Results for "Yaé Ulrich Gaba"

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A new characterization of partial metric completenessFeb 08 2019In this article, we present a new characterization of the completeness of a partial metric space--which we call \textit{orbital characterization}-- using fixed point results.
Partial quasi-metric completeness via Kannan-type fixed pointsFeb 08 2019In this short note, we obtain partial quasi-metric versions of Kannan's fixed point theorem for self-mappings. Moreover, we use these fixed points results to characterize a certain type of completeness in partial quasi-metric spaces. We have reported ... More
Chatterjea type fixed point in Partial $b$-metric spacesFeb 08 2019In this paper, we give and prove two Chatterjea type fixed point theorems on partial $b$-metric space. We propose an extension to the Banach contraction principle on partial $b$-metric space which was already presented by Shukla and also study some related ... More
$(C_α,C_β)$-admissible functions in quasi-pseudometric type spacesMay 15 2015In this article, we give some fixed point results in left $K$-complete quasi-pseudometric type spaces for self-mappings that are $(C_\alpha,C_\beta)$-admissible.
An order theoretic approach in fixed point theoryNov 07 2014In the present article, we show the existence of a coupled fixed point for an order preserving mapping in a preordered left K-complete quasi-pseudometric space using a preorder induced by an appropriate function. We also define the concept of left-weakly ... More
Advances in Startpoint Theory for quasi-pseudometric spacesDec 05 2014This paper presents some startpoint (endpoint, fixed point) theorems for mutli-valued maps that generalize recent results proved by Y. U. Gaba \cite{rico, ricoo}.
Startpoints and $(α,γ)$-Contractions in Quasi-Pseudometric SpacesAug 22 2014We introduce the concept of $\it{ startpoint}$ and $\it{endpoint}$ for multivalued maps defined on a quasi-pseudometric space. We investigate the relation between these new concepts and the existence of fixed points for these set valued maps.
Fixed points for weak contractions in metric type spacesDec 01 2014May 10 2015In this article, we prove some fixed point theorems in metric type spaces. This article is just a generalization some results previously proved in \cite{niyi-gaba}. In particular, we give some coupled common fixed points theorems under weak contractions. ... More
Common Coupled Fixed Point Theorems for Maps in a $T_0$-ultra-quasi-metric SpaceDec 03 2014In this article, we prove the existence of common fixed points for a pair of maps on a $q$-spherically complete $T_0$-ultra-quasi-metric space. The present article is a generalization, in the assymmetric setting of the paper of Rao et al.\cite{Rao}. The ... More
Starbursts versus Truncated Star Formation in Nearby Clusters of GalaxiesNov 07 2000We present long-slit spectroscopy, B and R bandpass imaging, and 21 cm observations of a sample of early-type galaxies in nearby clusters which are known to be either in a star-forming phase or to have had star formation which recently terminated. From ... More
Neutrino Interactions with Nucleons and Nuclei: Importance for Long-Baseline ExperimentsFeb 01 2016Mar 19 2016This article reviews our present knowledge of neutrino interactions with nucleons. It then discusses the interactions with nuclei, the target material of all presently running and planned long-baseline experiments. Particular emphasis is placed on descriptions ... More
The universal eta-invariant for manifolds with boundaryMar 09 2014Oct 23 2014We extend the theory of the universal eta-invariant to the case of relative bordism groups of manifolds with boundaries. This allows the construction of secondary descendants of the universal eta-invariant. We obtain an interpretation of Laures' f-invariant ... More
Quantum corrected model for plasmonic nanoparticles: A boundary element method implementationMay 13 2015We present a variant of the recently developed quantum corrected model (QCM) for plasmonic nanoparticles [Nature Commun. 3, 825 (2012)] using non-local boundary conditions. The QCM accounts for electron tunneling in narrow gap regions of coupled metallic ... More
Neutrino Interactions and Long Baseline PhysicsApr 30 2015This is a very short review of neutrino-nucleus interactions and their influence on the analysis of long-baseline experiments.
