mitteparametralisation

Mitteparametralisation is a concept within theoretical physics, particularly in the context of effective field theories. It refers to a process or situation where the parameters of a theory are not treated as fundamental constants but rather as quantities that themselves depend on the energy scale or other underlying physics. This dependence arises when the theory is an approximation of a more fundamental theory and its parameters are effectively "averaged" or "integrated out" from the more fundamental degrees of freedom.

In simpler terms, imagine a simplified model that describes a phenomenon. Mitteparametralisation suggests that the numbers used in this simplified model aren't truly fixed. Instead, their values might change depending on how closely you look at the phenomenon or the specific energy regime you are considering. This is analogous to how the properties of a material can appear different at macroscopic versus microscopic scales.

The idea is closely related to the Renormalization Group (RG) flow, which describes how physical parameters change with energy scale. In RG, parameters are said to "run." Mitteparametralisation can be seen as a specific manifestation or consequence of this running behavior, where the effective parameters of the simplified theory are determined by the physics at a different, often higher, energy scale. It acknowledges that effective theories are not perfect descriptions but rather useful approximations whose parameters are constrained by the broader physical landscape. Understanding mitteparametralisation is crucial for constructing consistent and predictive effective field theories.