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921.
Akihiro Tohsaki 《Frontiers of Physics》2011,6(3):320-336
We explain how to treat a microscopic wave function of ??-condensation taking a 3??-nucleus as a typical example. The wave function has been originally proposed ten years before by Horiuchi, R?pke, Schuck and the present author (Phys. Rev. Lett., 2001, 87: 192501). The microscopic model, which fully takes into account the Pauli principle between all the constituent nucleons, effective internucleon forces and the Coulomb force, can play an important role in reproducing an ??-gas nature thanks to ??-condensation as an excited state of ??-like nuclei. An essential point of the wave function is to describe their ground state simultaneously. We study its typical features by giving an analytical formula of the norm kernel and the kernel concerning the one-body operator for 3??-condensation. 相似文献
922.
We study critical behaviors of the reduced fidelity susceptibility for two neighboring sites in the onedimensional transverse field Ising model. It is found that the divergent behaviors of the susceptibility take the form of square of logarithm, in contrast with the global ground-state fidelity susceptibility which is power divergence. In order to perform a scaling analysis, we take the square root of the susceptibility and determine the scaling exponent analytically and the result is further confirmed by numerical calculations. 相似文献
923.
The effects of spin-spin interaction on thermed entanglement of a two-qubit Heisenberg XYZ model with different inhomogeneous magnetic fields are investigated. It is shown that the entanglement is dependent on the spin-spin interaction and the inhomogeneous magnetic fields. The larger the Ji (i-axis spin-spin interaction), the higher critical value the Bi (i-axis uniform magnetic field) has. Moreover, in the weak-field regime, the larger Ji corresponds to more entanglement, while in the strong-field regime, different Ji correspond to the same entanglement. In addition, it is found that with the increase of Ji, the concurrence can approach the maximum value more rapidly for the smaller Bi, and can reach a larger value for the smaller bi (i-axis nonuniform magnetic field). So we can get more entanglement by increasing the spin-spin interaction Ji, or by decreasing the uniform magnetic field Bi and the nonuniform magnetic field hi. 相似文献
924.
The Casimir effect of a piston for massless scalar fields which satisfy Dirichlet boundary conditions in the context of five-dimensional Randall- Sundrum models is studied. In these scenarios we derive and calculate the expression for the Casimir force on the piston. We also discuss the Casimir force in the limit that one outer plate is moved to the remote place to show that the nature of the reduced force between the parallel plates left. In the Randall~undrum model involving two branes the two plates attract each other when they locate very closely, but the reduced Casimir force turns to be repulsive as the plates separation is not extremely tiny, which is against the experimental phenomena, meaning that the RSI model can not be acceptable. In the case of one brane model the shape of the reduced Casimir force is similar to that of the standard two-parallel-system in the four-dimensional fiat spacetimes while the sign of force remains negative. 相似文献
925.
Baxter P. Rogers Santosh B. Katwal Victoria L. Morgan Christopher L. Asplund John C. Gore 《Magnetic resonance imaging》2010
Connectivity refers to the relationships that exist between different regions of the brain. In the context of functional magnetic resonance imaging (fMRI), it implies a quantifiable relationship between hemodynamic signals from different regions. One aspect of this relationship is the existence of small timing differences in the signals in different regions. Delays of 100 ms or less may be measured with fMRI, and these may reflect important aspects of the manner in which brain circuits respond as well as the overall functional organization of the brain. The multivariate autoregressive time series model has features to recommend it for measuring these delays and is straightforward to apply to hemodynamic data. In this review, we describe the current usage of the multivariate autoregressive model for fMRI, discuss the issues that arise when it is applied to hemodynamic time series and consider several extensions. Connectivity measures like Granger causality that are based on the autoregressive model do not always reflect true neuronal connectivity; however, we conclude that careful experimental design could make this methodology quite useful in extending the information obtainable using fMRI. 相似文献
926.
Jin-Luen Lee Rainer Bleck Alexander E. MacDonald 《Journal of computational physics》2010,229(24):9284-9298
A multistep flux-corrected transport (MFCT) scheme is developed to achieve conservative and monotonic tracer transports for multistep dynamical cores. MFCT extends Zalesak two-time level scheme to any multistep time-differencing schemes by including multiple high-order fluxes in the antidiffusive flux, while computing the two-time level low-order monotone solution. The multistep time-differencing scheme used in this study is the third-order Adams–Bashforth (AB3) scheme implemented in a finite-volume icosahedral shallow-water model. The accuracy of AB3 MFCT is quantified by the shape-preserving advection experiments in non-divergent flow, as well as a cosine bell whose shape changes during advection in shear flow. AB3 MFCT has been shown to be insensitive to time step size. This make AB3 MFCT an attractive transport scheme for explicit high resolution model applications with small time step. MFCT is tested in shallow-water model simulations to demonstrate that the use of MFCT maintains positive-definite tracer transport, while at the same time conserving both fluid mass and tracer mass within round-off errors in the AB3 dynamic core. 相似文献
927.
We investigated a far-field superlens operating at mid-infrared wavelength that allows resolving subwavelength features in the far-field. By utilizing evanescent enhancement provided by surface plasmon excitation of silver nanorods and Moiré effect, we numerically demonstrated that subwavelength information of an object can be converted to propagating information. This information can then be captured by conventional optical components. A simple image reconstruction algorithm can restore the subwavelength object. A sub-diffraction-limited resolution of 2.5 μm at 6-μm wavelength is demonstrated. 相似文献
928.
The thermal quantum discord (QD) is studied in a two-qubit Heisenberg XXZ system with Dzyaloshinskii-Moriya (DM) interaction. We compare the thermal QD with thermal entanglement in this system and find remarkable differences between them. For instance, we show situations where QD decreases asymptotically to zero with temperature T while entanglement decreases to zero at the point of critical temperature, situations where QD decreases with certain tunable parameters such as Dz and Dx when entanglement increases. We find that the characteristic of QD is exotic in this system and this possibly offers a potential solution to enhance entanglement of a system. We also show that tunable parameter Dx is more efficient than parameter Dz in most regions for controlling the QD. 相似文献
929.
There are some uncertain characteristics of the Ds1(2536), which deserves further discussion. Based on the assumption that the meson is constituted by c\bar{s}, and belongs to T doublet (1+,2+), radiative decays Ds1(2536)→Ds(1968)+γ and Ds1(2536)→ Ds*(2112)+γ are studied in the CQM model. The large branching ratios of them from our calculations not only indicate the process may be detected in the future experiments, but also can give a deep comprehension of the structure of it. 相似文献
930.
F1-ATPase, a part of ATP synthase, can synthesize and hydrolyze ATP moleculars in which the central γ-subunit rotates inside the α3β3 cylinder. Astochastic four-state mechanochemical coupling model of F$_{1}$-ATPase isstudied with the aid of the master equation. In this model, the ATPhydrolysis and synthesis are dependent on ATP, ADP, and Pi concentrations.The effects of ATP concentration, ADP concentration, and the external torqueon the occupation probability of binding-state, the rotation rate and thediffusion coefficient of F1-ATPase are investigated. Moreover, theresults from this model are compared with experiments. The mechanochemicalmechanism F1-ATPase is qualitatively explained by the model. 相似文献