Variation of Fundamental Constants
Flambaum, V. V.
2006-11-01
Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. The spatial variation can explain a fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. We present a review of recent works devoted to the variation of the fine structure constant α, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra. Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feshbach resonance.
Variation of fundamental constants
Flambaum, V V
2006-01-01
We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.
Variation of fundamental constants: theory
Flambaum, Victor
2008-05-01
Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. There are some hints for the variation of different fundamental constants in quasar absorption spectra and Big Bang nucleosynthesis data. A large number of publications (including atomic clocks) report limits on the variations. We want to study the variation of the main dimensionless parameters of the Standard Model: 1. Fine structure constant alpha (combination of speed of light, electron charge and Plank constant). 2. Ratio of the strong interaction scale (LambdaQCD) to a fundamental mass like electron mass or quark mass which are proportional to Higgs vacuum expectation value. The proton mass is propotional to LambdaQCD, therefore, the proton-to-electron mass ratio comes into this second category. We performed necessary atomic, nuclear and QCD calculations needed to study variation of the fundamental constants using the Big Bang Nucleosynthsis, quasar spectra, Oklo natural nuclear reactor and atomic clock data. The relative effects of the variation may be enhanced in transitions between narrow close levels in atoms, molecules and nuclei. If one will study an enhanced effect, the relative value of systematic effects (which are not enhanced) may be much smaller. Note also that the absolute magnitude of the variation effects in nuclei (e.g. in very narrow 7 eV transition in 229Th) may be 5 orders of magnitude larger than in atoms. A different possibility of enhancement comes from the inversion transitions in molecules where splitting between the levels is due to the quantum tunneling amplitude which has strong, exponential dependence on the electron to proton mass ratio. Our study of NH3 quasar spectra has already given the best limit on the variation of electron to proton mass ratio.
Spatial Variations of Fundamental Constants
Barrow, John D; Barrow, John D.; Toole, Chris O'
1999-01-01
We show that observational limits on the possible time variation of constants of Nature are significantly affected by allowing for both space and time variation. Bekenstein's generalisation of Maxwell's equations to allow for cosmological variation of $alpha$ is investigated in a universe containing spherically symmetric inhomogeneities. The time variation of $alpha$ is determined by the local matter density and hence limits obtained in high-density geophysical enviroments are far more constraining than those obtained at high redshift. This new feature is expected to be a property of a wide class of theories for the variation of constants.
Variation of fundamental constants: theory and observations
Flambaum, V V
2007-01-01
Review of recent works devoted to the variation of the fundamental constants is presented including atomic clocks, quasar absorption spectra, and Oklo natural nuclear reactor data. Assuming linear variation with time we can compare different results. From the quasar absorption spectra: $\\dot{\\mu}/\\mu=(1 \\pm 3) \\times 10^{-16}$ yr$^{-1}$. A combination of this result and the atomic clock results gives the best limt on variation of $\\alpha$: $\\dot{\\alpha}/\\alpha=(-0.8 \\pm 0.8) \\times 10^{-16}$ yr$^{-1}$. The Oklo natural reactor gives the best limit on the variation of $m_s/\\Lambda_{QCD}$ where $m_s$ is the strange quark mass. Huge enhancement of the relative variation effects happens in transitions between close atomic, molecular and nuclear energy levels. We suggest several new cases where the levels are very narrow. Large enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feshbach resonance. Massive bodies (stars or galaxies) can also affect physical constants....
Variations of fundamental constants and multidimensional gravity
Bronnikova, K. A.; Skvortsova, M. V.
We try to explain the recently reported large-scale spatial variations of the fine structure constant α, in agreement with other cosmological observations, in the framework of curvature-nonlinear multidimensional gravity. The original theory is reduced to a scalar-tensor theory in four dimensions, and the corresponding isotropic cosmologies are considered in both Einstein and Jordan conformal frames. In the Jordan frame one obtains simultaneous variations of α and the gravitational constant G, equal in magnitude. Long-wave small inhomogeneous perturbations of isotropic models allow for explaining spatial variations of α.
Search for a Variation of Fundamental Constants
Ubachs, W.
2013-06-01
Since the days of Dirac scientists have speculated about the possibility that the laws of nature, and the fundamental constants appearing in those laws, are not rock-solid and eternal but may be subject to change in time or space. Such a scenario of evolving constants might provide an answer to the deepest puzzle of contemporary science, namely why the conditions in our local Universe allow for extreme complexity: the fine-tuning problem. In the past decade it has been established that spectral lines of atoms and molecules, which can currently be measured at ever-higher accuracies, form an ideal test ground for probing drifting constants. This has brought this subject from the realm of metaphysics to that of experimental science. In particular the spectra of molecules are sensitive for probing a variation of the proton-electron mass ratio μ, either on a cosmological time scale, or on a laboratory time scale. A comparison can be made between spectra of molecular hydrogen observed in the laboratory and at a high redshift (z=2-3), using the Very Large Telescope (Paranal, Chile) and the Keck telescope (Hawaii). This puts a constraint on a varying mass ratio Δμ/μ at the 10^{-5} level. The optical work can also be extended to include CO molecules. Further a novel direction will be discussed: it was discovered that molecules exhibiting hindered internal rotation have spectral lines in the radio-spectrum that are extremely sensitive to a varying proton-electron mass ratio. Such lines in the spectrum of methanol were recently observed with the radio-telescope in Effelsberg (Germany). F. van Weerdenburg, M.T. Murphy, A.L. Malec, L. Kaper, W. Ubachs, Phys. Rev. Lett. 106, 180802 (2011). A. Malec, R. Buning, M.T. Murphy, N. Milutinovic, S.L. Ellison, J.X. Prochaska, L. Kaper, J. Tumlinson, R.F. Carswell, W. Ubachs, Mon. Not. Roy. Astron. Soc. 403, 1541 (2010). E.J. Salumbides, M.L. Niu, J. Bagdonaite, N. de Oliveira, D. Joyeux, L. Nahon, W. Ubachs, Phys. Rev. A 86, 022510
Planck intermediate results XXIV. Constraints on variations in fundamental constants
DEFF Research Database (Denmark)
Ade, P. A. R.; Aghanim, N.; Arnaud, M.;
2015-01-01
Any variation in the fundamental physical constants, more particularly in the fine structure constant, a, or in the mass of the electron, me, affects the recombination history of the Universe and cause an imprint on the cosmic microwave background angular power spectra. We show that the Planck data...... of the electron, me, and in the simultaneous variation of the two constants. We examine in detail the degeneracies between fundamental constants and the cosmological parameters, in order to compare the limits obtained from Planck and WMAP and to determine the constraining power gained by including other...
Early Universe Constraints on Time Variation of Fundamental Constants
Landau, Susana J; Scoccola, Claudia G; Vucetich, Hector
2008-01-01
We study the time variation of fundamental constants in the early Universe. Using data from primordial light nuclei abundances, CMB and the 2dFGRS power spectrum, we put constraints on the time variation of the fine structure constant $\\alpha$, and the Higgs vacuum expectation value $$ without assuming any theoretical framework. A variation in $$ leads to a variation in the electron mass, among other effects. Along the same line, we study the variation of $\\alpha$ and the electron mass $m_e$. In a purely phenomenological fashion, we derive a relationship between both variations.
Planck intermediate results. XXIV. Constraints on variation of fundamental constants
Ade, P A R; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Battaner, E.; Benabed, K.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Burigana, C.; Butler, R.C.; Calabrese, E.; Chamballu, A.; Chiang, H.C.; Christensen, P.R.; Clements, D.L.; Colombo, L.P.L.; Couchot, F.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Diego, J.M.; Dole, H.; Dore, O.; Dupac, X.; Ensslin, T.A.; Eriksen, H.K.; Fabre, O.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gregorio, A.; Gruppuso, A.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, A.H.; Jones, W.C.; Keihanen, E.; Keskitalo, R.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lamarre, J.M.; Lasenby, A.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Mandolesi, N.; Maris, M.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Menegoni, E.; Mennella, A.; Migliaccio, M.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Moss, A.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G.W.; Prunet, S.; Rachen, J.P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Ristorcelli, I.; Rocha, G.; Roudier, G.; Rusholme, B.; Sandri, M.; Savini, G.; Scott, D.; Spencer, L.D.; Stolyarov, V.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Uzan, J.P.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L.A.; Yvon, D.; Zacchei, A.; Zonca, A.
2015-01-01
Any variation of the fundamental physical constants, and more particularly of the fine structure constant, $\\alpha$, or of the mass of the electron, $m_e$, would affect the recombination history of the Universe and cause an imprint on the cosmic microwave background angular power spectra. We show that the Planck data allow one to improve the constraint on the time variation of the fine structure constant at redshift $z\\sim 10^3$ by about a factor of 5 compared to WMAP data, as well as to break the degeneracy with the Hubble constant, $H_0$. In addition to $\\alpha$, we can set a constraint on the variation of the mass of the electron, $m_{\\rm e}$, and on the simultaneous variation of the two constants. We examine in detail the degeneracies between fundamental constants and the cosmological parameters, in order to compare the limits obtained from Planck and WMAP and to determine the constraining power gained by including other cosmological probes. We conclude that independent time variations of the fine structu...
Variation of the Fundamental Constants:. Theory and Observations
Flambaum, V. V.
2007-10-01
Review of recent works devoted to the variation of the fine structure constant α, strong interaction and fundamental masses (Higgs vacuum) is presented. The results from Big Bang nucleosynthesis, quasar absorption spectra, and Oklo natural nuclear reactor data give us the space-time variation on the Universe lifetime scale. Comparison of different atomic clocks gives us the present time variation. Assuming linear variation with time we can compare different results. The best limit on the variation of the electron-to-proton mass ratio μ = me/Mp and Xe = me/ΛQCD follows from the quasar absorption spectra:1 ˙ {μ }/μ = ˙ {X}e/X_e = (1 ± 3) × 10-16 yr-1. A combination of this result and the atomic clock results2,3 gives the best limt on variation of α : ˙ {α }/α = (-0.8 ± 0.8) × 10-16 yr-1. The Oklo natural reactor gives the best limit on the variation of Xs = ms/ΛQCD where ms is the strange quark mass:4,5 ∣ ˙ {X}s/X_s∣ < 10-18 yr-1. Note that the Oklo data can not give us any limit on the variation of a since the effect of α there is much smaller than the effect of Xs and should be neglected. Huge enhancement of the relative variation effects happens in transitions between close atomic, molecular and nuclear energy levels. We suggest several new cases where the levels are very narrow. Large enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feshbach resonance. How changing physical constants and violation of local position invariance may occur? Light scalar fields very naturally appear in modern cosmological models, affecting parameters of the Standard Model (e.g. α). Cosmological variations of these scalar fields should occur because of drastic changes of matter composition in Universe: the latest such event is rather recent (about 5 billion years ago), from matter to dark energy domination. Massive bodies (stars or galaxies) can also affect physical constants. They have large scalar charge S
Orbital effects of spatial variations of fundamental coupling constants
Iorio, Lorenzo
2011-01-01
We deal with the effects induced on the orbit of a test particle revolving around a central body by putative spatial variations of fundamental coupling constants $\\zeta$. In particular, we assume a dipole gradient for $\\zeta(\\bds r)/\\bar{\\zeta}$ along a generic direction $\\bds{\\hat{k}}$ in space. We analytically work out the long-term variations of all the six standard Keplerian orbital elements parameterizing the orbit of a test particle in a gravitationally bound two-body system. It turns out that, apart from the semi-major axis $a$, the eccentricity $e$, the inclination $I$, the longitude of the ascending node $\\Omega$, the longitude of pericenter $\\pi$ and the mean anomaly $\\mathcal{M}$ undergo non-zero long-term changes. By using the usual decomposition along the radial ($R$), transverse ($T$) and normal ($N$) directions, we also analytically work out the long-term changes $\\Delta R,\\Delta T,\\Delta N$ and $\\Delta v_R,\\Delta v_T,\\Delta v_N$ experienced by the position and the velocity vectors $\\bds r$ and...
Violation of fundamental symmetries and variation of fundamental constants in atomic phenomena
Flambaum, V. V.
2007-06-01
We present a review of recent works on variation of fundamental constants and violation of parity in atoms and nuclei. Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. The spatial variation can explain fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. We describe recent works devoted to the variation of the fine structure constant α, strong interaction and fundamental masses (Higgs vacuum). There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transitions between very close atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on UV transition in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Measurements of violation of fundamental symmetries, parity (P) and time reversal (T), in atoms allows one to test unification theories in atomic experiments. We have developed an accurate method of many-body calculations - all-orders summation of dominating diagrams in residual e-e interaction. To calculate QED radiative corrections to energy levels and electromagnetic amplitudes in many-electron atoms and molecules we derived the ``radiative potential'' and the low-energy theorem. This method is simple and can be easily incorporated into any many-body theory approach. Using the radiative correction and many-body calculations we obtained the PNC amplitude EPNC = -0.898(1 +/- 0.5%) × 10-11ieaB(-QW/N). From the measurements of the PNC amplitude we extracted the Cs weak charge QW = -72.66(29)exp(36)theor. The
Planck intermediate results XXIV. Constraints on variations in fundamental constants
DEFF Research Database (Denmark)
Ade, P. A. R.; Aghanim, N.; Arnaud, M.
2015-01-01
cosmological probes. We conclude that independent time variations of the fine structure constant and of the mass of the electron are constrained by Planck to Δ Α/Α = (3.6±3.7) x 10-3 and Δ me/me = (4 ±11) x 10-3 at the 68% confidence level. We also investigate the possibility of a spatial variation of the fine...
Limits on the space-time variations of fundamental constants
Levshakov, S A; Reimers, D; Molaro, P
2013-01-01
We report on new tests that improve our previous (2009-2010) estimates of the electron-to-proton mass ratio variation, mu = m_e/m_p. Subsequent observations (2011-2013) at the Effelsberg 100-m telescope of a sample of eight molecular cores from the Milky Way disk reveal systematic errors in the measured sky frequencies varying with an amplitude +/-0.01 km/s during the exposure time. The averaged offset between the radial velocities of the NH3(1,1), HC3N(2-1), HC5N(9-8), HC7N(16-15), HC7N(21-20), and HC7N(23-22) transitions gives Delta V = 0.002 +/- 0.015 km/s (3 sigma C.L.). This value, when interpreted in terms of Delta mu/mu = (mu_obs - mu_lab)/mu_lab constraints the mu-variation at the level of Delta mu/mu < 2x10^{-8} (3 sigma C.L.), which is the most stringent limit on the fractional changes in mu based on radio astronomical observations. If variation of the fine-structure constant alpha is coupled with mu, then within the grand unification model one may expect locally the spacial changes |Delta alpha/...
Berengut, J C; Kava, E M
2011-01-01
Atomic microwave clocks based on hyperfine transitions, such as the caesium standard, tick with a frequency that is proportional to the magnetic moment of the nucleus. This magnetic moment varies strongly between isotopes of the same atom, while all atomic electron parameters remain the same. Therefore the comparison of two microwave clocks based on different isotopes of the same atom can be used to constrain variation of fundamental constants. In this paper we calculate the neutron and proton contributions to the nuclear magnetic moments, as well as their sensitivity to any potential quark mass variation, in a number of isotopes of experimental interest including 201,199Hg and 87,85Rb, where experiments are underway. We also include a brief treatment of the dependence of the hyperfine transitions to variation in nuclear radius, which in turn is proportional to any change in quark mass. Our calculations of expectation-values of proton and neutron spin in nuclei are also needed to interpret measurements of vio...
Berengut, J C
2010-01-01
The remarkable detection of a spatial variation in the fine-structure constant, alpha, from quasar absorption systems must be independently confirmed by complementary searches. In this letter, we discuss how terrestrial measurements of time-variation of the fundamental constants in the laboratory, meteorite data, and analysis of the Oklo nuclear reactor can be used to corroborate the spatial variation seen by astronomers. Furthermore, we show that spatial variation of the fundamental constants may be observable as spatial anisotropy in the cosmic microwave background, the accelerated expansion (dark energy), and large-scale structure of the Universe.
Effects of variation of fundamental constants from Big Bang to atomic clocks
Flambaum, Victor
2004-05-01
Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental "constants" in expanding Universe. I discuss effects of variation of the fine structure constant, strong interaction, quark mass and gravitational constant. The measurements of these variations cover the lifespan of the Universe from few minutes after Big Bang to the present time and give controversial results. There are some hints for the variations in Big Bang nucleosynthesis, quasar absorption spectra and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. A billion times enhancement of the variation effects happens in transitions between accidentally degenerate atomic energy levels.
Running vacuum in the Universe and the time variation of the fundamental constants of Nature
Energy Technology Data Exchange (ETDEWEB)
Fritzsch, Harald [Nanyang Technological University, Institute for Advanced Study, Singapore (Singapore); Universitaet Muenchen, Physik-Department, Munich (Germany); Sola, Joan [Nanyang Technological University, Institute for Advanced Study, Singapore (Singapore); Universitat de Barcelona, Departament de Fisica Quantica i Astrofisica, Barcelona, Catalonia (Spain); Universitat de Barcelona (ICCUB), Institute of Cosmos Sciences, Barcelona, Catalonia (Spain); Nunes, Rafael C. [Universidade Federal de Juiz de Fora, Dept. de Fisica, Juiz de Fora, MG (Brazil)
2017-03-15
We compute the time variation of the fundamental constants (such as the ratio of the proton mass to the electron mass, the strong coupling constant, the fine-structure constant and Newton's constant) within the context of the so-called running vacuum models (RVMs) of the cosmic evolution. Recently, compelling evidence has been provided that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance ΛCDM model. Specifically, the vacuum parameters of the RVM (i.e. those responsible for the dynamics of the vacuum energy) prove to be nonzero at a confidence level >or similar 3σ. Here we use such remarkable status of the RVMs to make definite predictions on the cosmic time variation of the fundamental constants. It turns out that the predicted variations are close to the present observational limits. Furthermore, we find that the time evolution of the dark matter particle masses should be crucially involved in the total mass variation of our Universe. A positive measurement of this kind of effects could be interpreted as strong support to the ''micro-macro connection'' (viz. the dynamical feedback between the evolution of the cosmological parameters and the time variation of the fundamental constants of the microscopic world), previously proposed by two of us (HF and JS). (orig.)
Variation of fundamental constants in space and time: theory and observations
Flambaum, V V
2008-01-01
Review of recent works devoted to the temporal and spatial variation of the fundamental constants and dependence of the fundamental constants on the gravitational potential (violation of local position invariance) is presented. We discuss the variation of the fine structure constant $\\alpha=e^2/\\hbar c$, strong interaction and fundamental masses (Higgs vacuum), e.g. the electron-to-proton mass ratio $\\mu=m_e/M_p$ or $X_e=m_e/\\Lambda_{QCD}$ and $X_q=m_q/\\Lambda_{QCD}$. We also present new results from Big Bang nucleosynthesis and Oklo natural nuclear reactor data and propose new measurements of enhanced effects in atoms, nuclei and molecules, both in quasar and laboratory spectra.
Competing bounds on the present-day time variation of fundamental constants
Dent, Thomas; Wetterich, Christof
2008-01-01
We compare the sensitivity of a recent bound on time variation of the fine structure constant from optical clocks with bounds on time varying fundamental constants from atomic clocks sensitive to the electron-to-proton mass ratio, from radioactive decay rates in meteorites, and from the Oklo natural reactor. Tests of the Weak Equivalence Principle also lead to comparable bounds on present variations of constants. The "winner in sensitivity" depends on what relations exist between the variations of different couplings in the standard model of particle physics, which may arise from the unification of gauge interactions. WEP tests are currently the most sensitive within unified scenarios. A detection of time variation in atomic clocks would favour dynamical dark energy and put strong constraints on the dynamics of a cosmological scalar field.
Competing bounds on the present-day time variation of fundamental constants
Dent, Thomas; Stern, Steffen; Wetterich, Christof
2009-04-01
We compare the sensitivity of a recent bound on time variation of the fine structure constant from optical clocks with bounds on time-varying fundamental constants from atomic clocks sensitive to the electron-to-proton mass ratio, from radioactive decay rates in meteorites, and from the Oklo natural reactor. Tests of the weak equivalence principle also lead to comparable bounds on present variations of constants. The “winner in sensitivity” depends on what relations exist between the variations of different couplings in the standard model of particle physics, which may arise from the unification of gauge interactions. Weak equivalence principle tests are currently the most sensitive within unified scenarios. A detection of time variation in atomic clocks would favor dynamical dark energy and put strong constraints on the dynamics of a cosmological scalar field.
Running vacuum in the Universe and the time variation of the fundamental constants of Nature
Fritzsch, Harald; Sola, Joan
2016-01-01
We compute the time variation of the fundamental constants (such as the ratio of the proton mass to the electron mass, the strong coupling constant, the fine structure constant and Newton's constant) within the context of the so-called running vacuum models (RVM's) of the cosmic evolution. Recently, compelling evidence has been provided showing that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance $\\Lambda$CDM model. Specifically, the vacuum parameters of the RVM (i.e. those responsible for the dynamics of the vacuum energy) prove to be nonzero at a confidence level of $\\gtrsim3\\sigma$. Here we use such remarkable status of the RVM's to make definite predictions on the cosmic time variation of the fundamental constants. It turns out that the predicted variations are close to the present observational limits. Furthermore, we find that the time variation of the dark matter particles should be necessarily involved in the total mass vari...
Stadnik, Yevgeny V; Flambaum, Victor V; Dzuba, Vladimir A
2015-01-01
We propose to search for scalar dark matter via its effects on the electromagnetic fine-structure constant and particle masses. Scalar dark matter that forms an oscillating classical field produces `slow' linear-in-time drifts and oscillating variations of the fundamental constants, while scalar dark matter that forms topological defects produces transient-in-time variations of the constants of Nature. These variations can be sought for with atomic clock, laser interferometer and pulsar timing measurements. Atomic spectroscopy and Big Bang nucleosynthesis measurements already give improved bounds on the quadratic interaction parameters of scalar dark matter with the photon, electron, and light quarks by up to 15 orders of magnitude, while Big Bang nucleosynthesis measurements provide the first such constraints on the interaction parameters of scalar dark matter with the massive vector bosons.
Variation of fundamental constants in space and time: Theory and observations
Flambaum, V. V.
2008-10-01
Review of recent works devoted to the temporal and spatialvariation of the fundamental constants and dependence of the fundamentalconstants on the gravitational potential (violation of local position invariance) is presented. We discuss the variation of the fine structure constant α=e2/ħc, strong interaction andfundamental masses (Higgs vacuum), e.g. the electron-to-proton mass ratioμ=me/Mp or Xe=me/ΛQCD and Xq=mq/ΛQCD.We also present new results from Big Bang nucleosynthesisand Oklo natural nuclear reactor data and propose new measurements of enhanced effects in atoms, nuclei and molecules, both in quasar and laboratory spectra.
Stadnik, Y V; Flambaum, V V
2015-04-24
Any slight variations in the fundamental constants of nature, which may be induced by dark matter or some yet-to-be-discovered cosmic field, would characteristically alter the phase of a light beam inside an interferometer, which can be measured extremely precisely. Laser and maser interferometry may be applied to searches for the linear-in-time drift of the fundamental constants, detection of topological defect dark matter through transient-in-time effects, and for a relic, coherently oscillating condensate, which consists of scalar dark matter fields, through oscillating effects. Our proposed experiments require either minor or no modifications of existing apparatus, and offer extensive reach into important and unconstrained spaces of physical parameters.
Sensitivity of rotational transitions in CH and CD to a possible variation of fundamental constants
de Nijs, Adrian J; Bethlem, Hendrick L
2012-01-01
The sensitivity of rotational transitions in CH and CD to a possible variation of fundamental constants has been investigated. Largely enhanced sensitivity coefficients are found for specific transitions which are due to accidental degeneracies between the different fine-structure manifolds. These degeneracies occur when the spin-orbit coupling constant is close to four times the rotational constant. CH and particularly CD match this condition closely. Unfortunately, an analysis of the transition strengths shows that the same condition that leads to an enhanced sensitivity suppresses the transition strength, making these transitions too weak to be of relevance for testing the variation of fundamental constants over cosmological time scales. We propose a test in CH based on the comparison between the rotational transitions between the e and f components of the Omega'=1/2,J=1/2 and Omega'=3/2,J=3/2 levels at 532 and 536 GHz and other rotational or Lambda-doublet transitions in CH involving the same absorbing gr...
A Different Look at Dark Energy and the Time Variation of Fundamental Constants
Energy Technology Data Exchange (ETDEWEB)
Weinstein, Marvin; /SLAC
2011-02-07
This paper makes the simple observation that a fundamental length, or cutoff, in the context of Friedmann-Lemaitre-Robertson-Walker (FRW) cosmology implies very different things than for a static universe. It is argued that it is reasonable to assume that this cutoff is implemented by fixing the number of quantum degrees of freedom per co-moving volume (as opposed to a Planck volume) and the relationship of the vacuum-energy of all of the fields in the theory to the cosmological constant (or dark energy) is re-examined. The restrictions that need to be satisfied by a generic theory to avoid conflicts with current experiments are discussed, and it is shown that in any theory satisfying these constraints knowing the difference between w and minus one allows one to predict w. It is argued that this is a robust result and if this prediction fails the idea of a fundamental cutoff of the type being discussed can be ruled out. Finally, it is observed that, within the context of a specific theory, a co-moving cutoff implies a predictable time variation of fundamental constants. This is accompanied by a general discussion of why this is so, what are the strongest phenomenological limits upon this predicted variation, and which limits are in tension with the idea of a co-moving cutoff. It is pointed out, however, that a careful comparison of the predicted time variation of fundamental constants is not possible without restricting to a particular model field-theory and that is not done in this paper.
An upper limit to the variation in the fundamental constants at redshift z = 5.2
Levshakov, S A; Boone, F; Agafonova, I I; Reimers, D; Kozlov, M G
2012-01-01
Aims. We constrain a hypothetical variation in the fundamental physical constants over the course of cosmic time. Methods. We use unique observations of the CO(7-6) rotational line and the [CI] 3P_2 - 3P_1 fine-structure line towards a lensed galaxy at redshift z = 5.2 to constrain temporal variations in the constant F = alpha^2/mu, where mu is the electron-to-proton mass ratio and alpha is the fine-structure constant. The relative change in F between z = 0 and z = 5.2, dFF = (F_obs - F_lab)/F_lab, is estimated from the radial velocity offset, dV = V_rot - V_fs, between the rotational transitions in carbon monoxide and the fine-structure transition in atomic carbon. Results. We find a conservative value dV = 1 +/- 5 km/s (1sigma C.L.), which when interpreted in terms of dFF gives dFF < 2x10^-5. Independent methods restrict the mu-variations at the level of dmm < 1x10^-7 at z = 0.7 (look-back time t_z0.7 = 6.4 Gyr). Assuming that temporal variations in mu, if any, are linear, this leads to an upper limit...
Flambaum, Victor
2016-05-01
Low-mass boson dark matter particles produced after Big Bang form classical field and/or topological defects. In contrast to traditional dark matter searches, effects produced by interaction of an ordinary matter with this field and defects may be first power in the underlying interaction strength rather than the second or fourth power (which appears in a traditional search for the dark matter). This may give a huge advantage since the dark matter interaction constant is extremely small. Interaction between the density of the dark matter particles and ordinary matter produces both `slow' cosmological evolution and oscillating variations of the fundamental constants including the fine structure constant alpha and particle masses. Recent atomic dysprosium spectroscopy measurements and the primordial helium abundance data allowed us to improve on existing constraints on the quadratic interactions of the scalar dark matter with the photon, electron and light quarks by up to 15 orders of magnitude. Limits on the linear and quadratic interactions of the dark matter with W and Z bosons have been obtained for the first time. In addition to traditional methods to search for the variation of the fundamental constants (atomic clocks, quasar spectra, Big Bang Nucleosynthesis, etc) we discuss variations in phase shifts produced in laser/maser interferometers (such as giant LIGO, Virgo, GEO600 and TAMA300, and the table-top silicon cavity and sapphire interferometers), changes in pulsar rotational frequencies (which may have been observed already in pulsar glitches), non-gravitational lensing of cosmic radiation and the time-delay of pulsar signals. Other effects of dark matter and dark energy include apparent violation of the fundamental symmetries: oscillating or transient atomic electric dipole moments, precession of electron and nuclear spins about the direction of Earth's motion through an axion condensate, and axion-mediated spin-gravity couplings, violation of Lorentz
Exploring variations in the fundamental constants with ELTs: the CODEX spectrograph on OWL
Molaro, Paolo; Murphy, Michael T.; Levshakov, Sergei A.
Cosmological variations in the fine structure constant, α, can be probed through precise velocity measurements of metallic absorption lines from intervening gas clouds seen in spectra of distant quasars. Data from the Keck/HIRES instrument support a variation in α of 6 parts per million. Such a variation would have profound implications, possibly providing a window into the extra spatial dimensions required by unified theories such as string/M-theory. However, recent results from VLT/UVES suggest no variation in α. The COsmic Dynamics EXperiment (CODEX) spectrograph currently being designed for the ESO OWL telescope (Pasquini et al. 2005) with a resolution high enough to properly resolve even the narrowest of metallic absorption lines, R > 150000, will achieve a 2-to-3 order-of-magnitude precision increase in Δα/α. This will rival the precision available from the Oklo natural fission reactor and upcoming satellite-borne atomic clock experiments. Given the vital constraints on fundamental physics possible, the ELT community must consider such a high-resolution optical spectrograph like CODEX.
Testing the variation of fundamental constants by astrophysical methods: overview and prospects
Levshakov, S A
2016-01-01
By measuring the fundamental constants in astrophysical objects one can test basic physical principles as space-time invariance of physical laws along with probing the applicability limits of the standard model of particle physics. The latest constraints on the fine structure constant alpha and the electron-to-proton mass ratio mu obtained from observations at high redshifts and in the Milky Way disk are reviewed. In optical range, the most accurate measurements have already reached the sensitivity limit of available instruments, and further improvements will be possible only with next generation of telescopes and receivers. New methods of the wavelength calibration should be realized to control systematic errors at the sub-pixel level. In radio sector, the main tasks are the search for galactic and extragalactic objects suitable for precise molecular spectroscopy as well as high resolution laboratory measurements of molecular lines to provide accurate frequency standards. The expected progress in the optical...
Exploring variations in the fundamental constants with ELTs: The CODEX spectrograph on OWL
Molaro, P; Levshakov, S; Molaro, Paolo; Murphy, Michael T.; Levshakov, Sergei
2006-01-01
Cosmological variations in the fine structure constant, alpha, can be probed through precise velocity measurements of metallic absorption lines from intervening gas clouds seen in spectra of distant quasars. Data from the Keck/HIRES instrument support a variation in alpha of 6 parts per million. Such a variation would have profound implications, possibly providing a window into the extra spatial dimensions required by unified theories such as string/M-theory. However, recent results from VLT/UVES suggest no variation in alpha. The COsmic Dynamics EXperiment (CODEX) spectrograph currently being designed for the ESO OWL telescope (Pasquini et al 2005) with a resolution high enough to properly resolve even the narrowest of metallic absorption lines, R>150,000, will achieve a 2-to-3 order-of-magnitude precision increase in Delta\\alpha/alpha. This will rival the precision available from the Oklo natural fission reactor and upcoming satellite-borne atomic clock experiments. Given the vital constraints on fundamenta...
A Different Look at Dark Energy and the Time Variation of Fundamental Constants
Weinstein, Marvin
2011-01-01
This paper makes the simple observation that a fundamental length, or cutoff, in the context of Friedmann-Lema\\^itre-Robertson-Walker (FRW) cosmology implies very different things than for a static universe. It is argued that it is reasonable to assume that this cutoff is implemented by fixing the number of quantum degrees of freedom per co-moving volume (as opposed to a Planck volume) and the relationship of the vacuum-energy of all of the fields in the theory to the cosmological constant (or dark energy) is re-examined. The restrictions that need to be satisfied by a generic theory to avoid conflicts with current experiments are discussed, and it is shown that in any theory satisfying these constraints knowing the difference between $w$ and minus one allows one to predict $\\dot{w}$. It is argued that this is a robust result and if this prediction fails the idea of a fundamental cutoff of the type being discussed can be ruled out. Finally, it is observed that, within the context of a specific theory, a co-mo...
Stadnik, Y V
2015-01-01
We outline new laser interferometer measurements to search for variation of the electromagnetic fine-structure constant $\\alpha$ and particle masses (including a non-zero photon mass). We propose a strontium optical lattice clock -- silicon single-crystal cavity interferometer as a novel small-scale platform for these new measurements. Multiple passages of a light beam inside an interferometer enhance the effects due to variation of the fundamental constants by the mean number of passages ($N_{\\textrm{eff}} \\sim 10^2$ for a large-scale gravitational-wave detector, such as LIGO, Virgo, GEO600 or TAMA300, while $N_{\\textrm{eff}} \\sim 10^5$ for a strontium clock -- silicon cavity interferometer). Our proposed laser interferometer measurements may be implemented as an extremely precise tool in the direct detection of scalar dark matter that forms an oscillating classical field or topological defects.
Type Ia Supernovae Progenitor Problem and the Variation of Fundamental Constants
Directory of Open Access Journals (Sweden)
Rybicki M.
2016-01-01
Full Text Available Cosmological observations strongly suggest our universe is the interior of an expanding black hole. If the constant mass of the universe is assumed then from the equation for Schwarzschild radius: r S = 2 Gmc it follows that proportionality constant Gc depends linearly on the universe’s radius R u , identified with r S , i.e. Gc Because the Chandrasekhar limit M Ch relates to the speed of light and to the Newton’s constant as M Ch ( c = G 3 = 2 so expansion involves gradual decrease of M Ch . In result, a single white dwarf can alone become the Type Ia supernova progenitor, which provides a complementary solution to single-degenerate and double-degenerate models for SNe Ia. Both alternative scenarios: G R u and c R are analyzed in regard of their consistence with observations, and their consequences to cosmology.
Petrov, Yu. V.; Nazarov, A. I.; Onegin, M. S.; Petrov, V. Yu.; Sakhnovsky, E. G.
2006-12-01
Using modern methods of reactor physics, we performed full-scale calculations of the Oklo natural reactor. For reliability, we used recent versions of two Monte Carlo codes: the Russian code MCU-REA and the well-known international code MCNP. Both codes produced similar results. We constructed a computer model of the Oklo reactor zone RZ2 which takes into account all details of design and composition. The calculations were performed for three fresh cores with different uranium contents. Multiplication factors, reactivities, and neutron fluxes were calculated. We also estimated the temperature and void effects for the fresh core. As would be expected, we found for the fresh core a significant difference between reactor and Maxwell spectra, which had been used before for averaging cross sections in the Oklo reactor. The averaged cross section of 62149Sm and its dependence on the shift of a resonance position Er (due to variation of fundamental constants) are significantly different from previous results. Contrary to the results of previous papers, we found no evidence of a change of the samarium cross section: a possible shift of the resonance energy is given by the limits -73⩽ΔEr⩽62 meV. Following tradition, we have used formulas of Damour and Dyson to estimate the rate of change of the fine structure constant α. We obtain new, more accurate limits of -4×10-17⩽α·/α⩽3×10-17yr-1. Further improvement of the accuracy of the limits can be achieved by taking account of the core burn-up. These calculations are in progress.
Petrov, Yu V; Onegin, M S; Petrov, V Yu; Sakhnovskii, E G; Petrov, Yu.V.
2006-01-01
Using a modern methods of reactor physics we have performed the full-scale calculations of the natural reactor Oklo. For reliability we have used the recent version of two Monte Carlo codes: the Russian code MCU REA and world wide known code MCNP (USA). Both codes produce close results. We constructed computer model of zone RZ2 of reactor Oklo which takes into account all details of design and composition. The calculations were performed for the three fresh cores with different uranium contents. Multiplication factors, reactivities and neutron fluxes were calculated. We estimated also the temperature and void effects for the fresh core. As would be expected, we have found for the fresh core a great difference between reactor spectra and Maxwell's one, which was used before for averaging cross sections in the Oklo reactor. The averaged cross section of Sm and its dependence on the shift of resonance position (due to variation of fundamental constants) are significantly different from previous results. Contrary...
