Quantum 2-spheres and bigq-Jacobi polynomials

Orthogonal bases for the algebras of functions of Podles' quantum 2-spheres are explicitly determined in terms of bigq-Jacobi polynomials. This gives a group-theoretic interpretation of the symmetric bigq-Jacobi polynomials and the symmetricq-Hahn polynomials.     

The problem of differential calculus on quantum groups

The bicovariant differential calculi on quantum groups of Woronowicz have the drawback that their dimensions do not agree with that of the corresponding classical calculus. In this paper we discuss the first-order differential calculus which arises from a simple quantum Lie algebra l _h (g) This calculus has the correct dimension and is shown to be bicovariant and complete. But it doesnot satisfy the Leibniz rule. Forsl _n this approach leads to a differential calculus which satisfies a simple generalization of the Leibniz rule.Presented at the 5th International Colloquium on Quantum Groups: Quantum Groups and Integrable Systems, Prague, 20–22 June 1996.     

Big q-Jacobi polynomials,q-Hahn polynomials,and a family of quantum 3-spheres

The big q-Jacobi polynomials and the q-Hahn polynomials are realized as spherical functions on a new quantum SU _q (2)-space which can be regarded as the total space of a family of quantum 3-spheres.     

Braided differential operators on quantum algebras

We propose a general scheme of constructing braided differential algebras via algebras of “quantum exponentiated vector fields” and those of “quantum functions”. We treat a reflection equation algebra as a quantum analog of the algebra of vector fields. The role of a quantum function algebra is played by a general quantum matrix algebra. As an example we mention the so-called RTT algebra of quantized functions on the linear matrix group GL(m)$GL\left(m\right)$. In this case our construction essentially coincides with the quantum differential algebra introduced by S. Woronowicz. If the role of a quantum function algebra is played by another copy of the reflection equation algebra we get two different braided differential algebras. One of them is defined via a quantum analog of (co)adjoint vector fields, the other algebra is defined via a quantum analog of right-invariant vector fields. We show that the former algebra can be identified with a subalgebra of the latter one. Also, we show that “quantum adjoint vector fields” can be restricted to the so-called “braided orbits” which are counterparts of generic GL(m)$GL\left(m\right)$-orbits in gl^∗(m)$g{l}^{\ast }\left(m\right)$. Such braided orbits endowed with these restricted vector fields constitute a new class of braided differential algebras.     

The differential and cone structures of spacetime

We propose to model spacetime by a differential space rather than by a differential manifold. A differential space is the pair (M, C), where M is any set, and C a family of real functions on M, satisfying certain axioms; C is called a differential structure of a corresponding differential space. This concept suitably generalizes the manifold concept. We show that C can be chosen in such a way that it contains all information about the causal structure of spacetime. This information can be read out of C with the help of only one postulate, namely that physical signals travel along piecewise smooth curves in (M, C). We effectively construct the Minkowski spacetime, with its cone structure, in this way. Some comments are made.     

Classification of bicovariant differential calculi on quantum groups

Suppose thatq is not a root of unity. We classify all bicovariant differential calculi of dimension greater than one on the quantum groupsGL _q (N),O _q (N) andSp _q (N) for which the differentials du _j ⁱ of the matrix entriesu _j ⁱ generate the left module of first order forms. Our first classification theorem asserts that there are precisely two one-parameter families of such calculi onGL _q (N) forN3. In the limitq1 only two of these calculi give the ordinary differential calculus onGL(N). Our second main theorem states that apart from finitely manyq there exist precisely two differential calculi with these properties onO _q (N) andSp _q (N) forN4. This strengthens the corresponding result proved in our previous paper [SS2]. There are four such calculi onO _q (3). We introduce two new 4-dimensional bicovariant differential calculi onO _q (3).     

Bibliography on quantum logics and related structures

The bibliography contains 1851 references on axiomatic structures underlying quantum mechanics, with stress on varieties of algebraico-logical, probabilistic, and operational structures for which the term quantum logics is adopted. An index of about 250 keywords picked out from the titles is included and statistics about papers, journals, and authors are presented. Monographs and proceedings on the subject are noted.     

Bound polaron in quantum dot quantum well structures

The problem of bound polarons in quantum dot quantum well (QDQW) structures is studied theoretically. The eigenfrequencies of bulk longitudinal optical (LO) and surface optical (SO) modes are derived in the framework of the dielectric continuum approximation. The electron--phonon interaction Hamiltonian for QDQW structures is obtained and the exchange interaction between impurity and LO-phonons is discussed. The binding energy and the trapping energy of the bound polaron in CdS/HgS QDQW structures are calculated. The numerical results reveal that there exist three branches of eigenfrequencies of surface optical vibration in the CdS/HgS QDQW structure. It is also shown that the binding energy and the trapping energy increase as the inner radius of the QDQW structure decreases, with the outer radius fixed, and the trapping energy takes a major part of the binding energy when the inner radius is very small.     

