WorldWideScience

Sample records for anomalous flux-ratio gravitational

  1. Multipole Models of Four-Image Gravitational Lenses with Anomalous Flux Ratios

    CERN Document Server

    Congdon, A B; Congdon, Arthur B.; Keeton, Charles R.

    2005-01-01

    Anomalous radio flux ratios in four-image gravitational lens systems can be explained by adding a clumpy cold dark matter (CDM) component to the potential of the lens galaxy. Evans & Witt (2003) recently suggested that smooth multipole perturbations can provide a reasonable alternative to CDM substructure in some but not all cases. We generalize their method in two ways so as to determine whether multipole models can explain highly anomalous systems. We carry the multipole expansion to higher order, and also include external tidal shear as a free parameter. Fitting for the shear proves crucial to finding a physical (positive-definite density) model. For B1422+231, working to order k = 5 (and including shear) yields a model that is physical but implausible. Going to higher order (k >~ 9) reduces global departures from ellipticity at the cost of introducing small scale wiggles near the bright images. These localized undulations are more pronounced in B2045+265, where k ~ 17 multipoles are required to smooth...

  2. SHARP - II: Revealing a bias in observational measurements of dark matter substructure with gravitational lens flux ratios

    CERN Document Server

    Hsueh, J - W; Vegetti, S; McKean, J P; Spingola, C; Auger, M W; Koopmans, L V E; Lagattuta, D J

    2016-01-01

    Gravitational lens flux-ratio anomalies provide a powerful technique for measuring dark matter substructure in distant galaxies. However, before using these flux-ratio anomalies to test galaxy formation models, it is imperative to ascertain that the given anomalies are indeed due to the presence of dark matter substructure and not due to some other component of the lensing galaxy halo or to propagation effects. Here we present the case of CLASS~B1555+375, which has a strong radio-wavelength flux-ratio anomaly. Our high-resolution near-infrared Keck~II adaptive optics imaging and archival Hubble Space Telescope data reveal the lensing galaxy in this system to have a clear edge-on disc component that crosses directly over the pair of images that exhibit the flux-ratio anomaly. We find simple models that include the disc can reproduce the cm-wavelength flux-ratio anomaly without requiring additional dark matter substructure. Although further studies are required, our results suggest the assumption that all flux-...

  3. Anomalous CMB polarization and gravitational chirality

    CERN Document Server

    Contaldi, Carlo R; Smolin, Lee

    2008-01-01

    We consider the possibility that gravity breaks parity, with left and right handed gravitons coupling to matter with a different Newton's constant and show that this would affect their zero-point vacuum fluctuations during inflation. Should there be a cosmic background of gravity waves, the effect would translate into anomalous CMB polarization. Non-vanishing TB (and EB) polarization components emerge, revealing interesting experimental targets. Indeed if reasonable chirality is present a TB measurement would provide the easiest way to detect a gravitational wave background. We speculate on the theoretical implications of such an observation.

  4. Anomalous effects due to the inertial anti-gravitational potential of the sun

    OpenAIRE

    Khokhlov, D. L.

    2007-01-01

    It is introduced inertial anti-gravitational potential into the theory of gravity to stop gravitational collapse at the nuclear density and thus prevent singularities. It is considered effective gravity which includes Newtonian potential and inertial anti-gravitational potential. It is investigated footprints of the effective gravity in the solar system. The inertial anti-gravitational potential of the sun allows to explain the anomalous acceleration of Pioneer 10 and 11, the anomalous increa...

  5. Piercing the Vainshtein screen with anomalous gravitational wave speed: Constraints on modified gravity from binary pulsars

    OpenAIRE

    Beltrán Jiménez, Jose; Piazza, Federico; Velten, Hermano

    2016-01-01

    International audience By using observations of the Hulse-Taylor pulsar we constrain the gravitational wave (GW) speed to the level of 10 −2. We apply this result to scalar-tensor theories that generalize Galileon 4 and 5 models, which display anomalous propagation speed and coupling to matter for GWs. We argue that this effect survives conventional screening due to the persistence of a scalar field gradient inside virialized overdensities, which effectively " pierces " the Vainshtein scre...

  6. Anomalous Polarization-Curvature Interaction in a Gravitational-Wave Field

    OpenAIRE

    Balakin, Alexander; Kurbanova, Veronika

    2004-01-01

    An exact solution to the dynamic equations for a massive boson traveling in a pp-wave gravitational background under the influence of the force induced by curvature, is presented. We focus on the effect of anomalous polarization-curvature interaction and consider models in which the coupling constant of such an interaction is treated to be either a deterministic quantity or a random variable.

  7. Evading the Vainshtein Mechanism with Anomalous Gravitational Wave Speed: Constraints on Modified Gravity from Binary Pulsars.

    Science.gov (United States)

    Beltrán Jiménez, Jose; Piazza, Federico; Velten, Hermano

    2016-02-12

    By using observations of the Hulse-Taylor pulsar, we constrain the gravitational wave (GW) speed to the level of 10^{-2}. We apply this result to scalar-tensor theories that generalize Galileon 4 and 5 models, which display anomalous propagation speed and coupling to matter for GWs. We argue that this effect survives conventional screening due to the persistence of a scalar field gradient inside virialized overdensities, which effectively "pierces" the Vainshtein screening. In specific branches of solutions, our result allows us to directly constrain the cosmological couplings in the effective field theory of dark energy formalism. PMID:26918974

  8. Anomalous character of the axion–photon coupling in a magnetic field distorted by a pp-wave gravitational background

    International Nuclear Information System (INIS)

    We study the problem of axion–photon coupling in the magnetic field influenced by gravitational radiation. We focus on exact solutions to the equations for axion electrodynamics in the pp-wave gravitational background for two models with initially constant magnetic field. The first model describes the response of an initially constant magnetic field in a gravitational-wave vacuum with unit refraction index; the second model is characterized by a non-unit refraction index prescribed to the presence of ordinary and/or dark matter. We show that both models demonstrate anomalous behavior of the electromagnetic field generated by the axion–photon coupling in the presence of magnetic field, evolving in the gravitational wave background. The role of axionic dark matter in the formation of the anomalous response of this electrodynamic system is discussed. (paper)

  9. Particle with spin 2 and anomalous magnetic moment in external electromagnetic and gravitational fields

    CERN Document Server

    Kisel, V V; Red'kov, V M

    2011-01-01

    Tensor 50-component form of the first order relativistic wave equation for a particle with spin 2 and anomalous magnetic moment is extended to the case of an arbitrary curved space-time geometry. An additional parameter considered in the presence of only electromagnetic field as related to anomalous magnetic moment, turns to determine additional interaction terms with external geometrical background through Ricci R_{kl} and Riemann R_{klmn} tensors.

  10. Fitting Gravitational Lenses Truth or Delusion

    CERN Document Server

    Evans, N W

    2003-01-01

    The observables in a strong gravitational lens are usually just the image positions and sometimes the flux ratios. We develop a new and simple algorithm which allows a set of models to be fitted exactly to the observations. Taking our cue from the strong body of evidence that early-type galaxies are close to isothermal, we assume that the lens is scale-free with a flat rotation curve. However, our algorithm allows full flexibility as regards the angular structure of the lensing potential. Importantly, all the free parameters enter linearly into the model and so the lens and flux ratio equations can always be solved by straightforward matrix inversion. We use this new algorithm to examine some of the claims made for substructure on the basis of "anomalous flux ratios". We demonstrate by explicit construction that some of the lenses for which substructure has been claimed can be well-fit by smooth lens models. This is especially the case when the systematic errors in the flux ratios (caused by microlensing or d...

  11. Gravitational Encounters and the Evolution of Galactic Nuclei. III. Anomalous Relaxation

    CERN Document Server

    Merritt, David

    2015-01-01

    This paper is the third in a series presenting the results of direct numerical integrations of the Fokker-Planck equation for stars orbiting a supermassive black hole (SBH) at the center of a galaxy. The algorithm of Paper II included diffusion coefficients that described the effects of random ("classical") and correlated ("resonant") relaxation. In this paper, the diffusion coefficients of Paper II have been generalized to account for the effects of "anomalous relaxation," the qualitatively different way in which eccentric orbits evolve in the regime of rapid relativistic precession. Two functional forms for the anomalous diffusion coefficients are investigated, based on power-law or exponential modifications of the resonant diffusion coefficients. The parameters defining the modified coefficients are first constrained by comparing the results of Fokker-Planck integrations with previously-published N-body integrations. Steady-state solutions are then obtained via the Fokker-Planck equation for models with pr...

  12. Fitting gravitational lenses: truth or delusion

    Science.gov (United States)

    Evans, N. Wyn; Witt, Hans J.

    2003-11-01

    The observables in a strong gravitational lens are usually just the image positions and sometimes the flux ratios. We develop a new and simple algorithm which allows a set of models to be fitted exactly to the observations. Taking our cue from the strong body of evidence that early-type galaxies are close to isothermal, we assume that the lens is scale-free with a flat rotation curve. External shear can be easily included. Our algorithm allows full flexibility regarding the angular structure of the lensing potential. Importantly, all the free parameters enter linearly into the model and so the lens and flux ratio equations can always be solved by straightforward matrix inversion. The models are only restricted by the fact that the surface mass density must be positive. We use this new algorithm to examine some of the claims made for anomalous flux ratios. It has been argued that such anomalies betray the presence of substantial amounts of substructure in the lensing galaxy. We demonstrate by explicit construction that some of the lens systems for which substructure has been claimed can be well fitted by smooth lens models. This is especially the case when the systematic errors in the flux ratios (caused by microlensing or differential extinction) are taken into account. However, there is certainly one system (B1422+231) for which the existing smooth models are definitely inadequate and for which substructure may be implicated. Within a few tens of kpc of the lensing galaxy centre, dynamical friction and tidal disruption are known to be very efficient at dissolving any substructure. Very little substructure is projected within the Einstein radius. The numbers of strong lenses for which substructure is currently being claimed may be so large that this contradicts rather than supports cold dark matter theories.

  13. Gravitation

    CERN Multimedia

    Without gravity, you would float into space. Gravity pulls matter together: it holds us onto the Earth, it holds the Earth in orbit around the sun and it holds our solar system in orbit about the centre of the galaxy. Everything with mass feels the attraction of gravity. The strength of the attraction between 2 objects depends on their masses. Despite its omnipresence, gravity is the weakest of the 4 forces. It is insignificant at the scale of human beings: when a group of visitors walks past, gravity doesn't pull you towards them! At even smaller scales, the gravitational pull between the electron and the proton is about 1040 times weaker than the electromagnetic attraction between them. Text for the interactive: Why does the same mass weigh more on the Earth than on the moon ?

  14. How well can cold-dark-matter substructures account for the observed lensing flux-ratio anomalies?

    CERN Document Server

    Xu, D D; Gao, Liang; Wang, Jie; Frenk, Carlos; Mao, Shude; Schneider, Peter

    2013-01-01

    Lensing flux-ratio anomalies are most likely caused by gravitational lensing by small-scale dark matter structures. These anomalies offer the prospect of testing a fundamental prediction of the cold dark matter (CDM) cosmological model: the existence of numerous substructures that are too small to host visible galaxies. In two previous studies we found that the number of subhalos in the six high-resolution simulations of CDM galactic halos of the Aquarius project is not sufficient to account for the observed frequency of flux ratio anomalies seen in selected quasars from the CLASS survey. These studies were limited by the small number of halos used, their narrow range of masses (1-2E12 solar masses) and the small range of lens ellipticities considered. We address these shortcomings by investigating the lensing properties of a large sample of halos with a wide range of masses in two sets of high resolution simulations of cosmological volumes and comparing them to a currently best available sample of radio quas...

  15. Reanalyses of Anomalous Gravitational Microlensing Events in the OGLE-III Early Warning System Database with Combined Data

    CERN Document Server

    Jeong, J; Han, C; Gould, A; Udalski, A; Szymański, M K; Pietrzyński, G; Soszyński, I; Poleski, R; Ulaczyk, K; Wyrzykowski, Ł; Abe, F; Bennett, D P; Bond, I A; Botzler, C S; Freeman, M; Fukui, A; Fukunaga, D; Itow, Y; Koshimoto, N; Masuda, K; Matsubara, Y; Muraki, Y; Namba, S; Ohnishi, K; Rattenbury, N J; Saito, To; Sullivan, D J; Sweatman, W L; Sumi, T; Suzuki, D; Tristram, P J; Tsurumi, N; Wada, K; Yamai, N; Yock, P C M; Yonehara, A; Albrow, M D; Batista, V; Beaulieu, J -P; Caldwell, J A R; Cassan, A; Cole, A; Coutures, C; Dieters, S; Dominik, M; Prester, D Dominis; Donatowicz, J; Fouqué, P; Greenhill, J; Hoffman, M; Huber, M; Jørgensen, U G; Kane, S R; Kubas, D; Martin, R; Marquette, J -B; Menzies, J; Pitrou, C; Pollard, K; Sahu, K C; Vinter, C; Wambsganss, J; Williams, A; Allen, W; Bolt, G; Choi, J -Y; Christie, G W; DePoy, D L; Drummond, J; Gaudi, B S; Hwang, K -H; Jung, Y K; Lee, C -U; Mallia, F; Maoz, D; Maury, A; McCormick, J; Monard, L A G; Moorhouse, D; Natusch, T; Ofek, E O; Park, B -G; Pogge, R W; Santallo, R; Shin, I -G; Thornley, G; Yee, J C; Bramich, D M; Horne, K; Hundertmark, M; Kains, N; Snodgrass, C; Steele, I; Street, R; Tsapras, Y

    2015-01-01

    We reanalyze microlensing events in the published list of anomalous events that were observed from the OGLE lensing survey conducted during 2004-2008 period. In order to check the existence of possible degenerate solutions and extract extra information, we conduct analyses based on combined data from other survey and follow-up observation and consider higher-order effects. Among the analyzed events, we present analyses of 8 events for which either new solutions are identified or additional information is obtained. We find that the previous binary-source interpretations of 5 events are better interpreted by binary-lens models. These events include OGLE-2006-BLG-238, OGLE-2007-BLG-159, OGLE-2007-BLG-491, OGLE-2008-BLG-143, and OGLE-2008-BLG-210. With additional data covering caustic crossings, we detect finite-source effects for 6 events including OGLE-2006-BLG-215, OGLE-2006-BLG-238, OGLE-2006-BLG-450, OGLE-2008-BLG-143, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. Among them, we are able to measure the Einstein ...

  16. Sodium flux ratio through the amiloride-sensitive entry pathway in frog skin

    OpenAIRE

    1983-01-01

    The sodium flux ratio of the amiloride-sensitive Na+ channel in the apical membrane of in vitro Rana catesbeiana skin has been evaluated at different sodium concentrations and membrane potentials in sulfate Ringer solution. Amiloride-sensitive unidirectional influxes and effluxes were determined as the difference between bidirectional 22Na and 24Na fluxes simultaneously measured in the absence and presence of 10(-4) M amiloride in the external bathing solution. Amiloride- sensitive Na+ efflux...

  17. On the origin of the flux ratio anomaly in quadruple lens systems

    Science.gov (United States)

    Inoue, Kaiki Taro

    2016-09-01

    We explore the origin of the flux ratio anomaly in quadruple lens systems. Using a semi-analytic method based on N-body simulations, we estimate the effect of a possible magnification perturbation caused by subhaloes with a mass scale of ≲109 h-1 M⊙ in lensing galaxy haloes. Taking into account astrometric shifts and assuming that the primary lens is described by a singular isothermal ellipsoid, the expected change to the flux ratios for a multiply lensed image is just a few per cent and the mean of the expected convergence perturbation at the effective Einstein radius of the lensing galaxy halo is = 0.003, corresponding to the mean of the ratio of a projected dark matter mass fraction in subhaloes at the effective Einstein radius = 0.006. In contrast, the expected change to the flux ratio caused by line-of-sight structures is typically ˜10 per cent and the mean of the convergence perturbation is = 0.008, corresponding to = 0.017. The contribution of the magnification perturbation caused by subhaloes is ˜40 per cent of the total at a source redshift zS = 0.7 and decreases monotonically in zS to ˜20 per cent at zS = 3.6. Assuming statistical isotropy, the convergence perturbation estimated from 11 observed quadruple lens systems has a positive correlation with the source redshift zS, which is much stronger than that with the lens redshift zL. This feature also supports that the flux ratio anomaly is caused mainly by line-of-sight structures rather than subhaloes. We also discuss a possible imprint of line-of-sight structures in the demagnification of minimum images due to locally underdense structures in the line of sight.

  18. On the Origin of Flux Ratio Anomaly in Quadruple Lens Systems

    CERN Document Server

    Inoue, Kaiki Taro

    2016-01-01

    We explore the origin of flux ratio anomaly in quadruple lens systems. Using a semi-analytic method based on $N$-body simulations, we estimate the effect of possible magnification perturbation caused by subhaloes with a mass scale of <~ $ 10^9\\,h^{-1} \\textrm{M}_\\odot$ in lensing galaxy haloes. Taking into account astrometric shifts by perturbers, we find that the expected change to the flux ratios per a multiply lensed image is just a few percent and the mean of the expected convergence perturbation at the effective Einstein radius of the lensing galaxy halo is $\\langle \\delta \\kappa_{\\textrm{sub}} \\rangle = 0.003$, corresponding to the mean of the ratio of a projected dark matter mass fraction in subhaloes $\\langle f_{\\textrm{sub}} \\rangle = 0.006$ for observed 11 quadruple lens systems. In contrast, the expected change to the flux ratio caused by line-of-sight structures in intergalactic spaces is typically ~10 percent and the mean of the convergence perturbation is $\\langle |\\delta \\kappa_{\\textrm{los}...

  19. Direct numerical simulation of turbulent heat transfer in annuli: Effect of heat flux ratio

    Energy Technology Data Exchange (ETDEWEB)

    Ould-Rouiss, M. [Universite Paris-Est, Laboratoire de Modlisation et Simulation Multi Echelle (MSME FRE-CNRS 3160), 5 Bvd Descartes, Champs-sur-Marne, F-77454 Marne-la-Vallee Cedex 2 (France)], E-mail: ould@univ-mlv.fr; Redjem-Saad, L.; Lauriat, G. [Universite Paris-Est, Laboratoire de Modlisation et Simulation Multi Echelle (MSME FRE-CNRS 3160), 5 Bvd Descartes, Champs-sur-Marne, F-77454 Marne-la-Vallee Cedex 2 (France)

    2009-08-15

    Fully developed turbulent flow and heat transfer in a concentric annular duct is investigated for the first time by using a direct numerical simulation (DNS) with isoflux conditions imposed at both walls. The Reynolds number based on the half-width between inner and outer walls, {delta}=(r{sub 2}-r{sub 1})/2, and the laminar maximum velocity is Re{sub {delta}}=3500. A Prandtl number Pr=0.71 and a radius ratio r*=0.1 were retained. The main objective of this work is to examine the effect of the heat flux density ratio, q*=q{sub 1}/q{sub 2}, on different thermal statistics (mean temperature profiles, root mean square (rms) of temperature fluctuations, turbulent heat fluxes, heat transfer, etc.). To validate the present DNS calculations, predictions of the flow and thermal fields with q*=1 are compared to results recently reported in the archival literature. A good agreement with available DNS data is shown. The effect of heat flux ratio q* on turbulent thermal statistics in annular duct with arbitrarily prescribed heat flux is discussed then. This investigation highlights that heat flux ratio has a marked influence on the thermal field. When q* varies from 0 to 0.01, the rms of temperature fluctuations and the turbulent heat fluxes are more intense near the outer wall while changes in q* from 1 to 100, lead to opposite trends.

  20. Evaluation of design limit critical heat flux ratio for the HANARO core

    International Nuclear Information System (INIS)

    Various design variables of HANARO were confirmed and measured through the commissioning and reactor operation. In addition, fuel assembly was modified and analysis model was improved. Hence, it is necessary to statistically re-evaluate the limit critical heat flux ratio as the thermal-hydraulic design parameter of the HANARO core. To evaluate the uncertainty in the design parameter, the uncertainties of all design variables related to the design parameter were identified and their sensitivity values were derived. A subchannel analysis code MATRAh was used to calculate the sensitivity and all power distributions from the present operating core to the estimated equilibrium core were taken into account to get conservative results. As evaluation results, the design limit CHFR for 36 and 18 element fuel assembly were determined as 1.82 and 1.77 respectively

  1. Monte Carlo simulation of V/III flux ratio influence on GaAs island nucleation during MBE

    Science.gov (United States)

    Ageev, O. A.; Solodovnik, M. S.; Balakirev, S. V.; Mikhaylin, I. A.

    2016-02-01

    The kinetic Monte Carlo simulation of GaAs/GaAs(001) molecular beam epitaxial growth considering V/III flux ratio influence on nucleating island characteristics is presented. It is shown that the island density increases with the surface coverage increase and reaches saturation after deposition of ∼0.1 monolayer of GaAs. The increase of V/III flux ratio from 3 to 40 leads to the increase of the island density from 1.9-1012 to 2.6-1012 cm-2. At the same time the average size decreases from 4.4 to 4.1 nm. The island size distribution function narrows with V/III flux ratio increase. This is attributed to the shortage of gallium atoms in comparison with deposited arsenic molecules that prevents large island formation and leads to the dramatic growth of little island concentration. The simulation demonstrates good agreement with experimental results.

  2. Measuring Methane Emissions from Industrial and Waste Processing Sites Using the Dual Tracer Flux Ratio Method

    Science.gov (United States)

    Herndon, S.; Floerchinger, C.; Roscioli, J. R.; Yacovitch, T.; Franklin, J. P.; Shorter, J. H.; Kolb, C. E.; Subramanian, R.; Robinson, A. L.; Molina, L. T.; Allen, D.

    2013-12-01

    In order to directly quantify facility scale methane emissions during recent multi-state measurement campaigns we have deployed novel tracer release emission characterization approaches to investigate a wide variety of facility types. The development and application of a dual tracer flux ratio methodology will be discussed. Using known release rates of two (or more) inert tracer species, downwind methane plume measurements can be used to quantify and evaluate the uncertainty in known releases and unknown emissions of methane. Results from experiments designed to challenge the experimental methodology will be presented, which determined that for downwind sampling distances in excess of ~200 m, the dual tracer release method is quite robust (emission rate error) under many atmospheric conditions and landscape variations. At downwind distances less than ~200 m, the assumption of equivalent dispersion between spatially separated release points can break down. For some facilities, this can be used to distinguish and estimate the magnitude of methane emissions taking place at different spatial points within the facility. Measured emissions for selected facilities will be presented and, where possible, the accurate quantification of the episodic releases during specific activities, as well as continuous fugitive emissions are identified and will be discussed . Collaboration with on-site operators allows these measurements to inform the design and implementation of effective mitigation strategies.

  3. Genome-scale modeling using flux ratio constraints to enable metabolic engineering of clostridial metabolism in silico

    Directory of Open Access Journals (Sweden)

    McAnulty Michael J

    2012-05-01

    Full Text Available Abstract Background Genome-scale metabolic networks and flux models are an effective platform for linking an organism genotype to its phenotype. However, few modeling approaches offer predictive capabilities to evaluate potential metabolic engineering strategies in silico. Results A new method called “flux balance analysis with flux ratios (FBrAtio” was developed in this research and applied to a new genome-scale model of Clostridium acetobutylicum ATCC 824 (iCAC490 that contains 707 metabolites and 794 reactions. FBrAtio was used to model wild-type metabolism and metabolically engineered strains of C. acetobutylicum where only flux ratio constraints and thermodynamic reversibility of reactions were required. The FBrAtio approach allowed solutions to be found through standard linear programming. Five flux ratio constraints were required to achieve a qualitative picture of wild-type metabolism for C. acetobutylicum for the production of: (i acetate, (ii lactate, (iii butyrate, (iv acetone, (v butanol, (vi ethanol, (vii CO2 and (viii H2. Results of this simulation study coincide with published experimental results and show the knockdown of the acetoacetyl-CoA transferase increases butanol to acetone selectivity, while the simultaneous over-expression of the aldehyde/alcohol dehydrogenase greatly increases ethanol production. Conclusions FBrAtio is a promising new method for constraining genome-scale models using internal flux ratios. The method was effective for modeling wild-type and engineered strains of C. acetobutylicum.

  4. Effects of Dark Matter Substructures on Gravitational Lensing: Results from the Aquarius Simulations

    CERN Document Server

    Xu, D D; Wang, J; Springel, V; Gao, L; White, S D M; Frenk, C S; Jenkins, A; Li, G; Navarro, J F

    2009-01-01

    We use high-resolution Aquarius simulations of Milky Way-sized haloes in the LCDM cosmology to study the effects of dark matter substructures on gravitational lensing. Each halo is resolved with ~ 10^8 particles (at a mass resolution ~ 10^3-4 M_sun/h) within its virial radius. Subhaloes with masses larger than 10^5 M_sun/h are well resolved, an improvement of at least two orders of magnitude over previous lensing studies. We incorporate a baryonic component modelled as a Hernquist profile and account for the response of the dark matter via adiabatic contraction. We focus on the "anomalous" flux ratio problem, in particular on the violation of the cusp-caustic relation due to substructures. We find that subhaloes with masses less than ~ 10^8 M_sun/h play an important role in causing flux anomalies; such low mass subhaloes have been unresolved in previous studies. There is large scatter in the predicted flux ratios between different haloes and between different projections of the same halo. In some cases, the f...

  5. Evidence of Decay of Flux Ratio of Fe to Fe–Ni Line Features with Electron Temperature in Solar Flares

    Indian Academy of Sciences (India)

    Rajmal Jain; Malini Aggarwal; Raghunandan Sharma

    2010-09-01

    We report observational evidence of the decay of the flux ratio of Fe to Fe–Ni line features as a function of plasma electron temperature in solar flares in comparison to that theoretically predicted by Phillips (2004). We present the study of spectral analysis of 14 flares observed by the Solar X-ray Spectrometer (SOXS) – Low Energy Detector (SLD) payload. The SLD payload employs the state-of-the-art solid state detectors, viz., Si PIN and Cadmium-Zinc-Telluride (CZT) devices. The sub-keV energy resolution of Si PIN detector allows us to study the Fe-line and Fe–Ni line features appearing at 6.7 and 8 keV, respectively, in greater detail. In order to best-fit the whole spectrum at one time in the desired energy range between 4 and 25 keV we considered Gaussian-line, the multi-thermal power-law and broken power-law functions. We found that the flux ratio of Fe to Fe–Ni line features decays with flare electron temperature by the asymptotic form of polynomial of inverse third order. The relative flux ratio is ∼ 30 at temperature 12 MK which drops to half, ∼ 15 at 20 MK, and at further higher temperatures it decreases smoothly reaching to ∼ 8 at ∼ 50 MK. The flux ratio, however, at a given flare plasma temperature, and its decrease with temperature is significantly lower than that predicted theoretically. We propose that the difference may be due to the consideration of higher densities of Fe and Fe–Ni lines in the theoretical model of Phillips (2004). We suggest revising the Fe and Fe–Ni line densities in the corona. The decay of flux ratio explains the variation of equivalent width and peak energy of these line features with temperature.

  6. Constraints on mixed dark matter from anomalous strong lens systems

    CERN Document Server

    Kamada, Ayuki; Takahashi, Tomo

    2016-01-01

    Recently it has been claimed that the warm dark matter (WDM) model cannot at the same time reproduce the observed Lyman-{\\alpha} forests in distant quasar spectra and solve the small-scale issues in the cold dark matter (CDM) model. As an alternative candidate, it was shown that the mixed dark matter (MDM) model that consists of WDM and CDM can satisfy the constraint from Lyman-{\\alpha} forests and account for the "missing satellite problem" as well as the reported 3.5 keV anomalous X-ray line. We investigate observational constraints on the MDM model using strong gravitational lenses. We first develop a fitting formula for the nonlinear power spectra in the MDM model by performing N-body simulations and estimate the expected perturbations caused by line-of-sight structures in four quadruply lensed quasars that show anomaly in the flux ratios. Our analysis indicates that the MDM model is compatible with the observed anomaly if the mass fraction of the warm component is smaller than 0.47 at the 95% confidence ...

  7. Anomalous Earth flybys of spacecraft

    Science.gov (United States)

    Wilhelm, Klaus; Dwivedi, Bhola N.

    2015-07-01

    A small deviation from the potential is expected for the gravitational interaction of extended bodies. It is explained as a consequence of a recently proposed gravitational impact model (Wilhelm et al. in Astrophys. Space Sci. 343:135-144, 2013) and has been applied to anomalous perihelion advances by Wilhelm and Dwivedi (New Astron. 31:51-55, 2014). The effect—an offset of the effective gravitational centre from the geometric centre of a spherical symmetric body—might also be responsible for the observed anomalous orbital energy gains and speed increases during Earth flybys of several spacecraft. However, close flybys would require detailed considerations of the orbit geometry. In this study, an attempt is made to explain the anomalous Earth flybys of the Galileo, NEAR Shoemaker and Rosetta spacecraft.

  8. Anomalous transport due to scale anomaly

    CERN Document Server

    Chernodub, M N

    2016-01-01

    We show that the scale anomaly in field theories leads to new anomalous transport effects that emerge in external electromagnetic field in inhomogeneous gravitational background. In inflating geometry the QED scale anomaly generates electric current which flows in opposite direction with respect to background electric field. In static spatially inhomogeneous gravitational background the dissipationless electric current flows transversely both to the magnetic field axis and to the gradient of the inhomogeneity. The anomalous currents are proportional to the beta function of the theory.

  9. Anomalous Magnetohydrodynamics

    OpenAIRE

    Giovannini, Massimo

    2013-01-01

    Anomalous symmetries induce currents which can be parallel rather than orthogonal to the hypermagnetic field. Building on the analogy with charged liquids at high magnetic Reynolds numbers, the persistence of anomalous currents is scrutinized for parametrically large conductivities when the plasma approximation is accurate. Different examples in globally neutral systems suggest that the magnetic configurations minimizing the energy density with the constraint that the helicity be conserved co...

  10. Gravitational anomaly and transport phenomena

    OpenAIRE

    Landsteiner, Karl; Megías Fernández, Eugenio; Pena-Benítez, Francisco

    2011-01-01

    Quantum anomalies give rise to new transport phenomena. In particular, a magnetic field can induce an anomalous current via the chiral magnetic effect and a vortex in the relativistic fluid can also induce a current via the chiral vortical effect. The related transport coefficients can be calculated via Kubo formulas. We evaluate the Kubo formula for the anomalous vortical conductivity at weak coupling and show that it receives contributions proportional to the gravitational anomaly coefficie...

  11. ALMA imprint of intergalactic dark structures in the gravitational lens SDP.81

    Science.gov (United States)

    Inoue, Kaiki Taro; Minezaki, Takeo; Matsushita, Satoki; Chiba, Masashi

    2016-04-01

    We present an analysis of the Atacama Large Millimeter/submillimeter Array long baseline science verification data of the gravitational lens system SDP.81. We fit the positions of the brightest clumps at redshift z = 3.042 and a possible active galactic nucleus component of the lensing galaxy at redshift z = 0.2999 in the band 7 continuum image using a canonical lens model, a singular isothermal ellipsoid plus an external shear. Then, we measure the ratio of fluxes in some apertures at the source plane where the lensed images are inversely mapped. We find that the aperture flux ratios of band 7 continuum image are perturbed by 10-20 per cent with a significance at 2 ˜ 3σ level. Moreover, we measure the astrometric shifts of multiply lensed images near the caustic using the CO(8-7) line. Using a lens model best fitted to the band 7 continuum image, we reconstruct the source image of the CO(8-7) line by taking linear combination of inverted quadruply lensed images. At the 50th channel (rest-frame velocity 28.6 km s-1) of the CO(8-7) line, we find an imprint of astrometric shifts of the order of 0.01 arcsec in the source image. Based on a semi-analytic calculation, we find that the observed anomalous flux ratios and the astrometric shifts can be explained by intergalactic dark structures in the line of sight. A compensated homogeneous spherical clump with a mean surface mass density of the order of 108 M⊙ h-1 arcsec-2 can explain the observed anomaly and astrometric shifts simultaneously.

  12. The X-ray to [Ne V]3426 flux ratio: discovering heavily obscured AGN in the distant Universe

    CERN Document Server

    Gilli, R; Mignoli, M; Iwasawa, K; Comastri, A; Zamorani, G

    2010-01-01

    We investigate the possibility of using the ratio between the 2-10 keV flux and the [Ne V]3426 emission line flux (X/NeV) as a diagnostic diagram to discover heavily obscured, possibly Compton-Thick Active Galactic Nuclei (AGN) up to z~1.5. First, we calibrate a relation between X/NeV and the cold absorbing column density N_H using a sample of 74 bright, nearby Seyferts with both X-ray and [Ne V] data available in the literature. Similarly to what is found for the X-ray to [O III]5007 flux ratio (X/OIII), we found that the X/NeV ratio decreases towards large column densities. Essentially all local Seyferts with X/NeV values below 15 are found to be Compton-Thick objects. Second, we apply this diagnostic diagram to different samples of distant obscured and unobscured QSOs in the SDSS: blue, unobscured, type-1 QSOs in the redshift range z=[0.1-1.5] show X/NeV values typical of unobscured Seyfert 1s in the local Universe. Conversely, SDSS type-2 QSOs at z~0.5 classified either as Compton-Thick or Compton-Thin on...

  13. Exploring the Active Galactic Nuclei population with extreme X-ray to optical flux ratios (Fx/Fo >50)

    CERN Document Server

    Della Ceca, R; Caccianiga, A; Severgnini, P; Ballo, L; Braito, V; Corral, A; Del Moro, A; Mateos, S; Ruiz, A; Watson, M G

    2015-01-01

    The cosmic history of the growth of supermassive black holes in galactic centers parallels that of star-formation in the Universe. However, an important fraction of this growth occurs inconspicuously in obscured objects, where ultraviolet/optical/near-infrared emission is heavily obscured by dust. Since the X-ray flux is less attenuated, a high X-ray-to-optical flux ratio (Fx/Fo) is expected to be an efficient tool to find out these obscured accreting sources. We explore here via optical spectroscopy, X-ray spectroscopy and infrared photometry the most extreme cases of this population (those with Fx/Fo >50, EXO50 sources hereafter), using a well defined sample of seven X-ray sources extracted from the 2XMM catalogue. Five EXO50 sources (about 70 percent of the sample) in the bright flux regime explored by our survey (f(2-10 keV) > 1.5E-13 cgs) are associated with obscured AGN (Nh > 1.0E22 cm-2), spanning a redshift range between 0.75 and 1 and characterised by 2-10 keV intrinsic luminosities in the QSO regime...

  14. Anomalous transport due to scale anomaly

    OpenAIRE

    Chernodub, M.N.

    2016-01-01

    We show that the scale anomaly in field theories leads to new anomalous transport effects that emerge in external electromagnetic field in inhomogeneous gravitational background. In inflating geometry the QED scale anomaly generates electric current which flows in opposite direction with respect to background electric field. In static spatially inhomogeneous gravitational background the dissipationless electric current flows transversely both to the magnetic field axis and to the gradient of ...

  15. Alkalinity to calcium flux ratios for corals and coral reef communities: variances between isolated and community conditions

    Directory of Open Access Journals (Sweden)

    Liana J.A. Murillo

    2014-02-01

    Full Text Available Calcification in reef corals and coral reefs is widely measured using the alkalinity depletion method which is based on the fact that two protons are produced for every mole of CaCO3 precipitated. This assumption was tested by measuring the total alkalinity (TA flux and Ca2+ flux of isolated components (corals, alga, sediment and plankton in reference to that of a mixed-community. Experiments were conducted in a flume under natural conditions of sunlight, nutrients, plankton and organic matter. A realistic hydrodynamic regime was provided. Groups of corals were run separately and in conjunction with the other reef components in a mixed-community. The TA flux to Ca2+ flux ratio (ΔTA: ΔCa2+ was consistently higher in the coral-only run (2.06 ± 0.19 than in the mixed-community run (1.60 ± 0.14, p-value = 0.011. The pH was higher and more stable in the mixed-community run (7.94 ± 0.03 vs. 7.52 ± 0.07, p-value = 3 × 10−5. Aragonite saturation state (Ωarag was also higher in the mixed-community run (2.51 ± 0.2 vs. 1.12 ± 0.14, p-value = 2 × 10−6. The sediment-only run revealed that sediment is the source of TA that can account for the lower ΔTA: ΔCa2+ ratio in the mixed-community run. The macroalgae-only run showed that algae were responsible for the increased pH in the mixed-community run. Corals growing in a mixed-community will experience an environment that is more favorable to calcification (higher daytime pH due to algae photosynthesis, additional TA and inorganic carbon from sediments, higher Ωarag. A paradox is that the alkalinity depletion method will yield a lower net calcification for a mixed-community versus a coral-only community due to TA recycling, even though the corals may be calcifying at a higher rate due to a more optimal environment.

  16. Increased bismuth concentration in MBE GaAs{sub 1−x}Bi{sub x} films by oscillating III/V flux ratio during growth

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Adam W., E-mail: awood4@wisc.edu; Babcock, Susan E. [Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States); Li, Jincheng; Brown, April S. [Electrical and Computer Engineering, Duke University, Durham, North Carolina 27707 (United States)

    2015-05-15

    The authors have examined bismuth concentration profiles in GaAs{sub 1−x}Bi{sub x} films grown by molecular beam epitaxy using high angle annular dark field imaging (Z-contrast imaging) in an aberration-corrected scanning transmission electron microscope in conjunction with x-ray diffraction. Samples were grown with a gradient in each of the component fluxes, and therefore, the III/V ratio across the substrate. Rotating the sample during growth exposed the growth surface to an oscillating III/V flux ratio. Sinusoidal [Bi] profiles resulted in the growth direction, the wavelength and number of which were consistent with the growth rate and the rate of substrate rotation. However, the magnitude of [Bi] in the observed fluctuations was greater than the maximum [Bi] achieved using the same Bi flux and Ga/As flux ratios in steady-state conditions on a stationary substrate, suggesting that varying the III/V flux ratio during growth promotes the incorporation of Bi in GaAs{sub 1−x}Bi{sub x} films. A proposed qualitative model for how this enhancement might occur hypothesizes a critical role for alternating growth and shrinkage of Ga-Bi predroplet clusters on the surface as the growing material is rotated through Ga-rich and As-rich flux compositions.

  17. Gravitational Waves from Gravitational Collapse

    OpenAIRE

    New Kimberly C.B.

    2002-01-01

    Gravitational wave emission from the gravitational collapse of massive stars has been studied for more than three decades. Current state of the art numerical investigations of collapse include those that use progenitors with realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non--axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational colla...

  18. Gravitational lensing by gravitational waves

    OpenAIRE

    Bisnovatyi-Kogan, G. S.; Tsupko, O. Yu.

    2008-01-01

    Gravitational lensing by gravitational wave is considered. We notice that although final and initial direction of photons coincide, displacement between final and initial trajectories occurs. This displacement is calculated analytically for the plane gravitational wave pulse. Estimations for observations are discussed.

  19. Predicting Intrinsic mid-IR to optical flux ratios for galaxies of different types using Spectral Synthesis Models of Composite Stellar Populations

    Science.gov (United States)

    Kim, Duho; Jansen, Rolf A.; Windhorst, Rogier A.

    2016-01-01

    We analyze the intrinsic flux ratios of simple and composite stellar populations for various visible--near-infrared filters with respect to ˜3.5μm (L-band), and their dependence on metallicity, star-formation history, and effective mean age. This study is motivated by the fact that light from galaxies is reddened and attenuated by dust via scattering and absorption, where different sightlines across the face of a galaxy suffer various amounts of extinction. Ignoring the effects of this extinction could lead one to infer lower stellar mass, and SFR, or higher metallicity. Tamura et al. (2009) developed an approximate method, dubbed the "βV" method, which corrects for dust-extinction on a pixel-by-pixel basis, by comparing the observed flux ratio and empirical estimate of the intrinsic flux ratio of optical and ˜3.5μm broadband data. Here, we aim to validate and test the limits of the βV method for various filters spanning the visible through near-infrared wavelength range. Through extensive modeling, we test their assumptions for the intrinsic flux ratios for a wide variety of simple and composite stellar populations. We build spectral energy distributions (SEDs) of simple stellar populations (SSPs), by adopting Starburst99 and BC03 models for young (100Myr) stellar populations, respectively, and linear combinations of these for intermediate ages. We then construct composite stellar population (CSP) SEDs by combining SSP SEDs for various realistic star-formation histories (SFHs). We convolve filter response curves of visible--near-infrared filters for HST imaging surveys and mid-infrared filters in current (WISE, Spitzer/IRAC) and near-future use (JWST/NIRCam) with each model SED, to obtain intrinsic flux ratios (βλ,0). We find that βNIR,0 is only varying slightly as a function of metallicity but is insensitive to SFH or redshift (z≤2). We also find a narrow range of βV,0 (0.7+0.05-0.08) for early Hubble type galaxies (E and S0) using SEDs of randomly

  20. Natural wormholes as gravitational lenses

    CERN Document Server

    Cramer, J G; Morris, M S; Visser, M; Benford, G; Landis, G A; Cramer, John G; Forward, Robert L; Morris, Michael S; Visser, Matt; Benford, Gregory; Landis, Geoffrey A

    1995-01-01

    Visser has suggested traversable 3-dimensional wormholes that could plausibly form naturally during Big Bang inflation. A wormhole mouth embedded in high mass density might accrete mass, giving the other mouth a net *negative* mass of unusual gravitational properties. The lensing of such a gravitationally negative anomalous compact halo object (GNACHO) will enhance background stars with a time profile that is observable and qualitatively different from that recently observed for massive compact halo objects (MACHOs) of positive mass. We recommend that MACHO search data be analyzed for GNACHOs.

  1. Fluid/Gravity Correspondence, Second Order Transport and Gravitational Anomaly*,**

    Directory of Open Access Journals (Sweden)

    Megías Eugenio

    2014-03-01

    Full Text Available We study the transport properties of a relativistic fluid affected by chiral and gauge-gravitational anomalies. The computation is performed in the framework of the fluid/gravity correspondence for a 5 dim holographic model with Chern-Simons terms in the action. We find new anomalous and non anomalous transport coefficients, as well as new contributions to the existing ones coming from the mixed gauge-gravitational anomaly. Consequences for the shear waves dispersion relation are analyzed.

  2. Gravitation research

    Science.gov (United States)

    Weiss, R.; Muehlner, D. J.; Benford, R. L.; Owens, D. K.; Pierre, N. A.; Rosenbluh, M.

    1972-01-01

    Balloon measurements were made of the far infrared background radiation. The radiometer used and its calibration are discussed. An electromagnetically coupled broadband gravitational antenna is also considered. The proposed antenna design and noise sources in the antenna are reviewed. A comparison is made between interferometric broadband and resonant bar antennas for the detection of gravitational wave pulses.

  3. Gravitational Waves

    OpenAIRE

    Schutz, Bernard F.

    1990-01-01

    In 1989 four groups around the world proposed the construction of large-scale laser interferometric gravitational wave detectors. The author reviews the design of these detectors, the problems of analysing their data, and the theory of the sources of the gravitational waves that they are designed to detect.

  4. Analysis of the Intrinsic Mid-Infrared L-band to Visible--Near-Infrared Flux Ratios in Spectral Synthesis Models of Composite Stellar Populations

    CERN Document Server

    Kim, Duho; Windhorst, Rogier A

    2016-01-01

    We analyze the intrinsic flux ratios of various visible--near-infrared filters with respect to 3.5micron for simple and composite stellar populations, and their dependence on age, metallicity and star formation history. UV/optical light from stars is reddened and attenuated by dust, where different sightlines across a galaxy suffer varying amounts of extinction. Tamura et al. (2009) developed an approximate method to correct for dust extinction on a pixel-by-pixel basis, dubbed the "beta_V" method, by comparing the observed flux ratio to an empirical estimate of the intrinsic ratio of visible and ~3.5micron data. Through extensive modeling, we aim to validate the "beta_V" method for various filters spanning the visible through near-infrared wavelength range, for a wide variety of simple and composite stellar populations. Combining Starburst99 and BC03 models, we built spectral energy distributions (SEDs) of simple (SSP) and composite (CSP) stellar populations for various realistic star formation histories (SF...