Time-Varying Fundamental Constants
Olive, Keith
2003-04-01
Recent data from quasar absorption systems can be interpreted as arising from a time variation in the fine-structure constant. However, there are numerous cosmological, astro-physical, and terrestrial bounds on any such variation. These includes bounds from Big Bang Nucleosynthesis (from the ^4He abundance), the Oklo reactor (from the resonant neutron capture cross-section of Sm), and from meteoretic lifetimes of heavy radioactive isotopes. The bounds on the variation of the fine-structure constant are significantly strengthened in models where all gauge and Yukawa couplings vary in a dependent manner, as would be expected in unified theories. Models which are consistent with all data are severly challenged when Equivalence Principle constraints are imposed.
Directory of Open Access Journals (Sweden)
Bormashenko Edward
2009-01-01
Full Text Available The status of fundamental physical constants is discussed. The nature of fundamental physical constants is cleared up, based on the analysis of the Boltzmann constant. A new definition of measurable values, 'mathematical' and 'physical' numbers and fundamental physical constants is proposed. Mathematical numbers are defined as values insensitive to the choice of both units and frames of reference, whereas 'physical numbers' are dimensionless values, insensitive to transformations of units and sensitive to the transformations of the frames of reference. Fundamental constants are classified as values sensitive to transformations of the units and insensitive to transformations of the frames of reference. It is supposed that a fundamental physical constant necessarily allows diminishing the number of independent etalons in a system of units.
Stadnik, Y. V.; Flambaum, V. V.
2016-06-01
We outline laser interferometer measurements to search for variation of the electromagnetic fine-structure constant α and particle masses (including a nonzero photon mass). We propose a strontium optical lattice clock—silicon single-crystal cavity interferometer as a small-scale platform for these measurements. Our proposed laser interferometer measurements, which may also be performed with large-scale gravitational-wave detectors, such as LIGO, Virgo, GEO600, or TAMA300, may be implemented as an extremely precise tool in the direct detection of scalar dark matter that forms an oscillating classical field or topological defects.
Temporal variation of coupling constants and nucleosynthesis
Oberhummer, Heinz; Fairbairn, M; Schlattl, H; Sharma, M M
2003-01-01
We investigate the triple-alpha process and the Oklo phenomenon to obtain constraints on possible cosmological time variations of fundamental constants. Specifically we study cosmological temporal constraints for the fine structure constant and nucleon and meson masses.
Temporal variation of coupling constants and nucleosynthesis
Oberhummer, H.; Csótó, A.; Fairbairn, M.; Schlattl, H.; Sharma, M. M.
2003-05-01
We investigate the triple-alpha process and the Oklo phenomenon to obtain constraints on possible cosmological time variations of fundamental constants. Specifically we study cosmological temporal constraints for the fine structure constant and nucleon and meson masses.
The fundamental constants and quantum electrodynamics
Taylor, Barry N; Langenberg, D N
1969-01-01
Introduction ; review of experimental data ; least-squares adjustment to obtain values of the constants without QED theory ; implications for quantum electrodynamics ; final recommended set of fundamental constants ; summary and conclusions.
New Quasar Studies Keep Fundamental Physical Constant Constant
2004-03-01
Very Large Telescope sets stringent limit on possible variation of the fine-structure constant over cosmological time Summary Detecting or constraining the possible time variations of fundamental physical constants is an important step toward a complete understanding of basic physics and hence the world in which we live. A step in which astrophysics proves most useful. Previous astronomical measurements of the fine structure constant - the dimensionless number that determines the strength of interactions between charged particles and electromagnetic fields - suggested that this particular constant is increasing very slightly with time. If confirmed, this would have very profound implications for our understanding of fundamental physics. New studies, conducted using the UVES spectrograph on Kueyen, one of the 8.2-m telescopes of ESO's Very Large Telescope array at Paranal (Chile), secured new data with unprecedented quality. These data, combined with a very careful analysis, have provided the strongest astronomical constraints to date on the possible variation of the fine structure constant. They show that, contrary to previous claims, no evidence exist for assuming a time variation of this fundamental constant. PR Photo 07/04: Relative Changes with Redshift of the Fine Structure Constant (VLT/UVES) A fine constant To explain the Universe and to represent it mathematically, scientists rely on so-called fundamental constants or fixed numbers. The fundamental laws of physics, as we presently understand them, depend on about 25 such constants. Well-known examples are the gravitational constant, which defines the strength of the force acting between two bodies, such as the Earth and the Moon, and the speed of light. One of these constants is the so-called "fine structure constant", alpha = 1/137.03599958, a combination of electrical charge of the electron, the Planck constant and the speed of light. The fine structure constant describes how electromagnetic forces hold
The fundamental constants a mystery of physics
Fritzsch, Harald
2009-01-01
The speed of light, the fine structure constant, and Newton's constant of gravity — these are just three among the many physical constants that define our picture of the world. Where do they come from? Are they constant in time and across space? In this book, physicist and author Harald Fritzsch invites the reader to explore the mystery of the fundamental constants of physics in the company of Isaac Newton, Albert Einstein, and a modern-day physicist
Cosmic Time Variation of the Gravitational Constant
Tomaschitz, R
2000-01-01
A pre-relativistic cosmological approach to electromagnetism and gravitation is explored that leads to a cosmic time variation of the fundamental constants. Space itself is supposed to have physical substance, which manifests by its permeability. The scale factors of the permeability tensor induce a time variation of the fundamental constants. Atomic radii, periods, and energy levels scale in cosmic time, which results in dispersionless redshifts without invoking a space expansion. Hubble constant and deceleration parameter are reviewed in this context. The time variation of the gravitational constant at the present epoch can be expressed in terms of these quantities. This provides a completely new way to restrain the deceleration parameter from laboratory bounds on the time variation of the gravitational constant. This variation also affects the redshift dependence of angular diameters and the surface brightness, and we study in some detail the redshift scaling of the linear sizes of radio sources. The effec...
Trialogue on the number of fundamental constants
Duff, Michael J; Veneziano, Gabriele
2002-01-01
This paper consists of three separate articles on the number of fundamental dimensionful constants in physics. We started our debate in summer 1992 on the terrace of the famous CERN cafeteria. In the summer of 2001 we returned to the subject to find that our views still diverged and decided to explain our current positions. LBO develops the traditional approach with three constants, GV argues in favor of just two, while MJD advocates zero.
Environment-Dependent Fundamental Physical Constants
Terazawa, Hidezumi
2012-01-01
A theory of special inconstancy, in which some fundamental physical constants such as the fine-structure and gravitational constants may vary, is proposed in pregeometry. In the special theory of inconstancy, the \\alpha-G relation of \\alpha=3\\pi/[16ln(4\\pi/5GM_W^2)] between the varying fine-structure and gravitaional constants (where M_W is the charged weak boson mass) is derived from the hypothesis that both of these constants are related to the same fundamental length scale in nature. Furthermore, it leads to the prediction of dot{{\\alpha}}/\\alpha=(-0.8\\pm2.5)\\times10^{-14}yr^{-1} from the most precise limit of dot{G}/G=(-0.6\\pm2.0)\\times10^{-12}yr^{-1} by Thorsett, which is not only consistent with the recent observation of dot{{\\alpha}}/\\alpha=(0.5\\pm0.5)\\times10^{-14}yr^{-1} by Webb et al. but also feasible for future experimental tests. Also a theory of general inconstancy, in which any fundamental physical constants may vary, is proposed in "more general relativity", by assuming that the space-time is ...
Do the fundamental constants change with time ?
Kanekar, Nissim
2008-01-01
Comparisons between the redshifts of spectral lines from cosmologically-distant galaxies can be used to probe temporal changes in low-energy fundamental constants like the fine structure constant and the proton-electron mass ratio. In this article, I review the results from, and the advantages and disadvantages of, the best techniques using this approach, before focussing on a new method, based on conjugate satellite OH lines, that appears to be less affected by systematic effects and hence holds much promise for the future.
Nucleosynthesis and the variation of fundamental couplings
2004-01-01
We determine the influence of a variation of the fundamental ``constants'' on the predicted helium abundance in Big Bang Nucleosynthesis. The analytic estimate is performed in two parts: the first step determines the dependence of the helium abundance on the nuclear physics parameters, while the second step relates those parameters to the fundamental couplings of particle physics. This procedure can incorporate in a flexible way the time variation of several couplings within a grand unified t...
Windberger, A; Crespo López-Urrutia, J R; Bekker, H; Oreshkina, N S; Berengut, J C; Bock, V; Borschevsky, A; Dzuba, V A; Eliav, E; Harman, Z; Kaldor, U; Kaul, S; Safronova, U I; Flambaum, V V; Keitel, C H; Schmidt, P O; Ullrich, J; Versolato, O O
2015-04-17
We measure optical spectra of Nd-like W, Re, Os, Ir, and Pt ions of particular interest for studies of a possibly varying fine-structure constant. Exploiting characteristic energy scalings we identify the strongest lines, confirm the predicted 5s-4f level crossing, and benchmark advanced calculations. We infer two possible values for optical M2/E3 and E1 transitions in Ir^{17+} that have the highest predicted sensitivity to a variation of the fine-structure constant among stable atomic systems. Furthermore, we determine the energies of proposed frequency standards in Hf^{12+} and W^{14+}.
Fundamental constants and cosmic vacuum: the micro and macro connection
Fritzsch, Harald
2015-01-01
The idea that the vacuum energy density $\\rho_{\\Lambda}$ could be time dependent is a most reasonable one in the expanding Universe; in fact, much more reasonable than just a rigid cosmological constant for the entire cosmic history. Being $\\rho_{\\Lambda}=\\rho_{\\Lambda}(t)$ dynamical, it offers a possibility to tackle the cosmological constant problem in its various facets. Furthermore, for a long time (most prominently since Dirac's first proposal on a time variable gravitational coupling) the possibility that the fundamental "constants" of Nature are slowly drifting with the cosmic expansion has been continuously investigated. In the last two decades, and specially in recent times, mounting experimental evidence attests that this could be the case. In this paper, we consider the possibility that these two groups of facts might be intimately connected, namely that the observed acceleration of the Universe and the possible time variation of the fundamental constants are two manifestations of the same underlyi...
Search for Possible Variation of the Fine Structure Constant
2003-01-01
Determination of the fine structure constant alpha and search for its possible variation are considered. We focus on a role of the fine structure constant in modern physics and discuss precision tests of quantum electrodynamics. Different methods of a search for possible variations of fundamental constants are compared and those related to optical measurements are considered in detail.
Inflationary Phase with Time Varying Fundamental Constants
Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.
2002-01-01
Following Barrow, and Barrow and collaborators, we find a cosmological JBD model, with varying speed of light and varying fine structure constant, where the deceleration parameter is -1,causing acceleration of the Universe.Indeed, we have an exponential inflationary phase. Plancks time, energy, length,etc.,might have had different numerical values in the past, than those available in the litterature, due to the varying values for speed of light, and gravitational constant.
Quantum electrodynamics and the fundamental constants
Directory of Open Access Journals (Sweden)
Peter J. Mohr
2000-07-01
Full Text Available the results of critical experiments and the theoretical expressions for these results written in terms of the constants. Many of the theoretical expressions are based on quantum electrodynamics (QED, so the consistency of the comparison provides a critical test of the validity of the theory.
Constraining fundamental constants of physics with quasar absorption line systems
Petitjean, Patrick; Chand, Hum; Ivanchik, Alexander; Noterdaeme, Pasquier; Gupta, Neeraj
2009-01-01
We summarize the attempts by our group and others to derive constraints on variations of fundamental constants over cosmic time using quasar absorption lines. Most upper limits reside in the range 0.5-1.5x10-5 at the 3sigma level over a redshift range of approximately 0.5-2.5 for the fine-structure constant, alpha, the proton-to-electron mass ratio, mu, and a combination of the proton gyromagnetic factor and the two previous constants, gp(alpha^2/mu)^nu, for only one claimed variation of alpha. It is therefore very important to perform new measurements to improve the sensitivity of the numerous methods to at least <0.1x10-5 which should be possible in the next few years. Future instrumentations on ELTs in the optical and/or ALMA, EVLA and SKA pathfinders in the radio will undoutedly boost this field by allowing to reach much better signal-to-noise ratios at higher spectral resolution and to perform measurements on molecules in the ISM of high redshift galaxies.
Systematic harmonic power laws inter-relating multiple fundamental constants
Chakeres, Donald; Buckhanan, Wayne; Andrianarijaona, Vola
2017-01-01
Power laws and harmonic systems are ubiquitous in physics. We hypothesize that 2, π, the electron, Bohr radius, Rydberg constant, neutron, fine structure constant, Higgs boson, top quark, kaons, pions, muon, Tau, W, and Z when scaled in a common single unit are all inter-related by systematic harmonic powers laws. This implies that if the power law is known it is possible to derive a fundamental constant's scale in the absence of any direct experimental data of that constant. This is true for the case of the hydrogen constants. We created a power law search engine computer program that randomly generated possible positive or negative powers searching when the product of logical groups of constants equals 1, confirming they are physically valid. For 2, π, and the hydrogen constants the search engine found Planck's constant, Coulomb's energy law, and the kinetic energy law. The product of ratios defined by two constants each was the standard general format. The search engine found systematic resonant power laws based on partial harmonic fraction powers of the neutron for all of the constants with products near 1, within their known experimental precision, when utilized with appropriate hydrogen constants. We conclude that multiple fundamental constants are inter-related within a harmonic power law system.
High precision fundamental constants at the TeV scale
Moch, S; Alekhin, S; Blumlein, J; de la Cruz, L; Dittmaier, S; Dowling, M; Erler, J; Espinosa, J R; Fuster, J; Tormo, X Garcia i; Hoang, A H; Huss, A; Kluth, S; Mulders, M; Papanastasiou, A S; Piclum, J; Rabbertz, K; Schwinn, C; Schulze, M; Shintani, E; Uwer, P; Zerf, N
2014-01-01
This report summarizes the proceedings of the 2014 Mainz Institute for Theoretical Physics (MITP) scientific program on "High precision fundamental constants at the TeV scale". The two outstanding parameters in the Standard Model dealt with during the MITP scientific program are the strong coupling constant $\\alpha_s$ and the top-quark mass $m_t$. Lacking knowledge on the value of those fundamental constants is often the limiting factor in the accuracy of theoretical predictions. The current status on $\\alpha_s$ and $m_t$ has been reviewed and directions for future research have been identified.
Confronting Cosmology and New Physics with Fundamental Constants
Thompson, Rodger I
2013-01-01
The values of the fundamental constants such as $\\mu = m_P/m_e$, the proton to electron mass ratio and $\\alpha$, the fine structure constant, are sensitive to the product $\\sqrt{\\zeta_x^2(w+1)}$ where $\\zeta_x$ is a coupling constant between a rolling scalar field responsible for the acceleration of the expansion of the universe and the electromagnetic field with x standing for either $\\mu$ or $\\alpha$. The dark energy equation of state $w$ can assume values different than $-1$ in cosmologies where the acceleration of the expansion is due to a scalar field. In this case the value of both $\\mu$ and $\\alpha$ changes with time. The values of the fundamental constants, therefore, monitor the equation of state and are a valuable tool for determining $w$ as a function of redshift. In fact the rolling of the fundamental constants is one of the few definitive discriminators between acceleration due to a cosmological constant and acceleration due to a quintessence rolling scalar field. $w$ is often given in parameteri...
Direct test of the time-independence of fundamental nuclear constants using the Oklo natural reactor
Shlyakhter, A I
The positions of neutron resonances have been shown to be highly sensitive to the variation of fundamental nuclear constants. The analysis of the measured isotopic shifts in the natural fossil reactor at Oklo gives the following restrictions on the possible rates of the interaction constants variation: strong ~2x10^-19 yr^-1, electromagnetic ~5x10^-18 yr^-1, weak ~10^-12 yr^-1. These limits permit to exclude all the versions of nuclear constants contemporary variation discussed in the literature. URL: http://alexonline.info >. For more recent analyses see hep-ph/9606486, hep-ph/0205206 and astro-ph/0204069 .
Recent variations of fundamental parameters and their implications for gravitation
Dent, Thomas
2010-01-01
We compare the sensitivity of a recent bound on time variation of the fine structure constant from optical clocks with bounds on time varying fundamental constants from atomic clocks sensitive to the electron-to-proton mass ratio, from radioactive decay rates in meteorites, and from the Oklo natural reactor. Tests of the Weak Equivalence Principle also lead to comparable bounds on present time variations of constants, as well as putting the strongest limits on variations tracking the gravitational potential. For recent time variations, the "winner in sensitivity" depends on possible relations between the variations of different couplings in the standard model of particle physics. WEP tests are currently the most sensitive within scenarios with unification of gauge interactions. A detection of time variation in atomic clocks would favour dynamical dark energy and put strong constraints on the dynamics of a cosmological scalar field.
Hydrogen molecular ions for improved determination of fundamental constants
Karr, J -Ph; Koelemeij, Jeroen; Korobov, Vladimir
2016-01-01
The possible use of high-resolution rovibrational spectroscopy of the hydrogen molecular ions H + 2 and HD + for an independent determination of several fundamental constants is analyzed. While these molecules had been proposed for metrology of nuclear-to-electron mass ratios, we show that they are also sensitive to the radii of the proton and deuteron and to the Rydberg constant at the level of the current discrepancies colloquially known as the proton size puzzle. The required level of accuracy, in the 10 --12 range, can be reached both by experiments, using Doppler-free two-photon spectroscopy schemes, and by theoretical predictions. It is shown how the measurement of several well-chosen rovibrational transitions may shed new light on the proton-radius puzzle, provide an alternative accurate determination of the Rydberg constant, and yield new values of the proton-to-electron and deuteron-to-proton mass ratios with one order of magnitude higher precision.
Coupled variations of fundamental couplings and primordial nucleosynthesis
Energy Technology Data Exchange (ETDEWEB)
Coc, Alain [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, IN2P3/CNRS/UPS, Bat. 104, 91405 0rsay Campus (France); Nunes, Nelson J.; Olive, Keith A. [William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, MN 55455 (United States); Uzan, Jean-Philippe; Vangioni, Elisabeth [Institut d' Astrophysique de Paris, UMR-7095 du CNRS, Universite Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris (France)
2006-10-15
The effect of variations of the fundamental nuclear parameters on big-bang nucleosynthesis are modeled and discussed in detail taking into account the interrelations between the fundamental parameters arising in unified theories. Considering only {sup 4}He, strong constraints on the variation of the neutron lifetime, neutron-proton mass difference are set. These constraints are then translated into constraints on the time variation of the Yukawa couplings and the fine structure constant. Furthermore, we show that a variation of the deuterium binding energy is able to reconcile the {sup 7}Li abundance deduced from the WMAP analysis with its spectroscopically determined value while maintaining concordance with D and {sup 4}He. (authors)
Variation of the fine structure constant
Lipovka, Anton A
2016-01-01
In present paper we evaluate the fine structure constant variation which should take place as the Universe is expanded and its curvature is changed adiabatically. This changing of the fine structure constant is attributed to the energy lost by physical system (consist of baryonic component and electromagnetic field) due to expansion of our Universe. Obtained ratio (d alpha)/alpha = 1. 10{-18} (per second) is only five times smaller than actually reported experimental limit on this value. For this reason this variation can probably be measured within a couple of years. To argue the correctness of our approach we calculate the Planck constant as adiabatic invariant of electromagnetic field, from geometry of our Universe in the framework of the pseudo- Riemannian geometry. Finally we discuss the double clock experiment based on Al+ and Hg+ clocks carried out by T. Rosenband et al. (Science 2008). We show that in this particular case there is an error in method and this way the fine structure constant variation c...
Lorentz violation in brane cosmology, accelerated expansion and fundamental constants
Ahmadi, F; Sepangi, H R
2006-01-01
The notion of Lorentz violation in four dimensions is extended to a 5-dimensional brane-world scenario by utilizing a dynamical vector field assumed to point in the bulk direction, with Lorentz invariance holding on the brane. The cosmological consequences of this theory consisting of the time variation in the gravitational coupling $G$ and cosmological term $\\Lambda_4$ are explored. The brane evolution is addressed by studying the generalized Friedmann and Raychaudhuri equations. The behavior of the expansion scale factor is then considered for different possible scenarios where the bulk cosmological constant is zero, positive or negative.
Energy Technology Data Exchange (ETDEWEB)
Nez, F
2005-06-15
This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)
Fundamental constant observational bounds on the variability of the QCD scale
Thompson, Rodger I.
2017-06-01
Many physical theories beyond the Standard Model predict time variations of basic physics parameters. Direct measurement of the time variations of these parameters is very difficult or impossible to achieve. By contrast, measurements of fundamental constants are relatively easy to achieve, both in the laboratory and by astronomical spectra of atoms and molecules in the early universe. In this work, measurements of the proton to electron mass ratio μ and the fine structure constant α are combined to place mildly model-dependent limits on the fractional variation of the quantum chromodynamic scale and the sum of the fractional variations of the Higgs vacuum expectation value (VEV) and the Yukawa couplings on time-scales of more than half the age of the universe. The addition of another model parameter allows the fractional variation of the Higgs VEV and the Yukawa couplings to be computed separately. Limits on their variation are found at the level of less than 5 × 10-5 over the past 7 Gyr. A model-dependent relation between the expected fractional variation of α relative to μ tightens the limits to 10-7 over the same time span. Limits on the present day rate of change of the constants and parameters are then calculated using slow roll quintessence. A primary result of this work is that studies of the dimensionless fundamental constants such as α and μ, whose values depend on the values of the physics parameters, are excellent monitors of the limits on the time variation of these parameters.
Fine Structure Constant: Theme With Variations
Bezerra, V B; Muniz, C R; Tahim, M O; Vieira, H S
2016-01-01
In this paper, we study the spatial variation of the fine structure constant $\\alpha$ due to the presence of a static and spherically symmetric gravitational source. The procedure consists of calculating the solution including the energy eigenvalues of a massive scalar field around that source, considering the weak-field regimen, which yields the gravitational analog of the atomic Bohr levels. From this result, we obtain several values for the effective $\\alpha$ by considering some scenarios of semi-classical and quantum gravities. Constraints on the parameters of the involved theories are calculated from astrophysical observations of the white dwarf emission spectra. Such constraints are compared with those ones obtained in the literature.
Can Dark Matter Induce Cosmological Evolution of the Fundamental Constants of Nature?
Stadnik, Y V; Flambaum, V V
2015-11-13
We demonstrate that massive fields, such as dark matter, can directly produce a cosmological evolution of the fundamental constants of nature. We show that a scalar or pseudoscalar (axionlike) dark matter field ϕ, which forms a coherently oscillating classical field and interacts with standard model particles via quadratic couplings in ϕ, produces "slow" cosmological evolution and oscillating variations of the fundamental constants. We derive limits on the quadratic interactions of ϕ with the photon, electron, and light quarks from measurements of the primordial (4)He abundance produced during big bang nucleosynthesis and recent atomic dysprosium spectroscopy measurements. These limits improve on existing constraints by up to 15 orders of magnitude. We also derive limits on the previously unconstrained linear and quadratic interactions of ϕ with the massive vector bosons from measurements of the primordial (4)He abundance.
Observational Constraints on $f(T)$ gravity from varying fundamental constants
Nunes, Rafael C; Pan, Supriya; Saridakis, Emmanuel N
2016-01-01
We use observations related to the variation of fundamental constants, in order to impose constraints on the viable and most used $f(T)$ gravity models. In particular, for the fine-structure constant we use direct measurements obtained by different spectrographic methods, while for the effective Newton's constant we use a model-dependent reconstruction, using direct observational Hubble parameter data, in order to investigate its temporal evolution. We consider two $f(T)$ models and we quantify their deviation from $\\Lambda$CDM cosmology through a sole parameter. Our analysis reveals that this parameter can be slightly different from its $\\Lambda$CDM value, however the best-fit value is very close to the $\\Lambda$CDM one. Hence, $f(T)$ gravity is consistent with observations, nevertheless, as every modified gravity, it may exhibit only small deviations from $\\Lambda$CDM cosmology, a feature that must be taken into account in any $f(T)$ model-building.
Observational constraints on f(T) gravity from varying fundamental constants
Energy Technology Data Exchange (ETDEWEB)
Nunes, Rafael C.; Bonilla, Alexander [Universidade Federal de Juiz de Fora, Departamento de Fisica, Juiz de Fora, MG (Brazil); Pan, Supriya [Indian Institute of Science Education and Research, Kolkata, Department of Physical Sciences, Mohanpur, West Bengal (India); Saridakis, Emmanuel N. [Pontificia Universidad de Catolica de Valparaiso, Instituto de Fisica, Valparaiso (Chile); National Technical University of Athens, Physics Division, Athens (Greece); Baylor University, CASPER, Physics Department, Waco, TX (United States)
2017-04-15
We use observations related to the variation of fundamental constants, in order to impose constraints on the viable and most used f(T) gravity models. In particular, for the fine-structure constant we use direct measurements obtained by different spectrographic methods, while for the effective Newton constant we use a model-dependent reconstruction, using direct observational Hubble parameter data, in order to investigate its temporal evolution. We consider two f(T) models and we quantify their deviation from Λ CDM cosmology through a sole parameter. Our analysis reveals that this parameter can be slightly different from its Λ CDM value, however, the best-fit value is very close to the Λ CDM one. Hence, f(T) gravity is consistent with observations, nevertheless, as every modified gravity, it may exhibit only small deviations from Λ CDM cosmology, a feature that must be taken into account in any f(T) model-building. (orig.)
CODATA Recommended Values of the Fundamental Physical Constants: 2014*
Mohr, Peter J.; Newell, David B.; Taylor, Barry N.
2016-12-01
This paper gives the 2014 self-consistent set of values of the constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA). These values are based on a least-squares adjustment that takes into account all data available up to 31 December 2014. Details of the data selection and methodology of the adjustment are described. The recommended values may also be found at http://physics.nist.gov/constants.
CODATA Recommended Values of the Fundamental Physical Constants: 2014
Mohr, Peter J; Taylor, Barry N
2015-01-01
This report gives the 2014 self-consistent set of values of the constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA). These values are based on a least-squares adjustment that takes into account all data available up to 31 December 2014. The recommended values may also be found on the World Wide Web at physics.nist.gov/constants.
CODATA Recommended Values of the Fundamental Physical Constants: 2010
Mohr, Peter J; Newell, David B
2012-01-01
This paper gives the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into account the data considered in the 2006 adjustment as well as the data that became available from 1 January 2007, after the closing date of that adjustment, until 31 December 2010, the closing date of the new adjustment. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2010 set replaces the previously recommended 2006 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.
Current Status of the Problem of Cosmological Variability of Fundamental Physical Constants
Varshslovich, D.A.; Ivanchik, A.V.; Orlov, A.V.; Potekhin, A.Y.; Petitjean, P.
We review the current status of the problem of cosmological variability of fundamental physical constants, provided by modern laboratory experiments, Oklo phenomena analysis, and especially astronomical observations.
Can we test Dark Energy with Running Fundamental Constants ?
Doran, M
2004-01-01
We investigate a link between the running of the fine structure constant $\\alpha$ and a time evolving scalar dark energy field. Employing a versatile parameterization for the equation of state, we exhaustively cover the space of dark energy models. Under the assumption that the change in $\\alpha$ is to first order given by the evolution of the Quintessence field, we show that current Oklo, Quasi Stellar Objects and Equivalence Principle observations restrict the model parameters considerably stronger than observations of the Cosmic Microwave Background, Large Scale Structure and Supernovae Ia combined.
Can we test dark energy with running fundamental constants?
Doran, Michael
2005-04-01
We investigate a link between the running of the fine structure constant α and a time evolving scalar dark energy field. Employing a versatile parametrization for the equation of state, we exhaustively cover the space of dark energy models. Under the assumption that the change in α is to first order given by the evolution of the quintessence field, we show that current Oklo, quasi-stellar object and equivalence principle observations restrict the model parameters considerably more strongly than observations of the cosmic microwave background, large scale structure and supernovae Ia combined.
Dependence of the triple-alpha process on the fundamental constants of nature
Epelbaum, Evgeny; Lähde, Timo A; Lee, Dean; Meißner, Ulf-G
2013-01-01
We present an ab initio calculation of the quark mass dependence of the ground state energies of ^4He, ^8Be and ^{12}C, and of the energy of the Hoyle state in ^{12}C. These investigations are performed within the framework of lattice chiral Effective Field Theory. We address the sensitivity of the production rate of carbon and oxygen in red giant stars to the fundamental constants of nature by considering the impact of variations in the light quark masses and the electromagnetic fine-structure constant on the reaction rate of the triple-alpha process. As carbon and oxygen are essential to life as we know it, we also discuss the implications of our findings for an anthropic view of the Universe. We find strong evidence that the physics of the triple-alpha process is driven by alpha clustering, and that shifts in the fundamental parameters at the \\simeq 2 - 3 % level are unlikely to be detrimental to the development of life. Tolerance against much larger changes cannot be ruled out at present, given the relati...
Dependence of the triple-alpha process on the fundamental constants of nature
Energy Technology Data Exchange (ETDEWEB)
Epelbaum, Evgeny; Krebs, Hermann [Ruhr-Universitaet Bochum, Institut fuer Theoretische Physik II, Bochum (Germany); Laehde, Timo A. [Forschungszentrum Juelich, Institut fuer Kernphysik, Institute for Advanced Simulation, Juelich (Germany); Lee, Dean [North Carolina State University, Department of Physics, Raleigh, NC (United States); Meissner, Ulf G. [Forschungszentrum Juelich, Institut fuer Kernphysik, Institute for Advanced Simulation, Juelich (Germany); Forschungszentrum Juelich, JARA - High Performance Computing, Juelich (Germany); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany)
2013-07-15
We present an ab initio calculation of the quark mass dependence of the ground state energies of {sup 4}He, {sup 8}Be and {sup 12}C, and of the energy of the Hoyle state in {sup 12}C. These investigations are performed within the framework of lattice chiral Effective Field Theory. We address the sensitivity of the production rate of carbon and oxygen in red giant stars to the fundamental constants of nature by considering the impact of variations in the light quark masses and the electromagnetic fine-structure constant on the reaction rate of the triple-alpha process. As carbon and oxygen are essential to life as we know it, we also discuss the implications of our findings for an anthropic view of the Universe. We find strong evidence that the physics of the triple-alpha process is driven by alpha clustering, and that shifts in the fundamental parameters at the {approx_equal} 2-3% level are unlikely to be detrimental to the development of life. Tolerance against much larger changes cannot be ruled out at present, given the relatively limited knowledge of the quark mass dependence of the two-nucleon S -wave scattering parameters. Lattice QCD is expected to provide refined estimates of the scattering parameters in the future. (orig.)
The variation of the fine structure constant: testing the dipole model with thermonuclear supernovae
Kraiselburd, Lucila; Negrelli, Carolina; Berro, Enrique García
2014-01-01
The large-number hypothesis conjectures that fundamental constants may vary. Accordingly, the spacetime variation of fundamental constants has been an active subject of research for decades. Recently, using data obtained with large telescopes a phenomenological model in which the fine structure constant might vary spatially has been proposed. We test whether this hypothetical spatial variation of {\\alpha}, which follows a dipole law, is compatible with the data of distant thermonuclear supernovae. Unlike previous works, in our calculations we consider not only the variation of the luminosity distance when a varying {\\alpha} is adopted, but we also take into account the variation of the peak luminosity of Type Ia supernovae resulting from a variation of {\\alpha}. This is done using an empirical relation for the peak bolometric magnitude of thermonuclear supernovae that correctly reproduces the results of detailed numerical simulations. We find that there is no significant difference between the several phenome...
Time-variability of the coupling constants of fundamental particles and Oklo phenomena
Energy Technology Data Exchange (ETDEWEB)
Fujii, Yasunori [Nihon Fukushi Univ., Handa, Aichi (Japan); Iwamoto, Akira; Hidaka, Hiroshi
2000-09-01
About 60 years ago, Dirac, P.A.M. presented that gravitational constant was not a constant but varied with a time in universe. As it has not obtained any determining proof experimentally, a fundamental concept on physical constants was disturbed since then, which has been succeeded to trials on the present integral theory. In special, some interesting researches on what is called coupling constants of fundamental particles, such as if fundamental charge of an electron changes actually, are continued. As proof on this change was not established, the observing and experimental upper values contain some important suggestions. The most serious result as its upper limit was obtained as well by an investigation on a surprising fact (a natural reactor) that uranium naturally reached a criticality at a place (Oklo) on the earth two billion years ago. Here were introduced on some their recent researches. (G.K.)
Base units of the SI, fundamental constants and modern quantum physics.
Bordé, Christian J
2005-09-15
Over the past 40 years, a number of discoveries in quantum physics have completely transformed our vision of fundamental metrology. This revolution starts with the frequency stabilization of lasers using saturation spectroscopy and the redefinition of the metre by fixing the velocity of light c. Today, the trend is to redefine all SI base units from fundamental constants and we discuss strategies to achieve this goal. We first consider a kinematical frame, in which fundamental constants with a dimension, such as the speed of light c, the Planck constant h, the Boltzmann constant k(B) or the electron mass m(e) can be used to connect and redefine base units. The various interaction forces of nature are then introduced in a dynamical frame, where they are completely characterized by dimensionless coupling constants such as the fine structure constant alpha or its gravitational analogue alpha(G). This point is discussed by rewriting the Maxwell and Dirac equations with new force fields and these coupling constants. We describe and stress the importance of various quantum effects leading to the advent of this new quantum metrology. In the second part of the paper, we present the status of the seven base units and the prospects of their possible redefinitions from fundamental constants in an experimental perspective. The two parts can be read independently and they point to these same conclusions concerning the redefinitions of base units. The concept of rest mass is directly related to the Compton frequency of a body, which is precisely what is measured by the watt balance. The conversion factor between mass and frequency is the Planck constant, which could therefore be fixed in a realistic and consistent new definition of the kilogram based on its Compton frequency. We discuss also how the Boltzmann constant could be better determined and fixed to replace the present definition of the kelvin.
Can dark matter induce cosmological evolution of the fundamental constants of Nature?
Stadnik, Y V
2015-01-01
Traditional theories, which predict the cosmological evolution of the fundamental constants of Nature, assume that the underlying fields, which give rise to this evolution, are unnaturally light. We demonstrate that massive fields, such as dark matter, also directly produce a cosmological evolution of the fundamental constants. We consider the specific model of a scalar dark matter field $\\phi$, which interacts with Standard Model particles via quadratic couplings in $\\phi$. In this particular model, cosmological evolution of the fundamental constants arises due to changes in $\\left$ in time and space. The most stringent constraints on the physical parameters of the present model come from measurements of the neutron-proton mass difference at the time of the weak interaction freeze-out.
