Entanglement and quantum phase transition in the one-dimensional anisotropic XY model

In this paper the entanglement and quantum phase transition of the anisotropic s=1/2 XY model are studied by using the quantum renormalization group method. By solving the renormalization equations, we get the trivial fixed point and the untrivial fixed point which correspond to the phase of the system and the critical point, respectively. Then the concurrence between two blocks are calculated and it is found that when the number of the iterations of the renormalziation trends infinity, the concurrence develops two staturated values which are associated with two different phases, i.e., Ising-like and spin-fluid phases. We also investigate the first derivative of the concurrence, and find that there exists non-analytic behaviors at the quantum critical point, which directly associate with the divergence of the correlation length. Further insight, the scaling behaviors of the system are analyzed, it is shown that how the maximum value of the first derivative of the concurrence reaches the infinity and how the critical point is touched as the size of the system becomes large.Comment: 10 pages, 5 figure

Tuning Magnetic Avalanches in Mn12-ac

Using micron-sized Hall sensor arrays to obtain time-resolved measurements of the local magnetization, we report a systematic study in the molecular magnet Mn$_{12}$-acetate of magnetic avalanches controllably triggered in different fixed external magnetic fields and for different values of the initial magnetization. The speeds of propagation of the spin-reversal fronts are in good overall agreement with the theory of magnetic deflagration of Garanin and Chudnovsky \cite{Garanin}.Comment: 8 pages, 7 figures; discussion expanded and revise

Scale-free download network for publications

The scale-free power-law behavior of the statistics of the download frequency of publications has been, for the first time, reported. The data of the download frequency of publications are taken from a well-constructed web page in the field of economic physics (http://www.unifr.ch/econophysics/). The Zipf-law analysis and the Tsallis entropy method were used to fit the download frequency. It was found that the power-law exponent of rank-ordered frequency distribution is $\gamma \sim 0.38 \pm 0.04$ which is consistent with the power-law exponent $\alpha \sim 3.37 \pm 0.45$ for the cumulated frequency distributions. Preferential attachment model of Barabasi and Albert network has been used to explain the download network.Comment: 3 pages, 2 figure

Δ\Delta-scaling and Information Entropy in Ultra-Relativistic Nucleus-Nucleus Collisions

The $\Delta$-scaling method has been applied to ultra-relativistic p+p, C+C and Pb+Pb collision data simulated using a high energy Monte Carlo package, LUCIAE 3.0. The $\Delta$-scaling is found to be valid for some physical variables, such as charged particle multiplicity, strange particle multiplicity and number of binary nucleon-nucleon collisions from these simulated nucleus-nucleus collisions over an extended energy ranging from $E_{lab}$ = 20 to 200 A GeV. In addition we derived information entropy from the multiplicity distribution as a function of beam energy for these collisions.Comment: 4 pages, 4 figures, 1 table; to appear in the July Issue of Chin. Phys. Lett.. Web Page: http://www.iop.org/EJ/journal/CP

The influence of parent austenite characteristics on the intervariant boundary network in a lath martensitic steel

The influence of the parent austenite deformation state on the intervariant boundary network (i.e., population, plane orientation, and connectivity) of a lath martensitic microstructure was investigated using conventional EBSD mapping and five-parameter boundary analysis approach along with quantification of boundary connectivity using homology metrics. The lath martensite largely revealed a bimodal misorientation angle distribution, closely matched with the Kurdjumov–Sachs (K–S) orientation relationship. The application of deformation significantly changed the distribution, gradually reducing the intensity of the 60° misorientation angle peak. This was largely ascribed to substructure development within the parent austenite upon deformation, which stimulates particular variant/s having a habit plane (011)α′ closely parallel to the primary (111)γ and/or secondary (11¯¯¯1)γ slip plane. The interaction of these variants eventually promoted specific intervariant boundaries (e.g., 60°/[111], 10.5°/[011], and 49.5°/[110]) at the expense of 60°/[011]. The application of deformation in the parent austenite did not change the intervariant boundary plane character distribution, which mostly exhibited an anisotropic character terminated on {110} planes because of the displacive nature of the martensitic transformation. However, the extent of anisotropy progressively decreased with increasing strain in the austenite prior to transformation. The grain boundary network connectivity was markedly altered due to the local variant selection induced by the deformation. Deformation in the austenite regime generally decreased the connectivity of boundaries having a {110} plane orientation. The intervariant boundaries with the {110} twist character also displayed a similar trend, though the connectivity of {110} tilt boundaries progressively enhanced with increasing strain. The former was closely matched with a decrease in the population of 60°/[110] intervariant boundaries with the strain. The current findings suggest that the intervariant boundary network of lath martensite can be manipulated through changes in the parent austenite deformation state which, in turn, can be used to enhance key final product properties such as toughness.publishedVersio

Total Reaction Cross Section in an Isospin-Dependent Quantum Molecular Dynamics (IDQMD) Model

The isospin-dependent quantum molecular dynamics (IDQMD) model is used to study the total reaction cross section $\sigma_R$. The energy-dependent Pauli volumes of neutrons and protons have been discussed and introduced into the IDQMD calculation to replace the widely used energy-independent Pauli volumes. The modified IDQMD calculation can reproduce the experimental $\sigma_R$ well for both stable and exotic nuclei induced reactions. Comparisons of the calculated $\sigma_R$ induced by $^{11}Li$ with different initial density distributions have been performed. It is shown that the calculation by using the experimentally deduced density distribution with a long tail can fit the experimental excitation function better than that by using the Skyrme-Hartree-Fock calculated density without long tails. It is also found that $\sigma_R$ at high energy is sensitive to the long tail of density distribution.Comment: 4 page, 4 fig