In science, an effective theory is a scientific theory which proposes to describe a certain set of observations, but explicitly without the claim or implication that the mechanism used by the theory has a direct counterpart in the actual causes of the observed phenomena to which the theory is fitted. That means that the theory proposes to model a certain effect, without proposing to model adequately any of the causes which contribute to the effect.
For example, effective field theory is a method used to describe physical theories when there is a hierarchy of scales. Effective field theories in physics can include quantum field theories in which the fields are treated as fundamental, and effective theories describing phenomena in solid-state physics. For instance, the BCS theory of superconduction treats vibrations of the solid-state lattice as a "field" (i.e. without claiming that there is really a field), with its own field quanta, known as phonons. Such "effective particles" derived from effective fields are also known as quasiparticles.
In a certain sense, quantum field theory, and any other currently known physical theory, could be described as "effective", as in being the "low energy limit" of an as-yet unknown "Theory of Everything".[1]
^c.f. Stamatescu, Ion-Olimpiu; Seiler, Erhard (2007). Approaches to Fundamental Physics: An Assessment of Current Theoretical Ideas. Lecture Notes in Physics. Vol. 721. Springer. p. 47. ISBN 978-3-540-71115-5.
In science, an effectivetheory is a scientific theory which proposes to describe a certain set of observations, but explicitly without the claim or implication...
physics, an effective field theory is a type of approximation, or effectivetheory, for an underlying physical theory, such as a quantum field theory or a statistical...
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Other effectivetheories are heavy quark effectivetheory (which expands around heavy quark mass near infinity), and soft-collinear effectivetheory (which...
In quantum chromodynamics, heavy quark effectivetheory (HQET) is an effective field theory describing the physics of heavy (that is, of mass far greater...
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based on NJL model results). For each phase, they then write down an effectivetheory for the low-energy excitations, in terms of a small number of parameters...
and computability theory, an effective method or effective procedure is a procedure for solving a problem by any intuitively 'effective' means from a specific...
is motivated by the low energy effectivetheory of the chiral spin states which is a topological quantum field theory (TQFT). New quantum numbers, such...
application to the solution of Diophantine equations, results in number theory have been scrutinised more than in other branches of mathematics to see...
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to topological field theory. In condensed matter physics, topological quantum field theories are the low-energy effectivetheories of topologically ordered...
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realized in these results that the effective scale can be arbitrarily taken as μ, and can vary to define the theory at any other scale: g ( κ ) = G − 1...
Renormalization is a collection of techniques in quantum field theory, statistical field theory, and the theory of self-similar geometric structures, that are used...
computability theory overlaps with proof theory and effective descriptive set theory. Basic questions addressed by computability theory include: What...
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