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We define some new invariants for 3-manifolds using the space of taut codim-1 foliations along with various techniques from noncommutative geometry. These invariants originate from our attempt to generalise Topological Quantum Field Theories in the Noncommutative geometry / topology realm., Comment: 7 pages

We present a method to develop a Hodge theory for tangential cohomology of foliations by mimicing Witten's approach to ordinary Morse theory by perturbations of the Laplacian, Comment: 4 pages, references addded. arXiv admin note: text overlap with arXiv:1401.4080

We present some ideas for a possible Noncommutative Topological Quantum Field Theory (NCTQFT) and Noncommutative Floer Homology (NCFH). Our motivation is two-fold and it comes both from physics and mathematics: On the one hand we argue that NCTQFT is the correct mathematical framework for a quantum field theory of all known interactions in nature (including gravity). On the other hand we hope that a possible NCFH will apply to practically every 3-manifold (and not only to homology 3-spheres as ordinary Floer Homology currently does). The two motivations are closely related since, at least in the commutative case, Floer Homology Groups constitute the space of quantum observables of (3+1)-dim Topological Quantum Field Theory. Towards this goal we present some "Noncommutative" Versions of Hodge Theory for noncommutative differentail forms and tangential cohomology for foliations., Comment: 31 pages. Extended version of two talks presented during the International Conference on Mathematical Modeling in Physical Sciences, 1-5 September 2013, Prague, Czech Republic

We study both the short term and long term effects of solar activity on the large transformers (150kV and 400kV) of the Greek national electric grid. We use data analysis and various analytic and statistical methods and models. Contrary to the common belief in PPC Greece, we see that there are considerable both short term (immediate) and long term effects of solar activity onto large transformers in a mid-latitude country (latitude approx. 35 - 41 degrees North) like Greece. Our results can be summarized as follows: For the short term effects: During 1989-2010 there were 43 stormy days (namely days with for example Ap larger or equal to 100) and we had 19 failures occurring during a stormy day plus or minus 3 days and 51 failures occurring during a stormy day plus or minus 7 days. All these failures can be directly related to Geomagnetically Induced Currents (GICs). Explicit cases are presented. For the long term effects we have two main results: The annual transformer failure number for the period of study 1989-2010 follows the solar activity pattern (11 year periodicity, bell-shaped graph). Yet the maximum number of transformer failures occur 3-4 years after the maximum of solar activity. There is statistical correlation between solar activity expressed using various newly defined long term solar activity indices and the annual number of transformer failures. These new long term solar activity indices were defined using both local (from geomagnetic stations in Greece) and global (planetary averages) geomagnetic data. Applying both linear and non-linear statistical regression we compute the regression equations and the corresponding coefficients of determination., Comment: 45 pages,a summary will be presented at the International Conference on Mathematical Modeling in Physical Sciences, 1-5 September 2013, Prague, Czech Republic.Some preliminary results were presented during the 8th European Space Weather Week in Namur, Belgium, 2011. Another part was presented at the 9th European Space Weather Week at the Acad\'emie Royale de Belgique, Brussels, Belgium 2012

The motivation for this article came from an attempt to give an alternative definition for the meter, the SI unit for measuring length. As a starting point towards this goal, in this piece of work we present the underlying theory behind our approach which uses ideas from quantum field theory and noncommutative geometry, in particular the notion of an odd K-cycle which is based on the Dirac operator (and its inverse, the Dirac propagator). Using (the perhaps more familiar) physics terminology, the key point in our strategy is this: instead of measuring length directly in space-time we measure the "algebraic (spectral) length" in the space of the corresponding quantum states of some particle (fermion) acted upon by the Dirac propagator. This approach shares the spirit of the unanimus vote of the 24th General Conference of Standards and Measures (21st October 2011) in Serves, France for the redefinition of the fundamental units using Planck's constant., Comment: Extended version of an invited talk during the 4th Tactical Conference on Metrology, 3-4 February 2012, National Technical University of Athens, Athens Greece

