Block-block entanglement and quantum phase transitions in one-dimensional extended Hubbard model

In this paper, we study block-block entanglement in the ground state of one-dimensional extended Hubbard model. Our results show that the phase diagram derived from the block-block entanglement manifests richer structure than that of the local (single site) entanglement because it comprises nonlocal correlation. Besides phases characterized by the charge-density-wave, the spin-density-wave, and phase-separation, which can be sketched out by the local entanglement, singlet superconductivity phase could be identified on the contour map of the block-block entanglement. Scaling analysis shows that ${\rm log}_2(l)$ behavior of the block-block entanglement may exist in both non-critical and the critical regions, while some local extremum are induced by the finite-size effect. We also study the block-block entanglement defined in the momentum space and discuss its relation to the phase transition from singlet superconducting state to the charge-density-wave state.Comment: 8 pages, 9 figure

Entanglement and quantum phase transition in the extended Hubbard model

We study quantum entanglement in one-dimensional correlated fermionic system. Our results show, for the first time, that entanglement can be used to identify quantum phase transitions in fermionic systems.Comment: 5 pages, 4 figure

Effect of process parameters on forming quality of Mg alloy(MZ21)-Al alloy(7075) composite pipe

This paper mainly studies the effect of process parameters on the deformation mechanism of MZ21 magnesium alloy and 7075 aluminum alloy bimetal composite pipe in spinning process.The two parameters of spinning, the rotary wheel feed ratio and the double tube wall thinning rate were selected to study, and the influence rule of each process parameter on the forming quality of composite tube was simulated by Simufact software. Under different thinning rates of the total wall thickness, the coordinated deformation and the rebound law of the wall thickness of the composite pipe are obtained. The results provide a certain reference for the preparation of magnesium aluminum composite pipe and the selection of reasonable spinning parameters

Global axisymmetric stability analysis for a composite system of two gravitationally coupled scale-free discs

In a composite system of gravitationally coupled stellar and gaseous discs, we perform linear stability analysis for axisymmetric coplanar perturbations using the two-fluid formalism. The background stellar and gaseous discs are taken to be scale-free with all physical variables varying as powers of cylindrical radius $r$ with compatible exponents. The unstable modes set in as neutral modes or stationary perturbation configurations with angular frequency $\omega=0$.Comment: 7 pages using AAS styl

Numerical analysis of integrated forming process of diagonal rolling and piercing of flange nuts

In this paper, Simufact FE software is used to establish a simulation model of three-roll diagonal roll piercing integrated forming flange nut blanks, elaborate its process principle, analyze its forming process through numerical simulation. The law of load change, equivalent plastic strain distribution and wall thickness uniformity during the piercing process and diameter reduction process were investigated, and verify the feasibility of this forming process for manufacturing flange nut blanks

Numerical analysis of integrated forming process of diagonal rolling and piercing of flange nuts

In this paper, Simufact FE software is used to establish a simulation model of three-roll diagonal roll piercing integrated forming flange nut blanks, elaborate its process principle, analyze its forming process through numerical simulation. The law of load change, equivalent plastic strain distribution and wall thickness uniformity during the piercing process and diameter reduction process were investigated, and verify the feasibility of this forming process for manufacturing flange nut blanks

Movement analysis of lower limb during backward walking with unstable intervention

Backward walking (BW), an emerging rehabilitative and training modality, was integrated with unstable sole construction with various hardness levels to analyze the kinematic and kinetic characteristics of the lower extremities. Eighteen participants volunteered to participate in the test. They performed walking tests under three conditions: 1) BW with normal shoes (NBW); 2) BW with unstable shoes with soft unstable elements (UBW-S); 3) BW with unstable shoes with hard unstable elements (UBW-H). The results show increased hip and ankle flexion and increased knee flexion-extension extent in the stance phase during BW with unstable shoes. The motor control mechanism of unstable BW enhanced the rehabilitation of lower limb deficiency. The attached unstable elements (UBW-S and UBW-H) induced local perturbation to stimulate proprioceptive ability and the neuromuscular system, changing the plantar loading distribution in a certain region. Future study should concentrate on the possible rehabilitative effect of unstable BW on neurological disorders and motor system deficiency