Microwave and submillimeter molecular transitions and their dependence on fundamental constants
Energy Technology Data Exchange (ETDEWEB)
Kozlov, Mikhail G. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); St. Petersburg Electrotechnical University ' ' LETI' ' , St. Petersburg (Russian Federation); Levshakov, Sergei A. [St. Petersburg Electrotechnical University ' ' LETI' ' , St. Petersburg (Russian Federation); Ioffe Physical-Technical Institute, St. Petersburg (Russian Federation)
2013-07-15
Microwave and submillimeter molecular transition frequencies between nearly degenerated rotational levels, tunneling transitions, and mixed tunneling-rotational transitions show an extremely high sensitivity to the values of the fine-structure constant, {alpha}, and the electron-to-proton mass ratio, {mu}. This review summarizes the theoretical background on quantum-mechanical calculations of the sensitivity coefficients of such transitions to tiny changes in {alpha} and {mu} for a number of molecules which are usually observed in Galactic and extragalactic sources, and discusses the possibility of testing the space- and time-invariance of fundamental constants through comparison between precise laboratory measurements of the molecular rest frequencies and their astronomical counterparts. In particular, diatomic radicals CH, OH, NH{sup +}, and a linear polyatomic radical C{sub 3}H in {Pi} electronic ground state, polyatomic molecules NH{sub 3}, ND{sub 3}, NH{sub 2}D, NHD{sub 2}, H{sub 2}O{sub 2}, H{sub 3}O{sup +}, CH{sub 3}OH, and CH{sub 3}NH{sub 2} in their tunneling and tunneling-rotational modes are considered. It is shown that sensitivity coefficients strongly depend on the quantum numbers of the corresponding transitions. This can be used for astrophysical tests of Einstein's Equivalence Principle all over the Universe at an unprecedented level of sensitivity of 10{sup -9}, which is a limit three to two orders of magnitude lower as compared to the current constraints on cosmological variations of {alpha} and {mu}: {Delta}{alpha}/{alpha} < 10{sup -6}, {Delta} {mu} / {mu} < 10{sup -7}. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Modernizing the SI: implications of recent progress with the fundamental constants
Fletcher, Nick; Stock, Michael; Milton, Martin JT
2015-01-01
Recent proposals to re-define some of the base units of the SI make use of definitions that refer to fixed numerical values of certain constants. We review these proposals in the context of the latest results of the least-squares adjustment of the fundamental constants and against the background of the difficulty experienced with communicating the changes. We show that the benefit of a definition of the kilogram made with respect to the atomic mass constant (mu) may now be significantly stronger than when the choice was first considered 10 years ago.
Comments on redefinition of SI units based on fundamental physical constants with fixed values
Khruschov, V V
2011-01-01
Advantages and disadvantages of fixation of fundamental physical constants' values for definition of SI units are considered. The case with a new definition of the mass unit on the base of a fixed value of the Avogadro constant is studied in detail. Criteria on choosing of a optimum FPC set with fixed values for the redefinition of the SI units are suggested. The minimal optimum FPC set that is consistent with the criteria is presented. The set comprises the speed of light, the constant of the ground state hyperfine transition of the caesium-133 atom, the Avogadro constant, the mass of the carbon-12 atom and the absolute magnitude of the electron charge. Comment on the redefinition of the kelvin is also made.
Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.; King, J. A.; Kozlov, M. G.; Murphy, M. T.; Webb, J. K.
2010-11-01
Current theories that seek to unify gravity with the other fundamental interactions suggest that spatial and temporal variation of fundamental constants is a possibility, or even a necessity, in an expanding Universe. Several studies have tried to probe the values of constants at earlier stages in the evolution of the Universe, using tools such as big-bang nucleosynthesis, the Oklo natural nuclear reactor, quasar absorption spectra, and atomic clocks (see, e.g. Flambaum & Berengut (2009)).
Variation of the fine structure constant and the electron mass at early Universe
Scóccola, Claudia G
2009-01-01
In this thesis, we focus on the study of the variation of the electron mass $m_e$, and the fine structure constant $\\alpha$, at different cosmic times. We analyze the details of the recombination physics, including helium recombination, in order to find the dependences of the physical quantities on the fundamental constants. Using up-to-date CMB data, and the final 2dFGRS power spectrum, we set limits to the possible variation of the constants at recombination. We analyze the variation of $\\alpha$ and $m_e$ independently, and the case in which both variations are allowed, fitting also a set of cosmological parameters. We find a fenomenological relationship between the variation of $\\alpha$ and the variation of $m_e$, between decoupling and present time. We analyze the Barrow-Magueijo fenomenological model, which propose a variation in the electron mass induced by changes in a space-time scalar field. We present improved solutions and we estimate the model parameters using bounds on the variation of the electr...
The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature
Energy Technology Data Exchange (ETDEWEB)
Lamoreaux, Steve (LANL)
2005-11-07
Natural nuclear reactors? Changes in the speed of light? If either of these concepts seem implausible to you now they certainly won't once Dr. Steve Lamoreaux (LANL) delivers his SLAC Colloquium lecture in the Panofsky Auditorium on November 7th at 4:15 pm entitled The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature. This lecture is a rare opportunity to learn not only about Oklo's incredible natural nuclear reactors but also to gain understanding about how the present-day study of these sites may alter our understanding of fundamental constants such as the speed of light. This event is a must-see for the curious!
Spectroscopy of antiprotonic helium atoms and its contribution to the fundamental physical constants
Hayano, R S
2010-01-01
Proceedings of the Japan Academy, Series B Vol. 86 (2010) No. 1 P 1-10 Language: Next Article http://dx.doi.org/10.2183/pjab.86.1 JST.JSTAGE/pjab/86.1 Reviews Spectroscopy of antiprotonic helium atoms and its contribution to the fundamental physical constants Ryugo S. HAYANO1) 1) Department of Physics, The University of Tokyo Released 2010/01/14 Keywords: antiproton, CERN, fundamental physical constants, laser spectroscopy Full Text PDF [1604K] Abstracts References(25) Antiprotonic helium atom, a metastable neutral system consisting of an antiproton, an electron and a helium nucleus, was serendipitously discovered, and has been studied at CERN’s antiproton decelerator facility. Its transition frequencies have recently been measured to nine digits of precision by laser spectroscopy. By comparing these experimental results with three-body QED calculations, the antiproton-to-electron massratio was determined as 1836.152674(5). This result contributed to the CODATA recommended val...
The New SI and fundamental constants: different meanings assigned to the same data
Pavese, Franco
2016-01-01
This note discusses the role of fundamental constants in the proposed New SI formulation of the definition of the International System of Units, namely in the present official documents and in some relevant literature. The meaning assigned to their use is found substantially different even among the advocates of the proposal. Some reasons are discussed why it is urgent that this basic issue is clarified.
Constraints on Alternate Universes: Stars and habitable planets with different fundamental constants
Adams, Fred C
2015-01-01
This paper develops constraints on the values of the fundamental constants that allow universes to be habitable. We focus on the fine structure constant $\\alpha$ and the gravitational structure constant $\\alpha_G$, and find the region in the $\\alpha$-$\\alpha_G$ plane that supports working stars and habitable planets. This work is motivated, in part, by the possibility that different versions of the laws of physics could be realized within other universes. The following constraints are enforced: [A] long-lived stable nuclear burning stars exist, [B] planetary surface temperatures are hot enough to support chemical reactions, [C] stellar lifetimes are long enough to allow biological evolution, [D] planets are massive enough to maintain atmospheres, [E] planets are small enough in mass to remain non-degenerate, [F] planets are massive enough to support sufficiently complex biospheres, [G] planets are smaller in mass than their host stars, and [H] stars are smaller in mass than their host galaxies. This paper del...
Time Variation of the Fine Structure Constant Driven by Quintessence
Anchordoqui, L A; Anchordoqui, Luis; Goldberg, Haim
2003-01-01
There are indications from the study of quasar absorption spectra that the fine structure constant $\\alpha$ may have been measurably smaller for redshifts $z>2.$ Analyses of other data ($^{149}$Sm fission rate for the Oklo natural reactor, variation of $^{187}$Re $\\beta$-decay rate in meteorite studies, atomic clock measurements) which probe variations of $\\alpha$ in the more recent past imply much smaller deviations from its present value. In this work we tie the variation of $\\alpha$ to the evolution of the quintessence field proposed by Albrecht and Skordis, and show that agreement with all these data, as well as consistency with WMAP observations, can be achieved for a range of parameters. Some definite predictions follow for upcoming space missions searching for violations of the equivalence principle.
Time variation of the fine structure constant driven by quintessence
Anchordoqui, Luis; Goldberg, Haim
2003-10-01
There are indications from the study of quasar absorption spectra that the fine structure constant α may have been measurably smaller for redshifts z>2. Analyses of other data (149Sm fission rate for the Oklo natural reactor, variation of 187Re β-decay rate in meteorite studies, atomic clock measurements) which probe variations of α in the more recent past imply much smaller deviations from its present value. In this work we tie the variation of α to the evolution of the quintessence field proposed by Albrecht and Skordis, and show that agreement with all these data, as well as consistency with Wilkinson Microwave Anisotropy Probe observations, can be achieved for a range of parameters. Some definite predictions follow for upcoming space missions searching for violations of the equivalence principle.
Constraints on the Variations of the Fundamental Couplings
Olive, Keith A; Qian, Y Z; Coc, A; Cassé, M; Vangioni-Flam, E; Olive, Keith A.; Pospelov, Maxim; Qian, Yong-Zhong; Coc, Alain; Casse, Michel; Vangioni-Flam, Elisabeth
2002-01-01
We reconsider several current bounds on the variation of the fine-structure constant in models where all gauge and Yukawa couplings vary in an interdependent manner, as would be expected in unified theories. In particular, we re-examine the bounds established by the Oklo reactor from the resonant neutron capture cross-section of 149Sm. By imposing variations in \\Lambda_{QCD} and the quark masses, as dictated by unified theories, the corresponding bound on the variation of the fine-structure constant can be improved by about 2 orders of magnitude in such theories. In addition, we consider possible bounds on variations due to their effect on long lived \\alpha- and \\beta-decay isotopes, particularly 147Sm and 187Re. We obtain a strong constraint on \\Delta \\alpha / \\alpha, comparable to that of Oklo but extending to a higher redshift corresponding to the age of the solar system, from the radioactive life-time of 187Re derived from meteoritic studies. We also analyze the astrophysical consequences of perturbing th...
Constraints on the variations of the fundamental couplings
Olive, Keith A.; Pospelov, Maxim; Qian, Yong-Zhong; Coc, Alain; Cassé, Michel; Vangioni-Flam, Elisabeth
2002-08-01
We reconsider several current bounds on the variation of the fine-structure constant in models where all gauge and Yukawa couplings vary in an interdependent manner, as would be expected in unified theories. In particular, we reexamine the bounds established by the Oklo reactor from the resonant neutron capture cross section of 149Sm. By imposing variations in ΛQCD and the quark masses, as dictated by unified theories, the corresponding bound on the variation of the fine-structure constant can be improved by about 2 orders of magnitude in such theories. In addition, we consider possible bounds on variations due to their effect on long lived α- and β-decay isotopes, particularly 147Sm and 187Re. We obtain a strong constraint on Δα/α, comparable to that of Oklo but extending to a higher redshift corresponding to the age of the solar system, from the radioactive lifetime of 187Re derived from meteoritic studies. We also analyze the astrophysical consequences of perturbing the decay Q values on bound state β decays operating in the s process.
Fine structure constant variation or space-time anisotropy?
Chang, Zhe; Li, Xin
2011-01-01
Recent observations on quasar absorption spectra supply evidences for variation of fine structure constant $\\alpha$. In this paper, we propose another interpretation of the observational data on quasar absorption spectra: a scenario with space-time inhomogeneity and anisotropy but uniform fine structure constant. Maybe the space-time is characterized by Finsler geometry instead of Riemann one. Finsler geometry admits less symmetries than Riemann geometry does. We investigate the Finslerian geodesic equations in Randers space-time (a special Finsler space-time). It is found that the cosmological redshift in this space-time is deviated from the one in general relativity. The modification term to redshift could be generally revealed as a monopole plus dipole function about space-time locations and directions. We suggest that this modification corresponds to the observed spatial monopole and Australian Dipole in quasar absorption spectra.
Atomic Clocks and Variations of the FIne Structure Constant
Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute
1995-01-01
We describe a new test for possible variations of the fine structure constant alpha by comparisons of rates between clocks based on hyperfine transitions in alkali atoms with different atomic number Z. H-maser, Cs, and Hg(+) clocks have a different dependence on alpha via relativistic contributions of order (Z-alpha)(sup 2). Recent H-maser vs Hg(+) clock comparison data improve laboratory limits on a time variation by 100-fold to give dot-alpha less than or equal to 3.7 x 10(exp -14)/yr. Future laser cooled clocks (Be(+), Rb, Cs, Hg(+), etc.), when compared, will yield the most sensitive of all tests for dot-alpha/alpha.
Higgs potential from extended Brans–Dicke theory and the time-evolution of the fundamental constants
Solà, Joan; Karimkhani, Elahe; Khodam-Mohammadi, A.
2017-01-01
Despite the enormous significance of the Higgs potential in the context of the standard model of electroweak interactions and in grand unified theories, its ultimate origin is fundamentally unknown and must be introduced by hand in accordance with the underlying gauge symmetry and the requirement of renormalizability. Here we propose a more physical motivation for the structure of the Higgs potential, which we derive from a generalized Brans–Dicke (BD) theory containing two interacting scalar fields. One of these fields is coupled to curvature as in the BD formulation, whereas the other is coupled to gravity both derivatively and non-derivatively through the curvature scalar and the Ricci tensor. By requiring that the cosmological solutions of the model are consistent with observations, we show that the effective scalar field potential adopts the Higgs potential form with a mildly time-evolving vacuum expectation value. This residual vacuum dynamics could be responsible for the possible time variation of the fundamental constants, and is reminiscent of former Bjorken’s ideas on the cosmological constant problem.
Ivanchik, A V; Varshalovich, D A
1999-01-01
Endeavours of the unification of the four fundamental interactions have resulted in a development of theories having cosmological solutions in which low-energy limits of fundamental physical constants vary with time. The validity of such theoretical models should be checked by comparison of the theoretical predictions with observational and experimental bounds on possible time-dependences of the fundamental constants. Based on high-resolution measurements of quasar spectra, we obtain the following direct limits on the average rate of the cosmological time variation of the fine-structure constant limit, and |\\dot{\\alpha}/\\alpha| < 3.1 \\times 10^{-14} yr^{-1} is the most conservative limit. Analogous estimates published previously, as well as other contemporary tests for possible variations of \\alpha (those based on the "Oklo phenomenon", on the primordial nucleosynthesis models, and others) are discussed and compared with the present upper limit. We argue that the present result is the most conservative one...
Quantum gravity, Clifford algebras, fuzzy set theory and the fundamental constants of nature
Energy Technology Data Exchange (ETDEWEB)
El Naschie, M.S
2004-05-01
In a recent paper entitled 'Quantum gravity from descriptive set theory', published in Chaos, Solitons and Fractals, we considered following the P-adic quantum theory, the possibility of abandoning the Archimedean axiom and introducing a fundamental physical limitation on the smallest length in quantum spacetime. Proceeding that way we arrived at the conclusion that maximising the Hawking-Bekenstein informational content of spacetime makes the existence of a transfinite geometry for physical 'spacetime' plausible or even inevitable. Subsequently we introduced a mathematical description of a transfinite, non-Archimedean geometry using descriptive set theory where a similar conclusion regarding the transfiniteness of quantum spacetime may be drawn from the existence of the Unruh temperature. In particular we introduced a straight forward logarithmic gauge transformation linking, as far as we are aware for the first time, classical gravity with the electroweak via a version of informational entropy. That way we found using {epsilon}{sup ({infinity}}{sup )} and complexity theory that {alpha}-bar{sub G}=(2){sup {alpha}-bar{sub ew}}{sup -1}=1.7x10{sup 38} where {alpha}-bar{sub G} is the dimensionless Newton gravity constant and {alpha}-bar{sub ew}=128 is the fine structure constant at the electroweak unification scale. The present work is concerned with more or less the same category of fundamental questions pertinent to quantum gravity. However we switch our mathematical apparatus to a combination of Clifford algebras and set theory. In doing that, the central and vital role of the work of D. Finkelstein becomes much more tangible and clearer than in most of our previous works.
Investigation of the fundamental constants stability based on the reactor Oklo burn-up analysis
Onegin, M S
2014-01-01
New severe constraints on the variation of the fine structure constant have been obtained from reactor Oklo analysis in our previous work. We investigate here how these constraints confine the parameter of BSBM model of varying $\\alpha$. Integrating the coupled system of equations from the Big Bang up to the present time and taking into account the Oklo limits we have obtained the following margin on the combination of the parameters of BSBM model: $$ |\\zeta_m (\\frac{l}{l_{pl}})^2|<6\\cdot 10^{-7}, $$ where $l_{pl}=(\\frac{G\\hbar}{c^3})^{\\frac{1}{2}} \\approx 1.6 \\cdot 10^{-33}$ cm is a Plank length and $l$ is the characteristic length of the BSBM model. The natural value of the parameter $\\zeta_m$ - the fraction of electromagnetic energy in matter - is about $10^{-4}$. As a result it is followed from our analysis that the characteristic length $l$ of BSBM theory should be considerably smaller than the Plank length to fulfill the Oklo constraints on $\\alpha$ variation.
Measuring Changes in the Fundamental Constants with Redshifted Radio Absorption Lines
Curran, S J; Darling, J K
2004-01-01
Strong evidence has recently emerged for a variation in the fine structure constant, $\\alpha\\equiv e^2/\\hbar c$, over the history of the Universe. This was concluded from a detailed study of the relative positions of redshifted optical quasar absorption spectra. However, {\\it radio} absorption lines at high redshift offer a much higher sensitivity to a cosmological change in $\\alpha$ than optical lines. Furthermore, through the comparison of various radio transitions, \\HI, OH and millimetre molecular (e.g. CO) lines, any variations in the proton g-factor, $g_p$, and the ratio of electron/proton masses, $\\mu\\equiv m_e/m_p$, may also be constrained. Presently, however, systems exhibiting redshifted radio lines are rare with the bias being towards those associated with optically selected QSOs. With its unprecedented sensitivity, large bandwidth and wide field of view, the SKA will prove paramount in surveying the sky for absorbers unbiased by dust extinction. This is expected to yield whole new samples of \\HI ~a...
Françoise Benz
2002-01-01
17, 18, 19 , 21 June LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 Low Energy Experiments that Measure Fundamental Constants and Test Basic Symmetries by G. GABRIELSE / Professor of Physics and Chair of the Harvard Physics Department, Spokesperson for the ATRAP Collaboration Lecture 1: Particle Traps: the World's Tiniest Accelerators A single elementary particle, or a single ion, can be confined in a tiny accelerator called a particle trap. A single electron was held this way for more than ten months, and antiprotons for months. Mass spectroscopy of exquisite precision is possible with such systems. CERN's TRAP Collaboration thereby compared the charge-to-mass ratios of the antiproton and proton to a precision of 90 parts per trillion, by far the most stringent CPT test done with a baryon system. The important ratio of the masses of the electron and proton have been similarly measured, as have a variety of ions masses, and the neutron mass is most accurately known from such measurements. An i...
Variational principles of continuum mechanics. Vol. 1. Fundamentals
Energy Technology Data Exchange (ETDEWEB)
Berdichevsky, Victor L. [Wayne State Univ., Detroit, MI (United States). Dept. of Mechanical Engineering
2009-07-01
The book reviews the two features of the variational approach: its use as a universal tool to describe physical phenomena and as a source for qualitative and quantitative methods of studying particular problems. Berdichevsky's work differs from other books on the subject in focusing mostly on the physical origin of variational principles as well as establishing their interrelations. For example, the Gibbs principles appear as a consequence of the Einstein formula for thermodynamic fluctuations rather than as the first principles of the theory of thermodynamic equilibrium. Mathematical issues are considered as long as they shed light on the physical outcomes and/or provide a useful technique for the direct study of variational problems. In addition, a thorough account of variational principles discovered in various branches of continuum mechanics is given. In this book, the first volume, the author covers the variational principles for systems with a finite number of degrees of freedom; the variational principles of thermodynamics; the basics of continuum mechanics; the variational principles for classical models of continuum mechanics, such as elastic and plastic bodies, and ideal and viscous fluids; and direct methods of calculus of variations. (orig.)
Rapid Assessment Of The Fundamental Property Variation Of Wood
Chi-Leung So; Leslie H. Groom; Timothy G. Rials; Rebecca Snell; Stephen S. Kelley; Robert Meglen
2002-01-01
Abstract - Genetic variation, site conditions, silvicultural treatments, seasonal effects, and their complex interaction are all vitally-important factors accounting for the variability and quality of the raw material produced - wood. Quality can be measured in several ways that generally influence the end use. The most desirable measure is the...
Testing for a constant coefficient of variation in nonparametric regression
Dette, Holger; Marchlewski, Mareen; Wagener, Jens
2010-01-01
In the common nonparametric regression model Y_i=m(X_i)+sigma(X_i)epsilon_i we consider the problem of testing the hypothesis that the coefficient of the scale and location function is constant. The test is based on a comparison of the observations Y_i=\\hat{sigma}(X_i) with their mean by a smoothed empirical process, where \\hat{sigma} denotes the local linear estimate of the scale function. We show weak convergence of a centered version of this process to a Gaussian process under the null ...
Romano, Antonio Enea
2014-01-01
Motivated by reported claims of the measurements of a variation of the fine structure constant $\\alpha$ we consider a theory where the electric charge, and consequently $\\alpha$, is not a constant but depends on the Ricci scalar $R$. %We then show how this can be considered a particular case of the Bekenstein theory in which there is no need to %introduce an additional kinetic term for the scalar field associated to the electric charge, since the Einstein's% %equations are sufficient to determine the geometry and, consequently the Ricci scalar. We then study the cosmological implications of this theory, considering in particular the effects of dark energy and of a cosmological constant on the evolution of $\\alpha$. Some low-red shift expressions for the variation of $\\alpha(z)$ are derived, showing the effects of the equation of state of dark energy on $\\alpha$ and observing how future measurements of the variation of the fine structure constant could be used to determine indirectly the equation of state of d...
Energy Technology Data Exchange (ETDEWEB)
Schwob, C
2006-12-15
This document reviews the theoretical and experimental achievements of the author concerning highly accurate atomic spectroscopy applied for the determination of fundamental constants. A pure optical frequency measurement of the 2S-12D 2-photon transitions in atomic hydrogen and deuterium has been performed. The experimental setting-up is described as well as the data analysis. Optimized values for the Rydberg constant and Lamb shifts have been deduced (R = 109737.31568516 (84) cm{sup -1}). An experiment devoted to the determination of the fine structure constant with an aimed relative uncertainty of 10{sup -9} began in 1999. This experiment is based on the fact that Bloch oscillations in a frequency chirped optical lattice are a powerful tool to transfer coherently many photon momenta to the atoms. We have used this method to measure accurately the ratio h/m(Rb). The measured value of the fine structure constant is {alpha}{sub -1} = 137.03599884 (91) with a relative uncertainty of 6.7*10{sup -9}. The future and perspectives of this experiment are presented. This document presented before an academic board will allow his author to manage research work and particularly to tutor thesis students. (A.C.)
Time variation of the fine structure constant α from realistic models of Oklo reactors.
Gould, C. R.; Sharapov, E. I.; Lamoreaux, S. K.
2006-11-01
The topic of whether the fundamental constants of nature vary with time has been a subject of great interest since Dirac originally proposed the possibility that GN˜1/tuniverse. Recent observations of absorption spectra lines from distant quasars appeared to indicate a possible increase in the fine structure constant α over ten billion years. Contrarily, analyses of the time evolution of α from Oklo natural nuclear reactor data have yielded inconsistent results, some indicating a decrease over two billion years while others indicated no change. We have used known Oklo reactor epithermal spectral indices as criteria for selecting realistic reactor models. Reactors RZ2 and RZ10 were modeled with MCNP and the resulting neutron spectra were used to calculate the change in the ^149Sm capture cross section as a function of a possible shift in the energy of the 97.3-meV resonance. Our study resolves the contradictory situation with previous Oklo α-results. Our suggested 2 σ bound on a possible time variation of α over two billion years is stringent: -0.11 <=δαα <=0.24, in units of 10-7, but model dependent in that it assumes only α has varied over time.
Energy Technology Data Exchange (ETDEWEB)
Inostroza, Natalia; Fortenberry, Ryan C.; Lee, Timothy J. [NASA Ames Research Center, Moffett Field, CA 94035-1000 (United States); Huang, Xinchuan, E-mail: Timothy.J.Lee@nasa.gov [SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States)
2013-12-01
Through established, highly accurate ab initio quartic force fields, a complete set of fundamental vibrational frequencies, rotational constants, and rovibrational coupling and centrifugal distortion constants have been determined for both the cyclic 1 {sup 1} A' and bent 2 {sup 1} A' DCCN, H{sup 13}CCN, HC{sup 13}CN, and HCC{sup 15}N isotopologues of HCCN. Spectroscopic constants are computed for all isotopologues using second-order vibrational perturbation theory (VPT2), and the fundamental vibrational frequencies are computed with VPT2 and vibrational configuration interaction (VCI) theory. Agreement between VPT2 and VCI results is quite good, with the fundamental vibrational frequencies of the bent isomer isotopologues in accord to within a 0.1-3.2 cm{sup –1} range. Similar accuracies are present for the cyclic isomer isotopologues. The data generated here serve as a reference for astronomical observations of these closed-shell, highly dipolar molecules using new, high-resolution telescopes and as reference for laboratory studies where isotopic labeling may lead to elucidation of the formation mechanism for the known interstellar molecule: X {sup 3} A' HCCN.
Mavromatos, Nick E.
2016-11-01
On the occasion of a century from the proposal of General relativity by Einstein, I attempt to tackle some open issues in modern cosmology, via a toy but non-trivial model. Specifically, I would like to link together: (i) the smallness of the cosmological constant today, (ii) the evolution of the universe from an inflationary era after the bigbang till now, and (iii) local supersymmetry in the gravitational sector (supergravity) with a broken spectrum at early eras, by making use of the concept of the "running vacuum" in the context of a simple toy model of four-dimensional N = 1 supergravity. The model is characterised by dynamically broken local supersymmetry, induced by the formation of gravitino condensates in the early universe. As I will argue, there is a Starobinsky-type inflationary era characterising the broken supersymmetry phase in this model, which is compatible with the current cosmological data, provided a given constraint is satisfied among some tree-level parameters of the model and the renormalised cosmological constant of the de Sitter background used in the analysis. Applying the "running vacuum" concept, then, to the effective field theory at the exit of inflation, makes a smooth connection (in cosmic time) with the radiation dominance epoch and subsequently with the current era of the Universe, characterised by a small (but dominant) cosmological-constant contribution to the cosmic energy density. In this approach, the smallness of the cosmological constant today is attributed to the failure (due to quantum gravity non-perturbative effects) of the aforementioned constraint.
Do the Fundamental Constants Vary in the Course of the Cosmological Evolution?
Ivanchik, A V; Petitjean, P; Varshalovich, D A
2002-01-01
We estimate the cosmological variation of the proton-to-electron mass ratio \\mu=m_p/m_e by measuring the wavelengths of molecular hydrogen transitions in the early universe. The analysis is performed using high spectral resolution observations (FWHM ~ 7 km/s) of two damped Lyman-\\alpha systems at z_{abs}=2.3377 and 3.0249 observed along the lines of sight to the quasars Q 1232+082 and Q 0347-382 respectively. The most conservative result of the analysis is a possible variation of \\mu over the last ~ 10 Gyrs, with an amplitude \\Delat\\mu/\\mu = (5.7+-3.8)x10^{-5}. The result is significant at the 1.5\\sigma level only and should be confirmed by further observations. This is the most stringent estimate of a possible cosmological variation of \\mu obtained up to now.
Nuclear Data in Oklo and Time-Variability of Fundamental Coupling Constants
Fujii, Y; Fukahori, T; Ohnuki, T; Nakagawa, M; Hidaka, H; Oura, Y; Møller, P; Fujii, Yasunori; Iwamoto, Akira; Fukahori, Tokio; Ohnuki, Toshihiko; Nakagawa, Masayuki; Hidaka, Hiroshi; Oura, Yasuji; Moller, Peter
2001-01-01
We re-examined Shlyakhter's analysis of the Sm data in Oklo. With a special care of minimizing contamination due to the inflow of the isotope after the end of the reactor activity, we confirmed that his result on the time-variability of the fine-structure constant, $|\\dot{\\alpha}/\\alpha |\\lsim 10^{-17}{\\rm y}^{-1}$, was basically correct. In addition to this upper bound, however, we obtained another result that indicates a different value of $\\alpha$ 2 billion years ago. We add comments on the recent result from QSO's.
Investigation of the Fundamental Constants Stability Based on the Reactor Oklo Burn-Up Analysis
Onegin, M. S.; Yudkevich, M. S.; Gomin, E. A.
2012-12-01
The burn-up of few samples of the natural Oklo reactor zones 3, 5 was calculated using the modern Monte Carlo code. We reconstructed the neutron spectrum in the core by means of the isotope ratios: 147Sm/148Sm and 176Lu/175Lu. These ratios unambiguously determine the water content and core temperature. The isotope ratio of the 149Sm in the sample calculated using this spectrum was compared with experimental one. The disagreement between these two values allows one to limit a possible shift of the low lying resonance of 149Sm. Then, these limits were converted to the limits for the change of the fine structure constant α. We have found out, that for the rate of α change, the inequality ěrt˙ {α }/α ěrt<= 5× 10-18 is fulfilled, which is one order higher than our previous limit.
Investigation of the fundamental constants stability based on the reactor Oklo burn-up analysis
Onegin, M S
2010-01-01
The burn-up for SC56-1472 sample of the natural Oklo reactor zone 3 was calculated using the modern Monte Carlo codes. We reconstructed the neutron spectrum in the core by means of the isotope ratios: $^{147}$Sm/$^{148}$Sm and $^{176}$Lu/$^{175}$Lu. These ratios unambiguously determine the spectrum index and core temperature. The effective neutron absorption cross section of $^{149}$Sm calculated using this spectrum was compared with experimental one. The disagreement between these two values allows to limit a possible shift of the low laying resonance of $^{149}$Sm even more . Then, these limits were converted to the limits for the change of the fine structure constant $\\alpha$. We found that for the rate of $\\alpha$ change the inequality $|\\delta \\dot{\\alpha}/\\alpha| \\le 5\\cdot 10^{-18}$ is fulfilled, which is of the next higher order than our previous limit.
Probing QED and fundamental constants through laser spectroscopy of vibrational transitions in HD+
Biesheuvel, J; Hilico, L; Eikema, K S E; Ubachs, W; Koelemeij, J C J
2016-01-01
The simplest molecules in nature, molecular hydrogen ions in the form of H2+ and HD+, provide an important benchmark system for tests of quantum electrodynamics in complex forms of matter. Here, we report on such a test based on a frequency measurement of a vibrational overtone transition in HD+ by laser spectroscopy. We find that the theoretical and experimental frequencies are equal to within 0.6(1.1) parts per billion, which represents the most stringent test of molecular theory so far. Our measurement not only confirms the validity of high-order quantum electrodynamics in molecules, but also enables the long predicted determination of the proton-to-electron mass ratio from a molecular system, as well as improved constraints on hypothetical fifth forces and compactified higher dimensions at the molecular scale. With the perspective of comparisons between theory and experiment at the 0.01 part-per-billion level, our work demonstrates the potential of molecular hydrogen ions as a probe of fundamental physica...
Mavromatos, Nick E
2016-01-01
On the occasion of a century from the proposal of General relativity by Einstein, I attempt to tackle some open issues in modern cosmology, via a toy but non-trivial model. Specifically, I would like to link together: (i) the smallness of the cosmological constant today, (ii) the evolution of the universe from an inflationary era after the big-bang till now, and (iii) local supersymmetry in the gravitational sector (supergravity) with a broken spectrum at early eras, by making use of the concept of the "running vacuum" in the context of a simple toy model of four-dimensional N=1 supergravity. The model is characterised by dynamically broken local supersymmetry, induced by the formation of gravitino condensates in the early universe. As I will argue, there is a Starobinsky-type inflationary era characterising the broken supersymmetry phase in this model, which is compatible with the current cosmological data, provided a given constraint is satisfied among some tree-level parameters of the model and the renorma...
Du, Lin; Mackeprang, Kasper; Kjaergaard, Henrik G
2013-07-07
We have measured gas phase vibrational spectra of the bimolecular complex formed between methanol (MeOH) and dimethylamine (DMA) up to about 9800 cm(-1). In addition to the strong fundamental OH-stretching transition we have also detected the weak second overtone NH-stretching transition. The spectra of the complex are obtained by spectral subtraction of the monomer spectra from spectra recorded for the mixture. For comparison, we also measured the fundamental OH-stretching transition in the bimolecular complex between MeOH and trimethylamine (TMA). The enthalpies of hydrogen bond formation (ΔH) for the MeOH-DMA and MeOH-TMA complexes have been determined by measurements of the fundamental OH-stretching transition in the temperature range from 298 to 358 K. The enthalpy of formation is found to be -35.8 ± 3.9 and -38.2 ± 3.3 kJ mol(-1) for MeOH-DMA and MeOH-TMA, respectively, in the 298 to 358 K region. The equilibrium constant (Kp) for the formation of the MeOH-DMA complex has been determined from the measured and calculated transition intensities of the OH-stretching fundamental transition and the NH-stretching second overtone transition. The transition intensities were calculated using an anharmonic oscillator local mode model with dipole moment and potential energy curves calculated using explicitly correlated coupled cluster methods. The equilibrium constant for formation of the MeOH-DMA complex was determined to be 0.2 ± 0.1 atm(-1), corresponding to a ΔG value of about 4.0 kJ mol(-1).
The New SI and the CODATA recommended values of the fundamental constants 2014 (arXiv:1507.07956)
Pavese, Franco
2015-01-01
This note's aim is to point out some standing features of the present CODATA method in the light of the recent CODATA table of the 2014 recommended values for the fundamental constants published on paper arXiv:1507.07956. A comprehensive discussion on this and related issues is becoming very important in view of the foreseen revision of the SI, presently planned for 2018. These features may raise doubts on a possible mixing of physical reasons of general validity in science with some needs specific of metrology concerning the base units of the International System (SI) of measurement units.
Institute of Scientific and Technical Information of China (English)
COHN William S.; LU Guo Zhen
2002-01-01
We derive the explicit fundamental solutions for a class of degenerate (or singular) oneparameter subelliptic differential operators on groups of Heisenberg (H) type. This extends the result of Kaplan for the sub-Laplacian on H-type groups, which in turn generalizes Folland's result on the Heisenberg group. As an application, we obtain a one-parameter representation formula for Sobolev functions of compact support on H-type groups. By choosing the parameter equal to the homogeneous dimension Q and using the Moser-Trudinger inequality for the convolutional type operator on stratified groups obtained in [18], we get the following theorem which gives the best constant for the MoserTrudinger inequality for Sobolev functions on H-type groups.Let G be any group of Heisenberg type whose Lie algebra is generated by m left invariant vectorfields and with a q-dimensional center. Let Q = m + 2q, Q′= Q/Q-1 andAQ= [(1/4)q-1/2πq+m/2Γ(Q+m/4)/ QΓ(m/2)Γ(Q/2)] 1/Q-1Then,F∈sup C∞U(Ω) { 1/|Ω|∫Ωexp (AQ(F(u)/‖ GF‖Q)Q′)du}＜∞,with AQ as the sharp constant, where G denotes the subelliptic gradient on G.This continues the research originated in our earlier study of the best constants in Moser-Teudinger inequalities and fundamental solutions for one-parameter subelliptic operators on the Heisenberg group[18].
An upper limit to the secular variation of the gravitational constant from white dwarf stars
García-Berro, Enrique; Torres, Santiago; Althaus, Leandro G; Isern, Jordi
2011-01-01
A variation of the gravitational constant over cosmological ages modifies the main sequence lifetimes and white dwarf cooling ages. Using an state-of-the-art stellar evolutionary code we compute the effects of a secularly varying G on the main sequence ages and, employing white dwarf cooling ages computed taking into account the effects of a running G, we place constraints on the rate of variation of Newton's constant. This is done using the white dwarf luminosity function and the distance of the well studied open Galactic cluster NGC 6791. We derive an upper bound G'/G ~ -1.8 10^{-12} 1/yr. This upper limit for the secular variation of the gravitational constant compares favorably with those obtained using other stellar evolutionary properties, and can be easily improved if deep images of the cluster allow to obtain an improved white dwarf luminosity function.
Time variation of the fine structure constant in the early universe and the Bekenstein model
Mosquera, Mercedes E; Landau, Susana J; Vucetich, Hector
2007-01-01
We use observational primordial abundances of $\\De$, $\\Het$, $\\He$ and $\\Li$, recent data from the Cosmic Microwave Background and the 2dFGRS power spectrum, to put limits on the variation of the fine structure constant in the early universe. Furthermore, we use these constraints together with other astronomical and geophysical bounds from the late universe to test Bekenstein's model for the variation of $\\alpha$. The model is not able to fit all observational and experimental data.
