Multipole Models of Four-Image Gravitational Lenses with Anomalous Flux Ratios
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...
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-...
Anomalous CMB polarization and gravitational chirality
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.
Anomalous center of mass shift gravitational dipole moment
Jeong, E J
1996-01-01
The anomalous, energy dependent shift of the center of mass of an idealized, perfectly rigid, uniformly rotating hemispherical shell which is caused by the relativistic mass increase effect is investigated in detail. It is shown that a classical object on impact which has the harmonic binding force between the adjacent constituent particles has the similar effect of the energy dependent, anomalous shift of the center of mass. From these observations, the general mode of the linear acceleration is suggested to be caused by the anomalous center of mass shift whether it's due to classical or relativistic origin. The effect of the energy dependent center of mass shift perpendicular to the plane of rotation of a rotating hemisphere appears as the non zero gravitational dipole moment in general relativity. Controlled experiment for the measurement of the gravitational dipole field and its possible links to the cylindrical type line formation of a worm hole in the extreme case are suggested. The jets from the black ...
Anomalous center of mass shift: gravitational dipole moment.
Jeong, Eue Jin
1997-02-01
The anomalous, energy dependent shift of the center of mass of an idealized, perfectly rigid, uniformly rotating hemispherical shell which is caused by the relativistic mass increase effect is investigated in detail. It is shown that a classical object on impact which has the harmonic binding force between the adjacent constituent particles has the similar effect of the energy dependent, anomalous shift of the center of mass. From these observations, the general mode of the linear acceleration is suggested to be caused by the anomalous center of mass shift whether it's due to classical or relativistic origin. The effect of the energy dependent center of mass shift perpendicular to the plane of rotation of a rotating hemisphere appears as the non zero gravitational dipole moment in general relativity. Controlled experiment for the measurement of the gravitational dipole field and its possible links to the cylindrical type line formation of a worm hole in the extreme case are suggested. The jets from the black hole accretion disc and the observed anomalous red shift from far away galaxies are considered to be the consequences of the two different aspects of the dipole gravity.
Anomalous effects due to the inertial anti-gravitational potential of the sun
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...
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...
Anomalous Polarization-Curvature Interaction in a Gravitational-Wave Field
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.
Using Spectral Flux Ratios to Standardize SN Ia Luminosities
Bailey, S; Antilogus, P; Aragon, C; Baltay, C; Bongard, S; Buton, C; Childress, M; Chotard, N; Copin, Y; Gangler, E; Loken, S; Nugent, P; Pain, R; Pécontal, E; Pereira, R; Perlmutter, S; Rabinowitz, D; Rigaudier, G; Runge, K; Scalzo, R; Smadja, G; Swift, H; Tao, C; Thomas, R C; Wu, C
2009-01-01
We present a new method to standardize Type Ia supernova (SN Ia) luminosities to ~<0.13 magnitudes using flux ratios from a single flux-calibrated spectrum per SN. Using Nearby Supernova Factory spectrophotomery of 58 SNe Ia, we performed an unbiased search for flux ratios which correlate with SN Ia luminosity. After developing the method and selecting the best ratios from a training sample, we verified the results on a separate validation sample and with data from the literature. We identified multiple flux ratios whose correlations with luminosity are stronger than those of light curve shape and color, previously identified spectral feature ratios, or equivalent width measurements. In particular, the flux ratio R(642/443) = F(642 nm) / F(443 nm) has a correlation of 0.95 with SN Ia absolute magnitudes. Using this single ratio as a correction factor produces a Hubble diagram with a residual scatter standard deviation of 0.125 +- 0.011 mag, compared with 0.161 +- 0.015 mag when fit with the SALT2 light cur...
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.
Fitting Gravitational Lenses Truth or Delusion
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...
Gravitational Encounters and the Evolution of Galactic Nuclei. III. Anomalous Relaxation
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...
Hsueh, J.-W.; Fassnacht, C. D.; Vegetti, S.; McKean, J. P.; Spingola, C.; Auger, M. W.; Koopmans, L. V. E.; Lagattuta, D. J.
2016-11-01
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 that 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-ratio anomalies are due to a population of dark matter sub-haloes may be incorrect, and analyses that do not account for the full complexity of the lens macro-model may overestimate the substructure mass fraction in massive lensing galaxies.
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 ?
Effect of OH depletion on measurements of the mass-to-flux ratio in molecular cloud cores
Tassis, K; Yorke, H W; Turner, N J
2014-01-01
The ratio of mass and magnetic flux determines the relative importance of magnetic and gravitational forces in the evolution of molecular clouds and their cores. Its measurement is thus central in discriminating between different theories of core formation and evolution. Here we discuss the effect of chemical depletion on measurements of the mass-to-flux ratio using the same molecule (OH) both for Zeeman measurements of the magnetic field and the determination of the mass of the region. The uncertainties entering through the OH abundance in determining separately the magnetic field and the mass of a region have been recognized in the literature. It has been proposed however that, when comparing two regions of the same cloud, the abundance will in both cases be the same. We show that this assumption is invalid. We demonstrate that when comparing regions with different densities, the effect of OH depletion in measuring changes of the mass-to-flux ratio between different parts of the same cloud can even reverse ...
How well can cold-dark-matter substructures account for the observed lensing flux-ratio anomalies?
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...
On the origin of the flux ratio anomaly in quadruple lens systems
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.
Sodium flux ratio through the amiloride-sensitive entry pathway in frog skin
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...
On the Origin of Flux Ratio Anomaly in Quadruple Lens Systems
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}...
Zhang, J.; Griffis, T. J.; Baker, J. M.
2004-12-01
Stable carbon isotope analyses have been used in identifying global carbon sources and sinks and in partitioning ecosystem CO2 exchange into component fluxes. The isotope ratio of ecosystem respiration (δ 13Cr) is a critical parameter in applying stable isotope techniques to carbon cycle problems. The commonly used Keeling plot method in estimating δ 13Cr has limitations related to: 1) insufficient range of CO2 mixing ratio; 2) high sensitivity to curve-fitting techniques; and 3) extrapolation of CO2 mixing ratio beyond observations. In this study, the Keeling plot method was examined and compared with the flux ratio approach using continuous measurements of the mixing ratios of 12CO2 and 13CO2 over an extensive corn canopy during the 2003 growing season. The seasonal variation of δ 13Cr estimated from both methods harmonized with the ecosystem phenology. The δ 13Cr started to increase (became more positive) from mid June and peaked in early August, followed by a decrease into October. The Keeling plot method agreed well with the flux ratio method in the seasonal pattern of δ 13Cr, but tended to give lower values (more negative). The discrepancy between the two approaches was significant in July and August (about 5 per mil) and relatively small in June and September (about 1 to 2 per mil). We examined this discrepancy with respect to wind direction/advection and measurement footprints. In addition, our analysis of high-frequency data (every two minutes) using the flux ratio method indicates that δ 13Cr may vary significantly at short time-scales (e.g., hourly), which could have significant implications for flux partitioning studies.
Infrared Supernova Remnants and their Infrared to X-ray Flux Ratios
Koo, Bon-Chul; Jeong, Il-Gyo; Seok, Ji Yeon; Kim, Hyun-Jeong
2016-01-01
Recent high-resolution infrared space missions have revealed supernova remnants (SNRs) of diverse morphology in infrared (IR) dust emission that is often very different from their X-ray appearance. The observed range of infrared-to-X-ray (IRX) flux ratios of SNRs are also wide. For a sample of 20 Galactic SNRs, we obtain their IR and X-ray properties and investigate the physical causes for such large differences. We find that the observed IRX flux ratios ($R_{IRX.obs}$) are related to the IRX morphology, with SNRs with the largest $R_{IRX,obs}$ showing anticorrelated IRX morphology. By analyzing the relation of $R_{IRX,obs}$ to X-ray and IR parameters, we show that the $R_{IRX,obs}$ of some SNRs agree with theoretical ratios of SNR shocks in which dust grains are heated and destroyed by collisions with plasma particles. For the majority of SNRs, however, $R_{IRX,obs}$ values are either significantly smaller or significantly larger than the theoretical ratios. The latter SNRs have relatively low dust temperatu...
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.
On the Anticorrelation Between Galaxy Light Concentration and X-ray-to-Optical Flux Ratio
Pović, M; García, A M Pérez; Bongiovanni, A; Cepa, J; Lorenzo, M Fernández; Lara-López, M A; González-Serrano, J I; Alfaro, E J
2009-01-01
Active Galactic Nuclei (AGN) play an important role in many aspects of the modern cosmology, and of particular interest is the issue of the interplay between AGN and their host galaxy. Using X-ray and optical data sets, we have explored the properties of a large sample of AGNs in the Subaru/XMM-Newton Deep Survey (SXDS) field, and studied their evolution in relation with the evolution of their host galaxy. We present here an anticorrelation between X-ray-to-optical flux ratio (X/O) and galaxy light concentration (C), which has been found for the first time and might suggest that early type galaxies, having poor matter supply to feed the AGN activity, have lower Eddington rates than those of late type galaxies.
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
How well can cold-dark-matter substructures account for the observed radio flux-ratio anomalies?
Xu, Dandan; Gao, Liang; Wang, Jie; Frenk, Carlos; Mao, Shude; Schneider, Peter; Springel, Volker
2014-01-01
Discrepancies between the observed and model-predicted radio flux ratios are seen in a number of quadruply-lensed quasars. The most favored interpretation of these anomalies is that CDM substructures present in lensing galaxies perturb the lens potentials and alter image magnifications and thus flux ratios. So far no consensus has emerged regarding whether or not the predicted CDM substructure abundance fully accounts for the lensing flux anomaly observations. Accurate modeling relies on a realistic lens sample in terms of both the lens environment and internal structures and substructures. In this paper we construct samples of generalised and specific lens potentials, to which we add (rescaled) subhalo populations from the galaxy-scale Aquarius and the cluster-scale Phoenix simulation suites. We further investigate the lensing effects from subhalos of masses several orders of magnitude below the simulation resolution limit. The resulting flux ratio distributions are compared to the currently best available s...
Monte Carlo simulation of V/III flux ratio influence on GaAs island nucleation during MBE
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.
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.
Effects of Dark Matter Substructures on Gravitational Lensing: Results from the Aquarius Simulations
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...
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.
Constraints on mixed dark matter from anomalous strong lens systems
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 ...
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.
Anomalous transport due to scale anomaly
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.
Constraining warm dark matter using QSO gravitational lensing
Miranda, Marco; Macciò, Andrea V.
2007-12-01
Warm dark matter (WDM) has been invoked to resolve apparent conflicts of cold dark matter (CDM) models with observations on subgalactic scales. In this work, we provide a new and independent lower limit for the WDM particle mass (e.g. sterile neutrino) through the analysis of image fluxes in gravitationally lensed quasi-stellar objects (QSOs). Starting from a theoretical unperturbed cusp configuration, we analyse the effects of intergalactic haloes in modifying the fluxes of QSO multiple images, giving rise to the so-called anomalous flux ratio. We found that the global effect of such haloes strongly depends on their mass/abundance ratio and it is maximized for haloes in the mass range 106-108Msolar. This result opens up a new possibility to constrain CDM predictions on small scales and test different warm candidates, since free streaming of WDM particles can considerably dampen the matter power spectrum in this mass range. As a consequence, while a (Λ)CDM model is able to produce flux anomalies at a level similar to those observed, a WDM model, with an insufficiently massive particle, fails to reproduce the observational evidences. Our analysis suggests a lower limit of a few keV (mν ~ 10) for the mass of WDM candidates in the form of a sterile neutrino. This result makes sterile neutrino WDM less attractive as an alternative to CDM, in good agreement with previous findings from Lyman α forest and cosmic microwave background analysis.
Anomalous Magnetohydrodynamics
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...
Gravitational anomaly and transport phenomena
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...
Anomalous transport due to scale anomaly
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 ...
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...
The X-ray to [Ne V]3426 flux ratio: discovering heavily obscured AGN in the distant Universe
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...
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.
Della Ceca, R.; Carrera, F. J.; Caccianiga, A.; Severgnini, P.; Ballo, L.; Braito, V.; Corral, A.; Del Moro, A.; Mateos, S.; Ruiz, A.; Watson, M. G.
2015-03-01
The cosmic history of the growth of supermassive black holes in galactic centres 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 (˜70 per cent of the sample) in the bright flux regime explored by our survey (f(2-10 keV) ≥ 1.5 × 10-13 erg cm-2 s-1) are associated with obscured AGN (NH > 1022 cm-2), spanning a redshift range between 0.75 and 1 and characterized by 2-10 keV intrinsic luminosities in the QSO regime (e.g. well in excess to 1044 erg s-1). We did not find compelling evidence of Compton thick active galacic nuclei (AGN). Overall, the EXO50 type 2 QSOs do not seem to be different from standard X-ray-selected type 2 QSOs in terms of nuclear absorption; a very high AGN/host galaxy ratio seems to play a major role in explaining their extreme properties. Interestingly, three out of five EXO50 type 2 QSO objects can be classified as extreme dust-obscured galaxies (EDOGs, f24 μm/fR ≥ 2000), suggesting that a very high AGN/host ratios (along with the large amount of dust absorption) could be the natural explanation also for a part of the EDOG population. The remaining two EXO50 sources are classified as BL Lac objects, having rather extreme properties, and which are good candidates for TeV emission.
15 GHz monitoring of the gravitational lens MG 0414+0534
Moore, CB; Hewitt, JN
1997-01-01
We report the results of monitoring the four images of the gravitational lens MG 0414+0534 at 15 GHz. In 35 VLA maps spanning 180 days, we measure root mean square variations in the image light curves of similar to 3.5% mostly due to variations in the flux density calibration. The flux ratios, which
Lee, Young-Min; Chang, Seok-Jun; Heo, Jeong-Eun; Lee, Hee-Won
2016-01-01
Symbiotic stars are regarded as wide binary systems consisting of a hot white dwarf and a mass losing giant. They exhibit unique spectral features at 6825 \\AA\\ and 7082 \\AA, which are formed via Raman scattering of \\ion{O}{6}$\\lambda\\lambda$ 1032 and 1038 with atomic hydrogen. We adopt a Monte Carlo technique to generate the same number of \\ion{O}{6}$\\lambda$1032 and $\\lambda$1038 line photons and compute the flux ratio $F(6825)/F(7082)$ of these Raman scattered \\ion{O}{6} features formed in neutral regions with a simple geometric shape as a function of \\ion{H}{1} column density $N_{HI}$. In cylindrical and spherical neutral regions with the \\ion{O}{6} source embedded inside, the flux ratio $F(6825)/F(7082)$ shows an overall decrease from 3 to 1 as $N_{HI}$ increases in the range $10^{22-24}{\\rm\\ cm^{-2}}$. In the cases of a slab geometry and other geometries with the \\ion{O}{6} source outside the \\ion{H}{1} region, Rayleigh escape operates to lower the flux ratio considerably. For moderate values of $N_{HI}\\...
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.
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.
Fluid/Gravity Correspondence, Second Order Transport and Gravitational Anomaly
Megias, Eugenio
2013-01-01
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.
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
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.
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.
A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
Adriani, O; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bonechi, L; Bongi, M; Bonvicini, V; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carlson, P; Casolino, M; Castellini, G; De Pascale, M P; De Rosa, G; Fedele, D; Galper, A M; Grishantseva, L; Hofverberg, P; Koldashov, S V; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malvezzi, V; Marcelli, L; Menn, W; Mikhailov, V V; Minori, M; Mocchiutti, E; Nagni, M; Orsi, S; Osteria, G; Papini, P; Pearce, M; Picozza, P; Ricci, M; Ricciarini, S B; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Yu I; Taddei, E; Vacchi, A; Vannuccini, E; Vasilyev, G; Voronov, S A; Yurkin, Y T; Zampa, G; Zampa, N; Zverev, V G
2008-01-01
A new measurement of the cosmic ray antiproton-to-proton flux ratio between 1 and 100 GeV is presented. The results were obtained with the PAMELA experiment, which was launched into low-earth orbit on-board the Resurs-DK1 satellite on June 15th 2006. PAMELA is equipped with a silicon-microstrip magnetic spectrometer and a silicon-tungsten imaging calorimeter and has been collecting data since July 2006. During 500 days of data collection a total of about 1000 antiprotons have been identified, including 100 above an energy of 20 GeV. The high-energy results are a ten-fold improvement in statistics with respect to all previously published data. The antiproton-to-proton flux ratio increases smoothly with energy up to about 10 GeV, in agreement with previous experiments, and then levels off. The data follow the trend expected from secondary production calculations and significantly constrain contributions from exotic sources, e.g. dark matter particle annihilations.
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...
Holographic Gravitational Anomaly in First and Second Order Hydrodynamics
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.
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.
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.
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.
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.)
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)
Classical Gravitational Interactions and Gravitational Lorentz Force
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
In quantum gauge theory of gravity, the gravitational field is represented by gravitational gauge field.The field strength of gravitational gauge field has both gravitoelectric component and gravitomagnetic component. In classical level, gauge theory of gravity gives classical Newtonian gravitational interactions in a relativistic form. Besides,it gives gravitational Lorentz force, which is the gravitational force on a moving object in gravitomagnetic field The direction of gravitational Lorentz force is not the same as that of classical gravitational Newtonian force. Effects of gravitational Lorentz force should be detectable, and these effects can be used to discriminate gravitomagnetic field from ordinary electromagnetic magnetic field.
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.
Turner, Edwin L.
1989-01-01
Recent observational and theoretical investigations of gravitational-lens phenomena are reviewed, and sample numerical data are presented in tables. Particular attention is given to luminous arcs, radio rings, galaxy-quasar associations, the problem of deriving actually or practically unique models of individual lens systems, and time delays and the Hubble constant.
A New Channel for Detecting Dark Matter Substructure in Galaxies: Gravitational Lens Time Delays
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...
Conformal Anomalies and Gravitational Waves
Meissner, Krzysztof A
2016-01-01
We argue that the presence of conformal anomalies in gravitational theories can lead to observable modifications to Einstein's equations via the induced anomalous effective actions, whose non-localities can overwhelm the smallness of the Planck scale. The fact that no such effects have been seen in recent cosmological or gravitational wave observations therefore imposes strong restrictions on the field content of possible extensions of Einstein's theory: all viable theories should have vanishing conformal anomalies. We then show that, among presently known theories, a complete cancellation of conformal anomalies in $D=4$ for both the $C^2$ invariant and the Euler (Gauss-Bonnet) invariant $E_4$ can only be achieved for $N$-extended supergravities with $N\\geq 5$, as well as for M theory compactified to four dimensions.
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.
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...
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.
Dirac particle spin in strong gravitational fields
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.
