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1.
In this paper we classify cylindrically symmetric static space-timesaccording to their teleparallel homothetic vector fields using directintegration technique. It turns out that the dimensions of the teleparallelhomothetic vector fields are 4, 5, 7 or 11, which are the same in numbers asin general relativity. In case of 4, 5 or 7 proper teleparallel homotheticvector fields exist for the special choice to the space-times. In the caseof 11 teleparallel homothetic vector fields the space-time becomes Minkowskiwith all the zero torsion components. Teleparallel homothetic vector fieldsin this case are exactly the same as in general relativity. It is importantto note that this classification also covers the plane symmetric static space-times.  相似文献   

2.
In this paper we classify Bianchi type Ⅷ and Ⅸ space-times according to their teleparallel Killing vector fields in the teleparallel theory of gravitation by using a direct integration technique.It turns out that the dimensions of the teleparallel Killing vector fields are either 4 or 5.From the above study we have shown that the Killing vector fields for Bianchi type VIII and IX space-times in the context of teleparallel theory are different from that in general relativity.  相似文献   

3.
In this paper we classify Kantowski-Sachs and Bianchi type Ⅲ space-times according to their teleparallel Killing vector fields using direct integration technique. It turns out that the dimension of the telepaxallel Killing vector fields are 4 or 6, which are the same in numbers as in general relativity. In case of 4 the teleparallel Killing vector fields are multiple of the corresponding Killing vector fields in general relativity by some function of t. In the case of 6 Killing vector fields the metric functions become constants and the Killing vector fields in this case are exactly the same as in general relativity. Here we also discuss the Lie algebra in each case.  相似文献   

4.
5.
We have studied the conformal, homothetic and Killing vectors in the context of teleparallel theory of gravitation for plane-symmetric static spacetimes. We have solved completely the non-linear coupled teleparallel conformal Killing equations. This yields the general form of teleparallel conformal vectors along with the conformal factor for all possible cases of metric functions. We have found four solutions which are divided into one Killing symmetries and three conformal Killing symmetries. One of these teleparalel conformal vectors depends on x only and other is a function of all spacetime coordinates. The three conformal Killing symmetries contain three proper homothetic symmetries where the conformal factor is an arbitrary non-zero constant.  相似文献   

6.
H. Schmieden 《中国物理 C》2009,33(12):1146-1152
Measurements of ω photoproduction of the Crystal-Barrel/TAPS experiment at the ELSA accelerator of Bonn University are presented which used linearly polarized tagged photon beam from threshold to Eγ = 1700MeV. The azimuthal asymmetries ∑and ∑πindicate s-channel resonance contributions on top of the established t-channel exchange processes. These findings are further enhanced by a very first measurement of the G-asymmetry which, in addition to the polarized photon beam, also requires a longitudinally polarized proton target. An intuitive interpretation of the specific sensitivity of the azimuthal asymmetries to the reaction mechanisms involved is given.  相似文献   

7.
The Dirac equations with vector and scalar potentials of the Coulomb types in two and three dimensions are solved using the supersymmetric quantum mechanics method. For the system of such potentials, the analytical expressions of the matrix dements for both position and momentum operators are obtained.  相似文献   

8.
Based on the generalized vector meson dominance model in QCD, we study photoproduction of vector meson T off the proton by use of the QCD inspired model in which the contributions from quark-quark, gluon-gluon, and quark-gluon interference term to observable are taken into consideration. Calculations are performed for total cross section σtot, differential cross section dσ/dt, ratio of the real part to imaginary part of forward scattering amplitude ρ, and nuclear slop parameter function β. The mediators of interactions between projectiles (the quark and antiquark pair fluctuated from the real the photon) and the proton target (three-quark system) are the tensor Glueball and Odderon instead of using the usual Pomeron exchange. The theoretical predictions for σtot (s) are consistent with the experimental data within error bars of the data. The data for dσ/dt, ρ, and β are urgently needed.  相似文献   

9.
Based on the quark-gluon contents of nucleon and strongly believing that the force mediators, Pomeron and its counterpart in the conventional approach of Regge theory, for high energy diffractive process would be the tensor glueball and Odderon respectively, we discuss photo-production of vector meson Ф off the deuteron at energy less than 3 GeV in the QCD inspired model in which the quark gluon degrees of freedom and glueball, Odderon exchange are taken into account. A calculation is performed for γ + D →Ф + D, and the theoretical predictions of the differential cross section dσ^γD/dt, are presented and compared with available experimental data. Our QCD inspired model reproduces data quite well in the whole range of the experimental measurements up to |t| ≌ 0.4 GeV. Our results can be used to extract γn → Фn data, which cannot be measured in experiment.  相似文献   

10.
The vector correlations between products and reagents for the reactions Ne+H2+, Ne+D2+, and Ne+T2+ are calculated by means of the quasi-classical trajectory method on a new potential energy surface constructed by Lfi et al, [J. Chem. Phys. 2010 132, 014303]. The polarization-dependent differential cross-sections (27π/σ)(dσ00/dωt), (2π/σ)(dσ20/dwt), (27π/σ)(dσ22+/dwt), and (2π/σ)(dσ21-/dwt), and the distributions of P(θr), P(φ), and P(θr, Cr) are calculated. The isotopic effect, which is associated with the difference in mass factor among the three reactions, is revealed.  相似文献   