Directory of Open Access Journals (Sweden)
Mohammad Reza Keyhani
2012-03-01
Full Text Available Background and Aim: Voice disorders assess with the help of laboratory equipments and perceptual evaluation. Voice samples involve vowel prolongation, text-reading or conversational speech. In Iran, Rainbow text and Grandfather text, were developed for assessing voice.Methods: This study was cross-sectional and descriptive-analytical. Mean and fundamental frequency variations range in 120 normal males and females aging from 20-59 years old were studied. Voice samples of reading both texts were gathered and compared.Results: Mean fundamental frequency in males in Grandfather text was 137.93 with SD 1.2 and in Rainbow text was 135.09 with SD 1.1 (p>0.05, in females Grandfather and Rainbow texts were 206.07 with SD 0.9 and 204.23 with SD 2.1, respectively (p>0.05. Fundamental frequency variations range in Grandfather text in males was 88.10 with SD 0.8 and in females was 116.77 with SD 1.3 and in Rainbow text in males was 90.92 with SD 1.1, in females was 116.08 with SD 1.2 (p>0.05. Mean fundamental frequency of males in each text didn't show significant difference in age groups and just in 50-59 age group of the female population showed significant difference. Fundamental frequency variations range didn't show significant difference in males and females in both texts.Conclusion: These two texts were the same in measurement of average and fundamental frequency variations range in adults. Significant difference showed between 50-59 age group of the female population and other groups.
Stadnik, Y V
2015-01-01
We present an overview of recent developments in the detection of light bosonic dark matter, including axion, pseudoscalar axion-like and scalar dark matter, which form either a coherently oscillating classical field or topological defects (solitons). We emphasise new high-precision laboratory and astrophysical measurements, in which the sought effects are linear in the underlying interaction strength between dark matter and ordinary matter, in contrast to traditional detection schemes for dark matter, where the effects are quadratic or higher order in the underlying interaction parameters and are extremely small. New terrestrial experiments include measurements with atomic clocks, spectroscopy, atomic and solid-state magnetometry, torsion pendula, ultracold neutrons, and laser interferometry. New astrophysical observations include pulsar timing, cosmic radiation lensing, Big Bang nucleosynthesis and cosmic microwave background measurements. We also discuss various recently proposed mechanisms for the inducti...
DEFF Research Database (Denmark)
Ghotbi, Abdoul R; Barari, Amin
2009-01-01
Due to wide range of interest in use of bio-economic models to gain insight in to the scientific management of renewable resources like fisheries and forestry, variational iteration method (VIM) is employed to approximate the solution of the ratio-dependent predator-prey system with constant effort...
Institute of Scientific and Technical Information of China (English)
王艳; 钱英; 冯文林; 刘若庄
2003-01-01
An implementation of the variational quantum RRKM program is presented to utilize the direct ab initio dynamics approach for calculating k(E, J), k(E) and k(T) within the framework of the microcanonical transition state (μTST) and microcanonical variational TST (μVT) theories. An algorithm including tunneling contributions in Beyer-Swinehart method for calculating microcanonical rate constants is also proposed. An efficient piece-wise interpolation method is developed to evaluate the Boltzmann integral in calculation of thermal rate constants. Calculations on several test reactions, namely the H(D)2CO→H(D)2 + CO, CH2CO→CH2 + CO and CH4 + H→CH3 + H2 reactions, show that the results are in good agreement with the previous rate constants calculations. This approach would require much less computational resource.
Constraints on field theoretical models for variation of the fine structure constant
Steinhardt, Charles L.
2005-02-01
Recent theoretical ideas and observational claims suggest that the fine structure constant α may be variable. We examine a spectrum of models in which α is a function of a scalar field. Specifically, we consider three scenarios: oscillating α, monotonic time variation of α, and time-independent α that is spatially varying. We examine the constraints imposed upon these theories by cosmological observations, particle detector experiments, and “fifth force” experiments. These constraints are very strong on models involving oscillation but cannot compete with bounds from the Oklo subnuclear reactor on models with monotonic timelike variation of α. One particular model with spatial variation is consistent with all current experimental and observational measurements, including those from two seemingly conflicting measurements of the fine structure constant using the many multiplet method on absorption lines.
Bekenstein model and the time variation of the strong coupling constant
Chamoun, N; Vucetich, H
2001-01-01
We propose to generalize Bekenstein model for the time variation of the fine structure "constant" $\\alpha_{em}$ to QCD strong coupling constant $\\alpha_S$. We find that, except for a ``fine tuned'' choice of the free parameters, the extension can not be performed trivially without being in conflict with experimental constraints and this rules out $\\alpha_S$ variability. This is due largely to the huge numerical value of the QCD vacuum gluon condensate when compared to the mass density of the universe.
Bambi, Cosimo
2013-01-01
Extensions of general relativity and theories aiming at unifying gravity with the forces of the Standard Model are usually characterized by new degrees of freedom and violations of the Einstein Equivalence Principle. The search for time and/or space variations of fundamental parameters like the fine structure constant $\\alpha$ tests the assumption of Local Position Invariance. In this letter, I show that the analysis of the K$\\alpha$ iron line observed in the X-ray spectrum of black holes can probe $\\alpha$ in gravitational potentials relative to Earth of $\\Delta \\phi \\approx 0.1$. From the measurements of the black hole in Cygnus X-1 reported in the literature, one obtains $|\\Delta \\alpha / \\alpha| \\lesssim 0.01$.
The variation of the fine structure constant: an update of statistical analysis with recent data
Kraiselburd, Lucila; Simeone, Claudio
2013-01-01
We analyze different astronomical data of the variation in the fine structure constant obtained with KECK and VLT to check their consistency. We test consistency using the Student test and confidence intervals. We split the data sets in smaller intervals and group them by i) redshift and ii) angular position. Another statistical analysis is proposed considering phenomenological models for the variation in \\alpha\\ . Results show consistency for reduced intervals for each pair of data sets considered and suggest that the variation in \\alpha\\ is important at higher redshifts.Even though the "dipole model" proposed by Webb et al. seems to be the most accurate phenomenological model, the statistical analyses indicates that the variation in \\alpha\\ might be depending both on redshift and angular position.
Variation of the fine-structure constant from the de Sitter invariant special relativity
Institute of Scientific and Technical Information of China (English)
CHEN Shao-Xia; XIAO Neng-Chao; YAN Mu-Lin
2008-01-01
We discuss the variation of the fine-structure constant,α.There are obvious discrepancies among the results of α-variation from recent Quasi-stellar observation experiments and from the Oklo uranium mine analysis.We use dS Sitter invariant Special Relativity (SRc,R) and Dirac large number hypothesis to discuss this puzzle,and present a possible solution to the disagreement.By means of the observational data and the discussions presented in this paper,we estimate the radius of the Universe in SRc,R which is about ～2(√5)×1011l.y.
Constraining spatial variations of the fine-structure constant in symmetron models
Pinho, A. M. M.; Martinelli, M.; Martins, C. J. A. P.
2017-06-01
We introduce a methodology to test models with spatial variations of the fine-structure constant α, based on the calculation of the angular power spectrum of these measurements. This methodology enables comparisons of observations and theoretical models through their predictions on the statistics of the α variation. Here we apply it to the case of symmetron models. We find no indications of deviations from the standard behavior, with current data providing an upper limit to the strength of the symmetron coupling to gravity (log β2 constrain the model when also the symmetry breaking scale factor aSSB is free to vary.
Reconstructing the evolution of dark energy with variations of fundamental parameters
Nunes, N J; Martins, C J A P; Robbers, G
2009-01-01
Under the assumption that the variations of parameters of nature and the current acceleration of the universe are related and governed by the evolution of a single scalar field, we show how information can be obtained on the nature of dark energy from observational detection of (or constraints on) cosmological variations of the fine structure constant and the proton-to-electron mass ratio. We also comment on the current observational status, and on the prospects for improvements with future spectrographs such as ESPRESSO and CODEX.
New Constraints on Spatial Variations of the Fine Structure Constant from Clusters of Galaxies
Directory of Open Access Journals (Sweden)
Ivan De Martino
2016-12-01
Full Text Available We have constrained the spatial variation of the fine structure constant using multi-frequency measurements of the thermal Sunyaev-Zeldovich effect of 618 X-ray selected clusters. Although our results are not competitive with the ones from quasar absorption lines, we improved by a factor 10 and ∼2.5 previous results from Cosmic Microwave Background power spectrum and from galaxy clusters, respectively.
Cosmological implications in electrodynamics due to variations of the fine structure constant
Martínez-Ledesma, J L
2002-01-01
Astronomical observations are strongly suggesting that the fine structure constant varies cosmologically. We present an analysis on the consequences that this variations might induce on the electromagnetic field as a whole. We show that under this circumstances the electrodynamics in vacuum of the universe are described by two fields, the ``standard'' Maxwell's field and a new scalar field. We provide a generalized Lorentz force which can be used to test our results experimentally.
Strong limit on the spatial and temporal variations of the fine-structure constant
Le, T. D.
2016-10-01
Observed spectra of quasars provide a powerful tool to test the possible spatial and temporal variations of the fine-structure constant α = e 2/ћc over the history of the Universe. It is demonstrated that high sensitivity to the variation of α can be obtained from a comparison of the spectra of quasars and laboratories. We reported a new constraint on the variation of the fine-structure constant based on the analysis of the optical spectra of the fine-structure transitions in [NeIII], [NeV], [OIII], [OI] and [SII] multiplets from 14 Seyfert 1.5 galaxies. The weighted mean value of the α-variation derived from our analysis over the redshift range 0.035 < z < 0.281 Δα/α= (4.50 +/- 5.53) \\times 10-5. This result presents strong limit improvements on the constraint on Δα/α compared to the published in the literature
Constraints on a possible variation of the fine structure constant from galaxy cluster data
Holanda, R F L; Alcaniz, J S; G., I E Sanchez; Busti, V C
2015-01-01
We propose a new method to probe a possible time evolution of the fine structure constant $\\alpha$ from X-ray and Sunyaev-Zeldovich measurements of the gas mass fraction ($f_{gas}$) in galaxy clusters. Taking into account a direct relation between variations of $\\alpha$ and violations of the distance-duality relation, we discuss constraints on $\\alpha$ for a class of dilaton runaway models. Although not yet competitive with bounds from high-$z$ quasar absorption systems, our constraints, considering a sample of 29 measurements of $f_{gas}$, in the redshift interval $0.14 < z < 0.89$, provide an independent estimate of $\\alpha$ variation at low and intermediate redshifts. Furthermore, current and planned surveys will provide a larger amount of data and thus allow to improve the limits on $\\alpha$ variation obtained in the present analysis.
Accounting Fundamentals and the Variation of Stock Price: Factoring in the Investment Scalability
Directory of Open Access Journals (Sweden)
Sumiyana Sumiyana
2010-05-01
Full Text Available This study develops a new return model with respect to accounting fundamentals. The new return model is based on Chen and Zhang (2007. This study takes into account theinvestment scalability information. Specifically, this study splitsthe scale of firm’s operations into short-run and long-runinvestment scalabilities. We document that five accounting fun-damentals explain the variation of annual stock return. Thefactors, comprised book value, earnings yield, short-run andlong-run investment scalabilities, and growth opportunities, co associate positively with stock price. The remaining factor,which is the pure interest rate, is negatively related to annualstock return. This study finds that inducing short-run and long-run investment scalabilities into the model could improve the degree of association. In other words, they have value rel-evance. Finally, this study suggests that basic trading strategieswill improve if investors revert to the accounting fundamentals. Keywords: accounting fundamentals; book value; earnings yield; growth opportunities; shortrun and longrun investment scalabilities; trading strategy;value relevance
High pressure phase transition and variation of elastic constants of diluted magnetic semiconductors
Energy Technology Data Exchange (ETDEWEB)
Varshney, Dinesh; Sharma, P.; Kaurav, N. [School of Physics, Vigyan Bhawan, Devi Ahilya University, Takshila Campus, Indore 452017 (India); Shah, S. [Department of Physics, P. M. B. Gujarati Science College, Indore-452001 (India); Singh, R.K. [M. P. Bhoj (Open) University, Shivaji Nagar, Bhopal-462016 (India)
2004-11-01
A theoretical study of the high-pressure phase transition and elastic behavior in diluted magnetic semiconductors Zn{sub 0.83}Mn{sub 0.17}Se, using a three-body interaction (TBI) potential caused by the electron-shell deformation of the overlapping ions is carried out. The estimated values of phase transition pressure and the vast volume discontinuity in pressure-volume (PV) phase diagram indicate the structural phase transition from zincblende (B3) to rock salt (B1). The variation of second-order elastic constants with pressure resembles that observed in some binary semiconductors. The inconsistency in the deduced value of pressure derivative of second order elastic constant with the available data is attributed to the fact that we derive expressions neglecting thermal effects and assuming the overlap repulsion significant only up to nearest neighbors. The vdW interaction is effective in obtaining the thermodynamical parameters such as Debye temperature, Gruneisen parameter, thermal expansion coefficient, compressibility as well phase stability in diluted magnetic semiconductors. It is revealed that TBI model has a promise to predict the phase transition pressure and the pressure variation of elastic constants of other semiconductors as well. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
The variation of the fine-structure constant from disformal couplings
van de Bruck, Carsten; Mifsud, Jurgen; Nunes, Nelson J.
2015-12-01
We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, α. As a result, the theory we consider can explain the non-zero reported variation in the evolution of α by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with the current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of α. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical results, we find that the introduction of a non-minimal electromagnetic coupling enhances the cosmological variation in α. Better constrained data is expected to be reported by ALMA and with the forthcoming generation of high-resolution ultra-stable spectrographs such as PEPSI, ESPRESSO, and ELT-HIRES. Furthermore, an expected increase in the sensitivity of molecular and nuclear clocks will put a more stringent constraint on the theory.
Berengut, J C; Dzuba, V A; Flambaum, V V
2010-09-17
We study atomic systems that are in the frequency range of optical atomic clocks and have enhanced sensitivity to potential time variation of the fine-structure constant α. The high sensitivity is due to coherent contributions from three factors: high nuclear charge Z, high ionization degree, and significant differences in the configuration composition of the states involved. Configuration crossing keeps the frequencies in the optical range despite the large ionization energies. We discuss a few promising examples that have the largest α sensitivities seen in atomic systems.
Time Variation of the Fine Structure Constant in the Spacetime of a Cosmic Domain Wall
Campanelli, L.; Cea, P.; Tedesco, L.
The gravitational field produced by a domain wall acts as a medium with spacetime-dependent permittivity ɛ. Therefore, the fine structure constant α=e2/4πɛ will be a time-dependent function at fixed position. The most stringent constraint on the time-variation of α comes from the natural reactor Oklo and gives |˙ α /α | < few × 10-17 yr-1. This limit constrains the tension of a cosmic domain wall to be less than σ ≲ 10-2 MeV3, and then represents the most severe limit on the energy density of a cosmic wall stretching our Universe.
Time Variation of the Fine Structure Constant in the Spacetime of a Domain Wall
Campanelli, L; Tedesco, L
2005-01-01
The gravitational field produced by a domain wall acts as a medium with spacetime-dependent permittivity \\epsilon. Therefore, the fine structure constant \\alpha = e^2/4 \\pi \\epsilon will be a time-dependent function at fixed position. The most stringent constraint on the time-variation of \\alpha comes from the natural reactor Oklo and gives |\\dot{\\alpha}/\\alpha| < few 10^{-17} yr^{-1}. This limit constrains the tension of a cosmic domain wall to be less than \\sigma \\lesssim 10^{-2} MeV^3, and then represents the most severe limit on the energy density of a cosmic wall stretching our Universe.
Feature analysis of the scale factor variation on a constant rate biased ring laser gyro
Institute of Scientific and Technical Information of China (English)
Shiqiao Qin; Zongsheng Huang; Xingshu Wang
2007-01-01
Scale factor of a constant rate biased ring laser gyro (RLG) is studied both theoretically and experimentally.By analyzing experimental data, we find that there are three main terms contributing to the scale factor deviation. One of them is independent of time, the second varies linearly with time and the third varies exponentially with time. Theoretical analyses show that the first term is caused by experimental setup,the second and the third are caused by un-uniform thermal expension and cavity loss variation of the RLG.
Variation of the fine-structure constant from the de Sitter invariant special relativity
Chen, Shao-Xia; Xiao, Neng-Chao; Yan, Mu-Lin
2008-08-01
We discuss the variation of the fine-structure constant, α. There are obvious discrepancies among the results of α-variation from recent Quasi-stellar observation experiments and from the Oklo uranium mine analysis. We use dS Sitter invariant Special Relativity (Script SScript Rc,R) and Dirac large number hypothesis to discuss this puzzle, and present a possible solution to the disagreement. By means of the observational data and the discussions presented in this paper, we estimate the radius of the Universe in Script SScript Rc,R which is about ~2√5×1011l.y. Supported by National Natural Science Foundation of China (90403021) and PhD Program Funds of Education Ministry of China (20020358040)
Constraints on a possible variation of the fine structure constant from galaxy cluster data
Holanda, R. F. L.; Landau, S. J.; Alcaniz, J. S.; Sánchez G., I. E.; Busti, V. C.
2016-05-01
We propose a new method to probe a possible time evolution of the fine structure constant α from X-ray and Sunyaev-Zel'dovich measurements of the gas mass fraction (fgas) in galaxy clusters. Taking into account a direct relation between variations of α and violations of the distance-duality relation, we discuss constraints on α for a class of dilaton runaway models. Although not yet competitive with bounds from high-z quasar absorption systems, our constraints, considering a sample of 29 measurements of fgas, in the redshift interval 0.14 intermediate redshifts. Furthermore, current and planned surveys will provide a larger amount of data and thus allow to improve the limits on α variation obtained in the present analysis.
Energy Technology Data Exchange (ETDEWEB)
Chamoun, N [Departamento de Fisica, Universidad Nacional de La Plata, cc67, 1900 La Plata (Argentina); Landau, S J [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque, cp 1900 La Plata (Argentina); Mosquera, M E [Facultad de Ciencias Astronomicas y GeofIsicas, Universidad Nacional de La Plata, Paseo del Bosque, cp 1900 La Plata (Argentina); Vucetich, Hector [Departamento de Fisica, Universidad Nacional de La Plata, cc67, 1900 La Plata (Argentina)
2007-02-15
We use the semi-analytic method of Esmailzadeh et al (1991 Astrophys. J. 378 504-18) to calculate the abundances of helium and deuterium produced during Big Bang nucleosynthesis assuming the fine structure constant and the Higgs vacuum expectation value may vary in time. We analyse the dependence on the fundamental constants of the nucleon mass, nuclear binding energies and cross sections involved in the calculation of the abundances. Unlike previous works, we do not assume the chiral limit of QCD. Rather, we take into account the quark masses and consider the one-pion exchange potential, within perturbation theory, for the proton-neutron scattering. However, we do not consider the time variation of the strong interactions scale but attribute the changes in the quark masses to the temporal variation of the Higgs vacuum expectation value. Using the observational data of the helium and deuterium, we put constraints on the variation of the fundamental constants between the time of nucleosynthesis and the present time.
The variation of the fine-structure constant from disformal couplings
van de Bruck, Carsten; Nunes, Nelson J
2015-01-01
We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure constant, alpha. As a result, the theory we consider can explain the non-zero reported variation in the evolution of alpha by purely considering disformal couplings. We also find that if matter and photons are coupled in the same way to the scalar field, disformal couplings itself do not lead to a variation of the fine-structure constant. A number of scenarios are discussed consistent with the current astrophysical, geochemical, laboratory and the cosmic microwave background radiation constraints on the cosmological evolution of alpha. The models presented are also consistent with the current type Ia supernovae constraints on the effective dark energy equation of state. We find that the Oklo bound in particular puts strong constraints on the model parameters. From our numerical r...
Gardner, Carl L.
2003-08-01
Cosmological variation of the fine structure constant α due to the evolution of a spatially homogeneous ultralight scalar field (m˜H0) during the matter and Λ dominated eras is analyzed. Agreement of Δα/α with the value suggested by recent observations of quasar absorption lines is obtained by adjusting a single parameter, the coupling of the scalar field to matter. Asymptotically α(t) in this model goes to a constant value α¯≈α0 in the early radiation and the late Λ dominated eras. The coupling of the scalar field to (nonrelativistic) matter drives α slightly away from α¯ in the epochs when the density of matter is important. Simultaneous agreement with the more restrictive bounds on the variation |Δα/α| from the Oklo natural fission reactor and from meteorite samples can be achieved if the mass of the scalar field is on the order of 0.5 0.6 HΛ, where HΛ=Ω1/2ΛH0. Depending on the scalar field mass, α may be slightly smaller or larger than α0 at the times of big bang nucleosynthesis, the emission of the cosmic microwave background, the formation of early solar system meteorites, and the Oklo reactor. The effects on the evolution of α due to nonzero mass for the scalar field are emphasized. An order of magnitude improvement in the laboratory technique could lead to a detection of (α˙/α)0.
Chuang, Yao-Yuan
2007-08-01
Variational transition state theory with multidimensional tunneling (VTST/MT) has been used for calculating the rate constants of reactions. The updated Hessians have been used to reduce the computational costs for both geometry optimization and trajectory following procedures. In this paper, updated Hessians are used to reduce the computational costs while calculating the rate constants applying VTST/MT. Although we found that directly applying the updated Hessians will not generate good vibrational frequencies along the minimum energy path (MEP), however, we can either re-compute the full Hessian matrices at fixed intervals or calculate the Block Hessians, which is constructed by numerical one-side difference for the Hessian elements in the "critical" region and Bofill updating scheme for the rest of the Hessian elements. Due to the numerical instability of the Bofill update method near the saddle point region, we have suggested a simple strategy in which we follow the MEP until certain percentage of the classical barrier height from the barrier top with full Hessians computed and then performing rate constant calculation with the extended MEP using Block Hessians. This strategy results a mean unsigned percentage deviation (MUPD) around 10% with full Hessians computed till the point with 80% classical barrier height for four studied reactions. This proposed strategy is attractive not only it can be implemented as an automatic procedure but also speeds up the VTST/MT calculation via embarrassingly parallelization to a personal computer cluster.
Precision Measurements: Testing the Time Variation of the Fine Structure Constant
Lamoreaux, Steve
2004-05-01
Often, precision measurements from diverse fields can be used to learn new facts about the universe. The usual definition of "precision" is based on improvements over previous measurements. A review of the present state of knowledge regarding the possible time variation of the fine structure constant α will be presented; "precise" data from natural phenomena, which include an apparent shift in the red-shift-scaled fine structure in the absorption spectra of quasar light, and the isotopic abundances in the fission products of a prehistoric natural reactor in Oklo, Gabon. Prospects to improve the accuracy for the constancy of α with laboratory experiments will be discussed. Our two experimental investigations currently being developed are based on optical spectroscopy of trapped ions and on radiofrequency spectroscopy of an atomic dysprosium beam. A sensitivity of dotα/α≈ 10-18/yr is anticipated. Because this accuracy exceeds that by which the second is defined, these measurements will necessarily be differential.
Cyanobacteria Maintain Constant Protein Concentration despite Genome Copy-Number Variation.
Zheng, Xiao-Yu; O'Shea, Erin K
2017-04-18
The cyanobacterium Synechococcus elongatus PCC 7942 has multiple copies of its single chromosome, and the copy number varies in individual cells, providing an ideal system to study the effect of genome copy-number variation on cell size and gene expression. Using single-cell fluorescence imaging, we found that protein concentration remained constant across individual cells regardless of genome copy number. Cell volume and the total protein amount from a single gene were both positively, linearly correlated with genome copy number, suggesting that changes in cell volume play an important role in buffering genome copy-number variance. This study provides a quantitative examination of gene expression regulation in cells with variable genome copies and sheds light on the compensation mechanisms for variance in genome copy number. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.
Constraints on the time variation of the fine structure constant by the 5-year WMAP data
Nakashima, Masahiro; Yokoyama, Jun'ichi
2008-01-01
The constraints on the time variation of the fine structure constant at recombination epoch relative to its present value, $\\Delta\\alpha/\\alpha \\equiv (\\alpha_{\\mathrm{rec}} - \\alpha_{\\mathrm{now}})/\\alpha_{\\mathrm{now}}$, are obtained from the analysis of the 5-year WMAP cosmic microwave background data. As a result of Markov-Chain Monte-Carlo analysis, it is found that, contrary to the analysis based on the previous WMAP data, the mean value of $\\Delta\\alpha/\\alpha=-0.0009$ does not change significantly whether we use the Hubble Space Telescope (HST) measurement of the Hubble parameter as a prior or not. The resultant 95% confidence ranges of $\\Delta\\alpha/\\alpha$ are $-0.028 < \\Delta\\alpha/\\alpha < 0.026$ with HST prior and $-0.050 < \\Delta\\alpha/\\alpha < 0.042$ without HST prior.
Institute of Scientific and Technical Information of China (English)
Tianhu Hao
2005-01-01
This paper presents an exact solution of the crack tip field in functionally gradient material with exponential variation of elastic constants. The dimensionless Poisson's ratios v0 of the engineering materials (iron, glass... ) are far less than one; therefore, neglecting them, one can simplify the basic equation and the exact solution is easy to obtain.Although the exact solution for the case v0 ≠ 0 is also obtained, it is very complicated and the main result is the same with the case v0 = 0 (it will be dealt with in Appendix Ⅶ).It has been found that the exponential term exp(ax + by) in the constitutive equations becomes exp (ax/2 + by/2 - kr / 2 ) in the exact solution.
2011-01-01
of an observer located on the rotating geoid . It is specified in IAU 2000 Resolution B1.9 as a defining constant. The value for LG is taken from...compatible, TT-compatible, and TDB-compatible values are provided. Potential of the geoid , W0 The potential of the geoid , W0, is taken from the
de Martino, I; Ebeling, H; Kocevski, D
2016-01-01
We propose an improved methodology to constrain spatial variations of the fine structure constant using clusters of galaxies. We use the {\\it Planck} 2013 data to measure the thermal Sunyaev-Zeldovich effect at the location of 618 X-ray selected clusters. We then use a Monte Carlo Markov Chain algorithm to obtain the temperature of the Cosmic Microwave Background at the location of each galaxy cluster. When fitting three different phenomenological parameterizations allowing for monopole and dipole amplitudes in the value of the fine structure constant we improve the results of earlier analysis involving clusters and CMB power spectrum, and we also found that the best-fit direction of a hypothetical dipole is compatible with the direction of other known anomalies. Although the constraining power of our current datasets do not allow us to test the indications of a dipole obtained though high-resolution optical/UV spectroscopy, our results do highlight that clusters of galaxies will be a very powerful tool to pr...
Atanasov, Atanas Todorov
2016-12-01
Here is developed the hypothesis that the cell parameters of unicellular organisms (Prokaryotes and Eukaryotes) are determined by the gravitational constant (G, N.m2 /kg2), Planck constant (h, J.s) and growth rate of cells. By scaling analyses it was shown that the growth rate vgr(m/s) of unicellular bacteria and protozoa is relatively constant parameter, ranging in a narrow window of 10-12 - 10-10 m/s, in comparison to the diapason of cell mass, ranging 10 orders of magnitudes from 10-17 kg in bacteria to 10-7 kg in amoebas. By dimensional analyses it was shown that the combination between the growth rate of cells, gravitational constant and Planck constant gives equations with dimension of mass M(vgr)=(h.vgr/G)½ in kg, length L(v gr)=(hṡG/vgr3)1/2 in meter, time T(vgr)=(hṡG/vgr5)1/2 in seconds, and density ρ ((vgr)=vgr.3.5/hG2 in kg/m3 . For growth rate vgr in diapason of 1×10-11 m/s - 1×10-9.5 m/s the calculated numerical values for mass (3×10-18 -1×10-16 kg), length (5×10-8 -1×10-5 m), time (1×102 -1×106 s) and density (1×10-1 - 1×104 kg/m3) overlaps with diapason of experimentally measured values for cell mass (3×10-18 -1×10-15 kg), volume to surface ratio (1×10-7 -1×10-4 m), doubling time (1×103 -1×107 s), and density (1050 - 1300 kg/m3) in bacteria and protozoa. These equations show that appearance of the first living cells could be mutually connected to the physical constants.
Cosmological variation of the MOND constant: secular effects on galactic systems
Milgrom, Mordehai
2014-01-01
The proximity of the MOND acceleration constant with cosmological accelerations -- for example, a0~ cH0/2pi -- points to its possibly decreasing with cosmic time. I begin to consider the secular changes induced in galactic systems by such presumed variations, assumed adiabatic. It is important to understand these effects, in isolation from other evolutionary influences, in order to identify or constrain a0 variations by detection of induced effects, or lack thereof. I find that as long as the system is fully in the deep-MOND regime -- as applies to many galactic systems -- the adiabatic response of the system obeys simple scaling laws. For example, in a system that would be stationary for fixed a0, the system expands homologously as a0^{-1/4}, while internal velocities decrease uniformly as a0^{1/4}. If a0 is proportional to cH at all relevant times, this change amounts to a factor of ~ 2.5 since redshift 10. For a system stationary in a rotating frame, the angular frequency decreases as a0^{1/2}. The acceler...
Non-linear electrodynamics and the variation of the fine structure constant
Mbelek, Jean Paul; Mosquera Cuesta, Herman J.
2008-09-01
It has been claimed that during the late-time history of our Universe, the fine structure constant of electromagnetism, α, has been increasing. The conclusion is achieved after looking at the separation between lines of ions like CIV, MgII, SiII, FeII, among others in the absorption spectra of very distant quasars, and comparing them with their counterparts obtained in the laboratory. However, in the meantime, other teams have claimed either a null result or a decreasing α with respect to the cosmic time. Also, the current precision of laboratory tests does not allow one to either comfort or reject any of these astronomical observations. Here, we suggest that as photons are the sidereal messengers, a non-linear electrodynamics (NLED) description of the interaction of photons with the weak local background magnetic fields of a gas cloud absorber around the emitting quasar can reconcile the Chand et al. and Levshakov et al. findings with the negative variation found by Murphy et al. and Webb et al., and also to find a bridge with the positive variation argued more recently by Levshakov et al. We also show that NLED photon propagation in a vacuum permeated by a background magnetic field presents a full agreement with constraints from Oklo natural reactor data. Finally, we show that NLED may render a null result only in a narrow range of the local background magnetic field which should be the case of both the claims by Chand et al. and by Srianand et al.
Constraining the Variation in Fine-Structure Constant Using SDSS DR8 QSO Spectra
Rahmani, H; Srianand, R
2013-01-01
We report a robust constrain on the possible variation of fine-structure constant, alpha = e^2/(hbar*c), obtained using O III 4959,5007, nebular emission lines from QSOs. We find Delta-alpha/alpha=-(2.1 +/- 1.6) x 10^(-5) based on a well selected sample of 2347 QSOs from Sloan Digital Sky Survey Data Release 8 with 0.02 < z < 0.74. Our result is consistent with a non-varying alpha at a level of 2 x 10^(-5) over approximately 7 Gyr. This is the largest sample of extragalactic objects yet used to constrain the variation of alpha. While this constraint is not as stringent as those determined using many-multiplet method it is free from various systematic effects. A factor of ~ 4 improvement in Delta-alpha/alpha achieved here compared to the previous study (Bahcall et al. 2004) is just consistent with what is expected based on a factor of 14 times bigger sample used here. This suggests that errors are mainly dominated by the statistical uncertainty. We also find the ratio of transition probabilities correspo...
Higgs potential from extended Brans-Dicke theory and the time-evolution of the fundamental constants
Sola, Joan; Khodam-Mohammadi, A
2016-01-01
Despite the enormous significance of the Higgs potential in the context of the Standard Model of electroweak interactions and in Grand Unified Theories, its ultimate origin is fundamentally unknown and must be introduced by hand in accordance with the underlying gauge symmetry and the requirement of renormalizability. Here we propose a more physical motivation for the structure of the Higgs potential, which we link to gravity, and more specifically to an extended Brans-Dicke (BD) theory containing two interacting scalar fields. One of these fields is coupled to curvature as in the BD formulation, whereas the other is coupled to gravity both derivatively and non-derivatively through the curvature scalar and the Ricci tensor. By requiring that the cosmological solutions of the model are consistent with observations, we show that the effective scalar field potential adopts the Higgs potential form with a mildly time-evolving vacuum expectation value. Such residual vacuum dynamics could be responsible for the pos...
Kapelner, Adam; Krieger, Abba; Blanford, William J
2016-10-14
When measuring Henry's law constants (kH) using the phase ratio variation (PRV) method via headspace gas chromatography (GC), the value of kH of the compound under investigation is calculated from the ratio of the slope to the intercept of a linear regression of the inverse GC response versus the ratio of gas to liquid volumes of a series of vials drawn from the same parent solution. Thus, an experimenter collects measurements consisting of the independent variable (the gas/liquid volume ratio) and dependent variable (the GC(-1) peak area). A review of the literature found that the common design is a simple uniform spacing of liquid volumes. We present an optimal experimental design which estimates kH with minimum error and provides multiple means for building confidence intervals for such estimates. We illustrate performance improvements of our design with an example measuring the kH for Naphthalene in aqueous solution as well as simulations on previous studies. Our designs are most applicable after a trial run defines the linear GC response and the linear phase ratio to the GC(-1) region (where the PRV method is suitable) after which a practitioner can collect measurements in bulk. The designs can be easily computed using our open source software optDesignSlopeInt, an R package on CRAN.
Planck constraints on scalar-tensor cosmology and the variation of the gravitational constant
Ooba, Junpei; Chiba, Takeshi; Sugiyama, Naoshi
2016-01-01
Cosmological constraints on the scalar-tensor theory of gravity by analyzing the angular power spectrum data of the cosmic microwave background (CMB) obtained from the Planck 2015 results are presented. We consider the harmonic attractor model, in which the scalar field has a harmonic potential with curvature ($\\beta$) in the Einstein frame and the theory relaxes toward the Einstein gravity with time. Analyzing the ${\\it TT}$, ${\\it EE}$, and ${\\it TE}$ CMB data from Planck by the Markov Chain Monte Carlo method, we find that the present-day deviation from the Einstein gravity (${\\alpha_0}^2$) is constrained as ${\\alpha_0}^2<1.5\\times10^{-4-20\\beta^2}\\ (2\\sigma)$ and ${\\alpha_0}^2<2.0\\times10^{-3-20\\beta^2}\\ (4\\sigma)$ for $0<\\beta<0.45$. The time variation of the effective gravitational constant between the recombination and the present epochs is constrained as $G_{\\rm rec}/G_0<1.0030\\ (2\\sigma)$ and $G_{\\rm rec}/G_0<1.0067\\ (4\\sigma)$. We also find that the constraints are little affected ...
The Oklo bound on the time variation of the fine-structure constant revisited
Damour, Thibault Marie Alban Guillaume; Damour, Thibault; Dyson, Freeman
1996-01-01
It has been pointed out by Shlyakhter that data from the natural fission reactors which operated about two billion years ago at Oklo (Gabon) had the potential of providing an extremely tight bound on the variability of the fine-structure constant alpha. We revisit the derivation of such a bound by: (i) reanalyzing a large selection of published rare-earth data from Oklo, (ii) critically taking into account the very large uncertainty of the temperature at which the reactors operated, and (iii) connecting in a new way (using isotope shift measurements) the Oklo-derived constraint on a possible shift of thermal neutron-capture resonances with a bound on the time variation of alpha. Our final (95% C.L.) results are: -0.9 \\times 10^{-7} <(alpha^{Oklo} - alpha^{now})/alpha <1.2\\times 10^{-7} and -6.7 \\times 10^{-17} {yr}^{-1} < {\\dot alpha}^{averaged}/alpha <5.0\\times10^{-17} {yr}^{-1}.