Aguilar, M; Ali Cavasonza, L; Alpat, B; Ambrosi, G; Arruda, L; Attig, N; Aupetit, S; Azzarello, P; Bachlechner, A; Barao, F; Barrau, A; Barrin, L; Bartoloni, A; Basara, L; Başeǧmez-du Pree, S; Battarbee, M; Battiston, R; Bazo, J; Becker, U; Behlmann, M; Beischer, B; Berdugo, J; Bertucci, B; Bindi, V; Boella, G; de Boer, W; Bollweg, K; Bonnivard, V; Borgia, B; Boschini, M J; Bourquin, M; Bueno, E F; Burger, J; Cadoux, F; Cai, X D; Capell, M; Caroff, S; Casaus, J; Castellini, G; Cernuda, I; Cervelli, F; Chae, M J; Chang, Y H; Chen, A I; Chen, G M; Chen, H S; Cheng, L; Chou, H Y; Choumilov, E; Choutko, V; Chung, C H; Clark, C; Clavero, R; Coignet, G; Consolandi, C; Contin, A; Corti, C; Coste, B; Creus, W; Crispoltoni, M; Cui, Z; Dai, Y M; Delgado, C; Della Torre, S; Demirköz, M B; Derome, L; Di Falco, S; Dimiccoli, F; Díaz, C; von Doetinchem, P; Dong, F; Donnini, F; Duranti, M; D'Urso, D; Egorov, A; Eline, A; Eronen, T; Feng, J; Fiandrini, E; Finch, E; Fisher, P; Formato, V; Galaktionov, Y; Gallucci, G; García, B; García-López, R J; Gargiulo, C; Gast, H; Gebauer, I; Gervasi, M; Ghelfi, A; Giovacchini, F; Goglov, P; Gómez-Coral, D M; Gong, J; Goy, C; Grabski, V; Grandi, D; Graziani, M; Guerri, I; Guo, K H; Habiby, M; Haino, S; Han, K C; He, Z H; Heil, M; Hoffman, J; Hsieh, T H; Huang, H; Huang, Z C; Huh, C; Incagli, M; Ionica, M; Jang, W Y; Jinchi, H; Kang, S C; Kanishev, K; Kim, G N; Kim, K S; Kirn, Th; Konak, C; Kounina, O; Kounine, A; Koutsenko, V; Krafczyk, M S; La Vacca, G; Laudi, E; Laurenti, G; Lazzizzera, I; Lebedev, A; Lee, H T; Lee, S C; Leluc, C; Li, H S; Li, J Q; Li, J Q; Li, Q; Li, T X; Li, W; Li, Z H; Li, Z Y; Lim, S; Lin, C H; Lipari, P; Lippert, T; Liu, D; Liu, Hu; Lu, S Q; Lu, Y S; Luebelsmeyer, K; Luo, F; Luo, J Z; Lv, S S; Majka, R; Mañá, C; Marín, J; Martin, T; Martínez, G; Masi, N; Maurin, D; Menchaca-Rocha, A; Meng, Q; Mo, D C; Morescalchi, L; Mott, P; Nelson, T; Ni, J Q; Nikonov, N; Nozzoli, F; Nunes, P; Oliva, A; Orcinha, M; Palmonari, F; Palomares, C; Paniccia, M; Pauluzzi, M; Pensotti, S; Pereira, R; Picot-Clemente, N; Pilo, F; Pizzolotto, C; Plyaskin, V; Pohl, M; Poireau, V; Putze, A; Quadrani, L; Qi, X M; Qin, X; Qu, Z Y; Räihä, T; Rancoita, P G; Rapin, D; Ricol, J S; Rodríguez, I; Rosier-Lees, S; Rozhkov, A; Rozza, D; Sagdeev, R; Sandweiss, J; Saouter, P; Schael, S; Schmidt, S M; Schulz von Dratzig, A; Schwering, G; Seo, E S; Shan, B S; Shi, J Y; Siedenburg, T; Son, D; Song, J W; Sun, W H; Tacconi, M; Tang, X W; Tang, Z C; Tao, L; Tescaro, D; Ting, Samuel C C; Ting, S M; Tomassetti, N; Torsti, J; Türkoğlu, C; Urban, T; Vagelli, V; Valente, E; Vannini, C; Valtonen, E; Vázquez Acosta, M; Vecchi, M; Velasco, M; Vialle, J P; Vitale, V; Vitillo, S; Wang, L Q; Wang, N H; Wang, Q L; Wang, X; Wang, X Q; Wang, Z X; Wei, C C; Weng, Z L; Whitman, K; Wienkenhöver, J; Willenbrock, M; Wu, H; Wu, X; Xia, X; Xiong, R Q; Xu, W; Yan, Q; Yang, J; Yang, M; Yang, Y; Yi, H; Yu, Y J; Yu, Z Q; Zeissler, S; Zhang, C; Zhang, J; Zhang, J H; Zhang, S D; Zhang, S W; Zhang, Z; Zheng, Z M; Zhu, Z Q; Zhuang, H L; Zhukov, V; Zichichi, A; Zimmermann, N; Zuccon, P
2016-08-26
A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×10^{5} antiproton events and 2.42×10^{9} proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500 GV, the antiproton p[over ¯], proton p, and positron e^{+} fluxes are found to have nearly identical rigidity dependence and the electron e^{-} flux exhibits a different rigidity dependence. Below 60 GV, the (p[over ¯]/p), (p[over ¯]/e^{+}), and (p/e^{+}) flux ratios each reaches a maximum. From ∼60 to ∼500 GV, the (p[over ¯]/p), (p[over ¯]/e^{+}), and (p/e^{+}) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos. PMID:27610839
Aguilar, M.; Ali Cavasonza, L.; Alpat, B.; Ambrosi, G.; Arruda, L.; Attig, N.; Aupetit, S.; Azzarello, P.; Bachlechner, A.; Barao, F.; Barrau, A.; Barrin, L.; Bartoloni, A.; Basara, L.; BaşeÇ§mez-du Pree, S.; Battarbee, M.; Battiston, R.; Bazo, J.; Becker, U.; Behlmann, M.; Beischer, B.; Berdugo, J.; Bertucci, B.; Bindi, V.; Boella, G.; de Boer, W.; Bollweg, K.; Bonnivard, V.; Borgia, B.; Boschini, M. J.; Bourquin, M.; Bueno, E. F.; Burger, J.; Cadoux, F.; Cai, X. D.; Capell, M.; Caroff, S.; Casaus, J.; Castellini, G.; Cernuda, I.; Cervelli, F.; Chae, M. J.; Chang, Y. H.; Chen, A. I.; Chen, G. M.; Chen, H. S.; Cheng, L.; Chou, H. Y.; Choumilov, E.; Choutko, V.; Chung, C. H.; Clark, C.; Clavero, R.; Coignet, G.; Consolandi, C.; Contin, A.; Corti, C.; Coste, B.; Creus, W.; Crispoltoni, M.; Cui, Z.; Dai, Y. M.; Delgado, C.; Della Torre, S.; Demirköz, M. B.; Derome, L.; Di Falco, S.; Dimiccoli, F.; Díaz, C.; von Doetinchem, P.; Dong, F.; Donnini, F.; Duranti, M.; D'Urso, D.; Egorov, A.; Eline, A.; Eronen, T.; Feng, J.; Fiandrini, E.; Finch, E.; Fisher, P.; Formato, V.; Galaktionov, Y.; Gallucci, G.; García, B.; García-López, R. J.; Gargiulo, C.; Gast, H.; Gebauer, I.; Gervasi, M.; Ghelfi, A.; Giovacchini, F.; Goglov, P.; Gómez-Coral, D. M.; Gong, J.; Goy, C.; Grabski, V.; Grandi, D.; Graziani, M.; Guerri, I.; Guo, K. H.; Habiby, M.; Haino, S.; Han, K. C.; He, Z. H.; Heil, M.; Hoffman, J.; Hsieh, T. H.; Huang, H.; Huang, Z. C.; Huh, C.; Incagli, M.; Ionica, M.; Jang, W. Y.; Jinchi, H.; Kang, S. C.; Kanishev, K.; Kim, G. N.; Kim, K. S.; Kirn, Th.; Konak, C.; Kounina, O.; Kounine, A.; Koutsenko, V.; Krafczyk, M. S.; La Vacca, G.; Laudi, E.; Laurenti, G.; Lazzizzera, I.; Lebedev, A.; Lee, H. T.; Lee, S. C.; Leluc, C.; Li, H. S.; Li, J. Q.; Li, J. Q.; Li, Q.; Li, T. X.; Li, W.; Li, Z. H.; Li, Z. Y.; Lim, S.; Lin, C. H.; Lipari, P.; Lippert, T.; Liu, D.; Liu, Hu; Lu, S. Q.; Lu, Y. S.; Luebelsmeyer, K.; Luo, F.; Luo, J. Z.; Lv, S. S.; Majka, R.; Mañá, C.; Marín, J.; Martin, T.; Martínez, G.; Masi, N.; Maurin, D.; Menchaca-Rocha, A.; Meng, Q.; Mo, D. C.; Morescalchi, L.; Mott, P.; Nelson, T.; Ni, J. Q.; Nikonov, N.; Nozzoli, F.; Nunes, P.; Oliva, A.; Orcinha, M.; Palmonari, F.; Palomares, C.; Paniccia, M.; Pauluzzi, M.; Pensotti, S.; Pereira, R.; Picot-Clemente, N.; Pilo, F.; Pizzolotto, C.; Plyaskin, V.; Pohl, M.; Poireau, V.; Putze, A.; Quadrani, L.; Qi, X. M.; Qin, X.; Qu, Z. Y.; Räihä, T.; Rancoita, P. G.; Rapin, D.; Ricol, J. S.; Rodríguez, I.; Rosier-Lees, S.; Rozhkov, A.; Rozza, D.; Sagdeev, R.; Sandweiss, J.; Saouter, P.; Schael, S.; Schmidt, S. M.; Schulz von Dratzig, A.; Schwering, G.; Seo, E. S.; Shan, B. S.; Shi, J. Y.; Siedenburg, T.; Son, D.; Song, J. W.; Sun, W. H.; Tacconi, M.; Tang, X. W.; Tang, Z. C.; Tao, L.; Tescaro, D.; Ting, Samuel C. C.; Ting, S. M.; Tomassetti, N.; Torsti, J.; Türkoǧlu, C.; Urban, T.; Vagelli, V.; Valente, E.; Vannini, C.; Valtonen, E.; Vázquez Acosta, M.; Vecchi, M.; Velasco, M.; Vialle, J. P.; Vitale, V.; Vitillo, S.; Wang, L. Q.; Wang, N. H.; Wang, Q. L.; Wang, X.; Wang, X. Q.; Wang, Z. X.; Wei, C. C.; Weng, Z. L.; Whitman, K.; Wienkenhöver, J.; Willenbrock, M.; Wu, H.; Wu, X.; Xia, X.; Xiong, R. Q.; Xu, W.; Yan, Q.; Yang, J.; Yang, M.; Yang, Y.; Yi, H.; Yu, Y. J.; Yu, Z. Q.; Zeissler, S.; Zhang, C.; Zhang, J.; Zhang, J. H.; Zhang, S. D.; Zhang, S. W.; Zhang, Z.; Zheng, Z. M.; Zhu, Z. Q.; Zhuang, H. L.; Zhukov, V.; Zichichi, A.; Zimmermann, N.; Zuccon, P.; AMS Collaboration
2016-08-01
A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49 ×1 05 antiproton events and 2.42 ×1 09 proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ˜60 to ˜500 GV , the antiproton p ¯, proton p , and positron e+ fluxes are found to have nearly identical rigidity dependence and the electron e- flux exhibits a different rigidity dependence. Below 60 GV, the (p ¯/p ), (p ¯/e+), and (p /e+) flux ratios each reaches a maximum. From ˜60 to ˜500 GV , the (p ¯/p ), (p ¯/e+), and (p /e+) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.
Gravitational and Anti-gravitational Applications
Ellman, Roger
1998-01-01
It is now possible to partially deflect gravitation away from an object so that the gravitational attraction on the object is reduced. That effect makes it possible to extract energy from the gravitational field, which makes the generation of gravito-electric power technologically feasible. Such plants would be similar to hydro-electric plants and would have their advantages of not needing fuel and not polluting the environment. Physically, the action of deflecting away gravitational attracti...
Anomalous Chiral Superfluidity
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 ...
Hydrodynamic Waves in an Anomalous Charged Fluid
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...
A possible explanation for the anomalous acceleration of Pioneer 10
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...
Bowler, Michael George
1976-01-01
Gravitation and Relativity generalizes Isaac Newton's theory of gravitation using the elementary tools of Albert Einstein's special relativity. Topics covered include gravitational waves, martian electrodynamics, relativistic gravitational fields and gravitational forces, the distortion of reference frames, and the precession of the perihelion of Mercury. Black holes and the geometry of spacetime also receive consideration. This book is comprised of 10 chapters; the first of which briefly reviews special relativity, with the emphasis on the Lorentz covariance of the equations of physics. This
Conditions for stimulated emission in anomalous gravity-superconductors interactions
Modanese, G
2009-01-01
Several authors have studied the generation of gravitational fields by condensed-matter systems in non-extreme density conditions. General Relativity and lowest-order perturbative Quantum Gravity predict in this case an extremely small emission rate, so these phenomena can become relevant only if some strong quantum effect occurs. Quantum aspects of gravity are still poorly understood. It is believed that they could play a role in systems which exhibit macroscopic quantum coherence, like superconductors and superfluids, leading to an "anomalous" coupling between matter and field. We mention here recent work in this field by Woods, Chiao, Becker, Agop et al., Ummarino, Kiefer and Weber. New results are presented concerning anomalous stimulated gravitational emission in a layered superconductor like YBCO. We model the superconductor as an array of intrinsic Josephson junctions. The superconducting parameters are defined by our preliminary measurements with melt-textured samples. We write explicitly and solve nu...
Source-position transformation -- an approximate invariance in strong gravitational lensing
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...
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.
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).
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.
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
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.
Anomalous chiral superfluidity
Energy Technology Data Exchange (ETDEWEB)
Lublinsky, Michael, E-mail: lublinsky@phys.uconn.ed [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Physics Department, Ben-Gurion University, Beer Sheva 84105 (Israel); Zahed, Ismail [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)
2010-02-08
We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavor 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 briefly noted.
Anomalous pion decay revisited
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.
Beta Function and Anomalous Dimensions
DEFF Research Database (Denmark)
Pica, Claudio; Sannino, Francesco
2011-01-01
We demonstrate that it is possible to determine the coefficients of an all-order beta function linear in the anomalous dimensions using as data the two-loop coefficients together with the first one of the anomalous dimensions which are universal. The beta function allows to determine the anomalous...
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.
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. ...
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).
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)
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…
Anomalous diffusion of epicentres
Sotolongo-Costa, Oscar; Posadas, A; Luzon, F
2007-01-01
The classification of earthquakes in main shocks and aftershocks by a method recently proposed by M. Baiesi and M. Paczuski allows to the generation of a complex network composed of clusters that group the most correlated events. The spatial distribution of epicentres inside these structures corresponding to the catalogue of earthquakes in the eastern region of Cuba shows anomalous anti-diffusive behaviour evidencing the attractive nature of the main shock and the possible description in terms of fractional kinetics.
Lapas, Luciano C.; Ferreira, Rogelma M. S.; Oliveira, Fernando A.; Rubí, J. Miguel
2014-01-01
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergo 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 ma...
Nonlocal Anomalous Hall Effect
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.
Nonlocal Anomalous Hall Effect.
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.
Holographic entanglement entropy and gravitational anomalies
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.
The Importance of Intergalactic Structure to Gravitationally Lensed Quasars
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...
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
Gravitational waves from inflation
Guzzetti, M. C.; Bartolo, N.; Liguori, M.; Matarrese, S.
2016-09-01
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 tensor-to-scalar ratio r and tensor spectral index nT. In light of the prospects for (directly/indirectly) detecting primordial gravitational waves, we give the expected present-day gravitational radiation spectral energy-density, highlighting the main characteristics imprinted by the cosmic thermal history, and we outline the signatures left by gravitational waves on the Cosmic Microwave Background and some imprints in the Large-Scale Structure of the Universe. Finally, current bounds and prospects of detection for inflationary gravitational waves are summarized.
The quantum anomalous Hall effect
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...
Anomalous radiative transitions
Ishikawa, Kenzo; Tobita, Yutaka
2014-01-01
Anomalous transitions involving photons derived by many-body interaction of the form, $\\partial_{\\mu} G^{\\mu}$, in the standard model are studied. This does not affect the equation of motion in the bulk, but makes wave functions modified, and causes the unusual transition characterized by the time-independent probability. In the transition probability at a time-interval T expressed generally in the form $P=T \\Gamma_0 +P^{(d)}$, now with $\\Gamma_0=0, P^{(d)} \
Dark Matter Gravitational Interactions
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...
Theory of gravitational interactions
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...
Gravitational waves from inflation
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...
Weber's gravitational force as static weak field approximation
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.
Gravitation and electromagnetism
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...
Fickian dispersion is anomalous
Cushman, John H.; O'Malley, Dan
2015-12-01
The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.
Pulsars and Gravitational Waves
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.
Vlokh, R.; Kostyrko, M.
2006-01-01
Nonlinear effect of the gravitation field of spherically symmetric mass on the gravitational coefficient G has been analysed. In frame of the approaches of parametric optics and gravitation nonlinearity we have shown that the gravitation field of spherically symmetric mass can lead to changes in the gravitational coefficient G.
Fractal model of anomalous diffusion.
Gmachowski, Lech
2015-12-01
An equation of motion is derived from fractal analysis of the Brownian particle trajectory in which the asymptotic fractal dimension of the trajectory has a required value. The formula makes it possible to calculate the time dependence of the mean square displacement for both short and long periods when the molecule diffuses anomalously. The anomalous diffusion which occurs after long periods is characterized by two variables, the transport coefficient and the anomalous diffusion exponent. An explicit formula is derived for the transport coefficient, which is related to the diffusion constant, as dependent on the Brownian step time, and the anomalous diffusion exponent. The model makes it possible to deduce anomalous diffusion properties from experimental data obtained even for short time periods and to estimate the transport coefficient in systems for which the diffusion behavior has been investigated. The results were confirmed for both sub and super-diffusion.
Spectrum of anomalous magnetohydrodynamics
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.
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.
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...
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.
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...
Gravitational Lensing in Astronomy
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...
Anomalous precession of planets on a Weyl conformastatic solution
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...
A New Channel for Detecting Dark Matter Substructure in Galaxies: Gravitational Lens Time Delays
Keeton, Charles R.; Moustakas, Leonidas A.
2009-07-01
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 langm 2rang/langmrang). 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 possibility that this effect has already been observed in RX J1131-1231.
Conklin, John
2016-03-01
With the expected direct detection of gravitational waves by Advanced LIGO and pulsar timing arrays in the near future, and with the recent launch of LISA Pathfinder this can arguably be called the decade of gravitational waves. Low frequency gravitational waves in the mHz range, which can only be observed from space, provide the richest science and complement high frequency observatories on the ground. A space-based observatory will improve our understanding of the formation and growth of massive black holes, create a census of compact binary systems in the Milky Way, test general relativity in extreme conditions, and enable searches for new physics. LISA, by far the most mature concept for detecting gravitational waves from space, has consistently ranked among the nation's top priority large science missions. In 2013, ESA selected the science theme ``The Gravitational Universe'' for its third large mission, L3, under the Cosmic Visions Program, with a planned launch date of 2034. NASA has decided to join with ESA on the L3 mission as a junior partner and has recently assembled a study team to provide advice on how NASA might contribute to the European-led mission. This talk will describe these efforts and the activities of the Gravitational Wave Science Interest Group and the L3 Study Team, which will lead to the first space-based gravitational wave observatory.
Generalized Gravitational Entropy of Interacting Scalar Field and Maxwell Field
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.
Gravitational Waves and the Fate of Scalar-Tensor Gravity
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...
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
Gravitational lensing of quasars
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...
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.
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...
CERN. Geneva
2016-01-01
In the past year, the LIGO-Virgo Collaboration announced the first secure detection of gravitational waves. This discovery heralds the beginning of gravitational wave astronomy: the use of gravitational waves as a tool for studying the dense and dynamical universe. In this talk, I will describe the full spectrum of gravitational waves, from Hubble-scale modes, through waves with periods of years, hours and milliseconds. I will describe the different techniques one uses to measure the waves in these bands, current and planned facilities for implementing these techniques, and the broad range of sources which produce the radiation. I will discuss what we might expect to learn as more events and sources are measured, and as this field matures into a standard part of the astronomical milieu.
seyithocuk; jjeherrera; eltodesukane; GrahamRounce; rloldershaw; Beaker, Dr; Sandhu, G. S.; Ophiuchi
2016-03-01
In reply to the news article on the LIGO collaboration's groundbreaking detection of gravitational waves, first predicted by Einstein 100 years ago, from two black holes colliding (pp5, 6-7 and http://ow.ly/Ylsyt).
Gravitational Holographic Teleportation
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.
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
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.
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.
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.)
Astrometric detection of gravitational effects of quantum vacuum
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.
A Gedankenexperiment in Gravitation
Gaspar, Yves
2011-01-01
In this paper we consider a thought experiment involving the effect of gravitation on an ideal scale containing a photon. If the tidal forces inherent to a gravitational field are neglected, then one is led to scenario which seems to bring about perpetual motion violating the first and second principle of thermodynamics. The tidal effects of gravity must neccessarily be included in order to obtain a consistent physical theory. As a result, Albert Einstein's thought experiments according to which the physical effects of inertia in an accelerated reference frame are equivalent to the effects of gravity in a frame at rest on the surface of a massive body must be reconsidered, since linearly accelerated frames do not produce tidal effects. We argue that the equivalence between inertial effects and gravitation can be restored for rotating frames and in this context a relation with the possible nature of quantum gravity is conjectured.
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...
Cosmology of gravitational vacuum
Burdyuzha, V; Pacheco, J
2008-01-01
Production of gravitational vacuum defects and their contribution to the energy density of our Universe are discussed. These topological microstructures (defects) could be produced in the result of creation of the Universe from "nothing" when a gravitational vacuum condensate has appeared. They must be isotropically distributed over the isotropic expanding Universe. After Universe inflation these microdefects are smoothed, stretched and broken up. A part of them could survive and now they are perceived as the structures of Lambda-term and an unclustered dark matter. It is shown that the parametrization noninvariance of the Wheeler-De Witt equation can be used to describe phenomenologically vacuum topological defects of different dimensions (worm-holes, micromembranes, microstrings and monopoles). The mathematical illustration of these processes may be the spontaneous breaking of the local Lorentz-invariance of the quasi-classical equations of gravity. Probably the gravitational vacuum condensate has fixed tim...
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
Wilhelm, Klaus; Dwivedi, Bhola N.
2014-08-01
The study of the gravitational redshift-a relative wavelength increase of ≈2×10-6 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 ratio of 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 in such an atom is approximately 3×10-21. A comparison of this ratio with the predicted and observed solar redshift indicates a discrepancy of many orders of magnitude. With Einstein’s early assumption that the frequencies of spectral lines depend only on the generating ions themselves as starting point, we show that a solution can be formulated based on a two-step process in analogy with Fermi’s treatment of the Doppler effect. It provides a sequence of physical processes in line with the conservation of energy and momentum resulting in the observed shift and does not employ a geometric description. The gravitational field affects the release of the photon and not the atomic transition. The control parameter is the speed of light. The atomic emission is then contrasted with the gravitational redshift of matter-antimatter annihilation events.
Gravitation: Foundations and Frontiers
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.
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.
