Algebraic Conformal Field Theories II

Some mathematical questions relating to Coset Conformal Field Theories (CFT) are considered in the framework of Algebraic Quantum Field Theory as developed previously by us. We consider the issue of fixed point resolution in the diagonal coset of type A, and show how to decompose reducible representations into irreducibles. We show the corresponding coset CFT gives rise to a unitary tensor modular category in the sense of Turaev, and therefore may be used to construct 3-manifold invariants. We also show that Kac-Wakimoto Hypothesis (KWH) and Kac-Wakimoto Conjecture (KWC) are equivalent under general conditions which can be checked in examples, a result which seems to be hard to prove by purely representation considerations. Examples are also presented.Comment: 24 pages, AMSte

Algebraic Coset Conformal field theories

All unitary Rational Conformal Field Theories (RCFT) are conjectured to be related to unitary coset Conformal Field Theories, i.e., gauged Wess-Zumino-Witten (WZW) models with compact gauge groups. In this paper we use subfactor theory and ideas of algebraic quantum field theory to approach coset Conformal Field Theories. Two conjectures are formulated and their consequences are discussed. Some results are presented which prove the conjectures in special cases. In particular, one of the results states that a class of representations of coset $W_N$ ($N\geq 3$) algebras with critical parameters are irreducible, and under the natural compositions (Connes' fusion), they generate a finite dimensional fusion ring whose structure constants are completely determined, thus proving a long-standing conjecture about the representations of these algebras.Comment: 49 pages, Improved presentations and added details, to appear in Comm.Math.Phy

Recent progress in applying lattice QCD to kaon physics

Standard lattice calculations in kaon physics are based on the evaluation of matrix elements of local operators between two single-hadron states or a single-hadron state and the vacuum. Recent progress in lattice QCD has gone beyond these standard observables. I will review the status and prospects of lattice kaon physics with an emphasis on non-leptonic $K\to\pi\pi$ decay and long-distance processes including $K^0$-$\overline{K^0}$ mixing and rare kaon decays.Comment: 23 pages, 13 figures, 3 tables; Plenary talk given at Lattice 201

On representing some lattices as lattices of intermediate subfactors of finite index

We prove that the very simple lattices which consist of a largest, a smallest and $2n$ pairwise incomparable elements where $n$ is a positive integer can be realized as the lattices of intermediate subfactors of finite index and finite depth. Using the same techniques, we give a necessary and sufficient condition for subfactors coming from Loop groups of type $A$ at generic levels to be maximal.Comment: 39 pages, latex, corrected proof of Cor. 5.23. To appear in Advance in Mathematic