Ivashchuk, V D
2015-01-01
A D-dimensional gravitational model with Gauss-Bonnet term is considered. When ansatz with diagonal cosmological type metrics is adopted, we find solutions with exponential dependence of scale factors (with respect to "synchronous-like" variable) which describe an exponential expansion of "our" 3-dimensional factor-space and obey the observational constraints on the temporal variation of effective gravitational constant G. Among them there are two exact solutions in dimensions D = 22, 28 with constant G and also an infinite series of solutions in dimensions D \\ge 2690 with the variation of G obeying the observational data.
The Von Kármán constant retrieved from CASES-97 dataset using a variational method
Directory of Open Access Journals (Sweden)
Y. Zhang
2008-12-01
Full Text Available A variational method is developed to retrieve the von Kármán constant κ from the CASES-97 dataset, collected near Wichita, Kansas, the United States from 6 April to 24 May 1997. In the variational method, a cost function is defined to measure the difference between observed and computed gradients of wind speed, air temperature and specific humidity. An optimal estimated von Kármán constant is obtained by minimizing the cost function through adjusting values of the von Kármán constant. Under neutral stratification, the variational analysis confirms the conventional value of κ (=0.40. For non-neutral stratification, however, κ varies with stability. The computational results show that the κ decreases monotonously from stable to unstable stratification. The variational calculated mean value of the von Kármán constant is 0.383~0.390 when the atmospheric stratification is taken into consideration. Relations between κ and surface momentum and heat flux are also examined.
Avelino, P P
2016-01-01
We critically assess recent claims suggesting that upper limits on the time variation of the fine-structure constant tightly constrain the coupling of a dark energy scalar field to the electromagnetic sector, and, indirectly, the violation of the weak equivalence principle. We show that such constraints depend crucially on the assumed priors, even if the dark energy was described by a dynamical scalar field with a constant equation of state parameter $w$ linearly coupled to the electromagnetic sector through a dimensionless coupling $\\zeta$. We find that, although local atomic clock tests, as well as other terrestrial, astrophysical and cosmological data, put stringent bounds on $|\\zeta| {\\sqrt {|w+1|}}$, the time variation of the fine-structure constant cannot be used to set or to improve upper limits on $|\\zeta|$ or $|w+1|$ without specifying priors, consistent but not favoured by current data, which strongly disfavour low values of $|w+1|$ or $|\\zeta|$, respectively. We briefly discuss how this might chang...
Time-Variation of the Gravitational Constant and the Machian Solution in the Brans-Dicke Theory
Miyazaki, A
2001-01-01
The Machian cosmological solution satisfying $\\phi =O(\\rho /\\omega)$ for the perfect-fluid with negative pressure is discussed. When the coefficient of the equation of state $\\gamma \\to -1/3$, the gravitational constant approaches to constant. If we assume the present mass density $\\rho_{0}\\sim \\rho_{c}$ (critical density), the parameter $\\epsilon$ ($\\gamma =(\\epsilon -1)/3$) has a value of order $10^{-3}$ to support the present gravitational constant. The closed model is valid for $\\omega <-3/2\\epsilon$ and exhibits the slow accelerating expansion. We understand why the coupling parameter $| \\omega |$ is so large ($\\omega \\sim -10^{3}$). The time-variation of the gravitational constant $| \\dot{G}/G| \\sim 10^{-13} yr^{-1}$ at present is derived in this model.
Nakashima, Masahiro; Nagata, Ryo; Yokoyama, Jun'ichi
2009-01-01
We investigate constraints on the time variation of the fine structure constant between the recombination epoch and the present epoch, $\\Delta\\alpha/\\alpha \\equiv (\\alpha_{rec} - \\alpha_{now})/\\alpha_{now}$, from cosmic microwave background (CMB) taking into account simultaneous variation of other physical constants, namely the electron mass $m_{e}$ and the proton mass $m_{p}$. In other words, we consider the variation of Yukawa coupling and the QCD scale $\\Lambda_{QCD}$ in addition to the electromagnetic coupling. We clarify which parameters can be determined from CMB temperature anisotropy in terms of singular value decomposition. Assuming a relation among variations of coupling constants governed by a single scalar field (the dilaton), the 95 % confidence level (C.L.) constraint on $\\Delta\\alpha/\\alpha$ is found to be $-8.28 \\times 10^{-3} < \\Delta\\alpha/\\alpha < 1.81 \\times 10^{-3}$, which is tighter than the one obtained by considering only the change of $\\alpha$ and $m_{e}$. We also obtain the con...
Directory of Open Access Journals (Sweden)
Marius Vasile GHIURCAU
2010-01-01
Full Text Available Telephone banking or brokering, building accesssystems or forensics are some of the areas in which speakerrecognition is continuously developing. Fundamental frequencyrepresents an important speech feature used in theseapplications. In this paper we present a study of the effect ofemotional state of a speaker upon the variation of thefundamental frequency of the speech signal. Human beings arequite frequently overwhelmed by various emotions and most ofthe time one can not really control these emotional states. Forthe purpose of our work we have used the Berlin emotionalspeech database which contains utterances of 10 speakers indifferent emotional situations: happy, angry, fearful, bored andneutral. The mean fundamental frequency and also the standarddeviation for every speaker in all the emotional states werecomputed. The results show a very strong influence of theemotional state upon frequency variation.
Ganguly, Gaurab; Mukherjee, Manas; Paul, Ankan
2014-01-01
Based on the spectroscopic constants derived from highly accurate potential energy surfaces, the SeD radical is identified as a spectroscopic probe for measuring spatial and temporal variation of fundamental physical constants such as the fine-structure constant (denoted as $\\alpha=\\frac{e^2}{\\hbar c}$) and the proton-to-electron mass ratio (denoted as $\\mu=\\frac{m_p}{m_e}$). The ground state of SeD ($X^2\\Pi$), due to spin-orbit coupling, splits into two fine structure multiplets $^2\\Pi_{\\frac{3}{2}}$ and $^2\\Pi_{\\frac{1}{2}}$. The potential energy surfaces of these spin-orbit components are derived from a state of the art electronic structure method, MRCI+Q inclusive of scalar relativistic effects with the spin-orbit effects accounted through the Breit-Pauli operator. The relevant spectroscopic data are evaluated using Murrel-Sorbie fit to the potential energy surfaces. The spin-orbit splitting($\\omega_f$) between the two multiplets is similar in magnitude with the harmonic frequency ($\\omega_e$) of the diat...
Baldacci, A.; Stoppa, P.; Visinoni, R.; Wugt Larsen, R.
2012-09-01
The high resolution infrared absorption spectrum of CH2D81Br has been recorded by Fourier transform spectroscopy in the range 550-1075 cm-1, with an unapodized resolution of 0.0025 cm-1, employing a synchrotron radiation source. This spectral region is characterized by the ν6 (593.872 cm-1), ν5 (768.710 cm-1) and ν9 (930.295 cm-1) fundamental bands. The ground state constants up to sextic centrifugal distortion terms have been obtained for the first time by ground-state combination differences from the three bands and subsequently employed for the evaluation of the excited state parameters. Watson's A-reduced Hamiltonian in the Ir representation has been used in the calculations. The ν 6 = 1 level is essentially free from perturbation whereas the ν 5 = 1 and ν 9 = 1 states are mutually interacting through a-type Coriolis coupling. Accurate spectroscopic parameters of the three excited vibrational states and a high-order coupling constant which takes into account the interaction between ν5 and ν9 have been determined.
Temperature variation of higher-order elastic constants of MgO
Indian Academy of Sciences (India)
K M Raju; R K Srivastava; Kailash
2007-09-01
An effort has been made for obtaining higher-order elastic constants for MgO starting from basic parameters, viz. nearest-neighbor distance and hardness parameter using Coulomb and Börn–Mayer potentials. These are calculated in a wide temperature range (100–1000 K) and compared with available theoretical and experimental results.
Variation of the Gravitational Constant in the Radiation-Dominated Universe
Directory of Open Access Journals (Sweden)
L. L. Williams
2012-01-01
Full Text Available The unification of classical electrodynamics and general relativity within the context of five-dimensional general relativity (Kaluza, 1921, and Thiry, 1948 contains a scalar field which may be identified with the gravitational constant, G. The field equations of this theory are solved under conditions of the Robertson-Walker metric for flat space, for a radiation-dominated universe—a model appropriate for the early history of our universe. This leads to a cosmology wherein G is inversely proportional to the Robertson-Walker scale factor. This result is discussed in the context of the Dirac large number hypothesis and in the context of an expression for G in terms of atomic constants.
Variation of fundamental parameters and dark energy. A principal component approach
Amendola, L; Martins, C J A P; Nunes, N J; Pedrosa, P O J; Seganti, A
2011-01-01
We discuss methods based on Principal Component Analysis for reconstructing the dark energy equation of state and constraining its evolution, using a combination of Type Ia supernovae at low redshift and spectroscopic measurements of varying fundamental couplings at higher redshifts. We discuss the performance of this method when future better-quality datasets are available, focusing on two forthcoming ESO spectrographs -- ESPRESSO for the VLT and CODEX for the E-ELT -- which include these measurements as a key part of their science cases. These can realize the prospect of a detailed characterization of dark energy properties all the way up to redshift 4.
Cameron, Ewan
2012-01-01
We review the evidence behind recent claims of spatial variation in the fine structure constant deriving from observations on ground-based telescopes of ionic absorption lines in the light from distant quasars. To this end we expand upon previous non-Bayesian analyses limited by the assumptions of a strictly Normal and unbiased form for the "unexplained errors" of the benchmark quasar dataset. Through nested importance sampling and the method of power posteriors we evaluate and compare marginal likelihoods (or Bayes factors) for three competing hypotheses-(i) the strict null (no cosmic variation), (ii) the monopole null (a constant Earth-to-quasar offset only), and (iii) the monopole+dipole hypothesis (featuring a cosmic variation manifest to the Earth-bound observer as a North-South divergence)-under various alternative error terms. Our analysis reveals significant support for a skeptical interpretation in which the apparent dipole effect is driven solely by systematic errors of opposing sign inherent in mea...
Huang, Daoming; Chen, Zhongming
2010-01-01
Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx (OH and HO2) radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry's law constant (K(H)), significantly influences its role in atmospheric processes. Large discrepancies between the K(H) values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of K(H) for hydrogen peroxide at an air pressure of (0.960 +/- 0.013) atm (1 atm = 1.01325 x 10(5) Pa). The results indicated that the temperature dependence of K(H) for hydrogen peroxide fits to the Van't Hoff equation form, expressed as lnK(H) = a/T - b, and a = -deltaH/R, where K(H) is in M/atm (M is mol/L), T is in degrees Kelvin, R is the ideal gas constant, and deltaH is the standard heat of solution. For acidity dependence, results demonstrated that the K(H) value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level (from pH 7 to pH 1). Combining the dependence of both temperature and acidity, the obtained a and b were 7024 +/- 138 and 11.97 +/- 0.48, respectively, deltaH was (58.40 +/- 1.15) kJ/(K x mol), and the uncertainties represent sigma. Our determined K(H) values for hydrogen peroxide will therefore be of great use in atmospheric models.
Berengut, J C; Dzuba, V A; Flambaum, V V; Ong, A
2012-08-17
We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, α. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf(16+) is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf(16+) has very large nuclear charge and large ionization energy, resulting in the largest α sensitivity seen in atomic systems. The lines include positive and negative shifters.
Bound on the variation in the fine structure constant implied by Oklo data
Hamdan, Leila
2015-01-01
Dynamical models of dark energy can imply that the fine structure constant $\\alpha$ varies over cosmological time scales. Data on shifts in resonance energies $E_r$ from the Oklo natural fission reactor have been used to place restrictive bounds on the change in $\\alpha$ over the last 1.8 billion years. We review the uncertainties in these analyses, focussing on corrections to the standard estimate of $k_\\alpha\\!=\\!\\alpha\\,dE_r/d\\alpha$ due to Damour and Dyson. Guided, in part, by the best practice for assessing systematic errors in theoretical estimates spelt out by Dobaczewski et al. [in J. Phys. G: Nucl. Part. Phys. 41, 074001 (2014)], we compute these corrections in a variety of models tuned to reproduce existing nuclear data. Although the net correction is uncertain to within a factor of 2 or 3, it constitutes at most no more than 25% of the Damour-Dyson estimate of $k_\\alpha$. Making similar allowances for the uncertainties in the modeling of the operation of the Oklo reactors, we conclude that the rela...
Copy number variation is a fundamental aspect of the placental genome.
Hannibal, Roberta L; Chuong, Edward B; Rivera-Mulia, Juan Carlos; Gilbert, David M; Valouev, Anton; Baker, Julie C
2014-05-01
Discovery of lineage-specific somatic copy number variation (CNV) in mammals has led to debate over whether CNVs are mutations that propagate disease or whether they are a normal, and even essential, aspect of cell biology. We show that 1,000 N polyploid trophoblast giant cells (TGCs) of the mouse placenta contain 47 regions, totaling 138 Megabases, where genomic copies are underrepresented (UR). UR domains originate from a subset of late-replicating heterochromatic regions containing gene deserts and genes involved in cell adhesion and neurogenesis. While lineage-specific CNVs have been identified in mammalian cells, classically in the immune system where V(D)J recombination occurs, we demonstrate that CNVs form during gestation in the placenta by an underreplication mechanism, not by recombination nor deletion. Our results reveal that large scale CNVs are a normal feature of the mammalian placental genome, which are regulated systematically during embryogenesis and are propagated by a mechanism of underreplication.
Copy number variation is a fundamental aspect of the placental genome.
Directory of Open Access Journals (Sweden)
Roberta L Hannibal
2014-05-01
Full Text Available Discovery of lineage-specific somatic copy number variation (CNV in mammals has led to debate over whether CNVs are mutations that propagate disease or whether they are a normal, and even essential, aspect of cell biology. We show that 1,000 N polyploid trophoblast giant cells (TGCs of the mouse placenta contain 47 regions, totaling 138 Megabases, where genomic copies are underrepresented (UR. UR domains originate from a subset of late-replicating heterochromatic regions containing gene deserts and genes involved in cell adhesion and neurogenesis. While lineage-specific CNVs have been identified in mammalian cells, classically in the immune system where V(DJ recombination occurs, we demonstrate that CNVs form during gestation in the placenta by an underreplication mechanism, not by recombination nor deletion. Our results reveal that large scale CNVs are a normal feature of the mammalian placental genome, which are regulated systematically during embryogenesis and are propagated by a mechanism of underreplication.
Córsico, Alejandro H; García-Berro, Enrique; Romero, Alejandra D
2013-01-01
A secular variation of the gravitational constant modifies the structure and evolutionary time scales of white dwarfs. Using an state-of-the-art stellar evolutionary code and an up-to-date pulsational code we compute the effects of a secularly varying $G$ on the pulsational properties of variable white dwarfs. Comparing the the theoretical results obtained taking into account the effects of a running $G$ with the observed periods and measured rates of change of the periods of two well studied pulsating white dwarfs, G117--B15A and R548, we place constraints on the rate of variation of Newton's constant. We derive an upper bound $\\dot G/G\\sim -1.8\\times 10^{-10}$ yr$^{-1}$ using the variable white dwarf G117--B15A, and $\\dot G/G\\sim -1.3\\times 10^{-10}$ yr$^{-1}$ using R548. Although these upper limits are currently less restrictive than those obtained using other techniques, they can be improved in a future measuring the rate of change of the period of massive white dwarfs.
Gardner, C L
2003-01-01
Cosmological variation of the fine structure constant $\\alpha$ due to the evolution of a spatially homogeneous ultra-light scalar field ($m \\sim H_0$) during the matter and $\\Lambda$ dominated eras is analyzed. Agreement of $\\Delta \\alpha/\\alpha$ with the value suggested by recent observations of quasar absorption lines is obtained by adjusting a single parameter, the coupling of the scalar field to matter. Asymptotically $\\alpha(t)$ in this model goes to a constant value $\\bar{\\alpha} \\approx \\alpha_0$ in the early radiation and the late $\\Lambda$ dominated eras. The coupling of the scalar field to (nonrelativistic) matter drives $\\alpha$ slightly away from $\\bar{\\alpha}$ in the epochs when the density of matter is important. Simultaneous agreement with the more restrictive bounds on the variation $|\\Delta \\alpha/\\alpha|$ from the Oklo natural fission reactor and from meteorite samples can be achieved if the mass of the scalar field is on the order of 0.5--0.6 $\\bar{H}$, where $\\bar{H} = \\Omega_\\Lambda^{1/2}...
Energy Technology Data Exchange (ETDEWEB)
Córsico, Alejandro H.; Althaus, Leandro G. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, (1900) La Plata (Argentina); García-Berro, Enrique [Departament de Física Aplicada, Universitat Politècnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels (Spain); Romero, Alejandra D., E-mail: acorsico@fcaglp.unlp.edu.ar, E-mail: althaus@fcaglp.unlp.edu.ar, E-mail: enrique.garcia-berro@upc.edu, E-mail: alejandra.romero@ufrgs.br [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Porto Alegre 91501-970, RS (Brazil)
2013-06-01
A secular variation of the gravitational constant modifies the structure and evolutionary time scales of white dwarfs. Using an state-of-the-art stellar evolutionary code and an up-to-date pulsational code we compute the effects of a secularly varying G on the pulsational properties of variable white dwarfs. Comparing the the theoretical results obtained taking into account the effects of a running G with the observed periods and measured rates of change of the periods of two well studied pulsating white dwarfs, G117-B15A and R548, we place constraints on the rate of variation of Newton's constant. We derive an upper bound Ġ/G ∼ −1.8 × 10{sup −10} yr{sup −1} using the variable white dwarf G117-B15A, and Ġ/G ∼ −1.3 × 10{sup −10} yr{sup −1} using R548. Although these upper limits are currently less restrictive than those obtained using other techniques, they can be improved in a future measuring the rate of change of the period of massive white dwarfs.
Variational RRKM calculation of thermal rate constant for C–H bond fission reaction of nitro methane
Directory of Open Access Journals (Sweden)
Afshin Taghva Manesh
2017-02-01
Full Text Available The present work provides quantitative results for the rate constants of unimolecular C–H bond fission reactions in the nitro methane at elevated temperatures up to 2000 K. In fact, there are three different hydrogen atoms in the nitro methane. The potential energy surface for each C–H bond fission reaction of nitro methane was investigated by ab initio calculations. The geometry and vibrational frequencies of the species involved in this process were optimized at the MP2 level of theory, using the cc-pvdz basis set. Since C–H bond fission channel is a barrierless reaction, we have used variational RRKM theory to predict rate coefficients. By means of calculated rate coefficients at different temperatures, the Arrhenius expression of the channel over the temperature range of 100–2000 K is k(T = 5.9E19∗exp(−56274.6/T.
Kotuš, Srđan M; Carswell, Robert F
2016-01-01
The brightest southern quasar above redshift $z=1$, HE 0515$-$4414, with its strong intervening metal absorption-line system at $z_{abs}=1.1508$, provides a unique opportunity to precisely measure or limit relative variations in the fine-structure constant ($\\Delta\\alpha/\\alpha$). A variation of just $\\sim$3 parts per million (ppm) would produce detectable velocity shifts between its many strong metal transitions. Using new and archival observations from the Ultraviolet and Visual Echelle Spectrograph (UVES) we obtain an extremely high signal-to-noise ratio spectrum (peaking at S/N $\\approx250$ pix$^{-1}$). This provides the most precise measurement of $\\Delta\\alpha/\\alpha$ from a single absorption system to date, $\\Delta\\alpha/\\alpha=-1.42\\pm0.55_{\\rm stat}\\pm0.65_{\\rm sys}$ ppm, comparable with the precision from previous, large samples of $\\sim$150 absorbers. The largest systematic error in all (but one) previous similar measurements, including the large samples, was long-range distortions in the wavelengt...
Damour, Thibault Marie Alban Guillaume
2003-01-01
We review some string-inspired theoretical models which incorporate a correlated spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo; Rhenium decay) and with present equivalence principle tests. Barring unnatural fine-tunings of parameters, a variation of the fine-structure constant as large as that recently ``observed'' by Webb et al. in quasar absorption spectra appears to be incompatible with these phenomenological constraints. Independently of any model, it is emphasized that the best experimental probe of varying constants are high-precision tests of the universality of free fall, such as MICROSCOPE and STEP. Recent claims by Bekenstein that fine-structure-constant variability does not imply detectable violations of the equivalence principle are shown to be untenable.
Gershteyn, M L; Gershteyn, A; Karagioz, O V
2002-01-01
Remarks to solve disagreement between Gravity anisotropy observed at decimeter distances and constraints on the spatial variation of Gravitational constant (big G) based on gravimetric data and Lunar Laser Ranging (LLR) experiments. Disagreement disappears when we assume that Gravitational anisotropy may depend on the magnitudes of the interacting masses and the distance between them.
Kotuš, S. M.; Murphy, M. T.; Carswell, R. F.
2017-01-01
The brightest southern quasar above redshift z = 1, HE 0515-4414, with its strong intervening metal absorption line system at zabs = 1.1508, provides a unique opportunity to precisely measure or limit relative variations in the fine-structure constant (Δα/α). A variation of just ˜3 parts per million (ppm) would produce detectable velocity shifts between its many strong metal transitions. Using new and archival observations from the Ultraviolet and Visual Echelle Spectrograph (UVES), we obtain an extremely high signal-to-noise ratio spectrum (peaking at S/N ≈ 250 pix-1). This provides the most precise measurement of Δα/α from a single absorption system to date, Δα/α = -1.42 ± 0.55stat ± 0.65sys ppm, comparable with the precision from previous, large samples of ˜150 absorbers. The largest systematic error in all (but one) previous similar measurements, including the large samples, was long-range distortions in the wavelength calibration. These would add an ˜2 ppm systematic error to our measurement and up to ˜10 ppm to other measurements using Mg and Fe transitions. However, we corrected the UVES spectra using well-calibrated spectra of the same quasar from the High Accuracy Radial velocity Planet Searcher, leaving a residual 0.59 ppm systematic uncertainty, the largest contribution to our total systematic error. A similar approach, using short observations on future well-calibrated spectrographs to correct existing high S/N spectra, would efficiently enable a large sample of reliable Δα/α measurements. The high-S/N UVES spectrum also provides insights into analysis difficulties, detector artefacts and systematic errors likely to arise from 25-40-m telescopes.
Downey, Todd R.; Meriaudeau, Fabrice; Passian, Ali; Wig, Andrew; Ferrell, Thomas L.
1999-11-01
The effect of variation of core and cladding index difference, Δ n= ncore- ncladding, on allowable values for the guided mode transverse magnetic propagation constants within a step-index, multi-mode optical fiber is investigated. We use a iterative computational technique to calculate the propagation constants for modes inside and outside the core that satisfy the boundary conditions contained within the characteristic eigen-equation for the TM field components. Evidence of a strong dependence of the allowable propagation constants on changes of Δ n is shown.
Bao, Junwei Lucas; Zhang, Xin; Truhlar, Donald G
2016-06-22
Understanding the falloff in rate constants of gas-phase unimolecular reaction rate constants as the pressure is lowered is a fundamental problem in chemical kinetics, with practical importance for combustion, atmospheric chemistry, and essentially all gas-phase reaction mechanisms. In the present work, we use our recently developed system-specific quantum RRK theory, calibrated by canonical variational transition state theory with small-curvature tunneling, combined with the Lindemann-Hinshelwood mechanism, to model the dissociation reaction of fluoroform (CHF3), which provides a definitive test for falloff modeling. Our predicted pressure-dependent thermal rate constants are in excellent agreement with experimental values over a wide range of pressures and temperatures. The present validation of our methodology, which is able to include variational transition state effects, multidimensional tunneling based on the directly calculated potential energy surface along the tunneling path, and torsional and other vibrational anharmonicity, together with state-of-the-art reaction-path-based direct dynamics calculations, is important because the method is less empirical than models routinely used for generating full mechanisms, while also being simpler in key respects than full master equation treatments and the full reduced falloff curve and modified strong collision methods of Troe.
Diolaiuti, G.; D'Agata, C.; Stella, G.; Apadula, F.; Smiraglia, C.
This paper introduces the preliminary results of a project applied primarily to the compilation of the first general and complete data-base of all Italian glaciers, avail- able to the scientific community, and secondly to the elaboration of the information contained in the data base to supply a strong contribution to the study of the spatial and temporal variabilities of the climatic signal inside the alpine glacier historical series. The project started in the year 2000 as a convention between Università degli Studi di Milano (Italy) and CESI (Italian Electrical Sperimental Center) and gives the first results and the free use by people in the 2002, the International Year of Mountains. Fundamental for the development of the project was the collaboration of the Italian Glaciological Committee (CGI) with its publications (from 1914 to 1977 SBollettino & cedil;del Comitato Glaciologico ItalianoT and from 1978 to 2000 SGeografia Fisica e Di- & cedil;namica Quaternaria). The data-base collects qualitative and quantitative information on glaciers monitored by the Italian Glaciological CommitteeSs operators during the century of their activity for a total of 902 glaciers (901 alpine glaciers and only Ap- pennine one, the Calderone Glacier). For every glacier were inserted in the data-base: 1) data about the glacial terminus elevations, date and method of the measure 2) name and position of the signals used by the operators in order to verify the variations of extension of glacial terminus 3) distance between the signal and the glacier terminus and relative angle of measure 4) operatorSs name 5) bibliographical source of the information 6) qualitative data (on cartographic material, photographies and papers). Currently only a part of the data collected in the data-base is directly available in the web site: www.cesi.it/greeninfo/i ghiacciai Italiani/. Here the users are able to find, for every glacier, a table with all the references of qualitative (as cartography and
Padidhapu, Rajendra; Brahmajirao, V
2016-01-01
We consider a coupled system of Navier Stokes, Maxwell Stefan and Poisson Boltzmann equations by incorporating the variation of dielectric constant, which governs the electro osmotic flow in nano channel, describing the evolution of the velocity, concentration and potential fields of dissolved constituents in an aqueous electrolyte solution. We apply the finite difference technique to solve one and two dimensional systems of these equations. The solutions give an extremely accurate prediction of the dielectric constant for a variety of salts and a wide range of concentrations.
Dzuba, V A; Flambaum, V V
2012-01-01
We study ultranarrow $5s_{1/2}$ - $4f_{5/2}$ transitions in Nd$^{13+}$ and Sm$^{15+}$ and demonstrate that they lie in the optical region. The transitions are insensitive to external perturbations. At the same time they are sensitive to the variation of the fine structure constant $\\alpha$. The fractional accuracy of the frequency of the transitions can be smaller than $10^{-19}$, which may provide a basis for atomic clocks of superb accuracy. Sensitivity to the variation of $\\alpha$ approaches $10^{-20}$ per year.
Fundamental physics in particle traps
Vogel, Manuel
2014-01-01
This volume provides detailed insight into the field of precision spectroscopy and fundamental physics with particles confined in traps. It comprises experiments with electrons and positrons, protons and antiprotons, antimatter and highly charged ions, together with corresponding theoretical background. Such investigations represent stringent tests of quantum electrodynamics and the Standard model, antiparticle and antimatter research, test of fundamental symmetries, constants, and their possible variations with time and space. They are key to various aspects within metrology such as mass measurements and time standards, as well as promising to further developments in quantum information processing. The reader obtains a valuable source of information suited for beginners and experts with an interest in fundamental studies using particle traps.
Fundamental ecology is fundamental.
Courchamp, Franck; Dunne, Jennifer A; Le Maho, Yvon; May, Robert M; Thébaud, Christophe; Hochberg, Michael E
2015-01-01
The primary reasons for conducting fundamental research are satisfying curiosity, acquiring knowledge, and achieving understanding. Here we develop why we believe it is essential to promote basic ecological research, despite increased impetus for ecologists to conduct and present their research in the light of potential applications. This includes the understanding of our environment, for intellectual, economical, social, and political reasons, and as a major source of innovation. We contend that we should focus less on short-term, objective-driven research and more on creativity and exploratory analyses, quantitatively estimate the benefits of fundamental research for society, and better explain the nature and importance of fundamental ecology to students, politicians, decision makers, and the general public. Our perspective and underlying arguments should also apply to evolutionary biology and to many of the other biological and physical sciences. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.
Lakshmi Madhuri, P.; Krishna Prasad, S.; Shinde, Pravin; Prasad, B. L. V.
2016-10-01
We report measurements of splay and bend Frank elastic constants in a composite comprising a nematic liquid crystal doped with a small concentration of sterically stabilized gold nanorods. The composite exhibits not only a large reduction in the magnitude of the threshold voltage for switching (V th, 20%), as well as of the splay (K 11, 40%) and bend (K 33, 40%) elastic constants, but also presents an unprecedented feature: a substantial diminution in the temperature dependence of these parameters, almost to the point of becoming thermally invariant. This observation is significant because the electro-optic switching of liquid-crystal devices is largely controlled by the K 11 and K 33 elastic constants. Electrical conductivity measurements also show interesting behavior upon the inclusion of nanorods. Whereas the intrinsic Arrhenius behavior governing the temperature dependence is enhanced, the frequency dependence shows qualitative features of Jonscher’s universal model, albeit with a higher exponent. Further, photoisomerization of an azobenzene guest component provides an additional influence on the elastic constants. The results are discussed in terms of (a) the effect of the order parameter dependence seen from the viewpoint of an extended mean-field model, and (b) local order. The advantage of incorporating nanorods with photofunctionality is also pointed out.
DEFF Research Database (Denmark)
Svendsen, Morten Bo Søndergaard; Bushnell, P.G.; Christensen, Emil Aputsiaq Flindt
2016-01-01
consumption rates (M˙O2 ) of a fish, by continuously injecting anoxic water into a respirometer, altering the injection rate to correct for the washout error. The effect of respirometer-to-fish volume ratio (RFR) on SMR measurement and variability was also investigated, using the simulated constant M˙O2...... oxygen consumption rates of fishes in systems with reasonable RFRs mainly comes from the animal, not from the measuring equipment....
Fundamental constants: The teamwork of precision
Myers, Edmund G.
2014-02-01
A new value for the atomic mass of the electron is a link in a chain of measurements that will enable a test of the standard model of particle physics with better than part-per-trillion precision. See Letter p.467
Ohki, Kaori; Gantt, Elisabeth; Lipschultz, Claudia A.; Ernst, Marjorie C.
1985-01-01
Phycobilisomes of Tolypothrix tenuis, a cyanobacterium capable of complete chromatic adaptation, were studied from cells grown in red and green light, and in darkness. The phycobilisome size remained constant irrespective of the light quality. The hemidiscoidal phycobilisomes had an average diameter of about 52 nanometers and height of about 33 nanometers, by negative staining. The thickness was equivalent to a phycocyanin molecule (about 10 nanometers). The molar ratio of allophycocyanin, relative to other phycobiliproteins always remained at about 1:3. Phycobilisomes from red light grown cells and cells grown heterotrophically in darkness were indistinguishable in their pigment composition, polypeptide pattern, and size. Eight polypeptides were resolved in the phycobilin region (17.5 to 23.5 kilodaltons) by isoelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Half of these were invariable, while others were variable in green and red light. It is inferred that phycoerythrin synthesis in green light resulted in a one for one substitution of phycocyanin, thus retaining a constant phycobilisome size. Tolypothrix appears to be one of the best examples of phycobiliprotein regulation with wavelength. By contrast, in Nostoc sp., the decrease in phycoerythrin in red light cells was accompanied by a decrease in phycobilisome size but not a regulated substitution. Images Fig. 1 Fig. 2 Fig. 4 PMID:16664550
Antoine, Jean-Yves; Villaneau, Jeanne; Goulian, Jérôme
2012-01-01
International audience; This paper presents a corpus study on word order variations (WOV) in spontaneous spoken French. We have studied several corpus of spoken dialogue dedicated to different tasks to assess the influence of the discourse context on WOVs. At first, we show how the contribution of pilot corpus studies should benefit to Natural Language Processing researches. Then, we present our methodology and the main results of this study. In particular, we observe that the task and the ro...
Varying Constants, Gravitation and Cosmology
Directory of Open Access Journals (Sweden)
Jean-Philippe Uzan
2011-03-01
Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Varying Constants, Gravitation and Cosmology.
Uzan, Jean-Philippe
2011-01-01
Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Varying Constants, Gravitation and Cosmology
Uzan, Jean-Philippe
2011-12-01
Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Fundamentally updating fundamentals.
Armstrong, Gail; Barton, Amy
2013-01-01
Recent educational research indicates that the six competencies of the Quality and Safety Education for Nurses initiative are best introduced in early prelicensure clinical courses. Content specific to quality and safety has traditionally been covered in senior level courses. This article illustrates an effective approach to using quality and safety as an organizing framework for any prelicensure fundamentals of nursing course. Providing prelicensure students a strong foundation in quality and safety in an introductory clinical course facilitates early adoption of quality and safety competencies as core practice values.
Nguyen, A T; Lamoreaux, S K; Torgerson, J R
2003-01-01
It has been proposed that the radio-frequency electric-dipole (E1) transition between two nearly degenerate opposite-parity states in atomic dysprosium should be highly sensitive to possible temporal variation of the fine structure constant ($\\alpha$) [V. A. Dzuba, V. V. Flambaum, and J. K. Webb, Phys. Rev. A {\\bf 59}, 230 (1999)]. We discuss here an experimental realization of the proposed search, which involves monitoring the E1 transition frequency over a period of time using direct frequency counting techniques. We estimate that a statistical sensitivity of $|\\adota| \\sim 10^{-18}$/yr may be achieved and discuss possible systematic effects in such a measurement.
Strain-induced phase variation and dielectric constant enhancement of epitaxial Gd{sub 2}O{sub 3}
Energy Technology Data Exchange (ETDEWEB)
Shekhter, P., E-mail: Pini@tx.technion.ac.il; Amouyal, Y.; Eizenberg, M. [Department of Materials Science and Engineering, Technion–Israel Institute of Technology, Haifa 32000 (Israel); Schwendt, D.; Wietler, T. F.; Osten, H. J. [Institute of Electronic Materials and Devices, Leibniz University of Hannover, Schneiderberg 32, 30167 Hannover (Germany)
2016-07-07
One of the approaches for realizing advanced high k insulators for metal oxide semiconductor field effect transistors based devices is the use of rare earth oxides. When these oxides are deposited as epitaxial thin films, they demonstrate dielectric properties that differ greatly from those that are known for bulk oxides. Using structural and spectroscopic techniques, as well as first-principles calculations, Gd{sub 2}O{sub 3} films deposited on Si (111) and Ge (111) were characterized. It was seen that the same 4 nm thick film, grown simultaneously on Ge and Si, presents an unstrained lattice on Ge while showing a metastable phase on Si. This change from the cubic lattice to the distorted metastable phase is characterized by an increase in the dielectric constant of more than 30% and a change in band gap. The case in study shows that extreme structural changes can occur in ultra-thin epitaxial rare earth oxide films and modify their dielectric properties when the underlying substrate is altered.
Chand, H; Srianand, R; Aracil, B; Chand, Hum; Petitjean, Patrick; Srianand, Raghunathan; Aracil, Bastien
2004-01-01
We report a new constraint on the variation of the fine-structure constant based on the analysis of 15 Si IV doublets selected from a ESO-UVES sample. We find \\Delta\\alpha/\\alpha= +(0.15 +/- 0.43) 10^{-5} over a redshift range of 1.59< z < 2.92 which is consistent with no variation in \\alpha. This result represents a factor three improvement on the constraint on \\Delta\\alpha/\\alpha based on Si IV doublets compared to the published results in the literature. Alkali doublet method used here avoids the implicit assumptions used in the many-multiplet method that chemical and ionization homogeneities are negligible and isotopic abundances are close to the terrestrial value.
Albareti, Franco D; Gutiérrez, Carlos M; Prada, Francisco; Pâris, Isabelle; Schlegel, David; López-Corredoira, Martín; Schneider, Donald P; Manchado, Arturo; García-Hernández, D A; Petitjean, Patrick; Ge, Jian
2015-01-01
From the Sloan Digital Sky Survey Data Release 12, which covers the full Baryonic Oscillation Spectroscopic Survey (BOSS) footprint, we investigate the possible variation of the fine-structure constant over cosmological time scales. We analyze the largest quasar sample considered so far in the literature, which contains 10,363 spectra with $z<1$. All the BOSS quasar spectra are selected from a visually inspected quasar catalog. We apply the emission line method on the [O III] doublet (4960, 5008 A) and obtain $\\Delta\\alpha/\\alpha= \\left(1.4 \\pm 2.3\\right)\\times10^{-5}$ for the relative variation of the fine-structure constant. We also investigate the possible sources of systematics: misidentification of the lines, sky OH lines, H$\\beta$ and broad line contamination, optimal wavelength range for the Gaussian fits, chosen polynomial order for the continuum spectrum, signal-to-noise ratio and good quality of the fits. The uncertainty of the measurement is dominated by the sky subtraction. The results presente...