Directory of Open Access Journals (Sweden)
Patrick Das Gupta
2009-10-01
Full Text Available 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 discussion on an important prediction of general relativity, namely, the existence of gravitational waves and the attempts to detect them. Finally, the article touches on the current challenges facing the gravity researchers.
Gravitational form factors and nucleon spin structure
Teryaev, O. V.
2016-10-01
Nucleon scattering by the classical gravitational field is described by the gravitational (energy-momentum tensor) form factors (GFFs), which also control the partition of nucleon spin between the total angular momenta of quarks and gluons. The equivalence principle (EP) for spin dynamics results in the identically zero anomalous gravitomagnetic moment, which is the straightforward analog of its electromagnetic counterpart. The extended EP (ExEP) describes its (approximate) validity separately for quarks and gluons and, in turn, results in equal partition of the momentum and total angular momentum. It is violated in quantum electrodynamics and perturbative quantum chromodynamics (QCD), but may be restored in nonperturbative QCD because of confinement and spontaneous chiral symmetry breaking, which is supported by models and lattice QCD calculations. It may, in principle, be checked by extracting the generalized parton distributions from hard exclusive processes. The EP for spin-1 hadrons is also manifested in inclusive processes (deep inelastic scattering and the Drell-Yan process) in sum rules for tensor structure functions and parton distributions. The ExEP may originate in either gravity-proof confinement or in the closeness of the GFF to its asymptotic values in relation to the mediocrity principle. The GFFs in time-like regions reveal some similarity between inflation and annihilation.
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)
Anomalous-viscosity current drive
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.
Anomalous magnetic moment of anyons
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.
QCD Anomalous Structure of Electron
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.
Gravitational Structure Formation
Labini, Francesco Sylos; Baertschiger, Thierry
2005-01-01
We discuss the formation of the first structures in gravitational N-body simulations. The role of two-body interaction is found to be a crucial element and an analogy with the dynamics of the Coulomb lattice, well-studied in solid state physics, is discussed.
Static Gravitational Global Monopoles
Liebling, S L
2000-01-01
Static solutions in spherical symmetry are found for gravitating global monopoles. Regular solutions lacking a horizon are found for $\\eta \\sqrt{3/8\\pi} \\approx 0.3455$ is consistent with findings that topological inflation begins at $\\eta \\approx 0.33$.
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
Spitzer observations of a gravitationally lensed quasar, QSO 2237+0305
Agol, Eric; Gorjian, Varoujan; Kimball, Amy; 10.1088/0004-637X/697/2/1010
2009-01-01
The four-image gravitationally lensed quasar QSO 2237+0305 is microlensed by stars in the lens galaxy. The amplitude of microlensing variability can be used to infer the relative size of the quasar as a function of wavelength; this provides a test of quasar models. Toward this end, we present Spitzer Space Telescope Infrared Spectrograph and Infrared Array Camera (IRAC) observations of QSO 2237+0305, finding the following. (1) The infrared (IR) spectral energy distribution (SED) is similar to that of other bright radio-quiet quasars, contrary to an earlier claim. (2) A dusty torus model with a small opening angle fits the overall shape of the IR SED well, but the quantitative agreement is poor due to an offset in wavelength of the silicate feature. (3) The flux ratios of the four lensed images can be derived from the IRAC data despite being unresolved. We find that the near-IR fluxes are increasingly affected by microlensing toward shorter wavelengths. (4) The wavelength dependence of the IRAC flux ratios is ...
Source-position transformation: an approximate invariance in strong gravitational lensing
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.
Gravitational wave astronomy and cosmology
Hughes, Scott A
2014-01-01
The first direct observation of gravitational waves' action upon matter has recently been reported by the BICEP2 experiment. Advanced ground-based gravitational-wave detectors are being installed. They will soon be commissioned, and then begin searches for high-frequency gravitational waves at a sensitivity level that is widely expected to reach events involving compact objects like stellar mass black holes and neutron stars. Pulsar timing arrays continue to improve the bounds on gravitational waves at nanohertz frequencies, and may detect a signal on roughly the same timescale as ground-based detectors. The science case for space-based interferometers targeting millihertz sources is very strong. The decade of gravitational-wave discovery is poised to begin. In this writeup of a talk given at the 2013 TAUP conference, we will briefly review the physics of gravitational waves and gravitational-wave detectors, and then discuss the promise of these measurements for making cosmological measurements in the near fu...
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.
Gravitationally induced quantum transitions
Landry, A
2016-01-01
In this letter, we calculate the probability for resonantly induced 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 ultra cold neutrons (UCN), which are organized according to the energy levels of the Schr\\"odinger equation in the presence of the earth's gravitational field. Transitions between energy levels are induced by an oscillating driving force of frequency $\\omega$. The driving force is created by oscillating a macroscopic mass in the neighbourhood of the system of neutrons. The neutrons decay in 880 seconds while the probability of transitions increase as $t^2$. Hence the optimal strategy is to drive the system for 2 lifetimes. The transition amplitude then is of the order of $1.06\\times 10^{-5}$ hence with a million ultra cold neutrons, one should be able to observe transitions.
Gravitation and electromagnetism
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).
Cosmology with Gravitational Lensing
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...
Burinskii, Alexander
2015-01-01
As is known, the gravitational and electromagnetic (EM) field of the Dirac electron is described by an over-extremal Kerr-Newman (KN) black hole (BH) solution which has the naked singular ring and two-sheeted topology. This space is regulated by the formation of a regular source based on the Higgs mechanism of broken symmetry. This source shares much in common with the known MIT- and SLAC-bag models, but has the important advantage, of being in accordance with gravitational and electromagnetic field of the external KN solution. The KN bag model is flexible. At rotations, it takes the shape of a thin disk, and similar to other bag models, under deformations it creates a string-like structure which is positioned along the sharp border of the disk.
Gravitationally induced quantum transitions
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.
Spacetime, Geometry and Gravitation
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.
Gravitational Wave Confusion Noise
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, ...
Gravitational lensing by wormholes
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.
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.
EDITORIAL: Focus on Gravitational Lensing
Jain, Bhuvnesh
2007-11-01
or quasars which are strongly magnified and sheared. In the last decade, double and quadruply imaged systems due to galactic lenses have been studied with optical and radio observations. An interesting result obtained from the flux ratio 'anomalies' of quadruply imaged systems is the statistical detection of dark sub-clumps in galaxy halos. More broadly, while we have learned a lot about the mass distribution in lens galaxies and improved time delay constraints on the Hubble constant, the limitations of cosmological studies with strong lensing due to uncertainties in lens mass models have also come to be appreciated. That said, progress will no doubt continue with qualitative advances in observations such as astrometric counterparts to the flux anomalies, clever ideas such as the use of spectroscopic signatures to assemble the SLACS lens sample, and combining optical imaging, spectroscopy and radio data to continue the quest for a set of golden lenses to measure the Hubble constant. Galaxy clusters are a fascinating arena for studying the distribution of dark and baryonic matter. Weak and strong lensing information can be combined with dynamical information from the spectroscopic measurements of member galaxies and x-ray/Sunyaev Zeldovich measurements of the hot ionized gas. Hubble Space Telescope observations have yielded spectacular images of clusters, such as Abell 1689, which has over a hundred multiply imaged arcs. Mass measurements have progressed to the level of 10 percent accuracy for several clusters. Unfortunately, it is unclear if one can do much better for individual clusters given inherent limitations such as unknown projection effects. The statistical study of clusters is likely to remain a promising way to study dark matter, gravity theories, and cosmology. Techniques to combine weak and strong lensing information to obtain the mass distribution of clusters have also advanced, and work continues on parameter-free techniques that are agnostic to the
Minimal muon anomalous magnetic moment
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.
Electrostatic-gravitational oscillator
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...
Anomalous Diffusion in Velocity Space
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. ...
Anomalous Proper-Motions in the Cygnus Super Bubble Region
Comeron, F.; Torra, J.; Jordi, C.; Gomez, A. E.
1993-10-01
In an analysis of proper motions of O and B stars contained in the Input Catalogue for Hipparcos, we have found a clear deviation from the expected pattern of systematic motions which can be readily identified with the associations Cygnus OB1 and Cygnus OB9, located near the edge of the Cygnus Superbubble. The anomalous motions are directed outwards from the center of the Superbubble, which is coincident with the association Cygnus OB2. This seems to support the hypothesis of a strong stellar and supernova activity in Cygnus OB2 giving rise to the Superbubble and, by means of gravitational instabilities in its boundaries, to Cygnus CB1 and Cygnus OB9. New uvbyβ aperture photometry of selected O and B stars in the area of Cygnus OB1 and Cygnus OB9 is also presented and analyzed in this paper.
(Non)renormalization of Anomalous Conductivities and Holography
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...
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
Gravitational Waves Astronomy: a cornerstone for gravitational theories
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).
Gravitomagnetic corrections on gravitational waves
Capozziello, S; Forte, L; Garufi, F; Milano, L
2009-01-01
Gravitational waveforms and production could be considerably affected by gravitomagnetic corrections considered in relativistic theory of orbits. Beside the standard periastron effect of General Relativity, new nutation effects come out when c^{-3} corrections are taken into account. Such corrections emerge as soon as matter-current densities and vector gravitational potentials cannot be discarded into dynamics. We study the gravitational waves emitted through the capture, in the gravitational field of massive binary systems (e.g. a very massive black hole on which a stellar object is inspiralling) via the quadrupole approximation, considering precession and nutation effects. We present a numerical study to obtain the gravitational wave luminosity, the total energy output and the gravitational radiation amplitude. From a crude estimate of the expected number of events towards peculiar targets (e.g. globular clusters) and in particular, the rate of events per year for dense stellar clusters at the Galactic Cen...
Probing Positron Gravitation at HERA
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.
Thought Experiments on Gravitational Forces
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...
Gravitational Waves from the Phase Transition of a Non-linearly Realised Electroweak Gauge Symmetry
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.
Einstein's gravitational field
Brown, P M
2002-01-01
There exists some confusion, as evidenced in the literature, regarding the nature of the gravitational field in Einstein's General Theory of Relativity. It is argued here the this confusion is a result of a change in interpretation of the gravitationla field. Einstein identified the existence of gravity with the inertial motion of accelerating bodies (i.e. bodies in free-fall) whereas contemporary physicists identify the existence of gravity with space-time curvature (i.e. tidal forces). The interpretation of gravity as a curvature in space-time is an interpretation Einstein did not agree with.
The antimatter gravitational field
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 .
Piecewise flat gravitational waves
Energy Technology Data Exchange (ETDEWEB)
Van de Meent, Maarten, E-mail: M.vandeMeent@uu.nl [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, PO Box 80.195, 3508 TD Utrecht (Netherlands)
2011-04-07
We examine the continuum limit of the piecewise flat locally finite gravity model introduced by 't Hooft. In the linear weak field limit, we find the energy-momentum tensor and metric perturbation of an arbitrary configuration of defects. The energy-momentum turns out to be restricted to satisfy certain conditions. The metric perturbation is mostly fixed by the energy-momentum except for its lightlike modes which reproduce linear gravitational waves, despite no such waves being present at the microscopic level.
Gravitational Lensing & Stellar Dynamics
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.
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.
Fluid/Gravity Correspondence, Second Order Transport and Gravitational Anomaly***
Megías, Eugenio; Pena-Benitez, Francisco
2014-03-01
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. Talk given by E. Megías at the International Nuclear Physics Conference INPC 2013, 2-7 June 2013, Firenze, Italy.Supported by Plan Nacional de Altas Energías (FPA2009-07908, FPA2011-25948), Spanish MICINN Consolider-Ingenio 2010 Programme CPAN (CSD2007-00042), Comunidad de Madrid HEP-HACOS S2009/ESP-1473, Spanish MINECO's Centro de Excelencia Severo Ochoa Program (SEV-2012-0234, SEV-2012-0249), and the Juan de la Cierva Program.
Anomalous Higgs Couplings at Colliders
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.
Anomalous Hall effect in polycrystalline Ni films
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.
Anomalous Hall effect in localization regime
Wu, Lin; Zhu, Kai; Yue, Di; Tian, Yuan; Jin, Xiaofeng
2016-06-01
The anomalous Hall effect in the ultrathin film regime is investigated in Fe(001)(1-3 nm) films epitaxial on MgO(001). The logarithmic localization correction to longitudinal resistivity and anomalous Hall resistivity are observed at low temperature. We identify that the coefficient of skew scattering has a reduction from metallic to localized regime, while the contribution of side jump has inconspicuous change except for a small drop below 10 K. Furthermore, we discover that the intrinsic anomalous Hall conductivity decreases with the reduction of thickness below 2 nm. Our results provide unambiguous experimental evidence to clarify the problem of localization correction to the anomalous Hall effect.
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...
General Relativity and Gravitation
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.
Gravitational Entropy and Inflation
Directory of Open Access Journals (Sweden)
Øystein Elgarøy
2013-09-01
Full Text Available The main topic of this paper is a description of the generation of entropy at the end of the inflationary era. As a generalization of the present standard model of the Universe dominated by pressureless dust and a Lorentz invariant vacuum energy (LIVE, we first present a flat Friedmann universe model, where the dust is replaced with an ideal gas. It is shown that the pressure of the gas is inversely proportional to the fifth power of the scale factor and that the entropy in a comoving volume does not change during the expansion. We then review different measures of gravitational entropy related to the Weyl curvature conjecture and calculate the time evolution of two proposed measures of gravitational entropy in a LIVE-dominated Bianchi type I universe, and a Lemaitre-Bondi-Tolman universe with LIVE. Finally, we elaborate upon a model of energy transition from vacuum energy to radiation energy, that of Bonanno and Reuter, and calculate the time evolution of the entropies of vacuum energy and radiation energy. We also calculate the evolution of the maximal entropy according to some recipes and demonstrate how a gap between the maximal entropy and the actual entropy opens up at the end of the inflationary era.
Energy Technology Data Exchange (ETDEWEB)
Burinskii, A., E-mail: burinskii@mail.ru [Russian Academy of Sciences, Nuclear Safety Institute (Russian Federation)
2015-08-15
The Kerr–Newman (KN) black hole (BH) solution exhibits the external gravitational and electromagnetic field corresponding to that of the Dirac electron. For the large spin/mass ratio, a ≫ m, the BH loses horizons and acquires a naked singular ring creating two-sheeted topology. This space is regularized by the Higgs mechanism of symmetry breaking, leading to an extended particle that has a regular spinning core compatible with the external KN solution. We show that this core has much in common with the known MIT and SLAC bag models, but has the important advantage of being in accordance with the external gravitational and electromagnetic fields of the KN solution. A peculiar two-sheeted structure of Kerr’s gravity provides a framework for the implementation of the Higgs mechanism of symmetry breaking in configuration space in accordance with the concept of the electroweak sector of the Standard Model. Similar to other bag models, the KN bag is flexible and pliant to deformations. For parameters of a spinning electron, the bag takes the shape of a thin rotating disk of the Compton radius, with a ring–string structure and a quark-like singular pole formed at the sharp edge of this disk, indicating that the considered lepton bag forms a single bag–string–quark system.
Burinskii, A.
2015-08-01
The Kerr-Newman (KN) black hole (BH) solution exhibits the external gravitational and electromagnetic field corresponding to that of the Dirac electron. For the large spin/mass ratio, a ≫ m, the BH loses horizons and acquires a naked singular ring creating two-sheeted topology. This space is regularized by the Higgs mechanism of symmetry breaking, leading to an extended particle that has a regular spinning core compatible with the external KN solution. We show that this core has much in common with the known MIT and SLAC bag models, but has the important advantage of being in accordance with the external gravitational and electromagnetic fields of the KN solution. A peculiar two-sheeted structure of Kerr's gravity provides a framework for the implementation of the Higgs mechanism of symmetry breaking in configuration space in accordance with the concept of the electroweak sector of the Standard Model. Similar to other bag models, the KN bag is flexible and pliant to deformations. For parameters of a spinning electron, the bag takes the shape of a thin rotating disk of the Compton radius, with a ring-string structure and a quark-like singular pole formed at the sharp edge of this disk, indicating that the considered lepton bag forms a single bag-string-quark system.
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
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
Unification of Electromagnetism and Gravitation
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.
Exact piecewise flat gravitational waves
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
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)
Vignettes in Gravitation and Cosmology
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.
Gravitational Wave for a pedestrian
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.
Gravitational Repulsion and Dirac Antimatter
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.
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
Bubble collision with gravitation
Hwang, Dong-il; Lee, Wonwoo; Yeom, Dong-han
2012-01-01
In this paper, we study vacuum bubble collisions with various potentials including gravitation, assuming spherical, planar, and hyperbolic symmetry. We use numerical calculations from double-null formalism. Spherical symmetry can mimic the formation of a black hole via multiple bubble collisions. Planar and especially hyperbolic symmetry describes two bubble collisions. We study both cases, when two true vacuum regions have the same field value or different field values, by varying tensions. For the latter case, we also test symmetric and asymmetric bubble collisions, and see details of causal structures. If the colliding energy is sufficient, then the vacuum can be destabilized, and it is also demonstrated. This double-null formalism can be a complementary approach in the context of bubble collisions.
Anomalous osmosis resulting from preferential absorption
Staverman, A.J.; Kruissink, C.A.; Pals, D.T.F.
1965-01-01
An explanation of the anomalous osmosis described in the preceding paper is given in terms of friction coefficients in the glass membrane. It is shown that anomalous osmosis may be expected when the friction coefficients are constant and positive provided that the membrane absorbs solute strongly an
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
Non-Anomalous Semigroups and Real Numbers
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.
Earth Gravitational Model 2020
Barnes, D.; Factor, J. K.; Holmes, S. A.; Ingalls, S.; Presicci, M. R.; Beale, J.; Fecher, T.
2015-12-01
The National Geospatial-Intelligence Agency [NGA], in conjunction with its U.S. and international partners, has begun preliminary work on its next Earth Gravitational Model, to replace EGM2008. The new 'Earth Gravitational Model 2020' [EGM2020] has an expected public release date of 2020, and will likely retain the same harmonic basis and resolution as EGM2008. As such, EGM2020 will be essentially an ellipsoidal harmonic model up to degree (n) and order (m) 2159, but will be released as a spherical harmonic model to degree 2190 and order 2159. EGM2020 will benefit from new data sources and procedures. Updated satellite gravity information from the GOCE and GRACE mission, will better support the lower harmonics, globally. Multiple new acquisitions (terrestrial, airborne and shipborne) of gravimetric data over specific geographical areas, will provide improved global coverage and resolution over the land, as well as for coastal and some ocean areas. Ongoing accumulation of satellite altimetry data as well as improvements in the treatment of this data, will better define the marine gravity field, most notably in polar and near-coastal regions. NGA and partners are evaluating different approaches for optimally combining the new GOCE/GRACE satellite gravity models with the terrestrial data. These include the latest methods employing a full covariance adjustment. NGA is also working to assess systematically the quality of its entire gravimetry database, towards correcting biases and other egregious errors where possible, and generating improved error models that will inform the final combination with the latest satellite gravity models. Outdated data gridding procedures have been replaced with improved approaches. For EGM2020, NGA intends to extract maximum value from the proprietary data that overlaps geographically with unrestricted data, whilst also making sure to respect and honor its proprietary agreements with its data-sharing partners.
Gravitational Anomalies in the Solar System?
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...
Gravitational anomalies and one dimensional behaviour of black holes
Majhi, Bibhas Ranjan
2015-01-01
It has been pointed out by Bekenstein and Mayo that the behavior of the Black hole's entropy or information flow is similar to that through one-dimensional channel. Here I analyse the same issue with the use of gravitational anomalies. The rate of the entropy change ($\\dot{S}$) 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 $\\dot{S}$ on power is $\\dot{S}\\propto P^{1/2}$ which is identical to that for the information flow in 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 one dimensional situation, known as Pendry's formula, while in later situation its value decreases.
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
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.
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.)
Anomalous transport at weak coupling
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...
Anomalous extracellular diffusion in rat cerebellum.
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
Anomalous Growth of Aging Populations
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.
Anomalous diffraction in hyperbolic materials
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.
Weight, gravitation, inertia, and tides
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.
Supersymmetric Self-Gravitating Solitons
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.
Gravitational Wave - Gauge Field Oscillations
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.
Phonon creation by gravitational waves
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.
Gravitation. [Book on general relativity
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.
Pati, G S; Salit, M; Shahriar, M S
2006-01-01
The concept of the 'white-light cavity' has recently generated considerable research interest in the context of gravitational wave detection. Cavity designs are proposed using negative (or anomalous) dispersion in an intracavity medium to make the cavity resonate over a large range of frequencies and still maintain a high cavity build-up. This paper presents the first experimental attempt and demonstration of white-light effect in a meter long ring cavity using an intracavity atomic medium. The medium's negative dispersion is caused by bi-frequency Raman gain in an atomic vapor cell. Although the white light condition was not perfectly achieved and improvements in experimental control are still desirable, significantly broad cavity response over bandwidth greater than 20 MHz has been observed. These devices will have potential applications in new generation laser interferometer gravitational wave detectors.
Gravitation toward Walls among Human Subjects
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)
Considerations on Gravitational Wave in Economics
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.
Academic Training: Gravitational Waves Astronomy
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...
