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The observation of gravitational waves by the three LIGO-Virgo interferometers allows the examination of the polarization of gravitational waves. Here we analyze the binary neutron star event GW170817, whose source location and distance are determined precisely by concurrent electromagnetic observations. Applying a signal accumulation procedure to the LIGO-Virgo strain data, we find ratios of the signals detected by the three interferometers. We conclude that the signal ratios are inconsistent with the predictions of general relativity, but consistent with the recently proposed vector theory of gravity [Phys. Scr. 92, 125001 (2017)]. Moreover, we find that vector gravity yields a distance to the source in agreement with the astronomical observations. If our analysis is correct, Einstein's general theory of relativity is ruled out in favor of vector gravity at 99% confidence level and future gravitational wave detections by three or more observatories should confirm this conclusion with higher precision., Comment: 18 pages, 23 figures. We added section on Null stream analysis which supports our conclusion. Eur. Phys. J. Spec. Top. (2021)

To determine the polarization character of gravitational waves, we use strain data from the GW170814 binary black hole coalescence event detected by the three LIGO-Virgo observatories, extracting the gravitational wave strain signal amplitude ratios directly from those data. Employing a geometric approach that links those ratios to the gravitational wave polarization properties, we find that there is a range of source sky locations, partially overlapping the LIGI-Virgo 90% credible range of GW170814 source locations, for which vector polarization is consistent with the observed amplitude ratios. A Bayesian inference analysis indicates that the GW170814 data cannot rule out vector polarization for gravitational waves. Confirmation of a vector polarization component of gravitational waves would be a sign of post-general relativity physics., Comment: This version adds (1) enhanced analysis of the raw LIGO-Virgo strain data and (2) Bayesian inference methods for testing polarization models

This tutorial leads the reader through the details of calculating the properties of gravitational waves from orbiting binaries, such as two orbiting black holes. Using analogies with electromagnetic radiation, the tutorial presents a calculation that produces the same dependence on the masses of the orbiting objects, the orbital frequency, and the mass separation as does the linear version of General Relativity (GR). However, the calculation yields polarization, angular distributions, and overall power results that differ from those of GR. Nevertheless, the calculation produces waveforms that are nearly identical to the pre-binary-merger portions of the signals observed by the Laser Interferometer Gravitational-Wave Observatory (LIGO-Virgo) collaboration. The tutorial should be easily understandable by students who have taken a standard upper-level undergraduate course in electromagnetism., Comment: Version 2 of this tutorial adds the integrated orbital phase method of describing chirp signals and a detailed derivation of the interaction of a vector gravitational wave with a LIGO-Virgo interferometer detector

We explore the connection between a stochastic simulation model and an ordinary differential equations (ODEs) model of the dynamics of an excitable gene circuit that exhibits noise-induced oscillations. Near a bifurcation point in the ODE model, the stochastic simulation model yields behavior dramatically different from that predicted by the ODE model. We analyze how that behavior depends on the gene copy number and find very slow convergence to the large number limit near the bifurcation point. The implications for understanding the dynamics of gene circuits and other birth-death dynamical systems with small numbers of constituents are discussed., Comment: PLoS ONE: Research Article, published 11 Apr 2012