  5. Discrete fields and the Pioneer anomalous acceleration

    CERN Document Server

    De Souza, M M

    2001-01-01

    The dominant contributions from a discrete gravitational interaction produce the standard potential as an effective continuous field. The sub-dominant contributions are, in a first approximation, linear on n, the accumulated number of (discrete) interaction events along the test-body trajectory. For a nearly radial trajectory n is proportional to the traversed distance and its effects may have been observed as the Pioneer anomalous constant radial acceleration, which cannot be observed on the nearly circular planetary orbits.

  6. Gravitating Hopfions

    Energy Technology Data Exchange (ETDEWEB)

    Shnir, Ya. M., E-mail: shnir@theor.jinr.ru [Joint Institute for Nuclear Research (Russian Federation)

    2015-12-15

    We construct solutions of the 3 + 1 dimensional Faddeev–Skyrme model coupled to Einstein gravity. The solutions are static and asymptotically flat. They are characterized by a topological Hopf number. We investigate the dependence of the ADM masses of gravitating Hopfions on the gravitational coupling. When gravity is coupled to flat space solutions, a branch of gravitating Hopfion solutions arises and merges at a maximal value of the coupling constant with a second branch of solutions. This upper branch has no flat space limit. Instead, in the limit of a vanishing coupling constant, it connects to either the Bartnik–McKinnon or a generalized Bartnik–McKinnon solution. We further find that in the strong-coupling limit, there is no difference between the gravitating solitons of the Skyrme model and the Faddeev–Skyrme model.

  7. Hubble red shift and the anomalous acceleration of Pioneer 10 and 11

    OpenAIRE

    Trencevski, Kostadin

    2004-01-01

    It is introduced a hypothesis that the gravitational potential in the universe changes linearly with the time. This enables to explain the Hubble red shift and the anomalous acceleration of Pioneer 10 and 11.

  8. Gravitational mirages

    International Nuclear Information System (INIS)

    As predicted by general relativity, gravitation curves light rays, an effect which produces actual gravitational mirages: the image of a distant source is distorted, amplified, and multiplied by the mass of a galaxy close to the path of the rays. Astronomers have already detected several such configurations in the form of 'double' or 'multiple' quasars. They are using these to gain access to a range of information on galaxies, quasars and even the geometry of the Universe. (author)

  9. Holographic Gravitational Anomaly in First and Second Order Hydrodynamics

    CERN Document Server

    Megias, Eugenio

    2013-01-01

    We compute, in the framework of the fluid/gravity correspondence, the transport coefficients of a relativistic fluid affected by chiral and gauge-gravitational anomalies, including external electromagnetic fields. The computation is performed at first and second order in the hydrodynamical expansion. We use a 5-dim holographic model with pure gauge and mixed gauge-gravitational Chern-Simons terms in the action. We reproduce at first order previous results on the anomaly induced current of a magnetic field and a vortex in a relativistic fluid, and compute at second order the anomalous and non anomalous transport coefficients by using a Weyl covariant formalism. We find a dissipative and anomalous correction to the chiral magnetic conductivity due to the time dependence of the magnetic field. We also find a new contribution from the mixed gauge-gravitational anomaly to the shear waves dispersion relation. The role played by the chiral and gravitational anomalies in other transport coefficients is discussed.

  10. Gravitational Waves from Gravitational Collapse

    Directory of Open Access Journals (Sweden)

    Chris L. Fryer

    2011-01-01

    Full Text Available Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  11. Gravitational waves from gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Fryer, Christopher L [Los Alamos National Laboratory; New, Kimberly C [Los Alamos National Laboratory

    2008-01-01

    Gravitational wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  12. Gravitational analogue of the Witten effect

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O. (International Centre for Theoretical Physics, Trieste (Italy))

    1985-07-22

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP violation, the Witten effect (a shift in the electric charge of a magnetic monopole due to CP non-conservation) is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a thetaR tildeR term in the lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed.

  13. The gravitational analogue of the Witten effect

    International Nuclear Information System (INIS)

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP violation, the Witten effect (a shift in the electric charge of a magnetic monopole due to CP non-conservation) is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a thetaR tildeR term in the lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed. (orig.)

  14. The gravitational analogue of the Witten effect

    International Nuclear Information System (INIS)

    In the presence of massive fermions, and assuming a non-vanishing theta-parameter as the only source of CP-violation, the Witten effect [a shift in the electric charge of a magnetic monopole due to CP-non-conservation] is shown to follow from an anomalous chiral commutator. Next, given the gravitational contribution to the chiral anomaly, the corresponding anomalous commutator for Dirac fermion currents in a gravitational background is derived. From that, we infer the equivalence of a theta R-tilde R term in the Lagrangian to a shift in the mass parameter of the NUT metric, in proportion to theta. This is interpreted as the gravitational analogue of the Witten effect. Its relevance to certain Kaluza-Klein monopoles is briefly discussed. (author)

  15. A New Channel for Detecting Dark Matter Substructure in Galaxies: Gravitational Lens Time Delays

    CERN Document Server

    Keeton, Charles R

    2008-01-01

    We show that dark matter substructure in galaxy-scale halos perturbs the time delays between images in strong gravitational lens systems. The variance of the effect depends on the subhalo mass function, scaling as the product of the substructure mass fraction and a characteristic mass of subhalos (namely /). Time delay perturbations therefore complement gravitational lens flux ratio anomalies and astrometric perturbations by measuring a different moment of the subhalo mass function. Unlike flux ratio anomalies, "time delay millilensing" is unaffected by dust extinction or stellar microlensing in the lens galaxy. Furthermore, we show that time delay ratios are immune to the radial profile degeneracy that usually plagues lens modeling. We lay out a mathematical theory of time delay perturbations and find it to be tractable and attractive. We predict that in "cusp" lenses with close triplets of images, substructure may change the arrival-time order of the images (compared with smooth models). We discuss the poss...

  16. Using gravitational lenses to detect gravitational waves

    OpenAIRE

    Allen, B.

    1990-01-01

    Gravitational lenses could be used to detect gravitational waves, because a gravitational wave affects the travel-time of a light ray. In a gravitational lens, this effect produces time-delays between the different images. Thus the bending of light, which was the first experimental confirmation of Einstein's theory, can be used to search for gravitational waves, which are the most poorly confirmed aspect of that same theory. Applying this method to the gravitational lens 0957+561 gives new up...

  17. Gravitational Horizon(3)

    Science.gov (United States)

    Yang, Chao Yuan

    2012-05-01

    Anomalous decelerations of spacecraft Pioneer-10,11,etc could be interpreted as signal delay effect between speed of gravity and that of light as reflected in virtual scale, similar to covarying virtual scale effect in relative motion (http://arxiv.org/html/math-ph/0001019v5).A finite speed of gravity faster than light could be inferred (http://arXiv.org/html/physics/0001034v2). Measurements of gravitational variations by paraconical pendulum during a total solar eclipse infer the same(http://arXiv.org/html/physics/0001034v9). A finite Superluminal speed of gravity is the necessary condition to imply that there exists gravitational horizon (GH). Such "GH" of our Universe would stretch far beyond the cosmic event horizon of light. Dark energy may be owing to mutually interactive gravitational horizons of cousin universes. Sufficient condition for the conjecture is that the dark energy would be increasing with age of our Universe since accelerated expansion started about 5 Gyr ago, since more and more arrivals of "GH" of distant cousin universes would interact with "GH" of our Universe. The history of dark energy variations between then and now would be desirable(http://arXiv.org/html/physics/0001034). In "GH" conjecture, the neighborhood of cousin universes would be likely boundless in 4D-space-time without begining or end. The dark energy would keep all universes in continually accelerated expansion to eventual fragmentation. Fragments would crash and merge into bangs, big or small, to form another generation of cousin universes. These scenarios might offer a clue to what was before the big bang.

  18. About Gravitation

    OpenAIRE

    B. G. Sidharth

    2004-01-01

    We consider different deductions of the mysterious Weinberg formula and show that this leads us back to the model of fluctuational cosmology which correctly predicted in advance, dark energy driven, accelerating universe with a small cosmological constant. All this also provides us with an interpretation of Gravitation as the distributional effect of the residual energy of the universe.

  19. Gravitational waves

    CERN Document Server

    Ciufolini, I; Moschella, U; Fre, P

    2001-01-01

    Gravitational waves (GWs) are a hot topic and promise to play a central role in astrophysics, cosmology, and theoretical physics. Technological developments have led us to the brink of their direct observation, which could become a reality in the coming years. The direct observation of GWs will open an entirely new field: GW astronomy. This is expected to bring a revolution in our knowledge of the universe by allowing the observation of previously unseen phenomena, such as the coalescence of compact objects (neutron stars and black holes), the fall of stars into supermassive black holes, stellar core collapses, big-bang relics, and the new and unexpected.With a wide range of contributions by leading scientists in the field, Gravitational Waves covers topics such as the basics of GWs, various advanced topics, GW detectors, astrophysics of GW sources, numerical applications, and several recent theoretical developments. The material is written at a level suitable for postgraduate students entering the field.

  20. Gravitational waves

    CERN Document Server

    Thorne, K S

    1995-01-01

    This article reviews current efforts and plans for gravitational-wave detection, the gravitational-wave sources that might be detected, and the information that the detectors might extract from the observed waves. Special attention is paid to (i) the LIGO/VIRGO network of earth-based, kilometer-scale laser interferometers, which is now under construction and will operate in the high-frequency band (1 to 10^4 Hz), and (ii) a proposed 5-million-kilometer-long Laser Interferometer Space Antenna (LISA), which would fly in heliocentric orbit and operate in the low-frequency band (10^{-4} to 1 Hz). LISA would extend the LIGO/VIRGO studies of stellar-mass (M\\sim2 to 300 M_\\odot) black holes into the domain of the massive black holes (M\\sim1000 to 10^8M_\\odot) that inhabit galactic nuclei and quasars.

  1. Relativistic Transverse Gravitational Redshift

    Science.gov (United States)

    Mayer, A. F.

    2012-12-01

    The parametrized post-Newtonian (PPN) formalism is a tool for quantitative analysis of the weak gravitational field based on the field equations of general relativity. This formalism and its ten parameters provide the practical theoretical foundation for the evaluation of empirical data produced by space-based missions designed to map and better understand the gravitational field (e.g., GRAIL, GRACE, GOCE). Accordingly, mission data is interpreted in the context of the canonical PPN formalism; unexpected, anomalous data are explained as similarly unexpected but apparently real physical phenomena, which may be characterized as ``gravitational anomalies," or by various sources contributing to the total error budget. Another possibility, which is typically not considered, is a small modeling error in canonical general relativity. The concept of the idealized point-mass spherical equipotential surface, which originates with Newton's law of gravity, is preserved in Einstein's synthesis of special relativity with accelerated reference frames in the form of the field equations. It was not previously realized that the fundamental principles of relativity invalidate this concept and with it the idea that the gravitational field is conservative (i.e., zero net work is done on any closed path). The ideal radial free fall of a material body from arbitrarily-large range to a point on such an equipotential surface (S) determines a unique escape-velocity vector of magnitude v collinear to the acceleration vector of magnitude g at this point. For two such points on S separated by angle dφ , the Equivalence Principle implies distinct reference frames experiencing inertial acceleration of identical magnitude g in different directions in space. The complete equivalence of these inertially-accelerated frames to their analogous frames at rest on S requires evaluation at instantaneous velocity v relative to a local inertial observer. Because these velocity vectors are not parallel, a

  2. Gravitational anomaly and hydrodynamics in AdS/CFT

    International Nuclear Information System (INIS)

    Using a holographic model with a pure gauge and mixed gauge-gravitational Chern-Simons terms in the action, we analyze the anomalous induced current of a vortex in the relativistic fluid via the chiral vortical effect, which is analogous to the anomalous current induced by a magnetic field via the chiral magnetic effect. The gravitational anomaly gives rise to an anomalous vortical effect even for an uncharged fluid characterized by a term proportional to T2. The numerical value of this term is not renormalized compared to the weak coupling result [1]. We also address on a general formalism to unify the two inequivalent implementations to the chemical potential for an anomalous symmetry presented in [2]. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. The effective inertial acceleration due to oscillations of the gravitational potential: footprints in the solar system

    CERN Document Server

    Khokhlov, D L

    2003-01-01

    The conjecture is considered that every body induces the wave field which imposes oscillations on the gravitational potential of a body. The function for oscillations is chosen to prevent the gravitational collapse of the matter at the nucleus energy density. The conjecture leads to modification of the Newtonian gravity. The effect is too small to be seen in observations in the solar system. Oscillations of the gravitational potential of a body produce effective inertial outward acceleration for a particle orbiting around the body. Footprints of the effective inertial acceleration due to oscillations of the gravitational potentials of the Sun and Earth are investigated. The conjecture allows to explain the anomalous shift of the perihelion of Mercury and Icarus, the anomalous shift of the perigee of LAGEOS II, the anomalous acceleration acting on Pioneer 10, 11, the anomalous increase in the lunar semi-major axis. The advance of the Keplerian orbit for Earth, Jupiter, Neptune, Uranus caused by the effective i...

  4. Anomalous redshifts of quasi-stellar objects

    International Nuclear Information System (INIS)

    This paper is based on the assumption that the observational evidence to date does point to the possibility that high-redshift quasars are physically associated with low-redshift galaxies. It is first argued that the excess (or anomalous) redshifts of the quasars in such associations are unlikely to be either of Doppler or of gravitational origin. A new source for this excess redshift was suggested by Narlikar on the basis of the Hoyle-Narlikar theory of gravitation which is based on Mach's principle. This idea is applied to the hypothesis that quasars may have been ejected from galactic nuclei. The dynamics of such an ejection and its observable consequences are discussed. In particular, it is shown that quasar alignments and redshift bunching which have been observed recently can be understood within the framework of this theory. Further test of this hypothesis are discussed

  5. GRAVITATIONAL RADIATION

    Directory of Open Access Journals (Sweden)

    Metin SALTIK

    1996-03-01

    Full Text Available According to classical electromagnetic theory, an accelerated charge or system of charges radiates electromagnetic waves. In a radio transmitter antenna charges are accelerated along the antenna and release electromagnetic waves, which is radiated at the velocity of light in the surrounding medium. All of the radio transmitters work on this principle today. In this study an analogy is established between the principles by which accelerated charge systems markes radiation and the accelerated mass system, and the systems cousing gravitational radiation are investigated.

  6. Dirac particle spin in strong gravitational fields

    Science.gov (United States)

    Obukhov, Yu. N.; Silenko, A. J.; Teryaev, O. V.

    2014-01-01

    Dynamics of the Dirac particle spin in general strong gravitational fields is discussed. The Hermitian Dirac Hamiltonian is derived and transformed to the Foldy-Wouthuysen (FW) representation for an arbitrary metric. The quantum mechanical equations of spin motion are found. These equations agree with corresponding classical ones. The new restriction on the anomalous gravitomagnetic moment (AGM) by the reinterpretation of Lorentz invariance tests is obtained.

  7. Anomalous Chiral Superfluidity

    OpenAIRE

    Lublinsky, Michael(Physics Department, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel); Zahed, Ismail

    2009-01-01

    We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavour anomalies as an effective theory for flavored chiral phonons in a chiral superfluid with the gauged Wess-Zumino-Witten term. In the mean-field (leading tadpole) approximation the anomalous Cartan currents and the energy momentum tensor take the form of constitutive currents in the chiral superfluid state. The pertinence of higher order corrections and the Adler-Bardeen theorem is ...

  8. Hydrodynamic Waves in an Anomalous Charged Fluid

    CERN Document Server

    Abbasi, Navid; Rezaei, Zahra

    2015-01-01

    We study the collective excitations in a relativistic fluid with an anomalous conserved charge. In $3+1$ dimensions, in addition to two ordinary sound modes we find two propagating modes in presence of an external magnetic field: one with a velocity proportional to the coefficient of gauge-gravitational anomaly coefficient and the other with a velocity which depends on both chiral anomaly and the gauge gravitational anomaly coefficients. While the former is the Chiral Alfv\\'en wave recently found in arXiv:1505.05444, the latter is a new type of collective excitations originated from the density fluctuations. We refer to these modes as the Type-M and Type-D chiral Alfv\\'en waves respectively. We show that the Type-M Chiral Alfv\\'en mode is split into two chiral Alfv\\'en modes when taking into account the effect of dissipation processes in the fluid. In 1+1 dimensions we find only one propagating mode associated with the anomalous effects. We explicitly compute the velocity of this wave and show that in contras...

  9. A possible explanation for the anomalous acceleration of Pioneer 10

    OpenAIRE

    Crawford, David F.

    1999-01-01

    The reported anomalous acceleration of the Pioneer 10 spacecraft of -8.5X10^{-10} m/s^2 (i.e. towards the sun) can be explained by a gravitational interaction on the S-band signals traveling between Pioneer 10 and the earth. The effect of this gravitational interaction is a frequency shift that is proportional to the distance and the square root of the density of the medium in which it travels. If changes in this frequency are interpreted as a Doppler shift the result is an apparent accelerat...

  10. Anomalous Higgs couplings

    CERN Document Server

    González-Garciá, M Concepción

    1999-01-01

    We review the effects of new effective interactions on Higgs-boson phenomenology. New physics in the electroweak bosonic sector is expected to induce additional interactions between the Higgs doublet field and the electroweak gauge bosons, leading to anomalous Higgs couplings as well as anomalous gauge-boson self-interactions. Using a linearly realized SU(2)/sub L/*U(1)/sub Y/ invariant effective Lagrangian to describe the bosonic sector of the Standard Model, we review the effects of the new effective interactions on the Higgs- boson production rates and decay modes. We summarize the results from searches for the new Higgs signatures induced by the anomalous interactions in order to constrain the scale of new physics, in particular at CERN LEP and Fermilab Tevatron colliders. (43 refs).

  11. Gravitational Superenergy Tensor

    OpenAIRE

    Mashhoon, Bahram; McClune, James C.; Quevedo, Hernando

    1996-01-01

    We provide a physical basis for the local gravitational superenergy tensor. Furthermore, our gravitoelectromagnetic deduction of the Bel-Debever-Robinson superenergy tensor permits the identification of the gravitational stress-energy tensor. This {\\it local} gravitational analog of the Maxwell stress-energy tensor is illustrated for a plane gravitational wave.

  12. A new gravitational lens from the MUSCLES survey: ULAS J082016.1 081216

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Neal; /Manchester U.; Ofek, Eran O.; /Caltech; Oguri, Masamune; /KIPAC, Menlo Park

    2009-06-19

    We present observations of a new double-image gravitational lens system, ULAS J082016.1+081216, of image separation 2.3 and high ({approx}6) flux ratio. The system is selected from the Sloan Digital Sky Survey spectroscopic quasar list using new high-quality images from the UKIRT Deep Sky Survey (UKIDSS). The lensed quasar has a source redshift of 2.024, and we identify the lens galaxy as a faint red object of redshift 0.803 {+-} 0.001. Three other objects from the UKIDSS survey, selected in the same way, were found not to be lens systems. Together with the earlier lens found using this method, the SDSS-UKIDSS lenses have the potential to significantly increase the number of quasar lenses found in SDSS, to extend the survey to higher flux ratios and lower separations, and to give greater completeness which is important for statistical purposes.

  13. A new gravitational lens from the MUSCLES survey: ULAS J082016.1+081216

    CERN Document Server

    Jackson, Neal; Oguri, Masamune

    2009-01-01

    We present observations of a new double-image gravitational lens system, ULAS J082016.1+081216, of image separation 2.3" and high (~6) flux ratio. The system is selected from the Sloan Digital Sky Survey spectroscopic quasar list using new high-quality images from the UKIRT Deep Sky Survey (UKIDSS). The lensed quasar has a source redshift of 2.024, and we identify the lens galaxy as a faint red object of redshift 0.803+/-0.001. Three other objects from the UKIDSS survey, selected in the same way, were found not to be lens systems. Together with the earlier lens found using this method, the SDSS-UKIDSS lenses have the potential to significantly increase the number of quasar lenses found in SDSS, to extend the survey to higher flux ratios and lower separations, and to give greater completeness which is important for statistical purposes.

  14. Source-position transformation -- an approximate invariance in strong gravitational lensing

    CERN Document Server

    Schneider, Peter

    2013-01-01

    The main obstacle for gravitational lensing to determine accurate masses of deflectors, or to determine precise estimates for the Hubble constant, is the degeneracy of lensing observables with respect to the mass-sheet transformation (MST). The MST is a global modification of the mass distribution which leaves all image positions, shapes and flux ratios invariant, but which changes the time delay. Here we show that another global transformation of lensing mass distributions exists which almost leaves image positions and flux ratios invariant, and of which the MST is a special case. Whereas for axi-symmetric lenses this source position transformation exactly reproduces all strong lensing observables, it does so only approximately for more general lens situations. We provide crude estimates for the accuracy with which the transformed mass distribution can reproduce the same image positions as the original lens model, and present an illustrative example of its performance. This new invariance transformation most...

  15. Anomalous law of cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lapas, Luciano C., E-mail: luciano.lapas@unila.edu.br [Universidade Federal da Integração Latino-Americana, Caixa Postal 2067, 85867-970 Foz do Iguaçu, Paraná (Brazil); Ferreira, Rogelma M. S., E-mail: rogelma.maria@gmail.com [Centro de Ciências Exatas e Tecnológicas, Universidade Federal do Recôncavo da Bahia, 44380-000 Cruz das Almas, Bahia (Brazil); Rubí, J. Miguel, E-mail: mrubi@ub.edu [Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona (Spain); Oliveira, Fernando A., E-mail: fernando.oliveira@pq.cnpq.br [Instituto de Física and Centro Internacional de Física da Matéria Condensada, Universidade de Brasília, Caixa Postal 04513, 70919-970 Brasília, Distrito Federal (Brazil)

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  16. Anomalous gauge boson interactions

    International Nuclear Information System (INIS)

    We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge-boson self interactions. If the energy scale of the new physics is ∼ 1 TeV, these low energy anomalous couplings are expected to be no larger than Ο(10-2). Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed

  17. Anomalous law of cooling

    International Nuclear Information System (INIS)

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics

  18. Anomalous law of cooling

    Science.gov (United States)

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-01

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  19. Anomalous pion decay revisited

    CERN Document Server

    Battistel, O A; Nemes, M C; Hiller, B

    1999-01-01

    An implicit four dimensional regularization is applied to calculate the axial-vector-vector anomalous amplitude. The present technique always complies with results of Dimensional Regularization and can be easily applied to processes involving odd numbers of $\\gamma_5$ matrices. This is illustrated explicitely in the example of this letter.

  20. Anomalous Hall effect

    Czech Academy of Sciences Publication Activity Database

    Nagaosa, N.; Sinova, Jairo; Onoda, S.; MacDonald, A. H.; Ong, N. P.

    2010-01-01

    Roč. 82, č. 2 (2010), s. 1539-1592. ISSN 0034-6861 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 51.695, year: 2010

  1. Gravitational lenses as long-baseline gravitational-wave detectors

    OpenAIRE

    Allen, B.

    1989-01-01

    Gravitational waves produce a time delay between the different images of a gravitational lens. The measurements of the time delay in the gravitational lens 0957±561 put new limits on the amplitude of low-frequency gravitational waves h

  2. On the gravitational scattering of gravitational waves

    International Nuclear Information System (INIS)

    We discuss the scattering of weak gravitational waves from a slowly rotating gravitational source, having mass M and angular momentum J-vector . We start considering the dynamics of a massless spin-2 field ϕμν propagating in the weak gravitational field of the source, writing down the Fierz–Pauli in the presence of a slightly curved background. We adopt a semiclassical framework, where the gravitational background is described as a classical external field; meanwhile, the spin-2 field is treated quantum mechanically. In the weak-coupling limit, in which the typical wavelength of ϕμν satisfies λϕ≫Rs (where Rs is the Schwarzschild radius of the source), we obtain the cross-section for the scattering process in the Born approximation. We also discuss helicity asymmetry, showing its relationship with the spin-2 field coupling to the derivatives of the background metric. We finally consider the transition to the case of gravitational wave scattering, showing that—under reasonable assumptions—gravitational waves are expected to follow the same behavior. Our results partly agree with those presented through the years by various authors. The present analysis suggests that the scattering of weak gravitational waves in the field of a macroscopic gravitational source still represents an interesting open issue for further careful investigation. (paper)

  3. Underdevelopment’s gravitation

    Directory of Open Access Journals (Sweden)

    Marin Dinu

    2013-09-01

    Full Text Available The energy necessary to escape the gravitational pull of underdevelopment and to enter an evolutional trajectory dependent on the gravitational pull of development is unintelligible in economic terms.

  4. Nonlocal Anomalous Hall Effect

    Science.gov (United States)

    Zhang, Steven S.-L.; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.

  5. Watching Gravitational Waves

    OpenAIRE

    Moortgat, Joachim

    2001-01-01

    In the vicinity of merging neutron strar binaries or supernova remnants, gravitational waves can interact with the prevailing strong magnetic fields. The resulting partial conversion of gravitational waves into electromagnetic (radio) waves might prove to be an indirect way of detecting gravitational waves from such sources. Another interesting interaction considered in this article is the excitation of magnetosonic plasma waves by a gravitational wave passing through the surrounding plasma. ...

  6. Gravitation in Material Media

    Science.gov (United States)

    Ridgely, Charles T.

    2011-01-01

    When two gravitating bodies reside in a material medium, Newton's law of universal gravitation must be modified to account for the presence of the medium. A modified expression of Newton's law is known in the literature, but lacks a clear connection with existing gravitational theory. Newton's law in the presence of a homogeneous material medium…

  7. Detection of gravitational radiation

    International Nuclear Information System (INIS)

    In this report the main contributions presented at the named symposium are collected. These concern astrophysical sources of gravitational radiation, ultracryogenic gravitational wave experiments, read out and data analysis of gravitational wave antennas, cryogenic aspects of large mass cooling to mK temperatures, and metallurgical and engineering aspects of large Cu structure manufacturing. (HSI)

  8. Detection of gravitational radiation

    Energy Technology Data Exchange (ETDEWEB)

    Holten, J.W. van [ed.

    1994-12-31

    In this report the main contributions presented at the named symposium are collected. These concern astrophysical sources of gravitational radiation, ultracryogenic gravitational wave experiments, read out and data analysis of gravitational wave antennas, cryogenic aspects of large mass cooling to mK temperatures, and metallurgical and engineering aspects of large Cu structure manufacturing. (HSI).

  9. Unparticles and anomalous dimensions in the cuprates

    Science.gov (United States)

    Karch, Andreas; Limtragool, Kridsanaphong; Phillips, Philip W.

    2016-03-01

    Motivated by the overwhelming evidence some type of quantum criticality underlies the power-law for the optical conductivity and T-linear resistivity in the cuprates, we demonstrate here how a scale-invariant or unparticle sector can lead to a unifying description of the observed scaling forms. We adopt the continuous mass formalism or multi band (flavor) formalism of the unparticle sector by letting various microscopic parameters be mass-dependent. In particular, we show that an effective mass that varies with the flavor index as well as a running band edge and lifetime capture the AC and DC transport phenomenology of the cuprates. A key consequence of the running mass is that the effective dynamical exponent can differ from the underlying bare critical exponent, thereby providing a mechanism for realizing the fractional values of the dynamical exponent required in a previous analysis [1]. We also predict that regardless of the bare dynamical exponent, z, a non-zero anomalous dimension for the current is required. Physically, the anomalous dimension arises because the charge depends on the flavor, mass or energy. The equivalent phenomenon in a d + 1 gravitational construction is the running of the charge along the radial direction. The nature of the superconducting instability in the presence of scale invariant stuff shows that the transition temperature is not necessarily a monotonic function of the pairing interaction.

  10. Holographic entanglement entropy and gravitational anomalies

    CERN Document Server

    Castro, Alejandra; Iqbal, Nabil; Perlmutter, Eric

    2014-01-01

    We study entanglement entropy in two-dimensional conformal field theories with a gravitational anomaly. In theories with gravity duals, this anomaly is holographically represented by a gravitational Chern-Simons term in the bulk action. We show that the anomaly broadens the Ryu-Takayanagi minimal worldline into a ribbon, and that the anomalous contribution to the CFT entanglement entropy is given by the twist in this ribbon. The entanglement functional may also be interpreted as the worldline action for a spinning particle -- that is, an anyon -- in three-dimensional curved spacetime. We demonstrate that the minimization of this action results in the Mathisson-Papapetrou-Dixon equations of motion for a spinning particle in three dimensions. We work out several simple examples and demonstrate agreement with CFT calculations.

  11. The quantum anomalous Hall effect

    OpenAIRE

    LIU, CHAO-XING; Zhang, Shou-Cheng; Qi, Xiao-Liang

    2015-01-01

    The quantum anomalous Hall effect is defined as a quantized Hall effect realized in a system without external magnetic field. Quantum anomalous Hall effect is a novel manifestation of topological structure in many-electron systems, and may have potential applications in future electronic devices. In recent years, quantum anomalous Hall effect has been proposed theoretically and realized experimentally. In this review article, we provide a systematic overview of the theoretical and experimenta...

  12. Anomalous Dimensions of Conformal Baryons

    CERN Document Server

    Pica, Claudio

    2016-01-01

    We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small for a wide range of number of flavours. We also find that this is always smaller than the anomalous dimension of the fermion mass operator. These findings challenge the partial compositeness paradigm.

  13. The Importance of Intergalactic Structure to Gravitationally Lensed Quasars

    CERN Document Server

    Metcalf, R B

    2004-01-01

    Image flux ratio anomalies have been attributed to substructures within the gravitational lens and to small mass halos (M <~ 10^10 Msun) in intergalactic space. In this paper, analytic calculations are presented that help in the understanding of how intergalactic halos affect magnification ratios. It is found that intergalactic halos can produce anomalies at a similar level to those that are observed. Intergalactic halos with masses <10^10 Msun are expected to cause relative deflections between images of order 10 milliarcseconds, which are then magnified by the primary lens. They will also cause fluctuations in the surface density on the several percent level. The importance of intergalactic halos depends strongly on the radial profile of the halos and the primordial power spectrum at small scales. Strongly lensed quasars provide an opportunity to probe these properties. A strong dependence on the QSO redshift is predicted and can be used to distinguish between intergalactic structure and substructure a...

  14. The Origin of Gravitation

    Science.gov (United States)

    Zheng, Sheng Ming

    2012-10-01

    In the natural world, people have discovered four kinds of forces: electromagnetic force, gravitation, weak force, and strong force. Although the gravitation has been discovered more than three hundred years, its mechanism of origin is unclear until today. While investigating the origin of gravitation, I do some experiments discover the moving photons produce gravitation. This discovery shows the origin of gravitation. Meanwhile I do some experiments discover the light interference fringes are produced by the gravitation: my discovery demonstrate light is a particle, but is not a wave-particle duality. Furthermore, applications of this discovery to other moving particles show a similar effect. In a word: the micro particle moving produce gravitation and electromagnetic force. Then I do quantity experiment get a general formula: Reveal the essence of gravitational mass and the essence of electric charge; reveal the origin of gravitation and the essence of matter wave. Along this way, I unify the gravitation and electromagnetic force. Namely I find a natural law that from atomic world to star world play in moving track. See website: https://www.lap-publishing.com/catalog/details/store/gb/book/978-3-8473-2658-8/mechanism-of-interaction-in-moving-matter

  15. Weber's gravitational force as static weak field approximation

    Science.gov (United States)

    Tiandho, Yuant

    2016-02-01

    Weber's gravitational force (WGF) is one of gravitational model that can accommodate a non-static system because it depends not only on the distance but also on the velocity and the acceleration. Unlike Newton's law of gravitation, WGF can predict the anomalous of Mercury and gravitational bending of light near massive object very well. Then, some researchers use WGF as an alternative model of gravitation and propose a new mechanics theory namely the relational mechanics theory. However, currently we have known that the theory of general relativity which proposed by Einstein can explain gravity with very accurate. Through the static weak field approximation for the non-relativistic object, we also have known that the theory of general relativity will reduce to Newton's law of gravity. In this work, we expand the static weak field approximation that compatible with relativistic object and we obtain a force equation which correspond to WGF. Therefore, WGF is more precise than Newton's gravitational law. The static-weak gravitational field that we used is a solution of the Einstein's equation in the vacuum that satisfy the linear field approximation. The expression of WGF with ξ = 1 and satisfy the requirement of energy conservation are obtained after resolving the geodesic equation. By this result, we can conclude that WGF can be derived from the general relativity.

  16. Dark Matter Gravitational Interactions

    CERN Document Server

    Tucker, R W

    1998-01-01

    We argue that the conjectured dark mater in the Universe may be endowed with a new kind of gravitational charge that couples to a short range gravitational interaction mediated by a massive vector field. A model is constructed that assimilates this concept into ideas of current inflationary cosmology. The model is also consistent with the observed behaviour of galactic rotation curves according to Newtonian dynamics. The essential idea is that stars composed of ordinary (as opposed to dark matter) experience Newtonian forces due to the presence of an all pervading background of massive gravitationally charged cold dark matter. The novel gravitational interactions are predicted to have a significant influence on pre-inflationary cosmology. The precise details depend on the nature of a gravitational Proca interaction and the description of matter. A gravitational Proca field configuration that gives rise to attractive forces between dark matter charges of like polarity exhibits homogeneous isotropic eternal cos...

  17. Theory of gravitational interactions

    CERN Document Server

    Gasperini, Maurizio

    2013-01-01

    This reference textbook is an up-to-date and self-contained introduction to the theory of gravitational interactions. The first part of the book follows the traditional presentation of general relativity as a geometric theory of the macroscopic gravitational field. A second, advanced part then discusses the deep analogies (and differences) between a geometric theory of gravity and the gauge theories of the other fundamental interactions. This fills a gap which is present in the context of the traditional approach to general relativity, and which usually makes students puzzled about the role of gravity. The necessary notions of differential geometry are reduced to the minimum, leaving more room for those aspects of gravitational physics of current phenomenological and theoretical interest, such as the properties of gravitational waves, the gravitational interactions of spinors, and the supersymmetric and higher-dimensional generalization of the Einstein equations. Theory of Gravitational Interactions will be o...

  18. Gravitational waves from inflation

    CERN Document Server

    Guzzetti, Maria Chiara; Liguori, Michele; Matarrese, Sabino

    2016-01-01

    The production of a stochastic background of gravitational waves is a fundamental prediction of any cosmological inflationary model. The features of such a signal encode unique information about the physics of the Early Universe and beyond, thus representing an exciting, powerful window on the origin and evolution of the Universe. We review the main mechanisms of gravitational-wave production, ranging from quantum fluctuations of the gravitational field to other mechanisms that can take place during or after inflation. These include e.g. gravitational waves generated as a consequence of extra particle production during inflation, or during the (p)reheating phase. Gravitational waves produced in inflation scenarios based on modified gravity theories and second-order gravitational waves are also considered. For each analyzed case, the expected power-spectrum is given. We discuss the discriminating power among different models, associated with the validity/violation of the standard consistency relation between t...

  19. Gravitation and electromagnetism

    OpenAIRE

    B. G. Sidharth

    2002-01-01

    Maxwell's equations comprise both electromagnetic and gravitational fields. The transverse part of the vector potential belongs to magnetism, the longitudinal one is concerned with gravitation. The Coulomb gauge indicates that longitudinal components of the fields propagate instantaneously. The delta-function singularity of the field of the divergence of the vector potential, referred to as the dilatation center, represents an elementary agent of gravitation. Viewing a particle as a source or...

  20. How does pressure gravitate? Cosmological constant problem confronts observational cosmology

    CERN Document Server

    Narimani, Ali; Scott, Douglas

    2014-01-01

    An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the \\textit{cosmological constant problem}. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the \\textit{Gravitational Aether} proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we in...

  1. Spectrum of anomalous magnetohydrodynamics

    Science.gov (United States)

    Giovannini, Massimo

    2016-05-01

    The equations of anomalous magnetohydrodynamics describe an Abelian plasma where conduction and chiral currents are simultaneously present and constrained by the second law of thermodynamics. At high frequencies the magnetic currents play the leading role, and the spectrum is dominated by two-fluid effects. The system behaves instead as a single fluid in the low-frequency regime where the vortical currents induce potentially large hypermagnetic fields. After deriving the physical solutions of the generalized Appleton-Hartree equation, the corresponding dispersion relations are scrutinized and compared with the results valid for cold plasmas. Hypermagnetic knots and fluid vortices can be concurrently present at very low frequencies and suggest a qualitatively different dynamics of the hydromagnetic nonlinearities.

  2. Detection of anomalous events

    Energy Technology Data Exchange (ETDEWEB)

    Ferragut, Erik M.; Laska, Jason A.; Bridges, Robert A.

    2016-06-07

    A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The system can include a plurality of anomaly detectors that together implement an algorithm to identify low-probability events and detect atypical traffic patterns. The anomaly detector provides for comparability of disparate sources of data (e.g., network flow data and firewall logs.) Additionally, the anomaly detector allows for regulatability, meaning that the algorithm can be user configurable to adjust a number of false alerts. The anomaly detector can be used for a variety of probability density functions, including normal Gaussian distributions, irregular distributions, as well as functions associated with continuous or discrete variables.

  3. Optically Anomalous Crystals

    CERN Document Server

    Shtukenberg, Alexander; Kahr, Bart

    2007-01-01

    Optical anomalies in crystals are puzzles that collectively constituted the greatest unsolved problems in crystallography in the 19th Century. The most common anomaly is a discrepancy between a crystal’s symmetry as determined by its shape or by X-ray analysis, and that determined by monitoring the polarization state of traversing light. These discrepancies were perceived as a great impediment to the development of the sciences of crystals on the basis of Curie’s Symmetry Principle, the grand organizing idea in the physical sciences to emerge in the latter half of the 19th Century. Optically Anomalous Crystals begins with an historical introduction covering the contributions of Brewster, Biot, Mallard, Brauns, Tamman, and many other distinguished crystallographers. From this follows a tutorial in crystal optics. Further chapters discuss the two main mechanisms of optical dissymmetry: 1. the piezo-optic effect, and 2. the kinetic ordering of atoms. The text then tackles complex, inhomogeneous crystals, and...

  4. Pulsars and Gravitational Waves

    CERN Document Server

    Lee, K J; Qiao, G J

    2011-01-01

    The relationship between pulsar-like compact stars and gravitational waves is briefly reviewed. Due to regular spins, pulsars could be useful tools for us to detect ~nano-Hz low-frequency gravitational waves by pulsar-timing array technique; besides, they would also be ~kilo-Hz high-frequency gravitational wave radiators because of their compactness. The wave strain of an isolate pulsar depends on the equation state of cold matter at supra-nuclear densities. Therefore, a real detection of gravitational wave should be very meaningful in gravity physics, micro-theory of elementary strong interaction, and astronomy.

  5. Gravitation in material media

    International Nuclear Information System (INIS)

    When two gravitating bodies reside in a material medium, Newton's law of universal gravitation must be modified to account for the presence of the medium. A modified expression of Newton's law is known in the literature, but lacks a clear connection with existing gravitational theory. Newton's law in the presence of a homogeneous material medium is herein derived on the basis of classical, Newtonian gravitational theory and by a general relativistic use of Archimedes' principle. It is envisioned that the techniques presented herein will be most useful to graduate students and those undergraduate students having prior experience with vector analysis and potential theory.

  6. Discrete interactions and the Pioneer anomalous acceleration Alternative II

    CERN Document Server

    De Souza, M M

    2001-01-01

    The dominant contributions from a discrete gravitational interaction produce the standard potential as an effective continuous field. The sub-dominant contributions are, in a first approximation, linear on $n$, the accumulated number of (discrete) interaction events along the test-body trajectory. For a nearly radial trajectory $n$ is proportional to the transversed distance and its effects may have been observed as the Pioneer anomalous constant radial acceleration, which cannot be observed on the nearly circular planetary orbits. Here we give calculation details of the alternative II, discussed in gr-qc/0106046.

  7. Anomalous precession of planets on a Weyl conformastatic solution

    CERN Document Server

    Capistrano, Abraão J S; Alárcon, Manuel S

    2016-01-01

    In this paper, we investigate the anomalous planets precession in the so-called nearly-newtonian gravitational regime. This limit is obtained from the application of the slow motion condition to the geodesic equations without altering the geodesic deviation equations, which leads to an intermediate gravitational field stronger than the newtonian one. Using a non-standard expression for the perihelion advance from the Weyl conformastatic vacuum solution as a model, we can describe the anomaly in planets precession compared with different observational data from Ephemerides of the Planets and the Moon (EPM2008 and EPM2011) and Planetary and Lunar Ephemeris (INPOP10a). As a result, using the Levenberg-Marquardt algorithm and calculating the related Chi-squared statistic, we find that the anomaly is statistical irrelevant in accordance with INPOP10a observations. As a complement to this work, we also do application to the relativistic precession of giant planets using observational data calibrated with the EPM201...

  8. Those Elusive Gravitational Waves

    Science.gov (United States)

    MOSAIC, 1976

    1976-01-01

    The presence of gravitational waves was predicted by Einstein in his theory of General Relativity. Since then, scientists have been attempting to develop a detector sensitive enough to measure these cosmic signals. Once the presence of gravitational waves is confirmed, scientists can directly study star interiors, galaxy cores, or quasars. (MA)

  9. Spin-1 gravitational waves

    OpenAIRE

    Canfora, F.; Vilasi, G.; Vitale, P.

    2002-01-01

    Gravitational fields invariant for a 2-dimensional Lie algebra of Killing fields [ X,Y] =Y, with Y of light type, are analyzed. The conditions for them to represent gravitational waves are verified and the definition of energy and polarization is addressed; realistic generating sources are described.

  10. Gravitational waves in preheating

    OpenAIRE

    Tilley, Daniel; Maartens, Roy

    2000-01-01

    We study the evolution of gravitational waves through the preheating era that follows inflation. The oscillating inflaton drives parametric resonant growth of scalar field fluctuations, and although super-Hubble tensor modes are not strongly amplified, they do carry an imprint of preheating. This is clearly seen in the Weyl tensor, which provides a covariant description of gravitational waves.

  11. Relativistic gravitation theory

    International Nuclear Information System (INIS)

    On the basis of the special relativity and geometrization principle a relativistic gravitation theory (RGT) is unambiguously constructed with the help of a notion of a gravitational field as a physical field in Faraday-Maxwell spirit, which posesses energy momentum and spins 2 and 0. The source of gravitation field is a total conserved energy-momentum tensor for matter and for gravitation field in Minkowski space. In the RGT conservation laws for the energy momentum and angular momentum of matter and gravitational field hold rigorously. The theory explains the whole set of gravitation experiments. Here, due to the geometrization principle the Riemannian space is of a field origin since this space arises effectively as a result of the gravitation field origin since this space arises effectively as a result of the gravitation field action on the matter. The RGT astonishing prediction is that the Universe is not closed but ''flat''. It means that in the Universe there should exist a ''missing'' mass in some form of matter

  12. Theory of Gravitational Waves

    CERN Document Server

    Tiec, Alexandre Le

    2016-01-01

    The existence of gravitational radiation is a natural prediction of any relativistic description of the gravitational interaction. In this chapter, we focus on gravitational waves, as predicted by Einstein's general theory of relativity. First, we introduce those mathematical concepts that are necessary to properly formulate the physical theory, such as the notions of manifold, vector, tensor, metric, connection and curvature. Second, we motivate, formulate and then discuss Einstein's equation, which relates the geometry of spacetime to its matter content. Gravitational waves are later introduced as solutions of the linearized Einstein equation around flat spacetime. These waves are shown to propagate at the speed of light and to possess two polarization states. Gravitational waves can interact with matter, allowing for their direct detection by means of laser interferometers. Finally, Einstein's quadrupole formulas are derived and used to show that nonspherical compact objects moving at relativistic speeds a...