Gravitational perturbation of traversable wormhole
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.
Noiseless Gravitational Lensing Simulations
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...
Gravitational quantum cohomology
Eguchi, Tohru; Xiong, C S; Eguchi, Tohru; Hori, Kentaro; Xiong, Chuan Sheng
1996-01-01
We discuss how the theory of quantum cohomology may be generalized to ``gravitational quantum cohomology'' by studying topological sigma models coupled to two-dimensional gravity. We first consider sigma models defined on a general Fano manifold M (manifold with a positive first Chern class) and derive new recursion relations for its two point functions. We then derive bi-Hamiltonian structures of the theories and show that they are completely integrable at least at the level of genus 0. We next consider the subspace of the phase space where only a marginal perturbation (with a parameter t) is turned on and construct Lax operators (superpotentials) L whose residue integrals reproduce correlation functions. In the case of M=CP^N the Lax operator is given by L= Z_1+Z_2+\\cdots +Z_N+e^tZ_1^{-1}Z_2^{-1}\\cdots Z_N^{-1} and agrees with the potential of the affine Toda theory of the A_N type. We also obtain Lax operators for various Fano manifolds; Grassmannians, rational surfaces etc. In these examples the number of...
Gould, Andrew
2010-01-01
Thompson has recently argued that the Kozai mechanism is primarily responsible for driving white-dwarf binary mergers and so generating type Ia supernovae (SNe). If this is the case, the gravitational wave signal from these systems will be characterized by isolated repeating pulses that are well approximated by parabolic encounters. I show that standard Fourier-based searches would do a very poor job of digging these sources out of the noise, and propose a new type matched filter search, which can improve sensitivity by up to a factor ~30 relative to Fourier. If these eccentric binaries account for even a modest fraction of the observed SN rate, then there should be of order 1 pulse every 20 seconds coming from within 1 kpc, and there should be of order a thousand detectable sources in this same volume. I outline methods of identifying these sources both to remove this very pernicious background to other signals, and to find candidate SN Ia progenitors, and I sketch practical methods to find optical counterpa...
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...
Gravitational N-body Simulations
Trenti, M
2008-01-01
Gravitational N-body simulations, that is numerical solutions of the equations of motions for N particles interacting gravitationally, are widely used tools in astrophysics, with applications from few body or solar system like systems all the way up to galactic and cosmological scales. In this article we present a summary review of the field highlighting the main methods for N-body simulations and the astrophysical context in which they are usually applied.
Long pendulums in gravitational gradients
Energy Technology Data Exchange (ETDEWEB)
Suits, B H [Physics Department, Michigan Technological University, Houghton, MI 49931 (United States)
2006-03-01
Previous results for long pendulums above a spherical Earth are generalized for arbitrary non-uniform gravitational fields in the limit of small oscillation. As is the case for the previous results, gravitational gradients are multiplied by the length of the string even though the string is assumed massless. The effect is shown to arise from the constraint on the motion imposed by the string. The significance of these results for real gradients is discussed. (letters and comments)
Atom gravimeters and gravitational redshift
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.
Dark Energy, Gravitation and Electromagnetism
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.
Gravitational energy of a Schwarzschild black hole
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.
Nuclear Quantum Gravitation - The Correct Theory
Kotas, Ronald
2016-03-01
Nuclear Quantum Gravitation provides a clear, definitive Scientific explanation of Gravity and Gravitation. It is harmonious with Newtonian and Quantum Mechanics, and with distinct Scientific Logic. Nuclear Quantum Gravitation has 10 certain, Scientific proofs and 21 more good indications. With this theory the Physical Forces are obviously Unified. See: OBSCURANTISM ON EINSTEIN GRAVITATION? http://www.santilli- Foundation.org/inconsistencies-gravitation.php and Einstein's Theory of Relativity versus Classical Mechanics http://www.newtonphysics.on.ca/einstein/
Guerras, Eduardo; Steele, Shaun; Liu, Ang; Kochanek, Christopher S; Chartas, George; Morgan, Christopher W; Chen, Bin
2016-01-01
We present an X-ray photometric analysis of six gravitationally lensed quasars spanning from 5 to 14 years, measuring the total (0.83-21.8 keV restframe), soft (0.83-3.6 keV), and hard (3.6-21.8 keV) band image flux ratios for each epoch. Using the ratios of the model-predicted macro-magnifications as baselines, we build differential microlensing curves and obtain joint likelihood functions for the average X-ray emission region sizes. Our analysis yields a Probability Distribution Function for the average half-light radius of the X-Ray emission region in the sample that peaks slightly above 1 gravitational radius, and yields nearly indistinguishable 68 % confidence (one-sided) upper limits of 17.8 (18.9) gravitational radii for the soft (hard) X-ray emitting region, assuming a mean stellar mass of 0.3 solar masses. We see hints of energy dependent microlensing between the soft and hard bands in two of the objects. In a separate analysis on the root-mean-square (RMS) of the microlensing variability, we find si...
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.
The charmonium dissociation in an "anomalous wind"
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.
Anomalous Fractional Diffusion Equation for Transport Phenomena
Institute of Scientific and Technical Information of China (English)
QiuhuaZENG; HouqiangLI; 等
1999-01-01
We derive the standard diffusion equation from the continuity equation and by discussing the defectiveness of earlier proposed equations,we get the generalized fractional diffusion equation for anomalous diffusion.
On gravitational-electromagnetic resonance
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.
Gravitational Effects on Signal Transduction
Sytkowski, Arthur J.
1999-01-01
An understanding of the mechanisms by which individual cells perceive gravity and how these cells transduce and respond to gravitational stimuli is critical for the development of long-term manned space flight experiments. We now propose to use a well-characterized model erythroid cell system and to investigate gravitational perturbations of its erythropoietin (Epo) signaling pathway and gene regulation. Cells will be grown at 1-G and in simulated microgravity in the NASA Rotating Wall Vessel bioreactor (RWV). Cell growth and differentiation, the Epo-receptor, the protein kinase C pathway to the c-myc gene, and the protein phosphatase pathway to the c-myb gene will be studied and evaluated as reporters of gravitational stimuli. The results of these experiments will have impact on the problems of 1) gravitational sensing by individual cells, and 2) the anemia of space flight. This ground-based study also will serve as a Space Station Development Study in gravitational effects on intracellular signal transduction.
Gravitational Collapse of Gravitational Waves in 3D Numerical Relativity
Alcubierre, M; Brügmann, B; Lanfermann, G; Seidel, E; Suen, W M; Tobias, M; Alcubierre, Miguel; Allen, Gabrielle; Bruegmann, Bernd; Lanfermann, Gerd; Seidel, Edward; Suen, Wai-Mo; Tobias, Malcolm
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 {\\it and} non-axisymmetric Brill waves, including waves so strong that they collapse to form black holes under their own self-gravity. The critical amplitude for black hole formation is determined. The gravitational waves emitted in the black hole formation process are compared to those emitted in the head-on collision of two Misner black holes.
Spin gravitational resonance and graviton detection
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.
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.
Gravitational Origin of Dark Matter
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...
Thought Experiments on Gravitational Forces
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...
Gravitational waves and multimessenger astronomy
Ricci, Fulvio
2016-07-01
It is widely expected that in the coming quinquennium the first gravitational wave signal will be directly detected. The ground-based advanced LIGO and Virgo detectors are being upgraded to a sensitivity level such that we expect to be measure a significant binary merger rate. Gravitational waves events are likely to be accompanied by electromagnetic counterparts and neutrino emission carrying complementary information to those associated to the gravitational signals. If it becomes possible to measure all these forms of radiation in concert, we will end up an impressive increase in the comprehension of the whole phenomenon. In the following we summarize the scientific outcome of the interferometric detectors in the past configuration. Then we focus on some of the potentialities of the advanced detectors once used in the new context of the multimessenger astronomy.
Gravitational baryogenesis after anisotropic inflation
Fukushima, Mitsuhiro; Mizuno, Shuntaro; Maeda, Kei-ichi
2016-05-01
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.
Gravitational Instabilities in Circumstellar Disks
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...
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.
Gravitational Baryogenesis after Anisotropic Inflation
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.
Gravitational Lensing - Einstein's Unfinished Symphony
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...
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.
Zitterbewegung and gravitational Berry phase
Energy Technology Data Exchange (ETDEWEB)
Papini, Giorgio, E-mail: papini@uregina.ca [Department of Physics and Prairie Particle Physics Institute, University of Regina, Regina, Sask S4S 0A2 (Canada); International Institute for Advanced Scientific Studies, 89019 Vietri sul Mare (Italy)
2012-03-12
Berry phases mix states of positive and negative energy in the propagation of fermions and bosons in external gravitational and electromagnetic fields and generate Zitterbewegung oscillations. The results are valid in any reference frame and to any order of approximation in the metric deviation. -- Highlights: ► Berry phases generate Zitterbewegung oscillations in the propagation of particles. ► The covariant approach applies to gravitational and electromagnetic fields. ► The curvature of space–time affects Hilbert space via Berry phases. ► Berry phases mix the positive and negative energy states of relativistic particles.
General relativity and gravitational waves
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
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.
Quantum gravitational effects on boundary
Park, I Y
2016-01-01
Quantum gravitational effects may hold the key to some of the outstanding problems in theoretical physics. In this work we analyze the perturbative quantum effects on the boundary of a gravitational system and Dirichlet boundary condtion imposed at the classical level. Our analysis reveals that for a black hole solution there exists a clash between the quantum effects and Dirichlet boundary condition: the solution of the one-particle-irreducible (1PI) action no longer obeys the Dirichlet boundary condition. The analysis also suggests that the violation of the Dirichlet boundary condition should be tied with a certain mechanism of information storage on the boundary.
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.
Gravitational waves carrying orbital angular momentum
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.
Gravitating BPS dyons witout a dilaton
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.
Gravitational waves carrying orbital angular momentum
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.
The Japanese space gravitational wave antenna - DECIGO
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...
Precursory singularities in spherical gravitational collapse
Lake, Kayll
1992-05-01
General conditions are developed for the formation of naked precursory ('shell-focusing') singularities in spherical gravitational collapse. These singularities owe their nakedness to the fact that the gravitational potential fails to be single valued prior to the onset of a true gravitational singularity. It is argued that they do not violate the spirit of cosmic censorship. Rather, they may well be an essentially generic feature of relativistic gravitational collapse.
Astrometric and timing effects of gravitational waves
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...
Gravitational Waves in Effective Quantum Gravity
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...
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.
How to test gravitation theories by means of gravitational-wave measurements
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.
Theory of the Muon Anomalous Magnetic Moment
Melnikov, Kirill
2006-01-01
The theory of the muon anomalous magnetic moment is "particle physics in a nutshell" and as such is interesting, exciting and difficult. The current precision of the experimental value for this quantity, improved significantly in the past several years due to experiment E821 at Brookhaven National Laboratory, is so high that a large number of subtle effects not relevant previously, become important for the interpretation of the experimental result. The theory of the muon anomalous magnetic moment is at the cutting edge of current research in particle physics and includes multiloop calculations in both QED and electroweak theory, precision low-energy hadron physics, isospin violations and scattering of light by light. Any deviation between the theoretical prediction and the experimental value might be interpreted as a signal of an as-yet-unknown new physics. This book provides a comprehensive review of the theory of the muon anomalous magnetic moment.
Anomalous fluorescence line intensity in megavoltage bremsstrahlung
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.
Soft-/rapidity- anomalous dimensions correspondence
Vladimirov, Alexey A
2016-01-01
We establish a correspondence between ultraviolet singularities of soft factors for multi-particle production and rapidity singularities of soft factors for multi-parton scattering. This correspondence is a consequence of a conformal mapping between scattering geometries. The correspondence is valid to all orders of perturbation theory and in this way provides a proof of rapidity renormalization procedure for multi-parton scattering soft factors (including the transverse momentum dependent (TMD) soft factor as a special case). As a by-product we obtain an exact relation between the rapidity anomalous dimension and the well-known soft anomalous dimension. The three-loop rapidity anomalous dimensions for TMD and a general multi-parton scattering are derived.
Electroweak Baryogenesis with Anomalous Higgs Couplings
Kobakhidze, Archil; Yue, Jason
2015-01-01
We investigate feasibility of efficient baryogenesis at the electroweak scale within the effective field theory framework based on a non-linear realisation of the electroweak gauge symmetry. In this framework the LHC Higgs boson is described by a singlet scalar field, which, therefore, admits new interactions. Assuming that Higgs couplings with the eletroweak gauge bosons are as in the Standard Model, we demonstrate that the Higgs cubic coupling and the CP-violating Higgs-top quark anomalous couplings alone may drive the a strongly first-order phase transition. The distinguished feature of this transition is that the anomalous Higgs vacuum expectation value is generally non-zero in both phases. We identify a range of anomalous couplings, consistent with current experimental data, where sphaleron rates are sufficiently fast in the 'symmetric' phase and are suppressed in the 'broken' phase and demonstrate that the desired baryon asymmetry can indeed be generated in this framework. This range of the Higgs anomal...
Anomalous magnetohydrodynamics in the extreme relativistic domain
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...
Academic Training: Gravitational Waves Astronomy
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...
Scaling Laws in Gravitational Collapse
Cai, Rong-Gen
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.
Zitterbewegung and gravitational Berry phase
Papini, Giorgio
2012-01-01
Berry phases mix states of positive and negative energy in the propagation of fermions and bosons in external gravitational and electromagnetic fields and generate Zitterbewegung oscillations. The results are valid in any reference frame and to any order of approximation in the metric deviation.
Gravitational Laser Back-Scattering
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.
MACROSCOPIC ROTORS AND GRAVITATIONAL EFFECTS
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.
Gravitational Lensing: Einstein's unfinished symphony
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.
Cosmological Acceleration from Gravitational Waves
Marochnik, Leonid
2015-01-01
It is shown that the classical gravitational waves of super-horizon wavelengths are able to form the de Sitter accelerated expansion of the empty (with no matter fields) Universe. The contemporary Universe is about 70% empty and asymptotically is going to become completely empty, so the effect caused by emptiness should be already very noticeable. It could manifest itself as the dark energy.
Counteracting Gravitation In Dielectric Liquids
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.
Folding Gravitational-Wave Interferometers
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.
Detecting gravitational waves from accreting neutron stars
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
Gravitational Binding Energy in Charged Cylindrical Symmetry
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.
The damping of gravitational waves in dust
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.
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.
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.
Unification of Gravitation and Gauge Fields
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.
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
Anomalous Feeding of the Left Upper Lobe.
Hazzard, Christopher; Itagaki, Shinobu; Lajam, Fouad; Flores, Raja M
2016-09-01
We report the case of a 53-year-old woman who presented with massive hemoptysis. Computed tomographic angiography revealed an anomalous vessel arising from the abdominal aorta, coursing anteriorly and through the diaphragm, and feeding the left upper lobe. At operation the vessel was found to anastomose to the left upper lobe lingula, which contained multiple vascular abnormalities and arteriovenous fistulas. The vessel was ligated, and the affected portion of the left upper lobe was resected. Anomalous systemic arterial supply of an upper lobe is an especially rare form of a Pryce type 1 abnormality. Recognition of these unusual anatomic variants is crucial to successful treatment and avoidance of adverse events.
Anomalous Diffusion on the Percolating Networks
Institute of Scientific and Technical Information of China (English)
DeLIU; HouqiangLI; 等
1997-01-01
According to the standard diffusion equation,by introducing reasonably into a anomalous diffusion coefficient,the generalized diffusion equation,which describes anomalous diffusion on the percolating networks with a power-law distribution of waiting times,is derived in this paper.The solution of the generalized diffusion equation is obtained by using the method,which is used by Barta,The problems of anomaloous diffusion on percolating networks with a power-law distribution of waiting times,which aren't solved by Barta,are resolved.
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.
[Anomalous systemic arterial supply to left basal lung with anomalous return of V6].
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
The Japanese space gravitational wave antenna - DECIGO
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.
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.
Gravitational Waves in Effective Quantum Gravity
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.
Gravitational Waves in Effective Quantum Gravity
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.
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
Spherical gravitational curvature boundary-value problem
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.
Anomalous Hall Effect for chiral fermions
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.
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.
Anomalous Couplings in W Pair Production
Biebel, J
1998-01-01
I present a short overview over W pair production and studies of angular differential cross-sections with and without initial state radiation applying semi-analytical methods and using the Fortran program GENTLE. The influence of anomalous couplings to this process is also discussed.
Anomalous human behavior detection: An Adaptive approach
Leeuwen, C. van; Halma, A.; Schutte, K.
2013-01-01
Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous b
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.)
STIS MAMA Recovery from Anomalous Shutdown
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.
Anomalous N = 2 superconformal Ward identities
Ketov, S V
2000-01-01
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 te...
Anomalous atomic volume of alpha-Pu
DEFF Research Database (Denmark)
Kollar, J.; Vitos, Levente; Skriver, Hans Lomholt
1997-01-01
.3%. The comparison between the LDA and GGA results show that the anomalously large atomic volume of alpha-Pu relative to alpha-Np can be ascribed to exchange-correlation effects connected with the presence of low coordinated sites in the structure where the f electrons are close to the onset of localization...
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
Gravitating multidefects from higher dimensions
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.
The Loudest Gravitational Wave Events
Chen, Hsin-Yu
2014-01-01
We derive the universal distribution of signal-to-noise ratios for gravitational wave detection. Because gravitational waves (GWs) are almost impossible to obscure via dust absorption or other astrophysical processes, the strength of the detected signal is dictated solely by the emission strength and the distance to the source. Assuming that the space density of an arbitrary population of GW sources does not evolve, the distribution of detected signal-to-noise (SNR) values depends solely on the detection threshold; it is independent of the detector network (interferometer or pulsar timing array), the individual detector noise curves (initial or Advanced LIGO), the nature of the GW sources (compact binary coalescence, supernova, or some other discrete source), and the distributions of source variables such as the binary masses and spins (only non-spinning neutron stars of mass exactly $1.4\\,M_\\odot$ or a complicated distribution of masses and spins). We also derive the SNR distribution for each individual dete...
Gravitational wave science from space
Gair, Jonathan R.
2016-05-01
The rich millihertz gravitational wave band can only be accessed with a space- based detector. The technology for such a detector will be demonstrated by the LISA Pathfinder satellite that is due to launch this year and ESA has selected gravitational wave detection from space as the science theme to be addressed by the L3 large mission to be launched around 2034. In this article we will discuss the sources that such an instrument will observe, and how the numbers of events and precision of parameter determination are affected by modifications to the, as yet not finalised, mission design. We will also describe some of the exciting scientific applications of these observations, to astrophysics, fundamental physics and cosmology.
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.
Conformal gravity and "gravitational bubbles"
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...
Nonadiabatic charged spherical gravitational collapse
Di Prisco, A; Denmat, G Le; MacCallum, M A H; Santos, N O
2007-01-01
We present a complete set of the equations and matching conditions required for the description of physically meaningful charged, dissipative, spherically symmetric gravitational collapse with shear. Dissipation is described with both free-streaming and diffusion approximations. The effects of viscosity are also taken into account. The roles of different terms in the dynamical equation are analyzed in detail. The dynamical equation is coupled to a causal transport equation in the context of Israel-Stewart theory. The decrease of the inertial mass density of the fluid, by a factor which depends on its internal thermodynamic state, is reobtained, with the viscosity terms included. In accordance with the equivalence principle, the same decrease factor is obtained for the gravitational force term. The effect of the electric charge on the relation between the Weyl tensor and the inhomogeneity of energy density is discussed.
Classifying self-gravitating radiations
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.
Loop Quantum Cosmology Gravitational Baryogenesis
Odintsov, S D
2016-01-01
Loop Quantum Cosmology is an appealing quantum completion of classical cosmology, which brings along various theoretical features which in many cases offer remedy or modify various classical cosmology aspects. In this paper we address the gravitational baryogenesis mechanism in the context of Loop Quantum Cosmology. As we demonstrate, when Loop Quantum Cosmology effects are taken into account in the resulting Friedmann equations for a flat Friedmann-Robertson-Walker Universe, then even for a radiation dominated Universe, the predicted baryon-to-entropy ratio from the gravitational baryogenesis mechanism is non-zero, in contrast to the Einstein-Hilbert case, in which case the baryon-to-entropy ratio is zero. We also discuss various other cases apart from the radiation domination case, and we discuss how the baryon-to-entropy ratio is affected from the parameters of the quantum theory. In addition, we use illustrative exact solutions of Loop Quantum Cosmology and we investigate under which circumstances the bar...
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.
A gravitating electroweak bag model
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.
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.
Open problems in gravitational physics
Capozziello, S
2014-01-01
We discuss some fundamental issues underlying gravitational physics and point out some of the main shortcomings of Einstein's General Relativity. In particular, after taking into account the role of the two main objects of relativistic theories of gravity, i.e. the metric and the connection fields, we consider the possibility that they are not trivially related so that the geodesic structure and the causal structure of the spacetime could be disentangled, as supposed in the Palatini formulation of gravity. In this perspective, the Equivalence Principle, in its weak and strong formulations, can play a fundamental role in discriminating among competing theories. The possibility of its violation at quantum level could open new perspectives in gravitational physics and in unification with other interactions. We shortly debate the possibility of equivalence principle measurements by ground-based and space experiments.
