II) Spontaneous Symmetry Breaking Flashcards
1
Q
What is spontaneous symmetry breaking?
A
When the Lagrangian is symmetric but the solutions (e.q. vacuum state) to the action being zero isn’t.
2
Q
Why is there no symmetry breaking in quantum mechanics?
A
Due to superposition (the wave function is continuous).
3
Q
What does the Goldstone Theorem state?
A
that if there is an exact continuous symmetry of the Hamiltonian or Lagrangian defining the system, and this is not a symmetry of the vacuum state (i.e. there is broken symmetry), then there must be at least one spin-zero massless particle called a Goldstone boson