  13. Gravitation Is Torsion

    CERN Document Server

    Schucking, Engelbert L

    2008-01-01

    The mantra about gravitation as curvature is a misnomer. The curvature tensor for a standard of rest does not describe acceleration in a gravitational field but the \\underline{gradient} of the acceleration (e.g. geodesic deviation). The gravitational field itself (Einstein 1907) is essentially an accelerated reference system. It is characterized by a field of orthonormal four-legs in a Riemann space with Lorentz metric. By viewing vectors at different events having identical leg-components as parallel (teleparallelism) the geometry in a gravitational field defines torsion. This formulation of Einstein's 1907 principle of equivalence uses the same Riemannian metric and the same 1916 field equations for his theory of gravitation and fulfills his vision of General Relativity.

  14. The Gravitational Spacecraft

    CERN Document Server

    D'Aquino, F

    1998-01-01

    There is a electromagnetic factor of correlation between gravitational mass and inertial mass, which in specific electromagnetic conditions, can be reduced, nullified, negated, and increased. This means that gravitational forces can be reduced, nullified, inverted and intensified by means of electromagnetic fields. Such control of the gravitational interaction can have a lot of practical applications. For example, a new concept of spacecraft and aerospace flight arises from the possibility of the electromagnetic control of the gravitational mass.Some theoretical consequences of the mentioned correlation are: the generalization of Newton=92s second law for the motion (New law for Inertia), the deduction of the differential equation for entropy (second law of Thermodynamics), unification of gravitational and electromagnetic interactions .

  15. Gravitational Lensing in Astronomy

    CERN Document Server

    Wambsganss, J

    1998-01-01

    Deflection of light by gravity was predicted by General Relativity and observationaly confirmed in 1919. In the following decades various aspects of the gravitational lens effect were explored theoretically, among them the possibility of multiple or ring-like images of background sources, the use of lensing as a gravitational telescope on very faint and distant objects, and the possibility to determine Hubble's constant with lensing. Only relatively recently gravitational lensing became an observational science after the discovery of the first doubly imaged quasar in 1979. Today lensing is a booming part of astrophysics. In addition to multiply-imaged quasars, a number of other aspects of lensing have been discovered since, e.g. giant luminous arcs, quasar microlensing, Einstein rings, galactic microlensing events, arclets, or weak gravitational lensing. By now literally hundreds of individual gravitational lens phenomena are known. Although still in its childhood, lensing has established itself as a very use...

  16. Anomalous radiative transitions

    International Nuclear Information System (INIS)

    Anomalous transitions involving photons derived by many-body interaction of the form ∂μGμ in the standard model are studied for the first time. This does not affect the equation of motion in the bulk, but modifies the wavefunctions, and causes an unusual transition characterized by a time-independent probability. In the transition probability at a time interval T expressed generally in the form P=TΓ0+P(d), now with P(d)≠0. The diffractive term P(d) has its origin in the overlap of waves of the initial and final states, and reveals the characteristics of waves. In particular, the processes of the neutrino–photon interaction ordinarily forbidden by the Landau–Yang theorem (Γ0=0) manifest themselves through the boundary interaction. The new term leads physical processes over a wide energy range to have finite probabilities. New methods of detecting neutrinos using lasers are proposed, based on this diffractive term; these would enhance the detectability of neutrinos by many orders of magnitude

  17. Gravitational Radiation from Newborn Magnetars

    CERN Document Server

    Stella, L; Israel, G L; Vecchio, A; Stella, Luigi; Oss, Simone Dall'; Israel, GianLuca; Vecchio, Alberto

    2005-01-01

    There is growing evidence that two classes of high-energy sources, the Soft Gamma Repeaters and the Anomalous X-ray Pulsars contain slowly spinning ``magnetars'', i.e. neutron stars whose emission is powered by the release of energy from their extremely strong magnetic fields (>10^15 G. We show here that the enormous energy liberated in the 2004 December 27 giant flare from SGR1806-20 (~5 10^46 erg), together with the likely recurrence time of such events, requires an internal field strength of > 10^16 G. Toroidal magnetic fields of this strength are within an order of magnitude of the maximum fields that can be generated in the core of differentially-rotating neutron stars immediately after their formation, if their initial spin period is of a few milliseconds. A substantial deformation of the neutron star is induced by these magnetic fields and, provided the deformation axis is offset from the spin axis, a newborn fast-spinning magnetar would radiate for a few weeks a strong gravitational wave signal the fr...

  18. Generalized Gravitational Entropy of Interacting Scalar Field and Maxwell Field

    CERN Document Server

    Huang, Wung-Hong

    2014-01-01

    The generalized gravitational entropy proposed by Lewkowycz and Maldacena in recent is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the spacetime. The associated modified area law is consistent with the generalized gravitational entropy. Our investigations have not found the unexpected anomalous surface term.

  19. Gravitational Waves and the Fate of Scalar-Tensor Gravity

    CERN Document Server

    Bettoni, Dario; Hinterbichler, Kurt; Zumalacárregui, Miguel

    2016-01-01

    We investigate the propagation speed of gravitational waves (GWs) in generic scalar-tensor gravity. A difference in the speed of gravity relative to the speed of light can be caused by the emergence of a disformal geometry in the gravitational sector. This requires the background scalar configuration to both spontaneously break Lorentz symmetry and couple to second derivatives of the metric perturbations through the Weyl tensor or higher derivatives of the scalar. The latter requirement allows a division of gravitational theories into two families: those that predict that GWs propagate exactly at the speed of light and those that allow for anomalous speed. Neutron star binary mergers and other GW events with an associated electromagnetic counterpart can place extremely tight constraints on the speed of GWs relative to the speed of light. However, such observations become impossible if the speed is modified too much, as predicted by some models of cosmic acceleration. Complementary measurements of the speed of...

  20. Gravitation and vacuum field

    International Nuclear Information System (INIS)

    This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E → ∞. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory

  1. Gravitation in astrophysics

    International Nuclear Information System (INIS)

    The subject of this volume is the application of relativistic gravity to realistic astronomical phenomena. This volume is divided into two parts. The first is concerned with gravitation in localized systems (including topics such as black hole theory, gravitational radiation theory, and the Newton theory of many-body systems). The second is concerned with gravitation in cosmology (including aspects of inflation, the origin of inhomogeneities and the quantum process of creation of the universe itself. Separate abstracts were prepared for 15 sections of this volume

  2. Alternative Reflections on Gravitation

    OpenAIRE

    Albers, Johann

    1997-01-01

    It is assumed that the primary interaction between two masses m1 and m2 is not attractive as postulated by Newton's law of gravitation, but repulsive. Both m1 and m2 emit and absorb gravitational radiation. Corresponding to the laws of optics the absorption is connected with an impulse transfer that produces the repulsive force. If, however, m1 and m2 are embedded in the gravitational radiation produced by all the masses of the universe the absorption by m1 and m2 leads to a reduction of the ...

  3. Petrology of Anomalous Eucrites

    Science.gov (United States)

    Mittlefehldt, D. W.; Peng, Z. X.; Ross, D. K.

    2015-01-01

    Most mafic achondrites can be broadly categorized as being "eucritic", that is, they are composed of a ferroan low-Ca clinopyroxene, high-Ca plagioclase and a silica phase. They are petrologically distinct from angritic basalts, which are composed of high-Ca, Al-Ti-rich clinopyroxene, Carich olivine, nearly pure anorthite and kirschsteinite, or from what might be called brachinitic basalts, which are composed of ferroan orthopyroxene and high-Ca clinopyroxene, intermediate-Ca plagioclase and ferroan olivine. Because of their similar mineralogy and composition, eucrite-like mafic achondrites formed on compositionally similar asteroids under similar conditions of temperature, pressure and oxygen fugacity. Some of them have distinctive isotopic compositions and petrologic characteristics that demonstrate formation on asteroids different from the parent of the HED clan (e.g., Ibitira, Northwest Africa (NWA) 011). Others show smaller oxygen isotopic distinctions but are otherwise petrologically and compositionally indistinguishable from basaltic eucrites (e.g., Pasamonte, Pecora Escarpment (PCA) 91007). The degree of uniformity in delta O-17 of eucrites and diogenites is one piece of evidence considered to favor of a magma-ocean scenario for their petrogenesis. Given that the O isotopic differences separating Pasamonte and PCA 91007 from other eucrites are small, and that there is an absence of other distinguishing characteristics, a legitimate question is: Did the HED parent asteroid fail to homogenize via a magma-ocean stage, thus explaining outliers like Pasamonte? We are initiating a program of study of anomalous eucrite-like achondrites as one part of our effort to seek a resolution of this issue. Here we present preliminary petrologic information on Asuka (A-) 881394, Elephant Moraine (EET) 87520 and EET 87542. We will have studied several more by conference time.

  4. Gravitational lensing of quasars

    CERN Document Server

    Eigenbrod, Alexander

    2013-01-01

    The universe, in all its richness, diversity and complexity, is populated by a myriad of intriguing celestial objects. Among the most exotic of them are gravitationally lensed quasars. A quasar is an extremely bright nucleus of a galaxy, and when such an object is gravitationally lensed, multiple images of the quasar are produced – this phenomenon of cosmic mirage can provide invaluable insights on burning questions, such as the nature of dark matter and dark energy. After presenting the basics of modern cosmology, the book describes active galactic nuclei, the theory of gravitational lensing, and presents a particular numerical technique to improve the resolution of astronomical data. The book then enters the heart of the subject with the description of important applications of gravitational lensing of quasars, such as the measurement of the famous Hubble constant, the determination of the dark matter distribution in galaxies, and the observation of the mysterious inner parts of quasars with much higher r...

  5. Gravitating BPS Skyrmions

    CERN Document Server

    Gudnason, Sven Bjarke; Sawado, Nobuyuki

    2015-01-01

    The BPS Skyrme model has many exact analytic solutions in flat space. We generalize the model to a curved space or spacetime and find that the solutions can only be BPS for a constant time-time component of the metric tensor. We find exact solutions on the curved spaces: a 3-sphere and a 3-hyperboloid; and we further find an analytic gravitating Skyrmion on the 3-sphere. For the case of a nontrivial time-time component of the metric, we suggest a potential for which we find analytic solutions on anti-de Sitter and de Sitter spacetimes in the limit of no gravitational backreaction. We take the gravitational coupling into account in numerical solutions and show that they are well approximated by the analytic solutions for weak gravitational coupling.

  6. Observation of Gravitational Waves

    Science.gov (United States)

    Gonzalez, Gabriela

    2016-06-01

    On September 14 2015, the two LIGO gravitational wave detectors in Hanford, Washington and Livingston, Louisiana registered a nearly simultaneous signal with time-frequency properties consistent with gravitational-wave emission by the merger of two massive compact objects. Further analysis of the signals by the LIGO Scientific Collaboration and Virgo Collaboration revealed that the gravitational waves detected by LIGO came from the merger of a binary black hole (BBH) system approximately 420 Mpc distant (z=0.09) with constituent masses of 36 and 29 M_sun. I will describe the details of the observation, the status of ground-based interferometric detectors, and prospects for future observations in the new era of gravitational wave astronomy.

  7. Smooth sandwich gravitational waves

    OpenAIRE

    Podolsky, J.

    1998-01-01

    Gravitational waves which are smooth and contain two asymptotically flat regions are constructed from the homogeneous pp-waves vacuum solution. Motion of free test particles is calculated explicitly and the limit to an impulsive wave is also considered.

  8. Weak gravitational lensing

    CERN Document Server

    Hoekstra, H

    2014-01-01

    Luminous tracers have been used extensively to map the large-scale matter distribution in the Universe. Similarly the dynamics of stars or galaxies can be used to estimate masses of galaxies and clusters of galaxies. However, assumptions need to be made about the dynamical state or how well galaxies trace the underlying dark matter distribution. The gravitational tidal ?field a?ffects the paths of photons, leading to observable e?ffects. This phenomenon, gravitational lensing, has become an important tool in cosmology because it probes the mass distribution directly. In these lecture notes we introduce the main relevant quantities and terminology, but the subsequent discussion is mostly limited to weak gravitational lensing, the small coherent distortion of the shapes of distant galaxies by intervening structures. We focus on some of the issues in measuring accurate shapes and review the various applications of weak gravitational lensing, as well as some recent results.

  9. On the gravitational redshift

    CERN Document Server

    Wilhelm, Klaus

    2013-01-01

    The study of the gravitational redshift -- a relative wavelength increase of $\\approx 2 \\times 10^{-6}$ was predicted for solar radiation by Einstein in 1908 -- is still an important subject in modern physics. In a dispute whether or not atom interferometry experiments can be employed for gravitational redshift measurements, two research teams have recently disagreed on the physical cause of the shift. Regardless of any discussion on the interferometer aspect -- we find that both groups of authors miss the important point that the ratio of gravitational to the electrostatic forces is generally very small. For instance, the gravitational force acting on an electron in a hydrogen atom situated in the Sun's photosphere to the electrostatic force between the proton and the electron is approximately $3 \\times 10^{-21}$. A comparison of this ratio with the predicted and observed solar redshift indicates a discrepancy of many orders of magnitude. Here we show, with Einstein's early assumption of the frequency of spe...

  10. Superluminal Gravitational Waves

    CERN Document Server

    Moffat, J W

    2014-01-01

    The quantum gravity effects of vacuum polarization of gravitons propagating in a curved spacetime cause the quantum vacuum to act as a dispersive medium with a refractive index. Due to this dispersive medium gravitons acquire superluminal velocities. The dispersive medium is produced by higher derivative curvature contributions to the effective gravitational action. It is shown that in a Friedmann-Lema\\^{i}tre-Robertson-Walker spacetime in the early universe near the Planck time $t_{\\rm PL}\\gtrsim 10^{-43}\\,{\\rm sec}$, the speed of gravitational waves $c_g\\gg c_{g0}=c_0$, where $c_{g0}$ and $c_0$ are the speeds of gravitational waves and light today. The large speed of gravitational waves stretches their wavelengths to super-horizon sizes, allowing them to be observed in B-polarization experiments.

  11. Gravitational Holographic Teleportation

    OpenAIRE

    De Aquino, Fran

    2013-01-01

    A process of teleportation is here studied. It involves holography and reduction of the gravitational mass of the bodies to be transported. We show that if a holographic three-dimensional image of a body is created and sent to another site and the gravitational mass of the body is reduced to a specific range, then the body will disappear and posteriorly will reappear exactly where its holographic three-dimensional image was sent.

  12. Gravitation and Electricity

    Directory of Open Access Journals (Sweden)

    Stavroulakis N.

    2008-04-01

    Full Text Available The equations of gravitation together with the equations of electromagnetism in terms of the General Theory of Relativity allow to conceive an interdependence between the gravitational field and the electromagnetic field. However the technical difficulties of the relevant problems have precluded from expressing clearly this interdependence. Even the simple problem related to the field generated by a charged spherical mass is not correctly solved. In the present paper we reexamine from the outset this problem and propose a new solution.

  13. Listening music of gravitation

    International Nuclear Information System (INIS)

    Achievements of precision experiments in Japan (TAMA project) and USA (LIGO Laboratory) in the field of registration of gravitation waves using interferometric gravitational wave detectors are described. Works of the GEO groups in Hannover (Germany) and Vigro (Italy) are noted. Interferometer operation in synchronization during 160 hours demonstrating viability of the technique and its reliability is recorded. Advances in the field of the data analysis with the aim of recording of cosmic signal from noise of the interferometer are noted

  14. Anomalous position of the gallbladder

    Energy Technology Data Exchange (ETDEWEB)

    Han, Tae II; Lim, Joo Won; Ko, Young Tae; Lee, Dong Ho; Yoon, Yup [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1994-12-15

    To determine the significance of anomalous position of the gallbladder. Sixteen patients with anomalous position of the gallbladder were evaluated for analysis. The diagnosis was confirmed by ultrasonography(15 patients) and oral cholecystography(1 patient). Among those, six patients underwent CT scan and a patient had 99mTc-DISIDA scan. The images were analysed with respect to the location of the GB and configuration and associated abnormality of the liver and hepatobiliary systems. Medical records of each patient were also reviewed. Among 16 patients having an anomalous position of the gallbladder, nine had retrodisplaced gallbladder, four had left-sided gallbladder, two had supra hepatic gallbladder, and one had floating gallbladder. Except for one patient, fifteen had abnormality in the liver such as focal atrophic or hypoplastic change and liver cirrhosis. Intrahepatic stones were demonstrated in 6 patients. Our results showed that anomalous position of the gallbladder was commonly associated with atrophy or hypoplasia of the liver rather than congenital in origin. The possibility of an anomalous location of gallbladder should be kept in mind when GB is not in its normal location.

  15. Anomalous x-ray scattering

    International Nuclear Information System (INIS)

    The availability of tunable synchrotron radiation has made it possible systematically to perform x-ray diffraction studies in regions of anomalous scattering near absorption edges, e.g. in order to derive phase information for crystal structure determination. An overview is given of recent experimental and theoretical work and discuss the properties of the anomalous atomic scattering factor, with emphasis on threshold resonances and damping effects. The results are applied to a discussion of the very strong anomalous dispersion recently observed near the L3 edge in a cesium complex. Also given is an overview of elements and levels where similar behavior can be expected. Finally, the influence of solid state and chemical effects on the absorption edge structure is discussed. 64 references

  16. Effective actions for anomalous hydrodynamics

    International Nuclear Information System (INIS)

    We argue that an effective field theory of local fluid elements captures the constraints on hydrodynamic transport stemming from the presence of quantum anomalies in the underlying microscopic theory. Focussing on global current anomalies for an arbitrary flavour group, we derive the anomalous constitutive relations in arbitrary even dimensions. We demonstrate that our results agree with the constraints on anomaly governed transport derived hitherto using a local version of the second law of thermodynamics. The construction crucially uses the anomaly inflow mechanism and involves a novel thermofield double construction. In particular, we show that the anomalous Ward identities necessitate non-trivial interaction between the two parts of the Schwinger-Keldysh contour

  17. Convective cell formation and anomalous diffusion due to electromagnetic drift wave turbulence

    International Nuclear Information System (INIS)

    Convective cell formation and spectral cascade processes due to gravitational drift Alfven waves are studied using a new type of model equation. Conservation relations are derived and explosive instability is found for systems near marginal finite β stability. This instability also remains when the effects of poor as well as favorable curvature regions are included, i.e., for ballooning modes. The anomalous diffusion due to convective cells and quasi-linear effects are compared

  18. Astrometric detection of gravitational effects of quantum vacuum

    Science.gov (United States)

    Vecchiato, Alberto; Gai, Mario; Hajdukovic, Dragan

    2015-08-01

    In a series of recent papers it was suggested that the pairs of virtual particles-antiparticles composing the Quantum Vacuum (QV) can behave like gravitational dipoles with both attractive and repulsive interaction. If verified, this hypothesis would give raise to a series of gravitational effects at different scale length not yet considered in current gravity theories, and it may support galactic and cosmological models alternative to those involving Dark Matter and Dark Energy.Within the boundaries of the Solar System, the most promising targets for testing the gravitational QV conjecture are the binary trans-neptunian objects (TNOs). The gravitational action of the QV, in fact, would manifest itself as an external force inducing an anomalous precession, i.e. an excess shift of the longitude of the pericenter in the orbit of the TNO satellite which, e.g., for the UX25 candidate and under reasonable working hypothesis, was estimated to be about 0.23 arcsec per orbit.In this work we analyze in some detail the feasibility of testing the gravitational QV hypothesis estimating the above effect with ground-based and spaceborne astrometric observations. Several observing scenarios are explored here, including those using conventional and adaptive optics telescopes from ground, some spaceborne telescopes, and by exploring a list of possible candidates.

  19. Measurement of gravitational radiation

    International Nuclear Information System (INIS)

    The present article first describes some possible principles and mechanisms for detecting the gravitational radiation, and then outlines measuring techniques required for its detection. Some major issues concerned, present status of research and future prospects are also discussed. There are two possible detectors. One is the resonance type detector, which uses an elastic body with a considerable mass as antenna to catch the gravitational radiation. Gravitational radiation entering the elastic body causes an internal stress, resulting in vibration. Thus, a resonance type detector consists of an elastic body acting as antenna to catch gravitational radiation, and a transducer that converts the mechanical vibration of the antenna into electrical signals. The antenna and transducer should be contained in a vacuum highly protected from external acoustic and electromagnetic noise as well as external vibrations. Another possible detector uses a laser interferometer to detect a change in the distance between two bodies caused by gravitational radiation. Some techniques that could provide a tool for measuring such extremely small vibrations are also described and discussed. (N.K.)

  20. Anomalous bootstrap current due to drift waves

    International Nuclear Information System (INIS)

    An anomalous parallel current driven by radial flux in tokamak is discussed. Drift waves, which cause an anomalous cross field diffusion, can generate a parallel current in a sheared magnetic field, if the fluctuation level has radial dependence. (author)

  1. Gravitation and spacetime

    CERN Document Server

    Ohanian, Hans C

    2013-01-01

    The third edition of this classic textbook is a quantitative introduction for advanced undergraduates and graduate students. It gently guides students from Newton's gravitational theory to special relativity, and then to the relativistic theory of gravitation. General relativity is approached from several perspectives: as a theory constructed by analogy with Maxwell's electrodynamics, as a relativistic generalization of Newton's theory, and as a theory of curved spacetime. The authors provide a concise overview of the important concepts and formulas, coupled with the experimental results underpinning the latest research in the field. Numerous exercises in Newtonian gravitational theory and Maxwell's equations help students master essential concepts for advanced work in general relativity, while detailed spacetime diagrams encourage them to think in terms of four-dimensional geometry. Featuring comprehensive reviews of recent experimental and observational data, the text concludes with chapters on cosmology an...

  2. Maxwell, Gravitation, and Hodge

    CERN Document Server

    Sattinger, D H

    2013-01-01

    Since Einstein's fundamental paper of 1915, gravitation has been synonymous with General Relativitiy, while theories based on Lorentz invariance have been dismissed as formal analogies. Consequently modern cosmology focusses exclusively on Einstein's geometric theory, which is unnecessarily cumbersome in regions of weak fields, while Maxwell's equations are far more tractable. It is shown here that Maxwell's equations are an {\\it artifact} of Hodge theory, geometric in nature, independent of any specific physical mechanisms, and valid for any force field, attractive or repulsive, generated by a material density and current. In particular, Maxwell's equations apply to weak gravitational fields -- those in Minkowski space-time. Classical analysis and linear partial differential equations therefore have a role to play in modern problems in cosmology. The gravitational field generated by the rotation of a spherical body is computed explicitly using a multipole expansion; and the method is compared with the Lense-...

  3. Anomalous-viscosity current drive

    Science.gov (United States)

    Stix, T.H.; Ono, M.

    1986-04-25

    The present invention relates to a method and apparatus for maintaining a steady-state current for magnetically confining the plasma in a toroidal magnetic confinement device using anomalous viscosity current drive. A second aspect of this invention relates to an apparatus and method for the start-up of a magnetically confined toroidal plasma.

  4. QCD Anomalous Structure of Electron

    OpenAIRE

    Slominski, Wojciech

    1998-01-01

    The parton content of the electron is analyzed within perturbative QCD. It is shown that electron acquires an anomalous component from QCD, analogously to photon. The evolution equations for the `exclusive' and `inclusive' electron structure function are constructed and solved numerically in the asymptotic $Q^2$ region.

  5. Anomalous magnetic moment of anyons

    CERN Document Server

    Gat, G; Gat, Gil; Ray, Rashmi

    1994-01-01

    The anomalous magnetic moment of anyons is calculated to leading order in a 1/N expansion. It is shown that the gyromagnetic ratio g remains 2 to the leading order in 1/N. This result strongly supports that obtained in \\cite{poly}, namely that g=2 is in fact exact.

  6. Nature of Gravitation

    CERN Document Server

    Rykov, A V

    2001-01-01

    The photoeffect, (vacuum analogue of the photoelectric effect,) is used to study the structure of the physical vacuum, the outcome of which is the basis for an hypothesis on the nature of gravitation and inertia. The source of gravitation is the vacuum which has a weak massless elementary electrical dipole (+/-) charge. Inertia is the result of the elastic force of the vacuum in opposition to the accelerated motion of material objects. The vacuum is seen as the source of attraction for all bodies according to the law of induction.

  7. Gravitation: Foundations and Frontiers

    Science.gov (United States)

    Padmanabhan, T.

    2010-01-01

    1. Special relativity; 2. Scalar and electromagnetic fields in special relativity; 3. Gravity and spacetime geometry: the inescapable connection; 4. Metric tensor, geodesics and covariant derivative; 5. Curvature of spacetime; 6. Einstein's field equations and gravitational dynamics; 7. Spherically symmetric geometry; 8. Black holes; 9. Gravitational waves; 10. Relativistic cosmology; 11. Differential forms and exterior calculus; 12. Hamiltonian structure of general relativity; 13. Evolution of cosmological perturbations; 14. Quantum field theory in curved spacetime; 15. Gravity in higher and lower dimensions; 16. Gravity as an emergent phenomenon; Notes; Index.

  8. Gravitational-Wave Astronomy

    Science.gov (United States)

    Kelly, Bernard J.

    2010-01-01

    Einstein's General Theory of Relativity is our best classical description of gravity, and informs modern astronomy and astrophysics at all scales: stellar, galactic, and cosmological. Among its surprising predictions is the existence of gravitational waves -- ripples in space-time that carry energy and momentum away from strongly interacting gravitating sources. In my talk, I will give an overview of the properties of this radiation, recent breakthroughs in computational physics allowing us to calculate the waveforms from galactic mergers, and the prospect of direct observation with interferometric detectors such as LIGO and LISA.

  9. Scalar Gravitational Waves

    Science.gov (United States)

    Mottola, Emil

    2016-03-01

    General Relativity receives quantum corrections relevant at macroscopic distance scales and near event horizons. These arise from the conformal scalar degree of freedom in the extended effective field theory (EFT) of gravity generated by the trace anomaly of massless quantum fields in curved space. Linearized around flat space this quantum scalar degree of freedom combines with the conformal part of the metric and predicts the existence of scalar spin-0 ``breather'' propagating gravitational waves in addition to the transverse tensor spin-2 waves of classical General Relativity. Estimates of the expected strength of scalar gravitational radiation from compact astrophysical sources are given.

  10. Gravitational Waves: The Evidence Mounts

    Science.gov (United States)

    Wick, Gerald L.

    1970-01-01

    Reviews the work of Weber and his colleagues in their attempts at detecting extraterrestial gravitational waves. Coincidence events recorded by special detectors provide the evidence for the existence of gravitational waves. Bibliography. (LC)

  11. Multiple imaging by gravitational waves

    OpenAIRE

    Faraoni, Valerio

    1997-01-01

    Gravitational waves act like lenses for the light propagating through them. This phenomenon is described using the vector formalism employed for ordinary gravitational lenses, which was proved to be applicable also to a non-stationary spacetime, with the appropriate modifications. In order to have multiple imaging, an approximate condition analogous to that for ordinary gravitational lenses must be satisfied. Certain astrophysical sources of gravitational waves satisfy this condition, while t...

  12. Anomalous heat conduction and anomalous diffusion in nonlinear lattices, single walled nanotubes, and billiard gas channels

    OpenAIRE

    Li, Baowen; Wang, Jiao; Wang, Lei; Zhang, Gang

    2004-01-01

    We study anomalous heat conduction and anomalous diffusion in low dimensional systems ranging from nonlinear lattices, single walled carbon nanotubes, to billiard gas channels. We find that in all discussed systems, the anomalous heat conductivity can be connected with the anomalous diffusion, namely, if energy diffusion is $\\sigma^2(t)\\equiv =2Dt^{\\alpha} (01$) implies an anomalous heat conduction with a divergent thermal conductivity ($\\beta>0$), and more interestingly, a subdiffusion ($\\a...

  13. The Gravitational Invisibility

    OpenAIRE

    De Aquino, Fran

    2015-01-01

    The possible obtention of invisibility by means of a gravitational method is shown in this work. This method is based on a gravity control process patented on 2008 (BR Patent Number: PI0805046-5). It goes far beyond the known methods of invisibility and camouflage, which use the principles of light refraction to allow light to pass right through an object (metamaterials).

  14. Probing Gravitational Dark Matter

    CERN Document Server

    Ren, Jing

    2015-01-01

    So far all evidences of dark matter (DM) come from astrophysical and cosmological observations, due to the gravitational interactions of DM. It is possible that the true DM particle in the universe joins gravitational interactions only, but nothing else. Such a Gravitational DM (GDM) acts as a weakly interacting massive particle (WIMP), which is conceptually simple and attractive. In this work, we explore this direction by constructing the simplest scalar GDM particle $\\chi_s$. It is a $\\mathbb{Z}_2$ odd singlet under the standard model (SM) gauge group, and naturally joins the unique dimension-4 interaction with Ricci curvature, $\\xi_s\\chi_s^2{\\cal R}$, where $\\xi_s$ is the dimensionless nonminimal coupling. We demonstrate that this gravitational interaction $\\xi_s\\chi_s^2{\\cal R}$, together with Higgs-curvature nonminimal coupling term $\\xi_h H^\\dag H {\\cal R}$, induces effective couplings between $\\chi_s^2$ and SM fields which can account for the observed DM thermal relic abundance. We analyze the annihila...

  15. Alternative equations of gravitation

    International Nuclear Information System (INIS)

    It is shown, trough a new formalism, that the quantum fluctuation effects of the gravitational field in Einstein's equations are analogs to the effects of a continuum medium in Maxwell's Electrodynamics. Following, a real example of the applications of these equations is studied. Qunatum fluctuations effects as perturbation sources in Minkowski and Friedmann Universes are examined. (L.C.)

  16. The Radio Wavelength Time Delay of Gravitational Lens 0957+561

    CERN Document Server

    Haarsma, D B; Lehár, J; Burke, Bernard F; Haarsma, Deborah B.; Hewitt, Jacqueline N.; Lehár, Joseph; Burke, Bernard F.

    1999-01-01

    The gravitational lens 0957+561 was monitored with the Very Large Array from 1979 to 1997. The 6 cm light curve data from 1995-1997 and the 4 cm data from 1990-1997 are reported here. At 4 cm, the intrinsic source variations occur earlier and are twice as large as the corresponding variations at 6 cm. The VLBI core and jet components have different magnification factors, leading to different flux ratios for the varying and non-varying portions of the VLA light curves. Using both the PRHQ and Dispersion statistical techniques, we determined the time delay, core flux ratio, and excess non-varying B image flux density. The fits were performed for the 4 cm and 6 cm light curves, both individually and jointly, and we used Gaussian Monte Carlo data to estimate 68% statistical confidence levels. The delay estimates from each individual wavelength were inconsistent given the formal uncertainties, suggesting that there are unmodeled systematic errors in the analysis. We roughly estimate the systematic uncertainty in t...

  17. Source-position transformation: an approximate invariance in strong gravitational lensing

    Science.gov (United States)

    Schneider, Peter; Sluse, Dominique

    2014-04-01

    The main obstacle that gravitational lensing has in determining accurate masses of deflectors, or in determining precise estimates for the Hubble constant, is the degeneracy of lensing observables with respect to the mass-sheet transformation (MST). The MST is a global modification of the mass distribution which leaves all image positions, shapes, and flux ratios invariant, but which changes the time delay. Here we show that another global transformation of lensing mass distributions exists which leaves image positions and flux ratios almost invariant, and of which the MST is a special case. As is the case for the MST, this new transformation only applies if one considers only those source components that are at the same distance from us. Whereas for axi-symmetric lenses this source position transformation exactly reproduces all strong lensing observables, it does so only approximately for more general lens situations. We provide crude estimates for the accuracy with which the transformed mass distribution can reproduce the same image positions as the original lens model, and present an illustrative example of its performance. This new invariance transformation is most likely the reason why the same strong lensing information can be accounted for with rather different mass models.

  18. GRAVITATIONAL WAVES AND QUANTUM THEORY

    OpenAIRE

    Trunev A. P.

    2014-01-01

    In this article we consider gravitation theory in multidimensional space. The model of the metric satisfying the basic requirements of quantum theory is proposed. It is shown that gravitational waves are described by the Liouville equation. Schrödinger conjecture about the Schrödinger wave function and gravitational waves has been proved

  19. Weak Gravitational Lensing

    Science.gov (United States)

    Pires, Sandrine; Starck, Jean-Luc; Leonard, Adrienne; Réfrégier, Alexandre

    2012-03-01

    This chapter reviews the data mining methods recently developed to solve standard data problems in weak gravitational lensing. We detail the different steps of the weak lensing data analysis along with the different techniques dedicated to these applications. An overview of the different techniques currently used will be given along with future prospects. Until about 30 years ago, astronomers thought that the Universe was composed almost entirely of ordinary matter: protons, neutrons, electrons, and atoms. The field of weak lensing has been motivated by the observations made in the last decades showing that visible matter represents only about 4-5% of the Universe (see Figure 14.1). Currently, the majority of the Universe is thought to be dark, that is, does not emit electromagnetic radiation. The Universe is thought to be mostly composed of an invisible, pressure less matter - potentially relic from higher energy theories - called "dark matter" (20-21%) and by an even more mysterious term, described in Einstein equations as a vacuum energy density, called "dark energy" (70%). This "dark" Universe is not well described or even understood; its presence is inferred indirectly from its gravitational effects, both on the motions of astronomical objects and on light propagation. So this point could be the next breakthrough in cosmology. Today's cosmology is based on a cosmological model that contains various parameters that need to be determined precisely, such as the matter density parameter Omega_m or the dark energy density parameter Omega_lambda. Weak gravitational lensing is believed to be the most promising tool to understand the nature of dark matter and to constrain the cosmological parameters used to describe the Universe because it provides a method to directly map the distribution of dark matter (see [1,6,60,63,70]). From this dark matter distribution, the nature of dark matter can be better understood and better constraints can be placed on dark energy

  20. Anomalous hydrodynamics in two dimensions

    Indian Academy of Sciences (India)

    Rabin Banerjee

    2016-02-01

    A new approach is presented to discuss two-dimensional hydrodynamics with gauge and gravitational anomalies. Exact constitutive relations for the stress tensor and charge current are obtained. Also, a connection between response parameters and anomaly coefficients is discussed. These are new results which, in the absence of the gauge sector, reproduce the results found by the gradient expansion approach.

  1. How does pressure gravitate? Cosmological constant problem confronts observational cosmology

    Science.gov (United States)

    Narimani, Ali; Afshordi, Niayesh; Scott, Douglas

    2014-08-01

    An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the cosmological constant problem. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the Gravitational Aether proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we include Planck together with WMAP and BICEP2 polarization cosmic microwave background (CMB) observations. Taken at face value, this data combination excludes both GR and GA at around the 3 σ level. However, including higher resolution CMB observations (``highL'') or baryonic acoustic oscillations (BAO) pushes the best fit closer to GR, excluding the Gravitational Aether solution to the cosmological constant problem at the 4- 5 σ level. This constraint effectively places a limit on the anomalous coupling to pressure in the parametrized post-Newtonian (PPN) expansion, ζ4 = 0.105 ± 0.049 (+highL CMB), or ζ4 = 0.066 ± 0.039 (+BAO). These represent the most precise measurement of this parameter to date, indicating a mild tension with GR (for ΛCDM including tensors, with 0ζ4=), and also among different data sets.

  2. How does pressure gravitate? Cosmological constant problem confronts observational cosmology

    International Nuclear Information System (INIS)

    An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the cosmological constant problem. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the Gravitational Aether proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we include Planck together with WMAP and BICEP2 polarization cosmic microwave background (CMB) observations. Taken at face value, this data combination excludes both GR and GA at around the 3 σ level. However, including higher resolution CMB observations (''highL'') or baryonic acoustic oscillations (BAO) pushes the best fit closer to GR, excluding the Gravitational Aether solution to the cosmological constant problem at the 4- 5 σ level. This constraint effectively places a limit on the anomalous coupling to pressure in the parametrized post-Newtonian (PPN) expansion, ζ4 = 0.105 ± 0.049 (+highL CMB), or ζ4 = 0.066 ± 0.039 (+BAO). These represent the most precise measurement of this parameter to date, indicating a mild tension with GR (for ΛCDM including tensors, with 0ζ4=), and also among different data sets

  3. Minimal muon anomalous magnetic moment

    CERN Document Server

    Biggio, Carla

    2014-01-01

    We classify all possible one-particle (scalar and fermion) extensions of the Standard Model that can contribute to the anomalous magnetic moment of leptons. We review the cases already discussed in the literature and complete the picture by performing the calculation for a fermionic doublet with hypercharge -3/2. We conclude that, out of the listed possibilities, only two scalar leptoquarks and the pseudoscalar of a peculiar two-Higgs-doublet model could be the responsibles for the muon anomalous magnetic moment discrepancy. Were this the case, this particles could be seen in the next LHC run. To this aim, especially to test the leptoquark hypothesis, we suggest to look for final states with tops and muons.

  4. Anomalous Diffusion in Velocity Space

    OpenAIRE

    Trigger, S. A.

    2009-01-01

    The problem of anomalous diffusion in the momentum space is considered on the basis of the appropriate probability transition function (PTF). New general equation for description of the diffusion of heavy particles in the gas of the light particles is formulated on basis of the new approach similar to one in coordinate space (S. Trigger et al.). The obtained results permit to describe the various situations when the probability transition function (PTF) has a long tail in the momentum space. ...

  5. Experimental search for anomalous spin-spin interactions

    International Nuclear Information System (INIS)

    This paper reports on a Cavendish-type torsion pendulum, having test masses with 2.5 x 1011 polarized electrons and attracting masses with 8 x 1023 polarized electrons, is used to search for an anomalous spin interaction of macroscopic range. Competition from magnetic forces is reduced by using ferrimagnetic Dy-Fe masses which exhibit orbital compensation of the electron spin magnetic moments. Combined with magnetic shielding, the sensitivity is 2 x 10-4 of the gravitational force. Fluctuations set the overall experimental limit at about 5 times this level. The authors' results set limits on electron spin interactions and on moments which are not of electromagnetic origin. In terms of a standard dipole-dipole form, the limit is 1.5 x 20-12 of the interaction strength between the magnetic moments of the electrons. Compared to previous results, this is a six-fold improvement

  6. (Non)renormalization of Anomalous Conductivities and Holography

    CERN Document Server

    Gursoy, Umut

    2014-01-01

    The chiral magnetic and the chiral vortical effects are recently discovered phenomena arising from chiral gauge and gravitational anomalies that lead to generation of electric currents in presence of magnetic field or vorticity. The magnitude of these effects is determined by the anomalous conductivities. These conductivities can be calculated by the linear response theory, and in the strong coupling limit this calculation can be carried out by the holographic techniques. Earlier calculations in case of conformal field theories indicate non-renormalization of these conductivities where the holographic calculation agrees with the free field limit. We extend this holographic study to non-conformal theories exhibiting mass-gap and confinement-deconfinement type transitions in a holographic model based on the analytic black hole solution of Gao and Zhang. We show that radiative corrections are also absent in these non-conformal theories confirming indirect arguments of Jensen et al in a direct and non-trivial fas...

  7. Possible measurable effects of light propagating in electromagnetized vacuum, as predicted by a scalar tensor theory of gravitation

    CERN Document Server

    Raptis, T E

    2013-01-01

    The effect of static electromagnetic fields on the propagation of light is analyzed in the context of a particular class of scalar-tensor gravitational theories. It is found that for appropriate field configurations and light polarization, anomalous amplitude variations of the light as it propagates in either a magnetized or electrified vacuum are strong enough to be detectable in relatively simple laboratory experiments.

  8. The gravitational wave experiment

    Science.gov (United States)

    Bertotti, B.; Ambrosini, R.; Asmar, S. W.; Brenkle, J. P.; Comoretto, G.; Giampieri, G.; Less, L.; Messeri, A.; Wahlquist, H. D.

    1992-01-01

    Since the optimum size of a gravitational wave detector is the wave length, interplanetary dimensions are needed for the mHz band of interest. Doppler tracking of Ulysses will provide the most sensitive attempt to date at the detection of gravitational waves in the low frequency band. The driving noise source is the fluctuations in the refractive index of interplanetary plasma. This dictates the timing of the experiment to be near solar opposition and sets the target accuracy for the fractional frequency change at 3.0 x 10 exp -14 for integration times of the order of 1000 sec. The instrumentation utilized by the experiment is distributed between the radio systems on the spacecraft and the seven participating ground stations of the Deep Space Network and Medicina. Preliminary analysis is available of the measurements taken during the Ulysses first opposition test.

  9. Gravitationally induced quantum transitions

    Science.gov (United States)

    Landry, A.; Paranjape, M. B.

    2016-06-01

    In this paper, we calculate the probability for resonantly inducing transitions in quantum states due to time-dependent gravitational perturbations. Contrary to common wisdom, the probability of inducing transitions is not infinitesimally small. We consider a system of ultracold neutrons, which are organized according to the energy levels of the Schrödinger equation in the presence of the Earth's gravitational field. Transitions between energy levels are induced by an oscillating driving force of frequency ω . The driving force is created by oscillating a macroscopic mass in the neighborhood of the system of neutrons. The neutron lifetime is approximately 880 sec while the probability of transitions increases as t2. Hence, the optimal strategy is to drive the system for two lifetimes. The transition amplitude then is of the order of 1.06 ×10-5, and hence with a million ultracold neutrons, one should be able to observe transitions.

  10. Gravitationally induced CP effects

    International Nuclear Information System (INIS)

    We study the gravitational analogues of CP violating effects in quantum chromodynamics. These arise through the addition to the action of terms THETA ∫Rsup(ab*)sub(μν)Rsup(μν)sub(ab) and THETA' ∫fsub(μν) *fsup(μν) where Rsup(ab)sub(μν) and fsub(μν) are respectively the curvature tensor and Maxwell field tensor. Both terms can be non-trivial in spacetimes with sufficiently complicated topology. The QCD plus QED plus QGD (quantum gravidynamics) contributions may be combined in a manner which leaves the QCD quark sector as before but the presence of massless neutrinos (or spin 3/2 gravitinos) removes the pure QGD CP violation. The dominant new effect thus arises in the charged leptonic sector from THETA' ∫fsub(μν)*fsup(μν) and is formally independent of the gravitational constant. (orig.)

  11. Gravitation and electromagnetism

    CERN Document Server

    Apsel, D

    1979-01-01

    Through an examination of the Bohm-Aharonov experiment, a new theory of gravitation and electromagnetism is proposed. The fundamental assumption of the theory is that the motion of a particle in a combination of gravitational and electromagnetic fields is determined from a variational principle of the form delta integral /sub A//sup B /d tau =0. The form of the physical time is determined from an examination of the Maxwell-Einstein action function. The field and motion equations are formally identical to those of Maxwell-Einstein theory. The theory predicts that even in a field-free region of space, electromagnetic potentials can alter the phase of a wave function and the lifetime of a charged particle. The phase alteration has been observed in the Bohm-Aharonov experiment. There is an indication that the lifetime alteration has shown up in a recent CERN storage ring experiment. Experimental tests are proposed. (11 refs).

  12. Cosmology with Gravitational Lensing

    CERN Document Server

    Heavens, Alan

    2011-01-01

    In these lectures I give an overview of gravitational lensing, concentrating on theoretical aspects, including derivations of some of the important results. Topics covered include the determination of surface mass densities of intervening lenses, as well as the statistical analysis of distortions of galaxy images by general inhomogeneities (cosmic shear), both in 2D projection on the sky, and in 3D where source distance information is available. 3D mass reconstruction and the shear ratio test are also considered, and the sensitivity of observables to Dark Energy is used to show how its equation of state may be determined using weak lensing. Finally, the article considers the prospect of testing Einstein's General Relativity with weak lensing, exploiting the differences in growth rates of perturbations in different models.} \\abstract{In these lectures I give an overview of gravitational lensing, concentrating on theoretical aspects, including derivations of some of the important results. Topics covered include...

