Results for "John Lapinskas"

total 20703took 0.10s
Fine-grained reductions from approximate counting to decisionJul 14 2017Feb 07 2019In this paper, we introduce a general framework for fine-grained reductions of approximate counting problems to their decision versions. (Thus we use an oracle that decides whether any witness exists to multiplicatively approximate the number of witnesses ... More
Phase Transitions of the Moran Process and Algorithmic ConsequencesApr 06 2018Aug 15 2018The Moran process is a random process that models the spread of genetic mutations through graphs. If the graph is connected, the process eventually reaches "fixation", where every vertex is a mutant, or "extinction", where no vertex is a mutant. Our main ... More
Optimal packings of Hamilton cycles in graphs of high minimum degreeNov 14 2012We study the number of edge-disjoint Hamilton cycles one can guarantee in a sufficiently large graph G on n vertices with minimum degree d = (1/2+a)n. For any constant a > 0, we give an optimal answer in the following sense: let reg_even(n,d) denote the ... More
Approximately counting locally-optimal structuresNov 25 2014Apr 18 2016A locally-optimal structure is a combinatorial structure such as a maximal independent set that cannot be improved by certain (greedy) local moves, even though it may not be globally optimal. It is trivial to construct an independent set in a graph. It ... More
Approximately counting and sampling small witnesses using a colourful decision oracleJul 10 2019In this paper, we prove "black box" results for turning algorithms which decide whether or not a witness exists into algorithms to approximately count the number of witnesses, or to sample from the set of witnesses approximately uniformly, with essentially ... More
On-line Ramsey numbers of paths and cyclesApr 15 2014Oct 20 2014Consider a game played on the edge set of the infinite clique by two players, Builder and Painter. In each round, Builder chooses an edge and Painter colours it red or blue. Builder wins by creating either a red copy of $G$ or a blue copy of $H$ for some ... More
Optimal covers with Hamilton cycles in random graphsMar 17 2012Jul 24 2013A packing of a graph G with Hamilton cycles is a set of edge-disjoint Hamilton cycles in G. Such packings have been studied intensively and recent results imply that a largest packing of Hamilton cycles in G_n,p a.a.s. has size \lfloor delta(G_n,p) /2 ... More
Proof of a conjecture of Thomassen on Hamilton cycles in highly connected tournamentsMar 18 2013A conjecture of Thomassen from 1982 states that for every k there is an f(k) so that every strongly f(k)-connected tournament contains k edge-disjoint Hamilton cycles. A classical theorem of Camion, that every strongly connected tournament contains a ... More
Asymptotically Optimal Amplifiers for the Moran ProcessNov 13 2016We study the Moran process as adapted by Lieberman, Hauert and Nowak. A family of directed graphs is said to be strongly amplifying if the extinction probability tends to 0 when the Moran process is run on graphs in this family. The most-amplifying known ... More
Asymptotically Optimal Amplifiers for the Moran ProcessNov 13 2016Dec 05 2017We study the Moran process as adapted by Lieberman, Hauert and Nowak. This is a model of an evolving population on a graph where certain individuals, called "mutants" have fitness r and other individuals, called "non-mutants" have fitness 1. We focus ... More
Amplifiers for the Moran ProcessDec 17 2015May 05 2016The Moran process, as studied by Lieberman, Hauert and Nowak, is a randomised algorithm modelling the spread of genetic mutations in populations. The algorithm runs on an underlying graph where individuals correspond to vertices. Initially, one vertex ... More
Asymptotically Optimal Amplifiers for the Moran ProcessNov 13 2016Nov 23 2016We study the Moran process as adapted by Lieberman, Hauert and Nowak. This is a model of an evolving population on a graph where certain individuals, called "mutants" have fitness r and other individuals, called "non-mutants" have fitness 1. We focus ... More
A Fixed-Parameter Perspective on #BISFeb 17 2017Oct 13 2017The problem of (approximately) counting the independent sets of a bipartite graph (#BIS) is the canonical approximate counting problem that is complete in the intermediate complexity class #RH\Pi_1. It is believed that #BIS does not have an efficient ... More
Asymptotically Optimal Amplifiers for the Moran ProcessNov 13 2016Aug 01 2018We study the Moran process as adapted by Lieberman, Hauert and Nowak. This is a model of an evolving population on a graph or digraph where certain individuals, called "mutants" have fitness r and other individuals, called non-mutants have fitness 1. ... More