Miché, F; Vivien-Roels, B; Pévet, P; Spehner, C; Robin, J P; Le Maho, Y
1991-11-01
Daily variations in circulating melatonin concentrations have been measured at monthly intervals from April to December 1986 in an Antarctic bird, the emperor penguin, Aptenodytes forsteri, maintained under natural conditions. Both duration of the elevated nighttime melatonin levels and amplitude of the day-night rhythm displays an annual variation closely related to variations in the daylength. Duration of the nocturnal peak of melatonin secretion depended upon the duration of the darkness, decreasing with increasing daylength and disappearing completely during the summer solstice. The duration of the nighttime melatonin peak melatonin increased inversely with decreasing daylength. The amplitude of the day-night rhythm decreased in such a way that the nocturnal peak of melatonin completely disappeared during the winter solstice. Three days of constant illumination in September did not suppress the nighttime peak of melatonin secretion. The response of melatonin secretion, decreasing after beta-adrenergic agonist treatment and increasing after antagonist treatment, reinforces the hypothesis that in birds the regulation of melatonin synthesis differs from that of the rat. Receptors other than beta receptors may be involved.
Cameron, Ewan
2013-01-01
In the second paper of this series we extend our Bayesian reanalysis of the evidence for a cosmic variation of the fine structure constant to the semi-parametric modelling regime. By adopting a mixture of Dirichlet processes prior for the unexplained errors in each instrumental subgroup of the benchmark quasar dataset we go some way towards freeing our model selection procedure from the apparent subjectivity of a fixed distributional form. Despite the infinite-dimensional domain of the error hierarchy so constructed we are able to demonstrate a recursive scheme for marginal likelihood estimation with prior-sensitivity analysis directly analogous to that presented in Paper I, thereby allowing the robustness of our posterior Bayes factors to hyper-parameter choice and model specification to be readily verified. In the course of this work we elucidate various similarities between unexplained error problems in the seemingly disparate fields of astronomy and clinical meta-analysis, and we highlight a number of sop...
Nandy, D. K.; Sahoo, B. K.
2016-09-01
Transitions among the first three low-lying states in the highly charged W+13, Ir+16, and Pt+17 ions are found to be strongly forbidden with wavelengths in the optical regime. By determining their energy levels, lifetimes, and other spectroscopic properties that are decisive quantities for estimating dominant systematics due to stray electromagnetic interactions in an experiment, we demonstrate that it can be possible to measure frequencies of the lowest forbidden transitions below a 10-19 precision level in the above ions, and hence, they seem to be suitable for frequency standards. We employ a sophisticated relativistic coupled cluster method to carry out calculations of these properties of the above states involving 4 f - and 5 s -core orbitals. We also found, by estimating their relativistic sensitivity coefficients, that these clock transitions can be highly sensitive to the tiny drift in the fine-structure constant αe. Consequently, a clock based on one of these ions, particularly Pt+17, could be used for corroborating the hypothesis of temporal and spatial variation in αe.
Quantum Theory without Planck's Constant
Ralston, John P
2012-01-01
Planck's constant was introduced as a fundamental scale in the early history of quantum mechanics. We find a modern approach where Planck's constant is absent: it is unobservable except as a constant of human convention. Despite long reference to experiment, review shows that Planck's constant cannot be obtained from the data of Ryberg, Davisson and Germer, Compton, or that used by Planck himself. In the new approach Planck's constant is tied to macroscopic conventions of Newtonian origin, which are dispensable. The precision of other fundamental constants is substantially improved by eliminating Planck's constant. The electron mass is determined about 67 times more precisely, and the unit of electric charge determined 139 times more precisely. Improvement in the experimental value of the fine structure constant allows new types of experiment to be compared towards finding "new physics." The long-standing goal of eliminating reliance on the artifact known as the International Prototype Kilogram can be accompl...
Directory of Open Access Journals (Sweden)
Dr. Parmod Kumar
2014-01-01
Full Text Available In the present study the effect of variation of ionic strength of the medium on rate of oxidation of hydroxy benzoic acids as its effect provides some clues regarding the nature of reactive species involved in the rate determining step. In order to realize the above aim the experiments has been carried out which ultimately concluded that ionic strength variation does not change the reaction velocity constant significantly.
Hamilton City Board of Education (Ontario).
Suggestions for studying the topic of variation of individuals and objects (balls) to help develop elementary school students' measurement, comparison, classification, evaluation, and data collection and recording skills are made. General suggestions of variables that can be investigated are made for the study of human variation. Twelve specific…
Singh, Harjit
2011-01-01
""Radiology Fundamentals"" is a concise introduction to the dynamic field of radiology for medical students, non-radiology house staff, physician assistants, nurse practitioners, radiology assistants, and other allied health professionals. The goal of the book is to provide readers with general examples and brief discussions of basic radiographic principles and to serve as a curriculum guide, supplementing a radiology education and providing a solid foundation for further learning. Introductory chapters provide readers with the fundamental scientific concepts underlying the medical use of imag
Field Theory of Fundamental Interactions
Wang, Shouhong; Ma, Tian
2017-01-01
First, we present two basic principles, the principle of interaction dynamics (PID) and the principle of representation invariance (PRI). Intuitively, PID takes the variation of the action under energy-momentum conservation constraint. We show that the PID is the requirement of the presence of dark matter and dark energy, the Higgs field and the quark confinement. PRI requires that the SU(N) gauge theory be independent of representations of SU(N). It is clear that PRI is the logic requirement of any gauge theory. With PRI, we demonstrate that the coupling constants for the strong and the weak interactions are the main sources of these two interactions, reminiscent of the electric charge. Second, we emphasize that symmetry principles-the principle of general relativity and the principle of Lorentz invariance and gauge invariance-together with the simplicity of laws of nature, dictate the actions for the four fundamental interactions. Finally, we show that the PID and the PRI, together with the symmetry principles give rise to a unified field model for the fundamental interactions, which is consistent with current experimental observations and offers some new physical predictions. The research is supported in part by the National Science Foundation (NSF) grant DMS-1515024, and by the Office of Naval Research (ONR) grant N00014-15-1-2662.
Karttunen, Hannu; Oja, Heikki; Poutanen, Markku; Donner, Karl Johan
2007-01-01
Fundamental Astronomy gives a well-balanced and comprehensive introduction to the topics of classical and modern astronomy. While emphasizing both the astronomical concepts and the underlying physical principles, the text provides a sound basis for more profound studies in the astronomical sciences. The fifth edition of this successful undergraduate textbook has been extensively modernized and extended in the parts dealing with the Milky Way, extragalactic astronomy and cosmology as well as with extrasolar planets and the solar system (as a consequence of recent results from satellite missions and the new definition by the International Astronomical Union of planets, dwarf planets and small solar-system bodies). Furthermore a new chapter on astrobiology has been added. Long considered a standard text for physical science majors, Fundamental Astronomy is also an excellent reference and entrée for dedicated amateur astronomers.
Energy Technology Data Exchange (ETDEWEB)
Robinson, H.P.; Potter, Elinor
1971-03-01
This collection of mathematical data consists of two tables of decimal constants arranged according to size rather than function, a third table of integers from 1 to 1000, giving some of their properties, and a fourth table listing some infinite series arranged according to increasing size of the coefficients of the terms. The decimal values of Tables I and II are given to 20 D.
Sparavigna, Amelia Carolina
2012-01-01
As proposed in a previous paper, the decorations of ancient objects can provide some information on the approximate evaluations of constant {\\pi}, the ratio of circumference to diameter. Here we discuss some disks found in the tomb of Hemaka, the chancellor of a king of the First Dynasty of Egypt, about 3000 BC. The discussion is based on measurements of the dimensionless ratio of lengths.
On the Stability of Fundamental Couplings in the Galaxy
João, S M; Mota, I S A B; Vianez, P M T
2015-01-01
Astrophysical tests of the stability of Nature's fundamental couplings are a key probe of the standard paradigms in fundamental physics and cosmology. In this report we discuss updated constraints on the stability of the fine-structure constant $\\alpha$ and the proton-to-electron mass ratio $\\mu=m_p/m_e$ within the Galaxy. We revisit and improve upon the analysis by Truppe {\\it et al.} by allowing for the possibility of simultaneous variations of both couplings and also by combining them with the recent measurements by Levshakov {\\it et al.} By considering representative unification scenarios we find no evidence for variations of $\\alpha$ at the 0.4 ppm level, and of $\\mu$ at the 0.6 ppm level; if one uses the Levshakov bound on $\\mu$ as a prior, the$\\alpha$ bound is improved to 0.1 ppm. We also highlight how these measurements can constrain (and discriminate among) several fundamental physics paradigms.
Constraining the fundamental interactions and couplings with Eoetvoes experiments
Energy Technology Data Exchange (ETDEWEB)
Kraiselburd, Lucila, E-mail: lkrai@fcaglp.fcaglp.unlp.edu.ar [Grupo de Gravitacion, Astrofisica y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N (1900) La Plata (Argentina); Vucetich, Hector, E-mail: vucetich@fcaglp.unlp.edu.ar [Grupo de Gravitacion, Astrofisica y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N (1900) La Plata (Argentina)
2012-11-15
Upper bounds for the violation of the Weak Equivalence Principle (WEP) by the fundamental interactions have been given before. We now recompute the limits on the parameters measuring the strength of the violation with the whole set of high accuracy Eoetvoes experiments. Besides, limits on spatial variation of the fundamental constants {alpha}, sin{sup 2}{theta}{sub W} and v, the vacuum expectation value of the Higgs field, are found in a model independent way. Limits on other parameters in the gauge sector are also found from the structure of the Standard Model.
Directory of Open Access Journals (Sweden)
G. T. Kulakov
2008-01-01
Full Text Available The paper is devoted to computational investigation of influence relative time constant of an object which changes in broad band on quality of steam temperature control behind a boiler with due account of value of regulating action in the system with PI- and PID- regulator. The simulation has been based on a single-loop automatic control system (ACS. It has been revealed that the less value of the relative time constant of an object leads to more integral control error in system with PID- regulator while operating external ACS perturbation. Decrease of numerical value of relative time constant of an object while operating external perturbation causes decrease of relative time concerning appearance of maximum dynamic control error from common relative control time.
Redmond, W H
2001-01-01
This chapter outlines current marketing practice from a managerial perspective. The role of marketing within an organization is discussed in relation to efficiency and adaptation to changing environments. Fundamental terms and concepts are presented in an applied context. The implementation of marketing plans is organized around the four P's of marketing: product (or service), promotion (including advertising), place of delivery, and pricing. These are the tools with which marketers seek to better serve their clients and form the basis for competing with other organizations. Basic concepts of strategic relationship management are outlined. Lastly, alternate viewpoints on the role of advertising in healthcare markets are examined.
Fine-structure constant constraints on Bekenstein-type models
Leal, P M M; Ventura, L B
2014-01-01
Astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant $\\alpha$, are an area of much increased recent activity, following some indications of possible spacetime variations at the few parts per million level. Here we obtain updated constraints on the Bekenstein-Sandvik-Barrow-Magueijo model, which is arguably the simplest model allowing for $\\alpha$ variations. Recent accurate spectroscopic measurements allow us to improve previous constraints by about an order of magnitude. We briefly comment on the dependence of the results on the data sample, as well as on the improvements expected from future facilities.
Pedro, A. A.; Arlievskii, M. P.
2009-12-01
Phosphorus and carbide furnaces are considered as an example to study the character of changes in and the nature of constant component U cc in the phase voltage of an ore-smelting furnace with a closed furnace top. The value and polarity of U cc depend on the relation between the chemical interaction of an electrode with the reaction-zone components and the degree of development and the conditions of an electric arc.
Villarreal, Susan M; Winokur, Olivia; Harrington, Laura
2017-09-01
Aedes aegypti (L.) males use female flight tone as a means of mate localization. By playing the sound of a flying female, males can be attracted to a trap to monitor mosquito populations and the progress of transgenic male releases. However, the female flight tone used to attract males needs to be optimized to maximize trap effectiveness. The fundamental frequency of female flight tone could be influenced by both body size and ambient temperature. However, no analysis yet has considered both the effect of body size and temperature on female flight tone of Ae. aegypti. Here, we present results for both these factors by recording the sounds of free-flying and tethered females across multiple temperature environments and with females reared for small, medium, and large body sizes. We demonstrate that female fundamental frequency is highly dependent on the environmental temperature, increasing ∼8-13 Hz with each °C gain. Body size and whether a female was tethered or free-flying did not impact the relationship between frequency and temperature, although further analysis is warranted. Our study highlights the importance of understanding the relationship between flight tone and temperature, and will inform the design of male mosquito traps. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.
Fundamentals of engineering electromagnetism
Energy Technology Data Exchange (ETDEWEB)
Kim, Nam; Yoon, Youngro; Jun, Sukhee; Jun, Hoin
2004-08-15
It indicates fundamentals of engineering electromagnetism. It mentions electromagnetic field model of introduction and International system of units and universal constant, Vector analysis with summary and orthogonal coordinate systems, electrostatic field on Coulomb's law and Gauss's law, electrostatic energy and strength, steady state current with Ohm's law and Joule's law and calculation of resistance, crystallite field with Vector's electrostatic potential, Biot-Savart law and application and Magnetic Dipole, time-Savart and Maxwell equation with potential function and Faraday law of electromagnetic induction, plane electromagnetic wave, transmission line, a wave guide and cavity resonator and antenna arrangement.
Fundamentals of semiconductor devices
Lindmayer, Joseph
1965-01-01
Semiconductor properties ; semiconductor junctions or diodes ; transistor fundamentals ; inhomogeneous impurity distributions, drift or graded-base transistors ; high-frequency properties of transistors ; band structure of semiconductors ; high current densities and mechanisms of carrier transport ; transistor transient response and recombination processes ; surfaces, field-effect transistors, and composite junctions ; additional semiconductor characteristics ; additional semiconductor devices and microcircuits ; more metal, insulator, and semiconductor combinations for devices ; four-pole parameters and configuration rotation ; four-poles of combined networks and devices ; equivalent circuits ; the error function and its properties ; Fermi-Dirac statistics ; useful physical constants.
Fundamental Physics and Precision Measurements
Hänsch, T. W.
2006-11-01
"Very high precision physics has always appealed to me. The steady improvement in technologies that afford higher and higher precision has been a regular source of excitement and challenge during my career. In science, as in most things, whenever one looks at something more closely, new aspects almost always come into play …" With these word from the book "How the Laser happened", Charles H. Townes expresses a passion for precision that is now shared by many scientists. Masers and lasers have become indispensible tools for precision measurements. During the past few years, the advent of femtosecond laser frequency comb synthesizers has revolutionized the art of directly comparing optical and microwave frequencies. Inspired by the needs of precision laser spectroscopy of the simple hydrogen atom, such frequency combs are now enabling ultra-precise spectroscopy over wide spectral ranges. Recent laboratory experiments are already setting stringent limits for possible slow variations of fundamental constants. Laser frequency combs also provide the long missing clockwork for optical atomic clocks that may ultimately reach a precision of parts in 1018 and beyond. Such tools will open intriguing new opportunities for fundamental experiments including new tests of special and general relativity. In the future, frequency comb techniques may be extended into the extreme ultraviolet and soft xray regime, opening a vast new spectral territory to precision measurements. Frequency combs have also become a key tool for the emerging new field of attosecond science, since they can control the electric field of ultrashort laser pulses on an unprecedented time scale. The biggest surprise in these endeavours would be if we found no surprise.
DEFF Research Database (Denmark)
Bouserhal, Rachel E.; MacDonald, Ewen; Falk, Tiago H.;
2016-01-01
concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise...... while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. Design: This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes...... in voice level and fundamental frequency in noise and with varying talker-to-listener distance. Study sample: Twelve participants with a mean age of 28 participated in this study. Results: Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded...
Wojnarowska, Z; Ngai, K L; Paluch, M
2014-12-01
The article reports the dependence of the conductivity relaxation on temperature T and pressure P in the canonical ionic glass former 0.4Ca(NO(3))(2)-0.6KNO(3)(CKN). At constant conductivity relaxation time τ(σ), the entire conductivity relaxation spectra obtained at widely different combinations of T and P superpose almost perfectly, and thus it is the ion-ion interaction but not thermodynamics that determines the frequency dispersion. Moreover, on vitrifying CKN by either elevating P or decreasing T, changes of P or T dependence of τ(σ) at the glass transition pressure P(g) and temperature T(g) are observed to occur at the same value, i.e., τ(σ)(P(g))=τ(σ)(T(g)), indicating that the relation between τ(σ) and the structural relaxation time τ(α) is also independent of P and T.
Mackenbach, Johan P; Kulhánová, Ivana; Bopp, Matthias; Deboosere, Patrick; Eikemo, Terje A; Hoffmann, Rasmus; Kulik, Margarete C; Leinsalu, Mall; Martikainen, Pekka; Menvielle, Gwenn; Regidor, Enrique; Wojtyniak, Bogdan; Östergren, Olof; Lundberg, Olle
2015-02-01
Link and Phelan have proposed to explain the persistence of health inequalities from the fact that socioeconomic status is a "fundamental cause" which embodies an array of resources that can be used to avoid disease risks no matter what mechanisms are relevant at any given time. To test this theory we compared the magnitude of inequalities in mortality between more and less preventable causes of death in 19 European populations, and assessed whether inequalities in mortality from preventable causes are larger in countries with larger resource inequalities. We collected and harmonized mortality data by educational level on 19 national and regional populations from 16 European countries in the first decade of the 21st century. We calculated age-adjusted Relative Risks of mortality among men and women aged 30-79 for 24 causes of death, which were classified into four groups: amenable to behavior change, amenable to medical intervention, amenable to injury prevention, and non-preventable. Although an overwhelming majority of Relative Risks indicate higher mortality risks among the lower educated, the strength of the education-mortality relation is highly variable between causes of death and populations. Inequalities in mortality are generally larger for causes amenable to behavior change, medical intervention and injury prevention than for non-preventable causes. The contrast between preventable and non-preventable causes is large for causes amenable to behavior change, but absent for causes amenable to injury prevention among women. The contrast between preventable and non-preventable causes is larger in Central & Eastern Europe, where resource inequalities are substantial, than in the Nordic countries and continental Europe, where resource inequalities are relatively small, but they are absent or small in Southern Europe, where resource inequalities are also large. In conclusion, our results provide some further support for the theory of "fundamental causes". However
Fundamental stellar parameters
Wittkowski, M
2004-01-01
I present a discussion of fundamental stellar parameters and their observational determination in the context of interferometric measurements with current and future optical/infrared interferometric facilities. Stellar parameters and the importance of their determination for stellar physics are discussed. One of the primary uses of interferometry in the field of stellar physics is the measurement of the intensity profile across the stellar disk, both as a function of position angle and of wavelength. High-precision fundamental stellar parameters are also derived by characterizations of binary and multiple system using interferometric observations. This topic is discussed in detail elsewhere in these proceedings. Comparison of observed spectrally dispersed center-to-limb intensity variations with models of stellar atmospheres and stellar evolution may result in an improved understanding of key phenomena in stellar astrophysics such as the precise evolutionary effects on the main sequence, the evolution of meta...
Bouserhal, Rachel E; Macdonald, Ewen N; Falk, Tiago H; Voix, Jérémie
2016-01-01
Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes in voice level and fundamental frequency in noise and with varying talker-to-listener distance. Twelve participants with a mean age of 28 participated in this study. Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded quiet condition. This implies that a model can be developed to better understand speech production for the occluded ear.
Fundamental units: physics and metrology
Okun, Lev Borisovich
2003-01-01
The problem of fundamental units is discussed in the context of achievements of both theoretical physics and modern metrology. On one hand, due to fascinating accuracy of atomic clocks, the traditional macroscopic standards of metrology (second, metre, kilogram) are giving way to standards based on fundamental units of nature: velocity of light $c$ and quantum of action $h$. On the other hand, the poor precision of gravitational constant $G$, which is widely believed to define the ``cube of theories'' and the units of the future ``theory of everything'', does not allow to use $G$ as a fundamental dimensional constant in metrology. The electromagnetic units in SI are actually based on concepts of prerelativistic classical electrodynamics such as ether, electric permitivity and magnetic permeability of vacuum. Concluding remarks are devoted to terminological confusion which accompanies the progress in basic physics and metrology.
Decay constants in geochronology
Institute of Scientific and Technical Information of China (English)
IgorM.Villa; PaulR.Renne
2005-01-01
Geologic time is fundamental to the Earth Sciences, and progress in many disciplines depends critically on our ability to measure time with increasing accuracy and precision. Isotopic geochronology makes use of the decay of radioactive nuclides as a help to quantify the histories of rock, minerals, and other materials. Both accuracy and precision of radioisotopic ages are, at present, limited by those of radioactive decay constants. Modem mass spectrometers can measure isotope ratios with a precision of 10-4 or better. On the other hand, the uncertainties associated with direct half-life determinations are, in most cases, still at the percent level. The present short note briefly summarizes progress and problems that have been encountered during the Working Group's activity.
Tenti, Lorenzo; Maynau, Daniel; Angeli, Celestino; Calzado, Carmen J
2016-07-21
A new strategy based on orthogonal valence-bond analysis of the wave function combined with intermediate Hamiltonian theory has been applied to the evaluation of the magnetic coupling constants in two AF systems. This approach provides both a quantitative estimate of the J value and a detailed analysis of the main physical mechanisms controlling the coupling, using a combined perturbative + variational scheme. The procedure requires a selection of the dominant excitations to be treated variationally. Two methods have been employed: a brute-force selection, using a logic similar to that of the CIPSI approach, or entanglement measures, which identify the most interacting orbitals in the system. Once a reduced set of excitations (about 300 determinants) is established, the interaction matrix is dressed at the second-order of perturbation by the remaining excitations of the CI space. The diagonalization of the dressed matrix provides J values in good agreement with experimental ones, at a very low-cost. This approach demonstrates the key role of d → d* excitations in the quantitative description of the magnetic coupling, as well as the importance of using an extended active space, including the bridging ligand orbitals, for the binuclear model of the intermediates of multicopper oxidases. The method is a promising tool for dealing with complex systems containing several active centers, as an alternative to both pure variational and DFT approaches.
Varying constants, Gravitation and Cosmology
Uzan, Jean-Philippe
2010-01-01
Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describ...
Cardone, V F; Diaferio, A; Tortora, C; Molinaro, R
2010-01-01
Modified Newtonian Dynamics (MOND) has been shown to be able to fit spiral galaxy rotation curves as well as giving a theoretical foundation for empirically determined scaling relations, such as the Tully - Fisher law, without the need for a dark matter halo. As a complementary analysis, one should investigate whether MOND can also reproduce the dynamics of early - type galaxies (ETGs) without dark matter. As a first step, we here show that MOND can indeed fit the observed central velocity dispersion $\\sigma_0$ of a large sample of ETGs assuming a simple MOND interpolating functions and constant anisotropy. We also show that, under some assumptions on the luminosity dependence of the Sersic n parameter and the stellar M/L ratio, MOND predicts a fundamental plane for ETGs : a log - linear relation among the effective radius $R_{eff}$, $\\sigma_0$ and the mean effective intensity $\\langle I_e \\rangle$. However, we predict a tilt between the observed and the MOND fundamental planes.
Constant Proportion Portfolio Insurance
DEFF Research Database (Denmark)
Jessen, Cathrine
2014-01-01
Portfolio insurance, as practiced in 1987, consisted of trading between an underlying stock portfolio and cash, using option theory to place a floor on the value of the position, as if it included a protective put. Constant Proportion Portfolio Insurance (CPPI) is an option-free variation...... on the theme, originally proposed by Fischer Black. In CPPI, a financial institution guarantees a floor value for the “insured” portfolio and adjusts the stock/bond mix to produce a leveraged exposure to the risky assets, which depends on how far the portfolio value is above the floor. Plain-vanilla portfolio...... insurance largely died with the crash of 1987, but CPPI is still going strong. In the frictionless markets of finance theory, the issuer’s strategy to hedge its liability under the contract is clear, but in the real world with transactions costs and stochastic jump risk, the optimal strategy is less obvious...
Energy Technology Data Exchange (ETDEWEB)
Marion, H
2005-03-15
We developed a method of measurement of the frequency shift due to the collisions between cold atoms. This is the main systematic limitation for the accuracy of the Cs{sup 133} based fountains ({approx} 10{sup -15} in relative frequency). Consequently, we can measure this effect near 0.5% This opens prospects for improvements of the fountains performances in term of accuracy until 10{sup -16}. The fountain has also obtained a stability about 10{sup -14} at 1 s. We discovered for the first time, at very low magnetic field (5 {+-} 1 mG), Feshbach resonances. We also took a new absolute measurement of the hyperfine transition of the Rb{sup 87}, which is the most precise ever carried out and is used now as definition for the secondary standard. By comparing this value with those measured the previous years, we could carry out a test of the stability of the fine structure constant on the level of 10{sup -15} /yr. We led local comparisons between atomic fountains and the other fountains of the laboratory. Most stable it is unrolled with a combined stability of 5.10{sup -14} at 1 s. The behavior of the difference of the two clocks goes like white frequency noise up to 3.10{sup -16}. The assessment of the dual fountain accuracy budget has been evaluated at 7.10{sup -16} for the cesium part and 8.10{sup -16} for the rubidium part. We contributed to the realization of the scale of International Atomic Time, by series of calibrations of hydrogen masers. An atomic comparison of fountain by satellite links was tested between our laboratory and our German counterpart. This measurement has determined the good agreement between the two clocks. (author)
Meana-Pañeda, Rubén; Truhlar, Donald G; Fernández-Ramos, Antonio
2011-03-07
We report a detailed theoretical study of the hydrogen abstraction reaction from methanol by atomic hydrogen. The study includes the analysis of thermal rate constants, branching ratios, and kinetic isotope effects. Specifically, we have performed high-level computations at the MC3BB level together with direct dynamics calculations by canonical variational transition state theory (CVT) with the microcanonically optimized multidimensional tunneling (μOMT) transmission coefficient (CVT/μOMT) to study both the CH(3)OH+H→CH(2)OH+H(2) (R1) reaction and the CH(3)OH+H→CH(3)O+H(2) (R2) reaction. The CVT/μOMT calculations show that reaction R1 dominates in the whole range 298≤T (K)≤2500 and that anharmonic effects on the torsional mode about the C-O bond are important, mainly at high temperatures. The activation energy for the total reaction sum of R1 and R2 reactions changes substantially with temperature and, therefore, the use of straight-line Arrhenius plots is not valid. We recommend the use of new expressions for the total R1 + R2 reaction and for the R1 and R2 individual reactions.
String theory, cosmology and varying constants
Damour, Thibault
In string theory the coupling `constants' appearing in the low-energy effective Lagrangian are determined by the vacuum expectation values of some (a priori) massless scalar fields (dilaton, moduli). This naturally leads one to expect a correlated variation of all the coupling constants, and an associated violation of the equivalence principle. We review some string-inspired theoretical models which incorporate such a spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo; Rhenium decay) and with present equivalence principle tests. Barring a very unnatural fine-tuning of parameters, a variation of the fine-structure constant as large as that recently `observed' by Webb et al. in quasar absorption spectra appears to be incompatible with these phenomenological constraints. Independently of any model, it is emphasized that the best experimental probe of varying constants are high-precision tests of the universality of free fall, such as MICROSCOPE and STEP.
String theory, cosmology and varying constants
Damour, Thibault Marie Alban Guillaume
2002-01-01
In string theory the coupling ``constants'' appearing in the low-energy effective Lagrangian are determined by the vacuum expectation values of some (a priori) massless scalar fields (dilaton, moduli). This naturally leads one to expect a correlated variation of all the coupling constants, and an associated violation of the equivalence principle. We review some string-inspired theoretical models which incorporate such a spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo; Rhenium decay) and with present equivalence principle tests. Barring a very unnatural fine-tuning of parameters, a variation of the fine-structure constant as large as that recently ``observed'' by Webb et al. in quasar absorption spectra appears to be incompatible with these phenomenological constraints. Independently of any model, it is emphasized that the best experimental probe of varying constants are high-precision tests of the universa...
Exchange Rates and Fundamentals.
Engel, Charles; West, Kenneth D.
2005-01-01
We show analytically that in a rational expectations present-value model, an asset price manifests near-random walk behavior if fundamentals are I (1) and the factor for discounting future fundamentals is near one. We argue that this result helps explain the well-known puzzle that fundamental variables such as relative money supplies, outputs,…
Why isn't the solar constant a constant?
Li, K J; Xu, J C; Gao, P X; Yang, L H; Liang, H F; Zhan, L S
2012-01-01
In order to probe the mechanism of variations of the Solar Constant on the inter-solar-cycle scale, total solar irradiance (TSI, the so-called Solar Constant) in the time interval of 7 November 1978 to 20 September 2010 is decomposed into three components through the empirical mode decomposition and time-frequency analyses. The first component is the rotation signal, counting up to 42.31% of the total variation of TSI, which is understood to be mainly caused by large magnetic structures, including sunspot groups. The second is an annual-variation signal, counting up to 15.17% of the total variation, the origin of which is not known at this point in time. Finally, the third is the inter-solar-cycle signal, counting up to 42.52%, which are inferred to be caused by the network magnetic elements in quiet regions, whose magnetic flux ranges from $(4.27-38.01)\\times10^{19}$ Mx.
On a time varying fine structure constant
Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.
2001-01-01
By employing Dirac LNH, and a further generalization by Berman (GLNH), we estimate how should vary the total number of nucleons, the energy density, Newton Gravitational constant, the cosmological constant, the magnetic permeability and electric permitivity, of the Universe,in order to account for the experimentally observed time variation of the fine structure constant. As a bonus,we find an acceptable value for the deceleration parameter of the present Universe, compatible with the Supernovae observations.
Determination of the gravitational constant G
Institute of Scientific and Technical Information of China (English)
HU Zhong-kun; LIU Qi; LUO Jun
2006-01-01
A precise knowledge of the Newtonian gravitational constant G has an important role in physics and is of considerable meteorological interest.Although G was the first physical constant to be introduced and measured in the history of science,it is still the least precisely determined of all the fundamental constants of nature.The 2002 CODATA recommended value for G,G=(6.6742±0.0010)×10-11m3·kg-1·s-2,has an uncertainty of 150 parts per million (ppm),much larger than that of all other fundamental constants.Reviewed here is the status of our knowledge of the absolute value of G,methods for determining G,and recent high precision experiments for determining G.
Ion exchange equilibrium constants
Marcus, Y
2013-01-01
Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and
Some comments on the universal constant in DSR
Girelli, F; Girelli, Florian; Livine, Etera R.
2006-01-01
Deformed Special Relativity is usually presented as a deformation of Special Relativity accommodating a new universal constant, the Planck mass, while respecting the relativity principle. In order to avoid some fundamental problems (e.g. soccer ball problem), we argue that we should switch point of view and consider instead the Newton constant $G$ as the universal constant.
Cosmological Constant, Fine Structure Constant and Beyond
Wei, Hao; Li, Hong-Yu; Xue, Dong-Ze
2016-01-01
In this work, we consider the cosmological constant model $\\Lambda\\propto\\alpha^{-6}$, which is well motivated from three independent approaches. As is well known, the evidence of varying fine structure constant $\\alpha$ was found in 1998. If $\\Lambda\\propto\\alpha^{-6}$ is right, it means that the cosmological constant $\\Lambda$ should be also varying. In this work, we try to develop a suitable framework to model this varying cosmological constant $\\Lambda\\propto\\alpha^{-6}$, in which we view it from an interacting vacuum energy perspective. We propose two types of models to describe the evolutions of $\\Lambda$ and $\\alpha$. Then, we consider the observational constraints on these models, by using the 293 $\\Delta\\alpha/\\alpha$ data from the absorption systems in the spectra of distant quasars, and the data of type Ia supernovae (SNIa), cosmic microwave background (CMB), baryon acoustic oscillation (BAO). We find that the model parameters can be tightly constrained to the narrow ranges of ${\\cal O}(10^{-5})$ t...
Babu, V
2014-01-01
Fundamentals of Gas Dynamics, Second Edition isa comprehensively updated new edition and now includes a chapter on the gas dynamics of steam. It covers the fundamental concepts and governing equations of different flows, and includes end of chapter exercises based on the practical applications. A number of useful tables on the thermodynamic properties of steam are also included.Fundamentals of Gas Dynamics, Second Edition begins with an introduction to compressible and incompressible flows before covering the fundamentals of one dimensional flows and normal shock wav
Ramachandran, V.; Halfpenny, PJ; Roberts, KJ
2017-01-01
The fundamentals of crystal science notably crystallography, crystal chemistry, crystal defects, crystal morphology and the surface chemistry of crystals are introduced with particular emphasis on organic crystals.
The Determination of the Strong Coupling Constant
Dissertori, Günther
2016-10-01
The strong coupling constant is one of the fundamental parameters of the Standard Theory of particle physics. In this review I will briefly summarise the theoretical framework, within which the strong coupling constant is defined and how it is connected to measurable observables. Then I will give an historical overview of its experimental determinations and discuss the current status and world average value. Among the many different techniques used to determine this coupling constant in the context of quantum chromodynamics, I will focus in particular on a number of measurements carried out at the Large Electron-Positron Collider (LEP) and the Large Hadron Collider (LHC) at CERN.
Halliday, David; Resnick, Robert; Walker, Jearl
2003-01-01
No other book on the market today can match the success of Halliday, Resnick and Walker's Fundamentals of Physics! In a breezy, easy-to-understand style the book offers a solid understanding of fundamental physics concepts, and helps readers apply this conceptual understanding to quantitative problem solving.
Directory of Open Access Journals (Sweden)
Justin Zylstra
2014-12-01
Full Text Available I argue that dependence is neither necessary nor sufficient for relative fundamentality. I then introduce the notion of 'likeness in nature' and provide an account of relative fundamentality in terms of it and the notion of dependence. Finally, I discuss some puzzles that arise in Aristotle's Categories, to which the theory developed is applied.
Generalized Pickands constants
Debicki, K.G.
2001-01-01
Pickands constants play an important role in the exact asymptotic of extreme values for Gaussian stochastic processes. By the {it generalized Pickands constant ${cal H_{eta$ we mean the limit begin{eqnarray* {cal H_{eta= lim_{T to inftyfrac{ {cal H_{eta(T){T, end{eqnarray* where ${cal H_{eta(T)= Exp
Schubert, Thomas F
2015-01-01
This book, Electronic Devices and Circuit Application, is the first of four books of a larger work, Fundamentals of Electronics. It is comprised of four chapters describing the basic operation of each of the four fundamental building blocks of modern electronics: operational amplifiers, semiconductor diodes, bipolar junction transistors, and field effect transistors. Attention is focused on the reader obtaining a clear understanding of each of the devices when it is operated in equilibrium. Ideas fundamental to the study of electronic circuits are also developed in the book at a basic level to
Dereli, Tekin; Yetişmişoǧlu, Cem
2016-09-01
We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti-de Sitter space AdS3) and constant torsion provide exact solutions.
Dereli, T
2016-01-01
We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space $AdS_3$) and constant torsion provide exact solutions.
Fundamentals of electrochemical science
Oldham, Keith
1993-01-01
Key Features* Deals comprehensively with the basic science of electrochemistry* Treats electrochemistry as a discipline in its own right and not as a branch of physical or analytical chemistry* Provides a thorough and quantitative description of electrochemical fundamentals
Fundamentals of crystallography
2011-01-01
Crystallography is a basic tool for scientists in many diverse disciplines. This text offers a clear description of fundamentals and of modern applications. It supports curricula in crystallography at undergraduate level.