  13. Cosmology with gravitational lenses

    Science.gov (United States)

    Falco, E. E.

    2009-05-01

    Gravitational lenses yield a very high rate of return on observational investment. Given their scarcity, their impact on our knowledge of the universe is very significant. In the weak-field limit, lensing studies are based on well-established physics and thus offer a straightforward approach to pursue many currently pressing problems of astrophysics. Examples of these are the significance of dark matter and the density, age and size of the universe. I present recent developments in cosmological applications of gravitational lenses, regarding estimates of the Hubble constant using strong lensing of quasars. I describe our recent measurements of time delays for the images of SDSS1004+4112, and discuss prospects for the future utilizing synoptic telescopes, planned and under construction.

  14. Spacetime, Geometry and Gravitation

    CERN Document Server

    Sharan, Pankaj

    2009-01-01

    This introductory textbook on the general theory of relativity presents a solid foundation for those who want to learn about relativity. The subject is presented in a physically intuitive, but mathematically rigorous style. The topic of relativity is covered in a broad and deep manner. Besides, the aim is that after reading the book a student should not feel discouraged when she opens advanced texts on general relativity for further reading. The book consists of three parts: An introduction to the general theory of relativity. Geometrical mathematical background material. Topics that include the action principle, weak gravitational fields and gravitational waves, Schwarzschild and Kerr solution, and the Friedman equation in cosmology. The book is suitable for advanced graduates and graduates, but also for established researchers wishing to be educated about the field.

  15. Gravitational neutron monochromator

    International Nuclear Information System (INIS)

    A new type of slow-neutron monochromator is described that is based on the interaction of slow neutrons with the earth's gravitational field. The monochromator is formed by three slit collimators placed along the neutron trajectory. The energy of the neutrons selected by the monochromator is set by vertical movement of any of the slit collimators. This scheme was used to create a gravitational monochromator on the 1000-meter path of the IBR-30 pulsed fast reactor at Dubna. It provides monochromatic neutrons with an energy resolution of 1.8% and measures the free-fall acceleration of neutrons with an error of 0.1% in the energy range of 0.0175-0.4223 eV

  16. 290 years of gravitation

    International Nuclear Information System (INIS)

    The origins of Newton's theory of gravitation are presented and its applications in celestial mechanics are discussed. The three-body problem and various attempts to solve it, and Sundman's solution, are also presented. The nature of gravitation is discussed, from Descartes' theory of elastic collisions, through the electromagnetic concepts culminating in Thomson's theoretical study, to special and general relativity. It is pointed out that, despite its successes, relativity theory is not of practical use. Almanacs and satellite orbits are calculated by Newtonian mechanics. Nor can relativity lead to a practical solution of the three-body problem. Finally the author maintains that the solutions to physical problems should be sought in numbers and not in geometry, and proposes an 'antigeometric algebra'. (JIW)

  17. COSMOLOGY WITH GRAVITATIONAL LENSES

    Directory of Open Access Journals (Sweden)

    Emilio E. Falco

    2009-01-01

    Full Text Available Gravitational lenses yield a very high rate of return on observational investment. Given their scarcity, their impact on our knowledge of the universe is very signi cant. In the weak- eld limit, lensing studies are based on well-established physics and thus o er a straightforward approach to pursue many currently pressing problems of astrophysics. Examples of these are the signi cance of dark matter and the density, age and size of the universe. I present recent developments in cosmological applications of gravitational lenses, regarding estimates of the Hubble constant using strong lensing of quasars. I describe our recent measurements of time delays for the images of SDSS J1004+4112, and discuss prospects for the future utilizing synoptic telescopes, planned and under construction.

  18. Gravitational lensing by wormholes

    OpenAIRE

    Dey, Tushar Kanti; Sen, Surajit

    2008-01-01

    We have investigated the gravitational lensing by two wormholes, viz., Janis-Newman-Winnicour (JNW) wormhole and Ellis wormhole. The deflection angle in the strong field limit is calculated and various lens parameters of two wormholes are compared. It is shown that the JNW wormhole exhibits the relativistic images, while the Ellis wormhole does not have any relativistic images due to the absence of its photon sphere.

  19. Gravitational Energy Control

    OpenAIRE

    De Aquino, Fran

    2015-01-01

    International audience This is a set of 59 selected articles published by Dr. Fran De Aquino along 16 years; all of them developed starting from the Relativistic Theory of Quantum Gravity (first article). Together they provide the theoretical foundations for the Technology of Control of the Gravitational Energy. The author is Professor Emeritus of Physics of Maranhao State University, UEMA, and Titular Researcher (R) of National Institute for Space Research, INPE.

  20. Neutrinos from gravitational collapse

    International Nuclear Information System (INIS)

    Detailed calculations are made of the neutrino spectra emitted during gravitational collapse events (Type II supernovae). Those aspects of the neutrino signal which are relatively independent of the collapse model and those aspects which are sensitive to model details are discussed. The easier-to-detect high energy tail of the emitted neutrinos has been calculated using the Boltzmann equation which is compared with the result of the traditional multi-group flux limited diffusion calculations. 8 figs., 28 refs

  1. What is Gravitation?

    OpenAIRE

    Patrick Das Gupta

    2009-01-01

    This article analyses the nature of classical Newtonian gravity beginning with Galileo's experiments and the paradox that ensues from Aristotle's law of falling bodies, delving on the notions of inertial and gravitational masses. Arguing that Newton's gravity law is inconsistent with relativity, it briefly describes Einstein's relativistic theory of gravity, pointing out the importance of weak equivalence principle in the formulation of general theory of relativity. It also provides a short d...

  2. Gravitational Wave Confusion Noise

    OpenAIRE

    Cornish, Neil J.

    2003-01-01

    One of the greatest challenges facing gravitational wave astronomy in the low frequency band is the confusion noise generated by the vast numbers of unresolved galactic and extra galactic binary systems. Estimates of the binary confusion noise suffer from several sources of astrophysical uncertainty, such as the form of the initial mass function and the star formation rate. There is also considerable uncertainty about what defines the confusion limit. Various ad-hoc rules have been proposed, ...

  3. Flux-limited strong gravitational lensing and dark energy

    CERN Document Server

    Chen, D M

    2004-01-01

    In the standard flat cosmological constant ($Lambda$) cold dark matter (CDM) cosmology, a model of two populations of lens halos for strong gravitational lensing can reproduce the results of the Jodrell-Bank VLA Astrometric Survey (JVAS) and the Cosmic Lens All-Sky Survey (CLASS) radio survey. In such a model, lensing probabilities are sensitive to three parameters: the concentration parameter $c_1$, the cooling mass scale $M_mathrm{c}$ and the value of the CDM power spectrum normalization parameter $sigma_8$. The value ranges of these parameters are constrained by various observations. However, we found that predicted lensing probabilities are also quite sensitive to the flux density (brightness) ratio $q_{mathrm{r}}$ of the multiple lensing images, which has been, in fact, a very important selection criterion of a sample in any lensing survey experiments. We re-examine the above mentioned model by considering the flux ratio and galactic central Super Massive Black Holes (SMBHs), in flat, low-density cosmolo...

  4. Electrostatic-gravitational oscillator

    CERN Document Server

    Vayenas, Constantinos G

    2009-01-01

    We examine the one-dimensional motion of two similarly charged particles under the influence of only two forces, i.e. their Coulombic repulsion and their gravitational attraction, using the relativistic equation of motion. We find that when the rest mass of the two particles is sufficiently small (~ 0.4 eV/c2) and the initial Coulombic potential energy is sufficiently high (~ mpc2, where mp is the proton mass), then the strong gravitational attraction resulting from the relativistic particle velocities suffices to counterbalance the Coulombic repulsion and to cause stable periodic motion of the two particles. The creation of this confined oscillatory state, with a rest mass equal to that of a proton, is shown to be consistent with quantum mechanics by examining the particle de Broglie wavelength and the Klein-Gordon and Schrodinger equations. It is shown that the gravitational constant can be expressed in terms of the proton mass and charge, the vacuum dielectric constant, the Planck constant and the speed of...

  5. Gravitational Waves Astronomy: a cornerstone for gravitational theories

    CERN Document Server

    Corda, Christian

    2010-01-01

    Realizing a gravitational wave (GW) astronomy in next years is a great challenge for the scientific community. By giving a significant amount of new information, GWs will be a cornerstone for a better understanding of gravitational physics. In this paper we re-discuss that the GW astronomy will permit to solve a captivating issue of gravitation. In fact, it will be the definitive test for Einstein's general relativity (GR), or, alternatively, a strong endorsement for extended theories of gravity (ETG).

  6. Anomalous Higgs Couplings at Colliders

    CERN Document Server

    González-Garciá, M Concepción

    1998-01-01

    I summarize our results on the attainable limits on the coefficients of dimension-6 operators from the analysis of Higgs boson phenomenology using data taken at Tevatron RUNI and LEPII. Our results show that the coefficients of Higgs-vector boson couplings can be determined with unprecedented accuracy. Assuming that the coefficients of all ``blind'' operators are of the same magnitude, we are also able to impose bounds on the anomalous vector-boson triple couplings comparable to those from double gauge boson production at the Tevatron and LEPII.

  7. Anomalous Hall effect in polycrystalline Ni films

    KAUST Repository

    Guo, Zaibing

    2012-02-01

    We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.

  8. Probing Positron Gravitation at HERA

    CERN Document Server

    Gharibyan, Vahagn

    2015-01-01

    An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)\\% weaker coupling to the gravitational field relative to an electron.

  9. Thought Experiments on Gravitational Forces

    OpenAIRE

    Lynden-Bell, Donald; Katz, Joseph

    2013-01-01

    Large contributions to the near closure of the Universe and to the acceleration of its expansion are due to the gravitation of components of the stress-energy tensor other than its mass density. To familiarise astronomers with the gravitation of these components we conduct thought experiments on gravity, analogous to the real experiments that our forebears conducted on electricity. By analogy to the forces due to electric currents we investigate the gravitational forces due to the flows of mo...

  10. Probing Positron Gravitation at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Gharibyan, Vahagn

    2015-07-15

    An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)% weaker coupling to the gravitational field relative to an electron.

  11. Quantum Emulation of Gravitational Waves

    OpenAIRE

    Ivan Fernandez-Corbaton; Mauro Cirio; Alexander Büse; Lucas Lamata; Enrique Solano; Gabriel Molina-Terriza

    2015-01-01

    Gravitational waves, as predicted by Einstein's general relativity theory, appear as ripples in the fabric of spacetime traveling at the speed of light. We prove that the propagation of small amplitude gravitational waves in a curved spacetime is equivalent to the propagation of a subspace of electromagnetic states. We use this result to propose the use of entangled photons to emulate the evolution of gravitational waves in curved spacetimes by means of experimental electromagnetic setups fea...

  12. Quantum Emulation of Gravitational Waves.

    Science.gov (United States)

    Fernandez-Corbaton, Ivan; Cirio, Mauro; Büse, Alexander; Lamata, Lucas; Solano, Enrique; Molina-Terriza, Gabriel

    2015-01-01

    Gravitational waves, as predicted by Einstein's general relativity theory, appear as ripples in the fabric of spacetime traveling at the speed of light. We prove that the propagation of small amplitude gravitational waves in a curved spacetime is equivalent to the propagation of a subspace of electromagnetic states. We use this result to propose the use of entangled photons to emulate the evolution of gravitational waves in curved spacetimes by means of experimental electromagnetic setups featuring metamaterials. PMID:26169801

  13. A discussion on the existence of the anomalous high and the anomalous low

    OpenAIRE

    Li, N

    2015-01-01

    The air flow in a three-way balance between the Coriolis force, the centrifugal force and the pressure gradient force, i.e., the gradient wind, is discussed. The author studies formation mechanisms and possible existence of four types of gradient wind (the normal high, the normal low, the anomalous high and the anomalous low), and proposes reasonable explanation of the evolution of the gradient wind, especially for the anomalous high and the anomalous low, both of which are ...

  14. Gravitational Waves from the Phase Transition of a Non-linearly Realised Electroweak Gauge Symmetry

    CERN Document Server

    Kobakhidze, Archil; Yue, Jason

    2016-01-01

    Within the Standard Model with non-linearly realised electroweak symmetry, the LHC Higgs boson may reside in a singlet representation of the gauge group. Several new interactions are then allowed, including anomalous Higgs self-couplings, which may drive the electroweak phase transition to be strongly first-order. In this paper we investigate the cosmological electroweak phase transition in a simplified model with an anomalous Higgs cubic self- coupling. We look at the feasibility of detecting gravitational waves produced during such a transition in the early universe by future space-based experiments. We find that for the range of relatively large cubic couplings, $111~{\\rm GeV}~ \\lesssim |\\kappa| \\lesssim 118~{\\rm GeV}$, $\\sim $mHz frequency gravitational waves can be observed by eLISA, while BBO will potentially be able to detect waves in a wider frequency range, $0.1-10~$mHz.

  15. On the Energy of Rotating Gravitational Waves

    OpenAIRE

    Mashhoon, Bahram; McClune, James C.; Chavez, Enrique; Quevedo, Hernando

    1996-01-01

    A class of solutions of the gravitational field equations describing vacuum spacetimes outside rotating cylindrical sources is presented. A subclass of these solutions corresponds to the exterior gravitational fields of rotating cylindrical systems that emit gravitational radiation. The properties of these rotating gravitational wave spacetimes are investigated. In particular, we discuss the energy density of these waves using the gravitational stress-energy tensor.

  16. Anomalous transport in toroidal plasmas

    International Nuclear Information System (INIS)

    When the magnetic moment of particle is conserved, there are three mechanisms which cause anomalous transport. These are: variation of magnetic field strength in flux surface, variation of electrostatic potential in flux surface, and destruction of flux surface. The anomalous transport of different groups of particles resulting from each of these mechanisms is different. This fact can be exploited to determine the cause of transport operative in an experimental situation. This approach can give far more information on the transport than the standard confinement time measurements. To implement this approach, we have developed Monte Carlo codes for toroidal geometries. The equations of motion are developed in a set of non-canonical, practical Boozer co-ordinates by means of Jacobian transformations of the particle drift Hamiltonian equations of motion. Effects of collisions are included by appropriate stochastic changes in the constants of motion. Effects of the loop voltage on particle motions are also included. We plan to apply our method to study two problems: the problem of the hot electron tail observed in edge region of ZT-40, and the energy confinement time in TOKAPOLE II. For the ZT-40 problem three situations will be considered: a single mode in the core, a stochastic region that covers half the minor radius, a stochastic region that covers the entire plasma. A turbulent spectrum of perturbations based on the experimental data of TOKAPOLE II will be developed. This will be used to simulate electron transport resulting from ideal instabilities and resistive instabilities in TOKAPOLE II

  17. The antimatter gravitational field

    CERN Document Server

    Chiarelli, Piero

    2015-01-01

    In this work the author derives the Galilean limit of the gravitational field of antimatter by using the hydrodynamic quantum gravity equations that comprehend the antiparticle impulse-energy tensor. The result shows that, even the antimatter mass is a positive valued quantity, its presence gives a negative 4-d space curvature respect to that one of the matter as a consequence of the backward propagation in time of the antimatter wave function. The result leads to the consequence that the null space curvature of photons undergoing to electron-positron couples generation (or annihilation) does not change during the process. A laboratory experiment to validate the theory output is also proposed .

  18. Gravitational Lensing & Stellar Dynamics

    CERN Document Server

    Koopmans, L V E

    2005-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-anisotropy degeneracies. Second, observational results are presented from the Lenses Structure & Dynamics (LSD) Survey and the Sloan Lens ACS (SLACS) Survey collaborations to illustrate this new methodology in constraining the dark and stellar density profiles, and mass structure, of early-type galaxies to redshifts of unity.

  19. Superstatistics and Gravitation

    Directory of Open Access Journals (Sweden)

    Octavio Obregón

    2010-09-01

    Full Text Available We suggest to consider the spacetime as a non-equilibrium system with a long-term stationary state that possess as a spatio-temporally fluctuating quantity ß . These systems can be described by a superposition of several statistics, superstatistics. We propose a Gamma distribution for f(ß that depends on a parameter ρ1. By means of it the corresponding entropy is calculated, ρ1 is identified with the probability corresponding to this model. A generalized Newton’s law of gravitation is then obtained following the entropic force formulation. We discuss some of the difficulties to try to get an associated theory of gravity.

  20. General Relativity and Gravitation

    Science.gov (United States)

    Ashtekar, Abhay; Berger, Beverly; Isenberg, James; MacCallum, Malcolm

    2015-07-01

    Part I. Einstein's Triumph: 1. 100 years of general relativity George F. R. Ellis; 2. Was Einstein right? Clifford M. Will; 3. Cosmology David Wands, Misao Sasaki, Eiichiro Komatsu, Roy Maartens and Malcolm A. H. MacCallum; 4. Relativistic astrophysics Peter Schneider, Ramesh Narayan, Jeffrey E. McClintock, Peter Mészáros and Martin J. Rees; Part II. New Window on the Universe: 5. Receiving gravitational waves Beverly K. Berger, Karsten Danzmann, Gabriela Gonzalez, Andrea Lommen, Guido Mueller, Albrecht Rüdiger and William Joseph Weber; 6. Sources of gravitational waves. Theory and observations Alessandra Buonanno and B. S. Sathyaprakash; Part III. Gravity is Geometry, After All: 7. Probing strong field gravity through numerical simulations Frans Pretorius, Matthew W. Choptuik and Luis Lehner; 8. The initial value problem of general relativity and its implications Gregory J. Galloway, Pengzi Miao and Richard Schoen; 9. Global behavior of solutions to Einstein's equations Stefanos Aretakis, James Isenberg, Vincent Moncrief and Igor Rodnianski; Part IV. Beyond Einstein: 10. Quantum fields in curved space-times Stefan Hollands and Robert M. Wald; 11. From general relativity to quantum gravity Abhay Ashtekar, Martin Reuter and Carlo Rovelli; 12. Quantum gravity via unification Henriette Elvang and Gary T. Horowitz.

  1. The Gravitational Universe

    CERN Document Server

    Danzmann, K

    2013-01-01

    The last century has seen enormous progress in our understanding of the Universe. We know the life cycles of stars, the structure of galaxies, the remnants of the big bang, and have a general understanding of how the Universe evolved. We have come remarkably far using electromagnetic radiation as our tool for observing the Universe. However, gravity is the engine behind many of the processes in the Universe, and much of its action is dark. Opening a gravitational window on the Universe will let us go further than any alternative. Gravity has its own messenger: Gravitational waves, ripples in the fabric of spacetime. They travel essentially undisturbed and let us peer deep into the formation of the first seed black holes, exploring redshifts as large as z ~ 20, prior to the epoch of cosmic re-ionisation. Exquisite and unprecedented measurements of black hole masses and spins will make it possible to trace the history of black holes across all stages of galaxy evolution, and at the same time constrain any devia...

  2. Non-Anomalous Semigroups and Real Numbers

    OpenAIRE

    Binder, Damon

    2016-01-01

    Motivated by intuitive properties of physical quantities, the notion of a non-anomalous semigroup is formulated. These are totally ordered semigroups where there are no `infinitesimally close' elements. The real numbers are then defined as the terminal object in a closely related category. From this definition a field structure on $\\mathbb R$ is derived, relating multiplication to morphisms between non-anomalous semigroups.

  3. Anomalous commutator corrections to sum rules

    International Nuclear Information System (INIS)

    In this paper we consider the contributions of anomalous commutators to various QCD sum rules. Using a combination of the Bjorken-Johnson-Low limit with the operator product expansion the results are presented in terms of the vacuum condensates of gauge-invariant operators. It is demonstrated that the anomalous contributions are non-negligible and reconcile various apparently contradictory calculations

  4. Anomalous transport at weak coupling

    CERN Document Server

    Chowdhury, Subham Dutta

    2015-01-01

    We evaluate the contribution of chiral fermions in $d=2, 4, 6$, chiral bosons, a chiral gravitino like theory in $d=2$ and chiral gravitinos in $d=6$ to all the leading parity odd transport coefficients at one loop. This is done by using finite temperature field theory to evaluate the relevant Kubo formulae. For chiral fermions and chiral bosons the relation between the parity odd transport coefficient and the microscopic anomalies including gravitational anomalies agree with that found by using the general methods of hydrodynamics and the argument involving the consistency of the Euclidean vacuum. For the gravitino like theory in $d=2$ and chiral gravitinos in $d=6$, we show that relation between the pure gravitational anomaly and parity odd transport breaks down. From the perturbative calculation we clearly identify the terms that contribute to the anomaly polynomial, but not to the transport coefficient for gravitinos. We also develop a simple method for evaluating the angular integrals in the one loop dia...

  5. Exact piecewise flat gravitational waves

    NARCIS (Netherlands)

    van de Meent, M.

    2011-01-01

    We generalize our previous linear result (van de Meent 2011 Class. Quantum Grav 28 075005) in obtaining gravitational waves from our piecewise flat model for gravity in 3+1 dimensions to exact piecewise flat configurations describing exact planar gravitational waves. We show explicitly how to constr

  6. Critical Effects in Gravitational Collapse

    International Nuclear Information System (INIS)

    The models of gravitational collapse of a dynamical system are investigated by means of the Einstein equations. Different types conjunctions to gravitational field are analyzed and it is shown that in the case of week scalar field (low energy density) the system evaluated to flat space while in the case of strong field (high energy density) to black hole

  7. Momentum Imparted by Gravitational Waves

    OpenAIRE

    Sharif, M.

    2003-01-01

    We calculate momentum imparted by colliding gravitational waves in a closed Friedmann Robertson-Walker background and also by gravitational waves with toroidal wavefronts using an operational procedure. The results obtained for toroidal wavefronts are well behaved and reduce to the spherical wavefronts for a special choice.

  8. Generating Gravitational Waves After Inflation

    OpenAIRE

    Easther, Richard

    2009-01-01

    I review two mechanisms by which gravitational waves can be generated at the end of inflation: preheating, and gravitons Hawking radiated during the decay of very small primordial black holes. These mechanisms are contrasted with the gravitational waves during inflation, and may provide a window into the physical processes that govern the end of the inflationary phase.

  9. Exact Piecewise Flat Gravitational Waves

    OpenAIRE

    van de Meent, Maarten

    2011-01-01

    We generalize our previous linear result [1] in obtaining gravitational waves from our piecewise flat model for gravity in 3+1 dimensions to exact piecewise flat configurations describing exact planar gravitational waves. We show explicitly how to construct a piecewise flat spacetime that describes an impulsive plane wavefront. From these wavefronts more general plane waves may be constructed.

  10. Gravitational Wave for a pedestrian

    CERN Document Server

    Chaudhuri, A K

    2016-01-01

    The physics of gravitational wave and its detection in the recent experiment by the LIGO collaboration is discussed in simple terms for a general audience. The main article is devoid of any mathematics, but an appendix is included for inquisitive readers where essential mathematics for general theory of relativity and gravitational waves are given.

  11. The gravitational properties of antimatter

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, T.; Hughes, R.J.; Nieto, M.M.

    1986-09-01

    It is argued that a determination of the gravitational acceleration of antimatter towards the earth is capable of imposing powerful constraints on modern quantum gravity theories. Theoretical reasons to expect non-Newtonian non-Einsteinian effects of gravitational strength and experimental suggestions of such effects are reviewed. 41 refs. (LEW)

  12. The gravitational properties of antimatter

    International Nuclear Information System (INIS)

    It is argued that a determination of the gravitational acceleration of antimatter towards the earth is capable of imposing powerful constraints on modern quantum gravity theories. Theoretical reasons to expect non-Newtonian non-Einsteinian effects of gravitational strength and experimental suggestions of such effects are reviewed. 41 refs

  13. Unification of Electromagnetism and Gravitation

    CERN Document Server

    Shahverdiyev, S S

    2002-01-01

    We propose a unified model of electromagnetism and gravitation in the framework of General Geometry. It reproduces Electromagnetism and General Relativity and predicts that electromagnetic field is a source for gravitational field. This theory is formulated in four dimensional spacetime and does not contain additional fields.

  14. To theory of gravitational interaction

    OpenAIRE

    Minkevich, A. V.

    2008-01-01

    Some principal problems of general relativity theory and attempts of their solution are discussed. The Poincare gauge theory of gravity as natural generalization of Einsteinian gravitation theory is considered. The changes of gravitational interaction in the frame of this theory leading to the solution of principal problems of general relativity theory are analyzed.

  15. Vignettes in Gravitation and Cosmology

    CERN Document Server

    Sriramkumar, L

    2012-01-01

    This book comprises expository articles on different aspects of gravitation and cosmology that are aimed at graduate students. The topics discussed are of contemporary interest assuming only an elementary introduction to gravitation and cosmology. The presentations are to a certain extent pedagogical in nature, and the material developed is not usually found in sufficient detail in recent textbooks in these areas.

  16. Anomalous diffraction in hyperbolic materials

    CERN Document Server

    Alberucci, Alessandro; Boardman, Allan D; Assanto, Gaetano

    2016-01-01

    We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, spatial analogue of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.

  17. Soft theorems from anomalous symmetries

    CERN Document Server

    Huang, Yu-tin

    2015-01-01

    We discuss constraints imposed by soft limits for effective field theories arising from symmetry breaking. In particular, we consider those associated with anomalous conformal symmetry as well as duality symmetries in supergravity. We verify these soft theorems for the dilaton effective action relevant for the a-theorem, as well as the one-loop effective action for N=4 supergravity. Using the universality of leading transcendental coefficients in the alpha' expansion of string theory amplitudes, we study the matrix elements of operator R^4 with half maximal supersymmetry. We construct the non-linear completion of R^4 that satisfies both single and double soft theorems up to seven points. This supports the existence of duality invariant completion of R^4.

  18. Anomalous Growth of Aging Populations

    Science.gov (United States)

    Grebenkov, Denis S.

    2016-04-01

    We consider a discrete-time population dynamics with age-dependent structure. At every time step, one of the alive individuals from the population is chosen randomly and removed with probability q_k depending on its age, whereas a new individual of age 1 is born with probability r. The model can also describe a single queue in which the service order is random while the service efficiency depends on a customer's "age" in the queue. We propose a mean field approximation to investigate the long-time asymptotic behavior of the mean population size. The age dependence is shown to lead to anomalous power-law growth of the population at the critical regime. The scaling exponent is determined by the asymptotic behavior of the probabilities q_k at large k. The mean field approximation is validated by Monte Carlo simulations.

  19. The spectrum of anomalous magnetohydrodynamics

    CERN Document Server

    Giovannini, Massimo

    2016-01-01

    The equations of anomalous magnetohydrodynamics describe an Abelian plasma where conduction and chiral currents are simultaneously present and constrained by the second law of thermodynamics. At high frequencies the magnetic currents play the leading role and the spectrum is dominated by two-fluid effects. The system behaves instead as a single fluid in the low-frequency regime where the vortical currents induce potentially large hypermagnetic fields. After deriving the physical solutions of the generalized Appleton-Hartree equation, the corresponding dispersion relations are scrutinized and compared with the results valid for cold plasmas. Hypermagnetic knots and fluid vortices can be concurrently present at very low frequencies and suggest a qualitatively different dynamics of the hydromagnetic nonlinearities.

  20. Canonical proper time quantum gravitation

    Science.gov (United States)

    Lindesay, James

    2015-05-01

    At the root of the tensions involved in modeling the quantum dynamics of gravitating systems are the subtleties of quantum locality. Quantum mechanics describes physical phenomena using a theory of non-local phase relationships (non-local in the sense that quantum states maintain a space-like coherence that is acausal). However, the principle of equivalence in general relativity asserts that freely falling frames are locally inertial frames of reference. Thus, gravitating systems are often described using constituents that are freely falling, undergoing geodesic motion defining well localized trajectories. The canonical proper time formulation of relativistic dynamics is particularly useful for describing such inertial constituents using the coordinates of non-inertial observers. The physics of the simplest of gravitating inertial quantum systems, consistent with presented experimental evidence, will be examined. Subsequently, descriptions of both weakly and strongly gravitating quantum systems will be developed using canonical proper gravitation.

  1. Gravitational Repulsion and Dirac Antimatter

    Science.gov (United States)

    Kowitt, Mark E.

    1996-03-01

    Based on an analogy with electron and hole dynamics in semiconductors, Dirac's relativistic electron equation is generalized to include a gravitational interaction using an electromagnetic-type approximation of the gravitational potential. With gravitational and inertial masses decoupled, the equation serves to extend Dirac's deduction of antimatter parameters to include the possibility of gravitational repulsion between matter and antimatter. Consequences for general relativity and related “antigravity” issues are considered, including the nature and gravitational behavior of virtual photons, virtual pairs, and negative-energy particles. Basic cosmological implications of antigravity are explored—in particular, potential contributions to inflation, expansion, and the general absence of detectable antimatter. Experimental and observational tests are noted, and new ones suggested.

  2. Anomalous extracellular diffusion in rat cerebellum.

    Science.gov (United States)

    Xiao, Fanrong; Hrabe, Jan; Hrabetova, Sabina

    2015-05-01

    Extracellular space (ECS) is a major channel transporting biologically active molecules and drugs in the brain. Diffusion-mediated transport of these substances is hindered by the ECS structure but the microscopic basis of this hindrance is not fully understood. One hypothesis proposes that the hindrance originates in large part from the presence of dead-space (DS) microdomains that can transiently retain diffusing molecules. Because previous theoretical and modeling work reported an initial period of anomalous diffusion in similar environments, we expected that brain regions densely populated by DS microdomains would exhibit anomalous extracellular diffusion. Specifically, we targeted granular layers (GL) of rat and turtle cerebella that are populated with large and geometrically complex glomeruli. The integrative optical imaging (IOI) method was employed to evaluate diffusion of fluorophore-labeled dextran (MW 3000) in GL, and the IOI data analysis was adapted to quantify the anomalous diffusion exponent dw from the IOI records. Diffusion was significantly anomalous in rat GL, where dw reached 4.8. In the geometrically simpler turtle GL, dw was elevated but not robustly anomalous (dw = 2.6). The experimental work was complemented by numerical Monte Carlo simulations of anomalous ECS diffusion in several three-dimensional tissue models containing glomeruli-like structures. It demonstrated that both the duration of transiently anomalous diffusion and the anomalous exponent depend on the size of model glomeruli and the degree of their wrapping. In conclusion, we have found anomalous extracellular diffusion in the GL of rat cerebellum. This finding lends support to the DS microdomain hypothesis. Transiently anomalous diffusion also has a profound effect on the spatiotemporal distribution of molecules released into the ECS, especially at diffusion distances on the order of a few cell diameters, speeding up short-range diffusion-mediated signals in less permeable

  3. Gravitational Anomalies in the Solar System?

    CERN Document Server

    Iorio, Lorenzo

    2014-01-01

    Mindful of the anomalous perihelion precession of Mercury discovered by U. Le Verrier in the second half of the nineteenth century and its successful explanation by A. Einstein with his General Theory of Relativity in the early years of the twentieth century, discrepancies among observed effects in our Solar system and their theoretical predictions on the basis of the currently accepted laws of gravitation applied to known bodies have the potential of paving the way for remarkable advances in fundamental physics. This is particularly important now more than ever, given that most of the Universe seems to be made of unknown substances dubbed Dark Matter and Dark Energy. Should this not be directly the case, Solar system's anomalies could anyhow lead to advancements in cumulative science, as shown to us by the discovery of Neptune in the first half of the nineteenth century. Moreover, investigations in one of such directions can serendipitously enrich the other one as well. The current status of some alleged gra...

  4. Gravitational anomalies and one-dimensional behavior of black holes

    Energy Technology Data Exchange (ETDEWEB)

    Majhi, Bibhas Ranjan, E-mail: bibhas.majhi@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, 781039, Guwahati, Assam (India)

    2015-12-08

    It has been pointed out by Bekenstein and Mayo that the behavior of the black hole’s entropy or information flow is similar to information flow through one-dimensional channel. Here I analyze the same issue with the use of gravitational anomalies. The rate of the entropy change (S{sup .}) and the power (P) of the Hawking emission are calculated from the relevant components of the anomalous stress tensor under the Unruh vacuum condition. I show that the dependence of S{sup .} on the power is S{sup .} ∝P{sup 1/2}, which is identical to that for the information flow in a one-dimensional system. This is established by using the (1+1)-dimensional gravitational anomalies first. Then the fact is further bolstered by considering the (1+3)-dimensional gravitational anomalies. It is found that, in the former case, the proportionality constant is exactly identical to the one-dimensional situation, known as Pendry’s formula, while in the latter situation its value decreases.

  5. Gravitational anomalies and one-dimensional behavior of black holes

    Energy Technology Data Exchange (ETDEWEB)

    Majhi, Bibhas Ranjan [Indian Institute of Technology Guwahati, Department of Physics, Guwahati, Assam (India)

    2015-12-15

    It has been pointed out by Bekenstein and Mayo that the behavior of the black hole's entropy or information flow is similar to information flow through one-dimensional channel. Here I analyze the same issue with the use of gravitational anomalies. The rate of the entropy change (S) and the power (P) of the Hawking emission are calculated from the relevant components of the anomalous stress tensor under the Unruh vacuum condition. I show that the dependence of S on the power is S ∝ P{sup 1/2}, which is identical to that for the information flow in a one-dimensional system. This is established by using the (1+1)-dimensional gravitational anomalies first. Then the fact is further bolstered by considering the (1+3)-dimensional gravitational anomalies. It is found that, in the former case, the proportionality constant is exactly identical to the one-dimensional situation, known as Pendry's formula, while in the latter situation its value decreases. (orig.)

  6. Gravitational anomalies and one-dimensional behavior of black holes

    International Nuclear Information System (INIS)

    It has been pointed out by Bekenstein and Mayo that the behavior of the black hole’s entropy or information flow is similar to information flow through one-dimensional channel. Here I analyze the same issue with the use of gravitational anomalies. The rate of the entropy change (S.) and the power (P) of the Hawking emission are calculated from the relevant components of the anomalous stress tensor under the Unruh vacuum condition. I show that the dependence of S. on the power is S. ∝P1/2, which is identical to that for the information flow in a one-dimensional system. This is established by using the (1+1)-dimensional gravitational anomalies first. Then the fact is further bolstered by considering the (1+3)-dimensional gravitational anomalies. It is found that, in the former case, the proportionality constant is exactly identical to the one-dimensional situation, known as Pendry’s formula, while in the latter situation its value decreases

  7. Gravitational anomalies and one-dimensional behavior of black holes

    International Nuclear Information System (INIS)

    It has been pointed out by Bekenstein and Mayo that the behavior of the black hole's entropy or information flow is similar to information flow through one-dimensional channel. Here I analyze the same issue with the use of gravitational anomalies. The rate of the entropy change (S) and the power (P) of the Hawking emission are calculated from the relevant components of the anomalous stress tensor under the Unruh vacuum condition. I show that the dependence of S on the power is S ∝ P1/2, which is identical to that for the information flow in a one-dimensional system. This is established by using the (1+1)-dimensional gravitational anomalies first. Then the fact is further bolstered by considering the (1+3)-dimensional gravitational anomalies. It is found that, in the former case, the proportionality constant is exactly identical to the one-dimensional situation, known as Pendry's formula, while in the latter situation its value decreases. (orig.)

  8. Solar rotation gravitational moments

    Directory of Open Access Journals (Sweden)

    A. Ajabshirizadeh

    2005-09-01

    Full Text Available   Gravitational multipole moments of the Sun are still poorly known. Theoretically, the difficulty is mainly due to the differential rotation for which the velocity rate varies both on the surface and with the depth. From an observational point of view, the multipole moments cannot be directly measured. However, recent progresses have been made proving the existence of a strong radial differential rotation in a thin layer near the solar surface (the leptocline. Applying the theory of rotating stars, we will first compute values of J2 and J4 taking into account the radial gradient of rotation, then we will compare these values with the existing ones, giving a more complete review. We will explain some astrophysical outcomes, mainly on the relativistic Post Newtonian parameters. Finally we will conclude by indicating how space experiments (balloon SDS flights, Golf NG, Beppi-Colombo, Gaia... will be essential to unambiguously determine these parameters.

  9. Feynman Lectures on Gravitation

    International Nuclear Information System (INIS)

    In the early 1960s Feynman lectured to physics undergraduates and, with the assistance of his colleagues Leighton and Sands, produced the three-volume classic Feynman Lectures in Physics. These lectures were delivered in the mornings. In the afternoons Feynman was giving postgraduate lectures on gravitation. This book is based on notes compiled by two students on that course: Morinigo and Wagner. Their notes were checked and approved by Feynman and were available at Caltech. They have now been edited by Brian Hatfield and made more widely available. The book has a substantial preface by John Preskill and Kip Thorne, and an introduction entitled 'Quantum Gravity' by Brian Hatfield. You should read these before going on to the lectures themselves. Preskill and Thorne identify three categories of potential readers of this book. 1. Those with a postgraduate training in theoretical physics. 2. 'Readers with a solid undergraduate training in physics'. 3. 'Admirers of Feynman who do not have a strong physics background'. The title of the book is perhaps misleading: readers in category 2 who think that this book is an extension of the Feynman Lectures in Physics may be disappointed. It is not: it is a book aimed mainly at those in category 1. If you want to get to grips with gravitation (and general relativity) then you need to read an introductory text first e.g. General Relativity by I R Kenyon (Oxford: Oxford University Press) or A Unified Grand Tour of Theoretical Physics by Ian D Lawrie (Bristol: IoP). But there is no Royal Road. As pointed out in the preface and in the introduction, the book represents Feynman's thinking about gravitation some 40 years ago: the lecture course was part of his attempts to understand the subject himself, and for readers in all three categories it is this that makes the book one of interest: the opportunity to observe how a great physicist attempts to tackle some of the hardest challenges of physics. However, the book was written 40

  10. Feynman Lectures on Gravitation

    Energy Technology Data Exchange (ETDEWEB)

    Borcherds, P

    2003-05-21

    In the early 1960s Feynman lectured to physics undergraduates and, with the assistance of his colleagues Leighton and Sands, produced the three-volume classic Feynman Lectures in Physics. These lectures were delivered in the mornings. In the afternoons Feynman was giving postgraduate lectures on gravitation. This book is based on notes compiled by two students on that course: Morinigo and Wagner. Their notes were checked and approved by Feynman and were available at Caltech. They have now been edited by Brian Hatfield and made more widely available. The book has a substantial preface by John Preskill and Kip Thorne, and an introduction entitled 'Quantum Gravity' by Brian Hatfield. You should read these before going on to the lectures themselves. Preskill and Thorne identify three categories of potential readers of this book. 1. Those with a postgraduate training in theoretical physics. 2. 'Readers with a solid undergraduate training in physics'. 3. 'Admirers of Feynman who do not have a strong physics background'. The title of the book is perhaps misleading: readers in category 2 who think that this book is an extension of the Feynman Lectures in Physics may be disappointed. It is not: it is a book aimed mainly at those in category 1. If you want to get to grips with gravitation (and general relativity) then you need to read an introductory text first e.g. General Relativity by I R Kenyon (Oxford: Oxford University Press) or A Unified Grand Tour of Theoretical Physics by Ian D Lawrie (Bristol: IoP). But there is no Royal Road. As pointed out in the preface and in the introduction, the book represents Feynman's thinking about gravitation some 40 years ago: the lecture course was part of his attempts to understand the subject himself, and for readers in all three categories it is this that makes the book one of interest: the opportunity to observe how a great physicist attempts to tackle some of the hardest challenges of physics

  11. New cylindrical gravitational soliton waves and gravitational Faraday rotation

    CERN Document Server

    Tomizawa, Shinya

    2013-01-01

    In terms of gravitational solitons, we study gravitational non-linear effects of gravitational solitary waves such as Faraday rotation. Applying the Pomeransky's procedure for inverse scattering method, which has been recently used for constructing stationary black hole solutions in five dimensions to a cylindrical spacetime in four dimensions, we construct a new cylindrically symmetric soliton solution. This is the first example to be applied to the cylindrically symmetric case. In particular, we clarify the difference from the Tomimatsu's single soliton solution, which was constructed by the Belinsky-Zakharov's procedure.

  12. The Anomalous Scaling Exponents of Turbulence in General Dimension from Random Geometry

    CERN Document Server

    Eling, Christopher

    2015-01-01

    We propose an exact analytical formula for the anomalous scaling exponents of inertial range structure functions in incompressible fluid turbulence. The formula is a gravitational Knizhnik-Polyakov-Zamolodchikov (KPZ)-type relation, and is valid in any number of space dimensions. It incorporates intermittency by gravitationally dressing the Kolmogorov linear scaling via a coupling to a random geometry. The formula has one real parameter $\\gamma$ that depends on the number of space dimensions. The scaling exponents satisfy the convexity inequality, and the supersonic bound constraint. They agree with the experimental and numerical data in two and three space dimensions, and with numerical data in four space dimensions. Intermittency increases with $\\gamma$, and in the infinite $\\gamma$ limit the scaling exponents approach the value one, as in Burgers turbulence. At large $n$ the $n$th order exponent scales as $\\sqrt{n}$. We apply the formula to the Kraichnan model for passive scalar advection by a random veloc...

  13. Weight, gravitation, inertia, and tides

    Science.gov (United States)

    Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe

    2015-11-01

    This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix.

  14. Anomalous dispersion enhanced Cerenkov phase-matching

    Energy Technology Data Exchange (ETDEWEB)

    Kowalczyk, T.C.; Singer, K.D. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Physics; Cahill, P.A. [Sandia National Labs., Albuquerque, NM (United States)

    1993-11-01

    The authors report on a scheme for phase-matching second harmonic generation in polymer waveguides based on the use of anomalous dispersion to optimize Cerenkov phase matching. They have used the theoretical results of Hashizume et al. and Onda and Ito to design an optimum structure for phase-matched conversion. They have found that the use of anomalous dispersion in the design results in a 100-fold enhancement in the calculated conversion efficiency. This technique also overcomes the limitation of anomalous dispersion phase-matching which results from absorption at the second harmonic. Experiments are in progress to demonstrate these results.

  15. Supersymmetric Self-Gravitating Solitons

    CERN Document Server

    Gibbons, G W; London, L A J; Townsend, P K; Traschen, J

    1994-01-01

    We show that the `instantonic' soliton of five-dimensional Yang-Mills theory and the closely related BPS monopole of four-dimensional Yang-Mills/Higgs theory continue to be exact static, and stable, solutions of these field theories even after the inclusion of gravitational, electromagnetic and, in the four-dimensional case, dilatonic interactions, provided that certain non-minimal interactions are included. With the inclusion of these interactions, which would be required by supersymmetry, these exact self-gravitating solitons saturate a gravitational version of the Bogomol'nyi bound on the energy of an arbitrary field configuration.

  16. Phonon creation by gravitational waves

    International Nuclear Information System (INIS)

    We show that gravitational waves create phonons in a Bose-Einstein condensate (BEC). A traveling spacetime distortion produces particle creation resonances that correspond to the dynamical Casimir effect in a BEC phononic field contained in a cavity-type trap. We propose to use this effect to detect gravitational waves. The amplitude of the wave can be estimated applying recently developed relativistic quantum metrology techniques. We provide the optimal precision bound on the estimation of the wave's amplitude. Finally, we show that the parameter regime required to detect gravitational waves with this technique could be, in principle, within experimental reach in a medium-term timescale. (paper)

  17. Phonon creation by gravitational waves

    CERN Document Server

    Sabín, Carlos; Ahmadi, Mehdi; Fuentes, Ivette

    2014-01-01

    We show that gravitational waves create phonons in a Bose-Einstein condensate (BEC). A traveling spacetime distortion produces particle creation resonances that correspond to the dynamical Casimir effect in a BEC phononic field contained in a cavity-type trap. We propose to use this effect to detect gravitational waves. The amplitude of the wave can be estimated applying recently developed relativistic quantum metrology techniques. We provide the optimal precision bound on the estimation of the wave's amplitude. Finally, we show that the parameter regime required to detect gravitational waves with this technique is within experimental reach.

