We classify the different phases by the “pole-zero mechanism” for a holographic fermionic system which contains a dipole coupling with strength p on a Q-lattice background. A complete phase structure in p space can ...We classify the different phases by the “pole-zero mechanism” for a holographic fermionic system which contains a dipole coupling with strength p on a Q-lattice background. A complete phase structure in p 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 p space 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 p space as well. In addition, we find that the duality between zeros and poles always exists regardless of whether or not the model is isotropic.展开更多
We construct a holographic superconductor model, based on a gravity theory, which exhibits novel metal-insulator transitions. We investigate the condition for the condensation of the scalar field over the parameter sp...We construct a holographic superconductor model, based on a gravity theory, which exhibits novel metal-insulator transitions. We investigate the condition for the condensation of the scalar field over the parameter space, and then focus on the superconductivity over the insulating phase with a hard gap, which is supposed to be Mott-like. It turns out that the formation of the hard gap in the insulating phase benefits the superconductivity.This phenomenon is analogous to the fact that the pseudogap phase can promote the pre-pairing of electrons in high Tccuprates. We expect that this work can shed light on understanding the mechanism of high Tcsuperconductivity from the holographic side.展开更多
This is a pedagogical review on TT^(-)deformation of two dimensional quantum field theories.It is based on three lectures which the author gave at ITP-CAS in December 2018.This review consists of four parts.The first ...This is a pedagogical review on TT^(-)deformation of two dimensional quantum field theories.It is based on three lectures which the author gave at ITP-CAS in December 2018.This review consists of four parts.The first part is a general introduction to TT^(-)deformation.Special emphasises are put on the deformed classical Lagrangian and the exact solvability of the spectrum.The second part focuses on the torus partition sum of the TT^(-)/JT^(-)deformed conformal field theories and modular invariance/covariance.In the third part,different perspectives of TT^(-)deformation are presented,including its relation to random geometry,2D topological gravity and holography.We summarize more recent developments until January 2021 in the last part.展开更多
基金Supported by National Natural Science Foundation of China(11275208,11305018,11178002)Jiangxi Young Scientists(Jing-GangStar)Progran555 Talent Project of Jiangxi Province,Liaoning Excellent Talents in University(LJQ2014123)
文摘We classify the different phases by the “pole-zero mechanism” for a holographic fermionic system which contains a dipole coupling with strength p on a Q-lattice background. A complete phase structure in p 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 p space 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 p space as well. In addition, we find that the duality between zeros and poles always exists regardless of whether or not the model is isotropic.
基金Supported by Natural Science Foundation of China(11575195,11775036,11305018)Y.L.also acknowledges the support from Jiangxi young scientists(Jing Gang Star)program+1 种基金555 talent project of Jiangxi Provincesupported by Natural Science Foundation of Liaoning Province(201602013)
文摘We construct a holographic superconductor model, based on a gravity theory, which exhibits novel metal-insulator transitions. We investigate the condition for the condensation of the scalar field over the parameter space, and then focus on the superconductivity over the insulating phase with a hard gap, which is supposed to be Mott-like. It turns out that the formation of the hard gap in the insulating phase benefits the superconductivity.This phenomenon is analogous to the fact that the pseudogap phase can promote the pre-pairing of electrons in high Tccuprates. We expect that this work can shed light on understanding the mechanism of high Tcsuperconductivity from the holographic side.
基金It is a pleasure to thank Ofer Aharony,Shouvik Datta,Amit Giveon and David Kutasov for collaborations on the relevant projects that lead to this review.I thank Gang Yang for kind invitation and hospitality at ITP-CAS.Tm also indebted to Luis Apolo,Wei Li,Pujian Mao,Wei Song,Junbao Wu and Gang Yang for various helpful discussions.Many thanks to Alex Belin,Shouvik Datta,Amit Giveon,Madalena Lemos,Kostas Siampos,Wei Song,Roberto Tateo,Junbao Wu and Gang Yang for valuable feedbacks.
文摘This is a pedagogical review on TT^(-)deformation of two dimensional quantum field theories.It is based on three lectures which the author gave at ITP-CAS in December 2018.This review consists of four parts.The first part is a general introduction to TT^(-)deformation.Special emphasises are put on the deformed classical Lagrangian and the exact solvability of the spectrum.The second part focuses on the torus partition sum of the TT^(-)/JT^(-)deformed conformal field theories and modular invariance/covariance.In the third part,different perspectives of TT^(-)deformation are presented,including its relation to random geometry,2D topological gravity and holography.We summarize more recent developments until January 2021 in the last part.