Membrane Instantons from Toda Field TheoryAug 20 2014Sep 01 2014Four-dimensional quaternion-Kaehler metrics with an isometry are determined by solutions to the SU($\infty$) Toda equation. We set up a perturbation theory to construct approximate solutions to the latter which can be interpreted as membrane instanton ... More
Flavour and CP ViolationApr 13 2013In this talk I review the status of B mixing in the Standard Model and the room for new physics in B_s and B_d mixing in the light of recent LHCb data.
Spectral Statistics and Dynamical Localization: sharp transition in a generalized Sinai billiardJul 12 1999We consider a Sinai billiard where the usual hard disk scatterer is replaced by a repulsive potential with $V(r)\sim\lambda r^{-\alpha}$ close to the origin. Using periodic orbit theory and numerical evidence we show that its spectral statistics tends ... More
Ab-initio calculation of optical absorption in semiconductors: A density-matrix descriptionAug 21 2001We show how to describe Coulomb renormalization effects and dielectric screening in semiconductors and semiconductor nanostructures within a first-principles density-matrix description. Those dynamic variables and approximation schemes which are required ... More
Anti-B --> X(s) gamma: Standard Model and BeyondMay 14 2008Jul 13 2008We present a concise review of the recent theoretical progress concerning the standard model calculation of the inclusive radiative anti-B --> X(s) gamma decay. Particular attention is thereby devoted to the calculations of the next-to-next-to-leading ... More
How To Kill a PenguinJun 23 2007Within constrained minimal-flavor-violation the large destructive flavor-changing Z-penguin managed to survive eradication so far. We give a incisive description of how to kill it using the precision measurements of the Z -> b anti-b pseudo observables. ... More
Review on new physics in heavy flavors: B-meson sectorMar 24 2013Nov 26 2013A brief review of theoretical aspects of new-physics searches in flavor physics is given. Special attention is thereby devoted to B_s mixing and the interplay of high- and low-p_T observations.
Recent Developments in Bbar -> X_s gammaJun 14 2007Jun 23 2007We present a concise review of the recent theoretical progress concerning the standard model calculation of the inclusive radiative Bbar -> X_s gamma decay. Particular attention is thereby devoted to the calculations of the next-to-next-to-leading order ... More
Theoretical Status of K->pinunubar DecaysMay 15 2006We present a concise review of the theoretical status of rare K->pinunubar decays in and beyond the standard model. Particular attention is thereby devoted to the recent calculation of the next-to-next-to-leading order corrections to the charm quark contribution ... More
The Quantum Mechanics of Being and Its ManifestationApr 04 2016How can quantum mechanics be (i) the fundamental theoretical framework of contemporary physics and (ii) a probability calculus that presupposes the events to which, and on the basis of which, it assigns probabilities? The question is answered without ... More
The Pondicherry interpretation of quantum mechanics: An overviewDec 23 2004Feb 24 2005An overview of the Pondicherry interpretation of quantum mechanics is presented. This interpretation proceeds from the recognition that the fundamental theoretical framework of physics is a probability algorithm, which serves to describe an objective ... More
Why the laws of physics are just soFeb 26 2002Does a world that contains chemistry entail the validity of both the standard model of elementary particle physics and general relativity, at least as effective theories? This article shows that the answer may very well be affirmative. It further suggests ... More
Making sense of a world of clicksFeb 26 2002In a recent article O. Ulfbeck and A. Bohr (Foundations of Physics 31, 757, 2001) have stressed the genuine fortuitousness of detector clicks, which has also been pointed out, in different terms, by the present author (American Journal of Physics 68, ... More
Two theories of decoherenceAug 01 2001Theories of decoherence come in two flavors---Platonic and Aristotelian. Platonists grant ontological primacy to the concepts and mathematical symbols by which we describe or comprehend the physical world. Aristotelians grant it to the physical world. ... More
Quantum Nonlocality ExplainedNov 05 2014Feb 11 2015Quantum theory's violation of remote outcome independence is assessed in the context of a novel interpretation of the theory, in which the unavoidable distinction between the classical and quantum domains is understood as a distinction between the manifested ... More
Quantum mechanics explainedJul 02 2006Jul 14 2006The physical motivation for the mathematical formalism of quantum mechanics is made clear and compelling by starting from an obvious fact - essentially, the stability of matter - and inquiring into its preconditions: what does it take to make this fact ... More