A.model of cation ordering in A(B'_xB''_1-x)O_3 relaxorsOct 20 2000We have shown that the lattice-gas model with four repulsive pair interaction constants (corresponding to the four nearest coordination shells) on a simple cubic lattice is a sufficient model to describe the main types of cation ordering in relaxors. ... More
Optimal Bacon-Shor codesSep 04 2012We study the performance of Bacon-Shor codes, quantum subsystem codes which are well suited for applications to fault-tolerant quantum memory because the error syndrome can be extracted by performing two-qubit measurements. Assuming independent noise, ... More
Saddlepoint approximations for likelihood ratio like statistics with applications to permutation testsMar 14 2012We obtain two theorems extending the use of a saddlepoint approximation to multiparameter problems for likelihood ratio-like statistics which allow their use in permutation and rank tests and could be used in bootstrap approximations. In the first, we ... More
Adaptation of the visibility graph algorithm to find the time lag between hydrogeological time seriesFeb 03 2017Estimating the time lag between two hydrogeologic time series (e.g. precipitation and water levels in an aquifer) is of significance for a hydrogeologist-modeler. In this paper, we present a method to quantify such lags by adapting the visibility graph ... More
Fast Autocorrelated Context Models for Data CompressionMay 23 2013Jun 10 2013A method is presented to automatically generate context models of data by calculating the data's autocorrelation function. The largest values of the autocorrelation function occur at the offsets or lags in the bitstream which tend to be the most highly ... More
Stochastic Time-Series SpectroscopyApr 06 2015Spectroscopically measuring low levels of non-equilibrium phenomena (e.g. emission in the presence of a large thermal background) can be problematic due to an unfavorable signal-to-noise ratio. An approach is presented to use time-series spectroscopy ... More
Scaling conditional tail probability and quantile estimatorsMar 30 2011We present a novel procedure for scaling relatively high frequency tail probability and quantile estimates for the conditional distribution of returns.
Diffeomorphisms, Analytic Torsion and Noncommutative GeometryJul 30 1996We prove an index theorem concerning the pushforward of flat B-vector bundles, where B is an appropriate algebra. We construct the associated analytic torsion form T. If Z is a smooth closed aspherical manifold, we show that T gives invariants of the ... More
The Dynamic Replicon: adapting to a changing cellular environmentDec 22 2008Eukaryotic cells are often exposed to fluctuations in growth conditions as well as endogenous and exogenous stress-related agents. In addition, during development global patterns of gene transcription change dramatically, and these changes are associated ... More
Rotation Numbers and Instability SetsMar 24 2003Translation and rotation numbers have played an interesting and important role in the qualitative description of various dynamical systems. In this exposition we are especially interested in applications which lead to proofs of periodic motions in various ... More
Path integrals from classical momentum pathsFeb 29 2004May 26 2005The path integral formulation of quantum mechanics constructs the propagator by evaluating the action S for all classical paths in coordinate space. A corresponding momentum path integral may also be defined through Fourier transforms in the endpoints. ... More
Isospectral Flow and Liouville-Arnold Integration in Loop AlgebrasJun 25 1993A number of examples of Hamiltonian systems that are integrable by classical means are cast within the framework of isospectral flows in loop algebras. These include: the Neumann oscillator, the cubically nonlinear Schr\"odinger systems and the sine-Gordon ... More
Eclipsing Binaries in Open ClustersNov 21 2006Detached eclipsing binaries are very useful objects for calibrating theoretical stellar models and checking their predictions. Detached eclipsing binaries in open clusters are particularly important because of the additional constraints on their age and ... More
Logic considered funJul 14 2015This report describes the development and use of an online teaching tool giving students exercises in logical modelling, or \emph{formalisation} as it is called in the older literature. The original version of the site, `Logic for Fun', dates from 2001, ... More
The tangent complex and Hochschild cohomology of E_n-ringsApr 01 2011Aug 29 2013In this work, we study the deformation theory of $\cE_n$-rings and the $\cE_n$ analogue of the tangent complex, or topological Andr\'e-Quillen cohomology. We prove a generalization of a conjecture of Kontsevich, that there is a fiber sequence $A[n-1] ... More
