From C*algebra extensions to CQMS, SUq(2){SU}_q(2), Podles sphere and other examples

We construct compact quantum metric spaces (CQMS) starting with some C*algebra extension with a positive splitting. As special cases we discuss the case of Toeplitz algebra, quantum SU(2) and Podles sphere

Metrics On The Quantum Heisenberg Manifold

Compact quantum metric spaces are order unit spaces along with a Lip norm. On the order unit space of the selfadjoint elements of the dense subalgebra of smooth elements in the quantum Heisenberg manifold we construct Lip norms

Connes' calculus for The Quantum double suspension

Given a spectral triple $(\mathcal{A},\mathcal{H},D)\,$ Connes associated a canonical differential graded algebra $\,\Omega_D^\bullet(\mathcal{A})$. However, so far this has been computed for very few special cases. We identify suitable hypotheses on a spectral triple that helps one to compute the associated Connes' calculus for its quantum double suspension. This allows one to compute $\,\Omega_D^\bullet$ for spectral triples obtained by iterated quatum double suspension of the spectral triple associated with a first order differential operator on a compact smooth manifold. This gives the first systematic computation of Connes' calculus for a large family of spectral triples

Gelfand-Kirillov dimension of the algebra of regular functions on quantum groups

Let $G_q$ be the $q$-deformation of a simply connected simple compact Lie group $G$ of type $A$, $C$ or $D$ and $\mathcal{O}_q(G)$ be the algebra of regular functions on $G_q$. In this article, we prove that the Gelfand-Kirillov dimension of $\mathcal{O}_q(G)$ is equal to the dimension of real manifold $G$.Comment: 15 pages. arXiv admin note: text overlap with arXiv:1709.0858

On equivariant Dirac operators for SUq(2)SU_q(2)

We explain the notion of minimality for an equivariant spectral triple and show that the triple for the quantum SU(2) group constructed by Chakraborty and Pal in \cite{c-p1} is minimal. We also give a decomposition of the spectral triple constructed by Dabrowski {\it et al} \cite{dlssv} in terms of the minimal triple constructed in \cite{c-p1}.Comment: 11 page

Characterization of SUq(ℓ+1)SU_q(\ell+1)-equivariant spectral triples for the odd dimensional quantum spheres

The quantum group $SU_q(\ell+1)$ has a canonical action on the odd dimensional sphere $S_q^{2\ell+1}$. All odd spectral triples acting on the $L_2$ space of $S_q^{2\ell+1}$ and equivariant under this action have been characterized. This characterization then leads to the construction of an optimum family of equivariant spectral triples having nontrivial $K$-homology class. These generalize the results of Chakraborty & Pal for $SU_q(2)$.Comment: LaTeX2e, 20 page

Gelfand-Kirillov dimension of some simple unitarizable modules

Let $\mathcal{O}_q(G)$ be the quantized algebra of regular functions on a semisimple simply connected compact Lie group $G$. Simple unitarizable left $\mathcal{O}_q(G)$-module are classified. In this article, we compute their Gelfand-Kirillov dimension where $G$ is of the type $A$, $C$ and $D$.Comment: 19 page

Characterization of spectral triples: A combinatorial approach

We describe a general technique to study Dirac operators on noncommutative spaces under some additional assumptions. The main idea is to capture the compact resolvent condition in a combinatorial set up. Using this, we then prove that for a certain class of representations of the C^*-algebra C(SU_q(\ell+1)), any Dirac operator that diagonalises with respect to the natural basis of the underlying Hilbert space must have trivial sign.Comment: v3: partly rewritten; the equivariant case has now been taken out and would be treated in a separate paper. v2: few typos corrected. LaTeX2e, uses xy-pic and eepi

Local index formula for the quantum double suspension

Our understanding of local index formula in noncommutative geometry is stalled for a while because we do not have more than one explicit computation, namely that of Connes for quantum SU(2) and do not understand the meaning of the various multilinear functionals involved in the formula. In such a situation further progress in understanding necessitates more explicit computations and here we execute the second explicit computation for the quantum double suspension, a construction inspired by the Toeplitz extension. More specifically we compute local index formula for the quantum double suspensions of $C(S^2)$ and the noncommutative $2$-torus.Comment: Spelling mistake in the name of second author has been rectifie

K-groups of the quantum homogeneous space SUq(n)/SUq(n−2)SU_{q}(n)/SU_{q}(n-2)

Quantum Steiffel manifolds were introduced by Vainerman and Podkolzin in \cite{VP}. They classified the irreducible representations of their underlying $C^*$-algebras. Here we compute the K groups of the quantum homogeneous spaces $SU_{q}(n)/SU_{q}(n-2), n\ge 3$. Specializing to the case $n=3$ we show that the fundamental unitary for quantum $SU(3)$ is nontrivial and is a unimodular element in $K_1$