Transverse collective modes in interacting holographic plasmas
Abstract
We study in detail the transverse collective modes of simple holographic models in presence of electromagnetic Coulomb interactions. We render the Maxwell gauge field dynamical via mixed boundary conditions, corresponding to a double trace deformation in the boundary field theory. We consider three different situations: (i) a holographic plasma with conserved momentum, (ii) a holographic (dirty) plasma with finite momentum relaxation and (iii) a holographic viscoelastic plasma with propagating transverse phonons. We observe two interesting new features induced by the Coulomb interactions: a mode repulsion between the shear mode and the photon mode at finite momentum relaxation, and a propagationtodiffusion crossover of the transverse collective modes induced by the finite electromagnetic interactions. Finally, at large charge density, our results are in agreement with the transverse collective mode spectrum of a charged Fermi liquid for strong interaction between quasiparticles, but with an important difference: the gapped photon mode is damped even at zero momentum. This property, usually referred to as anomalous attenuation, is produced by the interaction with a quantum critical continuum of states and might be experimentally observable in strongly correlated materials close to quantum criticality, e.g. in strange metals.
 Publication:

Journal of High Energy Physics
 Pub Date:
 April 2020
 DOI:
 10.1007/JHEP04(2020)106
 arXiv:
 arXiv:1912.07321
 Bibcode:
 2020JHEP...04..106B
 Keywords:

 Holography and condensed matter physics (AdS/CMT);
 Gaugegravity correspondence;
 High Energy Physics  Theory;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 v2: matching the version published in JHEP