A space for the quantum worldJul 02 2001Epistemic interpretations of quantum mechanics fail to address the puzzle posed by the occurrence of probabilities in a fundamental physical theory. This is a puzzle about the physical world, not a puzzle about our relation to the physical world. Its ... More
The world according to quantum mechanics (or, the 18 errors of Henry P. Stapp)May 21 2001Several errors in Stapp's interpretation of quantum mechanics and its application to mental causation (Henry P. Stapp, "Quantum theory and the role of mind in nature," e-Print quant-ph/0103043) are pointed out. An interpretation of (standard) QM that ... More
Electromagnetic Waves in Variable MediaApr 09 2011Jul 16 2012Two methods are explained to exactly solve Maxwell's equations where permittivity, permeability and conductivity may vary in space. In the constitutive relations, retardation is regarded. If the material properties depend but on one coordinate, general ... More
Diffraction of Electromagnetic WavesNov 18 2009Feb 02 2010The general method to obtain solutions of the Maxwellian equations from scalar representatives is developed and applied to the diffraction of electromagnetic waves. Kirchhoff's integral is modified to provide explicit expressions for these representatives. ... More
Twisted K-theory and obstructions against positive scalar curvature metricsAug 18 2011Jun 17 2013We decompose the twisted index obstruction $\theta(M)$ against positive scalar curvature metrics for oriented manifolds with spin universal cover into a pairing of a twisted $K$-homology with a twisted $K$-theory class and prove that $\theta(M)$ does ... More
On Dynamic Breadth-First Search in External-MemoryFeb 20 2008We provide the first non-trivial result on dynamic breadth-first search (BFS) in external-memory: For general sparse undirected graphs of initially $n$ nodes and O(n) edges and monotone update sequences of either $\Theta(n)$ edge insertions or $\Theta(n)$ ... More
Projective quantum spacesOct 06 1994Associated to the standard $SU_{q}(n)$ R-matrices, we introduce quantum spheres $S_{q}^{2n-1}$, projective quantum spaces $CP_{q}^{n-1}$, and quantum Grassmann manifolds $G_{k}(C_{q}^{n})$. These algebras are shown to be homogeneous quantum spaces of ... More
Constraints on Neutralino masses and mixings from Cosmology and Collider PhysicsJul 11 2007Aug 09 2007Bounds on cross section measurements of chargino pair production at LEP yield a bound on the chargino mass. If the GUT relation is assumed, the lightest neutralino must be heavier than $\approx 45 -50\GeV$. If no GUT relation is assumed, no lower bound ... More
Eine untere Massenschranke fuer Neutralinos aus Supernova-KuehlungJul 29 2004In my diploma thesis I calculate a lower mass bound of the lightest nutralino assuming an additional supernova cooling mechanism. I consider elektron-positron annihilation and nucleon-nucleon bremsstrahlung as cooling processes. These cooling processes ... More
Low-temperature conductance and DC current noise in a quantum wire with impurityApr 04 1996Apr 12 1996The nonlinear conductance for tunneling through an impurity in a Luttinger liquid and the nonequilibrium DC current noise are calculated exactly for low temperatures. We present a pedestrian pathway towards the exact solution which is based on analytic ... More
Non-linear numerical Schemes in General RelativityJan 25 2002This thesis describes the application of numerical techniques to solve Einstein's field equations in three distinct cases. First we present the first long-term stable second order convergent Cauchy characteristic matching code in cylindrical symmetry ... More
The density-matrix renormalization group in the age of matrix product statesAug 20 2010Jan 03 2011The density-matrix renormalization group method (DMRG) has established itself over the last decade as the leading method for the simulation of the statics and dynamics of one-dimensional strongly correlated quantum lattice systems. In the further development ... More
A problem of I. Raşa on Bernstein polynomials and convex functionsAug 27 2016We present an elementary proof of a conjecture by I. Ra\c{s}a which is an inequality involving Bernstein basis polynomials and convex functions. It was affirmed in positive very recently by the use of stochastic convex orderings. Moreover, we derive the ... More
A counter-example to Martino's conjecture about generic Calogero-Moser familiesJan 21 2013Sep 25 2013The Calogero-Moser families are partitions of the irreducible characters of a complex reflection group derived from the block structure of the corresponding restricted rational Cherednik algebra. It was conjectured by Martino in 2009 that the generic ... More
Mapping class groups of compression bodies and 3-manifoldsJul 18 2006Jul 16 2007We analyze the mapping class group of extendible automorphisms of the exterior boundary W of a compression body of dimension 3 or 4, which extend over the compression body (Q,V), where V is the interior boundary. Those that extend as automorphisms of ... More
Manin's conjecture for a quintic del Pezzo surface with A_2 singularityOct 08 2007Manin's conjecture is proved for a split del Pezzo surface of degree 5 with a singularity of type A_2.
