The Pioneer anomaly: the measure of a topological phase defect of light in cosmology

It is shown that a wave vector representing a light pulse in an adiabatically evolving expanding space should develop, after a round trip (back and forth to the emitter) a geometric phase for helicity states at a given fixed position coordinate of this expanding space.In a section of the Hopf fibration of the Poincare sphere that identifies a projection to the physically allowed states, the evolution defines a parallel transported state that can be joined continuously with the initial state by means of the associated Berry-Pancharatnam connection. The connection allows to compute an anomaly in the frequency for the vector modes in terms of the scale factor of the space-time background being identical to the reported Pioneer Anomaly.Comment: 10 pages, some minor notation changes have been made. Some additional remarks were writte

Deformation of liquid drops containing ions in the presence of an electric field

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The deformation and breakup of a conducting water drop immersed in hexadecane in the presence of an electric field is investigated using a numerical tool for a range of field strengths and ion concentrations. At low electric field strengths, the drop deformation is a linear function of the electric capillary number. For high electric field strengths, the dependence is no longer linear, and significant drop deformation occurs. The drop deformation increases with increasing ion concentration, due to a separation of ions within the drop, leading to a redistribution of charge at either end of the drop.dc201

Exact asymptotics of the freezing transition of a logarithmically correlated random energy model

We consider a logarithmically correlated random energy model, namely a model for directed polymers on a Cayley tree, which was introduced by Derrida and Spohn. We prove asymptotic properties of a generating function of the partition function of the model by studying a discrete time analogy of the KPP-equation - thus translating Bramson's work on the KPP-equation into a discrete time case. We also discuss connections to extreme value statistics of a branching random walk and a rescaled multiplicative cascade measure beyond the critical point

Decay of Classical Chaotic Systems - the Case of the Bunimovich Stadium

The escape of an ensemble of particles from the Bunimovich stadium via a small hole has been studied numerically. The decay probability starts out exponentially but has an algebraic tail. The weight of the algebraic decay tends to zero for vanishing hole size. This behaviour is explained by the slow transport of the particles close to the marginally stable bouncing ball orbits. It is contrasted with the decay function of the corresponding quantum system.Comment: 16 pages, RevTex, 3 figures are available upon request from [email protected], to be published in Phys.Rev.

Accidental Degeneracy and Berry Phase of Resonant States

We study the complex geometric phase acquired by the resonant states of an open quantum system which evolves irreversibly in a slowly time dependent environment. In analogy with the case of bound states, the Berry phase factors of resonant states are holonomy group elements of a complex line bundle with structure group C*. In sharp contrast with bound states, accidental degeneracies of resonances produce a continuous closed line of singularities formally equivalent to a continuous distribution of "magnetic" charge on a "diabolical" circle, in consequence, we find different classes of topologically inequivalent non-trivial closed paths in parameter space.Comment: 23 pages, 2 Postscript figures, LaTex, to be published in: Group 21: Symposium on Semigroups and Quantum Irreversibility (Proc. of the XXI Int. Colloquium on Group Theoretical Methods in Physics

On Fields with Finite Information Density

The existence of a natural ultraviolet cutoff at the Planck scale is widely expected. In a previous Letter, it has been proposed to model this cutoff as an information density bound by utilizing suitably generalized methods from the mathematical theory of communication. Here, we prove the mathematical conjectures that were made in this Letter.Comment: 31 pages, to appear in Phys.Rev.

Tops and Writhing DNA

The torsional elasticity of semiflexible polymers like DNA is of biological significance. A mathematical treatment of this problem was begun by Fuller using the relation between link, twist and writhe, but progress has been hindered by the non-local nature of the writhe. This stands in the way of an analytic statistical mechanical treatment, which takes into account thermal fluctuations, in computing the partition function. In this paper we use the well known analogy with the dynamics of tops to show that when subjected to stretch and twist, the polymer configurations which dominate the partition function admit a local writhe formulation in the spirit of Fuller and thus provide an underlying justification for the use of Fuller's "local writhe expression" which leads to considerable mathematical simplification in solving theoretical models of DNA and elucidating their predictions. Our result facilitates comparison of the theoretical models with single molecule micromanipulation experiments and computer simulations.Comment: 17 pages two figure

