Holographic Type II Goldstone bosons

Understand

The Goldstone theorem implies the appearance of an ungapped mode whenever a continuous global symmetry is spontaneously broken.

• In general it does not say anything about the precise form of the dispersion relation nor does it imply that there is one massless mode for each broken symmetry generator.
• It is a well-established fact that even for relativistic field theories in the presence of a chemical potential Goldstone modes with quadratic dispersion relation, the type II Goldstone bosons, appear in the spectrum.
• We develop two holographic models that feature type II Goldstone modes as part of the quasinormal mode spectrum.