Manin's conjecture for a certain singular cubic surfaceApr 01 2005We prove Manin's conjecture for a singular cubic surface S with a singularity of type E6. If U is the open subset of S obtained by deleting the unique line from S, then the number of rational points in U with anticanonical height bounded by B behaves ... More
An identity for derivativesJun 24 2016We present a generalization of a formula of higher order derivatives and give a short proof.
A Sobolev Poincaré type inequality for integral varifoldsAug 27 2008May 25 2009In this work a local inequality is provided which bounds the distance of an integral varifold from a multivalued plane (height) by its tilt and mean curvature. The bounds obtained for the exponents of the Lebesgue spaces involved are shown to be sharp. ... More
On the regularity of special difference divisorsSep 06 2012In this note we prove that the difference divisors associated with special cycles on unitary Rapoport-Zink spaces of signature (1,n-1) in the unramified case are always regular.
Derivations with Quantum Group ActionMay 11 2000The derivations of a left coideal subalgebra B of a Hopf algebra A which are compatible with the comultiplication of A (that is, the covariant first order differential calculi, as defined by Woronowicz, on a quantum homogeneous space) are related to certain ... More
The Little Bang: Searching for quark-gluon matter in relativistic heavy-ion collisionsSep 14 2000Sep 19 2000I review the status of the search for quark-gluon plasma in relativistic heavy-ion collisions. The available data provide strong evidence for the "three pillars of the Little Bang model": strong radial expansion of the collision fireball with Hubble-like ... More
Some Applications of the Isoperimetric Inequality for Integral VarifoldsAug 27 2008In this work the Isoperimetric Inequality for integral varifolds is used to obtain sharp estimates for the size of the set where the density quotient is small and to generalise Calder\'on's and Zygmund's theory of first order differentiability for functions ... More
Nielsen coincidence theory in arbitrary codimensionsAug 03 2004Given two maps f_1, f_2 : M^m \longrightarrow N^n between manifolds of the indicated arbitrary dimensions, when can they be deformed away from one another? More generally: what is the minimum number MCC (f_1, f_2) of pathcomponents of the coincidence ... More
Counting integral points on universal torsorsOct 22 2008Feb 13 2009Manin's conjecture for the asymptotic behavior of the number of rational points of bounded height on del Pezzo surfaces can be approached through universal torsors. We prove several auxiliary results for the estimation of the number of integral points ... More
Optimal quantum gates for semiconductor qubitsJan 15 2007We employ optimal control theory to design optimized quantum gates for solid-state qubits subject to decoherence. At the example of a gate-controlled semiconductor quantum dot molecule we demonstrate that decoherence due to phonon couplings can be strongly ... More
Quantum Mechanics and ExperienceOct 22 2014Jun 27 2016After a summary of Bohr's views and their relation to Kant's theory of science, two fruitless lines of attack on the measurement problem are discussed: the way of the psi-ontologist and the way of the QBist. In the remainder of the paper the following ... More
Comment on "Quantum Physics from A to Z"Aug 29 2005This is a comment on a collection of statements gathered on the occasion of the Quantum Physics of Nature meeting in Vienna.
