Sanjiang College

Nanjing, China

Sanjiang College

Nanjing, China
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Jiang J.-J.,Sanjiang College | Liu Y.-J.,Yangzhou University | Tang F.,Yangzhou Polytechnic Institute | Yang C.-H.,Nanjing University of Information Science and Technology | Sheng Y.-B.,Nanjing University of Posts and Telecommunications
Physica B: Condensed Matter | Year: 2015

By using the analytical coupled cluster method, the numerical exact diagonalization method, and the numerical density matrix renormalization group method, we investigated the properties of the one-dimensional sawtooth chain. The results of the coupled cluster method based on Néel state demonstrate that the ground state is in the quasi-Néel-long-range order state when α<αc1. The translational symmetry of the ground state varies and the ground state evolves from the quasi-Néel-long-range order state to the dimerized state at the critical point αc1. The dimerized state is stable in the intermediate parameter region and vanishes at another critical point αc2. The results drawn from the exact diagonalization show that the precise critical points αc1 and αc2can be determined by using the spin stiffness fidelity susceptibility and spin gap separately. We compared the results obtained by using the coupled cluster method based on canted state with those obtained based on spiral state, and found that the ground state of the sawtooth chain is in the quasi-canted state if α>αc2. The results of the coupled cluster method and the density matrix renormalization group method both disclose that the type of the quantum phase transition occurring at αc2 belongs to the first-order transition. © 2015 Elsevier B.V.


Jiang J.J.,Sanjiang College | Liu Y.J.,Yangzhou University | Tang F.,Yangzhou Polytechnic Institute | Yang C.H.,Nanjing University of Information Science and Technology
European Physical Journal B | Year: 2011

By using the method of density-matrix renormalization group, the reduced fidelity and entanglement in the one-dimensional bond-alternating S = 1 Heisenberg chain are investigated. The results demonstrate that the quantum phase transition from the Haldane phase to the dimer phase can be characterized by the reduced fidelity and the first derivation of the entanglement entropy. Through the finite-size scaling, the critical point and the critical exponent of the correlation length are obtained accurately. © 2011 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Jiang J.-J.,Sanjiang College | Liu Y.-J.,Yangzhou University | Tang F.,Yangzhou Polytechnic Institute | Yang C.-H.,Nanjing University of Information Science and Technology
European Physical Journal B | Year: 2011

By using the method of exact diagonalization, we investigate the quantum correlation measured by quantum discord of the dimerized spin chain at both zero and finite temperatures. The results disclose that the quantum discord is robust at any finite parameter α and temperature T, in contrast to entanglement which shows a sudden death when the parameter α or the temperature T reaches a critical point. At finite temperature, it is interesting to find that the quantum discord QD 2i-1, 2i can increase with temperature T no matter if the entanglement EoF 2i-1, 2i exists or not. The research on the relation between the quantum discord and the quantum phase transition in the dimerized spin chain indicates that the transition can be characterized by the first derivation of the quantum discord at zero and low temperatures. © 2011 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Jiang J.-J.,Sanjiang College | Liu Y.-J.,Yangzhou University | Tang F.,Yangzhou Polytechnic Institute | Yang C.-H.,Nanjing University of Information Science and Technology
Physica B: Condensed Matter | Year: 2011

We investigated the properties of the spin-1/2 ferromagneticantiferromagneticantiferromagnetic alternating Heisenberg chain using the spin-wave theory. The spin-wave excitation spectra, the sublattice magnetizations and the local bond energies of the model are calculated to be compared with the corresponding properties of the mixed spin (1, 1/2) chain for a range of α. The results demonstrate that all the properties show similar behaviours in the small α limit, so the properties of the mixed spin (1, 1/2) chain can be described using the spin-1/2 ferromagneticantiferromagneticantiferromagnetic alternating Heisenberg chain. © 2010 Elsevier B.V. All rights reserved.


Jiang J.-J.,Sanjiang College | Liu Y.-J.,Yangzhou University | Tang F.,Yangzhou Polytechnic Institute | Yang C.-H.,Nanjing University of Information Science and Technology
Journal of the Physical Society of Japan | Year: 2015

By the analytical coupled cluster method (CCM), we study both the ground state and lowest-lying excited-state properties of the alternating bond diamond chain. The numerical exact diagonalization (ED) method is also applied to the chain to verify the accuracy of CCM results. The ED results show that the ground-state phase diagram contains two exact spin cluster solid ground states, namely, the tetramer-dimer (TD) state and dimer state, and the ferrimagnetic longrange- ordered state. We prove that the two exact spin cluster solid ground states can both be formed by CCM. Moreover, the exact spin gap in the TD state can be obtained by CCM. In the ferrimagnetic region, we find that the CCM results for some physical quantities, such as the ground-state energy, the sublattice magnetizations, and the antiferromagnetic gap, are comparable to the results obtained by numerical methods. The critical line dividing the TD state from the ferrimagnetic state is also given by CCM and is in perfect agreement with that determined by the ED method. © 2015 The Physical Society of Japan.