Latest Results from Heavy Quark SimulationsDec 22 1994The status of b-bbar and c-cbar calculations, numerical and analytic, are reviewed. The extraction of alpha_s and quark masses from spectrum calculations is discussed. The NRQCD and Improved Heavy Wilson formulations of heavy quarks are compared, and ... More
Moving NRQCDOct 16 1997I discuss the derivation and applications of Moving NRQCD (MNRQCD), a generalization of NRQCD which allows the treatment of heavy quarks moving with a finite velocity. This formalism is vital in reducing discretization errors in calculations of large ... More
Quantum computing and the entanglement frontierMar 26 2012Nov 10 2012Quantum information science explores the frontier of highly complex quantum states, the "entanglement frontier." This study is motivated by the observation (widely believed but unproven) that classical systems cannot simulate highly entangled quantum ... More
Do Black Holes Destroy Information?Sep 16 1992I review the information loss paradox that was first formulated by Hawking, and discuss possible ways of resolving it. All proposed solutions have serious drawbacks. I conclude that the information loss paradox may well presage a revolution in fundamental ... More
Adding flavor to Dijkgraaf-VafaNov 01 2002Jan 07 2003We study matrix models related via the correspondence of Dijkgraaf and Vafa to supersymmetric gauge theories with matter in the fundamental. As in flavorless examples, measure factors of the matrix integral reproduce information about R-symmetry violation ... More
Thermalization and Revivals after a Quantum Quench in Conformal Field TheoryMar 12 2014We consider a quantum quench in a finite system of length $L$ described by a 1+1-dimensional CFT, of central charge $c$, from a state with finite energy density corresponding to an inverse temperature $\beta\ll L$. For times $t$ such that $\ell/2<t<(L-\ell)/2$ ... More
Boundary Conformal Field TheoryNov 21 2004Feb 20 2008Boundary conformal field theory (BCFT) is simply the study of conformal field theory (CFT) in domains with a boundary. It gains its significance because, in some ways, it is mathematically simpler: the algebraic and geometric structures of CFT appear ... More
The Stress Tensor in Quenched Random SystemsNov 02 2001The talk describes recent progress in understanding the behaviour of the stress tensor and its correlation functions at a critical point of a generic quenched random system. The topics covered include:(i) the stress tensor in random systems considered ... More
Critical Exponents near a Random Fractal BoundaryDec 29 1998Jan 05 1999The critical behaviour of correlation functions near a boundary is modified from that in the bulk. When the boundary is smooth this is known to be characterised by the surface scaling dimension $\xt$. We consider the case when the boundary is a random ... More
Quenched Randomness at First-Order TransitionsJun 29 1998A rigorous theorem due to Aizenman and Wehr asserts that there can be no latent heat heat in a two-dimensional system with quenched random impurities. We examine this result, and its possible extensions to higher dimensions, in the context of several ... More
Effect of Random Impurities on Fluctuation-Driven First Order TransitionsNov 23 1995We analyse the effect of quenched uncorrelated randomness coupling to the local energy density of a model consisting of N coupled two-dimensional Ising models. For N>2 the pure model exhibits a fluctuation-driven first order transition, characterised ... More
Network Models in Class C on Arbitrary GraphsJun 22 2004We consider network models of quantum localisation in which a particle with a two-component wave function propagates through the nodes and along the edges of an arbitrary directed graph, subject to a random SU(2) rotation on each edge it traverses. The ... More
Crossing Formulae for Critical Percolation in an AnnulusAug 14 2002Sep 20 2002An exact formula is given for the probability that there exists a spanning cluster between opposite boundaries of an annulus, in the scaling limit of critical percolation. The entire distribution function for the number of distinct spanning clusters is ... More
Conformal Invariance and PercolationMar 14 2001Apr 05 2001These lectures give an introduction to the methods of conformal field theory as applied to deriving certain results in two-dimensional critical percolation: namely the probability that there exists at least one cluster connecting two disjoint segments ... More
Renormalisation Group Theory of Branching Potts InterfacesJun 08 1998Jul 15 1999We develop a field-theoretic representation for the configurations of an interface between two ordered phases of a q-state Potts model in two dimensions, in the solid-on-solid approximation. The model resembles the field theory of directed percolation ... More
