共查询到20条相似文献,搜索用时 15 毫秒
1.
We use equivariant methods to define and study the orbifold K-theory of an orbifold X. Adapting techniques from equivariant K-theory, we construct a Chern character and exhibit a multiplicative decomposition
for K
*
orb
(X)⊗ℚ, in particular showing that it is additively isomorphic to the orbifold cohomology of X. A number of examples are provided. We then use the theory of projective representations to define the notion of twisted
orbifold K–theory in the presence of discrete torsion. An explicit expression for this is obtained in the case of a global
quotient.
Received: 21 August 2001 / Accepted: 27 January 2003
Published online: 13 May 2003
RID="*"
ID="*" Both authors were partially supported by the NSF
RID="*"
ID="*" Both authors were partially supported by the NSF
Communicated by R.H. Dijkgraaf 相似文献
2.
Peter Bouwknegt Alan L. Carey Varghese Mathai Michael K. Murray Danny Stevenson 《Communications in Mathematical Physics》2002,228(1):17-49
In this note we introduce the notion of bundle gerbe K-theory and investigate the relation to twisted K-theory. We provide some examples. Possible applications of bundle gerbe K-theory to the classification of K-brane charges in nontrivial backgrounds are briefly discussed.
Received: 29 June 2001 / Accepted: 15 October 2001 相似文献
3.
Kiyonori Gomi 《Communications in Mathematical Physics》2010,294(3):863-889
We provide a finite-dimensional model of the twisted K-group twisted by any degree three integral cohomology class of a CW complex. One key to the model is Furuta’s generalized vector bundle, and the other is a finite-dimensional approximation of Fredholm operators. 相似文献
4.
We study the structure of abelian extensions of the group L
q
G of q-differentiable loops (in the Sobolev sense), generalizing from the case of the central extension of the smooth loop group.
This is motivated by the aim of understanding the problems with current algebras in higher dimensions. Highest weight modules
are constructed for the Lie algebra. The construction is extended to the current algebra of the supersymmetric Wess-Zumino-Witten
model. An application to the twisted K-theory on G is discussed. 相似文献
5.
In this paper we construct an explicit geometric model for the group of gerbes over an orbifold X. We show how from its curvature we can obtain its characteristic class in H3(X) via Chern-Weil theory. For an arbitrary gerbe , a twisting Korb(X) of the orbifold K-theory of X is constructed, and shown to generalize previous twisting by Rosenberg [28], Witten [35], Atiyah-Segal [2] and Bowknegt et. al. [4] in the smooth case and by Adem-Ruan [1] for discrete torsion on an orbifold.The first author was partially supported by the National Science Foundation and Conacyt-México 相似文献
6.
It was argued in [25, 5] that in the presence of a nontrivial B-field, D-brane charges in type IIB string theories are classified by twisted K-theory. In [4], it was proved that twisted K-theory is canonically isomorphic to bundle gerbe K-theory, whose elements are ordinary Hilbert bundles on a principal projective unitary bundle, with an action of the bundle
gerbe determined by the principal projective unitary bundle. The principal projective unitary bundle is in turn determined
by the twist. This paper studies in detail the Chern-Weil representative of the Chern character of bundle gerbe K-theory that was introduced in [4], extending the construction to the equivariant and the holomorphic cases. Included is a
discussion of interesting examples.
Received: 10 January 2002 / Accepted: 9 December 2002
Published online: 25 February 2003
RID="⋆"
ID="⋆" The authors acknowledge the support of the Australian Research Council
Communicated by R.H. Dijkgraaf 相似文献
7.
Sergei Gukov 《Communications in Mathematical Physics》2000,210(3):621-639
We use equivariant K-theory to classify charges of new (possibly non-supersymmetric) states localized on various orientifolds in Type II string theory. We also comment on the stringy construction of new D-branes and demonstrate the discrete electric-magnetic duality in Type I brane systems with p+q=7, as proposed by Witten. 相似文献
8.
9.
Charles Doran Stefan Méndez-Diez Jonathan Rosenberg 《Letters in Mathematical Physics》2014,104(11):1333-1364
D-brane charges in orientifold string theories are classified by the KR-theory of Atiyah. However, this is assuming that all O-planes have the same sign. When there are O-planes of different signs, physics demands a “KR-theory with a sign choice” which up until now has not been studied by mathematicians (with the unique exception of Moutuou, who did not have a specific application in mind). We give a definition of this theory and compute it for orientifold theories compactified on S 1 and T 2. We also explain how and why additional “twisting” is implemented. We show that our results satisfy all possible T-duality relationships for orientifold string theories on elliptic curves, which will be studied further in subsequent work. 相似文献
10.
