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【期刊论文】Fermion Absorption Cross Section and Topology of Spherically Symmetric Black Holes
刘玉孝, Yu-Xiao Liu, Li Zhao, Zhen-Bin Cao, and Yi-Shi Duan
,-0001,():
-1年11月30日
In 1997, Liberati and Pollifrone in Phys. Rev. D56 (1997) 6458 (hep-th/9708014) achieved a new formulation of the Bekenstein-Hawking formula, where the entropy and the Euler characteristic are related by S = A/8. In this work we present a relation between the low-energy absorption cross section for minimally coupled fermions and the Euler characteristic of (3+1)-dimensional spherically symmetric black holes, i.e.=g−1 h A. Based on the relation, using the Gauss–Bonnet–Chern theorem and the -mapping method, an absorption cross section density is introduced to describe the topology of the absorption cross section. It is shown that the absorption cross section and its density are determined by the singularities of the timelike Killing vector field of the spacetime and these singularities carry the topological numbers, Hopf indices and Brouwer degrees, naturally.
Black holes, absorption cross section, Euler characteristic.,
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刘玉孝, Zhen-Hua Zhao, Yu-Xiao Liu†, Xi-Guo Lee
,-0001,():
-1年11月30日
The first order perturbations of the energy levels of a stationary hydrogen atom in static external gravitational field, with Schwarzschild metric, are investigated. The energy shifts are calculated for the relativistic 1S, 2S, 2P, 3S, 3P, 3D, 4S, 4P, 4D and 4F levels. The results show that the energy-level shifts of the states with total angular momentum quantum number 1/2 are all zero, and the ratio of absolute energy shifts with total angular momentum quantum number 5/2 is 1:4:5. This feature can be used to help us to distinguish the gravitational effect from other effect.
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【期刊论文】Knotted Solitons in a Charged Two-Condensate Bose System
刘玉孝, Yishi Duan, Xinhui Zhang, ∗ Yuxiao Liu, and Li Zhao
,-0001,():
-1年11月30日
By making use of the decomposition of U(1) gauge potential theory and the-mapping method,we propose that a charged two-condensate Bose system possesses vortex lines and two classes of knotted solitons. The topological charges of the vortex lines are characterized by the Hopf indices and the Brower degrees of-mapping, and the knotted solitons are described by the nontrivial Hopf invariant and the BF action, respectively.
Two-Condensate Bose System,, Vortex Lines.,
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【期刊论文】Spinor Field Realizations of Non-critical W2,s Strings
刘玉孝, Y. S. Duan† Y. X. Liu‡ L. J. Zhang§
,-0001,():
-1年11月30日
In this paper, we construct the nilpotent Becchi-Rouet-Stora-Tyutin(BRST) charges of spinor non-critical W2,s strings. The cases of s = 3, 4 are discussed in detail, and spinor realization for s = 4 is given explicitly. The BRST charges are graded.
Wstring,, BRST charge,, Non-critical string,, Spinor realization.,
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【期刊论文】Fermions on thick branes in the background of sine-Gordon kinks
刘玉孝, Yu-Xiao Liu, , * Li-Da Zhang, + Li-Jie Zhang, ‡ and Yi-Shi Duan, x
,-0001,():
-1年11月30日
A class of thick branes in the background of sine-Gordon kinks with a scalar potential V(φ)=p(1+cos) was constructed by R. Koley and S. Kar [Classical Quantum Gravity 22, 753 (2005)]. In this paper, in the background of the warped geometry, we investigate the issue of localization of spin-1=2 fermions on these branes in the presence of two types of scalar-fermion couplings: and sin. By presenting the mass-independent potentials in the corresponding Schro¨dinger equations, we obtain the lowest Kaluza-Klein modes and a continuous gapless spectrum of Kaluza-Klein states with m2>0 for both types of couplings. For the Yukawa coupling, the effective potential of the right chiral fermions for positive q and is always positive; hence only the effective potential of the left chiral fermions could trap the corresponding zero mode. This is a well-known conclusion which is discussed extensively in the literature. However, for the coupling sin, the effective potential of the right chiral fermions for positive q and is no longer always positive. Although the value of the potential at the location of the brane is still positive, it has a series of wells and barriers on each side, which ensures that the right chiral fermion zero mode could be trapped. Thus we may draw the following remarkable conclusion: for positive and q,the potentials of both the left and right chiral fermions could trap the corresponding zero modes under certain restrictions.
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