Mean Area of Self-Avoiding LoopsOct 08 1993Oct 11 1993The mean area of two-dimensional unpressurised vesicles, or self-avoiding loops of fixed length $N$, behaves for large $N$ as $A_0 N^{3/2}$, while their mean square radius of gyration behaves as $R^2_0 N^{3/2}$. The amplitude ratio $A_0/R_0^2$ is computed ... More
Critical Percolation in Finite GeometriesNov 14 1991The methods of conformal field theory are used to compute the crossing probabilities between segments of the boundary of a compact two-dimensional region at the percolation threshold. These probabilities are shown to be invariant not only under changes ... More
Proportion of Unaffected Sites in a Reaction-Diffusion ProcessSep 12 1994Sep 13 1994We consider the probability $P(t)$ that a given site remains unvisited by any of a set of random walkers in $d$ dimensions undergoing the reaction $A+A\to0$ when they meet. We find that asymptotically $P(t)\sim t^{-\theta}$ with a universal exponent $\theta=\ffrac12-O(\epsilon)$ ... More
Improved Upper Bounds for Pairing HeapsOct 20 2011Jan 22 2014Pairing heaps are shown to have constant amortized time Insert and Meld, thus showing that pairing heaps have the same amortized runtimes as Fibonacci heaps for all operations but Decrease-key.
Generalizing the Dempster-Shafer Theory to Fuzzy SetsMar 27 2013With the desire to apply the Dempster-Shafer theory to complex real world problems where the evidential strength is often imprecise and vague, several attempts have been made to generalize the theory. However, the important concept in the D-S theory that ... More
No Spontaneous CP Violation at Finite Temperature in the MSSM?Oct 24 2000In order to generate the baryon asymmetry of the Universe sufficiently strong CP violation is needed. It was therefore proposed that at finite temperature there might be spontaneous (transitional) CP violation within the bubble walls at the electroweak ... More
Bubble Wall Profiles in Supersymmetric ModelsJan 15 1999We present solutions to the equations of motion for bubble wall profiles in the minimal and a non minimal supersymmetric extension of the Standard model. We discuss the method of the numerical approach and present results for the two models (MSSM and ... More
Interferometric Phase Estimation Though Quantum Filtering in Coherent StatesJan 18 2016We derive the form of the quantum filter equation describing the continuous observation of the phase of a quantum system in an arm of an interferometer via non-demolition measurements when the statistics of an input field used for the indirect measurement ... More
The Langevin equation from Markovian Quantum Central LimitsDec 05 2003Nov 18 2006This paper has been withdrawn by the author. The central result is now included in quant-ph/0309056 (as in the journal publication!). An erratum on the Heisenberg perturbation series estimate is also included therein.
How Well Do Standard Solar Models Describe the Results of Solar Neutrino Experiments?Jun 26 1996The neutrino fluxes calculated from the 14 standard solar models published recently in refereed journals are inconsistent with the results of the 4 pioneering solar neutrino experiments if nothing happens to the neutrinos after they are created in the ... More
Solving the Mystery of the Missing NeutrinosJun 09 2004The three years 2001 to 2003 were the golden years of solar neutrino research. In this period, scientists solved a mystery with which they had been struggling for four decades. The solution turned out to be important for both physics and for astronomy. ... More
Donaldson-Thomas Invariants and FlopsNov 07 2011Dec 14 2014We prove a comparison formula for the Donaldson-Thomas curve-counting invariants of two smooth and projective Calabi-Yau threefolds related by a flop. By results of Bridgeland any two such varieties are derived equivalent. Furthermore there exist pairs ... More
Muon Identification without IronSep 06 2007Muons can be identified with high efficiency and purity and reconstructed with high precision is a detector with a dual readout calorimeter and a dual solenoid to return the flux without iron. We shown CERN test beam data for the calorimeter and calculations ... More
Visualizing Astrophysical N-body SystemsMay 28 2008I begin with a brief history of N-body simulation and visualization and then go on to describe various methods for creating images and animations of modern simulations in cosmology and galactic dynamics. These techniques are incorporated into a specialized ... More
Viewpoint: duality for fermionic vorticesJul 07 2016This is a version (less professional editing, more details and jokes) of an APS Physics Viewpoint about three recent papers extending charge-vortex duality to fermionic vortices.
