排序方式: 共有58条查询结果,搜索用时 31 毫秒
1.
We show that three dimensional Chern-Simons gauge theories with a compact gauge groupG (not necessarily connected or simply connected) can be classified by the integer cohomology groupH
4(BG,Z). In a similar way, possible Wess-Zumino interactions of such a groupG are classified byH
3(G,Z). The relation between three dimensional Chern-Simons gauge theory and two dimensional sigma models involves a certain natural map fromH
4(BG,Z) toH
3(G,Z). We generalize this correspondence to topological spin theories, which are defined on three manifolds with spin structure, and are related to what might be calledZ
2 graded chiral algebras (or chiral superalgebras) in two dimensions. Finally we discuss in some detail the formulation of these topological gauge theories for the special case of a finite group, establishing links with two dimensional (holomorphic) orbifold models. 相似文献
2.
Robbert Dijkgraaf Erik Verlinde Herman Verlinde 《Communications in Mathematical Physics》1988,115(4):649-690
We study the theory ofc=1 torus and 2-orbifold models on general Riemann surfaces. The operator content and occurrence of multi-critical points in this class of theories is discussed. The partition functions and correlation functions of vertex operators and twist fields are calculated using the theory of double covered Riemann surfaces. It is shown that orbifold partition functions are sensitive to the Torelli group. We give an algebraic construction of the operator formulation of these nonchiral theories on higher genus surfaces. Modular transformations are naturally incorporated as canonical transformations in the Hilbert space. 相似文献
3.
Camille Descour Tibor Macko Dario Cavallo Matthew Parkinson Gerhard Hubner Anne Spoelstra Maurizio Villani Robbert Duchateau 《Journal of polymer science. Part A, Polymer chemistry》2014,52(10):1422-1434
Stereoblock polypropylenes comprising of iPP and sPP segments are synthesized by polymerization of the following binary system of metallocenes: the Cs‐symmetric [2,7‐t‐Bu2(Flu)2Ph2C(Cp)ZrCl2] and the C2‐symmetric rac‐Me2Si(2‐Me‐4‐Ph‐Ind)2ZrCl2. Blends of samples made either by each catalyst individually (solution blend) with materials obtained with the mixed catalyst system (reactor blend) are compared. The simultaneous presence of MAO and DEZ, enhancing fast and reversible transfer of the growing chains between the two active centers, leads to the formation of a stereoblock microstructure. In this case, low molecular weight polymers are obtained. The junction between the blocks is qualitatively observed in 13C NMR. When made in toluene, the stereoblock material consists of a majority of syndiotactic sequences, whereas the ratio is more equilibrated when the polymerization was conducted in the more polar chlorobenzene. This is confirmed by the results obtained with 13C NMR, CRYSTAF, HT HPLC, DSC, SSA, WAXD, and optical microscopy. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1422–1434 相似文献
4.
5.
Jan M. Aarts Robbert J. Fokkink 《Proceedings of the American Mathematical Society》2001,129(9):2803-2807
There is a close relation between the color number of a continuous map without fixed points and the topological dimension. If is an involution, the color number is also related to the co-index. An addition theorem for the color number is established thus underscoring the interrelations between color number, dimension and co-index.
6.
We study the relation between perturbative knot invariants and the free energies defined by topological string theory on the character variety of the knot. Such a correspondence between SL(2;C) Chern–Simons gauge theory and the topological open string theory was proposed earlier on the basis of the volume conjecture and AJ conjecture. In this paper we discuss this correspondence beyond the subleading order in the perturbative expansion on both sides. In the computation of the perturbative invariants for the hyperbolic 3-manifold, we adopt the state integral model for the hyperbolic knots, and the factorized AJ conjecture for the torus knots. On the other hand, we iteratively compute the free energies on the character variety using the Eynard–Orantin topological recursion relation. We discuss the correspondence for the figure eight knot complement and the once punctured torus bundle over S1 with the monodromy L2R up to the fifth order. For the torus knots, we find trivial the recursion relations on both sides. 相似文献
7.
Via compactification on a circle, the matrix mode] of M-theory proposed by Banks et a]. suggests a concrete identification between the large N limit of two-dimensional N = 8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states. 相似文献
8.
Robbert van Putten Evgeny A. Uslamin Marcel Garbe Chong Liu Dr. Angela Gonzalez-de-Castro Dr. Martin Lutz Dr. Kathrin Junge Prof. Dr. Emiel J. M. Hensen Prof. Dr. Matthias Beller Dr. Laurent Lefort Prof. Dr. Evgeny A. Pidko 《Angewandte Chemie (International ed. in English)》2017,56(26):7531-7534
Catalytic hydrogenation of carboxylic acid esters is essential for the green production of pharmaceuticals, fragrances, and fine chemicals. Herein, we report the efficient hydrogenation of esters with manganese catalysts based on simple bidentate aminophosphine ligands. Monoligated Mn PN complexes are particularly active for the conversion of esters into the corresponding alcohols at Mn concentrations as low as 0.2 mol % in the presence of sub-stoichiometric amounts of KOtBu base. 相似文献
9.
10.
Robbert Dijkgraaf Gregory Moore Erik Verlinde Herman Verlinde 《Communications in Mathematical Physics》1997,185(1):197-209
In this note we prove an identity that equates the elliptic genus partition function of a supersymmetric sigma model on the
N-fold symmetric product of a manifold M to the partition function of a second quantized string theory on the space . The generating function of these elliptic genera is shown to be (almost) an automorphic form for . In the context of D-brane dynamics, this result gives a precise computation of the free energy of a gas of D-strings inside
a higher-dimensional brane.
Received: Received: 16 August 1996 / Accepted: 3 October 1996 相似文献