Thermal Duality and Gravitational Collapse
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...
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.
Progress towards Gravitational Wave Astronomy
Papa, M Alessandra
2008-01-01
I will review the most recent and interesting results from gravitational wave detection experiments, concentrating on recent results from the LIGO Scientific Collaboration (LSC). I will outline the methodologies utilized in the searches, explain what can be said in the case of a null result, what quantities may be constrained. I will compare these results with prior expectations and discuss their significance. As I go along I will outline the prospects for future improvements.
Pulsars revived by gravitational waves
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.
Gravitational Instabilities in Circumstellar Disks
Kratter, Kaitlin; Lodato, Giuseppe
2016-09-01
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 nonlinear 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 analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular
Cylindrical Collapse and Gravitational Waves
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.
Gravitational Global Monopoles with Horizons
Maison, D
1999-01-01
We give arguments for the existence of ``radial excitations'' of gravitational global monopoles with any number of zeros of the Higgs field and present numerical results for solutions with up to two zeros. All these solutions possess a de Sitter like cosmological horizon, outside of which they become singular. In addition we study corresponding static ``hairy'' black hole solutions, representing black holes sitting inside a global monopole core. In particular, we determine their existence domains as a function of their horizon radius rh.
Mansouri-Chang gravitation theory
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.
Gravitating Dyons in Vaidya Geometry
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.
Towards an Alternative Gravitational Theory
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...
Anomalous Fluctuations in Observations of Q0957+561 A,B: Smoking Gun of a Cosmic String?
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.
Measuring Gravitation Using Polarization Spectroscopy
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.
Study of Gravitational Lens Chromaticity from Ground-based Narrow Band Photometry
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...
Gravitational Lensing: Strong, Weak and Micro
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 ...
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.
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.
The Early Universe Odyssey With Gravitational Waves
Grishchuk, L P
2002-01-01
This contribution summarizes some recent work on gravitational-wave astronomy and, especially, on the generation and detection of relic gravitational waves. We begin with a brief discussion of astrophysical sources of gravitational waves that are likely to be detected first by the coming in operation laser interferometers, such as GEO, LIGO, VIRGO. Then, we proceed to relic gravitational waves emphasizing their quantum-mechanical origin and the inevitability of their existence. Combining the theory with available observations, we discuss the prospects of direct detection of relic gravitational waves. A considerable part of the paper is devoted to comparison of relic gravitational waves with the density perturbations of quantum-mechanical origin. It is shown how the phenomenon of squeezing of quantum-mechanically generated cosmological perturbations manifests itself in the periodic structures of the metric power spectra and in the oscillatory behaviour of the CMBR multipoles $C_l$ as a function of $l$. The cos...
Universal Gravitation as Lorentz-covariant Dynamics
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...
Petrology of Anomalous Eucrite QUE 94484
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.
Remote sensing and characterization of anomalous debris
Sridharan, R.; Beavers, W.; Lambour, R.; Gaposchkin, E. M.; Kansky, J.; Stansbery, E.
1997-01-01
The analysis of orbital debris data shows a band of anomalously high debris concentration in the altitude range between 800 and 1000 km. Analysis indicates that the origin is the leaking coolant fluid from nuclear power sources that powered a now defunct Soviet space-based series of ocean surveillance satellites. A project carried out to detect, track and characterize a sample of the anomalous debris is reported. The nature of the size and shape of the sample set, and the possibility of inferring the composition of the droplets were assessed. The technique used to detect, track and characterize the sample set is described and the results of the characterization analysis are presented. It is concluded that the nature of the debris is consistent with leaked Na-K fluid, although this cannot be proved with the remote sensing techniques used.
Anomalous Coronary Artery: Run of a Lifetime.
Green, Michael Stuart; Sehgal, Sankalp; Smukler, Naomi; Suber, LaDouglas Jarod; Saththasivam, Pooven
2016-09-01
The anatomy of the coronary circulation is well described with incidence of congenital anomalies of approximately 0.3% to 1.0%. Although often incidental, 20% are life-threatening. A 25-year-old woman with syncopal episodes collapsed following a 10-km run. Coronary anatomy evaluation showed an anomalous left main coronary artery originating from the right sinus of valsalva and following a course between the aorta and the pulmonary outflow tract. Percutaneous coronary intervention was followed by eventual surgical revascularization. Abnormal course of coronary arteries plays a role in the pathogenesis of sudden death on exertion. Origin of the left main coronary from the right sinus of valsalva is a rare congenital anomaly. The expansion of the roots of the aorta and pulmonary trunk with exertion lead to compression of the coronary artery and syncope. Our patient raises awareness of a potentially fatal coronary artery path. Intraoperative identification of anomalous coronaries by utilizing intraoperative transesophageal echocardiography was critical.
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....
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.
Anomalous Hall effect in Weyl superconductors
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.
Gravitational Couplings on D-brane Revisited
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.
Response of massive bodies to gravitational waves
Hannibal, L; Hannibal, Ludger; Warkall, Jens
2000-01-01
The repsonse of a massive body to gravitational waves is decribed on the microscopic level, taking the metric perturbations of the electromagnetic and gravitational forces into account. The effects found substantially differ from those obtained in the commonly used oscillator model. The electromagnetic coupling induces a dominant surface effect, the gravitational coupling gives rise to the excitation of quadrupole modes, but several oredes of magnitude smaller.
Einstein and Gravitational Waves 1936-1938
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!
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.
Electromagnetic Effects in Superconductors in Gravitational Field
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...
Classical Underpinnings of Gravitationally Induced Quantum Interference
Mannheim, P D
1996-01-01
We show that the gravitational modification of the phase of a neutron beam (the COW experiment) has a classical origin, being due to the time delay which classical particles experience in traversing a background gravitational field. Similarly, we show that classical light waves also undergo a phase shift in traversing a gravitational field. We show that the COW experiment respects the equivalence principle even in the presence of quantum mechanics.
Electroweak Baryogenesis with Anomalous Higgs Couplings
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.
Anomalous velocity distributions in active Brownian suspensions
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...
Anomalous diffusions induced by enhancement of memory
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...
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.
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...... 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....
Anomalous water drop bouncing on a nanotextured surface by the Leidenfrost levitation
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.
The Anomalous Magnetic Moment of the Muon
Jegerlehner, Friedrich
2008-01-01
This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. The muon anomalous magnetic moment amy is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. A major part of the book is devoted to the theory of the anomalous magnetic moment and to estimates of the theoretical uncertainties. Quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. After the overview of theory, the exper...
Anomalous diffusion induced by enhancement of memory
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.
Anomalous dominance, immune parameters, and spatial ability.
Hassler, M
1993-02-01
In a sample of male and female subjects in late adolescence, we investigated the relationship of spatial abilities to anomalous dominance and immune parameters as suggested by Geschwind's model of cerebral lateralization (Geschwind & Galaburda, 1985) In addition to the behavioral markers asthma/allergies, migraine, and myopia, we measured IgE and Ig total in blood serum. Atypical handedness, atypical language dominance, and atypical visuospatial dominance were found to be connected with spatial giftedness, and atypical handedness was related to immune vulnerability in males. This outcome provided some support for the Geschwind model in men. In women, spatial giftedness was related to immune vulnerability, but no indicator of anomalous dominance was connected with either giftedness, or immune parameters. Thus, the central thesis of the Geschwind model, i.e., elevated prenatal testosterone effects on the developing brain cause anomalous dominance and, as side effects, spatial giftedness and immune vulnerability, and all these consequences should be related to each other, was not confirmed by our data for females.
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.
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.
Gravitation: Global Formulation and Quantum Effects
Aldrovandi, R; Vu, K H
2004-01-01
A nonintegrable phase-factor global approach to gravitation is developed by using the similarity of teleparallel gravity with electromagnetism. The phase shifts of both the COW and the gravitational Aharonov-Bohm effects are obtained. It is then shown, by considering a simple slit experiment, that in the classical limit the global approach yields the same result as the gravitational Lorentz force equation of teleparallel gravity. It represents, therefore, the quantum mechanical version of the classical description provided by the gravitational Lorentz force equation. As teleparallel gravity can be formulated independently of the equivalence principle, it will consequently require no generalization of this principle at the quantum level.
Astrophysical Gravitational Wave Sources Literature Catalog
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...
Gravitational Wave Astrophysics: Opening the New Frontier
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.
Gravitational wave radiometry: Mapping a stochastic gravitational wave background
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...
Gravitational entropy of cosmic expansion
Sussman, Roberto A
2014-01-01
We apply a recent proposal to define "gravitational entropy" to the expansion of cosmic voids within the framework of non-perturbative General Relativity. By considering CDM void configurations compatible with basic observational constraints, we show that this entropy grows from post-inflationary conditions towards a final asymptotic value in a late time fully non-linear regime described by the Lemaitre-Tolman-Bondi (LTB) dust models. A qualitatively analogous behavior occurs if we assume a positive cosmological constant consistent with a $\\Lambda$-CDM background model. However, the $\\Lambda$ term introduces a significant suppression of entropy growth with the terminal equilibrium value reached at a much faster rate.
Gravitational drainage of foam films.
Sett, S; Sinha-Ray, S; Yarin, A L
2013-04-23
Gravitational drainage from thick plane vertical soap films and hemispherical bubbles is studied experimentally and theoretically. The experiments involve microinterferometry kindred to the one used in the experiments in the Scheludko cell. The following surfactants were used in the experiments: cationic dodecyltrimethylammonium bromide (DTAB), anionic sodium dodecyl sulfate (SDS), anionic Pantene shampoo which primarily contains sodium lauryl sulfate, nonionic tetraethylene glycol monooctyl ether (C8E4), and nonionic Pluronic (P-123) surfactants at different concentrations. The theoretical results explain the drainage mechanism and are used to develop a new method of measurement of the surface elasticity and to test it on the above-mentioned surfactants. PMID:23557027
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.
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.
The Scales of Gravitational Lensing
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.
The Future of Gravitational Optics
Blandford, R D
2001-01-01
In this speculative, millenial essay, I try to anticipate what sort of novel gravitational optics investigations might be observed, after it becomes possible to map and monitor roughly a trillion sources (of which a billion may be usefully variable) comprehensively throughout electromagnetic and other spectra over the whole sky. Existing techniques suffice to produce three dimensional maps of the dark matter distribution of the accessible universe, to explore black hole spacetimes and to magnify images of the first luminous sources, terrestrial planets and compact objects.
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.
$f(T)$ gravitational baryogenesis
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.
Matrix Models and Gravitational Corrections
Dijkgraaf, R; Temurhan, M; Dijkgraaf, Robbert; Sinkovics, Annamaria; Temurhan, Mine
2002-01-01
We provide evidence of the relation between supersymmetric gauge theories and matrix models beyond the planar limit. We compute gravitational R^2 couplings in gauge theories perturbatively, by summing genus one matrix model diagrams. These diagrams give the leading 1/N^2 corrections in the large N limit of the matrix model and can be related to twist field correlators in a collective conformal field theory. In the case of softly broken SU(N) N=2 super Yang-Mills theories, we find that these exact solutions of the matrix models agree with results obtained by topological field theory methods.
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.
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.
Omnidirectional Gravitational Wave Detector with a Laser-Interferometric Gravitational Compass
Maia, M D; Sousa, Claudio M G; Magalhaes, Nadja S; Frajuca, Carlos
2016-01-01
Based on the Szekeres-Pirani gravitational compass we suggest the addition of a fourth, non-coplanar mass/mirror to the presently existing laser based gravitational wave observatories, enabling them to operate omnidirectionally, to filter out ambiguous interpretations and to point out the direction of the gravitational wave source.
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.
Probing a Gravitational Cat State
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...
Quasar evolution and gravitational collapse
Energy Technology Data Exchange (ETDEWEB)
Cavaliere, A.; Giallongo, E.; Vagnetti, F.; Messina, A.
1983-06-01
The paper presents three convergent results concerning the sources in theactive nuclei of quasars and radio galaxies that derive their power fromconversion of gravitational energy. We first derive, for several leading modelsbased on liberation of gravitational energy from mass in a compact supply, thelaws governing the secular change L of the primary power driving the individual sources, and identify their common and key property: L increases, and eventually decreases, linearly or faster with the power itself, so that the associated time scales t/sub s/ = L/Vertical BarLVertical Bar obey dt/sub s/, (L)/dL<0. We then describe a general statistical framework to populate with sources the (luminosity, cosmic time)-plane, based on a continuity equation that embodies a given L. We show how the main features of the populations depend primarily on L, while the memory of the initial details is easily erased. With L as derived above, we obtain basic evolutions of the density (L>0) and of the luminosity (L<0) type, with a global differential character. Finally we compute the full evolution functions, comprising a brightening (L>0) and a dimming (L<0) phase, corresponding to three such models. Sub-Eddington accretion onto a massive black hole from a star cluster that self-destroys by collisions is close to reproduce the general course of the empirical models for the optical QSO population.
Confusion in Cosmology and Gravitation
Corda, C.; Katebi, R.; Schmidt, N. O.
2016-06-01
In a series of papers, Santilli and collaborators released various strong statements against the general theory of relativity (GTR) and the standard ΛCDM model of cosmology. In this paper we show that such claims are due to misunderstandings of basic concepts of gravitation and cosmology. In particular, we show that Santilli and collaborators demonstrated neither that the GTR is wrong, nor that the Universe is not expanding. We also show that the so-called iso-gravitation theory (IGT) of Santilli is in macroscopic contrast with geodesic motion and, in turn, with the Equivalence Principle (EP) and must therefore be ultimately rejected. Finally, we show that, although the so called iso-redshift could represent an interesting alternative (similar to the tired light theory historically proposed by Zwicky) to the Universe expansion from a qualitative point of view, it must be rejected from a quantitative point of view because the effect of iso-redshift is 10-6 smaller than the effect requested to achieve the cosmological redshift.
Confusion in Cosmology and Gravitation
Corda, C.; Katebi, R.; Schmidt, N. O.
2016-10-01
In a series of papers, Santilli and collaborators released various strong statements against the general theory of relativity (GTR) and the standard ΛCDM model of cosmology. In this paper we show that such claims are due to misunderstandings of basic concepts of gravitation and cosmology. In particular, we show that Santilli and collaborators demonstrated neither that the GTR is wrong, nor that the Universe is not expanding. We also show that the so-called iso-gravitation theory (IGT) of Santilli is in macroscopic contrast with geodesic motion and, in turn, with the Equivalence Principle (EP) and must therefore be ultimately rejected. Finally, we show that, although the so called iso-redshift could represent an interesting alternative (similar to the tired light theory historically proposed by Zwicky) to the Universe expansion from a qualitative point of view, it must be rejected from a quantitative point of view because the effect of iso-redshift is 10-6 smaller than the effect requested to achieve the cosmological redshift.
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.
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.
A report on the gravitational redshift test for non-metric theories of gravitation
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%.
Testing Gravitational Physics with Space-based Gravitational-wave Observations
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.
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.)
A discerning gravitational property for gravitational equation in higher dimensions
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.
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.)
Gravitational waves from accreting neutron stars
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}.
Gravitational radiation from a rotating magnetic dipole
Hacyan, Shahen
2016-01-01
The gravitational radiation emitted by a rotating magnetic dipole is calculated. Formulas for the polarization amplitudes and the radiated power are obtained in closed forms, considering both the near and radiation zones of the dipole. For a neutron star, a comparison is made with other sources of gravitational and electromagnetic radiation.
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.
Articulated Multimedia Physics, Lesson 9, Universal Gravitation.
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…
Cosmological meaning of the gravitational gauge group
Lu, Jia-An
2014-01-01
It is shown that under a Kaluza--Klein-like ansatz, the de Sitter group as the gravitational gauge group can choose the only one model that may avert the big-bang singularity by torsion under certain assumptions, in a class of gravitational models with quadratic torsion terms.
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)
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.)
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.
Axially symmetric SU(3) Gravitating Skyrmions
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.
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
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
Probing Cosmic Superstrings with Gravitational Waves
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...
Gravitational Interactions and Fine-Structure Constant
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.
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
Optics in a nonlinear gravitational wave
Harte, Abraham I
2015-01-01
Gravitational waves can act like gravitational lenses, affecting the observed positions, brightnesses, and redshifts of distant objects. Exact expressions for such effects are derived here, allowing for arbitrarily-moving sources and observers in the presence of plane-symmetric gravitational waves. The commonly-used predictions of linear perturbation theory are shown to be generically overshadowed---even for very weak gravitational waves---by nonlinear effects when considering observations of sufficiently distant sources; higher-order perturbative corrections involve secularly-growing terms which cannot necessarily be neglected. Even on more moderate scales where linear effects remain at least marginally dominant, nonlinear corrections are qualitatively different from their linear counterparts. There is a sense in which they can, for example, mimic the existence of a third type of gravitational wave polarization.
Optics in a nonlinear gravitational plane wave
Harte, Abraham I.
2015-09-01
Gravitational waves can act like gravitational lenses, affecting the observed positions, brightnesses, and redshifts of distant objects. Exact expressions for such effects are derived here in general relativity, allowing for arbitrarily-moving sources and observers in the presence of plane-symmetric gravitational waves. At least for freely falling sources and observers, it is shown that the commonly-used predictions of linear perturbation theory can be generically overshadowed by nonlinear effects; even for very weak gravitational waves, higher-order perturbative corrections involve secularly-growing terms which cannot necessarily be neglected when considering observations of sufficiently distant sources. Even on more moderate scales where linear effects remain at least marginally dominant, nonlinear corrections are qualitatively different from their linear counterparts. There is a sense in which they can, for example, mimic the existence of a third type of gravitational wave polarization.
Gravitational wave signal from massive gravity
Gumrukcuoglu, A Emir; Lin, Chunshan; Mukohyama, Shinji; Tanahashi, Norihiro
2012-01-01
We discuss the detectability of gravitational waves with a time dependent mass contribution, by means of the stochastic gravitational wave observations. Such a mass term typically arises in the cosmological solutions of massive gravity theories. We conduct the analysis based on a general quadratic action, and thus the results apply universally to any massive gravity theories in which modification of general relativity appears primarily in the tensor modes. The primary manifestation of the modification in the gravitational wave spectrum is a sharp peak. The position and height of the peak carry information on the present value of the mass term, as well as the duration of the inflationary stage. We also discuss the detectability of such a gravitational wave signal using the future-planned gravitational wave observatories.
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...
The conceptual origins of gravitational lensing
Valls-Gabaud, David
2012-01-01
We critically examine the evidence available of the early ideas on the bending of light due to a gravitational attraction, which led to the concept of gravitational lenses, and attempt to present an undistorted historical perspective. Contrary to a widespread but baseless claim, Newton was not the precursor to the idea, and the first Query in his {\\sl Opticks} is totally unrelated to this phenomenon. We briefly review the roles of Voltaire, Marat, Cavendish, Soldner and Einstein in their attempts to quantify the gravitational deflection of light. The first, but unpublished, calculations of the lensing effect produced by this deflection are found in Einstein's 1912 notebooks, where he derived the lensing equation and the formation of images in a gravitational lens. The brief 1924 paper by Chwolson which presents, without calculations, the formation of double images and rings by a gravitational lens passed mostly unnoticed. The unjustly forgotten and true pioneer of the subject is F. Link, who not only publishe...
Local gravitational redshifts can bias cosmological measurements
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...
Cosmological applications of strong gravitational lensing
DEFF Research Database (Denmark)
Paraficz, Danuta
value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown....... The first Chapter presents a historical background of gravitational lensing. It explains the process involved in creating the theory of gravitational lenses. It shows how Newton and then Einstein developed the concept and how Refsdal and others made it a cosmological tool. We present in more detail how...... gravitational lensing influenced the history of physics by being the first proof of Einstein's theory of gravity. The Chapter ends by discussing the first observational discovery of a strong gravitational lens....
Comparing numerical and analytic approximate gravitational waveforms
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.
Localization corrections to the anomalous Hall effect in a ferromagnet
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...
Anomalous Josephson Hall effect in magnet/triplet superconductor junctions
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...
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)
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.
Anomalous Hall Effect in a Kagome Ferromagnet
Ye, Linda; Wicker, Christina; Suzuki, Takehito; Checkelsky, Joseph; Joseph Checkelsky Team
The ferromagnetic kagome lattice is theoretically known to possess topological band structures. We have synthesized large single crystals of a kagome ferromagnet Fe3Sn2 which orders ferromagnetically well above room temperature. We have studied the electrical and magnetic properties of these crystals over a broad temperature and magnetic field range. Both the scaling relation of anomalous Hall effect and anisotropic magnetic susceptibility show that the ferromagnetism of Fe3Sn2 is unconventional. We discuss these results in the context of magnetism in kagome systems and relevance to the predicted topological properties in this class of compounds. This research is supported by DMR-1231319.
Anomalous Redshift of Some Galactic Objects
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]).
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
Anomalous mapping between pionfull and pionless EFT's
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...
Anomalous Diffusion on the Hanoi Networks
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...
On the photon anomalous magnetic moment
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.