We present 18 Introductory Lectures on K-Theory covering its basic three branches, namely topological, analytic (K-Homology) and Higher Algebraic K-Theory, 6 lectures on each branch. The skeleton of these notes was provided by the author's personal notes from a graduate summer school on K-Theory organised by the London Mathematical Society (LMS) back in 1995 in Lancaster, UK., Comment: 137 pages, contains an Appendix with basic results from algebraic topology, functional analysis and homological algebra

This article presents some computations for a new topological invariant for foliations introduced some years ago by the author using techniques from noncommutative geometry, in particular the pairing between K-Theory and cyclic cohomology. The motivation came from theoretical physics, more specifically from flat vector bundles, in physics terminology from potentials which are pure gauge., Comment: 15 pages

We shall try to exhibit a relation between black hole entropy and topological entropy using the famous Baum-Connes conjecture for foliated manifolds which are particular examples of noncommutative spaces. Our argument is qualitative and it is based on the microscopic origin of the Beckenstein-Hawking area-entropy formula for black holes, provided by superstring theory, in the more general noncommutative geometric context of M-Theory following the Connes- Douglas-Schwarz article., Comment: 17 pages, Latex, contains an important paragraph in section 2 which gives a better understanding

Foliated manifolds are particular examples of noncommutative spaces. In this article we try to give a qualitative description of the Godbillon-Vey class and its relation on the one hand to the holonomy and on the other hand to the topological entropy of a foliation, using a remarkable theorem proved recently by G. Duminy relating these three notions in the case of codim-1 foliations. Moreover we shall investigate its possible relation with the black hole entropy adopting the superstring theory origin of the black hole entropy in the extremal case. This situation we believe has some striking similarities with the explanation due to Bellissard of the integrality of the Hall conductivity in the quantum Hall effect. Our starting point is the Connes-Douglas-Schwarz article on compactifications of matrix models to noncommutative tori., Comment: 38 pages, TeX

We try to give a qualitative description of the Godbillon-Vey class and its relation on the one hand to the holonomy and on the other hand to the topological entropy of a foliation, using a remarkable theorem proved recently by G. Duminy (which still remains unpublished), relating these three notions in the case of codim-1 foliations. Moreover we shall investigate its possible consequences on string theory. In particular we shall present a conceptual argument according to which the curvature of the B-field (rank two antisymmetric tensor) of open strings might be related to the Godbillon-Vey class using a suitable generalisation of ``Non-Abelian Geometry'' which has just appeared in physics literature. Our starting point again is the Connes-Douglas-Schwarz article on compactifications of matrix models to noncommutative tori., Comment: 39 pages, TeX

We apply the Godbillon-Vey class to compute the transition amplitudes between some non-commutative solitons in M-Theory; our context is that of Connes-Douglas-Schwarz where they considered compactifications of matrix models on noncommutative tori. Two important consequences follow: we describe a new normalisation for the Abelian Chern-Simons theory using symplectic 4-manifolds as providing cobordisms for tight contact 3-manifolds and we construct a new(?) invariant for 3-manifolds. Moreover we modify the topological Lagrangian density suggested for M-Theory in a previous article to a \textsl{quadratic} one using the fact that the \emph{functor of immersions is a linearisation (or ``the differential'') of the functor of embeddings}, Comment: 50 pages, TeX, extended version

We introduce a Lagrangian density for M-Theory which is purely topological using Gelfand-Fuchs cohomology. Next we calculate the partition function which indeed gives topological invariants that can be expressed via the Ray-Singer analytic torsion., Comment: new extended version

We introduce a new invariant for foliations using the even pairing between K-homology and cyclic homology and discuss some possible applications in physics., Comment: 45 pages, extended version. to appear in Commun. Math. Phys., communicated with A. Connes

We use the homological algebra context to give a more rigorous proof of Polyakov's basic variational formula for loop spaces., Comment: Latex, 17 pages, no figures