect to contradicting predictions (e.g. the wave-particle dualism)
- paradoxes (from a mathematics perspective) having two different mathematical models explaining the same phenomenon by different physical causes (e.g. linear and nonlinear Landau damping)
The step-by-step development process of physical theories generated the following paradigm of physics,
(DeP) p. 551:
Physics is scale dependent and decoupling
1. Physics is scale dependent
and at each scale
there are different degrees of freedom and different
dynamics. Therefore, at each scale level to be studied, there is the need
for a different theory (e.g. classical continuum mechanics, theory of granular
structure, nucleus + electronic cloud, nuclear physics, QED, free-electron
theory, modelling, e.g. the properties of metals, semiconductors, and
insulators) to describe the behavior of the considered physical system
depending on a scale (of energies, distances, momenta, etc.). For example, in
quantum field theory, the dependence of the behavior on the scale is often expressed
mathematically by the fact that in order to regularize (i.e. render finite)
Feynman diagram integrals one must introduce auxiliary scales, cutoffs, etc.
The effect of these choices on the physics is encoded into the renormalization
group equation. This equation then becomes an important tool for the study of
physical theories.
2. Physics at large scale decouples from
the physics at a smaller scale
when passing from a smaller scale to a
larger scale irrelevant degrees of freedom are averaged over. Mathematically
this means that they become integration variables and thus disappear.
3. The different scales - In classical mechanics one deals with
three scales according to its three basic measurements: distance D, time T, mass M
- in non-relativistic quantum theory and
classical relativity it has two scales: D & T resp. D & M
(mass
M can be expressed through T & D using the Planck constant resp. T can be
expressed via D using the speed of light)
- in relativistic quantum theory there is
only one scale: distance D.