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
Kofinas, Georgios
2013-01-01
We raise on theoretical grounds the question of the physical relevance of Israel matching conditions and their generalizations to higher codimensions, the standard cornerstone of the braneworld and other membrane scenarios. Our reasoning is twofold: First, the incapability of the conventional matching conditions to accept the Nambu-Goto probe limit (even the geodesic limit of the Israel matching conditions is not acceptable since being the geodesic equation a kinematical fact it should be preserved for all gravitational theories or defects, which is not the case for these conditions). Second, in our D-dimensional spacetime (maybe D=4), classical defects of any possible codimension should be compatible. These matching conditions fail to accept codimension-2 and 3 defects for D=4 (which represents effectively the spacetime at certain length and energy scales) and most probably fail to accept high enough codimensional defects for any D since there is no high enough Lovelock density to support them. Here, we prop...
Gravitational action with null boundaries
Lehner, Luis; Poisson, Eric; Sorkin, Rafael D
2016-01-01
We present a complete discussion of the boundary term in the action functional of general relativity when the boundary includes null segments in addition to the more usual timelike and spacelike segments. We confirm that ambiguities appear in the contribution from a null segment, because it depends on an arbitrary choice of parametrization for the generators. We also show that similar ambiguities appear in the contribution from a codimension-two surface at which a null segment is joined to another (spacelike, timelike, or null) segment. The parametrization ambiguity can be tamed by insisting that the null generators be affinely parametrized; this forces each null contribution to the boundary action to vanish, but leaves intact the fredom to rescale the affine parameter by a constant factor on each generator. Once a choice of parametrization is made, the ambiguity in the joint contributions can be eliminated by formulating well-motivated rules that ensure the additivity of the gravitational action. Enforcing t...
Consequences of gravitational radiation recoil
Merritt, D; Favata, M; Hughes, S A; Holz, D E; Merritt, David; Milosavljevic, Milos; Favata, Marc; Hughes, Scott A.; Holz, Daniel E.
2004-01-01
Coalescing binary black holes experience an impulsive kick due to anisotropic emission of gravitational waves. We discuss the dynamical consequences of the recoil accompanying massive black hole mergers. Recoil velocities are sufficient to eject most coalescing black holes from dwarf galaxies and globular clusters, which may explain the apparent absence of massive black holes in these systems. Ejection from giant elliptical galaxies would be rare, but coalescing black holes are displaced from the center and fall back on a time scale of order the crossing time. Displacement of the black holes transfers energy to the stars in the nucleus and can convert a steep density cusp into a core. Radiation recoil calls into question models that grow supermassive black holes from hierarchical mergers of stellar-mass precursors.
Gauss-Bonnet gravitational baryogenesis
Odintsov, S. D.; Oikonomou, V. K.
2016-09-01
In this letter we study some variant forms of gravitational baryogenesis by using higher order terms containing the partial derivative of the Gauss-Bonnet scalar coupled to the baryonic current. This scenario extends the well known theory that uses a similar coupling between the Ricci scalar and the baryonic current. One appealing feature of the scenario we study is that the predicted baryon asymmetry during a radiation domination era is non-zero. We calculate the baryon to entropy ratio for the Gauss-Bonnet term and by using the observational constraints we investigate which are the allowed forms of the R + F (G) gravity controlling the evolution. Also we briefly discuss some alternative higher order terms that can generate a non-zero baryon asymmetry, even in the conformal invariance limit.
Gravitation, Causality, and Quantum Consistency
Hertzberg, Mark P
2016-01-01
We examine the role of consistency with causality and quantum mechanics in determining the properties of gravitation. We begin by constructing two different classes of interacting theories of massless spin 2 particles -- gravitons. One involves coupling the graviton with the lowest number of derivatives to matter, the other involves coupling the graviton with higher derivatives to matter, making use of the linearized Riemann tensor. The first class requires an infinite tower of terms for consistency, which is known to lead uniquely to general relativity. The second class only requires a finite number of terms for consistency, which appears as a new class of theories of massless spin 2. We recap the causal consistency of general relativity and show how this fails in the second class for the special case of coupling to photons, exploiting related calculations in the literature. In an upcoming publication [1] this result is generalized to a much broader set of theories. Then, as a causal modification of general ...
Inflation with large gravitational waves
Vikman, A
2006-01-01
It is well known that in manifestly Lorentz invariant theories with nontrivial kinetic terms, perturbations around some classical backgrounds can travel faster than light. These exotic "supersonic" models may have interesting consequences for cosmology and astrophysics. In particular, one can show that in such theories the contribution of the gravitational waves to the CMB fluctuations can be significantly larger than that in standard inflationary models. This increase of the tensor-to-scalar perturbation ratio leads to a larger B-component of the CMB polarization, thus making the prospects for future detection much more promising. Interestingly, the spectral index of scalar perturbations and mass of the scalar field considered in the model are practically indistinguishable from the standard case. Whereas the energy scale of inflation and hence the reheating temperature can be much higher compared to a simple chaotic inflation.
Horizon Thermodynamics and Gravitational Tension
Widom, A; 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 terms of the conventional Einstein general theory of relativity that apparently does explain much and maybe all of presently known experimental gravity data. The central result is that matter on the horizon surface is bound by the entropy-area law by tension in the closely analogous sense that the Wilson action-area law also describes a surface confinement.
Three hundred years of gravitation
Hawking, Stephen William
1987-01-01
To commemorate the 300th anniversary of the publication of Isaac Newton's Philosophiae Naturalis Principia Mathematica, Stephen Hawking and Werner Israel have assembled a series of unique review papers by many of the world's foremost researchers in cosmology, relativity and particle physics. The resulting volume reflects the significant and exciting advances that have been made in these fields since the editor's acclaimed volume published in 1979: General Relativity: An Einstein Centenary Survey. Newton's immense contribution to the physical sciences is assessed, and its relevance to today's physics made clear. The international contributors then chart the major developments in the study of gravitation, from Newtonian gravity to black hole physics. In the fields of galaxy formation, inflationary and quantum cosmology, and superstring unification, the book provides important overviews written by workers involved in many of the advances described. By shaping such a wide-ranging and scholarly series of articles ...
Diffraction Anomalous Near-Edge Structure
Moltaji, Habib O., Jr.
1995-11-01
To determine the atomic structure about atom of an element in a sample of a condensed multicomponent single crystal, contrast radiation is proposed with the use of Diffraction Anomalous Near-Edge Structure (DANES), which combines the long-range order sensitivity of the x-ray diffraction and short-range order of the x-ray absorption near-edge techniques. This is achieved by modulating the photon energy of the x-ray beam incident on the sample over a range of energies near an absorption edge of the selected element. Due to anomalous dispersion, x-ray diffraction, and x-ray absorption, the DANES intensity with respect to the selected element is obtained in a single experiment. I demonstrate that synchrotron DANES measurements for the single crystal of thin film and the powder samples and provide the same local atomic structural information as the x-ray absorption near-edge with diffraction condition and can be used to provide enhanced site selectivity. I demonstrate calculations of DAFS intensity and measurements of polarized DANES and XANES intensity.
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.
Macromolecular structure phasing by neutron anomalous diffraction.
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
Top polarisation measurement and anomalous $Wtb$ coupling
Prasath, Arun; Rindani, Saurabh D
2014-01-01
Kinematical distributions of the decay products of the top quark carry information on the polarisation of the top as well as on any possible new physics in the decay of the top quark. We construct observables in the form of asymmetries in the kinematical distributions to probe their effects. Charged-lepton angular distributions in the decay are insensitive to anomalous couplings and are a sensitive measure of top polarisation. However, these are difficult to measure in the case of highly boosted top quarks as compared to energy distributions of decay products. These are then sensitive, in general, to both top polarisation and top anomalous couplings. We compare various asymmetries for their sensitivities to the polarisation of the top quark as well as to possible new physics in the $Wtb$ vertex, paying special attention to the case of highly boosted top quarks. We perform a $\\chi ^2$- analysis to determine the regions in the polarisation of the top quark and the couplings of the $Wtb$ vertex constrained by di...
Anomalous superfluid density in quantum critical superconductors
Hashimoto, Kenichiro; Mizukami, Yuta; Katsumata, Ryo; Shishido, Hiroaki; Yamashita, Minoru; Ikeda, Hiroaki; Matsuda, Yuji; Schlueter, John A.; Fletcher, Jonathan D.; Carrington, Antony; Gnida, Daniel; Kaczorowski, Dariusz; Shibauchi, Takasada
2013-01-01
When a second-order magnetic phase transition is tuned to zero temperature by a nonthermal parameter, quantum fluctuations are critically enhanced, often leading to the emergence of unconventional superconductivity. In these “quantum critical” superconductors it has been widely reported that the normal-state properties above the superconducting transition temperature Tc often exhibit anomalous non-Fermi liquid behaviors and enhanced electron correlations. However, the effect of these strong critical fluctuations on the superconducting condensate below Tc is less well established. Here we report measurements of the magnetic penetration depth in heavy-fermion, iron-pnictide, and organic superconductors located close to antiferromagnetic quantum critical points, showing that the superfluid density in these nodal superconductors universally exhibits, unlike the expected T-linear dependence, an anomalous 3/2 power-law temperature dependence over a wide temperature range. We propose that this noninteger power law can be explained if a strong renormalization of effective Fermi velocity due to quantum fluctuations occurs only for momenta k close to the nodes in the superconducting energy gap Δ(k). We suggest that such “nodal criticality” may have an impact on low-energy properties of quantum critical superconductors. PMID:23404698
Gravitational Redshifts in Simulated Galaxy Clusters
Kim, Y R; Kim, Young-Rae; Croft, Rupert
2004-01-01
We predict the amplitude of the gravitational redshift of galaxies in galaxy clusters using an N-body simulation of a Lambda CDM universe. We examine if it might be possible to detect the gravitational effect on the total redshift observed for galaxies. For clusters of mass M ~10^15 m_sun, the difference in gravitational redshift between the brightest galaxy and the rest of the cluster members is ~10 km/s. The most efficient way to detect gravitational redshifts using information from galaxies only involves using the full gravitational redshift profile of clusters. Massive clusters, while having the largest gravitational redshift suffer from large galaxy peculiar velocities and substructure, which act as a source of noise. This and their low number density make it more reasonable to try averaging over many clusters and groups of relatively low mass. We examine publicly available data for 107 rich clusters from the ESO Nearby Abell Clusters Survey (ENACS), finding no evidence for gravitational redshifts. Test ...
Gravitating sphalerons in the Skyrme model
Shnir, Ya
2015-01-01
We construct self-gravitating axially symmetric sphaleron solutions of the 3+1 dimensional Skyrme model coupled to Einstein gravity. The solutions are static and asymptotically flat, they are characterized by two integers n and m, where n is the winding numbers of the constituents and the second integer m defines type of the solution. These configuration correspond to the chains of charge n Skyrmions and charge -n anti-Skyrmions placed along the axis of symmetry in alternating order. We investigate the dependency of the masses of the gravitating sphalerons on the gravitational coupling. We find new chains of self-gravitating |n| = 1 Skyrmions-anti-Skyrmions (S-A) which emerge at some critical non-zero value of the gravitational coupling and do not have flat space limit. In contrast, the branches of self-gravitating |n| $\\ge$ 2 S-A chains emerge from the corresponding flat space configurations. In both cases these branches merge at some maximal value of the effective gravitational coupling the branches of diff...
Generalized gravitational entropy from total derivative action
Dong, Xi; Miao, Rong-Xin
2015-12-01
We investigate the generalized gravitational entropy from total derivative terms in the gravitational action. Following the method of Lewkowycz and Maldacena, we find that the generalized gravitational entropy from total derivatives vanishes. We compare our results with the work of Astaneh, Patrushev, and Solodukhin. We find that if total derivatives produced nonzero entropy, the holographic and the field-theoretic universal terms of entanglement entropy would not match. Furthermore, the second law of thermodynamics could be violated if the entropy of total derivatives did not vanish.
The Japanese space gravitational wave antenna; DECIGO
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, K.-s.; 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. DECIGO is expected to open a new window of observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries of the universe such as dark energy, formation mechanism of supermassive black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of three drag-free spacecraft, whose relative displacements are measured by a differential Fabry-Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre-DECIGO first and finally DECIGO in 2024.
Gravitational waves from scalar field accretion
Núnez, Darío; Degollado, Juan Carlos; Moreno, Claudia
2011-01-01
Our aim in this work is to outline some physical consequences of the interaction between black holes and scalar field halos in terms of gravitational waves. In doing so, the black hole is taken as a static and spherically symmetric gravitational source, {\\it i. e.} the Schwarzschild black hole, and we work within the test field approximation, considering that the scalar field lives in the curved space-time outside the black hole. We focused on the emission of gravitational waves when the blac...
Generalized Gravitational Entropy from Total Derivative Action
Dong, Xi
2015-01-01
We investigate the generalized gravitational entropy from total derivative terms in the gravitational action. Following the method of Lewkowycz and Maldacena, we find that the generalized gravitational entropy from total derivatives vanishes. We compare our results with the work of Astaneh, Patrushev, and Solodukhin. We find that if total derivatives produced nonzero entropy, the holographic and the field-theoretic universal terms of entanglement entropy would not match. Furthermore, the second law of thermodynamics could be violated if the entropy of total derivatives did not vanish.
A Gravitational Edge Detection for Multispectral Images
Directory of Open Access Journals (Sweden)
Genyun Sun
2013-07-01
Full Text Available Gravitational edge detection is one of the new edge detection algorithms that is based on the law of gravity. This algorithm assumes that each image pixel is a celestial body with a mass represented by its grayscale intensity and their interactions are based on the Newtonian laws of gravity. In this article, a multispectral version of the algorithm is introduced. The method uses gravitational techniques in combination with metric tensor to detect edges of multispectral images including color images. To evaluate the performances of the proposed algorithm, several experiments are performed. The experimental results confirm the efficiency of the multispectral gravitational edge detection.
Electromagnetic Effects in Superconductors in Gravitational Field
Ahmedov, B J
2005-01-01
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 gravity. A magnetic flux (being proportional to angular velocity of rotation $\\Omega$) through a rotating hollow superconducting cylinder with the radial gradient of temperature $\
Gravitational waves in geometric scalar gravity
Toniato, J D
2016-01-01
We investigate the description of gravitational waves in the geometric scalar theory of gravity (GSG). The GSG belongs to a class of theories such that gravity is described by a single scalar field and the associated physical metric describing the spacetime is constructed from a disformal transformation of Minkowski geometry. In this theory, gravitational waves have a longitudinal polarization mode, besides others modes that are observer dependent. We examine the orbital variation of a binary system due to the emission of gravitational waves, showing that GSG can also be successful in explaining this phenomena.
Newtorites in bar detectors of gravitational wave
Ronga, F
2015-01-01
The detection of particles with only gravitational interactions (Newtorites) in gravitational bar detectors was studied in 1984 by Bernard, De Rujula and Lautrup. The negative results of dark matter searches suggest to look to exotic possibilities like Newtorites. The limits obtained with the Nautilus bar detector will be presented and the possible improvements will be discussed. Since the gravitational coupling is very weak, the possible limits are very far from what is needed for dark matter, but for large masses are the best limits obtained on the Earth. An update of limits for MACRO particles will be given.
Gravitational brainwaves, quantum fluctuations and stochastic quantization
Bar, D
2007-01-01
It is known that the biological activity of the brain involves radiation of electric waves. These waves result from ionic currents and charges traveling among the brain's neurons. But it is obvious that these ions and charges are carried by their relevant masses which should give rise, according to the gravitational theory, to extremely weak gravitational waves. We use in the following the stochastic quantization (SQ) theory to calculate the probability to find a large ensemble of brains radiating similar gravitational waves. We also use this SQ theory to derive the equilibrium state related to the known Lamb shift.
Chiral Gravitational Waves from Chiral Fermions
Anber, Mohamed M
2016-01-01
We report on a new mechanism that leads to the generation of primordial chiral gravitational waves, and hence, the violation of the parity symmetry in the Universe. We show that nonperturbative production of fermions with a definite helicity is accompanied by the generation of chiral gravitational waves. This is a generic and model-independent phenomenon that can occur during inflation, reheating and radiation eras, and can leave imprints in the cosmic microwave background polarization and may be observed in future ground- and space-based interferometers. We also discuss a specific model where chiral gravitational waves are generated via the production of light chiral fermions during pseudoscalar inflation.
The theory of space, time and gravitation
Fock, V
2015-01-01
The Theory of Space, Time, and Gravitation, 2nd Revised Edition focuses on Relativity Theory and Einstein's Theory of Gravitation and correction of the misinterpretation of the Einsteinian Gravitation Theory. The book first offers information on the theory of relativity and the theory of relativity in tensor form. Discussions focus on comparison of distances and lengths in moving reference frames; comparison of time differences in moving reference frames; position of a body in space at a given instant in a fixed reference frame; and proof of the linearity of the transformation linking two iner
Gravitational Waves from Collapsing Vacuum Domains
Gleiser, Marcello; Gleiser, Marcelo; Roberts, Ronald
1998-01-01
The breaking of an approximate discrete symmetry, the final stages of a first order phase transition, or a post-inflationary biased probability distribution for scalar fields are possible cosmological scenarios characterized by the presence of unstable domain wall networks. Combining analytical and numerical techniques, we show that the non-spherical collapse of these domains can be a powerful source of gravitational waves. We compute their contribution to the stochastic background of gravitational radiation and explore their observability by present and future gravitational wave detectors.
Hypermass generalization of Einstein's gravitation theory
Edmonds, J. D., Jr.
1973-01-01
The curvilinear invariant quaternion formalism is examined for curved space time. Einstein's gravitation equation is shown to have a simple and natural form in this notation. The hypermass generalization of particle mass, which was generated in our studies of the Dirac equation, is incorporated in gravitation by generalizing Einstein's equation. Covariance requires that the gravitational constant be generalized to an invariant quaternion when the mass is. The modification appears minor and of no importance cosmologically, unless one begins considering time and mass dependence of G.
Neutrino oscillations in strong gravitational fields
Roy, M F; Roy, Mou; Wudka, Jose
1996-01-01
Neutrino oscillations in the presence of strong gravitational fields are studied. We look at very high energy neutrinos (\\sim 1 TeV) emanating from Active Galactic Nuclei (AGN). It is observed that spin flavor resonant transitions of such neutrinos may occur in the vicinity of AGN due to {\\it gravitational} effects and due to the presence of a large magnetic field (\\sim 1 Tesla). A point to note is that matter effects (normal MSW transitions) become negligible in comparison o gravitational effects in our scenario.
Gravitational radiation in dynamical noncommutative spaces
Alavi, S A
2015-01-01
The gravitational radiation in dynamical non-commutative spaces (DNCS) is explored. we derive the corrections due to dynamical noncommutativity on the gravitational potential. We obtain the DNC corrections on the angular velocity as well as the radiated power of the system. By calculating the period decay of the system and using the observational data we obtain an upper bound for the DNS parameter {\\tau} . We also study quantum interference induced by gravitational potential in usual non-commutative and dynamical non-commutative spaces. The phase difference induced by gravity is calculated on two different paths and then, it is compared with the phase difference induced by gravity in commutative space.
Non-Euclidean Geometry and Gravitation
Directory of Open Access Journals (Sweden)
Stavroulakis N.
2006-04-01
Full Text Available A great deal of misunderstandings and mathematical errors are involved in the currently accepted theory of the gravitational field generated by an isotropic spherical mass. The purpose of the present paper is to provide a short account of the rigorous mathematical theory and exhibit a new formulation of the problem. The solution of the corresponding equations of gravitation points out several new and unusual features of the stationary gravitational field which are related to the non-Euclidean structure of the space. Moreover it precludes the black hole from being a mathematical and physical notion.
The Gravitational Wave International Committee Roadmap: The future of gravitational wave astronomy
,
2011-01-01
Gravitational wave science is on the verge of direct observation of the waves predicted by Einstein's General Theory of Relativity and opening the exciting new field of gravitational wave astronomy. In the coming decades, ultra-sensitive arrays of ground-based instruments and complementary spaced-based instruments will observe the gravitational wave sky, inevitably discovering entirely unexpected phenomena while providing new insight into many of the most profound astrophysical phenomena known. in July 2007 the Gravitational Wave International Committee (GWIC) initiated the development of a strategic roadmap for the field of gravitational wave science with a 30-year horizon. The goal of this roadmap is to serve the international gravitational wave community and its stakeholders as a tool for the development of capabilities and facilities needed to address the exciting scientific opportunities on the intermediate and long-term horizons.
An algorithm for DLP on anomalous elliptic curves over Fp
Institute of Scientific and Technical Information of China (English)
祝跃飞; 裴定一
2002-01-01
This paper improves the method of discrete logarithm on anomalous elliptic curves, and establishes an isomorphism from E(Fp) to Fp which can be more easily implemented. Fruthermore, we give an optimized algorithm for discrete logarithm on anomalous elliptic curves E(Fp).
Bootstrapping Rapidity Anomalous Dimension for Transverse-Momentum Resummation
Energy Technology Data Exchange (ETDEWEB)
Li, Ye [Fermilab; Zhu, Hua Xing [MIT, Cambridge, CTP
2016-04-05
Soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders are computed through to three loops in the expansion of strong coupling, with the help of bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.