Do quantum states evolve? Apropos of Marchildon's remarksJul 17 2003Marchildon's (favorable) assessment (quant-ph/0303170, to appear in Found. Phys.) of the Pondicherry interpretation of quantum mechanics raises several issues, which are addressed. Proceeding from the assumption that quantum mechanics is fundamentally ... More
Quantum Mechanics and the Cookie Cutter ParadigmSep 01 2000Sep 02 2000What has so far prevented us from decrypting quantum mechanics is the Cookie Cutter Paradigm, according to which the world's synchronic multiplicity derives from surfaces that carve up space in the manner of three-dimensional cookie cutters. This insidious ... More
Quantum mechanics and elements of realityApr 26 1999It is widely accepted that a Born probability of 1 is sufficient for the existence of a corresponding element of reality. Recently Vaidman has extended this idea to the ABL probabilities of the time-symmetrized version of quantum mechanics originated ... More
The Pondicherry interpretation of quantum mechanicsMar 15 1999Mar 04 2000This article presents a novel interpretation of quantum mechanics. It extends the meaning of ``measurement'' to include all property-indicating facts. Intrinsically space is undifferentiated: there are no points on which a world of locally instantiated ... More
CV and LMXB Population SynthesisAug 20 1997I discuss population synthesis methods in the context of low-mass compact binaries. Two examples, both constraining the largely unknown strength of orbital angular momentum losses, illustrate the power and problems of such studies. For CVs, the ``standard'' ... More
On rational injectivity of Kasparovs assembly map in dimension <=2Oct 08 2012The author presents a new proof of injectivity of the composition of the inverse of the rational Chern Character in homology applied to the classifying space BG of a (countable) discrete group G, restricted to dimensions less or equal than two, with the ... More
The numerical relativity breakthrough for binary black holesNov 14 2014The evolution of black-hole binaries in vacuum spacetimes constitutes the two-body problem in general relativity. The solution of this problem in the framework of the Einstein field equations is a substantially more complex exercise than that of the dynamics ... More
Numerical relativity in higher dimensionsJan 16 2013Jan 17 2013We present an overview of recent developments in numerical relativity studies of higher dimensional spacetimes with a focus on time evolutions of black-hole systems. After a brief review of the numerical techniques employed for these studies, we summarize ... More
Binary black-hole evolutions of excision and puncture dataJun 19 2006Oct 16 2007We present a new numerical code developed for the evolution of binary black-hole spacetimes using different initial data and evolution techniques. The code is demonstrated to produce state-of-the-art simulations of orbiting and inspiralling black-hole ... More
Extreme exchangeable random order processes by positive definite functions on semigroupsJan 02 2004Jul 04 2005Based on previous work of Paul Ressel and myself, I show that the space of all "continuous" exchangeable probability measures on a certain set of order processes is a Bauer simplex.
From coinductive proofs to exact real arithmetic: theory and applicationsJan 11 2011Apr 23 2012Based on a new coinductive characterization of continuous functions we extract certified programs for exact real number computation from constructive proofs. The extracted programs construct and combine exact real number algorithms with respect to the ... More
Measurements of Top Properties at the TevatronJun 13 2007The large data samples of thousands of top events collected at the Tevatron experiments CDF and D0 allow for a variety of measurements to analyze the properties of the top quark. Guided by the question "Is the top quark observed at the Tevatron really ... More
Searches for High Mass Resonances and Exotics at the TevatronFeb 05 2012I review recent searches for physics beyond the standard model from the CDF and D0 experiments at the Fermilab Tevatron collider, covering searches for fourth generation quarks, exotic resonances, universal extra dimensions, and dark matter particles. ... More
Light emission from particle beam induced plasma - An overviewNov 26 2015Experiments to study the light emission from plasma produced by particle beams are presented. Fundamental aspects in comparison with discharge plasma formation are discussed. It is shown that the formation of excimer molecules is an important process. ... More