Fundamentals of structural dynamics
Craig, Roy R
2006-01-01
From theory and fundamentals to the latest advances in computational and experimental modal analysis, this is the definitive, updated reference on structural dynamics.This edition updates Professor Craig's classic introduction to structural dynamics, which has been an invaluable resource for practicing engineers and a textbook for undergraduate and graduate courses in vibrations and/or structural dynamics. Along with comprehensive coverage of structural dynamics fundamentals, finite-element-based computational methods, and dynamic testing methods, this Second Edition includes new and e
Masses of Fundamental Particles
Terazawa, Hidezumi
2011-01-01
Not only the masses of fundamental particles including the weak bosons, Higgs scalar, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos are all explained and/or predicted in the unified composite model of quarks and leptons successfully. In addition, both of the two anomalies recently found by the CDF Collaboration are suggested to be taken as evidences for the substructure of the fundamental particles.
Information security fundamentals
Peltier, Thomas R
2013-01-01
Developing an information security program that adheres to the principle of security as a business enabler must be the first step in an enterprise's effort to build an effective security program. Following in the footsteps of its bestselling predecessor, Information Security Fundamentals, Second Edition provides information security professionals with a clear understanding of the fundamentals of security required to address the range of issues they will experience in the field.The book examines the elements of computer security, employee roles and r
The time constant of the somatogravic illusion.
Correia Grácio, B J; de Winkel, K N; Groen, E L; Wentink, M; Bos, J E
2013-02-01
Without visual feedback, humans perceive tilt when experiencing a sustained linear acceleration. This tilt illusion is commonly referred to as the somatogravic illusion. Although the physiological basis of the illusion seems to be well understood, the dynamic behavior is still subject to discussion. In this study, the dynamic behavior of the illusion was measured experimentally for three motion profiles with different frequency content. Subjects were exposed to pure centripetal accelerations in the lateral direction and were asked to indicate their tilt percept by means of a joystick. Variable-radius centrifugation during constant angular rotation was used to generate these motion profiles. Two self-motion perception models were fitted to the experimental data and were used to obtain the time constant of the somatogravic illusion. Results showed that the time constant of the somatogravic illusion was on the order of two seconds, in contrast to the higher time constant found in fixed-radius centrifugation studies. Furthermore, the time constant was significantly affected by the frequency content of the motion profiles. Motion profiles with higher frequency content revealed shorter time constants which cannot be explained by self-motion perception models that assume a fixed time constant. Therefore, these models need to be improved with a mechanism that deals with this variable time constant. Apart from the fundamental importance, these results also have practical consequences for the simulation of sustained accelerations in motion simulators.
Astronomical reach of fundamental physics
Burrows, Adam S.; Ostriker, Jeremiah P.
2014-02-01
Using basic physical arguments, we derive by dimensional and physical analysis the characteristic masses and sizes of important objects in the universe in terms of just a few fundamental constants. This exercise illustrates the unifying power of physics and the profound connections between the small and the large in the cosmos we inhabit. We focus on the minimum and maximum masses of normal stars, the corresponding quantities for neutron stars, the maximum mass of a rocky planet, the maximum mass of a white dwarf, and the mass of a typical galaxy. To zeroth order, we show that all these masses can be expressed in terms of either the Planck mass or the Chandrasekar mass, in combination with various dimensionless quantities. With these examples, we expose the deep interrelationships imposed by nature between disparate realms of the universe and the amazing consequences of the unifying character of physical law.
Materials Fundamentals of Gate Dielectrics
Demkov, Alexander A
2006-01-01
This book presents materials fundamentals of novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scalling of the CMOS devices. This is a very fast evolving field of research so we choose to focus on the basic understanding of the structure, thermodunamics, and electronic properties of these materials that determine their performance in device applications. Most of these materials are transition metal oxides. Ironically, the d-orbitals responsible for the high dielectric constant cause sever integration difficulties thus intrinsically limiting high-k dielectrics. Though new in the electronics industry many of these materials are wel known in the field of ceramics, and we describe this unique connection. The complexity of the structure-property relations in TM oxides makes the use of the state of the art first-principles calculations necessary. Several chapters give a detailed description of the modern theory of polarization, and heterojunction band discont...
Astronomical reach of fundamental physics.
Burrows, Adam S; Ostriker, Jeremiah P
2014-02-18
Using basic physical arguments, we derive by dimensional and physical analysis the characteristic masses and sizes of important objects in the universe in terms of just a few fundamental constants. This exercise illustrates the unifying power of physics and the profound connections between the small and the large in the cosmos we inhabit. We focus on the minimum and maximum masses of normal stars, the corresponding quantities for neutron stars, the maximum mass of a rocky planet, the maximum mass of a white dwarf, and the mass of a typical galaxy. To zeroth order, we show that all these masses can be expressed in terms of either the Planck mass or the Chandrasekar mass, in combination with various dimensionless quantities. With these examples, we expose the deep interrelationships imposed by nature between disparate realms of the universe and the amazing consequences of the unifying character of physical law.
Fundamentals of algebraic topology
Weintraub, Steven H
2014-01-01
This rapid and concise presentation of the essential ideas and results of algebraic topology follows the axiomatic foundations pioneered by Eilenberg and Steenrod. The approach of the book is pragmatic: while most proofs are given, those that are particularly long or technical are omitted, and results are stated in a form that emphasizes practical use over maximal generality. Moreover, to better reveal the logical structure of the subject, the separate roles of algebra and topology are illuminated. Assuming a background in point-set topology, Fundamentals of Algebraic Topology covers the canon of a first-year graduate course in algebraic topology: the fundamental group and covering spaces, homology and cohomology, CW complexes and manifolds, and a short introduction to homotopy theory. Readers wishing to deepen their knowledge of algebraic topology beyond the fundamentals are guided by a short but carefully annotated bibliography.
Dick, Erik
2015-01-01
This book explores the working principles of all kinds of turbomachines. The same theoretical framework is used to analyse the different machine types. Fundamentals are first presented and theoretical concepts are then elaborated for particular machine types, starting with the simplest ones.For each machine type, the author strikes a balance between building basic understanding and exploring knowledge of practical aspects. Readers are invited through challenging exercises to consider how the theory applies to particular cases and how it can be generalised. The book is primarily meant as a course book. It teaches fundamentals and explores applications. It will appeal to senior undergraduate and graduate students in mechanical engineering and to professional engineers seeking to understand the operation of turbomachines. Readers will gain a fundamental understanding of turbomachines. They will also be able to make a reasoned choice of turbomachine for a particular application and to understand its operation...
Energy Technology Data Exchange (ETDEWEB)
Brown, F.B.; Sutton, T.M.
1996-02-01
This report is composed of the lecture notes from the first half of a 32-hour graduate-level course on Monte Carlo methods offered at KAPL. These notes, prepared by two of the principle developers of KAPL`s RACER Monte Carlo code, cover the fundamental theory, concepts, and practices for Monte Carlo analysis. In particular, a thorough grounding in the basic fundamentals of Monte Carlo methods is presented, including random number generation, random sampling, the Monte Carlo approach to solving transport problems, computational geometry, collision physics, tallies, and eigenvalue calculations. Furthermore, modern computational algorithms for vector and parallel approaches to Monte Carlo calculations are covered in detail, including fundamental parallel and vector concepts, the event-based algorithm, master/slave schemes, parallel scaling laws, and portability issues.
Fundamentals of fluid lubrication
Hamrock, Bernard J.
1991-01-01
The aim is to coordinate the topics of design, engineering dynamics, and fluid dynamics in order to aid researchers in the area of fluid film lubrication. The lubrication principles that are covered can serve as a basis for the engineering design of machine elements. The fundamentals of fluid film lubrication are presented clearly so that students that use the book will have confidence in their ability to apply these principles to a wide range of lubrication situations. Some guidance on applying these fundamentals to the solution of engineering problems is also provided.
Infosec management fundamentals
Dalziel, Henry
2015-01-01
Infosec Management Fundamentals is a concise overview of the Information Security management concepts and techniques, providing a foundational template for both experienced professionals and those new to the industry. This brief volume will also appeal to business executives and managers outside of infosec who want to understand the fundamental concepts of Information Security and how it impacts their business decisions and daily activities. Teaches ISO/IEC 27000 best practices on information security management Discusses risks and controls within the context of an overall information securi
Smith, Peter
2013-01-01
Written for the piping engineer and designer in the field, this two-part series helps to fill a void in piping literature,since the Rip Weaver books of the '90s were taken out of print at the advent of the Computer Aid Design(CAD) era. Technology may have changed, however the fundamentals of piping rules still apply in the digitalrepresentation of process piping systems. The Fundamentals of Piping Design is an introduction to the designof piping systems, various processes and the layout of pipe work connecting the major items of equipment forthe new hire, the engineering student and the vetera
Homeschooling and religious fundamentalism
Directory of Open Access Journals (Sweden)
Robert KUNZMAN
2010-10-01
Full Text Available This article considers the relationship between homeschooling and religious fundamentalism by focusing on their intersection in the philosophies and practices of conservative Christian homeschoolers in the United States. Homeschooling provides an ideal educational setting to support several core fundamentalist principles: resistance to contemporary culture; suspicion of institutional authority and professional expertise; parental control and centrality of the family; and interweaving of faith and academics. It is important to recognize, however, that fundamentalism exists on a continuum; conservative religious homeschoolers resist liberal democratic values to varying degrees, and efforts to foster dialogue and accommodation with religious homeschoolers can ultimately helpstrengthen the broader civic fabric.
Pragmatic electrical engineering fundamentals
Eccles, William
2011-01-01
Pragmatic Electrical Engineering: Fundamentals introduces the fundamentals of the energy-delivery part of electrical systems. It begins with a study of basic electrical circuits and then focuses on electrical power. Three-phase power systems, transformers, induction motors, and magnetics are the major topics.All of the material in the text is illustrated with completely-worked examples to guide the student to a better understanding of the topics. This short lecture book will be of use at any level of engineering, not just electrical. Its goal is to provide the practicing engineer with a practi
Fundamentals of nonlinear optics
Powers, Peter E
2011-01-01
Peter Powers's rigorous but simple description of a difficult field keeps the reader's attention throughout. … All chapters contain a list of references and large numbers of practice examples to be worked through. … By carefully working through the proposed problems, students will develop a sound understanding of the fundamental principles and applications. … the book serves perfectly for an introductory-level course for second- and third-order nonlinear optical phenomena. The author's writing style is refreshing and original. I expect that Fundamentals of Nonlinear Optics will fast become pop
Fundamentals of continuum mechanics
Rudnicki, John W
2014-01-01
A concise introductory course text on continuum mechanics Fundamentals of Continuum Mechanics focuses on the fundamentals of the subject and provides the background for formulation of numerical methods for large deformations and a wide range of material behaviours. It aims to provide the foundations for further study, not just of these subjects, but also the formulations for much more complex material behaviour and their implementation computationally. This book is divided into 5 parts, covering mathematical preliminaries, stress, motion and deformation, balance of mass, momentum and energ
Antennas fundamentals, design, measurement
Long, Maurice
2009-01-01
This comprehensive revision (3rd Edition) is a senior undergraduate or first-year graduate level textbook on antenna fundamentals, design, performance analysis, and measurements. In addition to its use as a formal course textbook, the book's pragmatic style and emphasis on the fundamentals make it especially useful to engineering professionals who need to grasp the essence of the subject quickly but without being mired in unnecessary detail. This new edition was prepared for a first year graduate course at Southern Polytechnic State University in Georgia. It provides broad coverage of antenna
Reis, Mario
2013-01-01
The Fundamentals of Magnetism is a truly unique reference text, that explores the study of magnetism and magnetic behavior with a depth that no other book can provide. It covers the most detailed descriptions of the fundamentals of magnetism providing an emphasis on statistical mechanics which is absolutely critical for understanding magnetic behavior. The books covers the classical areas of basic magnetism, including Landau Theory and magnetic interactions, but features a more concise and easy-to-read style. Perfect for upper-level graduate students and industry researchers, The Fu
Peselnick, L.; Robie, R.A.
1962-01-01
The recent measurements of the elastic constants of calcite by Reddy and Subrahmanyam (1960) disagree with the values obtained independently by Voigt (1910) and Bhimasenachar (1945). The present authors, using an ultrasonic pulse technique at 3 Mc and 25??C, determined the elastic constants of calcite using the exact equations governing the wave velocities in the single crystal. The results are C11=13.7, C33=8.11, C44=3.50, C12=4.82, C13=5.68, and C14=-2.00, in units of 1011 dyncm2. Independent checks of several of the elastic constants were made employing other directions and polarizations of the wave velocities. With the exception of C13, these values substantially agree with the data of Voigt and Bhimasenachar. ?? 1962 The American Institute of Physics.
Implications of a Time-Varying Fine Structure Constant
Alfonso-Faus, A
2002-01-01
Much work has been done after the possibility of a fine structure constant being time-varying. It has been taken as an indication of a time-varying speed of light. Here we prove that this is not the case. We prove that the speed of light may or may not vary with time, independently of the fine structure constant being constant or not. Time variations of the speed of light, if present, have to be derived by some other means and not from the fine structure constant. No implications based on the possible variations of the fine structure constant can be imposed on the speed of light.
Algorithm for structure constants
Paiva, F M
2011-01-01
In a $n$-dimensional Lie algebra, random numerical values are assigned by computer to $n(n-1)$ especially selected structure constants. An algorithm is then created, which calculates without ambiguity the remaining constants, obeying the Jacobi conditions. Differently from others, this algorithm is suitable even for poor personal computer. ------------- En $n$-dimensia algebro de Lie, hazardaj numeraj valoroj estas asignitaj per komputilo al $n(n-1)$ speciale elektitaj konstantoj de strukturo. Tiam algoritmo estas kreita, kalkulante senambigue la ceterajn konstantojn, obeante kondicxojn de Jacobi. Malsimile al aliaj algoritmoj, tiu cxi tauxgas ecx por malpotenca komputilo.
Radiographic constant exposure technique
DEFF Research Database (Denmark)
Domanus, Joseph Czeslaw
1985-01-01
The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographic image quality...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...
Bosma, Wieb
2009-01-01
The average value of log s(n)/n taken over the first N even integers is shown to converge to a constant lambda when N tends to infinity; moreover, the value of this constant is approximated and proven to be less than 0. Here s(n) sums the divisors of n less than n. Thus the geometric mean of s(n)/n, the growth factor of the function s, in the long run tends to be less than 1. This could be interpreted as probabilistic evidence that aliquot sequences tend to remain bounded.
Homeschooling and Religious Fundamentalism
Kunzman, Robert
2010-01-01
This article considers the relationship between homeschooling and religious fundamentalism by focusing on their intersection in the philosophies and practices of conservative Christian homeschoolers in the United States. Homeschooling provides an ideal educational setting to support several core fundamentalist principles: resistance to…
Fundamental partial compositeness
DEFF Research Database (Denmark)
Sannino, Francesco; Strumia, Alessandro; Tesi, Andrea
2016-01-01
We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model fermions realize the partial compositeness scenario. Unde...
Fundamentals of Business Economics
2013-01-01
Powerpoint presentations of the 9 theoretical units of the subject: Fundamentals of Business Economics. Business Administration Degree. Faculty of Economics. University of Alicante En el marco de ayudas a preparación de materiales docentes en lengua inglesa, por parte del Servei de Política Llingüística de la Universidad de Alicante
Fundamental Physics Microgravity Sensitivity
Israelsson, Ulf
1998-01-01
An introduction followed by a brief discussion about the sensitivity to microgravity environment disturbances for some recent and planned experiments in microgravity fundamental physics will be presented. In particular, correlation between gravity disturbances and the quality of science data sets measured by the Confined Helium Experiment (CHEX) during ground testing and during the November 1997 USMP-4 flight will be described.
Fundamental Metallurgy of Solidification
DEFF Research Database (Denmark)
Tiedje, Niels
2004-01-01
The text takes the reader through some fundamental aspects of solidification, with focus on understanding the basic physics that govern solidification in casting and welding. It is described how the first solid is formed and which factors affect nucleation. It is described how crystals grow from ...
Fundamentals of convolutional coding
Johannesson, Rolf
2015-01-01
Fundamentals of Convolutional Coding, Second Edition, regarded as a bible of convolutional coding brings you a clear and comprehensive discussion of the basic principles of this field * Two new chapters on low-density parity-check (LDPC) convolutional codes and iterative coding * Viterbi, BCJR, BEAST, list, and sequential decoding of convolutional codes * Distance properties of convolutional codes * Includes a downloadable solutions manual
This study guide provides comments and references for professional soil scientists who are studying for the soil science fundamentals exam needed as the first step for certification. The performance objectives were determined by the Soil Science Society of America's Council of Soil Science Examiners...
Fundamentals and Optimal Institutions
DEFF Research Database (Denmark)
Gonzalez-Eiras, Martin; Harmon, Nikolaj Arpe; Rossi, Martín
2016-01-01
of regulatory institutions such as revenue sharing, salary caps or luxury taxes. We show, theoretically and empirically, that these large differences in adopted institutions can be rationalized as optimal responses to differences in the fundamental characteristics of the sports being played. This provides...
Wakker, K.F.
2015-01-01
This book deals with the motion of the center of mass of a spacecraft; this discipline is generally called astrodynamics. The book focuses on an analytical treatment of the motion of spacecraft and provides insight into the fundamentals of spacecraft orbit dynamics. A large number of topics are trea
Fundamentals of plasma physics
Bittencourt, J A
1986-01-01
A general introduction designed to present a comprehensive, logical and unified treatment of the fundamentals of plasma physics based on statistical kinetic theory. Its clarity and completeness make it suitable for self-learning and self-paced courses. Problems are included.
Measuring Boltzmann's Constant with Carbon Dioxide
Ivanov, Dragia; Nikolov, Stefan
2013-01-01
In this paper we present two experiments to measure Boltzmann's constant--one of the fundamental constants of modern-day physics, which lies at the base of statistical mechanics and thermodynamics. The experiments use very basic theory, simple equipment and cheap and safe materials yet provide very precise results. They are very easy and…
Measuring Boltzmann's Constant with Carbon Dioxide
Ivanov, Dragia; Nikolov, Stefan
2013-01-01
In this paper we present two experiments to measure Boltzmann's constant--one of the fundamental constants of modern-day physics, which lies at the base of statistical mechanics and thermodynamics. The experiments use very basic theory, simple equipment and cheap and safe materials yet provide very precise results. They are very easy and…
Polyhedral Scattering of Fundamental Monopoles
Battye, R; Rychenkova, P; Sutcliffe, P; Battye, Richard; Gibbons, Gary; Rychenkova, Paulina; Sutcliffe, Paul
2003-01-01
The dynamics of n slowly moving fundamental monopoles in the SU(n+1) BPS Yang-Mills-Higgs theory can be approximated by geodesic motion on the 4n-dimensional hyperkahler Lee-Weinberg-Yi manifold. In this paper we apply a variational method to construct some scaling geodesics on this manifold. These geodesics describe the scattering of n monopoles which lie on the vertices of a bouncing polyhedron; the polyhedron contracts from infinity to a point, representing the spherically symmetric n-monopole, and then expands back out to infinity. For different monopole masses the solutions generalize to form bouncing nested polyhedra. The relevance of these results to the dynamics of well separated SU(2) monopoles is also discussed.
Scott, Tricia
2015-11-01
Compassion is a powerful word that describes an intense feeling of commiseration and a desire to help those struck by misfortune. Most people know intuitively how and when to offer compassion to relieve another person's suffering. In health care, compassion is a constant; it cannot be rationed because emergency nurses have limited time or resources to manage increasing demands.
Scóccola, Claudia G; Vucetich, Hector
2008-01-01
We study the role of fundamental constants in an updated recombination scenario. We focus on the time variation of the fine structure constant, and the electron mass in the early Universe, and put bounds on these quantities by using data from CMB including WMAP 5-yr release and the 2dFGRS power spectrum. We analyze how the constraints are modified when changing the recombination scenario.
Minimal surfaces in symmetric spaces with parallel second fundamental form
Indian Academy of Sciences (India)
XIAOXIANG JIAO; MINGYAN LI
2017-09-01
In this paper, we study geometry of isometric minimal immersions of Riemannian surfaces in a symmetric space by moving frames and prove that the Gaussian curvature must be constant if the immersion is of parallel second fundamental form. In particular, when the surface is $S^2$, we discuss the special case and obtain a necessary and sufficient condition such that its second fundamental form is parallel. We alsoconsider isometric minimal two-spheres immersed in complex two-dimensional Kählersymmetric spaces with parallel second fundamental form, and prove that the immersionis totally geodesic with constant Kähler angle if it is neither holomorphic nor antiholomorphicwith Kähler angle $\\alpha\
Cosmological models with constant deceleration parameter
Energy Technology Data Exchange (ETDEWEB)
Berman, M.S.; de Mello Gomide, F.
1988-02-01
Berman presented elsewhere a law of variation for Hubble's parameter that yields constant deceleration parameter models of the universe. By analyzing Einstein, Pryce-Hoyle and Brans-Dicke cosmologies, we derive here the necessary relations in each model, considering a perfect fluid.
Fundamentals of nuclear physics
Takigawa, Noboru
2017-01-01
This book introduces the current understanding of the fundamentals of nuclear physics by referring to key experimental data and by providing a theoretical understanding of principal nuclear properties. It primarily covers the structure of nuclei at low excitation in detail. It also examines nuclear forces and decay properties. In addition to fundamentals, the book treats several new research areas such as non-relativistic as well as relativistic Hartree–Fock calculations, the synthesis of super-heavy elements, the quantum chromodynamics phase diagram, and nucleosynthesis in stars, to convey to readers the flavor of current research frontiers in nuclear physics. The authors explain semi-classical arguments and derivation of its formulae. In these ways an intuitive understanding of complex nuclear phenomena is provided. The book is aimed at graduate school students as well as junior and senior undergraduate students and postdoctoral fellows. It is also useful for researchers to update their knowledge of diver...
Fundamentals of differential beamforming
Benesty, Jacob; Pan, Chao
2016-01-01
This book provides a systematic study of the fundamental theory and methods of beamforming with differential microphone arrays (DMAs), or differential beamforming in short. It begins with a brief overview of differential beamforming and some popularly used DMA beampatterns such as the dipole, cardioid, hypercardioid, and supercardioid, before providing essential background knowledge on orthogonal functions and orthogonal polynomials, which form the basis of differential beamforming. From a physical perspective, a DMA of a given order is defined as an array that measures the differential acoustic pressure field of that order; such an array has a beampattern in the form of a polynomial whose degree is equal to the DMA order. Therefore, the fundamental and core problem of differential beamforming boils down to the design of beampatterns with orthogonal polynomials. But certain constraints also have to be considered so that the resulting beamformer does not seriously amplify the sensors’ self noise and the mism...
Fundamentals of Polarized Light
Mishchenko, Michael
2003-01-01
The analytical and numerical basis for describing scattering properties of media composed of small discrete particles is formed by the classical electromagnetic theory. Although there are several excellent textbooks outlining the fundamentals of this theory, it is convenient for our purposes to begin with a summary of those concepts and equations that are central to the subject of this book and will be used extensively in the following chapters. We start by formulating Maxwell's equations and constitutive relations for time- harmonic macroscopic electromagnetic fields and derive the simplest plane-wave solution that underlies the basic optical idea of a monochromatic parallel beam of light. This solution naturally leads to the introduction of such fundamental quantities as the refractive index and the Stokes parameters. Finally, we define the concept of a quasi-monochromatic beam of light and discuss its implications.
2004-01-01
Discussing what is fundamental in a variety of fields, biologist Richard Dawkins, physicist Gerardus 't Hooft, and mathematician Alain Connes spoke to a packed Main Auditorium at CERN 15 October. Dawkins, Professor of the Public Understanding of Science at Oxford University, explained simply the logic behind Darwinian natural selection, and how it would seem to apply anywhere in the universe that had the right conditions. 't Hooft, winner of the 1999 Physics Nobel Prize, outlined some of the main problems in physics today, and said he thinks physics is so fundamental that even alien scientists from another planet would likely come up with the same basic principles, such as relativity and quantum mechanics. Connes, winner of the 1982 Fields Medal (often called the Nobel Prize of Mathematics), explained how physics is different from mathematics, which he described as a "factory for concepts," unfettered by connection to the physical world. On 16 October, anthropologist Sharon Traweek shared anecdotes from her ...
Fundamental composite electroweak dynamics
DEFF Research Database (Denmark)
Arbey, Alexandre; Cacciapaglia, Giacomo; Cai, Haiying
2017-01-01
Using the recent joint results from the ATLAS and CMS collaborations on the Higgs boson, we determine the current status of composite electroweak dynamics models based on the expected scalar sector. Our analysis can be used as a minimal template for a wider class of models between the two limiting...... cases of composite Goldstone Higgs and Technicolor-like ones. This is possible due to the existence of a unified description, both at the effective and fundamental Lagrangian levels, of models of composite Higgs dynamics where the Higgs boson itself can emerge, depending on the way the electroweak...... space at the effective Lagrangian level. We show that a wide class of models of fundamental composite electroweak dynamics are still compatible with the present constraints. The results are relevant for the ongoing and future searches at the Large Hadron Collider....
Fundamentals of Stochastic Networks
Ibe, Oliver C
2011-01-01
An interdisciplinary approach to understanding queueing and graphical networks In today's era of interdisciplinary studies and research activities, network models are becoming increasingly important in various areas where they have not regularly been used. Combining techniques from stochastic processes and graph theory to analyze the behavior of networks, Fundamentals of Stochastic Networks provides an interdisciplinary approach by including practical applications of these stochastic networks in various fields of study, from engineering and operations management to communications and the physi
Fundamentals of queueing theory
Gross, Donald; Thompson, James M; Harris, Carl M
2013-01-01
Praise for the Third Edition ""This is one of the best books available. Its excellent organizational structure allows quick reference to specific models and its clear presentation . . . solidifies the understanding of the concepts being presented.""-IIE Transactions on Operations Engineering Thoroughly revised and expanded to reflect the latest developments in the field, Fundamentals of Queueing Theory, Fourth Edition continues to present the basic statistical principles that are necessary to analyze the probabilistic nature of queues. Rather than pre
Energy Technology Data Exchange (ETDEWEB)
Wollaber, Allan Benton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-06-16
This is a powerpoint presentation which serves as lecture material for the Parallel Computing summer school. It goes over the fundamentals of the Monte Carlo calculation method. The material is presented according to the following outline: Introduction (background, a simple example: estimating π), Why does this even work? (The Law of Large Numbers, The Central Limit Theorem), How to sample (inverse transform sampling, rejection), and An example from particle transport.
High voltage engineering fundamentals
Kuffel, E; Hammond, P
1984-01-01
Provides a comprehensive treatment of high voltage engineering fundamentals at the introductory and intermediate levels. It covers: techniques used for generation and measurement of high direct, alternating and surge voltages for general application in industrial testing and selected special examples found in basic research; analytical and numerical calculation of electrostatic fields in simple practical insulation system; basic ionisation and decay processes in gases and breakdown mechanisms of gaseous, liquid and solid dielectrics; partial discharges and modern discharge detectors; and over
Biomedical engineering fundamentals
Bronzino, Joseph D
2014-01-01
Known as the bible of biomedical engineering, The Biomedical Engineering Handbook, Fourth Edition, sets the standard against which all other references of this nature are measured. As such, it has served as a major resource for both skilled professionals and novices to biomedical engineering.Biomedical Engineering Fundamentals, the first volume of the handbook, presents material from respected scientists with diverse backgrounds in physiological systems, biomechanics, biomaterials, bioelectric phenomena, and neuroengineering. More than three dozen specific topics are examined, including cardia
Greg Hall, D
2011-01-01
Session 1 of the 2010 STP/IFSTP Joint Symposium on Toxicologic Neuropathology, titled "Fundamentals of Neurobiology," was organized to provide a foundation for subsequent sessions by presenting essential elements of neuroanatomy and nervous system function. A brief introduction to the session titled "Introduction to Correlative Neurobiology" was provided by Dr. Greg Hall (Eli Lilly and Company, Indianapolis, IN). Correlative neurobiology refers to considerations of the relationships between the highly organized and compartmentalized structure of nervous tissues and the functioning within this system.
Duane Knudson
2007-01-01
DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follow...
Fundamentals of linear algebra
Dash, Rajani Ballav
2008-01-01
FUNDAMENTALS OF LINEAR ALGEBRA is a comprehensive Text Book, which can be used by students and teachers of All Indian Universities. The Text has easy, understandable form and covers all topics of UGC Curriculum. There are lots of worked out examples which helps the students in solving the problems without anybody's help. The Problem sets have been designed keeping in view of the questions asked in different examinations.
Neutrons and Fundamental Symmetries
Energy Technology Data Exchange (ETDEWEB)
Plaster, Bradley [Univ. of Kentucky, Lexington, KY (United States). Dept. of Physics and Astronomy
2016-01-11
The research supported by this project addressed fundamental open physics questions via experiments with subatomic particles. In particular, neutrons constitute an especially ideal “laboratory” for fundamental physics tests, as their sensitivities to the four known forces of nature permit a broad range of tests of the so-called “Standard Model”, our current best physics model for the interactions of subatomic particles. Although the Standard Model has been a triumphant success for physics, it does not provide satisfactory answers to some of the most fundamental open questions in physics, such as: are there additional forces of nature beyond the gravitational, electromagnetic, weak nuclear, and strong nuclear forces?, or why does our universe consist of more matter than anti-matter? This project also contributed significantly to the training of the next generation of scientists, of considerable value to the public. Young scientists, ranging from undergraduate students to graduate students to post-doctoral researchers, made significant contributions to the work carried out under this project.
Burov, Alexey
Fundamental science is a hard, long-term human adventure that has required high devotion and social support, especially significant in our epoch of Mega-science. The measure of this devotion and this support expresses the real value of the fundamental science in public opinion. Why does fundamental science have value? What determines its strength and what endangers it? The dominant answer is that the value of science arises out of curiosity and is supported by the technological progress. Is this really a good, astute answer? When trying to attract public support, we talk about the ``mystery of the universe''. Why do these words sound so attractive? What is implied by and what is incompatible with them? More than two centuries ago, Immanuel Kant asserted an inseparable entanglement between ethics and metaphysics. Thus, we may ask: which metaphysics supports the value of scientific cognition, and which does not? Should we continue to neglect the dependence of value of pure science on metaphysics? If not, how can this issue be addressed in the public outreach? Is the public alienated by one or another message coming from the face of science? What does it mean to be politically correct in this sort of discussion?
Can compactifications solve the cosmological constant problem?
Energy Technology Data Exchange (ETDEWEB)
Hertzberg, Mark P. [Institute of Cosmology, Department of Physics and Astronomy, Tufts University,574 Boston Ave, Medford, MA 02155 (United States); Center for Theoretical Physics, Department of Physics,Massachusetts Institute of Technology,77 Massachusetts Ave, Cambridge, MA 02139 (United States); Masoumi, Ali [Institute of Cosmology, Department of Physics and Astronomy, Tufts University,574 Boston Ave, Medford, MA 02155 (United States)
2016-06-30
Recently, there have been claims in the literature that the cosmological constant problem can be dynamically solved by specific compactifications of gravity from higher-dimensional toy models. These models have the novel feature that in the four-dimensional theory, the cosmological constant Λ is much smaller than the Planck density and in fact accumulates at Λ=0. Here we show that while these are very interesting models, they do not properly address the real cosmological constant problem. As we explain, the real problem is not simply to obtain Λ that is small in Planck units in a toy model, but to explain why Λ is much smaller than other mass scales (and combinations of scales) in the theory. Instead, in these toy models, all other particle mass scales have been either removed or sent to zero, thus ignoring the real problem. To this end, we provide a general argument that the included moduli masses are generically of order Hubble, so sending them to zero trivially sends the cosmological constant to zero. We also show that the fundamental Planck mass is being sent to zero, and so the central problem is trivially avoided by removing high energy physics altogether. On the other hand, by including various large mass scales from particle physics with a high fundamental Planck mass, one is faced with a real problem, whose only known solution involves accidental cancellations in a landscape.
Possible evidence for a variable fine structure constant from QSO absorption lines systematic errors
Murphy, M T; Flambaum, V V; Churchill, C W; Prochaska, J X
2001-01-01
Comparison of quasar absorption spectra with laboratory spectra allow us to probe possible variations in the fundamental constants over cosmological time-scales. In a companion paper we present an analysis of Keck/HIRES spectra and report possible evidence suggesting that the fine structure constant, alpha, may have been smaller in the past: da/a = (-0.72 +/- 0.18) * 10^{-5} over the redshift range 0.5 < z < 3.5. In this paper we describe a comprehensive investigation into possible systematic effects. Most of these do not significantly influence our results. When we correct for those which do produce a significant systematic effect in the data, the deviation of da/a from zero becomes more significant. We are lead increasingly to the interpretation that alpha was slightly smaller in the past.
Sorensen, E
1940-01-01
The conventional axial blowers operate on the high-pressure principle. One drawback of this type of blower is the relatively low pressure head, which one attempts to overcome with axial blowers producing very high pressure at a given circumferential speed. The Schicht constant-pressure blower affords pressure ratios considerably higher than those of axial blowers of conventional design with approximately the same efficiency.
String Scale Cosmological Constant
Chalmers, Gordon
2006-01-01
The cosmological constant is an unexplained until now phenomena of nature that requires an explanation through string effects. The apparent discrepancy between theory and experiment is enourmous and has already been explained several times by the author including mechanisms. In this work the string theory theory of abolished string modes is documented and given perturbatively to all loop orders. The holographic underpinning is also exposed. The matching with the data of the LIGO and D0 experi...
Elsgolc, L E; Stark, M
1961-01-01
Calculus of Variations aims to provide an understanding of the basic notions and standard methods of the calculus of variations, including the direct methods of solution of the variational problems. The wide variety of applications of variational methods to different fields of mechanics and technology has made it essential for engineers to learn the fundamentals of the calculus of variations. The book begins with a discussion of the method of variation in problems with fixed boundaries. Subsequent chapters cover variational problems with movable boundaries and some other problems; sufficiency
Jackson, Neal
2015-01-01
I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H0 values of around 72-74 km s(-1) Mpc(-1), with typical errors of 2-3 km s(-1) Mpc(-1). This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67-68 km s(-1) Mpc(-1) and typical errors of 1-2 km s(-1) Mpc(-1). The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.