  18. Gravitation. [Book on general relativity

    Science.gov (United States)

    Misner, C. W.; Thorne, K. S.; Wheeler, J. A.

    1973-01-01

    This textbook on gravitation physics (Einstein's general relativity or geometrodynamics) is designed for a rigorous full-year course at the graduate level. The material is presented in two parallel tracks in an attempt to divide key physical ideas from more complex enrichment material to be selected at the discretion of the reader or teacher. The full book is intended to provide competence relative to the laws of physics in flat space-time, Einstein's geometric framework for physics, applications with pulsars and neutron stars, cosmology, the Schwarzschild geometry and gravitational collapse, gravitational waves, experimental tests of Einstein's theory, and mathematical concepts of differential geometry.

  19. Gravitational waves from hyperbolic encounters

    CERN Document Server

    Capozziello, S; De Paolis, F; Ingrosso, G; Nucita, A

    2008-01-01

    The emission of gravitational waves from a system of massive objects interacting on hyperbolic orbits is studied in the quadrupole approximation. Analytic expressions are derived for the gravitational radiation luminosity, the total energy output and the gravitational radiation amplitude. An estimation of the expected number of events towards different targets (i.e. globular clusters and the center of the Galaxy) is also given. In particular, for a dense stellar cluster at the galactic center, a rate up to one event per year is obtained.

  20. An overview of gravitational physiology

    Science.gov (United States)

    Miquel, Jaime; Souza, Kenneth A.

    1991-01-01

    The focus of this review is on the response of humans and animals to the effects of the near weightless condition occurring aboard orbiting spacecraft. Gravity is an omnipresent force that has been a constant part of our lives and of the evolution of all living species. Emphasis is placed on the general mechanisms of adaptation to altered gravitational fields and vectors, i.e., both hypo- and hypergravity. A broad literature review of gravitational biology was conducted and the general state of our knowledge in this area is discussed. The review is specifically targeted at newcomers to the exciting and relatively new area of space and gravitational biology.

  1. Gravitational effects of global textures

    International Nuclear Information System (INIS)

    A solution for the dynamics of global textures is obtained. Their gravitational field during the collapse and the subsequent evolution is found to be given solely by a space-time dependent ''deficit solid angle.'' The frequency shift of photons traversing this gravitational field is calculated. The space-time dependent texture metric locally contracts the volume of three-space and thereby induces overdensities in homogeneous matter distributions. There are no gravitational forces unless matter has a nonzero angular momentum with respect to the texture origin which would be the case for moving textures

  2. Gravitational Wave - Gauge Field Oscillations

    CERN Document Server

    Caldwell, R R; Maksimova, N A

    2016-01-01

    Gravitational waves propagating through a stationary gauge field transform into gauge field waves and back again. When multiple families of flavor-space locked gauge fields are present, the gravitational and gauge field waves exhibit novel dynamics. At high frequencies, the system behaves like coupled oscillators in which the gravitational wave is the central pacemaker. Due to energy conservation and exchange among the oscillators, the wave amplitudes lie on a multi-dimensional sphere, reminiscent of neutrino flavor oscillations. This phenomenon has implications for cosmological scenarios based on flavor-space locked gauge fields.

  3. The faintest radio source yet: EVLA observations of the gravitational lens SDSS J1004+4112

    CERN Document Server

    Jackson, Neal

    2011-01-01

    We present new radio observations of the large-separation gravitationally-lensed quasar SDSS J1004+4112, taken in a total of 6 hours of observations with the Extended Very Large Array (EVLA). The maps reach a thermal noise level of approximately 4microJy. We detect four of the five lensed images at the 15-35microJy level, representing a source of intrinsic flux density, after allowing for lensing magnification, of about 1microJy, intrinsically probably the faintest radio source yet detected. This reinforces the utility of gravitational lensing in potentially allowing us to study nanoJy-level sources before the advent of the SKA. In an optical observation taken three months after the radio observation, image C is the brightest image, whereas the radio map shows flux density ratios consistent with previous optical observations. Future observations separated by a time delay will give the intrinsic flux ratios of the images in this source.

  4. Gravitation toward Walls among Human Subjects

    Science.gov (United States)

    Dabbs, James M., Jr.; Wheeler, Patricia A.

    1976-01-01

    In two studies, college students (N=34) in a classroom corridor who walked near the wall ("gravitators") were contrasted with those who walked near the center ("non-gravitators"). Gravitators were lower than non-gravitators on Autonomy and Defendence and appeared to be less responsive to other persons. (Author)

  5. Testing local Lorentz invariance with gravitational waves

    Science.gov (United States)

    Kostelecký, V. Alan; Mewes, Matthew

    2016-06-01

    The effects of local Lorentz violation on dispersion and birefringence of gravitational waves are investigated. The covariant dispersion relation for gravitational waves involving gauge-invariant Lorentz-violating operators of arbitrary mass dimension is constructed. The chirp signal from the gravitational-wave event GW150914 is used to place numerous first constraints on gravitational Lorentz violation.

  6. Testing local Lorentz invariance with gravitational waves

    OpenAIRE

    Kostelecky, Alan; Mewes, Matthew

    2016-01-01

    The effects of local Lorentz violation on dispersion and birefringence of gravitational waves are investigated. The covariant dispersion relation for gravitational waves involving gauge-invariant Lorentz-violating operators of arbitrary mass dimension is constructed. The chirp signal from the gravitational-wave event GW150914 is used to place numerous first constraints on gravitational Lorentz violation.

  7. High frequency sources of gravitational waves

    OpenAIRE

    Kokkotas, Kostas D.

    2003-01-01

    Sources of high frequency gravitational waves are reviewed. Gravitational collapse, rotational instabilities and oscillations of the remnant compact objects are potentially important sources of gravitational waves. Significant and unique information for the various stages of the collapse, the evolution of protoneutron stars and the details of the equations of state of such objects can be drawn from careful study of the gravitational wave signal.

  8. Considerations on Gravitational Wave in Economics

    OpenAIRE

    Ovidiu Racorean

    2002-01-01

    A proposal for a dynamical potential of population displacements (named gravitational potential) between economic regions will be given. For a particular ideal chosen case,the gravitational potential is acting as a wave. An equation of the wave form will be given for gravitational potential-gravitational wave in economics.

  9. Quantum Opportunities in Gravitational Wave Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mavalvala, Negris (MIT)

    2012-03-14

    Direct observation of gravitational waves should open a new window into the Universe. Gravitational wave detectors are the most sensitive position meters ever constructed. The quantum limit in gravitational wave detectors opens up a whole new field of study. Quantum opportunities in gravitational wave detectors include applications of quantum optics techniques and new tools for quantum measurement on truly macroscopic (human) scales.

  10. Gravitational lensing in observational cosmology

    Science.gov (United States)

    Nottale, L.

    amplification of Brightest Cluster Galaxies by foreground clusters are analysed, including the discussion of a selection effect precisely due to gravitational luminosity amplification. It results in an artificial increase of the deceleration parameter of the Universe measured from the Hubble diagram of these objects. We recall our proposal that the sample of distant 3C radiogalaxies of redshift > 1 is strongly perturbed by lensing effects, mostly by foreground clusters of galaxies (i.e. only the luminosity is changed without image multiplication), but also for some objects by galaxies, producing gravitational mirages. The case of 3C324, for which definite evidence for multiple imaging has been recently obtained, is described, including detailed modelling of the lensing configuration. We present a highly significant statistical effect of lensing on absorption line QSOs due to matter lying at the absorption redshifts. Microlensing is also considered, and we recall our recent proposal that the variability of some among the OVV QSOs turning to BL Lac at maximum brightness, like the eruptive object 0846 +51W1, is a consequence of microlensing by stars or compact objects constituting foreground galaxy halos. Finally, discrepant redshift associations are considered. We recall how the case of anomalous quintets of galaxies have been explained by the gravitational lensing effects of quartets halos on background galaxies. Then we present evidence that the Arp QSO-galaxy associations may be the result of the combined lensing effects of several superposed galaxies, groups and clusters. Cet article présente une revue de certains résultats théoriques et observationnels concernant les divers effets de lentille gravitationnelle, complétée par des résultats nouveaux non encore publiés. Dans la partie théorique, nous considérons essentiellement l'approche relativiste employant les équations scalaires optiques. La forme de ces équations est rappelée : elles relient les diverses d

  11. Academic Training: Gravitational Waves Astronomy

    CERN Multimedia

    2006-01-01

    2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 16, 17, 18 October from 11:00 to 12:00 - Main Auditorium, bldg. 500 Gravitational Waves Astronomy M. LANDRY, LIGO Hanford Observatory, Richland, USA Gravitational wave astronomy is expected to become an observational field within the next decade. First direct detection of gravitational waves is possible with existing terrestrial-based detectors, and highly probable with proposed upgrades. In this three-part lecture series, we give an overview of the field, including material on gravitional wave sources, detection methods, some details of interferometric detectors, data analysis methods, and current results from observational data-taking runs of the LIGO and GEO projects. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www...

  12. Gravitational energy sources in Jupiter

    Science.gov (United States)

    Flasar, F. M.

    1973-01-01

    Gravitational sources of the intrinsic luminosity of Jupiter are examined in the context of current hydrogen-helium models. When no gravitational separation of matter occurs, the amount of heat which can be released over the remaining lifetime of the planet is necessarily limited by the size of its existing reservoir of thermal energy. This conclusion rests only on the assumption that its interior is relatively cold and degenerate. If gravitational unmixing occurs, the size of the thermal reservoir does not necessarily limit the heat output. If core formation occurs, for example, then the size of the core formed will be a limiting factor. The energy released with the formation of a helium core is computed for Jupiter. A core growth rate, averaged over several billion years, of 20 trillionths of Jupiter's mass per year is required if gravitational separation is to play a significant role in the thermal evolution.

  13. Highlights in gravitation and cosmology

    International Nuclear Information System (INIS)

    This book assesses research into gravitation and cosmology by examining the subject from various viewpoints: the classical and quantum pictures, along with the cosmological and astrophysical applications. There are 35 articles by experts of international standing. Each defines the state of the art and contains a concise summary of our present knowledge of a facet of gravitational physics. These edited papers are based on those first given at an international conference held in Goa, India at the end of 1987. The following broad areas are covered: classical relativity, quantum gravity, cosmology, black holes, compact objects, gravitational radiation and gravity experiments. In this volume there are also summaries of discussions on the following special topics: exact solutions of cosmological equations, mathematical aspects of general relativity, the early universe, and quantum gravity. For research workers in cosmology and gravitation this reference book provides a broad view of present achievements and current problems. (author)

  14. Implosion of quadrupole gravitational waves

    OpenAIRE

    Bonnor, W. B.; Piper, M. S.

    1996-01-01

    Einstein's vacuum equations are solved up to the second approximation for imploding quadrupole gravitational waves. The implosion generates a black hole singularity irrespective of the strength of the waves.

  15. Gravitational redshift in Kerr field

    International Nuclear Information System (INIS)

    Generally gravitational redshift has been calculated without consideration of rotation of a body. Neglecting the rotation, the geometry of space time can be described by using the well-known spherically symmetric Schwarzschild geometry. Rotation has great effect on general relativity, which gives new challenges on gravitational redshift. When rotation is taken into consideration spherical symmetry lost and off diagonal terms appears in the metric and the geometry of space time can be described by using the Kerr solution, which is the exact solution of the Einstein's field equations known at present. In this paper we will derive the expression for gravitational redshift for rotating source in Kerr field, and also apply the derived expression to calculate the gravitational redshift in case of Sun under Newtonian approximation of angular momentum

  16. Gravitational perturbation of traversable wormhole

    OpenAIRE

    Kim, Sung-Won

    2004-01-01

    In this paper, we study the perturbation problem of the scalar, electromagnetic, and gravitational waves under the traversable Lorentzian wormhole geometry. The unified form of the potential for the Schr\\"odinger type one-dimensional wave equation is found.

  17. Anomalous magnetic moment with heavy virtual leptons

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, Alexander [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Liu, Tao; Steinhauser, Matthias [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2013-11-15

    We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.

  18. The charmonium dissociation in an "anomalous wind"

    CERN Document Server

    Sadofyev, Andrey V

    2016-01-01

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries ``anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the ``anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the ``anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and {\\it qualitative} difference between anomalous effects on the charmonium color screening length which are {\\it model-dependent} and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by chiral anomaly in heavy ion collisions.

  19. The charmonium dissociation in an "anomalous wind"

    Science.gov (United States)

    Sadofyev, Andrey V.; Yin, Yi

    2016-01-01

    We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and qualitative difference between anomalous effects on the charmonium color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.

  20. Could the Pioneer anomaly have a gravitational origin?

    International Nuclear Information System (INIS)

    If the Pioneer anomaly has a gravitational origin, it would, according to the equivalence principle, distort the motions of the planets in the Solar System. Since no anomalous motion of the planets has been detected, it is generally believed that the Pioneer anomaly can not originate from a gravitational source in the Solar System. However, this conclusion becomes less obvious when considering models that either imply modifications to gravity over long distances or gravitational sources localized to the outer Solar System, given the uncertainty in the orbital parameters of the outer planets. Following the general assumption that the Pioneer spacecraft move geodesically in a spherically symmetric space-time metric, we derive the metric disturbance that is needed in order to account for the Pioneer anomaly. We then analyze the residual effects on the astronomical observables of the three outer planets that would arise from this metric disturbance, given an arbitrary metric theory of gravity. Providing a method for comparing the computed residuals with actual residuals, our results imply that the presence of a perturbation to the gravitational field necessary to induce the Pioneer anomaly is in conflict with available data for the planets Uranus and Pluto, but not for Neptune. We therefore conclude that the motion of the Pioneer spacecraft must be nongeodesic. Since our results are model-independent within the class of metric theories of gravity, they can be applied to rule out any model of the Pioneer anomaly that implies that the Pioneer spacecraft move geodesically in a perturbed space-time metric, regardless of the origin of this metric disturbance

  1. Dark Energy, Gravitation and Electromagnetism

    OpenAIRE

    B. G. Sidharth

    2004-01-01

    In the context of the fact that the existence of dark energy causing the accelerated expansion of the universe has been confirmed by the WMAP and the Sloan Digital Sky Survey, we re-examine gravitation itself, starting with the formulation of Sakharov and show that it is possible to obtain gravitation in terms of the electromagnetic charge of elementary particles, once the ZPF and its effects at the Compton scale are taken into account.

  2. Gravitational Waves, Sources and Detectors

    OpenAIRE

    Schutz, B.; Ricci, F

    2001-01-01

    Gravitational waves and their detection are becoming more and more important both for the theoretical physicist and the astrophysicist. In fact, technological developments have enabled the construction such sensitive detectors (bars and interferometers) that the detection of gravitational radiation could become a reality during the next few years. In these lectures we give a brief overview of this interesting and challenging field of modern physics. The topics to be covered are divided into ...

  3. Gravitational-wave sensitivity curves

    International Nuclear Information System (INIS)

    There are several common conventions in use by the gravitational-wave community to describe the amplitude of sources and the sensitivity of detectors. These are frequently confused. We outline the merits of and differences between the various quantities used for parameterizing noise curves and characterizing gravitational-wave amplitudes. We conclude by producing plots that consistently compare different detectors. Similar figures can be generated on-line for general use at http://rhcole.com/apps/GWplotter. (paper)

  4. Atom gravimeters and gravitational redshift

    CERN Document Server

    Wolf, Peter; Borde, Christian J; Reynaud, Serge; Salomon, Christophe; Cohen-Tannoudji, Claude; 10.1038/nature09340

    2010-01-01

    In a recent paper, H. Mueller, A. Peters and S. Chu [A precision measurement of the gravitational redshift by the interference of matter waves, Nature 463, 926-929 (2010)] argued that atom interferometry experiments published a decade ago did in fact measure the gravitational redshift on the quantum clock operating at the very high Compton frequency associated with the rest mass of the Caesium atom. In the present Communication we show that this interpretation is incorrect.

  5. Gravitational decoherence of atomic interferometers

    OpenAIRE

    Lamine, Brahim; Jaekel, Marc-Thierry; Reynaud, Serge

    2002-01-01

    We study the decoherence of atomic interferometers due to the scattering of stochastic gravitational waves. We evaluate the `direct' gravitational effect registered by the phase of the matter waves as well as the `indirect' effect registered by the light waves used as beam-splitters and mirrors for the matter waves. Considering as an example the space project HYPER, we show that both effects are negligible for the presently studied interferometers.

  6. Gravitational Law in Extra Dimensions

    OpenAIRE

    Bühlmann, Michael

    2013-01-01

    Some recent theories which try to amend shortcomings of current models in physics suggest the existence of additional dimensions. Such extra dimensions would modify the inverse square law of gravity. A short overview over gravitational theory is presented and some of the extensions to general relativity and models which use extra dimensions, so-called Kaluza–Klein theories are discussed. A derivation of the correction to Newton’s gravitational law due to extra dimensions is performed and yiel...

  7. Observation of photonic anomalous Floquet Topological Insulators

    CERN Document Server

    Maczewsky, Lukas J; Nolte, Stefan; Szameit, Alexander

    2016-01-01

    Commonly, a two-dimensional topological insulator is characterized by non-zero Chern numbers associated with its band structure. In our work, we present the experimental demonstration of an anomalous topological insulator, for which the Chern numbers are always zero, and the winding number is the appropriate quantity describing the topological character of the system. We probe the robustness of the chiral edge states in such anomalous topological insulators and analyze the phase transition between topological and trivial phase.

  8. Gauge Theories of Gravitation

    CERN Document Server

    Blagojević, Milutin

    2012-01-01

    During the last five decades, gravity, as one of the fundamental forces of nature, has been formulated as a gauge field theory of the Weyl-Cartan-Yang-Mills type. The resulting theory, the Poincar\\'e gauge theory of gravity, encompasses Einstein's gravitational theory as well as the teleparallel theory of gravity as subcases. In general, the spacetime structure is enriched by Cartan's torsion and the new theory can accommodate fermionic matter and its spin in a perfectly natural way. The present reprint volume contains articles from the most prominent proponents of the theory and is supplemented by detailed commentaries of the editors. This guided tour starts from special relativity and leads, in its first part, to general relativity and its gauge type extensions a la Weyl and Cartan. Subsequent stopping points are the theories of Yang-Mills and Utiyama and, as a particular vantage point, the theory of Sciama and Kibble. Later, the Poincar\\'e gauge theory and its generalizations are explored and specific topi...

  9. Noiseless Gravitational Lensing Simulations

    CERN Document Server

    Angulo, Raul E; Hilbert, Stefan; Abel, Tom

    2013-01-01

    The microphysical properties of the DM particle can, in principle, be constrained by the properties and abundance of substructures in DM halos, as measured through strong gravitational lensing. Unfortunately, there is a lack of accurate theoretical predictions for the lensing signal of substructures, mainly because of the discreteness noise inherent to N-body simulations. Here we present Recursive-TCM, a method that is able to provide lensing predictions with an arbitrarily low discreteness noise, without any free parameters or smoothing scale. This solution is based on a novel way of interpreting the results of N-body simulations, where particles simply trace the evolution and distortion of Lagrangian phase-space volume elements. We discuss the advantages of this method over the widely used cloud-in-cells and adaptive-kernel smoothing density estimators. Applying the new method to a cluster-sized DM halo simulated in warm and cold DM scenarios, we show how the expected differences in their substructure popul...

  10. Gravitational Wave in Lorentz Violating Gravity

    International Nuclear Information System (INIS)

    By making use of the weak gravitational field approximation, we obtain a linearized solution of the gravitational vacuum field equation in an anisotropic spacetime. The plane-wave solution and dispersion relation of gravitational wave is presented explicitly. There is possibility that the speed of gravitational wave is larger than the speed of light and the casuality still holds. We show that the energy-momentum of gravitational wave in the ansiotropic spacetime is still well defined and conserved. (general)

  11. Gravitational Waves: new observatories for new astronomy

    OpenAIRE

    Rubbo, Louis J.; Larson, Shane L.; Larson, Michelle B.; Zaleski, Kristina D.

    2005-01-01

    This article reviews the current status of gravitational wave astronomy and explains why astronomers are excited about the new generation of gravitational wave detectors. As part of the review we compare and contrast gravitational radiation to the more familiar electromagnetic radiation. We discuss the current indirect experimental evidence for gravitational waves and how current and future gravitational wave detectors will operate as our newest telescopes are pointed at the skies.

  12. Gravitational energy of a Schwarzschild black hole

    CERN Document Server

    Shimizu, Katsutaro

    2016-01-01

    In a previous paper, we proposed a new gravitational energy momentum tensor. Here we use this tensor to evaluate the gravitational energies both inside and outside the horizon of a Schwarzschild black hole. Our results show that all of the gravitational energy exists outside the horizon, and that there is no gravitational energy inside the horizon. We comment on a relation with our gravitational energy momentum tensor and another one which is proposed in a teleparallel gravity.

  13. Strong gravitational lensing of gravitational waves in Einstein Telescope

    International Nuclear Information System (INIS)

    Gravitational wave experiments have entered a new stage which gets us closer to the opening a new observational window on the Universe. In particular, the Einstein Telescope (ET) is designed to have a fantastic sensitivity that will provide with tens or hundreds of thousand NS-NS inspiral events per year up to the redshift z = 2. Some of such events should be gravitationally lensed by intervening galaxies. We explore the prospects of observing gravitationally lensed inspiral NS-NS events in the Einstein telescope. Being conservative we consider the lens population of elliptical galaxies. It turns out that depending on the local insipral rate ET should detect from one per decade detection in the pessimistic case to a tens of detections per year for the most optimistic case. The detection of gravitationally lensed source in gravitational wave detectors would be an invaluable source of information concerning cosmography, complementary to standard ones (like supernovae or BAO) independent of the local cosmic distance ladder calibrations

  14. On gravitational-electromagnetic resonance

    CERN Document Server

    Mensky, Michael B

    2007-01-01

    This is an English translation of the paper M.B.Mensky, in: K.P.Stanyukovich (ed.), "Problems of Theory of Gravity and Elementary Particles", issue 6, Moscow, Atomizdat, 1975, p.181-190 (in Russian). This paper elaborates further the idea (formulated in 1971 by Braginsky and Mensky) of detecting high-frequency gravitational waves by observing resonance action of a gravitational wave on the electromagnetic wave in a closed resonator (waveguide). The phenomenon underlying such a detector was called gravitational-electromagnetic resonance (GER). In the present paper both closed (for example circular) resonator or waveguide and long (for example in the shape of a spiral) waveguide are considered as possible gravitational-wave detectors. High-frequency gravitational-wave detectors are now again actual (see A.M.Cruise and R.M.J.Ingley, Class. Quant. Grav. 22, S479, 2005), but the current literature on this topic does not cover all the issues discussed in the present paper.

  15. Azimuthally symmetric theory of gravitation - II. On the perihelion precession of solar planetary orbits

    Science.gov (United States)

    Nyambuya, G. G.

    2015-08-01

    This paper presents an improved version of the azimuthally symmetric theory of gravitation (ASTG) model, which was presented for the first time in the present journal in 2010. I propose a solution to the standing problem of the λ-parameters and, in order to do this, I put the ASTG model on a clear pedestal for falsification. As in the first paper, the perihelion precessional data of solar planetary orbits is used to set the theory into motion. It is seen that the ASGT model is able to explain the anomalous perihelion precession that is explained by the general theory of relativity (GTR) as being a result of space-time curvature. The ASTG model explains that the anomalous perihelion precession is not a result of the curvature of space-time, as is the case with the GTR, but a result of the spin of the gravitating mass about which these test bodies orbit. In this way, the ASTG model provides a plausible alternative way to interpret the observed anomalous perihelion precession of solar planetary orbits.

  16. Analytical solutions for anomalous dispersion transport

    Science.gov (United States)

    O'Malley, D.; Vesselinov, V. V.

    2014-06-01

    Groundwater flow and transport often occur in a highly heterogeneous environment (potentially heterogeneous at multiple spatial scales) and is impacted by geochemical reactions, advection, diffusion, and other pore scale processes. All these factors can give rise to large-scale anomalous dispersive behavior that can make complex model representation and prediction of plume concentrations challenging due to difficulties unraveling all the complexities associated with the governing processes, flow medium, and their parameters. An alternative is to use upscaled stochastic models of anomalous dispersion, and this is the approach used here. Within a probabilistic framework, we derive a number of analytical solutions for several anomalous dispersion models. The anomalous dispersion models are allowed to be either non-Gaussian (α-stable Lévy), correlated, or nonstationary from the Lagrangian perspective. A global sensitivity analysis is performed to gain a greater understanding of the extent to which uncertainty in the parameters associated with the anomalous behavior can be narrowed by examining concentration measurements from a network of monitoring wells and to demonstrate the computational speed of the solutions. The developed analytical solutions are encoded and available for use in the open source computational framework MADS (http://mads.lanl.gov).

  17. Parametric probability distributions for anomalous change detection

    Energy Technology Data Exchange (ETDEWEB)

    Theiler, James P [Los Alamos National Laboratory; Foy, Bernard R [Los Alamos National Laboratory; Wohlberg, Brendt E [Los Alamos National Laboratory; Scovel, James C [Los Alamos National Laboratory

    2010-01-01

    The problem of anomalous change detection arises when two (or possibly more) images are taken of the same scene, but at different times. The aim is to discount the 'pervasive differences' that occur thoughout the imagery, due to the inevitably different conditions under which the images were taken (caused, for instance, by differences in illumination, atmospheric conditions, sensor calibration, or misregistration), and to focus instead on the 'anomalous changes' that actually take place in the scene. In general, anomalous change detection algorithms attempt to model these normal or pervasive differences, based on data taken directly from the imagery, and then identify as anomalous those pixels for which the model does not hold. For many algorithms, these models are expressed in terms of probability distributions, and there is a class of such algorithms that assume the distributions are Gaussian. By considering a broader class of distributions, however, a new class of anomalous change detection algorithms can be developed. We consider several parametric families of such distributions, derive the associated change detection algorithms, and compare the performance with standard algorithms that are based on Gaussian distributions. We find that it is often possible to significantly outperform these standard algorithms, even using relatively simple non-Gaussian models.

  18. Gravitational Fields of Conical Mass Distributions

    Directory of Open Access Journals (Sweden)

    Chifu Ebenezer Ndikilar

    2013-01-01

    Full Text Available The gravitational field of conical mass distributions is formulated using the general theory of relativity. The gravitational metric tensor is constructed and applied to the motion of test particles and photons in this gravitational field. The expression for gravitational time dilation is found to have the same form as that in spherical, oblate spheroidal, and prolate spheroidal gravitational fields and hence confirms an earlier assertion that this gravitational phenomena is invariant in form with various mass distributions. It is shown using the pure radial equation of motion that as a test particle moves closer to the conical mass distribution along the radial direction, its radial speed decreases.

  19. Spin gravitational resonance and graviton detection

    CERN Document Server

    Quach, James Q

    2016-01-01

    We develop a gravitational analogue of spin magnetic resonance, called spin gravitational resonance, whereby a gravitational wave interacts with a magnetic field to produce a spin transition. In particular, an external magnetic field separates the energy spin states of a spin-1/2 particle, and the presence of the gravitational wave produces a perturbation in the components of the magnetic field orthogonal to the gravitational wave propagation. In this framework we test Dyson's conjecture that individual gravitons cannot be detected. Although we find no fundamental laws preventing single gravitons being detected with spin gravitational resonance, we show that it cannot be used in practice, in support of Dyson's conjecture.

  20. Thought Experiments on Gravitational Forces

    CERN Document Server

    Lynden-Bell, Donald

    2013-01-01

    Large contributions to the near closure of the Universe and to the acceleration of its expansion are due to the gravitation of components of the stress-energy tensor other than its mass density. To familiarise astronomers with the gravitation of these components we conduct thought experiments on gravity, analogous to the real experiments that our forebears conducted on electricity. By analogy to the forces due to electric currents we investigate the gravitational forces due to the flows of momentum, angular momentum, and energy along a cylinder. Under tension the gravity of the cylinder decreases but the 'closure' of the 3-space around it increases. When the cylinder carries a torque the flow of angular momentum along it leads to a novel helical interpretation of Levi-Civita's external metric and a novel relativistic effect. Energy currents give gravomagnetic effects in which parallel currents repel and antiparallel currents attract, though such effects must be added to those of static gravity. The gravity of...

  1. The Optimal Gravitational Lens Telescope

    CERN Document Server

    Surdej, J; Coleman, P; Dominik, M; Habraken, S; Hanot, C; Coroller, H Le; Mawet, D; Quintana, H; Sadibekova, T; Sluse, D; 10.1088/0004-6256/139/5/1935

    2010-01-01

    Given an observed gravitational lens mirage produced by a foreground deflector (cf. galaxy, quasar, cluster,...), it is possible via numerical lens inversion to retrieve the real source image, taking full advantage of the magnifying power of the cosmic lens. This has been achieved in the past for several remarkable gravitational lens systems. Instead, we propose here to invert an observed multiply imaged source directly at the telescope using an ad-hoc optical instrument which is described in the present paper. Compared to the previous method, this should allow one to detect fainter source features as well as to use such an optimal gravitational lens telescope to explore even fainter objects located behind and near the lens. Laboratory and numerical experiments illustrate this new approach.

  2. Gravitational Origin of Dark Matter

    CERN Document Server

    Babichev, Eugeny; Raidal, Martti; Schmidt-May, Angnis; Urban, Federico; Veermäe, Hardi; von Strauss, Mikael

    2016-01-01

    Observational evidence for the existence of Dark Matter is limited to its gravitational effects. The extensive program for dedicated searches has yielded null results so far, challenging the most popular models. Here we propose that this is the case because the very existence of cold Dark Matter is a manifestation of gravity itself. The consistent bimetric theory of gravity, the only known ghost-free extension of General Relativity involving a massless and a massive spin-2 field, automatically contains a perfect Dark Matter candidate. We demonstrate that the massive spin-2 particle can be heavy, stable on cosmological scales, and that it interacts with matter only through a gravitational type of coupling. Remarkably, these features persist in the same region of parameter space where bimetric theory satisfies the current gravity tests. We show that the observed Dark Matter abundance can be generated via freeze-in and suggest possible particle physics and gravitational signatures of our bimetric Dark Matter mod...

  3. Highlights in gravitation and cosmology

    Science.gov (United States)

    Iyer, B. R.; Vishveshwara, C. V.; Narlikar, Jayant V.; Kembhavi, Ajit K.

    1988-01-01

    Theoretical and observational studies in gravitation and cosmology are discussed in reviews and reports presented at the international conference held in Goa, India on December 14-19, 1987. Sections are devoted to classical relativity, quantum gravity, black holes and compact objects, and gravitational-radiation and gravity experiments. Particular attention is given to exact solutions of the Einstein equations and their classification, the asymptotic structure of isolated systems, the physical properties and parameters of radiative space-times, canonical quantization of generally covariant systems, field theories of quantum gravity, observational and theoretical aspects of dark matter, gravitational lenses, cosmic strings and galaxy formation, black-hole thermodynamics, the general relativity of compact objects, the general-relativistic problem of motion and binary pulsars, and relativity and fifth-force experiments.

  4. Gravitational collapse and naked singularities

    Indian Academy of Sciences (India)

    Tomohiro Harada

    2004-10-01

    Gravitational collapse is one of the most striking phenomena in gravitational physics. The cosmic censorship conjecture has provided strong motivation for research in this field. In the absence of a general proof for censorship, many examples have been proposed, in which naked singularity is the outcome of gravitational collapse. Recent developments have revealed that there are examples of naked singularity formation in the collapse of physically reasonable matter fields, although the stability of these examples is still uncertain. We propose the concept of `effective naked singularities', which will be quite helpful because general relativity has limitation in its application at the high-energy end. The appearance of naked singularities is not detestable but can open a window for the new physics of strongly curved space-times.

  5. Gravitational Lensing - Einstein's Unfinished Symphony

    CERN Document Server

    Treu, Tommaso

    2014-01-01

    Gravitational lensing - the deflection of light rays by gravitating matter - has become a major tool in the armoury of the modern cosmologist. Proposed nearly a hundred years ago as a key feature of Einstein's theory of General Relativity, we trace the historical development since its verification at a solar eclipse in 1919. Einstein was apparently cautious about its practical utility and the subject lay dormant observationally for nearly 60 years. Nonetheless there has been rapid progress over the past twenty years. The technique allows astronomers to chart the distribution of dark matter on large and small scales thereby testing predictions of the standard cosmological model which assumes dark matter comprises a massive weakly-interacting particle. By measuring distances and tracing the growth of dark matter structure over cosmic time, gravitational lensing also holds great promise in determining whether the dark energy, postulated to explain the accelerated cosmic expansion, is a vacuum energy density or a...

  6. Gravitational Instabilities in Circumstellar Disks

    CERN Document Server

    Kratter, Kaitlin M

    2016-01-01

    [Abridged] Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability, and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability, supplemented with a survey of numerical simulations that aim to capture the non-linear evolution. We emphasize the role of thermodynamics and large scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analyt...

  7. Gravitational Baryogenesis after Anisotropic Inflation

    CERN Document Server

    Fukushima, Mitsuhiro; Maeda, Kei-ichi

    2016-01-01

    The gravitational baryogensis may not generate a sufficient baryon asymmetry in the standard thermal history of the Universe when we take into account the gravitino problem. Hence it has been suggested that anisotropy of the Universe can enhance the generation of the baryon asymmetry through the increase of the time change of the Ricci scalar curvature. We study the gravitational baryogenesis in the presence of anisotropy, which is produced at the end of an anisotropic inflation. Although we confirm that the generated baryon asymmetry is enhanced compared with the original isotropic cosmological model, taking into account the constraint on the anisotropy by the recent CMB observations, we find that it is still difficult to obtain the observed baryon asymmetry only through the gravitational baryogenesis without suffering from the gravitino problem.

  8. Gravitational waves from compact bodies

    CERN Document Server

    Thorne, K S

    1995-01-01

    A review is given of recent research on gravitational waves from compact bodies and its relevance to the LIGO/VIRGO international network of high-frequency (10 to 10,000 Hz) gravitational-wave detectors, and to the proposed LISA system of low-frequency (0.1 to 0.0001 Hz) detectors. The sources that are reviewed are ordinary binary star systems, binaries made from compact bodies (black holes and neutron stars), the final inspiral and coalescence of compact-body binaries, the inspiral of stars and small black holes into massive black holes, the stellar core collapse that triggers supernovae, and the spin of neutron stars. This paper is adapted from a longer review article entitled ``Gravitational Waves'' (GRP-411) that the author has written for the Proceedings of the Snowmass '94 Summer Study on Particle and Nuclear Astrophysics and Cosmology.

  9. Anomalous magnetohydrodynamics in the extreme relativistic domain

    CERN Document Server

    Giovannini, Massimo

    2016-01-01

    The evolution equations of anomalous magnetohydrodynamics are derived in the extreme relativistic regime and contrasted with the treatment of hydromagnetic nonlinearities pioneered by Lichnerowicz in the absence of anomalous currents. In particular we explore the situation where the conventional vector currents are complemented by the axial-vector currents arising either from the pseudo Nambu-Goldstone bosons of a spontaneously broken symmetry or because of finite fermionic density effects. After expanding the generally covariant equations in inverse powers of the conductivity, the relativistic analog of the magnetic diffusivity equation is derived in the presence of vortical and magnetic currents. While the anomalous contributions are generally suppressed by the diffusivity, they are shown to disappear in the perfectly conducting limit. When the flow is irrotational, boost-invariant and with vanishing four-acceleration the corresponding evolution equations are explicitly integrated so that the various physic...

  10. Anomalous fluorescence line intensity in megavoltage bremsstrahlung

    Science.gov (United States)

    Pereira, Nino; Litz, Marc; Merkel, George; Schumer, Joseph; Seely, John; Carroll, Jeff

    2009-11-01

    A Cauchois transmission crystal spectrometer intended for laser plasma diagnostics has measured an anomalous ratio between the fluorescence lines in megavoltage bremsstrahlung. When observed in reflection, Kα1 fluorescence is twice as strong as the Kβ line, as is usual. However, in forward-directed bremsstrahlung from a 2 MV end point linear accelerator with a tungsten converter, the Kα1 and Kβ fluorescence are approximately equal. The anomalous fluorescence line ratio, unity, reflects the large amount of fluorescence generated on the side of the converter where the electrons enter, and the differential attenuation of the fluorescence photons as they pass through the converter to opposite side. Understanding of fluorescence in megavoltage bremsstrahlung is relevant to the explanation of anomalous line ratios in spectra produced by high-energy electrons generated by intense femtosecond laser irradiation.

  11. Gravitational-wave mediated preheating

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Stephon [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Cormack, Sam, E-mail: samuel.c.cormack.gr@dartmouth.edu [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Marcianò, Antonino [Center for Field Theory and Particle Physics & Department of Physics, Fudan University, 200433 Shanghai (China); Yunes, Nicolás [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States)

    2015-04-09

    We propose a new preheating mechanism through the coupling of the gravitational field to both the inflaton and matter fields, without direct inflaton–matter couplings. The inflaton transfers power to the matter fields through interactions with gravitational waves, which are exponentially enhanced due to an inflation–graviton coupling. One such coupling is the product of the inflaton to the Pontryagin density, as in dynamical Chern–Simons gravity. The energy scales involved are constrained by requiring that preheating happens fast during matter domination.

  12. Gravitational-wave mediated preheating

    Directory of Open Access Journals (Sweden)

    Stephon Alexander

    2015-04-01

    Full Text Available We propose a new preheating mechanism through the coupling of the gravitational field to both the inflaton and matter fields, without direct inflaton–matter couplings. The inflaton transfers power to the matter fields through interactions with gravitational waves, which are exponentially enhanced due to an inflation–graviton coupling. One such coupling is the product of the inflaton to the Pontryagin density, as in dynamical Chern–Simons gravity. The energy scales involved are constrained by requiring that preheating happens fast during matter domination.

  13. Gravitational-wave mediated preheating

    International Nuclear Information System (INIS)

    We propose a new preheating mechanism through the coupling of the gravitational field to both the inflaton and matter fields, without direct inflaton–matter couplings. The inflaton transfers power to the matter fields through interactions with gravitational waves, which are exponentially enhanced due to an inflation–graviton coupling. One such coupling is the product of the inflaton to the Pontryagin density, as in dynamical Chern–Simons gravity. The energy scales involved are constrained by requiring that preheating happens fast during matter domination

  14. General relativity and gravitational waves

    CERN Document Server

    Weber, J

    2004-01-01

    An internationally famous physicist and electrical engineer, the author of this text was a pioneer in the investigation of gravitational waves. Joseph Weber's General Relativity and Gravitational Waves offers a classic treatment of the subject. Appropriate for upper-level undergraduates and graduate students, this text remains ever relevant. Brief but thorough in its introduction to the foundations of general relativity, it also examines the elements of Riemannian geometry and tensor calculus applicable to this field.Approximately a quarter of the contents explores theoretical and experimenta

  15. Development of anomalous detection using movie prediction

    International Nuclear Information System (INIS)

    In this research, the new method to predict the near-future of the movie images captured by video camera based on the combination of the Principle Component Analysis (PCA) and the Singular Spectral Analysis (SSA). In the normal condition of machines, the real-time captured movie is supposed to correspond to the predicted one. If the error between the both becomes significantly large, it may suggest some anomalous motion of the machines. So the movie prediction method has a possibility of the sensitive anomalous detection system. (author)

  16. Anomalous cross field flux in CHS

    International Nuclear Information System (INIS)

    Anomalous quasi-linear fluxes induced by the curvature drift resonance and transit resonance are evaluated in a rotating helical plasma. The radial electric field makes the Doppler shift, but does not contribute to the anomalous fluxes. The curvature drift resonance induces the new curvature term in the quasi-linear fluxes. The effect of helical magnetic field is through this curvature of magnetic field lines, and contributes to the inward transport. The ion heat diffusivity due to the curvature drift resonance is obtained in the form modified gyro-Bohm coefficient, and is compared with experimentally observed one in CHS Heliotron. (author)

  17. Anomalous Resistance in Critical Ionization Velocity Phenomena

    CERN Document Server

    Badin, V I

    2001-01-01

    To describe the generation of the electric field by a discontinuity of the Hall current, an equation of the third order is obtained using the electric charge conservation and Ohm laws. The solutions of this equation are used to model the electric impulses detected in experiments aimed to verify Alfven's hypothesis on the critical ionization velocity at collisions of neutral gas with magnetized plasma. A quantitative agreement with experiment is attained and the main features of measured signals are modeled under an assumption on the strong anomalous resistance behind the discontinuity. Apparently, the anomalous resistance occurs due to trapping the current carriers by a small-scaled modulation of the electric field.

  18. Anomalous Hall effect for semiclassical chiral fermions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pengming, E-mail: zhpm@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Horváthy, P.A., E-mail: horvathy@lmpt.univ-tours.fr [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Laboratoire de Mathématiques et de Physique Théorique, Université de Tours (France)

    2015-03-06

    Semiclassical chiral fermions manifest the anomalous spin-Hall effect: when put into a pure electric field they suffer a side jump, analogous to what happens to their massive counterparts in non-commutative mechanics. The transverse shift is consistent with the conservation of the angular momentum. In a pure magnetic field, instead, spiraling motion is found. Motion in Hall-type perpendicular electric and magnetic fields is also studied. - Highlights: • Chiral fermions exhibit an anomalous spin-Hall effect. • Transverse shift appears in a pure electric field. • In a pure magnetic field spiraling motion is found.

  19. Anomalous transport equations in toroidal plasmas

    International Nuclear Information System (INIS)

    Reduced transport equations for a toroidal plasma with fluctuations are derived. These equations include the effects of both anomalous and standard neoclassical transport, and allow clarification of the structure of convective fluxes caused by electrostatic and magnetic fluctuations. Special attention is paid to the combined effects of fluctuations and toroidicity on the transport. The formulation retains the effects of a magnetic field inhomogeneity on the anomalous transport. It is shown that phase space diffusion caused by the gradient in the equilibrium magnetic field appears as a pinch flux in the real space

  20. The Theory of Vortical Gravitational Fields

    Directory of Open Access Journals (Sweden)

    Rabounski D.

    2007-04-01

    Full Text Available This paper treats of vortical gravitational fields, a tensor of which is the rotor of the general covariant gravitational inertial force. The field equations for a vortical gravitational field (the Lorentz condition, the Maxwell-like equations, and the continuity equation are deduced in an analogous fashion to electrodynamics. From the equations it is concluded that the main kind of vortical gravitational fields is “electric”, determined by the non-stationarity of the acting gravitational inertial force. Such a field is a medium for traveling waves of the force (they are different to the weak deformation waves of the space metric considered in the theory of gravitational waves. Standing waves of the gravitational inertial force and their medium, a vortical gravitational field of the “magnetic” kind, are exotic, since a non-stationary rotation of a space body (the source of such a field is a very rare phenomenon in the Universe.

  1. Gravitational waves carrying orbital angular momentum

    Science.gov (United States)

    Bialynicki-Birula, Iwo; Bialynicka-Birula, Zofia

    2016-02-01

    Spinorial formalism is used to map every electromagnetic wave into the gravitational wave (within the linearized gravity). In this way we can obtain the gravitational counterparts of Bessel, Laguerre-Gauss, and other light beams carrying orbital angular momentum.

  2. Concerning the vacuum velocity of gravitational waves

    OpenAIRE

    Pleitez, Vicente

    1995-01-01

    It is pointed out that if gravitational interactions among ordinary bodies propagate in extra space-time dimensions the velocity of gravitational waves in vacuum could be different from the speed of light $c$.

  3. Merging Black Holes and Gravitational Waves

    Science.gov (United States)

    Centrella, Joan

    2009-01-01

    This talk will focus on simulations of binary black hole mergers and the gravitational wave signals they produce. Applications to gravitational wave detection with LISA, and electronagnetic counterparts, will be highlighted.