Motivated by examples obtained from conformal deformations of spectral triples and a spectral triple construction on quantum cones, we propose a new twisted reality condition for the Dirac operator. 相似文献
11.
A new type of nonlocal currents (quasi-particles), which we call twisted parafermions, and its corresponding twisted Z-algebra are found. The system consists of one spin-1 bosonic field and six nonlocal fields of fractional spins. Jacobi-type identities for the twisted parafermions are derived, and a new conformal field theory is constructed from these currents. As an application, a parafermionic representation of the twisted affine current algebra A(2)2 is given. 相似文献
12.
13.
14.
We consider the Dirichlet Laplacian \(H_\gamma \) on a 3D twisted waveguide with random Anderson-type twisting \(\gamma \). We introduce the integrated density of states \(N_\gamma \) for the operator \(H_\gamma \), and investigate the Lifshits tails of \(N_\gamma \), i.e. the asymptotic behavior of \(N_\gamma (E)\) as \(E \downarrow \inf \mathrm{supp}\, dN_\gamma \). In particular, we study the dependence of the Lifshits exponent on the decay rate of the single-site twisting at infinity. 相似文献
15.
Eltsov VB Finne AP Hänninen R Kopu J Krusius M Tsubota M Thuneberg EV 《Physical review letters》2006,96(21):215302
We study a twisted vortex bundle where quantized vortices form helices circling around the axis of the bundle in a "force-free" configuration. Such a state is created by injecting vortices into a rotating vortex-free superfluid. Using continuum theory we determine the structure and the relaxation of the twisted state. This is confirmed by numerical calculations. We also present experimental evidence of the twisted vortex state in superfluid 3He-B. 相似文献
16.
We introduce a twisted version of the Heisenberg double, constructed from a twisted Hopf algebra and a twisted pairing. We state a Stone–von Neumann type theorem for a natural Fock space representation of this twisted Heisenberg double and deduce the effect on the algebra of shifting the product and coproduct of the original twisted Hopf algebra. We conclude by showing that the quantum Weyl algebra, quantum Heisenberg algebras, and lattice Heisenberg algebras are all examples of the general construction. 相似文献
17.
Paolo Aschieri Marija Dimitrijević Frank Meyer Stefan Schraml Julius Wess 《Letters in Mathematical Physics》2006,78(1):61-71
Gauge theories on a space-time that is deformed by the Moyal–Weyl product are constructed by twisting the coproduct for gauge transformations. This way a deformed Leibniz rule is obtained, which is used to construct gauge invariant quantities. The connection will be enveloping algebra valued in a particular representation of the Lie algebra. This gives rise to additional fields, which couple only weakly via the deformation parameter θ and reduce in the commutative limit to free fields. Consistent field equations that lead to conservation laws are derived and some properties of such theories are discussed. 相似文献
18.
The construction of twisted K-theory classes on a compact Lie group is reviewed using the supersymmetric Wess-Zumino-Witten
model on a cylinder. The Quillen superconnection is introduced for a family of supercharges parametrized by a compact Lie
group and the Chern character is explicitly computed in the case of SU(2). For large euclidean time, the character form is localized on a D-brane. 相似文献
19.
We study D-branes and Ramond-Ramond fields on global orbifolds of Type II string theory with vanishing H-flux using methods of equivariant K-theory and K-homology. We illustrate how Bredon equivariant cohomology naturally realizes
stringy orbifold cohomology. We emphasize its role as the correct cohomological tool which captures known features of the
low-energy effective field theory, and which provides new consistency conditions for fractional D-branes and Ramond-Ramond
fields on orbifolds. We use an equivariant Chern character from equivariant K-theory to Bredon cohomology to define new Ramond-Ramond
couplings of D-branes which generalize previous examples. We propose a definition for groups of differential characters associated
to equivariant K-theory. We derive a Dirac quantization rule for Ramond-Ramond fluxes, and study flat Ramond-Ramond potentials
on orbifolds. 相似文献
20.
Assuming the existence of the perfect crystal bases of Kirillov-Reshetikhin modules over simply-laced quantum affine algebras,
we construct certain perfect crystals for twisted quantum affine algebras, and also provide compelling evidence that the constructed
crystals are isomorphic to the conjectural crystal bases of Kirillov-Reshetikhin modules over twisted quantum affine algebras. 相似文献