Comment on: Investigation of the thermal lens effect of the TGG crystal in high-power frequency-doubled laser with single frequency operationAug 25 2015In their article, the authors of [Opt. Express 23, 4981 (2015)] observe step-like behavior and hysteresis of the output power of a diode-end-pumped Nd:YVO 4-laser as a function of pump power. While claiming that this behavior is a proof of thermal lensing ... More
Particle Interferometry in Heavy-Ion CollisionsJan 27 1997By measuring hadronic single-particle spectra and two-particle correlations in heavy-ion collisions, the size and dynamical state of the collision fireball at freeze-out can be reconstructed. I discuss the relevant theoretical methods and their limitations. ... More
Hanbury-Brown/Twiss Interferometry for Relativistic Heavy-Ion Collisions: Theoretical AspectsSep 11 1996I discuss two-particle intensity interferometry as a method to extract from measured 1- and 2-particle momentum spectra information on the space-time geometry and dynamics of the particle emitting source. Particular attention is given to the rapid expansion ... More
TFT98: Proceedings of the 5th International Workshop on Thermal Field Theories and Their ApplicationsNov 25 1998Mar 24 1999This contains the Proceedings of the 5th International Workshop on Thermal Field Theories and Their Applications (TFT98) which took place on 10-14 August 1998 in Regensburg, Germany. The contents are in html and postscript format. The html files contain ... More
Mackey functors and abelian class field theoriesNov 03 2011Motivated by the work of J\"urgen Neukirch and Ivan Fesenko we propose a general definition of an abelian class field theory from a purely group-theoretical and functorial point of view. This definition allows a modeling of abelian extensions of a field ... More
Coincidence theory in arbitrary codimensions: the minimizing problemJun 01 2006Coincidences of maps between smooth manifolds are studied via a geometric approach which involves (nonstabilized) normal bordism theory and pathspaces.
Geometric and homotopy theoretic methods in Nielsen coincidence theoryJun 01 2006In classical fixed point and coincidence theory the notion of Nielsen numbers has proved to be extremely fruitful. Here we extend it to pairs (f_1, f_2) of maps between manifolds of arbitrary dimensions. This leads to estimates of the minimum numbers ... More
Minimizing coincidence numbers of maps into projective spacesJun 01 2006Apr 12 2009In this paper we continue to study (`strong') Nielsen coincidence numbers (which were introduced recently for pairs of maps between manifolds of arbitrary dimensions) and the corresponding minimum numbers of coincidence points and pathcomponents. We explore ... More
Linking and coincidence invariantsAug 03 2004Given a link map f into a manifold of the form Q = N \times \Bbb R, when can it be deformed to an unlinked position (in some sense, e.g. where its components map to disjoint \Bbb R-levels) ? Using the language of normal bordism theory as well as the path ... More
Universal torsors of Del Pezzo surfaces and homogeneous spacesApr 10 2006Feb 07 2007Let Cox(S) be the homogeneous coordinate ring of the blow-up S of P^2 in r general points, i.e., a smooth Del Pezzo surface of degree 9-r. We prove that for r=6 and 7, Proj(Cox(S)) can be embedded into G/P, where G is an algebraic group with root system ... More
Relaxation, New Combinatorial and Polynomial Algorithms for the Linear Feasibility ProblemJun 12 2002We consider the homogenized linear feasibility problem, to find an $x$ on the unit sphere, satisfying $n$ line ar inequalities $a_i^Tx\ge 0$. To solve this problem we consider the centers of the insphere of spherical simpl ices, whose facets are determined ... More
A note on injective envelopes and von Neumann algebrasOct 14 2013Jan 06 2014The article exhibits certain relations between the injective envelope I(A) of a C*-algebra A and the von Neumann algebra generated by a representation lambda of A provided it is injective. More specifically we show that there exist positive retractions ... More
The Dirichlet problem and spectral theory of operator algebrasJan 06 2014May 13 2014The main result of the paper is an extension of the Dirichlet problem from (closures of) bounded open domains U to arbitrary compact subsets X of the complex plane, i.e. the closure of the corresponding space of functions which are harmonic in a neighbourhood ... More
On extendibility and decomposability of certain *-linear maps into C (X)Jul 23 2013We consider *-linear maps into a commutative C*-algebra C (X) of continuous functions on a locally compact Hausdorff space X with certain specified properties and prove two results: (1) an extension result for a class of *-linear maps Y --> C (X) which ... More