  4. Gravitating BPS dyons witout a dilaton

    CERN Document Server

    Lee, C; Lee, Choonkyu; Park, Q Han

    1996-01-01

    We describe curved-space BPS dyon solutions, the ADM mass of which saturates the gravitational version of the Bogomol'nyi bound. This generalizes self-gravitating BPS monopole solutions of Gibbons et al. when there is no dilaton.

  5. Einstein's Energy-Free Gravitational Field

    OpenAIRE

    Dalton, Kenneth

    1995-01-01

    We show that Einstein's gravitational field has zero energy, momentum, and stress. This conclusion follows directly from the gravitational field equations, in conjunction with the differential law of energy-momentum conservation $ T^{\\mu\

  6. Gravitational waves carrying orbital angular momentum

    CERN Document Server

    Bialynicki-Birula, Iwo

    2015-01-01

    Spinorial formalism is used to map every electromagnetic wave into the gravitational wave (within the linearized gravity). In this way we can obtain the gravitational counterparts of Bessel, Laguerre-Gauss, and other light beams carrying orbital angular momentum.

  7. [Anomalous systemic arterial supply to left basal lung with anomalous return of V6].

    Science.gov (United States)

    Yabuki, Hiroshi; Shibuya, Jotaro; Handa, Masashi; Yamada, Takehiro

    2014-11-01

    The patient was 52-year-old woman. Her chief compliant was bloody sputum. The computed tomography revealed an anomalous artery from descending aorta running into left lung basal segment and anomalous left V6 return to superior pulmonary vein. The bronchoscopic examination showed normal bronchial branches. Under the diagnosis of anomalous systemic arterial supply to left basal lung without sequestration, left lower lobectomy was performed. Microscopically, the pulmonary artery showed intimal thickening and alveolar collapse with interstitial fibrosis were seen. The postoperative course was uneventful and she discharged at 6th postoperative day. PMID:25391467

  8. Gravitational Waves in Effective Quantum Gravity

    OpenAIRE

    Calmet, Xavier; Kuntz, Iberê; Mohapatra, Sonali

    2016-01-01

    In this short paper we investigate quantum gravitational effects on Einstein's equations using effective field theory techniques. We consider the leading order quantum gravitational correction to the wave equation. Besides the usual massless mode, we find a pair of modes with complex masses. These massive particles have a width and could thus lead to a damping of gravitational waves if excited in violent astrophysical processes producing gravitational waves such as e.g. black hole mergers. We...

  9. GRAVITATIONAL WAVES AND SCHRODINGER QUANTUM THEORY

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2014-02-01

    Full Text Available In this paper, we consider gravitation theory in multidimensional space. The model of the metric satisfying the basic requirements of quantum theory is proposed. It is shown that gravitational waves are described by the Liouville equation. Conjecture about the Schrödinger wave function due to gravitational waves was proved. Solutions of the gravitational field equations similar to the de Broglie waves have been constructed.

  10. Fast Magnetosonic Waves Driven by Gravitational Waves

    OpenAIRE

    Papadopoulos, D.; Stergioulas, N.; Vlahos, L.; Kuijpers, J.

    2001-01-01

    The propagation of a gravitational wave (GW) through a magnetized plasma is considered. In particular, we study the excitation of fast magnetosonic waves (MSW) by a gravitational wave, using the linearized general-relativistic hydromagnetic equations. We derive the dispersion relation for the plasma, treating the gravitational wave as a perturbation in a Minkowski background space-time. We show that the presence of gravitational waves will drive magnetosonic waves in the plasma and discuss th...

  11. On the polarization of nonlinear gravitational waves

    OpenAIRE

    Poplawski, Nikodem J.

    2011-01-01

    We derive a relation between the two polarization modes of a plane, linear gravitational wave in the second-order approximation. Since these two polarizations are not independent, an initially monochromatic gravitational wave loses its periodic character due to the nonlinearity of the Einstein field equations. Accordingly, real gravitational waves may differ from solutions of the linearized field equations, which are being assumed in gravitational-wave detectors.

  12. Gravitational waves from smooth hybrid new infation

    OpenAIRE

    Kawasaki, Masahiro; Saikawa, Ken'ichi; Takeda, Naoyuki

    2012-01-01

    We calculate the production of the gravitational waves from a double inflation model with lattice simulations. Between the two inflationary stages, gravitational waves with a characteristic frequency are produced by fluctuations of the scalar fields enhanced through parametric resonance. The wavelength of the produced gravitational waves gets extra redshift during the second inflationary stage and it can be in the observable range for the direct gravitational wave detectors. It is found that ...

  13. The rotation of polarization by gravitational waves

    OpenAIRE

    Faraoni, Valerio

    2007-01-01

    There are conflicting statements in the literature about the gravitational Faraday rotation of the plane of polarization of polarized electromagnetic radiation travelling through a gravitational wave. This issue is reconsidered using a simple formalism describing the rotation of the plane of polarization in a gravitational field, in the geometric optics approximation. It is shown that, to first order in the gravitational wave amplitude, the rotation angle is a boundary effect which vanishes f...

  14. The Japanese space gravitational wave antenna - DECIGO

    OpenAIRE

    Kawamura, Seiji; Ando, Masaki; Nakamura,Takashi; Tsubono, Kimio; Tanaka, Takahiro; Funaki, Iklkoh; Seto, Naoki; Numata, Kenji; Sato, Shuichi; Ioka, Kunihito; Kanda, Nobuyuki; Takashima, Takeshi; Agatsuma, Kazuhiro; Akutsu, Tomotada; Akutsu, Tomomi

    2008-01-01

    DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. The goal of DECIGO is to detect gravitational waves from various kinds of sources mainly between 0.1 Hz and 10 Hz and thus to open a new window of observation for gravitational wave astronomy. DECIGO will consist of three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by a Fabry—Perot Michelson interferometer. We plan to lau...

  15. Astrometric and timing effects of gravitational waves

    OpenAIRE

    Schutz, B.

    2010-01-01

    Gravitational wave detection can be done by precision timing of millisecond pulsars, and (with less likelihood) by precision astrometry on distant objects whose light or radio waves pass through gravitational waves on their way to our observatories. Underlying both of these is the relatively simple theory of light propagation in spacetimes with gravitational waves, which is also the basis of interferometric gravitational wave detectors. I review this theory and apply it to the timing and astr...

  16. Vector-tensor interaction of gravitation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuan-zhong; Guo han-ying

    1982-11-01

    In the paper, by using the equation of motion a particle, we show that the antigravity exist in the vector-tensor model of gravitation. Thus the motion of a particle deviates from the geodesic equation. In Newtonian approximation and weak gravitational field, acceleration of a particle in a spherically symmetric and astatic gravitation field is zero. The result is obviously not in agreement with gravitational phenomena.

  17. Constructing black hole entropy from gravitational collapse

    OpenAIRE

    Acquaviva, Giovanni; Ellis, George F. R.; Goswami, Rituparno; Hamid, Aymen I. M.

    2016-01-01

    Based on a recent proposal for the gravitational entropy of free gravitational fields, we investigate the thermodynamic properties of black hole formation through gravitational collapse in the framework of the semitetrad 1+1+2 covariant formalism. In the simplest case of an Oppenheimer-Snyder-Datt collapse we prove that the change in gravitational entropy outside a collapsing body is related to the variation of the surface area of the body itself, even before the formation of horizons. As a r...

  18. How to test gravitation theories by means of gravitational-wave measurements

    Science.gov (United States)

    Thorne, K. S.

    1974-01-01

    Gravitational-wave experiments are a potentially powerful tool for testing gravitation theories. Most theories in the literature predict rather different polarization properties for gravitational waves than are predicted by general relativity; and many theories predict anomalies in the propagation speeds of gravitational waves.

  19. Academic Training: Gravitational Waves Astronomy

    CERN Multimedia

    2006-01-01

    2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 16, 17, 18 October from 11:00 to 12:00 - Main Auditorium, bldg. 500 Gravitational Waves Astronomy M. LANDRY, LIGO Hanford Observatory, Richland, USA Gravitational wave astronomy is expected to become an observational field within the next decade. First direct detection of gravitational waves is possible with existing terrestrial-based detectors, and highly probable with proposed upgrades. In this three-part lecture series, we give an overview of the field, including material on gravitional wave sources, detection methods, some details of interferometric detectors, data analysis methods, and current results from observational data-taking runs of the LIGO and GEO projects.ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www.cern...

  20. MACROSCOPIC ROTORS AND GRAVITATIONAL EFFECTS

    OpenAIRE

    Ritter, R.

    1981-01-01

    Astronomical bodies have, in the past, provided essentially the only macroscopic basis for studies of gravitation by means of rotations. Now new technology provides the possibility that laboratory rotors may be made more precise than astronomical ones. This article surveys the properties of some of both types of rotors and describes several laboratory experiments for tests of General Relativity.

  1. Gravitational Lensing: Einstein's unfinished symphony

    Science.gov (United States)

    Treu, Tommaso; Ellis, Richard S.

    2015-01-01

    Gravitational lensing - the deflection of light rays by gravitating matter - has become a major tool in the armoury of the modern cosmologist. Proposed nearly a hundred years ago as a key feature of Einstein's theory of general relativity, we trace the historical development since its verification at a solar eclipse in 1919. Einstein was apparently cautious about its practical utility and the subject lay dormant observationally for nearly 60 years. Nonetheless there has been rapid progress over the past twenty years. The technique allows astronomers to chart the distribution of dark matter on large and small scales thereby testing predictions of the standard cosmological model which assumes dark matter comprises a massive weakly-interacting particle. By measuring the distances and tracing the growth of dark matter structure over cosmic time, gravitational lensing also holds great promise in determining whether the dark energy, postulated to explain the accelerated cosmic expansion, is a vacuum energy density or a failure of general relativity on large scales. We illustrate the wide range of applications which harness the power of gravitational lensing, from searches for the earliest galaxies magnified by massive clusters to those for extrasolar planets which temporarily brighten a background star. We summarise the future prospects with dedicated ground and space-based facilities designed to exploit this remarkable physical phenomenon.

  2. Counteracting Gravitation In Dielectric Liquids

    Science.gov (United States)

    Israelsson, Ulf E.; Jackson, Henry W.; Strayer, Donald M.

    1993-01-01

    Force of gravity in variety of dielectric liquids counteracted by imposing suitably contoured electric fields. Technique makes possible to perform, on Earth, variety of experiments previously performed only in outer space and at great cost. Also used similarly in outer space to generate sort of artificial gravitation.

  3. Scaling Laws in Gravitational Collapse

    OpenAIRE

    Cai, Rong-Gen; Yang, Run-Qiu(State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190, China)

    2015-01-01

    This paper presents two interesting scaling laws, which relate some critical exponents in the critical behavior of spherically symmetric gravitational collapses. These scaling laws are independent of the details of gravity theory under consideration and share similar forms as those in thermodynamic and geometrical phase transitions in condensed matter system. The properties of the scaling laws are discussed and some numerical checks are given.

  4. Gravitating Disks Around Black Holes

    Czech Academy of Sciences Publication Activity Database

    Karas, Vladimír; Šubr, Ladislav

    Cambridge : Cambridge University Press, 2010 - (Peterson, B.), s. 332-332 ISBN 978-0-521-76502-2. - (IAU Symposium Proceedings Series. 267). [Symposium of the International Astronomical Union /267./. Rio de Janeiro (BR), 10.08.2009-14.08.2009] Institutional research plan: CEZ:AV0Z10030501 Keywords : accretion disks * gravitation * black hole physics Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  5. Gravitational Laser Back-Scattering

    OpenAIRE

    Novaes, S. F.; Spehler, D.

    1993-01-01

    A possible way of producing gravitons in the laboratory is investigated. We evaluate the cross section electron + photon $\\rightarrow$ electron + graviton in the framework of linearized gravitation, and analyse this reaction considering the photon coming either from a laser beam or from a Compton back-scattering process.

  6. Gravitational lensing in plasmic medium

    International Nuclear Information System (INIS)

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered

  7. Folding Gravitational-Wave Interferometers

    CERN Document Server

    Sanders, J R

    2016-01-01

    The sensitivity of kilometer-scale terrestrial gravitational wave interferometers is limited by mirror coating thermal noise. We explore the effect of folding the arm cavities of such interferometers. While simple folding alone does not reduce the mirror coating thermal noise, it makes the folding mirror the critical mirror, opening up a variety of design and upgrade options.

  8. Detecting gravitational waves from accreting neutron stars

    NARCIS (Netherlands)

    A.L. Watts; B. Krishnan

    2009-01-01

    The gravitational waves emitted by neutron stars carry unique information about their structure and composition. Direct detection of these gravitational waves, however, is a formidable technical challenge. In a recent study we quantified the hurdles facing searches for gravitational waves from the k

  9. Spinning particle in a gravitational field

    International Nuclear Information System (INIS)

    The equations of motion of a spinning particle in an external gravitational field are derived in a simple and general way. The extra force that makes the motion a nongeodesic one is a gravitational analogue of the Lorentz force. Arguments are given that fix the general form of the wave equation for particles of arbitrary spin in electromagnetic and gravitational fields

  10. Unification of Electromagnetic Interactions and Gravitational Interactions

    Institute of Scientific and Technical Information of China (English)

    WU Ning

    2002-01-01

    Unified theory of gravitational interactions and electromagnetic interactions is discussed in this paper.Based on gauge principle, electromagnetic interactions and gravitational interactions are formulated in the same mannerand are unified in a semi-direct product group of U(1) Abelian gauge group and gravitational gauge group.

  11. Unification of Electromagnetic Interactions and Gravitational Interactions

    Institute of Scientific and Technical Information of China (English)

    WUNing

    2002-01-01

    Unified theory of gravitational interactions and electromagnetic interactions is discussed in this paper.Based on gauge principle,electromagnetic interactions and gravitational interactions are formulated in the same manner and are unified in a semi-direct product group of U(1) Abelian gauge group and gravitational gauge group.

  12. Gravitational waves spectrum in squeezed vacuum state

    OpenAIRE

    Malsawmtluangi, N.; Suresh, P. K.

    2015-01-01

    Gravitational waves are placed in the squeezed vacuum state and obtained its spectrum for the expanding flat FLRW universe. The gravitational wave spectrum gets enhanced due to the squeezing effect and is likely to be detected with the Einstein Telescope. The spectral energy density of gravitational waves in the squeezed vacuum state does not exceed the nucleosynthesis upper bound.

  13. The damping of gravitational waves in dust

    CERN Document Server

    Svitek, Otakar

    2008-01-01

    We examine a simple model of interaction of gravitational waves with matter (primarily represented by dust). The aim is to investigate a possible damping effect on the intensity of gravitational wave when passing through media. This might be important for gravitational wave astronomy when the sources are obscured by dust or molecular clouds.

  14. Gravitational wave scintillation by a stellar cluster

    CERN Document Server

    Congedo, G; Longo, P; Nucita, A A; Vetrugno, D

    2006-01-01

    The diffraction effects on gravitational waves propagating through a stellar cluster are analyzed in the relevant approximation of Fresnel diffraction limit. We find that a gravitational wave scintillation effect - similar to the radio source scintillation effect - comes out naturally, implying that the gravitational wave intensity changes in a characteristic way as the observer moves.

  15. Gravitational Binding Energy in Charged Cylindrical Symmetry

    CERN Document Server

    Sharif, M

    2014-01-01

    We consider static cylindrically symmetric charged gravitating object with perfect fluid and investigate the gravitational binding energy. It is found that only the localized part of the mass function provides the gravitational binding energy, whereas the non-localized part generated by the electric coupling does not contribute for such energy.

  16. Unification of Electromagnetic Interactions and Gravitational Interactions

    OpenAIRE

    Wu, Ning

    2002-01-01

    Unified theory of gravitational interactions and electromagnetic interactions is discussed in this paper. Based on gauge principle, electromagnetic interactions and gravitational interactions are formulated in the same manner and are unified in a semi-direct product group of U(1) Abel gauge group and gravitational gauge group.

  17. Unification of Gravitation and Gauge Fields

    OpenAIRE

    Huang, Xin-Bing

    2004-01-01

    In this letter, I indicate that complex daor field should also have spinor suffixes. The gravitation and gauge fields are unified under the framework of daor field. I acquire the elegant coupling equation of gravitation and gauge fields, from which Einstein's gravitational equation can be deduced.

  18. Cosmological models and gravitational lenses

    International Nuclear Information System (INIS)

    Full text: The large amount of observational data collected since the early last century by Surveys as: CLASS, SNAP, SDSS and others, made the tests possible cosmological models. What stands out most is one that uses gravitational lensing, which serves as a complement to tests with SNe-Ia. Currently, the observations indicate that the universe is accelerated expansion. Moreover to that we have the cosmic structures we observe today as the need to add more material. A proposal usual to solve these problems is to propose the existence of two dark components. This name comes from the constituents emitted any radiation. However, despite both not emit radiation they must distort space-time somehow. Thus, when a beam of light from any source in this region spreads geometrically modified, will have its trajectory changed. Therefore, the phenomenon of gravitational lensing allows infer indirectly the amount of dark matter in the universe. Moreover, the study of gravitational lensing enables to obtain cosmological parameters as the Hubble constant and density parameter. Moreover, this effect can heaven be used to detect exoplanets, or also as a natural telescope. In this study aims to assess some cosmological models using gravitational lenses and the CLASS data in tests with fluids quartessence. Such fluids are useful for treating the matter and dark energy as a single fluid. Unlike the model LambdaCDM that treats separately, i.e. in this model the universe consists of baryons, radiation, dust, dark matter and dark energy. We will use the statistics of gravitational lensing to make a comparison between the generalized Chaplygin gas and the viscous fluid. In addition, an application of statistics to the CLASS lenses will be applied in models well accepted by the scientific community. (author)

  19. Anomalous scalings in differential models of turbulence

    CERN Document Server

    Thalabard, Simon; Galtier, Sebastien; Sergey, Medvedev

    2015-01-01

    Differential models for hydrodynamic, passive-scalar and wave turbulence given by nonlinear first- and second-order evolution equations for the energy spectrum in the $k$-space were analysed. Both types of models predict formation an anomalous transient power-law spectra. The second-order models were analysed in terms of self-similar solutions of the second kind, and a phenomenological formula for the anomalous spectrum exponent was constructed using numerics for a broad range of parameters covering all known physical examples. The first-order models were examined analytically, including finding an analytical prediction for the anomalous exponent of the transient spectrum and description of formation of the Kolmogorov-type spectrum as a reflection wave from the dissipative scale back into the inertial range. The latter behaviour was linked to pre-shock/shock singularities similar to the ones arising in the Burgers equation. Existence of the transient anomalous scaling and the reflection-wave scenario are argu...

  20. Anomalous Hall Effect for chiral fermions

    CERN Document Server

    Zhang, P -M

    2014-01-01

    Semiclassical chiral fermions manifest the anomalous spin-Hall effect: when put into a pure electric field, they suffer a side jump, analogous to what happens to their massive counterparts in non-commutative mechanics. The transverse shift is consistent with the conservation of the angular momentum. In a pure magnetic field a cork-screw-like, spiraling motion is found.

  1. Anomalous Hall conductivity: Local orbitals approach

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel

    2010-01-01

    Roč. 82, č. 4 (2010), 045115/1-045115/9. ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * Berry phase correction * orbital polarization momentum Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  2. Anomalous fermion number violation and numerical simulations

    International Nuclear Information System (INIS)

    After discussing the problem of lattice regularization of chiral gauge theories, a simple model for anomalous fermion number violation is formulated which can be numerically studied with present day technique. Exploratory results of numerical simulations of a two-dimensional U(1) Higgs model are presented. (orig.)

  3. STIS MAMA Recovery from Anomalous Shutdown

    Science.gov (United States)

    Wheeler, Thomas

    2013-10-01

    This proposal is designed to permit a safe and orderly recovery of the STIS FUV MAMA or NUV MAMA detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP high-voltage ramp-ups and diagnostics. Anomalous shutdowns can occur because of bright object violations which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. Event flags are used to prevent inadvertent MAMA usage.The recovery procedure consists of three separate tests {i.e. visits} to check the MAMA's health after an anomalous shutdown: 1} signal processing electronics check, 2} slow, intermediate voltage high voltage ramp-up, and 3} ramp-up to full operating voltage followed by a fold analysis test {See STIS ISR 98-02R}. Each must be successfully completed before proceeding onto the next. This proposal executes the same steps as Cycle 20 proposal 13150.

  4. Anomalous Hall effect in disordered multiband metals

    Czech Academy of Sciences Publication Activity Database

    Kovalev, A.A.; Sinova, Jairo; Tserkovnyak, Y.

    2010-01-01

    Roč. 105, č. 3 (2010), 036601/1-036601/4. ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.621, year: 2010

  5. Anomalous N=2 superconformal Ward identities

    International Nuclear Information System (INIS)

    The N=2 superconformal Ward identities and their anomalies are discussed in N=2 superspace (including N=2 harmonic superspace), at the level of the low-energy effective action (LEEA) in four-dimensional N=2 supersymmetric field theories. The (first) chiral N=2 supergravity compensator is related to the known N=2 anomalous Ward identity in the N=2 (abelian) vector mulitplet sector. As regards the hypermultiplet LEEA given by the N=2 non-linear sigma-model (NLSM), a new anomalous N=2 superconformal Ward identity is found, whose existence is related to the (second) analytic compensator in N=2 supergravity. The celebrated solution of Seiberg and Witten is known to obey the (first) anomalous Ward identity in the Coulomb branch. We find a few solutions to the new anomalous Ward identity, after making certain assumptions about unbroken internal symmetries. Amongst the N=2 NLSM target space metrics governing the hypermultiplet LEEA are the SU(2)-Yang-Mills-Higgs monopole moduli-space metrics that can be encoded in terms of the spectral curves (Riemann surfaces), similarly to the Seiberg-Witten-type solutions. After a dimensional reduction to three spacetime dimensions (3d), our results support the mirror symmetry between the Coulomb and Higgs branches in 3d, N=4 gauge theories

  6. Anomalous wetting of helium on cesium

    International Nuclear Information System (INIS)

    The authors report studies of the anomalous wetting of a cesium substrate by a liquid helium film by means of the technique of third sound. A hysteretic pre-wetting transition is observed as a function of the amount of helium in the experimental cell. 10 refs., 2 figs

  7. Total least squares for anomalous change detection

    Energy Technology Data Exchange (ETDEWEB)

    Theiler, James P [Los Alamos National Laboratory; Matsekh, Anna M [Los Alamos National Laboratory

    2010-01-01

    A family of difference-based anomalous change detection algorithms is derived from a total least squares (TLSQ) framework. This provides an alternative to the well-known chronochrome algorithm, which is derived from ordinary least squares. In both cases, the most anomalous changes are identified with the pixels that exhibit the largest residuals with respect to the regression of the two images against each other. The family of TLSQ-based anomalous change detectors is shown to be equivalent to the subspace RX formulation for straight anomaly detection, but applied to the stacked space. However, this family is not invariant to linear coordinate transforms. On the other hand, whitened TLSQ is coordinate invariant, and furthermore it is shown to be equivalent to the optimized covariance equalization algorithm. What whitened TLSQ offers, in addition to connecting with a common language the derivations of two of the most popular anomalous change detection algorithms - chronochrome and covariance equalization - is a generalization of these algorithms with the potential for better performance.

  8. Anomalous Cepheids in the Sculptor dwarf galaxy

    International Nuclear Information System (INIS)

    The Sculptor dwarf galaxy contains at least three Cepheids (V25, V26, and V119), each with a period near 1 day and B magnitudes about 1.4 mag brighter than those of the Sculptor RR Lyrae stars. Low-resolution spectra of these so-called anomalous Cepheids were obtained. Metal abundances of the Cepheids have been determined by the Delta-S method and are found to be: Fe/H = -1.9 + or - 0.2, -1.8 + or - 0.2, and -2.2 + or - 0.3 for V25, V26, and V119, respectively. These values are consistent with the metal abundances of Sculptor red giants estimated from the color of the giant branch. Pulsational masses have been estimated for V25 and V26, but there is a need for improved photometry of these stars to obtain accurate results. It cannot be unambiguously established whether the Sculptor anomalous Cepheids are evolved single stars, aged about 3 Gyr, or whether they are created by mass transfer in older binary systems. The occurrence of anomalous Cepheids in other systems is discussed. There is some evidence that most anomalous Cepheids in the Small Magellanic Cloud are evolved single stars. 89 references

  9. Anomalous transport phenomena in px+i py superconductors

    Science.gov (United States)

    Li, Songci; Andreev, A. V.; Spivak, B. Z.

    2015-09-01

    Spontaneous breaking of time-reversal symmetry in superconductors with the px+i py symmetry of the order parameter allows for a class of effects which are analogous to the anomalous Hall effect in ferromagnets. These effects exist below the critical temperature, T anomalous Hall thermal conductivity, the polar Kerr effect, the anomalous Hall effect, and the anomalous photo- and acousto-galvanic effects.

  10. Effect of the Earth's Time-Retarded Transverse Gravitational Field on Spacecraft Flybys

    OpenAIRE

    Hafele, J. C.

    2009-01-01

    In 2008 a group of NASA scientists reported an anomalous change in the speed of six spacecraft flybys of the Earth. The reported speed change for the NEAR spacecraft flyby is 13.46+-0.01 mm/s. It is known that general relativity theory reduces to classical time-retarded electromagnetic field theory in the linearized approximation. This report shows that time-retarded field theory applied to the Earth's transverse gravitational field gives rise to a small change in the speed of a spacecraft du...

  11. The Japanese space gravitational wave antenna - DECIGO

    Science.gov (United States)

    Kawamura, S.; Ando, M.; Nakamura, T.; Tsubono, K.; Tanaka, T.; Funaki, I.; Seto, N.; Numata, K.; Sato, S.; Ioka, K.; Kanda, N.; Takashima, T.; Agatsuma, K.; Akutsu, T.; Akutsu, T.; Aoyanagi, Koh-Suke; Arai, K.; Arase, Y.; Araya, A.; Asada, H.; Aso, Y.; Chiba, T.; Ebisuzaki, T.; Enoki, M.; Eriguchi, Y.; Fujimoto, M.-K.; Fujita, R.; Fukushima, M.; Futamase, T.; Ganzu, K.; Harada, T.; Hashimoto, T.; Hayama, K.; Hikida, W.; Himemoto, Y.; Hirabayashi, H.; Hiramatsu, T.; Hong, F.-L.; Horisawa, H.; Hosokawa, M.; Ichiki, K.; Ikegami, T.; Inoue, K. T.; Ishidoshiro, K.; Ishihara, H.; Ishikawa, T.; Ishizaki, H.; Ito, H.; Itoh, Y.; Kamagasako, S.; Kawashima, N.; Kawazoe, F.; Kirihara, H.; Kishimoto, N.; Kiuchi, K.; Kobayashi, S.; Kohri, K.; Koizumi, H.; Kojima, Y.; Kokeyama, K.; Kokuyama, W.; Kotake, K.; Kozai, Y.; Kudoh, H.; Kunimori, H.; Kuninaka, H.; Kuroda, K.; Maeda, K.-i.; Matsuhara, H.; Mino, Y.; Miyakawa, O.; Miyoki, S.; Morimoto, M. Y.; Morioka, T.; Morisawa, T.; Moriwaki, S.; Mukohyama, S.; Musha, M.; Nagano, S.; Naito, I.; Nakagawa, N.; Nakamura, K.; Nakano, H.; Nakao, K.; Nakasuka, S.; Nakayama, Y.; Nishida, E.; Nishiyama, K.; Nishizawa, A.; Niwa, Y.; Ohashi, M.; Ohishi, N.; Ohkawa, M.; Okutomi, A.; Onozato, K.; Oohara, K.; Sago, N.; Saijo, M.; Sakagami, M.; Sakai, S.-i.; Sakata, S.; Sasaki, M.; Sato, T.; Shibata, M.; Shinkai, H.; Somiya, K.; Sotani, H.; Sugiyama, N.; Suwa, Y.; Tagoshi, H.; Takahashi, K.; Takahashi, K.; Takahashi, T.; Takahashi, H.; Takahashi, R.; Takahashi, R.; Takamori, A.; Takano, T.; Taniguchi, K.; Taruya, A.; Tashiro, H.; Tokuda, M.; Tokunari, M.; Toyoshima, M.; Tsujikawa, S.; Tsunesada, Y.; Ueda, K.-i.; Utashima, M.; Yamakawa, H.; Yamamoto, K.; Yamazaki, T.; Yokoyama, J.; Yoo, C.-M.; Yoshida, S.; Yoshino, T.

    2008-07-01

    DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. The goal of DECIGO is to detect gravitational waves from various kinds of sources mainly between 0.1 Hz and 10 Hz and thus to open a new window of observation for gravitational wave astronomy. DECIGO will consist of three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by a Fabry—Perot Michelson interferometer. We plan to launch DECIGO pathfinder first to demonstrate the technologies required to realize DECIGO and, if possible, to detect gravitational waves from our galaxy or nearby galaxies.

  12. Gravitational Gauge Interactions of Dirac Field

    Institute of Scientific and Technical Information of China (English)

    WU Ning

    2004-01-01

    Gravitational interactions of Dirac field are studied in this paper. Based on gauge principle, quantum gauge theory of gravity, which is perturbatively renormalizable, is formulated in the Minkowski space-time. In quantum gauge theory of gravity, gravity is treated as a kind of fundamental interactions, which is transmitted by gravitational gauge tield, and Dirac field couples to gravitational field through gravitational gauge covariant derivative. Based on this theory, we can easily explain gravitational phase effect, which has already been detected by COW experiment.

  13. Gravitational Waves in Effective Quantum Gravity

    CERN Document Server

    Calmet, Xavier; Mohapatra, Sonali

    2016-01-01

    In this short paper we investigate quantum gravitational effects on Einstein's equations using effective field theory techniques. We consider the leading order quantum gravitational correction to the wave equation. Besides the usual massless mode, we find a pair of modes with complex masses. These massive particles have a width and could thus lead to a damping of gravitational waves if excited in violent astrophysical processes producing gravitational waves such as e.g. black hole mergers. We discuss the consequences for gravitational wave events such as GW 150914 recently observed by the Advanced LIGO collaboration.

  14. Gravitational Waves from Neutron Stars: A Review

    CERN Document Server

    Lasky, Paul D

    2015-01-01

    Neutron stars are excellent emitters of gravitational waves. Squeezing matter beyond nuclear densities invites exotic physical processes, many of which violently transfer large amounts of mass at relativistic velocities, disrupting spacetime and generating copious quantities of gravitational radiation. I review mechanisms for generating gravitational waves with neutron stars. This includes gravitational waves from radio and millisecond pulsars, magnetars, accreting systems and newly born neutron stars, with mechanisms including magnetic and thermoelastic deformations, various stellar oscillation modes and core superfluid turbulence. I also focus on what physics can be learnt from a gravitational wave detection, and where additional research is required to fully understand the dominant physical processes at play.

  15. Gravitational Waves in Effective Quantum Gravity

    Science.gov (United States)

    Calmet, Xavier; Kuntz, Iberê; Mohapatra, Sonali

    2016-08-01

    In this short paper we investigate quantum gravitational effects on Einstein's equations using Effective Field Theory techniques. We consider the leading order quantum gravitational correction to the wave equation. Besides the usual massless mode, we find a pair of modes with complex masses. These massive particles have a width and could thus lead to a damping of gravitational waves if excited in violent astrophysical processes producing gravitational waves such as e.g. black hole mergers. We discuss the consequences for gravitational wave events such as GW 150914 recently observed by the Advanced LIGO collaboration.

  16. Gravitational collapse of gravitational waves in 3D numerical relativity.

    OpenAIRE

    Alcubierre, M.; Allen, G; Brügmann, B.; Lanfermann, G.; Seidel, E; Suen, W; Tobias, M

    2000-01-01

    We demonstrate that evolutions of three-dimensional, strongly non-linear gravitational waves can be followed in numerical relativity, hence allowing many interesting studies of both fundamental and observational consequences. We study the evolution of time-symmetric, axisymmetric and non-axisymmetric Brill waves, including waves so strong that they collapse to form black holes under their own self-gravity. An estimate for the critical amplitude for black hole formation in a particular interpo...

  17. Gravitational wave radiometry: Mapping a stochastic gravitational wave background

    International Nuclear Information System (INIS)

    The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either cosmological or astrophysical, bears a strong semblance to the analysis of the cosmic microwave background (CMB) anisotropy and polarization, which too is a stochastic field, statistically described in terms of its correlation properties. An astrophysical gravitational wave background (AGWB) will likely arise from an incoherent superposition of unmodelled and/or unresolved sources and cosmological gravitational wave backgrounds (CGWB) are also predicted in certain scenarios. The basic statistic we use is the cross correlation between the data from a pair of detectors. In order to ''point'' the pair of detectors at different locations one must suitably delay the signal by the amount it takes for the gravitational waves (GW) to travel to both detectors corresponding to a source direction. Then the raw (observed) sky map of the SGWB is the signal convolved with a beam response function that varies with location in the sky. We first present a thorough analytic understanding of the structure of the beam response function using an analytic approach employing the stationary phase approximation. The true sky map is obtained by numerically deconvolving the beam function in the integral (convolution) equation. We adopt the maximum likelihood framework to estimate the true sky map using the conjugate gradient method that has been successfully used in the broadly similar, well-studied CMB map-making problem. We numerically implement and demonstrate the method on signal generated by simulated (unpolarized) SGWB for the GW radiometer consisting of the LIGO pair of detectors at Hanford and Livingston. We include 'realistic' additive Gaussian noise in each data stream based on the LIGO-I noise power spectral density. The extension of the method to multiple baselines and polarized GWB is outlined. In the near future the network of GW detectors, including the Advanced LIGO and Virgo

  18. Anomalous Fluctuations in Observations of Q0957+561 A,B: Smoking Gun of a Cosmic String?

    CERN Document Server

    Schild, R; Hnatyk, B; Zhdanov, V I

    2004-01-01

    We report the detection of anomalous brightness fluctuations in the multiple image Q0957+561 A,B gravitational lens system, and consider whether such anomalies have a plausible interpretation within the framework of cosmic string theory. We study a simple model of gravitational lensing by an asymmetrical rotating string. An explicit form of the lens equation is obtained and approximate relations for magnification are derived. We show that such a model with typical parameters of the GUT string can quantitatively reproduce the observed pattern of brightness fluctuations. On the other hand, explanation involving a binary star system as an alternative cause requires an unacceptably large massive object at a small distance. We also discuss possible observational manifestations of cosmic strings within our lens model.

  19. Spherical gravitational curvature boundary-value problem

    Science.gov (United States)

    Šprlák, Michal; Novák, Pavel

    2016-08-01

    Values of scalar, vector and second-order tensor parameters of the Earth's gravitational field have been collected by various sensors in geodesy and geophysics. Such observables have been widely exploited in different parametrization methods for the gravitational field modelling. Moreover, theoretical aspects of these quantities have extensively been studied and well understood. On the other hand, new sensors for observing gravitational curvatures, i.e., components of the third-order gravitational tensor, are currently under development. As the gravitational curvatures represent new types of observables, their exploitation for modelling of the Earth's gravitational field is a subject of this study. Firstly, the gravitational curvature tensor is decomposed into six parts which are expanded in terms of third-order tensor spherical harmonics. Secondly, gravitational curvature boundary-value problems defined for four combinations of the gravitational curvatures are formulated and solved in spectral and spatial domains. Thirdly, properties of the corresponding sub-integral kernels are investigated. The presented mathematical formulations reveal some important properties of the gravitational curvatures and extend the so-called Meissl scheme, i.e., an important theoretical framework that relates various parameters of the Earth's gravitational field.

  20. THE FAINTEST RADIO SOURCE YET: EXPANDED VERY LARGE ARRAY OBSERVATIONS OF THE GRAVITATIONAL LENS SDSS J1004+4112

    International Nuclear Information System (INIS)

    We present new radio observations of the large-separation gravitationally lensed quasar SDSS J1004+4112, taken in a total of 6 hr of observations with the Expanded Very Large Array. The maps reach a thermal noise level of approximately 4 μJy. We detect four of the five lensed images at the 15-35 μJy level, representing a source of intrinsic flux density, after allowing for lensing magnification, of about 1 μJy, intrinsically probably the faintest radio source yet detected. This reinforces the utility of gravitational lensing in potentially allowing us to study nJy-level sources before the advent of the Square Kilometre Array. In an optical observation taken three months after the radio observation, image C is the brightest image, whereas the radio map shows flux density ratios consistent with previous optical observations. Future observations separated by a time delay will give the intrinsic flux ratios of the images in this source.

  1. The gravitational dynamics of galaxies

    Indian Academy of Sciences (India)

    Rajaram Nityananda

    2009-07-01

    The broad area of galactic dynamics is presented for a physics audience, with the requisite astronomy background in outline, and focusing on gravitational effects. The basic underlying model is a large number of particles (which could be stars or dark matter) moving in their self-consistent gravitational potential. The effects of two-particle correlations/scattering, although weak, can be cumulative and hence important for a class of systems such as star clusters which are hence termed collisional. On the larger scale of galaxies, we have collisionless behaviour which is different and in some ways richer. The basic ideas and applications in both these regimes are described, and some issues highlighted in conclusion.

  2. Gravitating multidefects from higher dimensions

    CERN Document Server

    Giovannini, Massimo

    2007-01-01

    Warped configurations admitting pairs of gravitating defects are analyzed. After devising a general method for the construction of multidefects, specific examples are presented in the case of higher-dimensional Einstein-Hilbert gravity. The obtained profiles describe diverse physical situations such as (topological) kink-antikink systems, pairs of non-topological solitons and bound configurations of a kink and of a non-topological soliton. In all the mentioned cases the geometry is always well behaved (all relevant curvature invariants are regular) and tends to five-dimensional anti-de Sitter space-time for large asymptotic values of the bulk coordinate. Particular classes of solutions can be generalized to the framework where the gravity part of the action includes, as a correction, the Euler-Gauss-Bonnet combination. After scrutinizing the structure of the zero modes, the obtained results are compared with conventional gravitating configurations containing a single topological defect.

  3. Bayesian Inference on Gravitational Waves

    Directory of Open Access Journals (Sweden)

    Asad Ali

    2015-12-01

    Full Text Available The Bayesian approach is increasingly becoming popular among the astrophysics data analysis communities. However, the Pakistan statistics communities are unaware of this fertile interaction between the two disciplines. Bayesian methods have been in use to address astronomical problems since the very birth of the Bayes probability in eighteenth century. Today the Bayesian methods for the detection and parameter estimation of gravitational waves have solid theoretical grounds with a strong promise for the realistic applications. This article aims to introduce the Pakistan statistics communities to the applications of Bayesian Monte Carlo methods in the analysis of gravitational wave data with an  overview of the Bayesian signal detection and estimation methods and demonstration by a couple of simplified examples.

  4. Thermal Duality and Gravitational Collapse

    CERN Document Server

    Hewitt, Michael

    2015-01-01

    Thermal duality is a relationship between the behaviour of heterotic string models of the $E(8)x E(8)$ or $SO(32)$ types at inversely related temperatures, a variant of T duality in the Euclidean regime. This duality would have consequences for the nature of the Hagedon transition in these string models. We propose that the vacuum admits a family of deformations in situations where there are closed surfaces of constant area but high radial acceleration (a string regularized version of a Penrose trapped surface), such as would be formed in situations of extreme gravitational collapse. This would allow a radical resolution of the firewall paradox by allowing quantum effects to significantly modify the spacetime geometry around a collapsed object. A string bremsstrahlung process would convert the kinetic energy of infalling matter in extreme gravitational collapse to form a region of the deformed vacuum, which would be equivalent to forming a high temperature string phase. This process might have observable cons...

  5. A gravitating electroweak bag model

    Science.gov (United States)

    Burinskii, Alexander

    2016-02-01

    Gravitational and electromagnetic (EM) field of electron is described by the Kerr-Newman (KN) black hole solution with a topological defect. Regularization of this defect by the Higgs field leads to the smooth source which shares much in common with the known MIT- and SLAC- bag models, but has the advantage, of matching gravitational and electromagnetic fields of the electron. This model is flexible, and the rotating KN bag takes the shape of a thin disk with a circular string positioned on the sharp border of the disk. We consider the lowest excitations of the KN solution and the corresponding deformations of the bag surface, setting a preliminary correspondence with electroweak sector of the SM.

  6. New case of gravitational lensing

    Energy Technology Data Exchange (ETDEWEB)

    Surdej, J.; Swings, J.-P.; Magain, P.; Borgeest, U.; Kayser, R.; Refsdal, S.; Courvoisier, T.J.-L.; Kellermann, K.I.; Kuehr, H.

    1987-10-22

    The authors report a brief description of a gravitational lens system UM673 = Q0142 - 100 = PHL3703. It consists of two images, A and B, separated by 2.2 arc s at a redshift zsub(q) = 2.719. The lensing galaxy has also been found. It lies very near the line connecting the two QSO (quasi-stellar objects) images, approx. 0.8 arc s from the fainter one. Application of gravitational optometry to this system leads to a value Msub(o) or approx. = 2.4 x 10/sup 11/ M solar masses for the mass of the lensing galaxy and to ..delta..t approx. 7 weeks for the most likely travel-time difference between the two light paths to the QSO.

  7. Gravitational waves from compact objects

    Institute of Scientific and Technical Information of China (English)

    José Antonio de Freitas Pacheco

    2010-01-01

    Large ground-based laser beam interferometers are presently in operation both in the USA (LIGO) and in Europe (VIRGO) and potential sources that might be detected by these instruments are revisited. The present generation of detectors does not have a sensitivity high enough to probe a significant volume of the universe and,consequently, predicted event rates are very low. The planned advanced generation of interferometers will probably be able to detect, for the first time, a gravitational signal. Advanced LIGO and EGO instruments are expected to detect few (some): binary coalescences consisting of either two neutron stars, two black holes or a neutron star and a black hole. In space, the sensitivity of the planned LISA spacecraft constellation will allow the detection of the gravitational signals, even within a "pessimistic" range of possible signals, produced during the capture of compact objects by supermassive black holes, at a rate of a few tens per year.

  8. Conformal gravity and "gravitational bubbles"

    CERN Document Server

    Berezin, V A; Eroshenko, Yu N

    2015-01-01

    We describe the general structure of the spherically symmetric solutions in the Weyl conformal gravity. The corresponding Bach equations are derived for the special type of metrics, which can be considered as the representative of the general class. The complete set of the pure vacuum solutions, consisting of two classes, is found. The first one contains the solutions with constant two-dimensional curvature scalar, and the representatives are the famous Robertson--Walker metrics. We called one of them the "gravitational bubbles", which is compact and with zero Weyl tensor. These "gravitational bubbles" are the pure vacuum curved space-times (without any material sources, including the cosmological constant), which are absolutely impossible in General Relativity. This phenomenon makes it easier to create the universe from "nothing". The second class consists of the solutions with varying curvature scalar. We found its representative as the one-parameter family, which can be conformally covered by the thee-para...

  9. Classifying self-gravitating radiations

    CERN Document Server

    Kim, Hyeong-Chan

    2016-01-01

    We study static systems of self-gravitating radiations confined in a sphere by using numerical and analytic calculations. We classify and analyze the solutions systematically. Due to the scaling symmetry, any solution can be represented as a segment of a solution curve on a plane of two-dimensional scale invariant variables. We find that a system can be conveniently parametrized by three parameters representing the solution curve, the scaling, and the system size, instead of the parameters defined at the outer boundary. The solution curves are classified to three types representing regular solutions, conically singular solutions with, and without an object which resembles an event horizon up to causal disconnectedness. For the last type, the behavior of a self-gravitating system is simple enough to allow analytic calculations.

  10. Mansouri-Chang gravitation theory

    Science.gov (United States)

    Pavelle, R.

