renormalisointipiste

Renormalisointipiste, also known as a renormalization scale, is a concept that arises in quantum field theory. It is an arbitrary energy scale or length scale introduced during the process of renormalization. Renormalization is a systematic procedure used to handle infinities that appear in calculations involving quantum field theories, particularly when considering interactions at very small distances or high energies.

The values of physical quantities, such as particle masses and coupling constants, are found to depend on the renormalization scale. This dependence reflects the fact that the effective strength of interactions changes with the energy at which they are probed. For instance, at high energies, quantum fluctuations can "dress" a particle, effectively increasing its interaction strength. Conversely, at low energies, these fluctuations can screen the interaction.

The choice of renormalization scale is arbitrary, meaning that physical observables, which are the quantities that can be experimentally measured, must be independent of this choice. This independence is often expressed through the renormalization group equations. These equations describe how the parameters of a theory evolve as the renormalization scale is changed. The existence of a consistent physical prediction, independent of the chosen scale, is a crucial aspect of a well-defined quantum field theory. Essentially, the renormalization scale acts as a placeholder for the infinite number of quantum corrections, and its arbitrary nature is absorbed into the redefinition of physical parameters.