Spontaneous Symmetry Breaking
An interesting feature can occur if m2 happens to be negative, but with λ positive. In this case, the vacuum consists of two lowest-energy states, each of which spontaneously breaks the Z2 global symmetry of the original theory. This leads to the appearance of interesting collective states like domain walls. In the O(2) theory, the vacua would lie on a circle, and the choice of one would spontaneously break the O(2) theory. A continuous broken symmetry leads to a Goldstone boson. This type of spontaneous symmetry breaking is the essential component of the Higgs mechanism.
Read more about this topic: Quartic Interaction
Famous quotes containing the words spontaneous, symmetry and/or breaking:
“Our spontaneous action is always the best. You cannot, with your best deliberation and heed, come so close to any question as your spontaneous glance shall bring you.”
—Ralph Waldo Emerson (1803–1882)
“What makes a regiment of soldiers a more noble object of view than the same mass of mob? Their arms, their dresses, their banners, and the art and artificial symmetry of their position and movements.”
—George Gordon Noel Byron (1788–1824)
“The defects and faults of the mind are like wounds in the body; after all imaginable care has been taken to heal them up, still there will be a scar left behind, and they are in continual danger of breaking the skin and bursting out again.”
—François, Duc De La Rochefoucauld (1613–1680)