Holographic fundamental matter in multilayered media

Abstract

We describe a strongly coupled layered system in 3+1 dimensions by means of a top-down D-brane construction. Adjoint matter is encoded in a large-N c stack of D3-branes, while fundamental matter is confined to (2 + 1)-dimensional defects introduced by a large-N f stack of smeared D5-branes. To the anisotropic Lifshitz-like background geometry, we add a single flavor D7-brane treated in the probe limit. Such bulk setup corresponds to a partially quenched approximation for the dual field theory. The holographic model sheds light on the anisotropic physics induced by the layered structure, allowing one to disentangle flavor physics along and orthogonal to the layers as well as identifying distinct scaling laws for various dynamical quantities. We study the thermodynamics and the fluctuation spectrum with varying valence quark mass or baryon chemical potential. We also focus on the density wave propagation in both the hydrodynamic and collisionless regimes where analytic methods complement the numerics, while the latter provides the only resource to address the intermediate transition

Brane nucleation instabilities in non-AdS/non-CFT

“…As the temperature is lowered, the disordered phase can become unstable towards the breaking of symmetries, either internal [15], spacetime [16,17], or both [18][19][20]. There is a whole zoo of ordered phases that include superfluids [15,[18][19][20][21][22], anisotropic states [23][24][25][26][27][28][29][30][31][32][33][34][35][36], striped phases , and even color superconducting phases [62][63][64][65][66][67].…”

Holographic Floquet states in low dimensions

“…However, we could adopt some approximation, as it is done in the smearing approach (see [41] for a review). Interestingly, the smeared backreacted D3-D5 background has been obtained in [42] (see also [43][44][45]) and one could try to generalize these results to the case in which an external rotating electric field is acting on the flavor brane.…”

Holographic spontaneous anisotropy

“…Since supersymmetry will be broken, it is to be expected that stable configurations do not admit an arbitrary distribution of smeared branes, but rather that it will be unique or very constrained, if it exists. In this work we have focused on duals to states with spontaneously broken isotropy, but our identification of the dual operator sourced by the branes as an axial current connects the multilayered solutions of [54][55][56] to the physics of Weyl semimetals (see, e.g., [85]), although in the last case the axial current is Abelian. It is clearly interesting to pursue this direction further.…”

“…The D5-branes are smeared along the transverse directions parallel to the D3-branes, in such a way that the resulting solution is homogeneous but anisotropic along one of the spatial directions of the field theory dual. Configurations of this type were previously constructed and studied in [54][55][56]. The main novelty in this work is that we allow the density of D5-branes to go to zero at the asymptotic boundary of space.…”

“…In systems with strongly correlated electrons, anisotropic nematic phases appear in the presence of magnetic fields in ultra-clean quantum Hall systems and in Sr 3 Ru 2 O 7 , and there is evidence that similar phases are present in iron-based and cuprate high T c superconductors (see [53] for a review on the topic). The application of holography to anisotropic and multilayered condensed matter systems has produced many interesting results [54][55][56].…”