TASI lectures on quantum matter (with a view toward holographic duality)Jun 29 2016These are notes from my lectures at TASI 2015. The goal is to provide context for the study of strongly-correlated quantum many-body systems using quantum field theory, and possibly string theory.
Isocurvature and Curvaton Perturbations with Red Power Spectrum and Large Hemispherical AsymmetryMay 02 2013May 21 2013We calculate the power spectrum and hemispherical asymmetry of isocurvature and curvaton perturbations due to a complex field \Phi which is evolving along the tachyonic part of its potential. Using a semi-classical evolution of initially sub-horizon quantum ... More
Spectral Index of Curvaton Perturbations in Flat Potential Inflation ModelsAug 05 2003Aug 17 2003This paper has been withdrawn. Comments regarding D-term inflation will be incorporated in a forthcoming article.
B-ball Baryogenesis and D-term InflationJan 29 1999Feb 05 1999The MSSM has flat directions in its scalar potential, along which it is natural for Bose condensates of squarks to form in the early Universe. A baryon asymmetry can be induced in these condensates via Affleck-Dine baryogenesis. The condensates are unstable ... More
Sub-Planckian Two-Field Inflation Consistent with the Lyth BoundApr 17 2014Oct 24 2014The BICEP2 observation of a large tensor-to-scalar ratio, $r = 0.20^{+0.07}_{-0.05}$, implies that the inflaton $\phi$ in single-field inflation models must satisfy $\phi \sim 10M_{Pl}$ in order to produce sufficient inflation. This is a problem if interaction ... More
Hemispherical Power Asymmetry from a Space-Dependent Component of the Adiabatic Power SpectrumMar 09 2014Jun 17 2014The hemispherical power asymmetry observed by Planck and WMAP can be interpreted as due to a spatially-varying and scale-dependent component of the adiabatic power spectrum. We derive general constraints on the magnitude and scale-dependence of a component ... More
Hemispherical Power Asymmetry from Scale-Dependent Modulated ReheatingSep 04 2013Feb 20 2014We propose a new model for the hemispherical power asymmetry of the CMB based on modulated reheating. Non-Gaussianity from modulated reheating can be small enough to satisfy the bound from Planck if the dominant modulation of the inflaton decay rate is ... More
Baryon-to-Dark Matter Ratio from Random Angular FieldsNov 19 2012Jan 14 2013We consider the baryon-to-dark matter ratio in models where the dark matter and baryon densities depend on angular fields \theta_{d} and \theta_{b} according to \rho_{d} ~ \theta_{d}^{\alpha} and \rho_{b} ~ \theta_{b}^{\beta}, with all values of \theta_{d} ... More
Anthropically Selected Baryon Number and Isocurvature ConstraintsJul 09 2012Dec 23 2012The similarity of the observed baryon and dark matter densities suggests that they are physically related, either via a particle physics mechanism or anthropic selection. A pre-requisite for anthropic selection is the generation of superhorizon-sized ... More
Right-Handed Sneutrinos as CurvatonsFeb 25 2003Jul 29 2003We consider the possibility that a right-handed sneutrino can serve as the source of energy density perturbations leading to structure formation in cosmology. The cosmological evolution of a coherently oscillating condensate of right-handed sneutrinos ... More
Inflaton Condensate Fragmentation in Hybrid Inflation ModelsMay 22 2001Jul 09 2002Inflation ends with the formation of a Bose condensate of inflatons. We show that in hybrid inflation models this condensate is typically unstable with respect to spatial perturbations and can fragment to condensate lumps. The case of D-term inflation ... More
Two Dimensional Mirror Symmetry From M-theorySep 30 1997Oct 01 1997We construct two dimensional gauge theories with $N= (4,4)$ supersymmetry from branes of type IIA string theory. Quantum effects in the two dimensional gauge theory are analyzed by embedding the IIA brane construction into M-theory. We find that the Coulomb ... More
Comet: A VOEvent BrokerSep 16 2014The VOEvent standard provides a means of describing transient celestial events in a machine-readable format. This is an essential step towards analysing and, where appropriate, responding to the large volumes of transients which will be detected by future ... More
The radio background: radio-loud galaxies at high and low redshiftsJul 12 1993The majority of this paper is devoted to discrete radio sources, and their consequences for cosmology. Three main issues are considered: (i) what makes a galaxy radio loud?; (ii) what do we know about how the population of radio-loud galaxies has changed ... More
