Question

What is phase symmetry?

Answer 1

Consider a particle P described by a chronologically ordered chain of events where each orbital cycle Ω can be expressed as a pair of events

Ω={P∘,P∙}

that are out of phase with each other so that

δθ(P∘)=−δθ(P∙)=±1

Then P∘ and P∙ are called phase components of P. If these two sets are composed from the same selection of quarks, then a description of the whole cycle Ω is unaffected if there is any confusion or mix-up about the sign of the phase. This robust indifference to the phase is useful, so we give particles like this a special name. Definition: if

P∘=P∙

then we say that P has phase symmetry. The most important examples of particles with phase symmetry are protons and electrons in their ground-states. So it is possible to make descriptions of protons and electrons that ignore the phase. Alternatively, if P∘=P∙¯¯¯¯¯ then we say that P has phase anti-symmetry.

sun.png Sensory interpretation: when the phase indicates whether an event is diurnal or nocturnal, then indifference to phase means that a description does not depend on whether it is day or night. Physicists in different time-zones can work together in considering particles like protons and electrons.





originally posted at :
http://mechanics.wikidot.com/phase-symmetry