Anomalous Hall Effect in non-commutative mechanics
Horvathy, P. A.
2006-01-01
The anomalous velocity term in the semiclassical model of a Bloch electron deviates the trajectory from the conventional one. When the Berry curvature (alias noncommutative parameter) is a monopole in momentum space as found recently in some ferromagnetic semiconductors while observing the anomalous Hall effect, we get a transverse shift, similar to that in the optical Hall effect.
Bootstrapping rapidity anomalous dimension for transverse-momentum resummation
Li, Ye
2016-01-01
Soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders are computed through to three loops in the expansion of strong coupling, with the help of bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.
Weinstein, Galina
2012-01-01
In December 1911, Max Abraham published a paper on gravitation at the basis of which was Albert Einstein's 1911 June conclusion about a relationship between the velocity of light and the gravitational potential. In February 1912, Einstein published his work on static gravitational fields, which was based on his 1911 June theory. In March 1912, Einstein corrected his paper, but Abraham claimed that Einstein borrowed his equations; however, it was actually Abraham who needed Einstein's ideas an...
Anomalous Evidence, Confidence Change, and Theory Change.
Hemmerich, Joshua A; Van Voorhis, Kellie; Wiley, Jennifer
2016-08-01
A novel experimental paradigm that measured theory change and confidence in participants' theories was used in three experiments to test the effects of anomalous evidence. Experiment 1 varied the amount of anomalous evidence to see if "dose size" made incremental changes in confidence toward theory change. Experiment 2 varied whether anomalous evidence was convergent (of multiple types) or replicating (similar finding repeated). Experiment 3 varied whether participants were provided with an alternative theory that explained the anomalous evidence. All experiments showed that participants' confidence changes were commensurate with the amount of anomalous evidence presented, and that larger decreases in confidence predicted theory changes. Convergent evidence and the presentation of an alternative theory led to larger confidence change. Convergent evidence also caused more theory changes. Even when people do not change theories, factors pertinent to the evidence and alternative theories decrease their confidence in their current theory and move them incrementally closer to theory change.
Thermal gravitational waves in accelerating universe
Directory of Open Access Journals (Sweden)
B Ghayour
2013-10-01
Full Text Available 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 current accelerating phase of the universe. The enhancement feature of amplitude and spectral energy density of the waves is independent of the expansion model of the universe and hence the thermal effect accounts for it. Therefore, existence of thermal gravitational waves is not ruled out
Gravitational Waves and Time Domain Astronomy
Centrella, Joan; Nissanke, Samaya; Williams, Roy
2012-01-01
The gravitational wave window onto the universe will open in roughly five years, when Advanced LIGO and Virgo achieve the first detections of high frequency gravitational waves, most likely coming from compact binary mergers. Electromagnetic follow-up of these triggers, using radio, optical, and high energy telescopes, promises exciting opportunities in multi-messenger time domain astronomy. In the decade, space-based observations of low frequency gravitational waves from massive black hole mergers, and their electromagnetic counterparts, will open up further vistas for discovery. This two-part workshop featured brief presentations and stimulating discussions on the challenges and opportunities presented by gravitational wave astronomy. Highlights from the workshop, with the emphasis on strategies for electromagnetic follow-up, are presented in this report.
Exploring Higher-Order Gravitational Waves
Arcos, H; Pereira, J G
2015-01-01
In addition to the usual linear gravitational waves in transverse-traceless coordinates, higher-order gravitational field equations, as well as their corresponding solutions, are explicitly obtained. It is found that higher-order waves do not represent corrections to the first-order wave. In contrast, all higher than second-order solutions do represent corrections to the second-order wave, a property that makes the first-order gravitational wave to stand apart from higher-order waves. Furthermore, although the first-order solution is transverse and traceless, all higher-order solutions are not. As a consequence, the whole solution is neither transverse nor traceless, a result that could eventually have important consequences for quantum gravity, and in particular for the definition of graviton itself. Some additional properties and features of these higher-order gravitational waves are explored and discussed.
Environmental Effects for Gravitational-wave Astrophysics
Barausse, Enrico; Pani, Paolo
2014-01-01
The upcoming detection of gravitational waves by terrestrial interferometers will usher in the era of gravitational-wave astronomy. This will be particularly true when space-based detectors will come of age and measure the mass and spin of massive black holes with exquisite precision and up to very high redshifts, thus allowing for better understanding of the symbiotic evolution of black holes with galaxies, and for high-precision tests of General Relativity in strong-field, highly-dynamical regimes. Such ambitious goals require that astrophysical environmental pollution of gravitational-wave signals be constrained to negligible levels, so that neither detection nor estimation of the source parameters are significantly affected. Here, we consider the main sources for space-based detectors -the inspiral, merger and ringdown of massive black-hole binaries and extreme mass-ratio inspirals- and account for various effects on their gravitational waveforms, including electromagnetic fields, cosmological evolution, ...
Update on gravitational-wave research
Grishchuk, L P
2003-01-01
The recently assembled laser-beam detectors of gravitational waves are approaching the planned level of sensitivity. In the coming 1 - 2 years, we may be observing the rare but powerful events of inspiral and merger of binary stellar-mass black holes. More likely, we will have to wait for a few years longer, until the advanced detectors become operational. Their sensitivity will be sufficient to meet the most cautious evaluations of the strength and event rates of astrophysical sources of gravitational waves. The experimental and theoretical work related to the space-based laser-beam detectors is also actively pursued. The current gravitational wave research is broad and interesting. Experimental innovations, source modelling, methods of data analysis, theoretical issues of principle are being studied and developed at the same time. The race for direct detection of relatively high-frequency waves is accompanied by vigorous efforts to discover the very low-frequency relic gravitational waves through the measur...
Gravitational waves from oscillons after inflation
Antusch, Stefan; Orani, Stefano
2016-01-01
We investigate the production of gravitational waves during preheating after inflation in the common case of field potentials that are asymmetric around the minimum. In particular, we study the impact of oscillons, comparatively long lived and spatially localized regions where a scalar field (e.g. the inflaton) oscillates with large amplitude. Contrary to a previous study, which considered a symmetric potential, we find that oscillons in asymmetric potentials associated with a phase transition can generate a pronounced peak in the spectrum of gravitational waves, that largely exceeds the linear preheating spectrum. We discuss the possible implications of this enhanced amplitude of gravitational waves. For instance, for low scale inflation models, the contribution from the oscillons can strongly enhance the observation prospects at current and future gravitational wave detectors.
Testing the Gravitational Redshift with Atomic Gravimeters?
Wolf, Peter; Bordé, Christian J; Reynaud, Serge; Salomon, Christophe; Cohen-Tannoudji, Claude
2011-01-01
Atom interferometers allow the measurement of the acceleration of freely falling atoms with respect to an experimental platform at rest on Earth's surface. Such experiments have been used to test the universality of free fall by comparing the acceleration of the atoms to that of a classical freely falling object. In a recent paper, M\\"uller, Peters and Chu [Nature {\\bf 463}, 926-929 (2010)] argued that atom interferometers also provide a very accurate test of the gravitational redshift (or universality of clock rates). Considering the atom as a clock operating at the Compton frequency associated with the rest mass, they claimed that the interferometer measures the gravitational redshift between the atom-clocks in the two paths of the interferometer at different values of gravitational potentials. In the present paper we analyze this claim in the frame of general relativity and of different alternative theories, and conclude that the interpretation of atom interferometers as testing the gravitational redshift ...
Some Remarks on Gravitational Global Monopoles
Maison, D; Maison, Dieter; Liebling, Steven L.
1999-01-01
Using mainly analytical arguments, we derive the exact relation static gravitational global monopoles. For this value, the global monopole bifurcates with the de Sitter solution obtained for vanishing Higgs field. In addition, we analyze the stability properties of the solutions.
A Reconciliation of Electromagnetism and Gravitation
Sidharth, B. G.
2001-01-01
It is argued that once we consider the underpinning of a Non Commutative geometry, itself symptomatic of extended particles, for example in Quantum Superstring theory, then a reconciliation between gravitation and electromagnetism is possible.
Gravitation and quantummechanical localization of macroobjects
Diósi, L
2015-01-01
We propose nonlinear Schr\\"odinger equation with gravitational self-interacting term. The separability conditions of Bialynicki-Birula are satisfied in asymptotic sense. Solitonlike solutions were found.
Sources of Gravitational Waves: Theory and Observations
Buonanno, Alessandra
2014-01-01
Gravitational-wave astronomy will soon become a new tool for observing the Universe. Detecting and interpreting gravitational waves will require deep theoretical insights into astronomical sources. The past three decades have seen remarkable progress in analytical and numerical computations of the source dynamics, development of search algorithms and analysis of data from detectors with unprecedented sensitivity. This Chapter is devoted to examine the advances and future challenges in understanding the dynamics of binary and isolated compact-object systems, expected cosmological sources, their amplitudes and rates, and highlights of results from gravitational-wave observations. All of this is a testament to the readiness of the community to open a new window for observing the cosmos, a century after gravitational waves were first predicted by Albert Einstein.
Spinor Formulations for Gravitational Energy-Momentum
Chen, C M; Tung, R S; Chen, Chiang-Mei; Nester, James M.; Tung, Roh-Suan
2004-01-01
We first describe a class of spinor-curvature identities (SCI) which have gravitational applications. Then we sketch the topic of gravitational energy-momentum, its connection with Hamiltonian boundary terms and the issues of positivity and (quasi)localization. Using certain SCIs several spinor expressions for the Hamiltonian have been constructed. One SCI leads to the celebrated Witten positive energy proof and the Dougan-Mason quasilocalization. We found two other SCIs which give alternate positive energy proofs and quasilocalizations. In each case the spinor field has a different role. These neat expressions for gravitational energy-momentum have much appeal. However it seems that such spinor formulations just have no room for angular momentum; which leads us to doubt that spinor formulations can really correctly capture the elusive gravitational energy-momentum.
The Rotational and Gravitational Effect of Earthquakes
Gross, Richard
2000-01-01
The static displacement field generated by an earthquake has the effect of rearranging the Earth's mass distribution and will consequently cause the Earth's rotation and gravitational field to change. Although the coseismic effect of earthquakes on the Earth's rotation and gravitational field have been modeled in the past, no unambiguous observations of this effect have yet been made. However, the Gravity Recovery And Climate Experiment (GRACE) satellite, which is scheduled to be launched in 2001, will measure time variations of the Earth's gravitational field to high degree and order with unprecedented accuracy. In this presentation, the modeled coseismic effect of earthquakes upon the Earth's gravitational field to degree and order 100 will be computed and compared to the expected accuracy of the GRACE measurements. In addition, the modeled second degree changes, corresponding to changes in the Earth's rotation, will be compared to length-of-day and polar motion excitation observations.
Geometrical vs wave optics under gravitational waves
Angélil, Raymond
2015-01-01
We present some new derivations of the effect of a plane gravitational wave on a light ray. A simple interpretation of the results is that a gravitational wave causes a phase modulation of electromagnetic waves. We arrive at this picture from two contrasting directions, namely null geodesics and Maxwell's equations, or, geometric and wave optics. Under geometric optics, we express the geodesic equations in Hamiltonian form and solve perturbatively for the effect of gravitational waves. We find that the well-known time-delay formula for light generalizes trivially to massive particles. We also recover, by way of a Hamilton-Jacobi equation, the phase modulation obtained under wave optics. Turning then to wave optics, rather than solving Maxwell's equations directly for the fields, as in most previous approaches, we derive a perturbed wave equation (perturbed by the gravitational wave) for the electromagnetic four-potential. From this wave equation it follows that the four-potential and the electric and magnetic...
Homogeneous cosmological models in Yang's gravitation theory
Fennelly, A. J.; Pavelle, R.
1979-01-01
We present a dynamic, spatially homogeneous solution of Yang's pure space gravitational field equations which is non-Einsteinian. The predictions of this cosmological model seem to be at variance with observations.
Hunting for Dark Particles with Gravitational Waves
Giudice, Gian F; Urbano, Alfredo
2016-01-01
The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking's area theorem.
Gravitational wave astronomy: the current status
Blair, David; Zhao, Chunnong; Wen, Linqing; Chu, Qi; Fang, Qi; Cai, RongGen; Gao, JiangRui; Lin, XueChun; Liu, Dong; Wu, Ling-An; Zhu, ZongHong; Reitze, David H; Arai, Koji; Zhang, Fan; Flaminio, Raffaele; Zhu, Xingjiang; Hobbs, George; Manchester, Richard N; Shannon, Ryan M; Baccigalupi, Carlo; Xu, Peng; Bian, Xing; Cao, Zhoujian; Chang, ZiJing; Dong, Peng; Gong, XueFei; Huang, ShuangLin; Ju, Peng; Luo, ZiRen; Qiang, Li'E; Tang, WenLin; Wan, XiaoYun; Wang, Yue; Xu, ShengNian; Zhang, YunLong; Zhang, HaiPeng; Lau, Yun-Kau; Ni, Wei-Tou
2016-01-01
In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan, which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravit...
The Bianchi identity and weak gravitational lensing
Energy Technology Data Exchange (ETDEWEB)
Kling, Thomas P; Keith, Brian [Department of Physics, Bridgewater State College, Bridgewater, MA 02325 (United States)
2005-07-21
We consider the Bianchi identity as a field equation for the distortion of the shapes of images produced by weak gravitational lensing. Using the spin coefficient formalism of Newman and Penrose (1962 J. Math. Phys. 3 566-78), we show that certain complex components of the Weyl and Ricci curvature tensors are directly related to fundamental observables in weak gravitational lensing. In the case of weak gravitational fields, we then show that the Bianchi identity provides a field equation for the Ricci tensor assuming a known Weyl tensor. From the Bianchi identity, we derive the integral equation for weak lensing presented by Miralda-Escude (1996 IAU Symp. vol 173 p 131), thus making the Bianchi identity a first principles equation of weak gravitational lensing. This equation is integrated in the important case of an axially symmetric lens and explicitly demonstrated in the case of a point lens and a singular isothermal sphere (SIS) model.
Cosmological inference using gravitational wave observations alone
Del Pozzo, Walter; Messenger, Chris
2015-01-01
Gravitational waves emitted during the coalescence of binary neutron star systems are self-calibrating signals. As such they can provide a direct measurement of the luminosity distance to a source without the need for a cosmic distance scale ladder. In general, however, the corresponding redshift measurement needs to be obtained electromagnetically since it is totally degenerate with the total mass of the system. Nevertheless, recent Fisher matrix studies has shown that if information about the equation of state of the neutron stars is available, it is indeed possible to extract redshift information from the gravitational wave signal alone. Therefore, measuring the cosmological parameters in pure gravitational wave fashion is possible. Furthermore, the huge number of sources potentially observable by the Einstein Telescope has led to speculations that the gravitational wave measurement is potentially competitive with traditional methods. The Einstein telescope is a conceptual study for a third generation grav...
Gravitational spectra from direct measurements
Wagner, C. A.; Colombo, O. L.
1978-01-01
A simple rapid method is described for determining the spectrum of a surface field from harmonic analysis of direct measurements along great circle arcs. The method is shown to give excellent overall trends to very high degree from even a few short arcs of satellite data. Three examples are taken with perfect measurements of satellite tracking over a planet made up of hundreds of point-masses using (1) altimetric heights from a low orbiting spacecraft, (2) velocity residuals between a low and a high satellite in circular orbits, and (3) range-rate data between a station at infinity and a satellite in highly eccentric orbit. In particular, the smoothed spectrum of the Earth's gravitational field is determined to about degree 400(50 km half wavelength) from 1 D x 1 D gravimetry and the equivalent of 11 revolutions of Geos 3 and Skylab altimetry. This measurement shows there is about 46 cm of geoid height remaining in the field beyond degree 180.
The Gravitational Wave Detector EXPLORER
2002-01-01
%RE5 EXPLORER is a cryogenic resonant-mass gravitational wave (GW) detector. It is in operation at CERN since 1984 and it has been the first cryogenic GW antenna to perform continuous observations (since 1990).\\\\ \\\\EXPLORER is actually part of the international network of resonant-mass detectors which includes ALLEGRO at the Louisiana State University, AURIGA at the INFN Legnaro Laboratories, NAUTILUS at the INFN Frascati Laboratories and NIOBE at the University of Western Australia. The EXPLORER sensitivity, at present of the same order of the other antennas, is 10$^{-20}$ Hz$^{-1/2}$ over a bandwidth of 20 Hz and 6 10$^{-22}$ Hz$^{-1/2}$ with a bandwidth of about 0.5 Hz, corresponding to a sensitivity to short GW bursts of \\textit{h} = 6 10$^{-19}$.\\\\ \\\\This sensitivity should allow the detection of the burst sources in our Galaxy and in the Local Group. No evidence of GW signals has been reported up to now.\\\\ \\\\The principle of operation is based on the assumption that any vibrational mode of a resonant bo...
Stochastic background of gravitational waves
D'Araújo, J C N; Aguiar, O D
2000-01-01
A continuous stochastic background of gravitational waves (GWs) for burst sources is produced if the mean time interval between the occurrence of bursts is smaller than the average time duration of a single burst at the emission, i.e., the so called duty cycle must be greater than one. To evaluate the background of GWs produced by an ensemble of sources, during their formation, for example, one needs to know the average energy flux emitted during the formation of a single object and the formation rate of such objects as well. In many cases the energy flux emitted during an event of production of GWs is not known in detail, only characteristic values for the dimensionless amplitude and frequencies are known. Here we present a shortcut to calculate stochastic backgrounds of GWs produced from cosmological sources. For this approach it is not necessary to know in detail the energy flux emitted at each frequency. Knowing the characteristic values for the ``lumped'' dimensionless amplitude and frequency we show tha...
Gravitational wave detection in space
Ni, Wei-Tou
2016-01-01
Gravitational wave (GW) detection in space is aimed at low frequency band (100 nHz - 100 mHz) and middle frequency band (100 mHz - 10 Hz). The science goals are the detection of GWs from (i) Supermassive Black Holes; (ii) Extreme-Mass-Ratio Black Hole Inspirals; (iii) Intermediate-Mass Black Holes; (iv) Galactic Compact Binaries and (v) Relic GW Background. In this paper, we present an overview on the sensitivity, orbit design, basic orbit configuration, angular resolution, orbit optimization, deployment, time-delay interferometry and payload concept of the current proposed GW detectors in space under study. The detector proposals under study have arm length ranging from 1000 km to 1.3 x 109 km (8.6 AU) including (a) Solar orbiting detectors -- ASTROD-GW (ASTROD [Astrodynamical Space Test of Relativity using Optical Devices] optimized for GW detection), BBO (Big Bang Observer), DECIGO (DECi-hertz Interferometer GW Observatory), e-LISA (evolved LISA [Laser Interferometer Space Antenna]), LISA, other LISA-type ...
Gravitational Waves from Axion Monodromy
Hebecker, Arthur; Rompineve, Fabrizio; Witkowski, Lukas T
2016-01-01
Large field inflation is arguably the simplest and most natural variant of slow-roll inflation. Axion monodromy may be the most promising framework for realising this scenario. As one of its defining features, the long-range polynomial potential possesses short-range, instantonic modulations. These can give rise to a series of local minima in the post-inflationary region of the potential. We show that for certain parameter choices the inflaton populates more than one of these vacua inside a single Hubble patch. This corresponds to a dynamical phase decomposition, analogously to what happens in the course of thermal first-order phase transitions. In the subsequent process of bubble wall collisions, the lowest-lying axionic minimum eventually takes over all space. Our main result is that this violent process sources gravitational waves, very much like in the case of a first-order phase transition. We compute the energy density and peak frequency of the signal, which can lie anywhere in the mHz-GHz range, possib...
Gravitational Lensing by Burkert Halos
Park, Y; Park, Yousin; Ferguson, Henry C.
2003-01-01
We investigate the gravitational lensing properties of dark matter halos with Burkert profiles. We derive an analytic expression for the lens equation and use it to compute the magnification, impact parameter and image separations for strong lensing. For the scaling relation that provides the best fits to spiral-galaxy rotation curve data, Burkert halos will not produce strong lensing, even if this scaling relation extends up to masses of galaxy clusters. Tests of a simple model of an exponential stellar disk superimposed on a Burkert-profile halo demonstrate that strong lensing is unlikely without an additional concentration of mass in the galaxy center (e.g. a bulge). The fact that most strong lenses on galactic scales are elliptical galaxies suggests that a strong central concentration of baryons is required to produce image splitting. This solution is less attractive for clusters of galaxies, which are generally considered to be dark-matter dominated even at small radii. There are three possible implicati...
CHAOTIC ZONES AROUND GRAVITATING BINARIES
Energy Technology Data Exchange (ETDEWEB)
Shevchenko, Ivan I., E-mail: iis@gao.spb.ru [Pulkovo Observatory of the Russian Academy of Sciences, Pulkovskoje ave. 65, St. Petersburg 196140 (Russian Federation)
2015-01-20
The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.