A seminormal form for partition algebrasFeb 10 2011Jul 03 2013Using a new presentation for partition algebras (J. Algebraic Combin. 37(3):401-454, 2013), we derive explicit combinatorial formulae for the seminormal representations of the partition algebras. These results generalise to the partition algebras the ... More
Fifty Years of IMF Variation: The Intermediate-Mass StarsDec 20 2004I track the history of star count estimates of the Milky Way field star and open cluster IMFs, concentrating on the neglected mass range from 1 to 15 M${_\odot}$. The prevalent belief in a universal IMF appears to be without basis for this mass range. ... More
The IMF Revisited: A Case for VariationsDec 23 1997Jan 05 1998A survey of results concerning the IMF derived from star counts is presented, including work up to, but not including, that presented in these proceedings. The situation regarding low-mass stars in the field and in clusters, high-mass stars and intermediate-mass ... More
Commentary on "The Theory of the Fluctuations in Brightness of the Milky Way. V" by S. Chandrasekhar and G. Munch (1952)Sep 14 1999The series of papers by Chandrasekhar and Munch in the 1950s were concerned with the use of statistical models to infer the properties of interstellar clouds based on the observed spatial brightness fluctuations of the Milky Way. The present paper summarizes ... More
The IMF in Young Galaxies: What Theory Might Tell UsNov 20 1998Observations have not yielded convincing results concerning the form of the stellar initial mass function (IMF) or its variations in space and time, so it is proposed that theoretical models may provide useful guidance. Several classes of theoretical ... More
A quick construction of mutually orthogonal sudoku squaresMar 02 2013For any odd prime power q we provide a quick construction of a complete family of q(q-1) mutually orthogonal sudoku squares of order q^2.
Grommet: an N-body code for high-resolution simulations of individual galaxiesMar 15 2007Nov 07 2007This paper presents a fast, economical particle-multiple-mesh N-body code optimized for large-N modelling of collisionless dynamical processes, such as black-hole wandering or bar-halo interactions, occurring within isolated galaxies. The code has been ... More
Glueballs and AdS/CFTApr 01 2002I review the calculation of the glueball spectrum in non-supersymmetric Yang-Mills theory (in 3 and 4 dimensions) using the conjectured duality between supergravity and large N gauge theories. The glueball masses are obtained by solving the supergravity ... More
Tevatron PhysicsJan 09 2003Jan 11 2003These lectures form a personal, and not necessarily comprehensive, survey of physics at the Fermilab Tevatron proton-antiproton collider. They cover detectors, analysis issues, and physics prospects for the current Tevatron run. (Version 2 has typographic ... More
The Top Quark - 2006 and BeyondApr 04 2006We know there is new physics at the electroweak scale, but we don't know what it is. Right now, the top quark is our only window on to this physics. In almost all models of electroweak symmetry breaking, top either couples strongly to new particles or ... More
A study of obliquely propagating longitudinal shear waves in a periodic laminateOct 24 2013The basic purpose of this work is to demonstrate, by quite simple and explicit calculation, the possibility that a simple laminate composed of ordinary materials can display the kind of response associated with a "metamaterial". Specifically, a wave of ... More
Generating Politically-Relevant Event DataSep 20 2016Automatically generated political event data is an important part of the social science data ecosystem. The approaches for generating this data, though, have remained largely the same for two decades. During this time, the field of computational linguistics ... More
Zeros of the Jimbo, Miwa, Ueno tau functionOct 06 1998We introduce a family of local deformations for meromorphic connections on the Riemann sphere in the neighborhood of a higher rank (simple) singularity. Following a scheme introduced by Malgrange we use these local models to prove that the zeros of the ... More
Exotic Statistics for Ordinary Particles in Quantum GravityMay 15 2008Objects exhibiting statistics other than the familiar Bose and Fermi ones are natural in theories with topologically nontrivial objects including geons, strings, and black holes. It is argued here from several viewpoints that the statistics of ordinary ... More
