Implications of relativity on nonrelativistic Goldstone theorems: gapped excitations at finite charge density.
Phys Rev Lett
; 110(1): 011602, 2013 Jan 04.
Article
en En
| MEDLINE
| ID: mdl-23383776
ABSTRACT
We adapt the Goldstone theorem to study spontaneous symmetry breaking in relativistic theories at finite charge density. It is customary to treat systems at finite density via nonrelativistic Hamiltonians. Here, we highlight the importance of the underlying relativistic dynamics. This leads to seemingly new results whenever the charge in question is spontaneously broken and does not commute with other broken charges. We find that that the latter interpolate gapped excitations. In contrast, all existing versions of the Goldstone theorem predict the existence of gapless modes. We derive exact nonperturbative expressions for their gaps, in terms of the chemical potential and of the symmetry algebra.
Buscar en Google
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos