Subjects: Physics >> Nuclear Physics submitted time 2016-09-14
Abstract： We construct a holographic model in the framework of Q-lattices whose dual exhibits metal-insulator transitions. By introducing an interacting term between the Q-lattice and the electromagnetic field in bulk geometry, we find such kind of transition can be Mott-like. The evidences are presented as follows. i) The transition from a metallic phase to an insulating phase occurs when the lattice constant becomes larger. ii) A hard gap in the insulating phase can be manifestly observed in the optical conductivity. Nevertheless, in the zero temperature limit this model exhibits novel metallic behavior, featured by a gap as well as a zero-frequency mode with tiny spectral weight. It implies that our model is dual to a doped Mott system in one dimension where umklapp scattering is frozen at zero temperature. The similarity between this model and some organic linear chain conductors is briefly discussed.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2016-09-13
Abstract： We investigate the holographic entanglement entropy (HEE) of a strip geometry in four dimensional Q-lattice backgrounds, which exhibit metal-insulator transitions in the dual field theory. Remarkably, we find that the HEE always displays a peak in the vicinity of the quantum critical points. Our model provides the first direct evidence that the HEE can be used to characterize the quantum phase transition (QPT). We also conjecture that the maximization behavior of HEE at quantum critical points would be universal in general holographic models.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2016-08-31
Abstract： We classify the different phases by the "pole-zero mechanism" for a holographic fermionic system which contains a dipole coupling with strength爌爋n a Q-lattice background. A complete phase structure in爌space can be depicted in terms of Fermi liquid, non-Fermi liquid, Mott phase and pseudo-gap phase. In particular, we find that in general the region of the pseudo-gap phase in爌爏pace is suppressed when the Q-lattice background is dual to a deep insulating phase, while for an anisotropic background, we have an anisotropic region for the pseudo-gap phase in爌爏pace as well. In addition, we find that the duality between zeros and poles always exists regardless of whether or not the model is isotropic.
Peer Review Status:Awaiting Review
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