Chaotic Diffusion on Periodic Orbits: The Perturbed Arnol'd Cat Map

Chaotic diffusion on periodic orbits (POs) is studied for the perturbed Arnol'd cat map on a cylinder, in a range of perturbation parameters corresponding to an extended structural-stability regime of the system on the torus. The diffusion coefficient is calculated using the following PO formulas: (a) The curvature expansion of the Ruelle zeta function. (b) The average of the PO winding-number squared, $w^{2}$, weighted by a stability factor. (c) The uniform (nonweighted) average of $w^{2}$. The results from formulas (a) and (b) agree very well with those obtained by standard methods, for all the perturbation parameters considered. Formula (c) gives reasonably accurate results for sufficiently small parameters corresponding also to cases of a considerably nonuniform hyperbolicity. This is due to {\em uniformity sum rules} satisfied by the PO Lyapunov eigenvalues at {\em fixed} $w$. These sum rules follow from general arguments and are supported by much numerical evidence.Comment: 6 Tables, 2 Figures (postscript); To appear in Physical Review

A Gravitational Aharonov-Bohm Effect, and its Connection to Parametric Oscillators and Gravitational Radiation

A thought experiment is proposed to demonstrate the existence of a gravitational, vector Aharonov-Bohm effect. A connection is made between the gravitational, vector Aharonov-Bohm effect and the principle of local gauge invariance for nonrelativistic quantum matter interacting with weak gravitational fields. The compensating vector fields that are necessitated by this local gauge principle are shown to be incorporated by the DeWitt minimal coupling rule. The nonrelativistic Hamiltonian for weak, time-independent fields interacting with quantum matter is then extended to time-dependent fields, and applied to problem of the interaction of radiation with macroscopically coherent quantum systems, including the problem of gravitational radiation interacting with superconductors. But first we examine the interaction of EM radiation with superconductors in a parametric oscillator consisting of a superconducting wire placed at the center of a high Q superconducting cavity driven by pump microwaves. We find that the threshold for parametric oscillation for EM microwave generation is much lower for the separated configuration than the unseparated one, which then leads to an observable dynamical Casimir effect. We speculate that a separated parametric oscillator for generating coherent GR microwaves could also be built.Comment: 25 pages, 5 figures, YA80 conference (Chapman University, 2012

Perceptions of COVID-19 vaccines among healthcare assistants: A national survey

Background: Limited COVID-19 vaccination acceptance among healthcare assistants (HCAs) may adversely impact older adults, who are at increased risk for severe COVID-19 infections. Our study objective was to evaluate the perceptions of COVID-19 vaccine safety and efficacy in a sample of frontline HCAs, overall and by race and ethnicity. Methods: An online survey was conducted from December 2020 to January 2021 through national e-mail listserv and private Facebook page for the National Association of Health Care Assistants. Responses from 155 HCAs, including certified nursing assistants, home health aides, certified medical assistants, and certified medication technicians, were included. A 27-item survey asked questions about experiences and perceptions of COVID-19 vaccines, including how confident they were that COVID-19 vaccines are safe, effective, and adequately tested in people of color. Multivariable regression was used to identify associations with confidence in COVID-19 vaccines. Results: We analyzed data from 155 completed responses. Among respondents, 23.9% were black and 8.4% Latino/a. Most respondents worked in the nursing home setting (53.5%), followed by hospitals (12.9%), assisted living (11.6%), and home care (10.3%). Respondents expressed low levels of confidence in COVID-19 vaccines, with fewer than 40% expressing at least moderate confidence in safety (38.1%), effectiveness (31.0%), or adequate testing in people of color (27.1%). Non-white respondents reported lower levels of confidence in adequate testing of vaccines compared to white respondents. In bivariate and adjusted models, respondents who gave more favorable scores of organizational leadership at their workplace expressed greater confidence in COVID-19 vaccines. Conclusion: Frontline HCAs reported low confidence in COVID-19 vaccines. Stronger organizational leadership in the workplace appears to be an important factor in influencing HCA's willingness to be vaccinated. Action is needed to enhance COVID-19 vaccine uptake in this important population with employers playing an important role to build vaccine confidence and trust among employees. © 2021 The American Geriatrics Society