Schroedinger's Cat is not Alone

We introduce the `Complete Wave Function' and deduce that all living beings, not just Schroedinger's cat, are actually described by a superposition of `alive' and `dead' quantum states; otherwise they would never die. Therefore this proposal provides a quantum mechanical explanation to the world-wide observation that we all pass away. Next we consider the Measurement problem in the framework of M-theory. For this purpose, together with Schroedinger's cat we also place inside the box Rasputin's cat, which is unaffected by poison. We analyse the system identifying its excitations (catons and catinos) and we discuss its evolution: either to a classical fight or to a quantum entanglement. We also propose the $BSV\Psi$ scenario, which implements the Complete Wave Function as well as the Big Bang and the String Landscape in a very (super)natural way. Then we test the gravitational decoherence of the entangled system applying an experimental setting due to Galileo. We also discuss the Information Loss paradox. For this purpose we consider a massless black cat falling inside a massive black hole. After that we outline a method to compute the contribution of black cats to the dark matter of the universe. Finally, in the spirit of Schroedinger, we propose that next generation double-slit experiments should use cats as projectiles. Cat interferometry will inevitably lead to the `Many Cats' interpretation of Quantum Mechanics, allowing to shed new light on old mysteries and paradoxes. For example, according to this interpretation, conservative estimates show that decision making of a single domestic cat will create about 550 billion whole universes every day, with as many replicas of itself.Comment: Prepared for April Fools' Day. Latex, 12 page

Isomorphism classes for quantum Heisenberg manifolds

We embed the quantum Heisenberg manifold in a crossed product algebra. This enables us to show that, in the irrational case, all tracial states on \dc induce the same homomorphism on the K_0-group. We conclude that two irrational quantum Heisenberg manifolds \dc and $D^c_{\mu ' \nu '}$ are isomorphic if and only if the parameters $(\mu,\nu)$ and $(\mu ',\nu ')$ belong to the same orbit under the usual action of GL_2(\ZZ) on the torus.Comment: LaTeX, 15 page

"Vector bundles" over quantum Heisenberg manifolds

By means of techniques from the Morita equivalence theory, we get finitely generated and projective modules over the quantum Heisenberg manifolds. This enables us to get some information about the range of the trace of these algebras, at the level of the K_{0}-group, in terms of the Poisson bracket in whose direction the manifolds are deformed.Comment: 10 pages, LaTeX format, BA-93-0

A study of galaxies near low-redshift quasars

The impact of quasars on their galaxy neighbors is an important factor in the understanding of the galaxy evolution models. The aim of this work is to characterize the close environments of quasars at low redshift (z$<$0.2) with the most statistically complete sample up to date using the seventh data release of the Sloan Digital Sky Survey. We have used 305 quasar-galaxy associations with spectroscopically measured redshifts within the projected distance range of 350 kpc, to calculate how surface densities of galaxies, colors, star-formation rates, oxygen abundances, dust extinction and ionization changes as a function of the distance to the quasars. We also identify and exclude the AGN from our main galaxy sample and calculate surface density of different galaxy types. We have done this in three different quasar-galaxy redshift difference ranges $|\Delta$z$|<$ 0.001, 0.006, and 0.012. Our results suggest that there is a significant increase of the galaxy surface density around quasars, indicating quasar formation by merging scenario. We also observe a gap in the surface densities of AGN and blue galaxies at a distance of approximately 150 kpc from the quasar. We see no significant changes of star formation rate, color and ionization as function of distance from the quasar. From this investigation we cannot see any effects from quasars on their galaxy companions.Comment: Master thesis in astronomy; quasars; galaxies; environments; SDS

Takai Duality for Crossed Products by Hilbert C*-bimodules

We discuss the crossed product by the dual action of the circle on the crossed product of a C*-algebra A by a Hilbert C*-bimodule X. When X is an A-A Morita equivalence bimodule, the double crossed product is shown to be Morita equivalent to the C*-algebra A.Comment: 16 page

Generalized fixed-point algebras of certain actions on crossed products

Let G and H be two locally compact groups acting on a C*-algebra A by commuting actions. We construct an action on the crossed product AXG out of a unitary 2-cocycle u and the action of H on A. For A commutative, and free and proper actions of G and H, we show that if the roles of these two actions are reversed, and u is replaced by u*, then the corresponding generalized fixed-point algebras, in the sense of Rieffel, are strong-Morita equivalent. We apply this result to the computation of the K-theory of quantum Heisenberg manifolds.Comment: 23 pages, LaTeX format, BA-93-0

Morita Equivalence for Quantum Heisenberg Manifolds

We discuss Morita equivalence within the family of quantum Heisenberg manifolds. The main tool employed is the generalization of a result of P. Green and M. Rieffel about Morita equivalence of transformation groups to crossed products by Hilbert bimodules.Comment: 9 pages, to appear in the Proceedings of the AM

Remarks on Global Anomalies in DHS Orientifolds

I review the main features of the Dijkstra-Huiszoon-Schellekens (DHS) orientifolds and report on the search for global anomalies that Schellekens and the author have performed for these models.Comment: Invited talk given at the Strings 2006 Workshop, Shanghai (China), June 2006, 6 page

Brane Worlds, the Subanthropic Principle and the Undetectability Conjecture

In the recent article `Conflict between anthropic reasoning and observation'(gr-qc/0303070) Ken D. Olum, using some inflation-based ideas and the anthropic premise that we should be typical among all intelligent observers in the Universe, arrives at the puzzling conclusion that `we should find ourselves in a large civilization (of galactic size) where most observers should be, while in fact we do not'. In this note we discuss the intriguing possibility whether we could be in fact immersed in a large civilization without being aware of it. Our conclusion is that this possibility cannot be ruled out provided two conditions are met, that we call the Subanthropic Principle and the Undetectability Conjecture. ----- En el reciente articulo `Conflicto entre razonamiento antropico y observacion' Ken D. Olum, basandose en algunas ideas sobre la inflacion cosmologica y en la premisa antropica de que tenemos que ser tipicos entre los observadores inteligentes del Universo, llega a la sorprendente conclusion de que `deberiamos encontrarnos en una civilizacion grande (de tamanio galactico) al igual que la mayoria de los observadores, mientras que de hecho no lo estamos'. En este articulo discutimos la posibilidad de que nuestra civilizacion este de hecho inmersa en una civilizacion grande, sin que seamos conscientes de ello. Nuestra conclusion es que esta posibilidad no puede descartarse si se cumplen dos condiciones, que llamamos el Principio Subantropico y la Conjetura de Indetectabilidad.Comment: Dedicated to Giordano Bruno, Latex, 15 pages. Four new footnotes, one last paragraph in the Appendix and several minor improvements in the redaction. Spanish version also availabl

Recent Results on N=2 Superconformal Algebras

In the last six years remarkable developments have taken place concerning the representation theory of N=2 superconformal algebras. Here we present the highlights of such developments.Comment: Latex, 11 pages. Invited talk presented at the International Conference on Conformal Field Theory and Integrable Models, Landau Institute, Moscow (Russia), June 1999, and at the 6th International Wigner Symposium, Bogazici University, Istambul (Turkey), August 199