Alternating current conductivity and superconducting properties of the holographic effective theory

Abstract

We construct a holographic effective superconducting theory by considering a special gauge-axion higher derivative term. The gauge-axion coupling results in the transport behavior similar to the vortex response in the dual boundary field theory leading to non-Drude behavior of alternating current (AC) conductivity at the weak momentum dissipation. With the momentum dissipation increasing, a dip exhibits in the AC conductivity at low frequency. It is thought to be the result of a combination of the strong momentum dissipation and the gauge-axion coupling. In the superconducting phase, this gauge-axion coupling also plays a key role leading to a more evident gap at the low frequency conductivity. In addition, we also study the combined effects of the strength of momentum dissipation and various couplings among the gauge field, axion fields and the complex scalar field.

Transport properties of a $3$-dimensional holographic effective theory with gauge-axion coupling

“…We find that when J is small, the system is metallic for all k. However, when J is large, there is a MIT that the system changes from metallic phase to insulating phase with k increasing. It is different from that of the 4-dimensional case, where for fixed gauge-axion coupling, we cannot observe a MIT when changing the strength of momentum dissipation [34][35][36][37]. Further, we show the thermal conductivity κ at zero electric field as the function of T with different J and k in Fig.…”

“…Following previous works of 4-dimensional Einstein-Maxwell-axion model with gaugeaxion coupling [34][35][36][37][38], we implement a 3-dimensional holographic effective model with gauge-axion coupling, whose action is…”

Transverse Goldstone mode in holographic fluids with broken translations

“…5 Since they do not feature wave or diffusive behaviors, as was verified in [67] with the field theory method that they do not appear as poles in correlators of physical observables. Moreover, the impact of the vortex on charge transport was also be investigated in holographic models with the same gauge-axion coupling [68].…”