Chinese Physics B

Bao, Jianghong; Chen, Dandan

doi: 10.1088/1674-1056/26/8/080201pmid: N/A

This paper introduces a four-dimensional (4D) segmented disc dynamo which possesses coexisting hidden attractors with one stable equilibrium or a line equilibrium when parameters vary. In addition, by choosing an appropriate bifurcation parameter, the paper proves that Hopf bifurcation and pitchfork bifurcation occur in the system. The ultimate bound is also estimated. Some numerical investigations are also exploited to demonstrate and visualize the corresponding theoretical results.

Gorgulu, Melis Zorsahin; Dag, Idris; Irk, Dursun

doi: 10.1088/1674-1056/26/8/080202pmid: N/A

In this paper, an approximate function for the Galerkin method is composed using the combination of the exponential B-spline functions. Regularized long wave equation (RLW) is integrated fully by using an exponential B-spline Galerkin method in space together with Crank–Nicolson method in time. Three numerical examples related to propagation of single solitary wave, interaction of two solitary waves and wave generation are employed to illustrate the accuracy and the efficiency of the method. Obtained results are compared with some early studies.

Wu, Yi; Ma, Yong-Qi; Feng, Wei; Cheng, Yu-Min

doi: 10.1088/1674-1056/26/8/080203pmid: N/A

The improved element-free Galerkin (IEFG) method of elasticity is used to solve the topology optimization problems. In this method, the improved moving least-squares approximation is used to form the shape function. In a topology optimization process, the entire structure volume is considered as the constraint. From the solid isotropic microstructures with penalization, we select relative node density as a design variable. Then we choose the minimization of compliance to be an objective function, and compute its sensitivity with the adjoint method. The IEFG method in this paper can overcome the disadvantages of the singular matrices that sometimes appear in conventional element-free Galerkin (EFG) method. The central processing unit (CPU) time of each example is given to show that the IEFG method is more efficient than the EFG method under the same precision, and the advantage that the IEFG method does not form singular matrices is also shown.

Zhao, Zi-Long; Long, Chao-Yun; Long, Zheng-Wen; Xu, Ting

doi: 10.1088/1674-1056/26/8/080301pmid: N/A

In the present work, the generalized Kemmer oscillator was introduced in one dimension. It is shown that the exact solutions of generalized Kemmer oscillator with some appropriate choices of the interactions f(x) have been obtained by using the Nikiforov–Uvarov (NU) method. Moreover, several interesting cases are discussed.

Yang, Lian-Wu; Xia, Yun-Jie

doi: 10.1088/1674-1056/26/8/080302pmid: N/A

The present studies show that any nonzero amount of coherence of a system can be converted into entanglement between the system and an incoherent ancillary system via incoherent operations. According to this conclusion, we study the process of converting coherence into entanglement via a unitary operation where the initial ancillary system is of different quantum state. We find that some other conditions should be satisfied in converting coherence into entanglement. We also study the conditions of coherence consumption of converting coherence into entanglement.

Wu, Wen-Bo; Wu, Chun-Wang; Li, Jian; Ou, Bao-Quan; Xie, Yi; Wu, Wei; Chen, Ping-Xing

doi: 10.1088/1674-1056/26/8/080303pmid: N/A

Calculating the spatial structures of ion crystals is important in ion-trapped quantum computation. Here we demonstrate that the simulated annealing method is a powerful tool to evaluate the structures of ion crystals. By calculating equilibrium positions of 10 ions under harmonic potential and those of 120 ions under anharmonic potential, both with the standard procedure and simulated annealing method, we find that the standard procedure to evaluate spatial structures is complicated and may be inefficient in some cases, and that the simulated annealing method is more favorable.

Zhang, Huafeng; Chen, Fang; Yu, Chunchao; Sun, Lihui; Xu, Dahai

doi: 10.1088/1674-1056/26/8/080304pmid: N/A

Properties of the ground-state solitons, which exist in the spin–orbit coupling (SOC) Bose–Einstein condensates (BEC) in the presence of optical lattices, are presented. Results show that several system parameters, such as SOC strength, lattice depth, and lattice frequency, have important influences on properties of ground state solitons in SOC BEC. By controlling these parameters, structure and spin polarization of the ground-state solitons can be effectively tuned, so manipulation of atoms may be realized.

Xu, Jia-Hao; Shao, Cheng-Gang; Luo, Jie; Liu, Qi; Zhu, Lin; Zhao, Hui-Hui

doi: 10.1088/1674-1056/26/8/080401pmid: N/A

A high accuracy test of the weak equivalence principle (WEP) is of great scientific significance no matter whether its result is positive. We analyze the gravity gradient effect which is a main systematic error source in the test of WEP. The result shows that the uncompensated gravity gradient effect from the coupling term of the dominated gravity gradient multipole moment component q21 and the relative multipole field component Q21 contributes to an uncertainty of 1 × 10−11 on the Eötvös parameter. We make a Q21 compensation to reduce the effect by about 20 times, and the limit of the test precision due to this coupling is improved to a level of a part in 1013.

She, Zhen-Su

doi: 10.1088/1674-1056/26/8/080501pmid: N/A

The resolution by Chen and Sun of divergent Chapman–Enskog expansion problem will not only build a unified foundation for non-equilibrium dynamics modeling at all Mach number and Knudsen number, but also shed light to a large class of difficult theoretical problems involving divergent expansion on strong nonlinearity.

Li, Hai-bin; Yang, Yang; Wang, Pei; Wang, Xiao-guang

doi: 10.1088/1674-1056/26/8/080502pmid: N/A

We propose a quantity called modulus fidelity to measure the closeness of two quantum pure states. We use it to investigate the closeness of eigenstates in one-dimensional hard-core bosons. When the system is integrable, eigenstates close to their neighbor or not, which leads to a large fluctuation in the distribution of modulus fidelity. When the system becomes chaos, the fluctuation is reduced dramatically, which indicates all eigenstates become close to each other. It is also found that two kind of closeness, i.e., closeness of eigenstates and closeness of eigenvalues, are not correlated at integrability but correlated at chaos. We also propose that the closeness of eigenstates is the underlying mechanism of eigenstate thermalization hypothesis (ETH) which explains the thermalization in quantum many-body systems.