Strategic Programs for Innovations in Undergraduate Physics (SPIN-UP) set out to answer an intriguing question: Why, in the 1990s, did some physics departments increase the number of bachelor's degrees awarded in physics or maintain a number much higher than the national average for their type of institution? During that decade, the number of bachelor's degrees awarded in the physical sciences, engineering, and mathematics declined across the country. Yet in the midst of this decline some departments had thriving programs. What made these departments different? What lessons can be learned to help departments in the sciences, engineering, and mathematics that are--to put it generously--less than thriving? SPIN-UP, a project of the National Task Force on Undergraduate Physics, set out to answer these questions by sending site visit teams to 21 physics departments whose undergraduate programs were, by various measures, thriving. These visits took place mostly during the 2001-2002 academic year. In addition, with the aid of the American Institute of Physics Statistical Research Center, SPIN-UP developed a survey sent to all 759 departments in the United States that grant bachelor's degrees in physics. The survey yielded a 74% response rate distributed broadly across the spectrum of U.S. physics departments. The site visit reports provided specific insight into what makes an undergraduate physics program thrive. In very compact form, these departments all have: (1) A widespread attitude among the faculty that the department has the primary responsibility for maintaining or improving the undergraduate program; (2) A challenging, but supportive and encouraging undergraduate program; (3) Strong and sustained leadership within the department and a clear sense of the mission of its undergraduate program; and (4) A strong disposition toward continuous evaluation of and experimentation with the undergraduate program. In Chapter 4 of this report, each of these themes is further analyzed and illustrated with examples from the site visit departments. Chapter 5 provides a summary of the survey results. Eight appendices are included: (1) Physics Education Resources; (2) Undergraduate Physics Reading List; (3) Presentations and Articles on SPIN-UP; (4) Site Visit Volunteers; (5) Site Visit Documentation; (6) Formative Evaluator's Report; (7) Survey Form; and (8) Case Study Documents. (Contains 10 tables.)

We show that noise-induced oscillations in a gene circuit model display stochastic coherence, that is, a maximum in the regularity of the oscillations as a function of noise amplitude. The effect is manifest as a system-size effect in a purely stochastic molecular reaction description of the circuit dynamics. We compare the molecular reaction model behavior with that predicted by a rate equation version of the same system. In addition, we show that commonly used reduced models that ignore fast operator reactions do not capture the full stochastic behavior of the gene circuit. Stochastic coherence occurs under conditions that may be physiologically relevant.

We demonstrate the existence of noise-induced periodicity (coherence resonance) in both a discrete-time model and a continuous-time model of an excitable neuron. In particular, we show that the effects of noise added to the fast and slow dynamics of the models are dramatically different. A Fokker-Planck analysis gives a quantitative explanation of the effects.

The relationships among various parameters describing the strength of optical transitions in atoms and molecules are reviewed. The application of these parameters to the description of the interaction between nearly monochromatic, directional light beams and atoms and molecules is given careful attention. Common pitfalls in relating these parameters are pointed out. This is a revised (February, 2002) version of a paper that originally appeared in Am. J. Phys. 50, 982-986 (1982).

The quon algebra gives a description of particles, ``quons,'' that are neither fermions nor bosons. The parameter $q$ attached to a quon labels a smooth interpolation between bosons, for which $q = +1$, and fermions, for which $q = -1$. Wigner and Ehrenfest and Oppenheimer showed that a composite system of identical bosons and fermions is a fermion if it contains an odd number of fermions and is a boson otherwise. Here we generalize this result to composite systems of identical quons. We find $q_{composite}=q_{constituent}^{n^2}$ for a system of $n$ identical quons. This result reduces to the earlier result for bosons and fermions. Using this generalization we find bounds on possible violations of the Pauli exclusion principle for nucleons and quarks based on such bounds for nuclei., Comment: 10 pages, Latex, no figures

Quons are particles characterized by the parameter $q$, which permits smooth interpolation between Bose and Fermi statistics; $q=1$ gives bosons, $q=-1$ gives fermions. In this paper we give a heuristic argument for an extension of conservation of statistics to quons with trilinear couplings of the form $\bar{f}fb$, where $f$ is fermion-like and $b$ is boson-like. We show that $q_f^2=q_b$. In particular, we relate the bound on $q_{\gamma}$ for photons to the bound on $q_e$ for electrons, allowing the very precise bound for electrons to be carried over to photons. An extension of this argument suggests that all particles are fermions or bosons to high precision., Comment: 10 pages, no figures, issue of Foundations of Physics in honor of D.M. Greenberger