Gravitational Effects upon Locomotion Posture
DeWitt, John K.; Bentley, Jason R.; Edwards, W. Brent; Perusek, Gail P.; Samorezov, Sergey
2008-01-01
Researchers use actual microgravity (AM) during parabolic flight and simulated microgravity (SM) obtained with horizontal suspension analogs to better understand the effect of gravity upon gait. In both environments, the gravitational force is replaced by an external load (EL) that returns the subject to the treadmill. However, when compared to normal gravity (N), researchers consistently find reduced ground reaction forces (GRF) and subtle kinematic differences (Schaffner et al., 2005). On the International Space Station, the EL is applied by elastic bungees attached to a waist and shoulder harness. While bungees can provide EL approaching body weight (BW), their force-length characteristics coupled with vertical oscillations of the body during gait result in a variable load. However, during locomotion in N, the EL is consistently equal to 100% body weight. Comparisons between AM and N have shown that during running, GRF are decreased in AM (Schaffner et al, 2005). Kinematic evaluations in the past have focussed on joint range of motion rather than joint posture at specific instances of the gait cycle. The reduced GRF in microgravity may be a result of differing hip, knee, and ankle positions during contact. The purpose of this investigation was to compare joint angles of the lower extremities during walking and running in AM, SM, and N. We hypothesized that in AM and SM, joints would be more flexed at heel strike (HS), mid-stance (MS) and toe-off (TO) than in N.
Anomalous magnetic properties of VOx multiwall nanotubes
Demishev, S. V.; Chernobrovkin, A. L.; Glushkov, V. V.; Goodilin, E. A.; Grigorieva, A. V.; Ishchenko, T. V.; Kuznetsov, A. V.; Sluchanko, N. E.; Tretyakov, Yu D.; Semeno, A. V.
2010-01-01
Basing on the high frequency (60 GHz) electron spin resonance (ESR) and magnetic susceptibility study of the VOx multiwall nanotubes (VOx-NTs) in the range 4.2-300 K we report the ESR evidence of the presence of the antiferromagnetic V4+ dimers in VOx-NTs and the observation of an anomalous low temperature (T<50 K) growth of the magnetic susceptibility for V4+ quasi-free spins, which obey power law χ(T)~1/Tα with the exponent αapprox0.6. The estimates of the concentrations for various spin species (clusters) indicate that the non-interacting dimers should be an essential element in the VOx-NTs structure. The possibility of the disorder driven quantum critical regime in VOx-NTs is discussed.
Anomalous velocity distributions in active Brownian suspensions.
Fiege, Andrea; Vollmayr-Lee, Benjamin; Zippelius, Annette
2013-08-01
Large-scale simulations and analytical theory have been combined to obtain the nonequilibrium velocity distribution, f(v), of randomly accelerated particles in suspension. The simulations are based on an event-driven algorithm, generalized 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 this one-particle model and solved it analytically in the limit of strong damping, where we find that f(v) decays as 1/v for multiple decades, eventually crossing over to a Gaussian decay for the largest velocities. Many particle simulations and numerical solution of the one-particle model agree for all values of the damping. PMID:24032806
The anomalous quadrupole collectivity in Te isotopes
Qi, Chong
2016-01-01
We present systematic calculations on the spectroscopy and transition properties of even-even Te isotopes by using the large-scale configuration interaction shell model approach with a realistic interaction. These nuclei are of particular interest since their yrast spectra show a vibrational-like equally-spaced pattern but the few known E2 transitions show anomalous rotational-like behavior, which cannot be reproduced by collective models. Our calculations reproduce well the equally-spaced spectra of those isotopes as well as the constant behavior of the $B(E2)$ values in $^{114}$Te. The calculated $B(E2)$ values for neutron-deficient and heavier Te isotopes show contrasting different behaviors along the yrast line. The $B(E2)$ of light isotopes can exhibit a nearly constant bevavior upto high spins. We show that this is related to the enhanced neutron-proton correlation when approaching $N=50$.
Anomalous rectification in a purely electronic memristor
Wang, Jingrui; Pan, Ruobing; Cao, Hongtao; Wang, Yang; Liang, Lingyan; Zhang, Hongliang; Gao, Junhua; Zhuge, Fei
2016-10-01
An anomalous rectification was observed in a purely electronic memristive device Ti/ZnO/Pt. It could be due to (1) an Ohmic or quasi-Ohmic contact at the ZnO/Pt interface and (2) a Schottky contact at the Ti/ZnO interface. The Ohmic contact originates from the reduction of ZnO occurring in the whole film instead of only at the Ti/ZnO interface. The Schottky contact may come from moisture adsorbed in the nanoporous ZnO. The conduction in the electroformed device is controlled by the carrier trapping/detrapping of the trap sites, inducing a poor rectification and high nonlinearity. Furthermore, a complementary resistive switching was achieved.
44th Annual Anomalous Absorption Conference
Energy Technology Data Exchange (ETDEWEB)
Beg, Farhat
2014-03-03
Conference Grant Report July 14, 2015 Submitted to the U. S. Department of Energy Attn: Dr. Sean Finnegan By the University of California, San Diego 9500 Gilman Drive La Jolla, California 92093 On behalf of the 44th Annual Anomalous Absorption Conference 8-13 June 2014, in Estes Park, Colorado Support Requested: $10,100 Amount expended: $3,216.14 Performance Period: 1 March 20 14 to 28 February 20 15 Principal Investigator Dr. Farhat Beg Center for Energy Research University of California, San Diego 9500 Gilman Drive La Jolla, California 92093-0417 858-822-1266 (telephone) 858-534-4543 (fax) fbeg@ucsd.edu Administrative Point of Contact: Brandi Pate, 858-534-0851, blpate®ucsd.edu I. Background The forty-fourth Anomalous Absorption Conference was held in Estes Park, Colorado from June 5-8, 2014 (aac2014.ucsd.edu). The first Anomalous Absorption Conference was held in 1971 to assemble experts in the poorly understood area of laser-plasma absorption. The goal of that conference was to address the anomalously large laser absorption seen in plasma experiments with respect to the laser absorption predicted by linear plasma theory. Great progress in this research area has been made in the decades since that first meeting, due in part to the scientific interactions that have occurred annually at this conference. Specifically, this includes the development of nonlinear laser-plasma theory and the simulation of laser interactions with plasmas. Each summer since that first meeting, this week-long conference has been held at unique locations in North America as a scientific forum for intense scientific exchanges relevant to the interaction of laser radiation with plasmas. Responsibility for organizing the conference has traditional rotated each year between the major Inertial Confinement Fusion (ICF) laboratories and universities including LANL, LLNL, LLE, UCLA UC Davis and NRL. As the conference has matured over the past four decades, its technical footprint has expanded
Anomalous magnetoresistance in magnetized topological insulator cylinders
Energy Technology Data Exchange (ETDEWEB)
Siu, Zhuo Bin, E-mail: a0018876@nus.edu.sg [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore); Data Storage Institute, Agency for Science, Technology and Research, Singapore 117608 (Singapore); Jalil, Mansoor B. A. [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore)
2015-05-07
The close coupling between the spin and momentum degrees of freedom in topological insulators (TIs) presents the opportunity for the control of one to manipulate the other. The momentum can, for example, be confined on a curved surface and the spin influenced by applying a magnetic field. In this work, we study the surface states of a cylindrical TI magnetized in the x direction perpendicular to the cylindrical axis lying along the z direction. We show that a large magnetization leads to an upwards bending of the energy bands at small |k{sub z}|. The bending leads to an anomalous magnetoresistance where the transmission between two cylinders magnetized in opposite directions is higher than when the cylinders are magnetized at intermediate angles with respect to each other.
The Anomalous Acceleration of the Pioneer Spacecrafts
de Diego, Jose A
2008-01-01
Radiometric data from the Pioneer 10 and 11 spacecrafts have revealed an unexplained constant acceleration of a_A = (8.74 +/- 1.33) x 10^(-10) m s^(-2) towards the Sun, also known as the Pioneer anomaly. Different groups have analyzed the Pioneer data and have got the same results, which rules out computer programming and handling errors. Attempts to explain this phenomenon arguing intrinsic causes on-board the spacecrafts failed or have lead to inconclusive results. Therefore, the Pioneer anomalous acceleration has motivated the interest of researchers to find out explanations that could bring insight upon the forces acting in the outer Solar Systems or a hint to discover new natural laws.
Anomalous conductances in an ultracold quantum wire
Kanász-Nagy, Márton; Esslinger, Tilman; Demler, Eugene A
2016-01-01
We analyze the recently measured anomalous transport properties of an ultracold gas through a ballistic constriction [S. Krinner et al., PNAS 201601812 (2016)]. The quantized conductance observed at weak interactions increases several-fold as the gas is made strongly interacting, which cannot be explained by the Landauer theory of single-channel transport. We show that this phenomenon is due to the multichannel Andreev reflections at the edges of the constriction, where the interaction and confinement result in a superconducting state. Andreev processes convert atoms of otherwise reflecting channels into the condensate propagating through the constriction, leading to a significant excess conductance. Furthermore, we find the spin conductance being suppressed by superconductivity; the agreement with experiment provides an additional support for our model.
Anomalous transport from holography: Part I
Bu, Yanyan; Sharon, Amir
2016-01-01
We revisit the transport properties induced by the chiral anomaly in a charged plasma holographically dual to anomalous $U(1)_V\\times U(1)_A$ Maxwell theory in Schwarzschild-$AdS_5$. Off-shell constitutive relations for vector and axial currents are derived using various approximations generalising most of known in the literature anomaly-induced phenomena and revealing some new ones. In a weak external field approximation, the constitutive relations have all-order derivatives resummed into six momenta-dependent transport coefficient functions: the diffusion, the electric/magnetic conductivity, and three anomaly induced functions. The latter generalise the chiral magnetic and chiral separation effects. Nonlinear transport is studied assuming presence of constant background external fields. The chiral magnetic effect, including all order nonlinearity in magnetic field, is proven to be exact when the magnetic field is the only external field that is turned on. Non-linear corrections to the constitutive relations...
Communication: Probing anomalous diffusion in frequency space
International Nuclear Information System (INIS)
Anomalous diffusion processes are usually detected by analyzing the time-dependent mean square displacement of the diffusing particles. The latter evolves asymptotically as W(t) ∼ 2Dαtα, where Dα is the fractional diffusion constant and 0 < α < 2. In this article we show that both Dα and α can also be extracted from the low-frequency Fourier spectrum of the corresponding velocity autocorrelation function. This offers a simple method for the interpretation of quasielastic neutron scattering spectra from complex (bio)molecular systems, in which subdiffusive transport is frequently encountered. The approach is illustrated and validated by analyzing molecular dynamics simulations of molecular diffusion in a lipid POPC bilayer
Anomalous Wtb coupling at the LHC
Kolodziej, K
2013-01-01
Some normalized distributions of the secondary mu- in the top quark pair production at the LHC through one of the dominant hard scattering reactions gg -> b u anti-d anti-b mu- anti-nu_mu are calculated to leading order in the presence of the most general anomalous Wtb coupling with operators up to dimension five. In spite of the fact that non zero tensor form factors of the coupling modify substantially the top quark pair production rate, they hardly affect the distributions in the transverse momentum, rapidity and cosine of the angle between the momenta of mu- and recoiling top quark in the pp centre of mass frame. The effects of the tensor form factors become visible in distributions in cosine of the angle between the momentum of mu- and the reversed momentum of the b-quark, both boosted first to the rest frame of top quark and then to the rest frame of W-boson.
Can Anomalous Amplification be Attained without Postselection?
Martínez-Rincón, Julián; Liu, Wei-Tao; Viza, Gerardo I.; Howell, John C.
2016-03-01
We present a parameter estimation technique based on performing joint measurements of a weak interaction away from the weak-value-amplification approximation. Two detectors are used to collect full statistics of the correlations between two weakly entangled degrees of freedom. Without discarding of data, the protocol resembles the anomalous amplification of an imaginary-weak-value-like response. The amplification is induced in the difference signal of both detectors allowing robustness to different sources of technical noise, and offering in addition the advantages of balanced signals for precision metrology. All of the Fisher information about the parameter of interest is collected. A tunable phase controls the strength of the amplification response. We experimentally demonstrate the proposed technique by measuring polarization rotations in a linearly polarized laser pulse. We show that in the presence of technical noise the effective sensitivity and precision of a split detector is increased when compared to a conventional continuous-wave balanced detection technique.
Anomalously Weak Dynamical Friction in Halos
Sellwood, J A
2005-01-01
A bar rotating in a pressure-supported halo generally loses angular momentum and slows down due to dynamical friction. Valenzuela & Klypin report a counter-example of a bar that rotates in a dense halo with little friction for several Gyr, and argue that their result invalidates the claim by Debattista & Sellwood that fast bars in real galaxies require a low halo density. We show that it is possible for friction to cease for a while should the pattern speed of the bar fluctuate upward. The reduced friction is due to an anomalous gradient in the phase-space density of particles at the principal resonance created by the earlier evolution. The result obtained by Valenzuela & Klypin is probably an artifact of their adaptive mesh refinement method, but anyway could not persist in a real galaxy. The conclusion by Debattista & Sellwood still stands.
Anomalous Dynamical Responses in a Driven System
Dutta, Suman
2016-01-01
The interplay between structure and dynamics in non-equilibrium steady-state is far from understood. We address this interplay by tracking Brownian Dynamics trajectories of particles in a binary colloid of opposite charges in an external electric field, undergoing cross-over from homogeneous to lane state, a prototype of heterogeneous structure formation in non-equilibrium systems. We show that the length scale of structural correlations controls heterogeneity in diffusion and consequent anomalous dynamic responses, like the exponential tail in probability distributions of particle displacements and stretched exponential structural relaxation. We generalise our observations using equations for steady state density which may aid to understand microscopic basis of heterogeneous diffusion in condensed matter systems.
Latest results on $J/$ anomalous suppression
Indian Academy of Sciences (India)
Sérgio Ramos; NA50 Collaboration; B Allessandro; C Alexa; R Arnaldi; M Atayan; C Baglin; A Baldit; M Bedjidian; S Beolè; V Boldea; P Bordalo; S R Borenstein; G Borges; A Bussière; L Capelli; C Castanier; J Castor; B Chaurand; B Cheynis; E Chiavassa; C Cicalo; T Claudino; M P Comets; S Constantinescu; P Cortese; J Cruz; A DeFalco; N DeMarco; G Dellacasa; A Devaux; S Dita; O Drapier; B Espagnon; J Fargeix; P Force; M Gallio; Y K Gavrilov; C Gerschel; P Giubellino; M B Golubeva; M Gonin; A A Grigorian; S Grigorian; J Y Grossiord; F F Guber; A Guichard; H Gulkanyan; R Hakobyan; R Haroutunian; M Idzik; D Jouan; T L Karavitcheva; L Kluberg; A B Kurepin; Y Le Bornée; C Lourenço; P Macciotta; M Mac Cormick; A Marzari-Chiesa; M Masera; A Masoni; M Monteno; A Musso; P Petiau; A Piccotti; J R Pizzi; W L Prado da Silva; F Prino; G Puddu; C Quintans; L Ramello; S Ramos; P Rato Mendes; L Riccati; A Romana; H Santos; P Saturnini; E Scalas; E Scomparin; S Serci; R Shahoyan; F Sigaudo; M Sitta; P Sonderegger; X Tarrago; N S Topilskaya; G L Usai; E Vercellin; L Villatte; N Willis; T Wu
2004-03-01
The NA50 experiment deals with Pb–Pb collisions at 158 GeV/nucleon at the CERN SPS accelerator. The $J/$ production is studied through the muon decay channel, using the Drell–Yan dimuons as a reference. New results based on recent analyses, from data taken with improved experimental conditions and using different centrality estimators, are presented and compared to an update of those already obtained from previous data samples. The stepwise pattern of the anomalous $J/$ suppression as a function of centrality, already present in these previous results, is confirmed. This observation could be a fingerprint of the theoretically predicted melting of charmonia resonances in a deconfined quark–gluon plasma.
Communication: Probing anomalous diffusion in frequency space
Energy Technology Data Exchange (ETDEWEB)
Stachura, Sławomir [Centre de Biophys. Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans (France); Synchrotron Soleil, L’Orme de Merisiers, 91192 Gif-sur-Yvette (France); Kneller, Gerald R., E-mail: gerald.kneller@cnrs-orleans.fr [Centre de Biophys. Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans (France); Synchrotron Soleil, L’Orme de Merisiers, 91192 Gif-sur-Yvette (France); Université d’Orléans, Chateau de la Source-Av. du Parc Floral, 45067 Orléans (France)
2015-11-21
Anomalous diffusion processes are usually detected by analyzing the time-dependent mean square displacement of the diffusing particles. The latter evolves asymptotically as W(t) ∼ 2D{sub α}t{sup α}, where D{sub α} is the fractional diffusion constant and 0 < α < 2. In this article we show that both D{sub α} and α can also be extracted from the low-frequency Fourier spectrum of the corresponding velocity autocorrelation function. This offers a simple method for the interpretation of quasielastic neutron scattering spectra from complex (bio)molecular systems, in which subdiffusive transport is frequently encountered. The approach is illustrated and validated by analyzing molecular dynamics simulations of molecular diffusion in a lipid POPC bilayer.
Anomalous water absorption in porous materials
Lockington, D A
2003-01-01
The absorption of fluid by unsaturated, rigid porous materials may be characterized by the sorptivity. This is a simple parameter to determine and is increasingly being used as a measure of a material's resistance to exposure to fluids (especially moisture and reactive solutes) in aggressive environments. The complete isothermal absorption process is described by a nonlinear diffusion equation, with the hydraulic diffusivity being a strongly nonlinear function of the degree of saturation of the material. This diffusivity can be estimated from the sorptivity test. In a typical test the cumulative absorption is proportional to the square root of time. However, a number of researchers have observed deviation from this behaviour when the infiltrating fluid is water and there is some potential for chemo-mechanical interaction with the material. In that case the current interpretation of the test and estimation of the hydraulic diffusivity is no longer appropriate. Kuentz and Lavallee (2001) discuss the anomalous b...
Can Anomalous Amplification be Attained Without Postselection?
Martínez-Rincón, Julián; Viza, Gerardo I; Howell, John C
2015-01-01
We present a parameter estimation technique based on performing joint measurements of a weak interaction away from the weak-value-amplification approximation. Two detectors are used to collect full statistics of the correlations between two weakly entangled degrees of freedom. Without the need of postselection, the protocol resembles the anomalous amplification of an imaginary-weak-value-like response. The amplification is induced in the difference signal of both detectors allowing robustness to different sources of technical noise, and offering in addition the advantages of balanced signals for precision metrology. All of the Fisher information about the parameter of interest is collected, and a phase controls the amplification response. We experimentally demonstrate the proposed technique by measuring polarization rotations in a linearly polarized laser pulse. The effective sensitivity and precision of a split detector is increased when compared to a conventional continuous-wave balanced detection technique...
Anomalous anisotropic magnetoresistance effects in graphene
Directory of Open Access Journals (Sweden)
Yiwei Liu
2014-09-01
Full Text Available We investigate the effect of external stimulus (temperature, magnetic field, and gases adsorptions on anisotropic magnetoresistance (AMR in multilayer graphene. The graphene sample shows superlinear magnetoresistance when magnetic field is perpendicular to the plane of graphene. A non-saturated AMR with a value of −33% is found at 10 K under a magnetic field of 7 T. It is surprisingly to observe that a two-fold symmetric AMR at high temperature is changed into a one-fold one at low temperature for a sample with an irregular shape. The anomalous AMR behaviors may be understood by considering the anisotropic scattering of carriers from two asymmetric edges and the boundaries of V+(V- electrodes which serve as active adsorption sites for gas molecules at low temperature. Our results indicate that AMR in graphene can be optimized by tuning the adsorptions, sample shape and electrode distribution in the future application.
Quantum anomalous Hall effect with higher plateaus.
Wang, Jing; Lian, Biao; Zhang, Haijun; Xu, Yong; Zhang, Shou-Cheng
2013-09-27
The quantum anomalous Hall (QAH) effect in magnetic topological insulators is driven by the combination of spontaneous magnetic moments and spin-orbit coupling. Its recent experimental discovery raises the question if higher plateaus can also be realized. Here, we present a general theory for a QAH effect with higher Chern numbers and show by first-principles calculations that a thin film magnetic topological insulator of Cr-doped Bi2(Se,Te)3 is a candidate for the C=2 QAH insulator. Remarkably, whereas a higher magnetic field leads to lower Hall conductance plateaus in the integer quantum Hall effect, a higher magnetic moment leads to higher Hall conductance plateaus in the QAH effect.
Dynamical Space-Time and Gravitational Waves
van Holten, J W
2016-01-01
According to General Relativity gravity is the result of the interaction between matter and space-time geometry. In this interaction space-time geometry itself is dynamical: it can store and transport energy and momentum in the form of gravitational waves. We give an introductory account of this phenomenon and discuss how the observation of gravitational waves may open up a fundamentally new window on the universe.
On the Possibility to Construct Gravitational Eye
Institute of Scientific and Technical Information of China (English)
CHEN Ying-Tian
2007-01-01
The possibility of modifying a conventional Cavendish torsion pendulum into a half-armed pendulum oscillator to measure the horizontal gravitational acceleration is discussed. A new kind of gravitational detector, gravieye,as we named, can be made by a proper combination of such oscillators to "see" remote objects and to be used, e.g. to detect the movement of huge mass at a long distance.