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Y-system for γ-deformed ABJM Theory

Hui-Huang Chen; Peng Liu; Jun-Bao WuSubjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

We investigate the integrable aspects of the planar -deformed ABJM theory and propose the twisted asymptotic Bethe ansatz equations. A more general method through a twisted generating functional is discussed, based on which, the asymptotic large L solution of Y-system is modi ed in order to match the asymptotic Bethe ansatz equations. Several applications of our method in the sl(2)-like sector and some important examples in -deformed ABJM are presented as well. |

Note on the butterfly effect in holographic superconductor models

Yi Ling; Peng Liu; Jian-Pin WuSubjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

In this note we remark that the butterfly effect can be used to diagnose the phase transition of superconductivity in a holographic framework. Speci cally, we compute the butterfly velocity in a charged black hole background as well as anisotropic backgrounds with Q-lattice structure. In both cases we nd its derivative to the temperature is discontinuous at critical points. We also ropose that the butterfly velocity can signalize the occurrence of thermal phase transition in general holographic models. |

Subjects: Geosciences >> Space Physics

The paper presents a method estimating the HY-2A altimeter ultra stable oscillator (USO) drift with a reconstructive transponder. The frequency of the USO of the in-orbit altimeter changes with age, and a bias between the actual frequency and the nominal one exists. The USO bias contributes a portion of the altimeter range drift. The HY-2A altimeter transmits signals at a fixed time interval during calibration, and the actual interval between adjacent altimeter transitions, which is controlled by the USO, is different from the nominal one due to the USO drift. The reconstructive transponder measures the arrival times of the altimeter transmitted signals accurately with the atomic clock. The drift of the USO on-board the HY-2A altimeter can be estimated accurately by using the ranges from the reconstructive transponder and the HY-2A altimeter. The USO drifts of around 40 cm/year are presented. Furthermore, the multi-mission crosscalibration provides preliminary validation of HY-2A altimeter USO drift. |

submitted time
2016-12-26
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Subjects: Geosciences >> Space Physics

A reconstructive transponder has been utilized for the in-orbit calibration campaign of the HY-2A radar altimeter since March 2012. The precision of final calibration result is influenced by echo signal's quality in the HY-2A altimeter's range window. As an indicator of the signal's quality, echo signal dwell time is analyzed considering its influence on signal quality and its uncertainty. In HY-2A altimeter calibration, the echo signal dwell time is determined by the radial orbit prediction uncertainty and the real-time signal processing mechanism of the reconstructive transponder. The real-time signal processing mechanism of the reconstructive transponder utilizes some incoming signal samples without sending echo signals before transmitting. Comparing with the length of the HY-2A altimeter's range window, the radial orbit prediction uncertainty is large. Large radial orbit prediction uncertainty and signal processing mechanism of the reconstructive transponder are two main factors that limit the echo signal dwell time in HY-2A altimeter calibration. Finally, approaches for increasing echo signal dwell time are briefly proposed. |

submitted time
2016-12-26
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A novel insulator by holographic Q-lattices

Yi Ling; Peng Liu; Jian-Pin WuSubjects: Physics >> Nuclear Physics

We construct a bulk geometry with Q-lattice structure, which is implemented by two gauge fields and a coupling between the lattice and the Maxwell field. This gravity dual model can describe a novel insulator which exhibits some key features analogous to Mott insulator. In particular, a hard gap in insulating phase as well as vanishing DC conductivity can be simultaneously achieved. In addition, we discuss the non-Drude behavior of the optical conductivity in low frequency region in insulating phase, which exhibits some novel characteristics different from ordinary Mott insulator. |

Building a doped Mott system by holography

Yi Ling; Peng Liu; Chao Niu; Jian-Pin Wu; Zhuo-Yu XianSubjects: Physics >> Nuclear Physics

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. |

Holographic Entanglement Entropy Close to Quantum Phase Transitions

Yi Ling; Peng Liu; Chao Niu; Jian-Pin Wu; Zhuo-Yu XianSubjects: Physics >> Nuclear Physics

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. |

Holographic Metal-Insulator Transition in Higher Derivative Gravity

Yi Ling; Peng Liu; Jian-Pin Wu; Zhenhua ZhouSubjects: Physics >> Nuclear Physics

We introduce a Weyl term into the Einstein-Maxwell-Axion theory in four dimensional spacetime. Up to the first order of the Weyl coupling parameter?γ, we construct charged black brane solutions without translational invariance in a perturbative manner. Among all the holographic frameworks involving higher derivative gravity, we are the first to obtain metal-insulator transitions (MIT) when varying the system parameters at zero temperature. Furthermore, we study the holographic entanglement entropy (HEE) of strip geometry in this model and find that the second order derivative of HEE with respect to the axion parameter exhibits maximization behavior near quantum critical points (QCPs) of MIT. It testifies the conjecture in?1502.03661?and?1604.04857?that HEE itself or its derivatives can be used to diagnose quantum phase transition (QPT). |

Characterization of Quantum Phase Transition using Holographic Entanglement Entropy

Yi Ling; Peng Liu; Jian-Pin WuSubjects: Physics >> Nuclear Physics

The entanglement exhibits extremal or singular behavior near quantum critical points (QCPs) in many condensed matter models. These intriguing phenomena, however, still call for a widely accepted understanding. In this letter we study this issue in holographic framework. We investigate the connection between the holographic entanglement entropy (HEE) and the quantum phase transition (QPT) in a lattice-deformed Einstein-Maxwell-Dilaton theory. Novel backgrounds exhibiting metal-insulator transitions (MIT) have been constructed in which both metallic phase and insulating phase have vanishing entropy density in zero temperature limit. We find that the first order derivative of HEE with respect to lattice parameters exhibits extremal behavior near QCPs. We propose that it would be a universal feature that HEE or its derivatives with respect to system parameters can characterize QPT in a generic holographic system. Our work opens a window for understanding the relation between entanglement and the QPT from holographic perspective. |

Pseudo-gap phase and duality in a holographic fermionic system with dipole coupling on Q-lattice

Yi Ling(1; Peng Liu; Chao Niu; Jian-Pin Wu(2Subjects: Physics >> Nuclear Physics

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?pspace 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. |

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