首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
In this paper, we give a general discussion on the calculation of the statistical distribution from a given operator relation of creation, annihilation, and number operators. Our result shows that as long as the relation between the number operator and the creation and annihilation operators can be expressed as ab=Λ(N)ab=Λ(N) or N=Λ−1(ab)N=Λ1(ab), where NN, aa, and bb denote the number, creation, and annihilation operators, i.e., NN is a function of quadratic product of the creation and annihilation operators, the corresponding statistical distribution is the Gentile distribution, a statistical distribution in which the maximum occupation number is an arbitrary integer. As examples, we discuss the statistical distributions corresponding to various operator relations. In particular, besides the Bose–Einstein and Fermi–Dirac cases, we discuss the statistical distributions for various schemes of intermediate statistics, especially various qq-deformation schemes. Our result shows that the statistical distributions corresponding to various qq-deformation schemes are various Gentile distributions with different maximum occupation numbers which are determined by the deformation parameter qq. This result shows that the results given in much literature on the qq-deformation distribution are inaccurate or incomplete.  相似文献   

8.
9.
Using the recent results for the two-parton light-cone distribution amplitudes of the tensor meson, we calculate the form factors for the decays of Bu,d,sBu,d,s into the light JPC=2++JPC=2++ tensor mesons via the vector/axial–vector/tensor current with the light-cone sum rules. We also obtain the q2q2-dependence of the form factors.  相似文献   

10.
We consider a Schrödinger differential expression L=ΔA+qL=ΔA+q on a complete Riemannian manifold (M,g)(M,g) with metric gg, where ΔAΔA is the magnetic Laplacian on MM and q≥0q0 is a locally square integrable function on MM. In the terminology of W.N. Everitt and M. Giertz, the differential expression LL is said to be separated in L2(M)L2(M) if for all u∈L2(M)uL2(M) such that Lu∈L2(M)LuL2(M), we have qu∈L2(M)quL2(M). We give sufficient conditions for LL to be separated in L2(M)L2(M).  相似文献   

11.
12.
13.
It was argued in [Y. Maeda, A. Sako, Noncommutative deformation of instantons, J. Geom. Phys. 58 (2008) 1784] that the noncommutative deformation of instantons on a 4-torus T4T4 should alter the instanton numbers for arbitrary noncommutativity parameter θθ. We show that this is not the case for the U(N2)U(N2) theory discussed there. And we discuss the instanton numbers in general gauge theories on the noncommutative T4T4.  相似文献   

14.
15.
Numerous non-standard dynamics are described by contact-like effective interactions that can manifest themselves in electron–positron collisions only through deviations of the observables (cross sections, asymmetries) from the Standard Model predictions. If such a deviation were observed, it would be important to identify the actual source among the possible non-standard interactions as many different new physics scenarios may lead to very similar experimental signatures. We study the possibility of uniquely identifying the indirect effects of s-channel sneutrino exchange, as predicted by supersymmetric theories with R  -parity violation, against other new physics scenarios in high-energy e+ee+e annihilation into lepton pairs at the International Linear Collider. These competitive models are interactions based on gravity in large and in TeV-scale extra dimensions, anomalous gauge couplings, ZZ vector bosons and compositeness-inspired four-fermion contact interactions. To evaluate the identification reach on sneutrino exchange, we use as basic observable a double polarization asymmetry, that is particularly suitable to directly test for such s-channel sneutrino exchange effects in the data analysis. The availability of both beams being polarized plays a crucial rôle in identifying the new physics scenario.  相似文献   

16.
17.
We propose methods towards a systematic determination of d  -dimensional curved spaces where Euclidean field theories with rigid supersymmetry can be defined. The analysis is carried out from a group theory as well as from a supergravity point of view. In particular, by using appropriate gauged supergravities in various dimensions we show that supersymmetry can be defined in conformally flat spaces, such as non-compact hyperboloids Hn+1Hn+1 and compact spheres SnSn or – by turning on appropriate Wilson lines corresponding to R-symmetry vector fields – on S1×SnS1×Sn, with n<6n<6. By group theory arguments we show that Euclidean field theories with rigid supersymmetry cannot be consistently defined on round spheres SdSd if d>5d>5 (despite the existence of Killing spinors). We also show that distorted spheres and certain orbifolds are also allowed by the group theory classification.  相似文献   

18.
We present explicit constructions of complete Ricci-flat Kähler metrics that are asymptotic to cones over non-regular Sasaki–Einstein manifolds. The metrics are constructed from a complete Kähler–Einstein manifold (V,gV)(V,gV) of positive Ricci curvature and admit a Hamiltonian two-form of order two. We obtain Ricci-flat Kähler metrics on the total spaces of (i) holomorphic C2/ZpC2/Zp orbifold fibrations over VV, (ii) holomorphic orbifold fibrations over weighted projective spaces WCP1WCP1, with generic fibres being the canonical complex cone over VV, and (iii) the canonical orbifold line bundle over a family of Fano orbifolds. As special cases, we also obtain smooth complete Ricci-flat Kähler metrics on the total spaces of (a) rank two holomorphic vector bundles over VV, and (b) the canonical line bundle over a family of geometrically ruled Fano manifolds with base VV. When V=CP1V=CP1 our results give Ricci-flat Kähler orbifold metrics on various toric partial resolutions of the cone over the Sasaki–Einstein manifolds Yp,qYp,q.  相似文献   

19.
20.
We investigate a model in which spinors are considered as being embedded within the Clifford algebra that operates on them. In Minkowski space M1,3M1,3, we have four independent 4-component spinors, each living in a different minimal left ideal of Cl(1,3)Cl(1,3). We show that under space inversion, a spinor of one left ideal transforms into a spinor of another left ideal. This brings novel insight to the role of chirality in weak interactions. We demonstrate the latter role by considering an action for a generalized spinor field ψαiψαi that has not only a spinor index α but also an extra index i   running over four ideals. The covariant derivative of ψαiψαi contains the generalized spin connection, the extra components of which are interpreted as the SU(2) gauge fields of weak interactions and their generalization. We thus arrive at a system that is left–right symmetric due to the presence of a “parallel sector”, postulated a long time ago, that contains mirror particles coupled to mirror SU(2) gauge fields.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号