On the Possibility of Large Upconversions and Mode Coupling between Frohlich States and Visible Photons in Biological SystemsMar 16 2006At least two significant roles for large scale quantum coherence in living systems have been suggested: Herbert Fr\"{o}hlich's coherent excitations of nonlinearly coupled ensembles of large polarizable molecules, with frequencies in the microwave region, ... More
Measuring Newton's Gravitational Constant With a Gravitational OscillatorMay 20 2014Newton's gravitational constant G, which determines the strength of gravitational interactions both in Newton's theory and in Einstein's General Relativity, is the least well known of all the fundamental constants. Given its importance, and with recent ... More
The Pauli Exclusion Principle, Spin, and Statistics in Loop Quantum Gravity: SU(2) versus SO(3)Feb 22 2004Mar 29 2004Recent attempts to resolve the ambiguity in the loop quantum gravity description of the quantization of area has led to the idea that j=1 edges of spin-networks dominate in their contribution to black hole areas as opposed to j=1/2 which would naively ... More
Particles, Fields, Pomerons and BeyondOct 23 2011This paper is a set of musings on what particles really are -- something one all too often as a particle physicist assumes is pretty well-established. The initial motivation for these thoughts comes from a question that I always ask Alberto Santoro whenever ... More
The recursion hierarchy for PCF is strictJul 15 2016Let $PCF_k$ denote the sublanguage of Plotkin's PCF in which fixed point operators $Y_\sigma$ are admitted only for types $\sigma$ of level $\leq k$. We show that the languages $PCF_k$ form a strict hierarchy, in the sense that none of the $Y_\sigma$ ... More
Cybersusy Solves the Cosmological Constant ProblemJun 11 2010Jun 15 2016Cybersusy is a new mechanism for SUSY breaking. When the auxiliary fields are integrated in any theory like the SSM, certain special new composite superfields arise. Spontaneous breaking of internal symmetry, like SU(2) X U(1) to U(1), gives rise to a ... More
Chiral SUSY Theories with a Suppressed SUSY ChargeApr 21 2016May 18 2016The well-known Chiral and Gauge SUSY Actions realize the SUSY charge in terms of transformations among the Fields. These transformations are included in the Master Equation by coupling them to Sources. Here we show that there are new local SUSY Actions ... More
Introduction to the BRS Cohomology of the Massless Wess Zumino Model: Cybersusy IIAug 16 2008This paper is the second paper in a series of four papers that introduce cybersusy, which is a new method for analyzing supersymmetry breaking in the standard supersymmetric model (SSM). The first paper was a summary of the results and the three next ... More
Supersymmetry Breaks when Gauge Symmetry Breaks: Cybersusy IAug 06 2008This paper summarizes a new approach to supersymmetry breaking in the supersymmetric standard model (SSM). The approach arises from some remarkable features of the BRS cohomology for composite operators in the SSM, and the behaviour of those operators ... More
Unpolarized nucleon structure studies utilizing polarized electromagnetic probesJan 23 2009By the mid-1980s, measurements of the nucleon form factors had reached a stage where only slow, incremental progress was possible using unpolarized electron scattering. The development of high quality polarized beams, polarized targets, and recoil polarimeters ... More
Coulomb corrections in the extraction of the proton radiusOct 09 2012Sep 06 2013Multi-photon exchange contributions are important in extracting the proton charge radius from elastic electron--proton scattering. So far, only diagrams associated with the exchange of a second photon have been evaluated. At the very low $Q^2$ values ... More
Double riches: asteroseismology in eclipsing binariesSep 11 2015The study of eclipsing binaries is our primary source of measured properties of normal stars, achieved through analysis of light and radial velocity curves of eclipsing systems. The study of oscillations and pulsations is increasingly vital for determining ... More
Multiple star systems observed with CoRoT and Kepler (invited review)Oct 30 2014Nov 10 2014The CoRoT and Kepler satellites were the first space platforms designed to perform high-precision photometry for a large number of stars. Multiple systems display a wide variety of photometric variability, making them natural benefactors of these missions. ... More