Difference between revisions of "Effective theories"
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| + | In science, an '''effective theory''' is a [[scientific theory]] which proposes to describe a certain set of [[Experiment|observations]], but explicitly without the claim or implication that the mechanism employed in the theory has a direct counterpart in the actual causes of the observed phenomena to which the theory is fitted. That means, the theory proposes to model a certain ''effect'', without proposing to adequately model any of the ''causes'' which contribute to the effect. | ||
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| + | For example, [[effective field theory]] is a set of tools 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 (physics)|field]]" (i.e. without claiming that there is "[[reality|really]]" a field), with its own field quanta, called [[phonon]]s. Such "effective particles" derived from effective fields are also known as [[quasiparticle]]s. | ||
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| + | 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]]".<ref>c.f. {{cite book |first=Ion-Olimpiu |last=Stamatescu |first2=Erhard |last2=Seiler |title=Approaches to Fundamental Physics: An Assessment of Current Theoretical Ideas |series=Lecture Notes in Physics |volume=vol. 721 |publisher=Springer |year=2007 |isbn=978-3-540-71115-5 |page=47 }}</ref> | ||
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There are many effective theories which capture the symmetries of the quantum chromodynamics and are easier to handle. Examples are | There are many effective theories which capture the symmetries of the quantum chromodynamics and are easier to handle. Examples are | ||
* [https://en.wikipedia.org/wiki/Nambu–Jona-Lasinio_model Nambu Jona Lasinio model] | * [https://en.wikipedia.org/wiki/Nambu–Jona-Lasinio_model Nambu Jona Lasinio model] | ||
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* [https://en.wikipedia.org/wiki/Chiral_perturbation_theory Chiral perturbation theory] | * [https://en.wikipedia.org/wiki/Chiral_perturbation_theory Chiral perturbation theory] | ||
and others... | and others... | ||
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| + | ==See also== | ||
| + | {{Div col|colwidth=20em}} | ||
| + | *[[Effective mass (solid-state physics)]] | ||
| + | *[[Emergence]] | ||
| + | *[[Empirism]] | ||
| + | *[[Epistemology]] | ||
| + | *[[Heuristics]] | ||
| + | *[[Scientific method]] | ||
| + | *[[Turing test]] | ||
| + | {{Div col end}} | ||
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| + | ==References== | ||
| + | {{reflist}} | ||
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| + | [[Category:Scientific theories]] | ||
Latest revision as of 07:58, 10 May 2021
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 employed in the theory has a direct counterpart in the actual causes of the observed phenomena to which the theory is fitted. That means, the theory proposes to model a certain effect, without proposing to adequately model any of the causes which contribute to the effect.
For example, effective field theory is a set of tools 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, called 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".<ref>c.f. Template:Cite book</ref>
There are many effective theories which capture the symmetries of the quantum chromodynamics and are easier to handle. Examples are
and others...
See also
- Effective mass (solid-state physics)
- Emergence
- Empirism
- Epistemology
- Heuristics
- Scientific method
- Turing test
