نحن نصيح تشكيلاً كيومانتيك لمفهوم مجموعة الإحداثيات الريمانية لهذا المنحدر الريماني المضغوط، عن طريق تدخل مفهوم طبيعي للتصرف الناعم والإحداثي للمجموعة الكيومانتيكة المضغوطة على المنحدر الكلاسيكي أو غير المترادف، والتي يتم وصفها بالمثال الطيفي، ومن ثم إثبات وجود كائن عالمي (الذي يسمى مجموعة الإحداثيات الكيومانتيكة) في الفئة المضغوطة الكيومانتيكة التي تصرف ناعماً وإحداثياً على المنحدر المعطى (الذي قد لا يكون مترادفاً) والذي يلبي الشروط المناسبة. في الواقع، نحن نحدد مجموعة الإحداثيات الكيومانتيكة بالكائن العالمي في الفئة الأكبر، وهي فئة العوائل الكيومانتيكة الناعمة الطيفية، التي تعرف على طول خط Woronowicz و Soltan. كما نبني المثال الطيفي على هيلبرت سبايس المنحدر الغير مترادف الذي يكون متطابقاً مع التمثيل الوحدي الطبيعي لمجموعة الإحداثيات الكيومانتيكة. نحن نعطي وصفاً مباشراً لمجموعات الإحداثيات الكيومانتيكة للمنحدرات المترادفة وغير المترادفة، وفي هذا السياق، نحصل على المنحدر المزدوج الكيومانتيك الذي تم تعريفه في المرجع cite{hajac} كمجموعة الكيومانتيكة العالمية للإحداثيات الهولومورفية للمنحدر الغير مترادف.
We formulate a quantum generalization of the notion of the group of Riemannian isometries for a compact Riemannian manifold, by introducing a natural notion of smooth and isometric action by a compact quantum group on a classical or noncommutative manifold described by spectral triples, and then proving the existence of a universal object (called the quantum isometry group) in the category of compact quantum groups acting smoothly and isometrically on a given (possibly noncommutative) manifold satisfying certain regularity assumptions. In fact, we identify the quantum isometry group with the universal object in a bigger category, namely the category of `quantum families of smooth isometries, defined along the line of Woronowicz and Soltan. We also construct a spectral triple on the Hilbert space of forms on a noncommutative manifold which is equivariant with respect to a natural unitary representation of the quantum isometry group. We give explicit description of quantum isometry groups of commutative and noncommutative tori, and in this context, obtain the quantum double torus defined in cite{hajac} as the universal quantum group of holomorphic isometries of the noncommutative torus.
We prove a Koszul formula for the Levi-Civita connection for any pseudo-Riemannian bilinear metric on a class of centered bimodule of noncommutative one-forms. As an application to the Koszul formula, we show that our Levi-Civita connection is a bimodule connection. We construct a spectral triple on a fuzzy sphere and compute the scalar curvature for the Levi-Civita connection associated to a canonical metric.
This is the text of a series of five lectures given by the author at the Second Annual Spring Institute on Noncommutative Geometry and Operator Algebras held at Vanderbilt University in May 2004. It is meant as an overview of recent results illustrating the interplay between noncommutative geometry and arithmetic geometry/number theory.
We formulate a quantum group analogue of the group of orinetation-preserving Riemannian isometries of a compact Riemannian spin manifold, more generally, of a (possibly $R$-twisted in the sense of a paper of one of the authors, and of compact type) spectral triple. The main advantage of this formulation, which is directly in terms of the Dirac operator, is that it does not need the existence of any `good Laplacian as in our previous works on quantum isometry groups. Several interesting examples, including those coming from Rieffel-type deformation as well as the equivariant spectral triples on $SU_mu(2)$ and $S^2_{mu 0}$ are dicussed.
We review the noncommutative approach to the standard model. We start with the introduction if the mathematical concepts necessary for the definition of noncommutative spaces, and manifold in particular. This defines the framework of spectral geometry. This is applied to the standard model of particle interaction, discussing the fermionic and bosonic spectral action. The issues relating to the calculation of the mass of the Higgs are discussed, as well as the role of neutrinos and Wick rotations. Finally, we present the possibility of solving the problem of the Higgs mass by considering a pregeometric grand symmetry.
This paper presents the geometric setting of quantum variational principles and extends it to comprise the interaction between classical and quantum degrees of freedom. Euler-Poincare reduction theory is applied to the Schrodinger, Heisenberg and Wigner-Moyal dynamics of pure states. This construction leads to new variational principles for the description of mixed quantum states. The corresponding momentum map properties are presented as they arise from the underlying unitary symmetries. Finally, certain semidirect-product group structures are shown to produce new variational principles for Diracs interaction picture and the equations of hybrid classical-quantum dynamics.