    1978-01-01

    The gauge theory of gravitation introduced by Mansouri and Chang (1976) is investigated; a symbolic manipulation computer system generates the Mansouri-Chang field equations in various coordinate systems. It is found that all vacuum Einstein spaces are vacuum Mansouri-Chang spaces in four dimensions, though for higher dimensions an Einstein vacuum space is not generally a Mansouri-Chang solution. The possibility that no solutions of the Mansouri-Chang equations are not Einstein vacuum spaces is discussed.

  11. Gravitating Dyons in Vaidya Geometry

    CERN Document Server

    Tripathi, Buddhi Vallabh; Dehnen, Heinz; Purohit, K D

    2014-01-01

    Gravitating monopoles and dyons in Einstein-Yang-Mills (EYM) or Einstein-Yang-Mills-Higgs (EYMH) systems have been extensively studied for various curved spacetimes, including those of black holes. We construct dyonic solutions of the EYMH theory in Vaidya spacetime using a set of generalized Julia-Zee ansatz for the fields. It is found that the dyonic charge is static in nature and it does not contribute to the energy of the null dust.

  12. Cylindrical Collapse and Gravitational Waves

    CERN Document Server

    Herrera, L

    2005-01-01

    We study the matching conditions for a collapsing anisotropic cylindrical perfect fluid, and we show that its radial pressure is non zero on the surface of the cylinder and proportional to the time dependent part of the field produced by the collapsing fluid. This result resembles the one that arises for the radiation - though non-gravitational - in the spherically symmetric collapsing dissipative fluid, in the diffusion approximation.

  13. The wheel of retail gravitation?

    OpenAIRE

    Brown, S.

    1992-01-01

    Reilly's Law of Retail Gravitation ranks among the classics of marketing geography. In this paper an examination of the evolution of Reilly's law is made, the contemporaneous wheel of retailing theory being used as an organisational framework. In line with the wheel, the gravity model commenced as a simple conceptualisation of consumer spatial behaviour, became increasingly sophisticated through time, and thereby created conditions conducive to the reemergence of the basic interaction model. ...

  14. Pulsars revived by gravitational waves

    OpenAIRE

    Lipunov, Vladimir M.; Panchenko, Ivan E.

    1996-01-01

    Binary neutron stars mergers that are expected to be the most powerful source of energy in the Universe definitely exist in nature, as is proven by the observed behavior of the Hulse-Taylor binary radio pulsar. Though most of energy in such events is radiated in gravitational waves, there probably exist several mechanisms giving also electromagnetic radiation. We propose a new one, involving a revival of the radio pulsar several orbital cycles before the merger.

  15. Towards an Alternative Gravitational Theory

    OpenAIRE

    Nieto, J.A.; Beltrán, L. A.

    2014-01-01

    In 1680 Cassini proposed oval curves as alternative trajectories for the visible planets around the sun. The Cassini ovals were of course overshadow by the Kepler's first law (1609), namely the planets move around the sun describing conic orbits. Here we describe the possibility that the Cassini's idea works at larger or smaller scales. Indeed, we consider the Spiric curves (which are a generalization of the Cassini oval) and present the first steps towards a Spiric gravitational theory. We s...

  16. Gravitation, Thermodynamics, and Quantum Theory

    OpenAIRE

    Wald, Robert M.

    1999-01-01

    During the past 30 years, research in general relativity has brought to light strong hints of a very deep and fundamental relationship between gravitation, thermodynamics, and quantum theory. The most striking indication of such a relationship comes from black hole thermodynamics, where it appears that certain laws of black hole mechanics are, in fact, simply the ordinary laws of thermodynamics applied to a system containing a black hole. This article will review the present status of black h...

  17. ALMA Imprint of Intergalactic Dark Structures in the Gravitational Lens SDP.81

    CERN Document Server

    Inoue, Kaiki Taro; Matsushita, Satoki; Chiba, Masashi

    2015-01-01

    We present an analysis of the ALMA long baseline science verification data of the gravitational lens system SDP.81. We fit the positions of the brightest clumps at redshift z=3.042 and a possible AGN component of the lensing galaxy at redshift z=0.2999 in the band 7 continuum image using a canonical lens model, a singular isothermal ellipsoid plus an external shear. Then, we measure the ratio of fluxes in some apertures at the source plane where the lensed images are inversely mapped. We find that the aperture flux ratios of band 7 continuum image are perturbed by 10-20 percent with a significance at 2 ~ 3 sigma level. Moreover, we measure the astrometric shifts of multiply lensed images near the caustic using the CO(8-7) line. Using a lens model best-fitted to the band 7 continuum image, we reconstruct the source image of the CO(8-7) line by taking linear combination of inverted quadruply lensed images. At the 50th channel (rest-frame velocity 28.6 km/s) of the CO(8-7) line, we find an imprint of astrometric...

  18. Study of Gravitational Lens Chromaticity from Ground-based Narrow Band Photometry

    CERN Document Server

    Mosquera, Ana M; Mediavilla, Evencio; Kochanek, Christopher S

    2010-01-01

    We present observations of wavelength-dependent flux ratios for 4 gravitational lens systems (SDSS~J1650+4251, HE~0435$-$1223, FBQ 0951+2635, and Q~0142$-$100) obtained with the Nordic Optical telescope (NOT). The use of narrow band photometry, as well as the excellent seeing conditions during the observations, allow us to set good baselines to study their chromatic behavior. For SDSS~J1650+4251 we determine the extinction curve of the dust in the $z_L=0.58$ lens galaxy, and find that the 2175 \\AA \\ feature is absent. In the case of HE~0435$-$1223 we clearly detect chromatic microlensing. This allows us to estimate the wavelength dependent size of the accretion disk. We found an R-band disk size of $r^{R}_s=13\\pm5$ light days for a linear prior on $r^{R}_s$ and of $r^{R}_s=7\\pm6$ light days for a logarithmic prior. For a power law size-wavelength scaling of $r_s\\propto\\lambda^{p}$, we were able to constrain the value of the exponent to $p=1.3\\pm0.3$ for both $r^{R}_s$ priors, which is in agreement with the te...

  19. Measuring Gravitation Using Polarization Spectroscopy

    Science.gov (United States)

    Matsko, Andrey; Yu, Nan; Maleki, Lute

    2004-01-01

    A proposed method of measuring gravitational acceleration would involve the application of polarization spectroscopy to an ultracold, vertically moving cloud of atoms (an atomic fountain). A related proposed method involving measurements of absorption of light pulses like those used in conventional atomic interferometry would yield an estimate of the number of atoms participating in the interferometric interaction. The basis of the first-mentioned proposed method is that the rotation of polarization of light is affected by the acceleration of atoms along the path of propagation of the light. The rotation of polarization is associated with a phase shift: When an atom moving in a laboratory reference interacts with an electromagnetic wave, the energy levels of the atom are Doppler-shifted, relative to where they would be if the atom were stationary. The Doppler shift gives rise to changes in the detuning of the light from the corresponding atomic transitions. This detuning, in turn, causes the electromagnetic wave to undergo a phase shift that can be measured by conventional means. One would infer the gravitational acceleration and/or the gradient of the gravitational acceleration from the phase measurements.

  20. Modular gravitational reference sensor development

    International Nuclear Information System (INIS)

    The Modular Gravitational Reference Sensor (MGRS) is targeted as a next generation core instrument for both space gravitational wave detection and an array of other precision gravitational experiments in space. The objectives of the NASA funded program are to gain a system perspective of the MGRS, to develop key component technologies, and to establish important test platforms. Our original program was very aggressive in proposing ten areas of research and development. Significant advancements have been made in these areas, and we have met or exceeded the goals for the program set in 2007-2008. Additionally, we have initiated research projects for innovative technologies beyond the original plan. In this paper we will give a balanced overview of progress in MGRS technologies: the two layer sensing and control scheme, trade-off studies of GRS configurations, multiple optical sensor signal processing, optical displacement and angular sensors, differential optical shadow sensing, diffractive optics, proof mass center of mass and moment of inertia measurement, UV LED charge management, proof mass fabrication, thermal control and sensor development, characterization for various proof mass shapes, and alternative charge manage techniques.

  1. Anomalous interactions at a linear collider

    Indian Academy of Sciences (India)

    Sudhansu S Biswal; Debajyoti Choudhury; Rohini M Godbole; Ritesh K Singh

    2007-11-01

    We examine, in a model independent way, the sensitivity of a linear collider to the couplings of a light Higgs boson to a pair of gauge bosons, including the possibility of CP violation. We construct several observables that probe the various possible anomalous couplings. For an intermediate mass Higgs, a collider operating at a center of mass energy of 500 GeV and with an integrated luminosity of 500 fb-1 is shown to be able to constrain the vertex at the few per cent level, with even higher sensitivity for some of the couplings. However, lack of sufficient number of observables as well as contamination from the vertex limits the precision to which anomalous part of the coupling can be probed.

  2. Petrology of Anomalous Eucrite QUE 94484

    Science.gov (United States)

    Mittlefehldt, D. W.; Peng, Z. X.

    2015-01-01

    Most mafic achondrites are broadly "eucritic", being composed of ferroan low-Ca clinopyroxene, high-Ca plagioclase, a silica phase, ilmenite and accessory phases. Their characteristics indicate that eucrite-like basalts formed on asteroids of similar composition under similar petrologic conditions (T, P, fO2). Some eucrite-like basalts have isotopic compositions and petrologic characteristics consistent with formation on different parent asteroids (e.g., Ibitira, NWA 011). Others show small isotopic differences but no distinguishing petrological characteristics (e.g., Caldera, Pasamonte). We have begun a study of anomalous eucrite-like achondrites in an effort to seek resolution to the issues: Did the eucrite parent asteroid fail to homogenize via a magma-ocean stage, thus explaining outliers like Pasamonte? How many parent asteroids are represented by these basalts? Here we present preliminary petrologic information on anomalous basaltic eucrite QUE 94484.

  3. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....

  4. Equilibrium fluctuation theorems compatible with anomalous response

    Science.gov (United States)

    Velazquez, L.; Curilef, S.

    2010-12-01

    Previously, we have derived a generalization of the canonical fluctuation relation between heat capacity and energy fluctuations C = β2langδU2rang, which is able to describe the existence of macrostates with negative heat capacities C < 0. In this work, we extend our previous results for an equilibrium situation with several control parameters to account for the existence of states with anomalous values in other response functions. Our analysis leads to the derivation of three different equilibrium fluctuation theorems: the fundamental and the complementary fluctuation theorems, which represent the generalization of two fluctuation identities already obtained in previous works, and the associated fluctuation theorem, a result that has no counterpart in the framework of Boltzmann-Gibbs distributions. These results are applied to study the anomalous susceptibility of a ferromagnetic system, in particular, the case of the 2D Ising model.

  5. Anomalous transport theory for toroidal helical plasmas

    International Nuclear Information System (INIS)

    Anomalous transport coefficients in toroidal helical plasmas are studied, based on the innovative theoretical method. The self-sustained turbulence is analyzed by balancing the nonlinear growth due to the current diffusivity with the nonlinear damping by the ion viscosity and thermal conductivity. Interchange and ballooning mode turbulence is investigated, and the geometrical dependence of the anomalous transport coefficient is clarified. Variation of transport owing to the geometrical difference in toroidal helical plasmas is illustrated. The mechanism for confinement improvement is searched for. To verify the nonlinear destabilization and the self-sustained state, the nonlinear simulation of the interchange mode turbulence is performed in a sheared slab. It is demonstrated that the nonlinear enhancement of the growth rate occurs when the fluctuation amplitude exceeds the critical level. In the saturation stage, the fluctuation level becomes higher associated with the enhanced nonlinear growth. (author)

  6. Anomalous Hall effect in Weyl superconductors

    Science.gov (United States)

    Bednik, G.; Zyuzin, A. A.; Burkov, A. A.

    2016-08-01

    We present a theory of the anomalous Hall effect in a topological Weyl superconductor with broken time reversal symmetry. Specifically, we consider a ferromagnetic Weyl metal with two Weyl nodes of opposite chirality near the Fermi energy. In the presence of inversion symmetry, such a metal experiences a weak-coupling Bardeen–Cooper–Schrieffer instability, with pairing of parity-related eigenstates. Due to the nonzero topological charge, carried by the Weyl nodes, such a superconductor is necessarily topologically nontrivial, with Majorana surface states coexisting with the Fermi arcs of the normal Weyl metal. We demonstrate that, surprisingly, the anomalous Hall conductivity of such a superconducting Weyl metal coincides with that of a nonsuperconducting one, under certain conditions, in spite of the nonconservation of charge in a superconductor. We relate this to the existence of an extra (nearly) conserved quantity in a Weyl metal, the chiral charge.

  7. Examination of anomalous self-experience

    DEFF Research Database (Denmark)

    Raballo, Andrea; Parnas, Josef

    2012-01-01

    A growing body of evidence points to the clinical and heuristic value of anomalous subjective experiences (ASEs) for the characterization of schizophrenia spectrum vulnerability and early detection purposes. In particular, a subgroup of ASEs, entailing basic disorders of self-awareness (self....... Here, we present the initial normative data and psychometric properties of a newly developed instrument (Examination of Anomalous Self-experience [EASE]), specifically designed to support the psychopathological exploration of SDs in both research and "real world" clinical settings. Our results support...... the clinical validity of the EASE as a tool for assessing anomalies of self-awareness (SDs) and lend credit to the translational potential of a phenomenological exploration of the subjective experience of vulnerability to schizophrenia....

  8. Probing anomalous gauge boson couplings at LEP

    International Nuclear Information System (INIS)

    We bound anomalous gauge boson couplings using LEP data for the Z → bar ∫∫ partial widths. We use an effective field theory formalism to compute the one-loop corrections resulting from non-standard model three and four gauge boson vertices. We find that measurements at LEP constrain the three gauge boson couplings at a level comparable to that obtainable at LEPII

  9. Anomalous Mirror Symmetry Generated by Optical Illusion

    Directory of Open Access Journals (Sweden)

    Kokichi Sugihara

    2016-04-01

    Full Text Available This paper introduces a new concept of mirror symmetry, called “anomalous mirror symmetry”, which is physically impossible but can be perceived by human vision systems because of optical illusion. This symmetry is characterized geometrically and a method for creating cylindrical surfaces that create this symmetry is constructed. Examples of solid objects constructed by a 3D printer are also shown.

  10. Anomalous velocity distributions in active Brownian suspensions

    OpenAIRE

    Fiege, Andrea; Vollmayr-Lee, Benjamin; Zippelius, Annette

    2013-01-01

    Large scale simulations and analytical theory have been combined to obtain the non-equilibrium velocity distribution, $f(v)$, of randomly accelerated particles in suspension. The simulations are based on an event-driven algorithm, generalised to include friction. They reveal strongly anomalous but largely universal distributions which are independent of volume fraction and collision processes, which suggests a one-particle model should capture all the essential features. We have formulated th...

  11. Electroweak Baryogenesis with Anomalous Higgs Couplings

    Science.gov (United States)

    Kobakhidze, Archil; Wu, Lei; Yue, Jason

    2016-07-01

    In non-linear realisation of the electroweak gauge symmetry, the LHC Higgs boson can be assumed to be a singlet under SU(2)L ⊗ U(1)Y. In such scenario, the Standard Model particle content can be kept but new sets of couplings are allowed. We identify a range of anomalous Higgs cubic and the 𝒞𝒫-violating Higgs-top quark couplings that leads to first order phase transition and successful baryogenesis at the electroweak scale.

  12. Anomalous free energy changes induced by topology.

    Science.gov (United States)

    Tang, Ying; Yuan, Ruoshi; Ao, Ping

    2015-12-01

    We report that nontrivial topology of a driven Brownian particle restricted on a ring leads to anomalous behaviors on free energy change. Starting from steady states with identical distribution and current on the ring, free energy changes are distinct and nonperiodic after the system is driven by the same periodic force protocol. We demonstrate our observation in examples through both exact solutions and numerical simulations. The free energy calculated here can be measured in recent experimental systems. PMID:26764654

  13. Anomalous diffusions induced by enhancement of memory

    OpenAIRE

    Kim, Hyun-Joo

    2014-01-01

    We introduced simple microscopic non-Markovian walk models which describe underlying mechanism of anomalous diffusions. In the models, we considered the competitions between randomness and memory effects of previous history by introducing the probability parameters. The memory effects were considered in two aspects, one is the perfect memory of whole history and the other is the latest memory improved with time. In the perfect memory model superdiffusion was induced with the relation the Hurs...

  14. Anomalous dissolution of metals and chemical corrosion

    Directory of Open Access Journals (Sweden)

    DRAGUTIN M. DRAZIC

    2005-03-01

    Full Text Available An overview is given of the anomalous behavior of some metals, in particular Fe and Cr, in acidic aqueous solutions during anodic dissolution. The anomaly is recognizable by the fact that during anodic dissolutionmore material dissolves than would be expected from the Faraday law with the use of the expected valence of the formed ions. Mechanical disintegration, gas bubble blocking, hydrogen embrittlement, passive layer cracking and other possible reasons for such behavior have been discussed. It was shown, as suggested by Kolotyrkin and coworkers, that the reason can be, also, the chemical reaction in which H2O molecules with the metal form metal ions and gaseous H2 in a potential independent process. It occurs simultaneously with the electrochemical corrosion process, but the electrochemical process controls the corrosion potential. On the example of Cr in acid solution itwas shown that the reason for the anomalous behavior is dominantly chemical dissolution, which is considerably faster than the electrochemical corrosion, and that the increasing temperature favors chemical reaction, while the other possible reasons for the anomalous behavior are of negligible effect. This effect is much smaller in the case of Fe, but exists. The possible role of the chemical dissolution reacton and hydrogen evolution during pitting of steels and Al and stress corrosion cracking or corrosion fatigue are discussed.

  15. Anomalous diffusion induced by enhancement of memory

    Science.gov (United States)

    Kim, Hyun-Joo

    2014-07-01

    We introduced simple microscopic non-Markovian walk models which describe the underlying mechanism of anomalous diffusions. In the models, we considered the competitions between randomness and memory effects of previous history by introducing the probability parameters. The memory effects were considered in two aspects: one is the perfect memory of whole history and the other is the latest memory enhanced with time. In the perfect memory model superdiffusion was induced with the relation of the Hurst exponent H to the controlling parameter p as H =p for p >1/2, while in the latest memory enhancement models, anomalous diffusions involving both superdiffusion and subdiffusion were induced with the relations H =(1+α)/2 and H =(1-α)/2 for 0≤α≤1, where α is the parameter controlling the degree of the latest memory enhancement. Also we found that, although the latest memory was only considered, the memory improved with time results in the long-range correlations between steps and the correlations increase as time goes on. Thus we suggest the memory enhancement as a key origin describing anomalous diffusions.

  16. Anomalous water drop bouncing on a nanotextured surface by the Leidenfrost levitation

    Science.gov (United States)

    Lee, Doo Jin; Song, Young Seok

    2016-05-01

    We report an anomalous liquid drop bouncing phenomenon that is generated by the Leidenfrost levitation due to a vapor layer reducing energy dissipation during the collision. The Leidenfrost levitation of water drops on both a hydrophobic surface and nanotextured Cassie surface is investigated. When the water drop is positioned onto the hydrophobic surface, a superhydrophobic feature is observed by the levitation effect due to the vapor film, which results in a slow evaporation of the drop due to the low thermal conductivity of the vapor layer that inhibits heat transfer between the heated surface and the water drop. In contrast, for the nanotextured surface, the water drop can bounce off after impact on the surface when it overcomes gravitational and adhesion forces. The spontaneous water drop bouncing on the nanotextured surface is powered by the combination effect of the Leidenfrost levitation and the non-wetting Cassie state.

  17. Nonlocal gravity: damping of linearized gravitational waves

    International Nuclear Information System (INIS)

    In nonlocal general relativity, linearized gravitational waves are damped as they propagate from the source to the receiver in the Minkowski vacuum. Nonlocal gravity is a generalization of Einstein's theory of gravitation in which nonlocality is due to the gravitational memory of past events. That nonlocal gravity is dissipative is demonstrated in this paper within certain approximation schemes. The gravitational memory drag leads to the decay of the amplitude of gravitational waves given by the exponential damping factor exp (− t/τ), where τ depends on the kernel of nonlocal gravity. The damping time τ is estimated for gravitational waves of current observational interest and is found to be of the order of, or longer than, the age of the universe. (paper)

  18. Gravitational Gauge Interactions of Scalar Field

    Institute of Scientific and Technical Information of China (English)

    WUNing

    2003-01-01

    Quantum gauge theory of gravity is formulated based on gauge principle. Because the Lagrangian has strict local gravitational gauge symmetry, gravitational gauge theory is a perturbatively renormalizable quantum theory. Gravitational gauge interactions of scalar field are studied in this paper. In quantum gauge theory of gravity, scalar field minimal couples to gravitational field through gravitational gauge covariant derivative. Comparing the Lagrangian for scalar field in quantum gauge theory of gravity with the corresponding Lagrangian in quantum fields in curved space-time, the definition for metric in curved space-time in geometry picture of gravity can be obtained, which is expressed by gravitational gauge field. In classical level, the Lagrangian and Hamiltonian approaches are also discussed.

  19. Gravitational compensation for the LISA pathfinder

    International Nuclear Information System (INIS)

    This paper addresses the problem of compensating self-gravity for the LISA Technology Package. Massive components onboard the spacecraft produce a gravitational imbalance on the free-falling test masses. We present here a compensation scheme to reduce the gravitational forces, torques, stiffness and cross-talk to values within requirements. Gravitational analysis and subsequent compensation are needed to limit the gravitational imbalances in order to reduce the force noise and force gradients associated with the electrostatic actuation that must compensate any residual gravitational imbalances. Starting from an educated guess based on simple Newtonian arguments, we present the approximate shapes of a compensation block solution which minimizes the residual gravitational imbalance and stiffness while adding a minimum of mass

  20. Gravitational compensation for the LISA pathfinder

    Energy Technology Data Exchange (ETDEWEB)

    Armano, M [Dipartimento di Fisica, Universita di Trento and INFN, Sezione di Padova, Gruppo Collegato di Trento, I-38050, Povo, Trento (Italy); Dipartimento di Fisica, Universita degli Studi dell' Insubria, via Valleggio, 11, 22100 Como (Italy); Bortoluzzi, D [Dipartimento di Ingegneria Meccanica Strutturale, Universita di Trento, Mesiano, Trento (Italy); Hoyle, C D [Dipartimento di Fisica, Universita di Trento and INFN, Sezione di Padova, Gruppo Collegato di Trento, I-38050, Povo, Trento (Italy); Vitale, S [Dipartimento di Fisica, Universita di Trento and INFN, Sezione di Padova, Gruppo Collegato di Trento, I-38050, Povo, Trento (Italy)

    2005-05-21

    This paper addresses the problem of compensating self-gravity for the LISA Technology Package. Massive components onboard the spacecraft produce a gravitational imbalance on the free-falling test masses. We present here a compensation scheme to reduce the gravitational forces, torques, stiffness and cross-talk to values within requirements. Gravitational analysis and subsequent compensation are needed to limit the gravitational imbalances in order to reduce the force noise and force gradients associated with the electrostatic actuation that must compensate any residual gravitational imbalances. Starting from an educated guess based on simple Newtonian arguments, we present the approximate shapes of a compensation block solution which minimizes the residual gravitational imbalance and stiffness while adding a minimum of mass.

  1. Gravitational Lensing: Strong, Weak and Micro

    CERN Document Server

    Schneider, Peter; Wambsganss, Joachim

    2006-01-01

    The theory, observations, and applications of gravitational lensing constitute one of the most rapidly growing branches of astrophysics. The gravitational deflection of light generated by mass concentrations along a light path produces magnification, multiplicity, and distortion of images and delays photon propagation from one line of sight relative to another. The huge amount of scientific work on gravitational lensing produced over the last decade has clearly revealed its already substantial and wide impact and its potential for future astrophysical applications. The up-to-date contributions in this book are based on the lecture notes of the 33rd Saas–Fee Advanced Course of the Swiss Society of Astronomy and Astrophysics, entitled Gravitational Lensing: Strong, Weak, and Micro. The book comprises four complementary parts, written by leading experts in the field, constituting a genuine textbook about gravitational lensing: • Peter Schneider – Part 1: Introduction to Gravitational Lensing and Cosmology ...

  2. Gravitational Gauge Interactions of Scalar Field

    Institute of Scientific and Technical Information of China (English)

    WU Ning

    2003-01-01

    Quantum gauge theory of gravity is formulated based on gauge principle. Because the Lagrangian hasstrict local gravitational gauge symmetry, gravitational gauge theory is a perturbatively renormalizable quantum theory.Gravitational gauge interactions of scalar field are studied in this paper. In quantum gauge theory of gravity, scalar fieldminimal couples to gravitational field through gravitational gauge covariant derivative. Comparing the Lagrangian forscalar field in quantum gauge theory of gravity with the corresponding Lagrangian in quantum fields in curved space-time, the definition for metric in curved space-time in geometry picture of gravity can be obtained, which is expressedby gravitational gauge field. In classical level, the Lagrangian and Hamiltonian approaches are also discussed.

  3. Universal Gravitation as Lorentz-covariant Dynamics

    CERN Document Server

    Kauffmann, Steven Kenneth

    2014-01-01

    Einstein's equivalence principle implies that the acceleration of a particle in a "specified" gravitational field is independent of its mass. While this is certainly true to great accuracy for bodies we observe in the Earth's gravitational field, a hypothetical body of mass comparable to the Earth's would perceptibly cause the Earth to fall toward it, which would feed back into the strength as a function of time of the Earth's gravitational field affecting that body. In short, Einstein's equivalence principle isn't exact, but is an approximation that ignores recoil of the "specified" gravitational field, which sheds light on why general relativity has no clearly delineated native embodiment of conserved four-momentum. Einstein's 1905 relativity of course doesn't have the inexactitudes he unwittingly built into GR, so it is natural to explore a Lorentz-covariant gravitational theory patterned directly on electromagnetism, wherein a system's zero-divergence overall stress-energy, including all gravitational fee...

  4. H2/(Ar+H2)流量比对AZO薄膜结构及光电性能的影响%Effect of H2/(Ar+H2)flux ratio on structure and optical-electrical properties of AZO thin films

    Institute of Scientific and Technical Information of China (English)

    朱胜君; 王俊; 李念; 李涛涛; 吴隽; 祝柏林

    2012-01-01

    在Ar+ H2气氛下,用RF磁控溅射法在室温下制备Al掺杂的ZnO(AZO)薄膜,研究H2/(Ar+H2)流量比对薄膜结构和光电性能的影响.结果表明,在沉积气氛中引入H2可以提高AZO薄膜的结晶质量,降低AZO薄膜的电阻率,提高其霍尔迁移率和载流子浓度;H2/(Ar+ H2)流量比为5%时,AZO薄膜的最小电阻率为1.58×10-3 Ω·cm,最大霍尔迁移率和载流子浓度分别为13.17 cm2·(V· s)-1和3.01×1020 cm-3;AZO薄膜在可见光范围内平均透光率大于85.7%.%Al-doped ZnO thin films (AZO) were deposited in Ar+H2 atmosphere by RF magnetron sputtering at room temperature. The effect of H2/(Ar+H2) flux ratio on structure and optical-electrical properties of AZO films were investigated with XRD, SEM, Hall effect instrument, and UV visible spectrophotometer. The results show that H2 introduction into deposition atmosphere can improve the crystallite quality of the AZO films, greatly reduce the electrical resistivity and improve Hall mobility and carrier concentration of the films. When H2/(Ar+H2) flux ratio is 5%, deposited AZO film has the minimum resistivity of 1. 58× 10-3 Ω · cm with Hall mobility.at 13. 17 cm2 V-1 s-1 and carrier concentration at 3. 01 × 10 20 cm-3, and its average transmittance in the visible light range is over 85. 7%. The results suggest that AZO films deposited in Ar+H2 atmosphere at room temperature are suitable for application in solar cells and organic light emitting diodes as transparent conductive electrode layers.

  5. Electromagnetic Effects in Superconductors in Gravitational Field

    OpenAIRE

    Ahmedov, B. J.; Kagramanova, V. G.

    2006-01-01

    The general relativistic modifications to the resistive state in superconductors of second type in the presence of a stationary gravitational field are studied. Some superconducting devices that can measure the gravitational field by its red-shift effect on the frequency of radiation are suggested. It has been shown that by varying the orientation of a superconductor with respect to the earth gravitational field, a corresponding varying contribution to AC Josephson frequency would be added by...

  6. Gravitational waves from binary black holes

    Indian Academy of Sciences (India)

    Bala R Iyer

    2011-07-01

    It is almost a century since Einstein predicted the existence of gravitational waves as one of the consequences of his general theory of relativity. A brief historical overview including Chandrasekhar’s contribution to the subject is first presented. The current status of the experimental search for gravitational waves and the attendant theoretical insights into the two-body problem in general relativity arising from computations of gravitational waves from binary black holes are then broadly reviewed.

  7. Thermal gravitational waves in accelerating universe

    OpenAIRE

    B Ghayour

    2013-01-01

    Gravitational waves are considered in thermal vacuum state. The amplitude and spectral energy density of gravitational waves are found enhanced in thermal vacuum state compared to its zero temperature counterpart. Therefore, the allowed amount of enhancement depends on the upper bound of WMAP-5 and WMAP-7 for the amplitude and spectral energy density of gravitational waves. The enhancement of amplitude and spectral energy density of the waves in thermal vacuum state is consistent with curren...

  8. Gravitational Couplings on D-brane Revisited

    CERN Document Server

    Ghodsi, Ahmad

    2016-01-01

    Gravitational couplings in bulk space-time include those terms which are fixed by scattering amplitude of strings and ambiguous terms that are coming from the field redefinitions. These field redefinitions can be fixed in the bulk by ghost-free condition. In this paper we have revised the effective gravitational couplings on D-branes by including the field redefinitions. We find the gravitational effective action up to $\\alpha'^2$-order.

  9. Black Holes and Gravitational Properties of Antimatter

    OpenAIRE

    Hajdukovic, Dragan Slavkov

    2006-01-01

    The gravitational properties of antimatter are still a secret of nature. One outstanding possibility is that there is a gravitational repulsion between matter and antimatter (in short we call it antigravity). We argue that in the case of antigravity the collapse of a black hole doesn't end with singularity and that deep inside the horizon, the gravitational field may be sufficiently strong to create (from the vacuum) neutrino-antineutrino pairs of all flavours. The created antineutrinos (neut...

  10. Decoherence measure by gravitational wave interferometers

    OpenAIRE

    Mino, Yasushi

    2008-01-01

    We consider the possibility to measure the quantum decoherence using gravitational wave interferometers. Gravitational wave interferometers create the superposition state of photons and measure the interference of the photon state. If the decoherence occurs, the interference of the photon state vanishes and it can be measured by the interferometers. As examples of decoherence mechanisms, we consider 1) decoherence by spontaneous localization, 2) gravitational decoherence and 3) decoherence by...

  11. Einstein and Gravitational Waves 1936-1938

    CERN Document Server

    Weinstein, Galina

    2016-01-01

    Around 1936, Einstein wrote to his close friend Max Born telling him that, together with Nathan Rosen, he had arrived at the interesting result that gravitational waves did not exist, though they had been assumed a certainty to the first approximation. He finally had found a mistake in his 1936 paper with Rosen and believed that gravitational waves do exist. However, in 1938, Einstein again obtained the result that there could be no gravitational waves!

  12. Gravitational Model of the Three Elements Theory

    OpenAIRE

    Frederic Lassiaille

    2012-01-01

    The gravitational model of the three elements theory is an alternative theory to dark matter. It uses a modification of Newton’s law in order to explain gravitational mysteries. The results of this model are explanations for the dark matter mysteries, and the Pioneer anomaly. The disparity of the gravitational constant measurements might also be explained. Concerning the Earth flyby anomalies, the theoretical order of magnitude is the same as the experimental one. A very small change of the p...

  13. Physics, Astrophysics and Cosmology with Gravitational Waves

    Directory of Open Access Journals (Sweden)

    Sathyaprakash B. S.

    2009-03-01

    Full Text Available Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers, and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.

  14. Gravitational Wave Astrophysics: Opening the New Frontier

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    A new era in astronomy will begin when the gravitational wave window onto the universe opens in approx. 5 years, as ground-based detectors make the first detections in the high-frequency regime. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources - such as masses, spins, luminosity distances, and orbital parameters - through dense, obscured regions across cosmic time. This talk will explore gravitational waves as cosmic messengers, highlighting key sources and opportunities for multi-messenger astronomy across the gravitational wave spectrum.

  15. Astrophysical Gravitational Wave Sources Literature Catalog

    Data.gov (United States)

    National Aeronautics and Space Administration — Numerically-generated gravitational waveforms for circular inspiral into Kerr black holes. These waveforms were developed using Scott Hughes' black hole...

  16. S-matrix theory for gravitational field

    International Nuclear Information System (INIS)

    Major results of the investigation conducted on the quantum theory of the gravitational field and reported to the conference are summarized. The S matrix has been constructed in the most general class of gauges including relativistic ones. The causes of the failure to apply the proper-time regularization technique to gravitational interaction are considered. The corrected and improved proper-time method makes it possible to obtain the universal expression for one-loop divergences in and arbitrary system of gravitational fields. Under the assumption of mass-shell renormalizability the quantum theory of the gravitational field is asymptotically free

  17. Constraint on modified dispersion relations for gravitational waves from gravitational Cherenkov radiation

    OpenAIRE

    Kiyota, Satoshi; YAMAMOTO Kazuhiro

    2015-01-01

    We investigate the hypothetical process of gravitational Cherenkov radiation, which may occur in modified gravity theories. We obtain a useful constraint on a modified dispersion relation for propagating modes of gravitational waves, which could be predicted as a consequence of violation of the Lorentz invariance in modified theories of gravity. The constraint from gravitational Cherenkov radiation and that from direct measurements of the gravitational waves emitted by a compact binary system...

  18. Gravitational wave radiometry: Mapping a stochastic gravitational wave background

    CERN Document Server

    Mitra, Sanjit; Souradeep, Tarun; Lazzarini, Albert; Mandic, Vuk; Bose, Sukanta; Ballmer, Stefan

    2007-01-01

    The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either of cosmological or astrophysical origin, bears a strong semblance to the analysis of CMB anisotropy and polarization. The basic statistic we use is the cross-correlation between the data from a pair of detectors. In order to `point' the pair of detectors at different locations one must suitably delay the signal by the amount it takes for the gravitational waves (GW) to travel to both detectors corresponding to a source direction. Then the raw (observed) sky map of the SGWB is the signal convolved with a beam response function that varies with location in the sky. We first present a thorough analytic understanding of the structure of the beam response function using an analytic approach employing the stationary phase approximation. The true sky map is obtained by numerically deconvolving the beam function in the integral (convolution) equation. We adopt the maximum likelihood framework to estimate the true sky...

  19. Testing Fundamental Gravitation in Space

    Energy Technology Data Exchange (ETDEWEB)

    Turyshev, Slava G.

    2013-10-15

    General theory of relativity is a standard theory of gravitation; as such, it is used to describe gravity when the problems in astronomy, astrophysics, cosmology, and fundamental physics are concerned. The theory is also relied upon in many modern applications involving spacecraft navigation, geodesy, and time transfer. Here we review the foundations of general relativity and discuss its current empirical status. We describe both the theoretical motivation and the scientific progress that may result from the new generation of high-precision tests that are anticipated in the near future.

  20. Quasi-Local Gravitational Energy

    OpenAIRE

    Hayward, Sean A.

    1993-01-01

    A dynamically preferred quasi-local definition of gravitational energy is given in terms of the Hamiltonian of a `2+2' formulation of general relativity. The energy is well-defined for any compact orientable spatial 2-surface, and depends on the fundamental forms only. The energy is zero for any surface in flat spacetime, and reduces to the Hawking mass in the absence of shear and twist. For asymptotically flat spacetimes, the energy tends to the Bondi mass at null infinity and the \\ADM mass ...

  1. Gravitational effects on inflaton decay

    Energy Technology Data Exchange (ETDEWEB)

    Ema, Yohei; Jinno, Ryusuke; Mukaida, Kyohei [Department of Physics, University of Tokyo,Tokyo 113-0033 (Japan); Nakayama, Kazunori [Department of Physics, University of Tokyo,Tokyo 113-0033 (Japan); Kavli IPMU, TODIAS, University of Tokyo,Kashiwa 277-8583 (Japan)

    2015-05-22

    We point out that the inflaton inevitably couples to all non-conformally coupled matters gravitationally through an oscillation in the Hubble parameter or the cosmic scale factor. It leads to particle production during the inflaton oscillation regime, which is most efficient just after inflation. Moreover, the analysis is extended to the model with non-minimal inflaton couplings to gravity, in which the Hubble parameter oscillates more violently. We apply our results to the graviton production by the inflaton: gravitons are also produced just after inflation, but the non-minimal coupling does not induce inflaton decay into the graviton pair.

  2. The Scales of Gravitational Lensing

    CERN Document Server

    De Paolis, Francesco; Ingrosso, Gabriele; Manni, Luigi; Nucita, Achille; Strafella, Francesco

    2016-01-01

    After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge) of supermassive black holes in the center of ours and nearby galaxies.

  3. Moduli destabilization via gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dong-il [Sogang Univ., Seoul (Korea, Republic of). Center for Quantum Spacetime; Pedro, Francisco G. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; Yeom, Dong-han [Sogang Univ., Seoul (Korea, Republic of). Center for Quantum Spacetime; Kyoto Univ. (Japan). Yukawa Inst. for Theoretical Physics

    2013-06-15

    We examine the interplay between gravitational collapse and moduli stability in the context of black hole formation. We perform numerical simulations of the collapse using the double null formalism and show that the very dense regions one expects to find in the process of black hole formation are able to destabilize the volume modulus. We establish that the effects of the destabilization will be visible to an observer at infinity, opening up a window to a region in spacetime where standard model's couplings and masses can differ significantly from their background values.

  4. The Scales of Gravitational Lensing

    Directory of Open Access Journals (Sweden)

    Francesco De Paolis

    2016-03-01

    Full Text Available After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge of supermassive black holes in the center of ours and nearby galaxies.

  5. Gravitational Entropy and Global Structure

    CERN Document Server

    Hawking, Stephen William

    1999-01-01

    The underlying reason for the existence of gravitational entropy is traced to the impossibility of foliating topologically non-trivial Euclidean spacetimes with a time function to give a unitary Hamiltonian evolution. In $d$ dimensions the entropy can be expressed in terms of the $d-2$ obstructions to foliation, bolts and Misner strings, by a universal formula. We illustrate with a number of examples including spaces with nut charge. In these cases, the entropy is not just a quarter the area of the bolt, as it is for black holes.

  6. Gravitational entropy and global structure

    Science.gov (United States)

    Hawking, S. W.; Hunter, C. J.

    1999-02-01

    The underlying reason for the existence of gravitational entropy is traced to the impossibility of foliating topologically non-trivial Euclidean spacetimes with a time function to give a unitary Hamiltonian evolution. In d dimensions the entropy can be expressed in terms of the d-2 obstructions to foliation, bolts and Misner strings, by a universal formula. We illustrate with a number of examples including spaces with nut charge. In these cases, the entropy is not just a quarter the area of the bolt, as it is for black holes.

  7. $f(T)$ gravitational baryogenesis

    CERN Document Server

    Oikonomou, V K

    2016-01-01

    We investigate the gravitational baryogenesis mechanism in a universe governed by $f(T)$ gravity. We consider two possible baryogenesis terms, and we calculate the resulting baryon-to-entropy ratio in the case where the background cosmology is determined by either simple teleparallel gravity or by three specific, viable, $f(T)$ models. As we show, $f(T)$ gravity can provide a baryogenesis mechanism in agreement with observations. Reversely, one can use the observed value of baryon-to-entropy ratio in order to constrain the various models.

  8. Moduli destabilization via gravitational collapse

    International Nuclear Information System (INIS)

    We examine the interplay between gravitational collapse and moduli stability in the context of black hole formation. We perform numerical simulations of the collapse using the double null formalism and show that the very dense regions one expects to find in the process of black hole formation are able to destabilize the volume modulus. We establish that the effects of the destabilization will be visible to an observer at infinity, opening up a window to a region in spacetime where standard model's couplings and masses can differ significantly from their background values.

  9. Gravitational Instability of a Kink

    OpenAIRE

    Barreto, W.; Gomez, R.; Lehner, L.; Winicour, J.

    2005-01-01

    We study the equilibria of a self-gravitating scalar field in the region outside a reflecting barrier. By introducing a potential difference between the barrier and infinity, we create a kink which cannot decay to a zero energy state. In the realm of small amplitude, the kink decays to a known static solution of the Einstein-Klein-Gordon equation. However, for larger kinks the static equilibria are degenerate, forming a system with two energy levels. The upper level is unstable and, under sma...

  10. Testing Fundamental Gravitation in Space

    International Nuclear Information System (INIS)

    General theory of relativity is a standard theory of gravitation; as such, it is used to describe gravity when the problems in astronomy, astrophysics, cosmology, and fundamental physics are concerned. The theory is also relied upon in many modern applications involving spacecraft navigation, geodesy, and time transfer. Here we review the foundations of general relativity and discuss its current empirical status. We describe both the theoretical motivation and the scientific progress that may result from the new generation of high-precision tests that are anticipated in the near future

  11. Bound orbits and gravitational theory

    OpenAIRE

    Dadhich, Naresh; Ghosh, Sushant G.(School of Mathematical Sciences, University of KwaZulu-Natal, Westville, 4000, Durban, South Africa); Jhingan, Sanjay

    2013-01-01

    It can be easily shown that bound orbits around a static source can exist only in 4 dimension and in none else for any long range force. This is so not only for Maxwell's electromagnetic and Newton's gravity but also for Einstein's gravitation theory. In contrast to Maxwell's electrodynamics and Newton's gravity, GR has a natural higher dimensional generalization in Lovelock gravity which remarkably admits bound orbits around a static black hole in all even d=2N+2 dimensions where $N$ is degr...

  12. Horizon Thermodynamics and Gravitational Tension

    OpenAIRE

    Widom, A.; Swain, J.; Srivastava, Y. N.

    2016-01-01

    We consider the thermodynamics of a horizon surface from the viewpoint of the vacuum tension $\\tau =(c^4/4G )$. Numerically, $\\tau \\approx 3.026\\times 10^{43}$ Newton. In order of magnitude, this is the tension that has been proposed for microscopic string models of gravity. However, after decades of hard work on string theory models of gravity, there is no firm scientific evidence that such models of gravity apply empirically. Our purpose is thereby to discuss the gravitational tension in te...

  13. Spherically-symmetric gravitational fields in the metric-affine gauge theory of gravitation

    OpenAIRE

    Minkevich, A. V.; Vasilevski, Yu. G.

    2003-01-01

    Geometric structure of spherically-symmetric space-time in metric-affine gauge theory of gravity is studied. Restrictions on curvature tensor and Bianchi identities are obtained. By using certain simple gravitational Lagrangian the solution of gravitational equations for vacuum spherically-symmetric gravitational field is obtained.

  14. A Possible Interpretation on Distance-Dependent Effect of Gravitational Constant in Newton's Theory of Gravitation

    Institute of Scientific and Technical Information of China (English)

    QIAN Shang-Wu

    2005-01-01

    Based on the new metric theory of gravitation suggested by the author of this article, it gives a possible theoretical interpretation on the famous experiment done by D.R. Long in 1976, i.e. the distance-dependent effect of the gravitational constant in Newton's theory of gravitation.

  15. Effects on light propagating in an electromagnetized vacuum, as predicted by a particular class of scalar-tensor theory of gravitation

    Science.gov (United States)

    Raptis, T. E.; Minotti, F. O.

    2013-12-01

    The effect of static electromagnetic fields on the propagation of light is analyzed in the context of a particular class of scalar-tensor gravitational theories. It is found that for appropriate field configurations and light polarization, anomalous amplitude variations of the light as it propagates in either a magnetized or an electrified vacuum are strong enough to be detectable in relatively simple laboratory experiments.

