118606470
Constraints on a phiCDM model from strong gravitational lensing and updated Hubble parameter measurements
We constrain the scalar field dark energy model with an inverse power-law potential, i.e., V()  −α (α > 0), from a set of recent cosmological observations by compiling an updated sample of Hubble parameter measurements including 30 independent data points. Our results show that the constraining power of the updated sample of H(z) data with the HST prior on H0 is stronger than those of the SCP Union2 and Union2.1 compilations. A recent sample of strong gravitational lensing systems is also adopted to confine the model even though the results are not significant. A joint analysis of the strong gravitational lensing data with the more restrictive updated Hubble parameter measurements and the Type Ia supernovae data from SCP Union2 indicates that the recent observations still can not distinguish whether dark energy is a time-independent cosmological constant or a time-varying dynamical component.
119109342
Constraints on the exponential $f(R)$ model from latest Hubble parameter measurements
We investigate the viable exponential $f(R)$ gravity in the metric formalism with $f(R)=-\beta R_s (1-e^{-R/R_s})$. The latest sample of the Hubble parameter measurements with 23 data points is used to place bounds on this $f(R)$ model. A joint analysis is also performed with the luminosity distances of Type Ia supernovae and baryon acoustic oscillations in the clustering of galaxies, and the shift parameters from the cosmic microwave background measurements, which leads to $0.240 1.47$ at 1$\sigma$ confidence level. The evolutions of the deceleration parameter $q(z)$ and the effective equations of state $\omega_{de}^{eff}(z)$ and $\omega_{tot}^{eff}(z)$ are displayed. By taking the best-fit parameters as prior values, we work out the transition redshift (deceleration/acceleration) $z_T$ to be about 0.77. It turns out that the recent observations are still unable to distinguish the background dynamics in the $\Lambda$CDM and exponential $f(R)$ models.
119352619
Decomposition of SU(N) connection and effective theory of SU(N) QCD
We give a general decomposition of SU(N) connection and derive a generalized Skyrme-Faddeev action as the effective action of SU(N) QCD in the Low energy limit. The result is obtained by separating the topological degrees which describes the non-Abelian monopoles from the dynamical degree of gauge potential, and integrating all the dynamical degrees of SU(N) QCD. (C) 2000 Published by Elsevier Science B.V.
121278747
On Dirac's quantization condition
The consequences of Dirac's quantization condition are discussed. Observing that this condition generally leads to contradiction and that the normal explanation to resolve the contradiction seems unsatisfactory, we propose a modified quantization condition. It is shown that operator ordering ambiguity could be represented as the arbitrariness of the distribution functions in the modified condition.
122931816
Gauge field theory for fermions
Inhomogeneous nonlinear gauge field theory for fermions is studied in detail. We show that the Lagrangian of the standard model can be rewritten in terms of the nonlinear connection.
15588368
Geometric Quantization of free fields in space of motions
Via K$\ddot{a}$hker polarization we geometrically quantize free fields in the spaces of motions, namely the space of solutions of equations of motion. We obtain the correct results just as that given by the canonical quantization. Since we follow the method of covariant symplectic current proposed by Crnkovic, Witten and Zuckerman et al, the canonical commutator we obtained are naturally invariant under proper Lorentz transformation and the discrete parity and time transverse transformations, as well as the equations of motion.
121118981
Numerical study on quench process and protection of BES III superconducting detector magnet
A 3D quench simulation model was developed for the BES III magnet, which is a superconducting solenoid used in Beijing Spectrometer III (BES III) of Beijing Electron and Positron Collider II (BEPC II). The BES III magnet was inner winded with aluminum stabilized Rutherford cable and conduction-cooled with forced flow of two phase helium. Quench processes of the magnet under different protection techniques were simulated with the model. The minimum quench energy, the quench propagation velocity, the maximum temperature rise and the maximum voltage drop of the coil were analyzed. Protection capabilities of the different techniques were compared according to the simulation results, and the simulation results were compared with the experimental data. Recommendations to the protection of the detector magnets are presented.