A classification of quantum Hall fluids

In this paper, the key ideas of characterizing universality classes of dissipationfree (incompressible) quantum Hall fluids by mathematical objects called quantum Hall lattices are reviewed. Many general theorems about the classification of quantum Hall lattices are stated and their physical implications are discussed. Physically relevant subclasses of quantum Hall lattices are defined and completely classified. The results are carefully compared with experimental data and also with other theoretical schemes (the hierarchy schemes). Several proposals for new experiments are made which could help to settle interesting issues in the theory of the (fractional) quantum Hall effect and thus would lead to a deeper understanding of this remarkable effect.     

A classification of space-time structures

The paper contains a review of various bundles which may be associated to the bundle of linear frames and used to describe properties of space relevant to physics. Restrictions, extensions, prolongations and reductions are defined in terms of morphisms of principal bundles. It is shown that the holonomic prolongation of a G-structure exist iff the corresponding structure function vanishes. G-connections are related to restrictions of the bundle of second-order frames. It is shown that these restrictions may be used to classify theories of space-time and gravitation. A distinction is made between a projective connection and a geodetic structure. In the framework of the Einstein-Cartan theory, the projective connection of a space-time is compatible with its metric tensor iff the spin density is bivector-valued. As an example, we mention a new theory of gravitation and electromagnetism based on the Weyl-Cartan structure of space-time and on the Yang quadratic Lagrangian.     

Lipschitzian quantum stochastic differential inclusions

Quantum stochastic differential inclusions are introduced and studied within the framework of the Hudson-Parthasarathy formulation of quantum stochastic calculus. Results concerning the existence of solutions of a Lipschitzian quantum stochastic differential inclusion and the relationship between the solutions of such an inclusion and those of its convexification are presented. These generalize the Filippov existence theorem and the Filippov-Waewski relaxation theorem for classical differential inclusions to the present noncommutative setting.     

N=2 structures on solvable Lie algebras: Thec=9 classification

Let be a finite-dimensional Lie algebra (not necessarily semisimple). It is known that if is self-dual (that is, if it possesses an invariant metric) then it admits anN=1 (affine) Sugawara construction. Under certain additional hypotheses, thisN=1 structure admits anN=2 extension. If this is the case, is said to possess anN=2 structure. It is also known that anN=2 structure on a self-dual Lie algebra is equivalent to a vector space decomposition , where are isotropic Lie subalgebras. In other words,N=2 structures on in one-to-one correspondence with Manin triples . In this paper we exploit this correspondence to obtain a classification of thec=9N=2 structures on solvable Lie algebras. In the process we also give some simple proofs for a variety of Lie algebras. In the process we also give some simple proofs for a variety of Lie algebraic results concerning self-dual Lie algebras admitting symplectic or Kähler structures.     

碰撞转动传能的量子干涉效应中微分干涉角的研究

转动传能的量子干涉效应在静态池实验中发现,并且已测得积分干涉角.为了得到更多关于传能的准确信息,应利用分子束进行实验.本文基于一阶含时波恩近似,模拟了利用分子束实验进行量子干涉效应研究的理论模型.此模型采用了Lennard-Jones相互作用势和直线轨道近似.通过本文建立的模型,研究了影响干涉效应的微分干涉角的因素,并且得到了徽分干涉角和碰撞速度、碰撞参数及碰撞体的关系.此理论模型对于指导分子束实验具有重要的意义.     

The differential interference angle in collisional quantum interference on rotational energy transfer

Collisional quantum interference （CQI） in the intramolecular rotational energy transfer was observed in experiment by Sha and co-workers. The interference angle, which measuring the degree of the coherence, were measured in the experiment of the static cell. Based on the first Born approximation of time dependent perturbation theory, taking into accounts the anisotropic Lennard-Jones interaction potentials, this paper describes the theoretical model of CQI in intramolecular rotational energy transfer in an atom-diatom collision system. In the model, the differential interference angle for the experiment of the molecular beam is calculated, the changing tendencies of the differential interference angle with the impact parameter and collision partners are obtained. This theoretical model is important for understanding or performing this kind of experiments.     

Bicovariant differential geometry of the quantum group SL h (2)

There are only two quantum group structures on the space of two by two unimodular matrices, these are the SL _q (2) and the SL _h (2) quantum groups. The differential geometry of SL _q (2) is well known. In this Letter, we develop the differential geometry of SL _h (2), and show that the space of left invariant vector fields is three-dimensional.     

Topological classification of impulsive differential equations

The present paper is concerned with the topological classification of impulsive differential equations. Under the assumption that the linear part of the right-hand side of the equation considered has an exponential dichotomy and the nonlinear perturbation is small enough, it is proved that for the underlying equations there existN + 1 types topologically different from one another.     

A problem of classification of quantum groups

An attempt to formulate a precise program of classification of a large family of quantum groups is presented. This family includes the familiar quantum groups and quantum supergroups, but much more, all unified in a very simple structure. The emphasis is on the logic of the classification scheme. Recent results are reported without much explanation and proofs are described only in a general way.