  16. Effects on light propagating in an electromagnetized vacuum, as predicted by a particular class of scalar–tensor theory of gravitation

    International Nuclear Information System (INIS)

    The effect of static electromagnetic fields on the propagation of light is analyzed in the context of a particular class of scalar–tensor gravitational theories. It is found that for appropriate field configurations and light polarization, anomalous amplitude variations of the light as it propagates in either a magnetized or an electrified vacuum are strong enough to be detectable in relatively simple laboratory experiments. (paper)

  17. Anomalous Subsidence at Rifted Continental Margins: Distinguishing Mantle Dynamic Topography from Anomalous Oceanic Crustal Thickness

    Science.gov (United States)

    Cowie, L.; Kusznir, N. J.

    2012-12-01

    It has been proposed that some continental rifted margins have anomalous subsidence histories and that at breakup they were elevated at shallower bathymetries than the isostatic response of classical rift models (McKenzie 1978) would predict. The existence of anomalous syn or post breakup subsidence of this form would have important implications for our understanding of the geodynamics of continental breakup and rifted continental margin formation, margin subsidence history and the evolution of syn and post breakup depositional systems. We have investigated three rifted continental margins; the Gulf of Aden, Galicia Bank and the Gulf of Lions, to determine whether the oceanic crust in the ocean-continent transition of these margins has present day anomalous subsidence and if so, whether it is caused by mantle dynamic topography or anomalous oceanic crustal thickness. Residual depth anomalies (RDA) corrected for sediment loading, using flexural backstripping and decompaction, have been calculated by comparing observed and age predicted oceanic bathymetries in order to identify anomalous oceanic bathymetry and subsidence at these margins. Age predicted bathymetric anomalies have been calculated using the thermal plate model predictions from Crosby & McKenzie (2009). Non-zero sediment corrected RDAs may result from anomalous oceanic crustal thickness with respect to the global average, or from mantle dynamic uplift. Positive RDAs may result from thicker than average oceanic crust or mantle dynamic uplift; negative RDAs may result from thinner than average oceanic crust or mantle dynamic subsidence. Gravity inversion incorporating a lithosphere thermal gravity anomaly correction and sediment thickness from 2D seismic data has been used to determine Moho depth and oceanic crustal basement thickness. The reference Moho depths used in the gravity inversion have been calibrated against seismic refraction Moho depths. The gravity inversion crustal basement thicknesses

  18. ttH anomalous coupling in double Higgs production

    International Nuclear Information System (INIS)

    We study the effects of top-Higgs anomalous coupling in the production of a pair of Higgs boson via gluon fusion at the Large Hadron Collider (LHC). The introduction of anomalous ttH coupling can alter the hadronic double Higgs boson cross section and can lead to characteristic changes in certain kinematic distributions. We perform a global analysis based on available LHC data on the Higgs to constrain the parameters of ttH anomalous coupling. Possible overlap of the predictions due to anomalous ttH coupling with those due to anomalous trilinear Higgs coupling is also studied. We briefly discuss the effect of the anomalous ttH coupling on the HZ production via gluon fusion which is one of the main backgrounds in the HH→γγbb-macron channel

  19. Scaling theory for anomalous semiclassical quantum transport

    International Nuclear Information System (INIS)

    Quantum transport through devices coupled to electron reservoirs can be described in terms of the full counting statistics (FCS) of charge transfer. Transport observables, such as conductance and shot-noise power are just cumulants of FCS and can be obtained from the sample’s average density of transmission eigenvalues, which in turn can be obtained from a finite element representation of the saddle-point equation of the Keldysh (or supersymmetric) nonlinear sigma model, known as quantum circuit theory. Normal universal metallic behavior in the semiclassical regime is controlled by the presence of a Fabry–Pérot singularity in the average density of transmission eigenvalues. We present general conditions for the suppression of Fabry–Pérot modes in the semiclassical regime in a sample of arbitrary shape, a disordered conductor or a network of ballistic quantum dots, which leads to an anomalous metallic phase. Through a double-scaling limit, we derive a scaling equation for anomalous metallic transport, in the form of a nonlinear differential equation, which generalizes the ballistic-diffusive scaling equation of a normal metal. The two-parameter stationary solution of our scaling equation generalizes Dorokhov’s universal single-parameter distribution of transmission eigenvalues. We provide a simple interpretation of the stationary solution using a thermodynamic analogy with a spin-glass system. As an application, we consider a system formed by a diffusive wire coupled via a barrier to normal-superconductor reservoirs. We observe anomalous reflectionless tunneling, when all perfectly transmitting channels are suppressed, which cannot be explained by the usual mechanism of disorder-induced opening of tunneling channels. (paper)

  20. Scaling theory for anomalous semiclassical quantum transport

    Science.gov (United States)

    Sena-Junior, M. I.; Macêdo, A. M. S.

    2016-01-01

    Quantum transport through devices coupled to electron reservoirs can be described in terms of the full counting statistics (FCS) of charge transfer. Transport observables, such as conductance and shot-noise power are just cumulants of FCS and can be obtained from the sample's average density of transmission eigenvalues, which in turn can be obtained from a finite element representation of the saddle-point equation of the Keldysh (or supersymmetric) nonlinear sigma model, known as quantum circuit theory. Normal universal metallic behavior in the semiclassical regime is controlled by the presence of a Fabry-Pérot singularity in the average density of transmission eigenvalues. We present general conditions for the suppression of Fabry-Pérot modes in the semiclassical regime in a sample of arbitrary shape, a disordered conductor or a network of ballistic quantum dots, which leads to an anomalous metallic phase. Through a double-scaling limit, we derive a scaling equation for anomalous metallic transport, in the form of a nonlinear differential equation, which generalizes the ballistic-diffusive scaling equation of a normal metal. The two-parameter stationary solution of our scaling equation generalizes Dorokhov's universal single-parameter distribution of transmission eigenvalues. We provide a simple interpretation of the stationary solution using a thermodynamic analogy with a spin-glass system. As an application, we consider a system formed by a diffusive wire coupled via a barrier to normal-superconductor reservoirs. We observe anomalous reflectionless tunneling, when all perfectly transmitting channels are suppressed, which cannot be explained by the usual mechanism of disorder-induced opening of tunneling channels.

  1. Can Gravitational Waves Prevent Inflation?

    CERN Document Server

    Shinkai, H; SHINKAI, Hisa-aki; MAEDA, Kei-ichi

    1993-01-01

    To investigate the cosmic no hair conjecture, we analyze numerically 1-dimensional plane symmetrical inhomogeneities due to gravitational waves in vacuum spacetimes with a positive cosmological constant. Assuming periodic gravitational pulse waves initially, we study the time evolution of those waves and the nature of their collisions. As measures of inhomogeneity on each hypersurface, we use the 3-dimensional Riemann invariant ${\\cal I}\\equiv {}~^{(3)\\!}R_{ijkl}~^{(3)\\!}R^{ijkl}$ and the electric and magnetic parts of the Weyl tensor. We find a temporal growth of the curvature in the waves' collision region, but the overall expansion of the universe later overcomes this effect. No singularity appears and the result is a ``no hair" de Sitter spacetime. The waves we study have amplitudes between $0.020\\Lambda \\leq {\\cal I}^{1/2} \\leq 125.0\\Lambda$ and widths between $0.080l_H \\leq l \\leq 2.5l_H$, where $l_H=(\\Lambda/3)^{-1/2}$, the horizon scale of de Sitter spacetime. This supports the cosmic no hair conjectu...

  2. Probing a Gravitational Cat State

    CERN Document Server

    Anastopoulos, Charis

    2015-01-01

    We investigate the nature of a gravitational two-state system (G2S) in the simplest setup in Newtonian gravity. In a quantum description of matter a single motionless massive particle can in principle be in a superposition state of two spatially-separated locations. This superposition state in gravity, or gravitational cat state, would lead to fluctuations in the Newtonian force exerted on a nearby test particle. The central quantity of importance for this inquiry is the energy density correlation. This corresponds to the noise kernel in stochastic gravity theory, evaluated in the weak field nonrelativistic limit. In this limit, quantum fluctuations of the stress energy tensor manifest as the fluctuations of the Newtonian force. We describe the properties of such a G2S system and present two ways of measuring the cat state for the Newtonian force, one by way of a classical probe, the other a quantum harmonic oscillator. Our findings include: (i) mass density fluctuations persist even in single particle system...

  3. Gravitational-wave Mission Study

    Science.gov (United States)

    Mcnamara, Paul; Jennrich, Oliver; Stebbins, Robin T.

    2014-01-01

    In November 2013, ESA selected the science theme, the "Gravitational Universe," for its third large mission opportunity, known as L3, under its Cosmic Vision Programme. The planned launch date is 2034. ESA is considering a 20% participation by an international partner, and NASA's Astrophysics Division has indicated an interest in participating. We have studied the design consequences of a NASA contribution, evaluated the science benefits and identified the technology requirements for hardware that could be delivered by NASA. The European community proposed a strawman mission concept, called eLISA, having two measurement arms, derived from the well studied LISA (Laser Interferometer Space Antenna) concept. The US community is promoting a mission concept known as SGO Mid (Space-based Gravitational-wave Observatory Mid-sized), a three arm LISA-like concept. If NASA were to partner with ESA, the eLISA concept could be transformed to SGO Mid by the addition of a third arm, augmenting science, reducing risk and reducing non-recurring engineering costs. The characteristics of the mission concepts and the relative science performance of eLISA, SGO Mid and LISA are described. Note that all results are based on models, methods and assumptions used in NASA studies

  4. Relativity in Combinatorial Gravitational Fields

    Directory of Open Access Journals (Sweden)

    Mao Linfan

    2010-04-01

    Full Text Available A combinatorial spacetime $(mathscr{C}_G| uboverline{t}$ is a smoothly combinatorial manifold $mathscr{C}$ underlying a graph $G$ evolving on a time vector $overline{t}$. As we known, Einstein's general relativity is suitable for use only in one spacetime. What is its disguise in a combinatorial spacetime? Applying combinatorial Riemannian geometry enables us to present a combinatorial spacetime model for the Universe and suggest a generalized Einstein gravitational equation in such model. Forfinding its solutions, a generalized relativity principle, called projective principle is proposed, i.e., a physics law ina combinatorial spacetime is invariant under a projection on its a subspace and then a spherically symmetric multi-solutions ofgeneralized Einstein gravitational equations in vacuum or charged body are found. We also consider the geometrical structure in such solutions with physical formations, and conclude that an ultimate theory for the Universe maybe established if all such spacetimes in ${f R}^3$. Otherwise, our theory is only an approximate theory and endless forever.

  5. Gravitation as a gauge theory

    International Nuclear Information System (INIS)

    We present gauge theories of gravitation based, respectively, on the general linear group GL(n, R) and its inhomogeneous extension IGL(n, R). [SO(n-1,1) and ISO(n-1,1) for torsion-free manifolds]. Noting that the geometry of the conventional gauge theories can be described in terms of a principal fiber bundle, and that their action is a scalar in such a superspace, we construct principal fiber bundles based on the above gauge groups and propose to describe gravitation in terms of their corresponding scalar curvatures. To ensure that these manifolds do indeed have close ties with the space-time of general relativity, we make use of the notion of the parallel transport of vector fields in space-time to uniquely relate the connections in space-time to the gauge potentials in fiber bundles. The relations turn out to be similar to that suggested earlier by Yang. The actions we obtain are related to those of Einstein and Yang but are distinct from both and have an Einstein limit. The inclusion of internal symmetry leads to the analogs of Einstein-Yang-Mills equations. A number of variations and less attractive alternatives based on the subgroups of the above groups are also discussed

  6. Localization corrections to the anomalous Hall effect in a ferromagnet

    OpenAIRE

    Dugaev, V. K.; Crepieux, A.; Bruno, P

    2001-01-01

    We calculate the localization corrections to the anomalous Hall conductivity related to the contribution of spin-orbit scattering into the current vertex (side-jump mechanism). We show that in contrast to the ordinary Hall effect, there exists a nonvanishing localization correction to the anomalous Hall resistivity. The correction to the anomalous Hall conductivity vanishes in the case of side-jump mechanism, but is nonzero for the skew scattering. The total correction to the nondiagonal cond...

  7. Anomalous Josephson Hall effect in magnet/triplet superconductor junctions

    OpenAIRE

    Yokoyama, Takehito

    2015-01-01

    We investigate anomalous Hall effect in a magnet coupled to a triplet superconductor under phase gradient. It is found that the anomalous Hall supercurrent arises from non-trivial structure of the magnetization. The magnetic structure manifested in the Hall supercurrent is characterized by even order terms of the exchange coupling, essentially different from that discussed in the context of anomalous Hall effect, reflecting the disspationless nature of supercurrent. We also discuss a possible...

  8. Anomalous Hall effect in YIG$|$Pt bilayers

    OpenAIRE

    Meyer, Sibylle; Schlitz, Richard; Geprägs, Stephan; Opel, Matthias; Huebl, Hans; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2015-01-01

    We measure the ordinary and the anomalous Hall effect in a set of yttrium iron garnet$|$platinum (YIG$|$Pt) bilayers via magnetization orientation dependent magnetoresistance experiments. Our data show that the presence of the ferrimagnetic insulator YIG leads to an anomalous Hall like signature in Pt, sensitive to both Pt thickness and temperature. Interpretation of the experimental findings in terms of the spin Hall anomalous Hall effect indicates that the imaginary part of the spin mixing ...

  9. Anomalous x-ray radiation of beam plasma

    International Nuclear Information System (INIS)

    The properties of non-equilibrium stationary plasma under the conditions of the planned plasma-chemical reactors based on beam-plasma discharge were investigated. The x-ray spectrum of the beam-plasma was measured and anomalous spectral properties were analyzed. Starting with some critical pressure the anomalous radiation was added to the classical bremsstrahlung spectrum. The occurrence of anomalous radiation can be used to diagnose the condition of beam transportation in such systems. (D.Gy.)

  10. Anomalous magnetoresistance on the topological surface

    International Nuclear Information System (INIS)

    We report theoretical study of charge transport in two-dimensional ferromag-net/ferromagnet junction on a topological insulator. The conductance across the interface shows anomalous dependence on the directions of the magnetizations of the two ferromagnets. This stems from the way how the wavefunctions connect between both sides. It is found that the conductance depends strongly on the in-plane direction of the magnetization. Moreover, in stark contrast to the conventional magnetoresistance effect, the conductance at the parallel configuration can be much smaller than that at the antiparallel configuration.

  11. Study of the anomalous ionization phenomenum

    International Nuclear Information System (INIS)

    Results of experiments at the ''IKI large barometric chamber'' (Moscow) and the ''SOMB'' Sib ISMIR (Irkutsk) facilities are stated. It is shown that the presence of magnetic field H perpendicular U1 during relative motion of plasma and gas stream at U1 > Usub(ca) velocity (Usub(ca)-critical velocity of ionization) leads to anomalous gas ionization on Lsub(x) scale, where Psub(e) 2 long H-fsub(e)(νsub(z)) turns out to be significantly non-equilibrium at Vsub(Z) > Vsub(Te) √ 2Te/m

  12. Anomalous mapping between pionfull and pionless EFT's

    OpenAIRE

    Yang, J. -F.

    2013-01-01

    The pion contributions to the coupling $C_0$ of pionless EFT are studied via both non-relativistic and relativistic forms of chiral effective field theory for nuclear forces. A definite item in the $2N$-reducible component of the box diagram is shown to be dominant over the $2N$-irreducible (potential) ones due to the pinching of low-lying nucleon poles, and this anomalous mapping between pionless and pionfull EFT's occurs right within the non-relativistic regime. A natural strategy for renor...

  13. Anomalous Diffusion on the Hanoi Networks

    OpenAIRE

    Boettcher, S.; B. Goncalves

    2008-01-01

    Diffusion is modeled on the recently proposed Hanoi networks by studying the mean- square displacement of random walks with time, ~t^{2/d_w}. It is found that diffusion - the quintessential mode of transport throughout Nature - proceeds faster than ordinary, in one case with an exact, anomalous exponent dw = 2-log_2(\\phi) = 1.30576 . . .. It is an instance of a physical exponent containing the "golden ratio" \\phi=(1+\\sqrt{5})/2 that is intimately related to Fibonacci sequences and since Eucli...

  14. HR 4453 - An anomalously bright UV source

    Science.gov (United States)

    Polidan, R. S.; Oegerle, W. R.; Margon, B.

    1980-01-01

    Crawford et al. (1979) reported that HR 4453 has an anomalously large UV flux in the 1350-1600 A band. This paper reports results of the UV spectrophotometry of HR 4453 obtained with the Copernicus satellite. Portions of the spectrum from 1120 to 2660 A were scanned, but no stellar signal was detected in any wavelength interval. This result is consistent with both components of the binary being normal A2A stars. UV variability or a source other than HR 4453 must be invoked to explain the observations of Crawford et al.

  15. On the photon anomalous magnetic moment

    CERN Document Server

    Villalba, S; Villalba, Selym; Rojas, Hugo Perez

    2006-01-01

    It is shown that due to radiative corrections a photon having a non vanishing component of its momentum perpendicular to it, bears a non-zero magnetic moment. All modes of propagation of the polarization operator in one loop approximation are discussed and in this field regime the dispersion equation and the corresponding magnetic moment are derived. Near the first thresholds of cyclotron resonance the photon magnetic moment has a peak larger than the electron anomalous magnetic moment. Related to this magnetic moment, the arising of some sort of photon "dynamical mass" and a gyromagnetic ratio are discussed. These latter results might be interesting in an astrophysical context.

  16. Anomalous Cepheid period-luminosity relationships

    International Nuclear Information System (INIS)

    The P-L relationship for anomalous Cepheids (ACs) splits into two well-defined lines in the log P - M(B) plane. One line corresponds to pulsation in the fundamental mode, and the other corresponds to the first-overtone. If these P-L relationships are universal, then they can be used to estimate distances to nearby dwarf galaxies. Knowledge of pulsation modes of the ACs in Draco suggests a mass range of 1.04 to 1.7 solar mass

  17. Anomalous Redshift of Some Galactic Objects

    CERN Document Server

    Zheng, Yi-Jia

    2013-01-01

    Anomalous redshifts of some galactic objects such as binary stars, early-type stars in the solar neighborhood, and O stars in a star clusters are discussed. It is shown that all these phenomena have a common characteristic, that is, the redshifts of stars increase as the temperature rises. This characteristic cannot be explained by means of the Doppler Effect but can by means of the soft-photon process proposed by Yijia Zheng (arXiv:1305.0427 [astro-ph.HE]).

  18. Gravitational collapse of spherically symmetric stars in noncommutative general relativity

    International Nuclear Information System (INIS)

    Gravitational collapse of a class of spherically symmetric stars is investigated. We quantise the geometries describing the gravitational collapse by a deformation quantisation procedure. This gives rise to noncommutative spacetimes with gravitational collapse. (orig.)

  19. A report on the gravitational redshift test for non-metric theories of gravitation

    Science.gov (United States)

    1980-01-01

    The frequencies of two atomic hydrogen masers and of three superconducting cavity stabilized oscillators were compared as the ensemble of oscillators was moved in the Sun's gravitational field by the rotation and orbital motion of the Earth. Metric gravitation theories predict that the gravitational redshifts of the two types of oscillators are identical, and that there should be no relative frequency shift between the oscillators; nonmetric theories, in contrast, predict a frequency shift between masers and SCSOs that is proportional to the change in solar gravitational potential experienced by the oscillators. The results are consistent with metric theories of gravitation at a level of 2%.

  20. Testing Gravitational Physics with Space-based Gravitational-wave Observations

    Science.gov (United States)

    Baker, John G.

    2011-01-01

    Gravitational wave observations provide exceptional and unique opportunities for precision tests of gravitational physics, as predicted by general relativity (GR). Space-based gravitational wave measurements, with high signal-to-noise ratios and large numbers of observed events may provide the best-suited gravitational-wave observations for testing GR with unprecedented precision. These observations will be especially useful in testing the properties of gravitational waves and strong-field aspects of the theory which are less relevant in other observations. We review the proposed GR test based on observations of massive black hole mergers, extreme mass ratio inspirals, and galactic binary systems.

  1. Anomalous transport effects in magnetically-confined plasma columns

    International Nuclear Information System (INIS)

    The evolution of density structure in a magnetized plasma column is analyzed accounting for anomalous diffusion due to the lower hybrid drift instability. The plasma column is found to be divided into regions of classical, anomalous, and intermediate diffusivity. The bulk behavior, described in terms of radial confinement time, depends most sensitively upon the particle line density (ion/cm). For broad plasmas (large line density), the transport is characteristic of classical diffusion, and for slender plasmas (small line density) the transport is characteristic of anomalous diffusion. For intermediate line densities, the transport undertakes a rapid transition from classical to anomalous. Correlations between the theoretical results and past experiments are described

  2. Anomalous WWZ couplings and KL → μ+ μ-

    International Nuclear Information System (INIS)

    The author analysed contributions to KL → μ+μ- from anomalous WWZ interactions. There are, in general, seven anomalous couplings. Among the seven anomalous couplings, only two of them contribute significantly. The others are suppressed by factors like m2s/M2W, m2d/M2W, or M2K/M2W. Using the experimental data on KL → μ+μ-, it is possible to obtain strong bounds on the two anomalous couplings. 10 refs., 6 tabs

  3. A low temperature gravitational radiation detector

    Science.gov (United States)

    Hamilton, W. O.

    1971-01-01

    The beginning design of an experiment is discussed for studying gravitational radiation by using massive detectors which are cooled to ultralow temperatures in order to improve the signal to noise ratios and the effective range and stability of the detectors. The gravitational detector, a low detection system, a cooled detector, magnetic support, superconducting shielding, and superconducting accelerometer detector are described.

  4. Articulated Multimedia Physics, Lesson 9, Universal Gravitation.

    Science.gov (United States)

    New York Inst. of Tech., Old Westbury.

    As the ninth lesson of the Articulated Multimedia Physics Course, instructional materials relating to universal gravitation are presented in this study guide. The subject is concerned with the quantitative meaning of the law of universal gravitation and its applications in astronomy. The content is arranged in scrambled form, and the use of matrix…

  5. Gravitational waves from accreting neutron stars

    OpenAIRE

    Bonazzola, S.; Gourgoulhon, E.

    1996-01-01

    We show that accreting neutron stars in binary systems or in Landau-Thorne-Zytkow objects are good candidates for continuous gravitational wave emission. Their gravitational radiation is strong enough to be detected by the next generation of detectors having a typical noise of 10^{-23} Hz^{-1/2}.

  6. Interaction of light with gravitational waves

    OpenAIRE

    2013-01-01

    The physical properties of electromagnetic waves in the presence of a gravitational plane wave are analyzed. Formulas for the Stokes parameters describing the polarization of light are obtained in closed form. The particular case of a constant amplitude gravitational wave is worked out explicitly.

  7. Accelerating the Universe with Gravitational Waves

    OpenAIRE

    Brown, I A; Schrempp, L.; Ananda, K

    2009-01-01

    Inflation generically produces primordial gravitational waves with a red spectral tilt. In this paper we calculate the backreaction produced by these gravitational waves on the expansion of the universe. We find that in radiation domination the backreaction acts as a relativistic fluid, while in matter domination a small dark energy emerges with an equation of state w=-8/9.

  8. Nonlinear gravitational waves and their polarization

    OpenAIRE

    Canfora, F.; Vilasi, G.; Vitale, P.

    2002-01-01

    Vacuum gravitational fields invariant for a non Abelian Lie algebra generated by two Killing fields whose commutator is light-like are analyzed. It is shown that they represent nonlinear gravitational waves obeying to two nonlinear superposition laws. The energy and the polarization of this family of waves are explicitely evaluated.

  9. On high energy scattering inside gravitational backgrounds

    OpenAIRE

    Nastase, Horatiu

    2004-01-01

    We analyze the high energy scattering inside gravitational backgrounds using 't Hooft's formalism. The scattering is equivalent to geodesic shifts accross Aichelburg-Sexl waves inside the gravitational backgrounds. We find solutions for A-S waves inside various backgrounds and analyze them.

  10. Spin Angular Momentum Imparted by Gravitational Waves

    OpenAIRE

    Sharif, M.

    2007-01-01

    Following the demonstration that gravitational waves impart linear momentum, it is argued that if they are polarized they should impart angular momentum to appropriately placed 'test rods' in their path. A general formula for this angular momentum is obtained and used to provide expressions for the angular momentum imparted by plane and cylindrical gravitational waves.

  11. Quantized gravitational waves in the Milne universe

    OpenAIRE

    Tanaka, Takahiro; Sasaki, Misao

    1996-01-01

    The quantization of gravitational waves in the Milne universe is discussed. The relation between positive frequency functions of the gravitational waves in the Milne universe and those in the Minkowski universe is clarified. Implications to the one-bubble open inflation scenario are also discussed.

  12. Gravitational Collapse of Prolate Brill Waves

    OpenAIRE

    Rinne, Oliver

    2009-01-01

    It has been conjectured that the gravitational collapse of sufficiently prolate vacuum axisymmetric gravitational waves (Brill waves) may violate cosmic censorship. Improving on earlier work by Garfinkle and Duncan, I present a numerical evolution of such a prolate initial data set that does form an apparent horizon. Related advances in the construction of axisymmetric constrained evolution schemes are also discussed.

  13. Gravitational waves with torsion in 3D

    OpenAIRE

    Blagojević, M.; Cvetković, B.

    2014-01-01

    We study gravitational waves with torsion as exact vacuum solutions of three-dimensional gravity with propagating torsion. The new solutions are a natural generalization of the plane-fronted gravitational waves in general relativity with a cosmological constant, in the presence of matter.

  14. Gravitational deflection of light and helicity asymmetry

    OpenAIRE

    Guadagnini, Enore

    2002-01-01

    The helicity modification of light polarization which is induced by the gravitational deflection from a classical heavy rotating body, like a star or a planet, is considered. The expression of the helicity asymmetry is derived; this asymmetry signals the gravitationally induced spin transfer from the rotating body to the scattered photons.

  15. Gravitational Wave Background from Phantom Superinflation

    OpenAIRE

    Piao, Yun-Song

    2006-01-01

    Recently, the early superinflation driven by phantom field has been proposed and studied. The detection of primordial gravitational wave is an important means to know the state of very early universe. In this brief report we discuss in detail the gravitational wave background excited during the phantom superinflation.

  16. GRAVITATIONAL EXPERIMENTS WITH STABLE ELECTROMAGNETIC DEVICES

    OpenAIRE

    Tourrenc, Ph.

    1981-01-01

    This article presents a general method for studying the effect of a gravitational field on the phases of an electromagnetic wave. The method employed covers a broad range of experiments within the limited framework of PPN theories to pick out orders of magnitude concerning the different kinds of experiments which may be performed on earth with astronomical sources of gravitation.

  17. Observation of Gravitational Waves in Advanced LIGO

    Science.gov (United States)

    Cadonati, Laura

    2016-04-01

    One hundred years after Einstein's formulation of General Relativity, LIGO has observed gravitational waves from a binary black hole merger. In this talk I will present this groundbreaking discovery, which took place during the first observing run of Advanced LIGO, and its implications for a new gravitational wave astronomy.

  18. Quantized gravitational waves in the Milne universe

    CERN Document Server

    Tanaka, T; Tanaka, Takahiro; Sasaki, Misao

    1997-01-01

    The quantization of gravitational waves in the Milne universe is discussed. The relation between positive frequency functions of the gravitational waves in the Milne universe and those in the Minkowski universe is clarified. Implications to the one-bubble open inflation scenario are also discussed.

  19. Axially symmetric SU(3) gravitating skyrmions

    Energy Technology Data Exchange (ETDEWEB)

    Ioannidou, Theodora [Maths Division, School of Technology, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)]. E-mail: ti3@auth.gr; Kleihaus, Burkhard [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany)]. E-mail: kleihaus@theorie.physik.uni-oldenburg.de; Zakrzewski, Wojtek [Department of Mathematical Sciences, University of Durham, Durham DH1 3LE (United Kingdom)]. E-mail: w.j.zakrzewski@durham.ac.uk

    2004-10-21

    Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [J. Math. Phys. 40 (1999) 6353]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail.

  20. Axially symmetric SU(3) Gravitating Skyrmions

    CERN Document Server

    Ioannidou, T A; Zakrzewski, W J; Ioannidou, Theodora; Kleihaus, Burkhard; Zakrzewski, Wojtek

    2004-01-01

    Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [1]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail.

  1. Axially symmetric SU(3) gravitating skyrmions

    International Nuclear Information System (INIS)

    Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [J. Math. Phys. 40 (1999) 6353]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail

  2. Inertial reference frames and gravitational forces

    International Nuclear Information System (INIS)

    The connection between different definitions of inertial, i.e. fundamental, reference frames and the corresponding characterisation of gravitational fields by gravitational forces are considered from the point of view of their possible interpretation in university introductory courses. The introduction of a special class of reference frames, denoted 'mixed reference frames' is proposed and discussed. (author)

  3. Self-gravitation in Saturn's rings

    International Nuclear Information System (INIS)

    In a ring-shaped collisional system self-gravitation reduces the equilibrium values of the geometric and optical thickness. In Saturn's rings both effects are appreciable. The previously found discrepancy between the calculated profile and the observed profile of the rings is chiefly caused by the omission of self-gravitation. (Auth.)

  4. Workshop on gravitational waves and relativistic astrophysics

    Indian Academy of Sciences (India)

    Patrick Das Gupta

    2004-10-01

    Discussions related to gravitational wave experiments viz. LIGO and LISA as well as to observations of supermassive black holes dominated the workshop sessions on gravitational waves and relativistic astrophysics in the ICGC-2004. A summary of seven papers that were presented in these workshop sessions has been provided in this article.

  5. A distinguishing gravitational property for gravitational equation in higher dimensions

    International Nuclear Information System (INIS)

    It is well known that Einstein gravity is kinematic (meaning that there is no non-trivial vacuum solution; i.e. the Riemann tensor vanishes whenever the Ricci tensor does so) in 3 dimension because the Riemann tensor is entirely given in terms of the Ricci tensor. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one Nth order term in the action) gravity for which the Nth order Lovelock-Riemann tensor is indeed given in terms of the corresponding Ricci tensor for all odd, d = 2N + 1, dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good distinguishing and guiding criterion for the gravitational equation in higher dimensions. (orig.)

  6. A discerning gravitational property for gravitational equation in higher dimensions

    CERN Document Server

    Dadhich, Naresh

    2015-01-01

    It is well-known that Einstein gravity is kinematic (no non-trivial vacuum solution;i.e. Riemann vanishes whenever Ricci does so) in $3$ dimension because Riemann is entirely given in terms of Ricci. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one $N$th order term in action) gravity for which $N$th order Lovelock Riemann tensor is indeed given in terms of corresponding Ricci for all odd $d=2N+1$ dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good discerning and guiding criterion for gravitational equation in higher dimensions.

  7. A distinguishing gravitational property for gravitational equation in higher dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Dadhich, Naresh [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Pune (India)

    2016-03-15

    It is well known that Einstein gravity is kinematic (meaning that there is no non-trivial vacuum solution; i.e. the Riemann tensor vanishes whenever the Ricci tensor does so) in 3 dimension because the Riemann tensor is entirely given in terms of the Ricci tensor. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one Nth order term in the action) gravity for which the Nth order Lovelock-Riemann tensor is indeed given in terms of the corresponding Ricci tensor for all odd, d = 2N + 1, dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good distinguishing and guiding criterion for the gravitational equation in higher dimensions. (orig.)

  8. Probing Cosmic Superstrings with Gravitational Waves

    CERN Document Server

    Sousa, Lara

    2016-01-01

    We compute the stochastic gravitational wave background generated by cosmic superstrings using a semi-analytical velocity-dependent model to describe their dynamics. We show that heavier string types may leave distinctive signatures on the stochastic gravitational wave background spectrum within the reach of present and upcoming gravitational wave detectors. We examine the physically motivated scenario in which the physical size of loops is determined by the gravitational backreaction scale and use NANOGRAV data to derive a conservative constraint of $G\\mu_F<3.2 \\times 10^{-9}$ on the tension of fundamental strings. We demonstrate that approximating the gravitational wave spectrum generated by cosmic superstring networks using the spectrum generated by ordinary cosmic strings with reduced intercommuting probability (which is often done in the literature) leads, in general, to weaker observational constraints on $G\\mu_F$. We show that the inclusion of heavier string types is required for a more accurate cha...

  9. Comparing numerical and analytic approximate gravitational waveforms

    Science.gov (United States)

    Afshari, Nousha; Lovelace, Geoffrey; SXS Collaboration

    2016-03-01

    A direct observation of gravitational waves will test Einstein's theory of general relativity under the most extreme conditions. The Laser Interferometer Gravitational-Wave Observatory, or LIGO, began searching for gravitational waves in September 2015 with three times the sensitivity of initial LIGO. To help Advanced LIGO detect as many gravitational waves as possible, a major research effort is underway to accurately predict the expected waves. In this poster, I will explore how the gravitational waveform produced by a long binary-black-hole inspiral, merger, and ringdown is affected by how fast the larger black hole spins. In particular, I will present results from simulations of merging black holes, completed using the Spectral Einstein Code (black-holes.org/SpEC.html), including some new, long simulations designed to mimic black hole-neutron star mergers. I will present comparisons of the numerical waveforms with analytic approximations.

  10. Gravitational Waves in G4v

    CERN Document Server

    Mead, Carver

    2015-01-01

    Gravitational coupling of the propagation four-vectors of matter wave functions is formulated in flat space-time. Coupling at the momentum level rather than at the "force-law" level greatly simplifies many calculations. This locally Lorentz-invariant approach (G4v) treats electromagnetic and gravitational coupling on an equal footing. Classical mechanics emerges from the incoherent aggregation of matter wave functions. The theory reproduces, to first order beyond Newton, the standard GR results for Gravity-Probe B, deflection of light by massive bodies, precession of orbits, gravitational red shift, and total gravitational-wave energy radiated by a circular binary system. Its predictions of total radiated energy from highly eccentric Kepler systems are slightly larger than those of similar GR treatments. G4v predictions differ markedly from those of GR for the gravitational-wave radiation patterns from rotating massive systems, and for the LIGO antenna pattern. The predicted antenna patterns have been shown t...

  11. Gravitational polarization and the phenomenology of MOND

    International Nuclear Information System (INIS)

    The modified Newtonian dynamics (MOND) has been proposed as an alternative to the dark matter paradigm; the philosophy behind is that there is no dark matter and we witness a violation of the Newtonian law of dynamics. In this paper, we interpret the phenomenology sustaining MOND differently, as resulting from an effect of 'gravitational polarization', of some cosmic fluid made of dipole moments, aligned in the gravitational field, and representing a new form of dark matter. We invoke an internal force, of non-gravitational origin, in order to hold together the microscopic constituents of the dipole. The dipolar particles are weakly influenced by the distribution of ordinary matter; they are accelerated not by the gravitational field, but by its gradient or tidal gravitational field

  12. Probing inflation models with gravitational waves

    CERN Document Server

    Domcke, Valerie

    2016-01-01

    A direct detection of primordial gravitational waves is the ultimate probe for any inflation model. While current CMB bounds predict the generic scale-invariant gravitational wave spectrum from slow-roll inflation to be below the reach of upcoming gravitational wave interferometers, this prospect may dramatically change if the inflaton is a pseudoscalar. In this case, a coupling to any abelian gauge field leads to a tachyonic instability for the latter and hence to a new source of gravitational waves, directly related to the dynamics of inflation. In this contribution we discuss how this setup enables the upcoming gravitational wave interferometers advanced LIGO/VIRGO and eLISA to probe the microphysics of inflation, distinguishing between different universality classes of single-field slow-roll inflation models. We find that the prime candidate for an early detection is a Starobinsky-like model.

  13. Local gravitational redshifts can bias cosmological measurements

    CERN Document Server

    Wojtak, Radoslaw; Wiis, Jophiel

    2015-01-01

    Measurements of cosmological parameters via the distance-redshift relation usually rely on models that assume a homogenous universe. It is commonly presumed that the large-scale structure evident in our Universe has a negligible impact on the measurement if distances probed in observations are sufficiently large (compared to the scale of inhomogeneities) and are averaged over different directions on the sky. This presumption does not hold when considering the effect of the gravitational redshift caused by our local gravitational potential, which alters light coming from all distances and directions in the same way. Despite its small magnitude, this local gravitational redshift gives rise to noticeable effects in cosmological inference using SN Ia data. Assuming conservative prior knowledge of the local potential given by sampling a range of gravitational potentials at locations of Milky-Way-like galaxies identified in cosmological simulations, we show that ignoring the gravitational redshift effect in a stand...

  14. Gravitational Interactions and Fine-Structure Constant

    CERN Document Server

    Jentschura, U D; Nandori, I

    2015-01-01

    Electromagnetic and gravitational central-field problems are studied with relativistic quantum mechanics on curved space-time backgrounds. Corrections to the transition current are identified. Analogies of the gravitational and electromagnetic spectra suggest the definition of a gravitational fine-structure constant. The electromagnetic and gravitational coupling constants enter the Einstein-Hilbert-Maxwell Lagrangian. We postulate that the variational principle holds with regard to a global dilation transformation of the space-time coordinates. The variation suggests is consistent with a functional relationship of the form alpha_QED being proportional to alpha_G^(1/2), where alpha_QED is the electrodynamic fine-structure constant, and alpha_G its gravitational analogue.

  15. Anomalous Micellization of Pluronic Block Copolymers

    Science.gov (United States)

    Leonardi, Amanda; Ryu, Chang Y.

    2014-03-01

    Poly(ethylene oxide) - poly(propylene oxide) - poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, commercially known as Pluronics, are a unique family of amphiphilic triblock polymers, which self-assemble into micelles in aqueous solution. These copolymers have shown promise in therapeutic, biomedical, cosmetic, and nanotech applications. As-received samples of Pluronics contain low molecular weight impurities (introduced during the manufacturing and processing), that are ignored in most applications. It has been observed, however, that in semi-dilute aqueous solutions, at concentrations above 1 wt%, the temperature dependent micellization behavior of the Pluronics is altered. Anomalous behavior includes a shift of the critical micellization temperature and formation of large aggregates at intermediate temperatures before stable sized micelles form. We attribute this behavior to the low molecular weight impurities that are inherent to the Pluronics which interfere with the micellization process. Through the use of Dynamic Light Scattering and HPLC, we compared the anomalous behavior of different Pluronics of different impurity levels to their purified counterparts.

  16. More modular invariant anomalous U(1) breaking

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, Mary K.; Giedt, Joel

    2002-06-27

    We consider the case of several scalar fields, charged under a number of U(1) factors, acquiring vacuum expectation values due to anomalous U(1). We demonstrate how to make redefinitions at the superfield level in order to account for tree-level exchange of vector supermultiplets in the effective supergravity theory of the light fields in the supersymmetric vacuum phase. Our approach builds up on previous results that we obtained in a more elementary case. We find that the modular weights of light fields are typically shifted from their original values, allowing an interpretation in terms of the preservation of modular invariance in the effective theory. We address various subtleties in defining unitary gauge that are associated with the noncanonical Kahler potential of modular invariant supergravity, the vacuum degeneracy, and the role of the dilaton field. We discuss the effective superpotential for the light fields and note how proton decay operators may be obtained when the heavy fields are integrated out of the theory at the tree-level. We also address how our formalism may be extended to describe the generalized Green-Schwarz mechanism for multiple anomalous U(1)'s that occur in four-dimensional Type I and Type IIB string constructions.

  17. Macromolecular structure phasing by neutron anomalous diffraction.

    Science.gov (United States)

    Cuypers, Maxime G; Mason, Sax A; Mossou, Estelle; Haertlein, Michael; Forsyth, V Trevor; Mitchell, Edward P

    2016-01-01

    In this report we show for the first time that neutron anomalous dispersion can be used in a practical manner to determine experimental phases of a protein crystal structure, providing a new tool for structural biologists. The approach is demonstrated through the use of a state-of-the-art monochromatic neutron diffractometer at the Institut Laue-Langevin (ILL) in combination with crystals of perdeuterated protein that minimise the level of hydrogen incoherent scattering and enhance the visibility of the anomalous signal. The protein used was rubredoxin in which cadmium replaced the iron at the iron-sulphur site. While this study was carried out using a steady-state neutron beam source, the results will be of major interest for capabilities at existing and emerging spallation neutron sources where time-of-flight instruments provide inherent energy discrimination. In particular this capability may be expected to offer unique opportunities to a rapidly developing structural biology community where there is increasing interest in the identification of protonation states, protein/water interactions and protein-ligand interactions - all of which are of central importance to a wide range of fundamental and applied areas in the biosciences. PMID:27511806

  18. Turbulence: mechanics and structure of anomalous scaling

    Directory of Open Access Journals (Sweden)

    S. N. Gordienko

    2001-01-01

    Full Text Available As the finite correlation time of a force driving turbulence is taken into account, a new, dimensionless parameter occurs in the theory of turbulence. This new parameter is responsible for two different mechanisms of formation of anomalous spectra. The first mechanism is related to the change of a governing parameter, which defines the spectrum of turbulent fluctuation. The second mechanism is associated with spontaneous formation of characteristic scales that differ parametrically from the scale of the external force. The last mechanism can explain the intermittent structure of turbulent flows. The appropriate discrete set of the possible characteristic scales and anomalous spectra has been calculated. The results give a new insight into the concept of universality: there is a set of universal power laws, although occurrence in the spectrum segments described by one or another power law from this set depends on the dimensionless parameter mentioned above. It is noted that for the broad class of geophysical flows, the new dimensionless parameter is connected with the so-called degree of turbulence, which guarantees that the smallness of this parameter, as the degree of turbulence is usually small enough. That explains the important role of the Kolmogorov spectrum in geophysical applications.

  19. Interpretation of the Stephan Quintet Galaxy Cluster using Hydro-Gravitational-Dynamics: Viscosity and Fragmentation

    CERN Document Server

    Gibson, Carl H

    2007-01-01

    Stephan's Quintet (SQ) is a compact group of galaxies that has been well studied since its discovery in 1877 but is mysterious using cold dark matter hierarchical clustering cosmology (CDMHCC). Anomalous red shifts $z = (0.0027,0.019, 0.022, 0.022, 0.022)$ among galaxies in SQ either reduce it to a Trio with two highly improbable intruders from CDMHCC or support the Arp (1973) hypothesis that its red shifts are intrinsic. An alternative is provided by the Gibson 1996-2006 hydro-gravitational-dynamics (HGD) theory where superclusters, clusters and galaxies all originate by gravitational fragmentation in the super-viscous plasma epoch and at planetary and star cluster mass scales in the primordial gas of the expanding universe. By this fluid-mechanical cosmology, the SQ galaxies gently separate and remain precisely along a line of sight because of perspective and the small transverse velocities permitted by their sticky viscous-gravitational beginnings. Star and gas bridges and young-globular-star-cluster (YGC)...

  20. Global gravitational anomalies and transport

    CERN Document Server

    Chowdhury, Subham Dutta

    2016-01-01

    We investigate the constraints imposed by global gravitational anomalies on parity odd induced transport coefficients in even dimensions for theories with chiral fermions, gravitinos and self dual tensors. The $\\eta$-invariant for the large diffeomorphism corresponding to the $T$ transformation on a torus constraints the coefficients in the thermal effective action up to mod 2. We show that the result obtained for the parity odd transport for gravitinos using global anomaly matching is consistent with the direct perturbative calculation. In $d=6$ we see that the second Pontryagin class in the anomaly polynomial does not contribute to the $\\eta$-invariant which provides a topological explanation of this observation in the `replacement rule'. We then perform a direct perturbative calculation for the contribution of the self dual tensor in $d=6$ to the parity odd transport coefficient using the Feynman rules proposed by Gaum\\'{e} and Witten. The result for the transport coefficient agrees with that obtained usin...