We consider the spontaneous breaking of translational symmetry and identify the associated Goldstone mode — a longitudinal phonon — in a holographic model with Bianchi VII helical symmetry. For the first time in holography, we observe the pinning of this mode after introducing a source for explicit breaking compatible with the helical symmetry of our setup. We study the dispersion relation of the resulting pseudo-Goldstone mode, uncovering how its speed and mass gap depend on the amplitude of the source and temperature. In addition, we extract the optical conductivity as a function of frequency, which reveals a metal-insulator transition as a consequence of the pinning.
|Journal||Journal of High Energy Physics|
|Publication status||Published - 1 Feb 2018|
Bibliographical noteFunding Information:
Article funded by SCOAP3.
© 2018, The Author(s).
- AdS-CFT Correspondence
- Holography and condensed matter physics (AdS/CMT)