11.
Quasiclassical trajectory (QCT) calculations are first carried out to study the stereodynamics of the S (3p) + H2 → SH + H reaction based on the ab initio 13Atr potential energy surface (PES) (Lii etal. 2012 J. Chem. Phys. 136 094308). The QCT-calculated reaction probabilities and cross sections for the S + H2 (v = 0, j = 0) reaction are in good agreement with the previous quantum mechanics (QM) results. The vector properties including the alignment, orientation, and polarization- dependent differential cross sections (PDDCSs) of the product SH are presented at a collision energy of 1.8 eV. The effects of the vibrational and rotational excitations of reagent on the stereodynamics are also investigated and discussed in the present work. The calculated QCT results indicate that the vibrational and rotational excitations of reagent play an important role in determining the stereodynamic properties of the title reaction.  相似文献   

12.
Quasi-classical trajectory (QCT) calculations have been performed to study the product polarization behaviours in the reaction O(3P) + D2 (v = 0, j = 0) → OD + D. By running trajectories on the 3A and 3A potential energy surfaces (PESs), vector correlations such as the distributions of the polarization-dependent differential cross sections (PDDCSs), the angular distributions of P (θr) and P (φr) are presented. Isotope effect is discussed in this work by a comprehensive comparison with the reaction O(3P) + H2 (v = 0, j = 0) → H + H. Common characteristics as well as differences are discussed in product alignment and orientation for the two reactions. The isotope mass effect differs on the two potential energy surfaces: the isotope mass effect has stronger influence on P (θr) and PDDCSs of the 3A PES while the opposite on P (φr) of the 3A potential energy surface.  相似文献   

13.
A cardiac vector model is presented and verified, and then the forward problem for cardiac magnetic fields and electric potential are discussed based on this model and the realistic human torso volume conductor model, including lungs. A torso-cardiac vector model is used for a 12-lead electrocardiographic (ECG) and magneto-cardiogram (MCG) simulation study by using the boundary element method (BEM). Also, we obtain the MCG wave picture using a compound four-channel HTc ·SQUID system in a magnetically shielded room. By comparing the simulated results and experimental results, we verify the cardiac vector model and then do a preliminary study of the forward problem of MCG and ECG. Therefore, the results show that the vector model is reasonable in cardiac electrophysiology.  相似文献   

14.
Quasi-classical trajectory theory is used to study the reaction of O(3p) with H2 (D2) based on the ground 3A″ potential energy surface (PES). The reaction cross section of the reaction O+H2→+OH+H is in excellent agreement with the previous result. Vector correlations, product rotational alignment parameters (P2(j′. k)) and several polarizeddependent differential cross sections are further calculated for the reaction. The product polarization distribution exhibits different characteristics that can be ascribed to different motion paths on the PES, arising from various collision energies or mass factors.  相似文献   

15.
The energy preserving average vector field (AVF) method is applied to the coupled Schr6dinger-KdV equations. Two energy preserving schemes are constructed by using Fourier pseudospectral method in space direction discretization. In order to accelerate our simulation, the split-step technique is used. The numerical experiments show that the non-splitting scheme and splitting scheme are both effective, and have excellent long time numerical behavior. The comparisons show that the splitting scheme is faster than the non-splitting scheme, but it is not as good as the non-splitting scheme in preserving the invariants.  相似文献   

16.
We investigate the decomposition of noncommutative gauge potential Ai, and find that it has inner structure, namely, Ai can be decomposed in two parts, bi and αi, where bi satisfies gauge transformations while αi satisfies adjoint transformations, so dose the Seiberg-Witten mapping of noncommutative U(1) gauge potential. By means of Seiberg-Witten mapping, we construct a mapping of unit vector field between noncommutative space and ordinary space, and find the noncommutative U(1) gauge potential and its gauge field tensor can be expressed in terms of the unit vector field. When the unit vector field has no singularity point, noncommutative gauge potential and gauge field tensor will equal ordinary gauge potential and gauge field tensor  相似文献   

17.
H.-Ch. Kim  T. Ledwig  S.i. Nam 《中国物理 C》2009,33(12):1279-1284
We present recent investigations on the vector and axial-vector transitions of the baryon antidecuplet within the framework of the self-consistent SU(3) chiral quark-soliton model, taking into account the 1/No rotational and linear mscorrections. The main contribution to the electric-like transition form factor comes from the wave-function corrections. This is a consequence of the generalized Ademollo-Gatto theorem. It is also found that in general the leading-order contributions are almost canceled by the rotational 1/No corrections. The results are summarized as follows: the vector and tensor K'NO coupling constants, gK*N= 0.74--0.87 and fk*N =0.53--1.16, respectively, and F→KN = 0.71 MeV, based on the result of the KN coupling constant gKne =0.83. We also show the differential cross sections and beam asymmetries, based on the present results. We also discuss the connection of present results with the original work by Diakonov, Petrov, and Polyakov.  相似文献   

18.
In this talk I report on recent work related to the dynamical generation of baryonic resonances, some made up from pseudoscalar meson-baryon, others from vector meson-baryon and a third type from two meson-one baryon systems. We can establish a correspondence with known baryonic resonances, reinforcing conclusions previously drawn and bringing new light on the nature of some baryonic resonances of higher mass.  相似文献   

19.
The dynarnically generated resonances from vector meson-baryon decuplet are studied using La- grangians of the hidden gauge theory for vector interactions. One shows that some of the generated states can be associated with some known baryon resonances in the PDG data, while others are predictions for new states. Furthermore, we calculate the radiative decay widths of these resonances into a photon and a baryon decuplet.  相似文献   

20.
A high order energy preserving scheme for a strongly coupled nonlinear Schrōdinger system is roposed by using the average vector field method. The high order energy preserving scheme is applied to simulate the soliton evolution of the strongly coupled Schrōdinger system. Numerical results show that the high order energy preserving scheme can well simulate the soliton evolution, moreover, it preserves the discrete energy of the strongly coupled nonlinear Schrōdinger system exactly.  相似文献   

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