Massive creation of entangled exciton states in semiconductor quantum dotsNov 05 2002An intense laser pulse propagating in a medium of inhomogeneously broadened quantum dots massively creates entangled exciton states. After passage of the pulse all single-exciton states remain unpopulated (self-induced transparency) whereas biexciton ... More
Market Implied Probability Distributions and Bayesian Skew EstimationNov 04 2009We review and illustrate how the volatility smile translates into a probability distribution, the market-implied probability distribution representing believes priced in. The effects of changes in the smile are examined. Special attention is given to ... More
Rare K -> pi nu nubar DecaysDec 01 2005We present a concise review of the theoretical status of rare K -> pi nu nubar decays in the standard model (SM). Particular attention is thereby devoted to the recent calculation of the next-to-next-to-leading order (NNLO) corrections to the charm quark ... More
Interpreting Bananaworld: A response to Bub's Quantum Mechanics for PrimatesDec 16 2012The interpretative principle proposed by Bub in 1211.3062v1 [quant-ph] is justified only for all practical purposes (Bell's "FAPP trap"). An alternative interpretative principle is proposed. It brings to light those features of the quantum world because ... More
Is the end in sight for theoretical pseudophysics?May 17 2003Dec 27 2004The question of what ontological message (if any) is encoded in the formalism of contemporary physics is, to say the least, controversial. The reasons for this state of affairs are psychological and neurobiological. The processes by which the visual world ... More
The One, the Many, and the QuantumMay 26 2000The problem of understanding quantum mechanics is in large measure the problem of finding appropriate ways of thinking about the spatial and temporal aspects of the physical world. The standard, substantival, set-theoretic conception of space is inconsistent ... More
Why the wave function, of all things?Nov 05 2014There are reasons to doubt that making sense of the wave function (other than as a probability algorithm) will help with the project of making sense of quantum mechanics. The consistency of the quantum-mechanical correlation laws with the existence of ... More
QBism: A Critical AppraisalSep 11 2014By insisting that the formal apparatus of quantum mechanics is a probability calculus, QBism opens the door to a deeper understanding of what quantum mechanics is trying to tell us. By insisting on a subjectivist Bayesian interpretation of probability ... More
Objective probability and quantum fuzzinessMar 05 2007Feb 04 2009This paper offers a critique of the Bayesian interpretation of quantum mechanics with particular focus on a paper by Caves, Fuchs, and Schack containing a critique of the "objective preparations view" or OPV. It also aims to carry the discussion beyond ... More
Reflections on the Spatiotemporal Aspects of the Quantum WorldMay 11 2002The proper resolution of the so-called measurement problem requires a "top-down" conception of the quantum world that is opposed to the usual "bottom-up" conception, which builds on an intrinsically and maximally differentiated manifold. The key to that ... More
Quantum mechanics and consciousness: fact and fictionFeb 09 2001Aug 03 2014This article was written in response to a request from an editor of American Vedantist. It is shown that the idea that consciousness is essential to understanding quantum mechanics arises from logical fallacies. This may be welcome news to those who share ... More
String structures and trivialisations of a Pfaffian line bundleSep 04 2009Apr 15 2011The present paper is a contribution to categorial index theory. Its main result is the calculation of the Pfaffian line bundle of a certain family of real Dirac operators as an object in the category of line bundles. Furthermore, it is shown how string ... More
Orbifold index and equivariant K-homologyJan 26 2007Feb 27 2007We consider a invariant Dirac operator D on a manifold with a proper and cocompact action of a discrete group G. It gives rise to an equivariant K-homology class [D]. We show how the index of the induced orbifold Dirac operator can be calculated from ... More
Topological flatness of local models in the ramified caseMay 06 2002Jun 04 2003Local models are schemes defined in terms of linear algebra which can be used to study the local structure of integral models of certain Shimura varieties, with parahoric level structure. We investigate the local models for groups of the form Res_{F/\Q_p} ... More