Συμμετρία



Συμμετρία
Μετασχηματισμοί

Συμμετρία
Μετασχηματισμοί

Συμμετρία

Συμμετρία

Συμμετρία




- Είναι μία Συμμετρία
Ετυμολογία[]
Η ονομασία "τοπική" σχετίζεται ετυμολογικά με τις λέξη "τόπος".
Ορισμός[]
In addition to global symmetries, which are almost always present in a physical theory, it is possible to have a "local" symmetry, in which the convention can be decided independent¬ly at every point in space and at every moment in time.
Although "local" may suggest something of more modest scope than a global symmetry, in fact the requirement of local symmetry places a far more stringent constraint on the construction of a theory.
- A global symmetry states that some law of physics remains invariant when the same transformation is applied everywhere at once.
- For a local symmetry to be observed the law of physics must retain its validity even when a different transformation takes place at each point in Space and Time.
Περιγραφή[]
In physics, a local symmetry is symmetry of some physical quantity, which smoothly depends on the point of the base manifold.
Such quantities can be for example
- an observable,
- a tensor or
- the Lagrangian of a theory.
A local symmetry is a symmetry arising from the action of an infinite dimensional Lie group (e.g SU(2) group)
If a symmetry is local in this sense, then one can apply a local transformation (resp. local gauge transformation), which means that the representation of the symmetry group is a function of the manifold and can thus be taken to act differently on different points of Spacetime.
The diffeomorphism group is a local symmetry and thus every geometrical or generally covariant theory (i.e. a theory whose equations are tensor equations, for example general relativity) has local symmetries.
Often the term local symmetry is specifically associated with local gauge symmetries in Yang-Mills theory (see also standard model) where the Lagrangian is locally symmetric under some compact Lie group.
Local gauge symmetries always come together with some bosonic gauge fields (like the photon or gluon field) which induce a force in addition to requiring conservation laws.[1]
Παραδείγματα[]
- General relativity has a local symmetry (general covariance, diffeomorphisms) which can be seen as generating the gravitational force.[2] Special relativity only has a global symmetry (Lorentz symmetry or more generally Poincare symmetry)
- There are many global symmetries (such as SU(2) of isospin symmetry) and local symmetries (like SU(2) of weak interactions) in particle physics. The standard model of particle physics consists of Yang-Mills Theories
- The symmetry group of Supergravity is a local symmetry, whereas supersymmetry is a global symmetry.
Υποσημειώσεις[]
- ↑ Kaku, Michio (1993). Quantum Field Theory: A Modern Introduction. New York: Oxford University Press. ISBN 0-19-507652-4.
- ↑ Πρότυπο:Cite document
Εσωτερική Αρθρογραφία[]
- αρμονία
- Βιολογική Συμμετρία
- Ολική Συμμετρία
- Ολική Βαθμιδική Συμμετρία
- Τοπική Βαθμιδική Συμμετρία
- Σημειακή Συμμετρία
- Αξονική Συμμετρία
- Επιπεδική Συμμετρία
- εμμετρία
- Χωρόχρονος
- Γενικευμένος Χωρόχρονος
- Φυσικό Πεδίο
- Global spacetime structure
- Local spacetime structure
- Gauge theory
- Gravitation
Βιβλιογραφία[]
Ιστογραφία[]
![]() ![]() |
---|
Αν και θα βρείτε εξακριβωμένες πληροφορίες "Οι πληροφορίες αυτές μπορεί πρόσφατα Πρέπει να λάβετε υπ' όψη ότι Επίσης, |
- Μην κάνετε χρήση του περιεχομένου της παρούσας εγκυκλοπαίδειας
αν διαφωνείτε με όσα αναγράφονται σε αυτήν
- Όχι, στις διαφημίσεις που περιέχουν απαράδεκτο περιεχόμενο (άσεμνες εικόνες, ροζ αγγελίες κλπ.)