2000 character limit reached
Multicritical Symmetry Breaking and Naturalness of Slow Nambu-Goldstone Bosons (1308.5967v2)
Published 27 Aug 2013 in hep-th, cond-mat.str-el, cond-mat.supr-con, gr-qc, and hep-ph
Abstract: We investigate spontaneous global symmetry breaking in the absence of Lorentz invariance, and study technical Naturalness of Nambu-Goldstone (NG) modes whose dispersion relation exhibits a hierarchy of multicritical phenomena with Lifshitz scaling and dynamical exponents $z>1$. For example, we find NG modes with a technically natural quadratic dispersion relation which do not break time reversal symmetry and are associated with a single broken symmetry generator, not a pair. The mechanism is protected by an enhanced `polynomial shift' symmetry in the free-field limit.