Jiang J.-J.,Sanjiang College | Tang F.,Yangzhou Polytechnic Institute | Yang C.-H.,Nanjing University of Information Science and Technology
Journal of the Physical Society of Japan | Year: 2015

By using the coupled cluster method (CCM), the numerical exact diagonalization (ED) method, and the numerical density matrix renormalization group (DMRG) method, we investigated the properties of the one-dimensional Heisenberg chain with alternating antiferromagnetic and ferromagnetic next nearest neighbor interactions. In the classical limit, the ground state is in the collinear Neel state if α < 1/2, while for α > 1/2 there is an noncollinear canted state. For the quantum case, we found that, although the classical Neel state is absent, the canted state exists if the frustration parameter α exceeds a critical point αc1. Although there is another critical point αc2 in a finite system at which the ground state evolves from the canted state to the collinear Neel plus ferromagnetic state, that state is absent because αc2 tends to infinity in the thermodynamic limit. Thus, the quantum ground state phase diagram of the chain is composed of the collinear quasi-Neel state and canted state. The precise critical line between those two states is determined by the numerical ED method when -1 ≤ β ≤ -0.1. Except the small β parameter region, the CCM can also be used to obtain the accurate critical line. The type of the phase transition occurring at αc1 is also analyzed by using ED and CCM. © 2015 The Physical Society of Japan.


Jiang J.-J.,Sanjiang College | Liu Y.-J.,Yangzhou University | Tang F.,Yangzhou Polytechnic Institute | Yang C.-H.,Nanjing University of Information Science and Technology | Sheng Y.-B.,Nanjing University
Communications in Theoretical Physics | Year: 2014

By using the coupled cluster method and the numerical density matrix renormalization group method, we investigate the properties of the quantum plateau state in an alternating Heisenberg spin chain. In the absence of a magnetic field, the results obtained from the coupled cluster method and density matrix renormalization group method both show that the ground state of the alternating chain is a gapped dimerized state when the parameter α exceeds a critical point αc. The value of the critical points can be determined precisely by a detailed investigation of the behavior of the spin gap. The system therefore possesses an m = 0 plateau state in the presence of a magnetic field when α > αc. In addition to the m = 0 plateau state, the results of density matrix renormalization group indicate that there is an m = 1/4 plateau state that occurs between two critical fields in the alternating chain if α > 1. The mechanism for the m = 1/4 plateau state and the critical behavior of the magnetization as one approaches this plateau state are also discussed. © 2013 Chinese Physical Society and IOP Publishing Ltd.


Jiang J.-J.,Sanjiang College | Liu Y.-J.,Yangzhou University | Tang F.,Yangzhou Polytechnic Institute | Yang C.-H.,Nanjing University of Information Science and Technology
Physica B: Condensed Matter | Year: 2012

By using the method of exact diagonalization, we investigated the properties of the distorted mixed spin (1, 1/2) diamond chain with antiferromagnetic interactions along the rung and leg. The ground states of this model contain the sawtooth chain state and the rung dimer plus Haldane state. The research on the origin of the spin gap of the model discloses that there are three different types of spin excitations at different parameter regimes due to the competition among the interactions J 1, J 2 and J 3. © 2012 Elsevier B.V. All rights reserved.


Jiang J.-J.,Sanjiang College | Yang C.-H.,Nanjing University of Information Science and Technology | Liu Y.-J.,Yangzhou University
Wuli Xuebao/Acta Physica Sinica | Year: 2012

By using the method of exact diagonalization, the properties of the spin-1/2 ferromagnetic-antiferromagnetic alternating Heisenberg chain are investigated. The spin-spin correlation, the sublattice magnetizations, the spin excitation spectrum and the magnetization curve of the model are calculated and compared with the corresponding properties of the mixed spin chain. The results show that the behaviors of the alternating Heisenberg chain are equivalent to those of the mixed spin chain when the ratio of antiferromagnetic to ferromagnetic coupling strength α is very small. So, the properties of the mixed spin chain can be analyzed by using the spin-1/2 ferromagnetic-antiferromagnetic-antiferromagnetic alternating Heisenberg chain. © 2012 Chinese Physical Society.


Qu L.,SanJiang College | He D.,Nanjing Southeast University
Advanced Materials Research | Year: 2012

This article describes the vehicle based on virtual instrument engine control system research and development of the experimental platform. Virtual instrument technology combined with artificial intelligence inference mechanism for the establishment of a virtual instrument based on the engine electronic control system testing and fault diagnosis system, to achieve the electronic control engine system sensors online test, waveform analysis, data storage, replay and failure diagnosis. © (2012) Trans Tech Publications, Switzerland.

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