RSS - Posts- Neother Theorem is the Lagrangian form of Ehrenfest Theorem which is in Hamiltonian form. There are two correspondences (not very exact) :
- The Lagrangian is invariant under some symmetry corresponds to the Hamiltonian commutes with some operator (symmetry group’s generator)
- The Neother charge is a time constant corresponds to the expectation value of the symmetry operator is a time constant, actually, the Neother charge is just the expectation value of the generator.
- From Kaplan’s Colloquium (11.29):
- EW theory must break down because of 4W interaction, just like 4 fermion interaction must break down, which is caused by violating unitarity. And the solution is similar, 4 fermion need a gauge boson to change 4 vertex to 3 vertex, and 4W need a Higgs (or other new particle?) to change 4 vertex to 3 vertex.
- MSSM has more than 100 parameters! ( I heard this for the first time)
- Higgs mechnism can be traced back to Schwinger, who proved that massive gauge bosons do not necessarily violate gauge symmetry, by introducing a scalar field, but did not mention symmetry breaking. And there were other guys’ work following this, showing symmetry breaking, until Higgs pointed out the existence of a scalar particle following the referee(highly suspected to be Schwinger)’s suggestion. So came the name ‘Higgs particle’.
- From Tom’s seminar (12.3)
SUSY can be broken explicitly at UV (elementary sector) but emerges accidentally at IR (composite sector). The symmetries at lower energy are more than that at higher energy, which seems blizzard, but not. From 5D view, IR have more gauge symmetry and so more degrees of freedom just because UV and IR are two vacuums separated by the bulk (or domain wall); from 4D view, the different symmetries become global symmetry so it will not take more degrees of freedom, and the low energy global symmetry is always broken at high energy. (Because of gravity)