Yongquan, Han
2016-10-01
The ideal gas state equation is not applicable to ordinary gas, it should be applied to the Electromagnetic ``gas'' that is applied to the radiation, the radiation should be the ultimate state of matter changes or initial state, the universe is filled with radiation. That is, the ideal gas equation of state is suitable for the Singular point and the universe. Maybe someone consider that, there is no vessel can accommodate radiation, it is because the Ordinary container is too small to accommodate, if the radius of your container is the distance that Light through an hour, would you still think it can't accommodates radiation? Modern scientific determinate that the radius of the universe now is about 1027 m, assuming that the universe is a sphere whose volume is approximately: V = 4.19 × 1081 cubic meters, the temperature radiation of the universe (cosmic microwave background radiation temperature of the universe, should be the closest the average temperature of the universe) T = 3.15k, radiation pressure P = 5 × 10-6 N / m 2, according to the law of ideal gas state equation, PV / T = constant = 6 × 1075, the value of this constant is the universe, The singular point should also equal to the constant Author: hanyongquan
Institute of Scientific and Technical Information of China (English)
郝琦蕾; 刘红霞; 计翔
2006-01-01
We used the Mongolian racerunner Eremias argus as a model animal to evaluate the effects of constant versus fluctuating incubation temperatures on hatching success and hatchling phenotypes. Eggs were incubated under four constant [24, 27, 30 and 33 ( ± 0.3)℃ ] and one fluctuating temperature regimes. Hatching success did not differ among treatments, and incubation temperature did not affect the sexual phenotype of hatchlings. Incubation length decreased exponentially as incubation temperature increased, and eggs incubated at fluctuating temperatures took a longer time to complete development than did those incubated at constant temperatures with the same mean. Of the hatchling phenotypes examined, body dry mass, carcass dry mass, residual yolk dry mass and locomotor performance of hatchlings were more likely to be affected by incubation temperature. Overall, locomotor performance was best in the low temperature treatments (24℃ and 27℃ ) and worst in the highest temperature treatment (33℃), with the moderate temperature treatments (30℃ and fluctuating temperatures) in between. Our data show that: (1) daily exposure of eggs to extreme temperatures that are potentially lethal to embryos for brief periods does not have detectable adverse effects on hatching success and morphological phenotypes in E. argus; and (2) thermal fluctuations exert no positive effects on locomotor performance of hatchlings but influence incubation length differently than constant temperatures with the same mean [ Acta Zoologica Sinica 52 (6): 1049-1057, 2006].%作者以丽斑麻蜥(Eremias argus)为模型动物研究恒定和波动孵化温度对孵化成功率和孵出幼体表型的影响.卵在四个恒定[24,27,30 and 33(±0.3)℃]、一个波动温度下孵化.不同温度处理下的孵化成功率相同,但孵出幼体表型不同.孵化期随孵化温度升高呈指数式缩短;在相同平均温度下,波动温度孵化卵的孵化期比恒温孵化卵长.在所有被检
Directory of Open Access Journals (Sweden)
Duane Knudson
2007-09-01
Full Text Available DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follows: Part 1 Introduction: 1.Introduction to biomechanics of human movement; 2.Fundamentals of biomechanics and qualitative analysis; Part 2 Biological/Structural Bases: 3.Anatomical description and its limitations; 4.Mechanics of the musculoskeletal system; Part 3 Mechanical Bases: 5.Linear and angular kinematics; 6.Linear kinetics; 7.Angular kinetics; 8.Fluid mechanics; Part 4 Application of Biomechanics in Qualitative Analysis :9.Applying biomechanics in physical education; 10.Applying biomechanics in coaching; 11.Applying biomechanics in strength and conditioning; 12.Applying biomechanics in sports medicine and rehabilitation. AUDIENCE This is an important reading for both student and educators in the medicine, sport and exercise-related fields. For the researcher and lecturer it would be a helpful guide to plan and prepare more detailed experimental designs or lecture and/or laboratory classes in exercise and sport biomechanics. ASSESSMENT The text provides a constructive fundamental resource for biomechanics, exercise and sport-related students, teachers and researchers as well as anyone interested in understanding motion. It is also very useful since being clearly written and presenting several ways of examples of the application of biomechanics to help teach and apply biomechanical variables and concepts, including sport-related ones
Information security fundamentals
Blackley, John A; Peltier, Justin
2004-01-01
Effective security rules and procedures do not exist for their own sake-they are put in place to protect critical assets, thereby supporting overall business objectives. Recognizing security as a business enabler is the first step in building a successful program.Information Security Fundamentals allows future security professionals to gain a solid understanding of the foundations of the field and the entire range of issues that practitioners must address. This book enables students to understand the key elements that comprise a successful information security program and eventually apply thes
Directory of Open Access Journals (Sweden)
Carlos A. Robles Corbalá
2015-12-01
Full Text Available En este artículo se aborda un problema clásico para poder detectar si dos espacios topológicos son homeomorfos o no. Para lo cual a cada espacio topológico se le asocia un grupo algebraico, de tal suerte que si los espacios son homeomorfos, entonces los grupos asociados serán isomorfos. Se presenta una construcción del grupo fundamental de un espacio topológico y se enfoca en demostrar que efectivamente es un grupo.
Morris, Carla C
2015-01-01
Fundamentals of Calculus encourages students to use power, quotient, and product rules for solutions as well as stresses the importance of modeling skills. In addition to core integral and differential calculus coverage, the book features finite calculus, which lends itself to modeling and spreadsheets. Specifically, finite calculus is applied to marginal economic analysis, finance, growth, and decay. Includes: Linear Equations and FunctionsThe DerivativeUsing the Derivative Exponential and Logarithmic Functions Techniques of DifferentiationIntegral CalculusIntegration TechniquesFunctions
Fundamentals of attosecond optics
Chang, Zenghu
2011-01-01
Attosecond optical pulse generation, along with the related process of high-order harmonic generation, is redefining ultrafast physics and chemistry. A practical understanding of attosecond optics requires significant background information and foundational theory to make full use of these cutting-edge lasers and advance the technology toward the next generation of ultrafast lasers. Fundamentals of Attosecond Optics provides the first focused introduction to the field. The author presents the underlying concepts and techniques required to enter the field, as well as recent research advances th
Fundamentals of microwave photonics
Urick, V J; McKinney , Jason D
2015-01-01
A comprehensive resource to designing andconstructing analog photonic links capable of high RFperformanceFundamentals of Microwave Photonics provides acomprehensive description of analog optical links from basicprinciples to applications. The book is organized into fourparts. The first begins with a historical perspective of microwavephotonics, listing the advantages of fiber optic links anddelineating analog vs. digital links. The second section coversbasic principles associated with microwave photonics in both the RFand optical domains. The third focuses on analog modulationformats-starti
Mathematical analysis fundamentals
Bashirov, Agamirza
2014-01-01
The author's goal is a rigorous presentation of the fundamentals of analysis, starting from elementary level and moving to the advanced coursework. The curriculum of all mathematics (pure or applied) and physics programs include a compulsory course in mathematical analysis. This book will serve as can serve a main textbook of such (one semester) courses. The book can also serve as additional reading for such courses as real analysis, functional analysis, harmonic analysis etc. For non-math major students requiring math beyond calculus, this is a more friendly approach than many math-centric o
Fundamentals of Project Management
Heagney, Joseph
2011-01-01
With sales of more than 160,000 copies, Fundamentals of Project Management has helped generations of project managers navigate the ins and outs of every aspect of this complex discipline. Using a simple step-by-step approach, the book is the perfect introduction to project management tools, techniques, and concepts. Readers will learn how to: ò Develop a mission statement, vision, goals, and objectives ò Plan the project ò Create the work breakdown structure ò Produce a workable schedule ò Understand earned value analysis ò Manage a project team ò Control and evaluate progress at every stage.
Fundamental concepts of mathematics
Goodstein, R L
Fundamental Concepts of Mathematics, 2nd Edition provides an account of some basic concepts in modern mathematics. The book is primarily intended for mathematics teachers and lay people who wants to improve their skills in mathematics. Among the concepts and problems presented in the book include the determination of which integral polynomials have integral solutions; sentence logic and informal set theory; and why four colors is enough to color a map. Unlike in the first edition, the second edition provides detailed solutions to exercises contained in the text. Mathematics teachers and people
Fundamental of biomedical engineering
Sawhney, GS
2007-01-01
About the Book: A well set out textbook explains the fundamentals of biomedical engineering in the areas of biomechanics, biofluid flow, biomaterials, bioinstrumentation and use of computing in biomedical engineering. All these subjects form a basic part of an engineer''s education. The text is admirably suited to meet the needs of the students of mechanical engineering, opting for the elective of Biomedical Engineering. Coverage of bioinstrumentation, biomaterials and computing for biomedical engineers can meet the needs of the students of Electronic & Communication, Electronic & Instrumenta
Franc, Jean-Pierre
2005-01-01
The present book is aimed at providing a comprehensive presentation of cavitation phenomena in liquid flows. It is further backed up by the experience, both experimental and theoretical, of the authors whose expertise has been internationally recognized. A special effort is made to place the various methods of investigation in strong relation with the fundamental physics of cavitation, enabling the reader to treat specific problems independently. Furthermore, it is hoped that a better knowledge of the cavitation phenomenon will allow engineers to create systems using it positively. Examples in the literature show the feasibility of this approach.
Saleh, Bahaa E A
2007-01-01
Now in a new full-color edition, Fundamentals of Photonics, Second Edition is a self-contained and up-to-date introductory-level textbook that thoroughly surveys this rapidly expanding area of engineering and applied physics. Featuring a logical blend of theory and applications, coverage includes detailed accounts of the primary theories of light, including ray optics, wave optics, electromagnetic optics, and photon optics, as well as the interaction of photons and atoms, and semiconductor optics. Presented at increasing levels of complexity, preliminary sections build toward more advan
Nanomachines fundamentals and applications
Wang, Joseph
2013-01-01
This first-hand account by one of the pioneers of nanobiotechnology brings together a wealth of valuable material in a single source. It allows fascinating insights into motion at the nanoscale, showing how the proven principles of biological nanomotors are being transferred to artificial nanodevices.As such, the author provides engineers and scientists with the fundamental knowledge surrounding the design and operation of biological and synthetic nanomotors and the latest advances in nanomachines. He addresses such topics as nanoscale propulsions, natural biomotors, molecular-scale machin
Electronic circuits fundamentals & applications
Tooley, Mike
2015-01-01
Electronics explained in one volume, using both theoretical and practical applications.New chapter on Raspberry PiCompanion website contains free electronic tools to aid learning for students and a question bank for lecturersPractical investigations and questions within each chapter help reinforce learning Mike Tooley provides all the information required to get to grips with the fundamentals of electronics, detailing the underpinning knowledge necessary to appreciate the operation of a wide range of electronic circuits, including amplifiers, logic circuits, power supplies and oscillators. The
Fundamentals of watershed hydrology
Pamela J. Edwards; Karl W.J. Williard; Jon E. Schoonover
2015-01-01
This is a primer about hydrology, the science of water. Watersheds are the basic land unit for water resource management and their delineation, importance, and variation are explained and illustrated. The hydrologic cycle and its components (precipitation, evaporation, transpiration, soil water, groundwater, and streamflow) which collectively provide a foundation for...
Directory of Open Access Journals (Sweden)
Neal Jackson
2015-09-01
Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H_0 values of around 72–74 km s^–1 Mpc^–1, with typical errors of 2–3 km s^–1 Mpc^–1. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67–68 km s^–1 Mpc^–1 and typical errors of 1–2 km s^–1 Mpc^–1. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.
Wolf, Joseph A
2010-01-01
This book is the sixth edition of the classic Spaces of Constant Curvature, first published in 1967, with the previous (fifth) edition published in 1984. It illustrates the high degree of interplay between group theory and geometry. The reader will benefit from the very concise treatments of riemannian and pseudo-riemannian manifolds and their curvatures, of the representation theory of finite groups, and of indications of recent progress in discrete subgroups of Lie groups. Part I is a brief introduction to differentiable manifolds, covering spaces, and riemannian and pseudo-riemannian geomet
Testing Our Fundamental Assumptions
Kohler, Susanna
2016-06-01
Science is all about testing the things we take for granted including some of the most fundamental aspects of how we understand our universe. Is the speed of light in a vacuum the same for all photons regardless of their energy? Is the rest mass of a photon actually zero? A series of recent studies explore the possibility of using transient astrophysical sources for tests!Explaining Different Arrival TimesArtists illustration of a gamma-ray burst, another extragalactic transient, in a star-forming region. [NASA/Swift/Mary Pat Hrybyk-Keith and John Jones]Suppose you observe a distant transient astrophysical source like a gamma-ray burst, or a flare from an active nucleus and two photons of different energies arrive at your telescope at different times. This difference in arrival times could be due to several different factors, depending on how deeply you want to question some of our fundamental assumptions about physics:Intrinsic delayThe photons may simply have been emitted at two different times by the astrophysical source.Delay due to Lorentz invariance violationPerhaps the assumption that all massless particles (even two photons with different energies) move at the exact same velocity in a vacuum is incorrect.Special-relativistic delayMaybe there is a universal speed for massless particles, but the assumption that photons have zero rest mass is wrong. This, too, would cause photon velocities to be energy-dependent.Delay due to gravitational potentialPerhaps our understanding of the gravitational potential that the photons experience as they travel is incorrect, also causing different flight times for photons of different energies. This would mean that Einsteins equivalence principle, a fundamental tenet of general relativity (GR), is incorrect.If we now turn this problem around, then by measuring the arrival time delay between photons of different energies from various astrophysical sources the further away, the better we can provide constraints on these
Pisacane, Vincent L.
2005-06-01
Fundamentals of Space Systems was developed to satisfy two objectives: the first is to provide a text suitable for use in an advanced undergraduate or beginning graduate course in both space systems engineering and space system design. The second is to be a primer and reference book for space professionals wishing to broaden their capabilities to develop, manage the development, or operate space systems. The authors of the individual chapters are practicing engineers that have had extensive experience in developing sophisticated experimental and operational spacecraft systems in addition to having experience teaching the subject material. The text presents the fundamentals of all the subsystems of a spacecraft missions and includes illustrative examples drawn from actual experience to enhance the learning experience. It included a chapter on each of the relevant major disciplines and subsystems including space systems engineering, space environment, astrodynamics, propulsion and flight mechanics, attitude determination and control, power systems, thermal control, configuration management and structures, communications, command and telemetry, data processing, embedded flight software, survuvability and reliability, integration and test, mission operations, and the initial conceptual design of a typical small spacecraft mission.
1983-12-01
Various topics dealing with the constants of physics are addressed. The subjects considered include: measurement of the fundamental constants; the search for proton decay; the constancy of G; limits on the variability of coupling constants from the Oklo natural reactor; implications of quasar spectroscopy for constancy of constants; theoretical prospects for understanding the values of fundamental constants; the strong, electromagnetic, and weak couplings; and field theories without fundamental gauge symmetries. Also discussed are: Einstein gravitation as a long-wavelength effective field theory; unification and supersymmetry; phase transitions in the early universe; the cosmological constant; large numbers and ratios in astrophysics and cosmology; dependence of macrophysical phenomena on the values of the fundamental constants; dimensionality; and the anthropic principle and its implications for biological evolution.
Energy Technology Data Exchange (ETDEWEB)
Li, Shuo [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Li, Zhanlong; Wang, Shenghan; Gao, Shuqin [College of Physics, Jilin University, Changchun 130012 (China); Sun, Chenglin, E-mail: chenglin@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Li, Zuowei [College of Physics, Jilin University, Changchun 130012 (China)
2015-12-15
Highlights: • The Huang–Rhys factors and electron–phonon coupling constants are calculated. • The changes of overtone mode are larger than those of fundamental mode. • The variation pattern of electron–phonon coupling well interprets the changes of spectra. - Abstract: External field plays a very important role in the interaction between the π-electron transition and atomic vibration of polyenes. It has significant effects on both the Huang–Rhys factor and the electron–phonon coupling. In this paper, the visible absorption and resonance Raman spectra of all-trans-β-carotene are measured in the 345–295 K temperature range and it is found that the changes of the 0–1 and 0–2 vibration bands of the absorption spectra with the temperature lead to the different electron–phonon coupling of fundamental, overtone, and combination modes. The electron-phonon coupling constants of all the modes are calculated and analyzed under different temperatures. The variation law of the electron–phonon coupling with the temperature well interprets the changes of the resonance Raman spectra, such as the shift, intensity and line width of the overtone and combination modes, which are all greater than those of the fundamental modes.
Digital Fourier analysis fundamentals
Kido, Ken'iti
2015-01-01
This textbook is a thorough, accessible introduction to digital Fourier analysis for undergraduate students in the sciences. Beginning with the principles of sine/cosine decomposition, the reader walks through the principles of discrete Fourier analysis before reaching the cornerstone of signal processing: the Fast Fourier Transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Fundamentals" includes practice problems and thorough Appendices for the advanced reader. As a special feature, the book includes interactive applets (available online) that mirror the illustrations. These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. For example, a real sine signal can be treated as a sum of clockwise and counter-clockwise rotating vectors. The applet illustration included with the book animates the rotating vectors and the resulting sine signal. By changing parameters such as amplitude and frequency, the reader ca...
Fundamentals of quantum mechanics
House, J E
2017-01-01
Fundamentals of Quantum Mechanics, Third Edition is a clear and detailed introduction to quantum mechanics and its applications in chemistry and physics. All required math is clearly explained, including intermediate steps in derivations, and concise review of the math is included in the text at appropriate points. Most of the elementary quantum mechanical models-including particles in boxes, rigid rotor, harmonic oscillator, barrier penetration, hydrogen atom-are clearly and completely presented. Applications of these models to selected “real world” topics are also included. This new edition includes many new topics such as band theory and heat capacity of solids, spectroscopy of molecules and complexes (including applications to ligand field theory), and small molecules of astrophysical interest.
Fundamental partial compositeness
Sannino, Francesco
2016-01-01
We construct renormalizable Standard Model extensions, valid up to the Planck scale, that give a composite Higgs from a new fundamental strong force acting on fermions and scalars. Yukawa interactions of these particles with Standard Model fermions realize the partial compositeness scenario. Successful models exist because gauge quantum numbers of Standard Model fermions admit a minimal enough 'square root'. Furthermore, right-handed SM fermions have an SU(2)$_R$-like structure, yielding a custodially-protected composite Higgs. Baryon and lepton numbers arise accidentally. Standard Model fermions acquire mass at tree level, while the Higgs potential and flavor violations are generated by quantum corrections. We further discuss accidental symmetries and other dynamical features stemming from the new strongly interacting scalars. If the same phenomenology can be obtained from models without our elementary scalars, they would reappear as composite states.
Lasers Fundamentals and Applications
Thyagarajan, K
2010-01-01
Lasers: Fundamentals and Applications, serves as a vital textbook to accompany undergraduate and graduate courses on lasers and their applications. Ever since their invention in 1960, lasers have assumed tremendous importance in the fields of science, engineering and technology because of their diverse uses in basic research and countless technological applications. This book provides a coherent presentation of the basic physics behind the way lasers work, and presents some of their most important applications in vivid detail. After reading this book, students will understand how to apply the concepts found within to practical, tangible situations. This textbook includes worked-out examples and exercises to enhance understanding, and the preface shows lecturers how to most beneficially match the textbook with their course curricula. The book includes several recent Nobel Lectures, which will further expose students to the emerging applications and excitement of working with lasers. Students who study lasers, ...
Fundamentals of Structural Engineering
Connor, Jerome J
2013-01-01
Fundamentals of Structural Engineering provides a balanced, seamless treatment of both classic, analytic methods and contemporary, computer-based techniques for conceptualizing and designing a structure. The book’s principle goal is to foster an intuitive understanding of structural behavior based on problem solving experience for students of civil engineering and architecture who have been exposed to the basic concepts of engineering mechanics and mechanics of materials. Making it distinct from many other undergraduate textbooks, the authors of this text recognize the notion that engineers reason about behavior using simple models and intuition they acquire through problem solving. The approach adopted in this text develops this type of intuition by presenting extensive, realistic problems and case studies together with computer simulation, which allows rapid exploration of how a structure responds to changes in geometry and physical parameters. This book also: Emphasizes problem-based understanding of...
Fundamentals of sustainable neighbourhoods
Friedman, Avi
2015-01-01
This book introduces architects, engineers, builders, and urban planners to a range of design principles of sustainable communities and illustrates them with outstanding case studies. Drawing on the author’s experience as well as local and international case studies, Fundamentals of Sustainable Neighbourhoods presents planning concepts that minimize developments' carbon footprint through compact communities, adaptable and expandable dwellings, adaptable landscapes, and smaller-sized yet quality-designed housing. This book also: Examines in-depth global strategies for minimizing the residential carbon footprint, including district heating, passive solar gain, net-zero residences, as well as preserving the communities' natural assets Reconsiders conceptual approaches in building design and urban planning to promote a better connection between communities and nature Demonstrates practical applications of green architecture Focuses on innovative living spaces in urban environments
Yen, William M; Yamamoto, Hajime
2006-01-01
Drawing from the second edition of the best-selling Handbook of Phosphors, Fundamentals of Phosphors covers the principles and mechanisms of luminescence in detail and surveys the primary phosphor materials as well as their optical properties. The book addresses cutting-edge developments in phosphor science and technology including oxynitride phosphors and the impact of lanthanide level location on phosphor performance.Beginning with an explanation of the physics underlying luminescence mechanisms in solids, the book goes on to interpret various luminescence phenomena in inorganic and organic materials. This includes the interpretation of the luminescence of recently developed low-dimensional systems, such as quantum wells and dots. The book also discusses the excitation mechanisms by cathode-ray and ionizing radiation and by electric fields to produce electroluminescence. The book classifies phosphor materials according to the type of luminescence centers employed or the class of host materials used and inte...
Superconductivity fundamentals and applications
Buckel, Werner
2004-01-01
This is the second English edition of what has become one of the definitive works on superconductivity in German -- currently in its sixth edition. Comprehensive and easy to understand, this introductory text is written especially with the non-specialist in mind. The authors, both long-term experts in this field, present the fundamental considerations without the need for extensive mathematics, describing the various phenomena connected with the superconducting state, with liberal insertion of experimental facts and examples for modern applications. While all fields of superconducting phenomena are dealt with in detail, this new edition pays particular attention to the groundbreaking discovery of magnesium diboride and the current developments in this field. In addition, a new chapter provides an overview of the elements, alloys and compounds where superconductivity has been observed in experiments, together with their major characteristics. The chapter on technical applications has been considerably expanded...
Fundamentals of Fire Phenomena
DEFF Research Database (Denmark)
Quintiere, James
discipline. It covers thermo chemistry including mixtures and chemical reactions; Introduces combustion to the fire protection student; Discusses premixed flames and spontaneous ignition; Presents conservation laws for control volumes, including the effects of fire; Describes the theoretical bases...... analyses. Fire phenomena encompass everything about the scientific principles behind fire behaviour. Combining the principles of chemistry, physics, heat and mass transfer, and fluid dynamics necessary to understand the fundamentals of fire phenomena, this book integrates the subject into a clear...... for empirical aspects of the subject of fire; Analyses ignition of liquids and the importance of evaporation including heat and mass transfer; Features the stages of fire in compartments, and the role of scale modelling in fire. The book is written by Prof. James G. Quintiere from University of Maryland...
Automotive electronics design fundamentals
Zaman, Najamuz
2015-01-01
This book explains the topology behind automotive electronics architectures and examines how they can be profoundly augmented with embedded controllers. These controllers serve as the core building blocks of today’s vehicle electronics. Rather than simply teaching electrical basics, this unique resource focuses on the fundamental concepts of vehicle electronics architecture, and details the wide variety of Electronic Control Modules (ECMs) that enable the increasingly sophisticated "bells & whistles" of modern designs. A must-have for automotive design engineers, technicians working in automotive electronics repair centers and students taking automotive electronics courses, this guide bridges the gap between academic instruction and industry practice with clear, concise advice on how to design and optimize automotive electronics with embedded controllers.
Fundamentals of Fire Phenomena
DEFF Research Database (Denmark)
Quintiere, James
Understanding fire dynamics and combustion is essential in fire safety engineering and in fire science curricula. Engineers and students involved in fire protection, safety and investigation need to know and predict how fire behaves to be able to implement adequate safety measures and hazard...... analyses. Fire phenomena encompass everything about the scientific principles behind fire behaviour. Combining the principles of chemistry, physics, heat and mass transfer, and fluid dynamics necessary to understand the fundamentals of fire phenomena, this book integrates the subject into a clear...... discipline. It covers thermo chemistry including mixtures and chemical reactions; Introduces combustion to the fire protection student; Discusses premixed flames and spontaneous ignition; Presents conservation laws for control volumes, including the effects of fire; Describes the theoretical bases...
WMAP 5-year constraints on time variation of $\\alpha$ and $m_e$
Scóccola, Claudia G; Vucetich, Hector
2009-01-01
We studied the role of fundamental constants in an updated recombination scenario, focusing on the time variation of the fine structure constant \\alpha and the electron mass m_e in the early Universe. Using CMB data including WMAP 5-yr release, and the 2dFGRS power spectrum, we put bounds on variations of these constants, when both constants are allowed to vary, and in the case that only one of them is variable. In particular, we have found that -0.019 < \\Delta \\alpha / \\alpha_0 < 0.017 (95% c.l.), in our joint estimation of \\alpha and cosmological parameters. Finally, we analyze how the constraints depends on the recombination scenario.
Directory of Open Access Journals (Sweden)
Jackson Neal
2007-09-01
Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. In the last 20 years, much progress has been made and estimates now range between 60 and 75 km s^-1 Mpc^-1, with most now between 70 and 75 km s^-1 Mpc^-1, a huge improvement over the factor-of-2 uncertainty which used to prevail. Further improvements which gave a generally agreed margin of error of a few percent rather than the current 10% would be vital input to much other interesting cosmology. There are several programmes which are likely to lead us to this point in the next 10 years.
Energy Technology Data Exchange (ETDEWEB)
Beiu, V.
1997-04-01
In this paper the authors discuss several complexity aspects pertaining to neural networks, commonly known as the curse of dimensionality. The focus will be on: (1) size complexity and depth-size tradeoffs; (2) complexity of learning; and (3) precision and limited interconnectivity. Results have been obtained for each of these problems when dealt with separately, but few things are known as to the links among them. They start by presenting known results and try to establish connections between them. These show that they are facing very difficult problems--exponential growth in either space (i.e. precision and size) and/or time (i.e., learning and depth)--when resorting to neural networks for solving general problems. The paper will present a solution for lowering some constants, by playing on the depth-size tradeoff.
Fundamentals of ergonomic exoskeleton robots
Schiele, A.
2008-01-01
This thesis is the first to provide the fundamentals of ergonomic exoskeleton design. The fundamental theory as well as technology necessary to analyze and develop ergonomic wearable robots interacting with humans is established and validated by experiments and prototypes. The fundamentals are (1) a
Fundamentals of ergonomic exoskeleton robots
Schiele, A.
2008-01-01
This thesis is the first to provide the fundamentals of ergonomic exoskeleton design. The fundamental theory as well as technology necessary to analyze and develop ergonomic wearable robots interacting with humans is established and validated by experiments and prototypes. The fundamentals are (1) a
Yan, Mu-Lin; Hu, Sen; Huang, Wei; Xiao, Neng-Chao
2011-01-01
The recent OPERA experiment of superluminal neutrinos has deep consequences in cosmology. In cosmology a fundamental constant is the cosmological constant. From observations one can estimate the effective cosmological constant $\\Lambda_{eff}$ which is the sum of the quantum zero point energy $\\Lambda_{dark energy}$ and the geometric cosmological constant $\\Lambda$. The OPERA experiment can be applied to determine the geometric cosmological constant $\\Lambda$. It is the first time to distingui...
Fundamentals of klystron testing
Energy Technology Data Exchange (ETDEWEB)
Caldwell, J.W. Jr.
1978-08-01
Fundamentals of klystron testing is a text primarily intended for the indoctrination of new klystron group test stand operators. It should significantly reduce the familiarization time of a new operator, making him an asset to the group sooner than has been experienced in the past. The new employee must appreciate the mission of SLAC before he can rightfully be expected to make a meaningful contribution to the group's effort. Thus, the introductory section acquaints the reader with basic concepts of accelerators in general, then briefly describes major physical aspects of the Stanford Linear Accelerator. Only then is his attention directed to the klystron, with its auxiliary systems, and the rudiments of klystron tube performance checks. It is presumed that the reader is acquainted with basic principles of electronics and scientific notation. However, to preserve the integrity of an indoctrination guide, tedious technical discussions and mathematical analysis have been studiously avoided. It is hoped that the new operator will continue to use the text for reference long after his indoctrination period is completed. Even the more experienced operator should find that particular sections will refresh his understanding of basic principles of klystron testing.
Petitjean, Patrick; Wang, F. Y.; Wu, X. F.; Wei, J. J.
2016-12-01
Gamma-ray bursts (GRBs) are short and intense flashes at the cosmological distances, which are the most luminous explosions in the Universe. The high luminosities of GRBs make them detectable out to the edge of the visible universe. So, they are unique tools to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal evolution of the Universe. First, they can be used to constrain the history of cosmic acceleration and the evolution of dark energy in a redshift range hardly achievable by other cosmological probes. Second, long GRBs are believed to be formed by collapse of massive stars. So they can be used to derive the high-redshift star formation rate, which can not be probed by current observations. Moreover, the use of GRBs as cosmological tools could unveil the reionization history and metal evolution of the Universe, the intergalactic medium (IGM) properties and the nature of first stars in the early universe. But beyond that, the GRB high-energy photons can be applied to constrain Lorentz invariance violation (LIV) and to test Einstein's Equivalence Principle (EEP). In this paper, we review the progress on the GRB cosmology and fundamental physics probed by GRBs.
Fundamental Limits of Cooperation
Lozano, Angel; Andrews, Jeffrey G
2012-01-01
Cooperation is viewed as a key ingredient for interference management in wireless systems. This paper shows that cooperation has fundamental limitations. The main result is that even full cooperation between transmitters cannot in general change an interference-limited network to a noise-limited network. The key idea is that there exists a spectral efficiency upper bound that is independent of the transmit power. First, a spectral efficiency upper bound is established for systems that rely on pilot-assisted channel estimation; in this framework, cooperation is shown to be possible only within clusters of limited size, which are subject to out-of-cluster interference whose power scales with that of the in-cluster signals. Second, an upper bound is also shown to exist when cooperation is through noncoherent communication; thus, the spectral efficiency limitation is not a by-product of the reliance on pilot-assisted channel estimation. Consequently, existing literature that routinely assumes the high-power spect...
Revisiting energy efficiency fundamentals
Energy Technology Data Exchange (ETDEWEB)
Perez-Lombard, L.; Velazquez, D. [Grupo de Termotecnia, Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092 Seville (Spain); Ortiz, J. [Building Research Establishment (BRE), Garston, Watford, WD25 9XX (United Kingdom)
2013-05-15
Energy efficiency is a central target for energy policy and a keystone to mitigate climate change and to achieve a sustainable development. Although great efforts have been carried out during the last four decades to investigate the issue, focusing into measuring energy efficiency, understanding its trends and impacts on energy consumption and to design effective energy efficiency policies, many energy efficiency-related concepts, some methodological problems for the construction of energy efficiency indicators (EEI) and even some of the energy efficiency potential gains are often ignored or misunderstood, causing no little confusion and controversy not only for laymen but even for specialists. This paper aims to revisit, analyse and discuss some efficiency fundamental topics that could improve understanding and critical judgement of efficiency stakeholders and that could help in avoiding unfounded judgements and misleading statements. Firstly, we address the problem of measuring energy efficiency both in qualitative and quantitative terms. Secondly, main methodological problems standing in the way of the construction of EEI are discussed, and a sequence of actions is proposed to tackle them in an ordered fashion. Finally, two key topics are discussed in detail: the links between energy efficiency and energy savings, and the border between energy efficiency improvement and renewable sources promotion.
Chiral transition of fundamental and adjoint quarks
Energy Technology Data Exchange (ETDEWEB)
Capdevilla, R.M. [Instituto de Física Teórica, UNESP – Universidade Estadual Paulista, Rua Dr. Bento T. Ferraz, 271, Bloco II, 01140-070 São Paulo, SP (Brazil); Doff, A., E-mail: agomes@utfpr.edu.br [Universidade Tecnológica Federal do Paraná – UTFPR – DAFIS, Av. Monteiro Lobato Km 04, 84016-210 Ponta Grossa, PR (Brazil); Natale, A.A., E-mail: natale@ift.unesp.br [Instituto de Física Teórica, UNESP – Universidade Estadual Paulista, Rua Dr. Bento T. Ferraz, 271, Bloco II, 01140-070 São Paulo, SP (Brazil); Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil)
2014-01-20
The chiral symmetry breaking transition of quarks in the fundamental and adjoint representation is studied in a model where the gap equation contains two contributions, one containing a confining propagator and another corresponding to the exchange of one-dressed dynamically massive gluons. When quarks are in the fundamental representation the confinement effect dominates the chiral symmetry breaking while the gluon exchange is suppressed due to the dynamical gluon mass effect in the propagator and in the coupling constant. In this case the chiral and deconfinement transition temperatures are approximately the same. For quarks in the adjoint representation, due to the larger Casimir eigenvalue, the gluon exchange is operative and the chiral transition happens at a larger temperature than the deconfinement one.
TASI Lectures on the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Bousso, Raphael; Bousso, Raphael
2007-08-30
The energy density of the vacuum, Lambda, is at least 60 orders of magnitude smaller than several known contributions to it. Approaches to this problem are tightly constrained by data ranging from elementary observations to precision experiments. Absent overwhelming evidence to the contrary, dark energy can only be interpreted as vacuum energy, so the venerable assumption that Lambda=0 conflicts with observation. The possibility remains that Lambda is fundamentally variable, though constant over large spacetime regions. This can explain the observed value, but only in a theory satisfying a number of restrictive kinematic and dynamical conditions. String theory offers a concrete realization through its landscape of metastable vacua.
Possible Cosmological Implications of Time Varying Fine Structure Constant
Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.
2001-01-01
We make use of Dirac LNH and results for a time varying fine structure constant in order to derive possible laws of variation for speed of light, the number of nucleons in the Universe, energy density and gravitational constant. By comparing with experimental bounds on G variation, we find that the deceleration paramenter of the present Universe is negative. This is coherent with recent Supernovae observations.
Simple Model with Time-Varying Fine-Structure ``Constant''
Berman, M. S.
2009-10-01
Extending the original version written in colaboration with L.A. Trevisan, we study the generalisation of Dirac's LNH, so that time-variation of the fine-structure constant, due to varying electrical and magnetic permittivities is included along with other variations (cosmological and gravitational ``constants''), etc. We consider the present Universe, and also an inflationary scenario. Rotation of the Universe is a given possibility in this model.
Unity of Fundamental Interactions
Sastry, R R
2000-01-01
The vector representation of the linearized gravitational field (the graviton field) or the so called quantum gravitodynamics which describes the motion of masses in a weak gravitational field is employed to understand the unity of the four known interactions. We propose a gauge group SU(3)xSU(2)xU(1)xU(1) for such a unified field theory. In this paper we study the SU(2)xU(1)xU(1) sector of the theory and in analogy to the electroweak mixing angle we define a gravitoweak mixing angle. The unified gauge field theory predicts the existence of three massive vector bosons, the Y+/- and the X^0. and two massless vector bosons, the photon and the graviton (in its vector representation). We determine the mass spectrum of the Y+/- and the X^0 and predict a modification to the fine structure constant under unified field conditions. Furthermore, we briefly discuss the implications of the extended object formulation for the gauge hierarchy problem.
Fundamental constraints on two-time physics
Piceno, E.; Rosado, A.; Sadurní, E.
2016-10-01
We show that generalizations of classical and quantum dynamics with two times lead to a fundamentally constrained evolution. At the level of classical physics, Newton's second law is extended and exactly integrated in a (1 + 2) -dimensional space, leading to effective single-time evolution for any initial condition. The cases 2 + 2 and 3 + 2 are also analyzed. In the domain of quantum mechanics, we follow strictly the hypothesis of probability conservation by extending the Heisenberg picture to unitary evolution with two times. As a result, the observability of two temporal axes is constrained by a generalized uncertainty relation involving level spacings, total duration of the effect and Planck's constant.
Topological Quantization in Units of the Fine Structure Constant
Energy Technology Data Exchange (ETDEWEB)
Maciejko, Joseph; /Stanford U., Phys. Dept. /Stanford U., Materials Sci. Dept. /SLAC; Qi, Xiao-Liang; /Station Q, UCSB /Stanford U., Phys. Dept. /Stanford U., Materials Sci. Dept. /SLAC; Drew, H.Dennis; /Maryland U.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept. /Stanford U., Materials Sci. Dept. /SLAC
2011-11-11
Fundamental topological phenomena in condensed matter physics are associated with a quantized electromagnetic response in units of fundamental constants. Recently, it has been predicted theoretically that the time-reversal invariant topological insulator in three dimensions exhibits a topological magnetoelectric effect quantized in units of the fine structure constant {alpha} = e{sup 2}/{h_bar}c. In this Letter, we propose an optical experiment to directly measure this topological quantization phenomenon, independent of material details. Our proposal also provides a way to measure the half-quantized Hall conductances on the two surfaces of the topological insulator independently of each other.
The Interacting and Non-constant Cosmological Constant
Verma, Murli Manohar
2009-01-01
We propose a time-varying cosmological constant with a fixed equation of state, which evolves mainly through its interaction with the background during most of the long history of the universe. However, such interaction does not exist in the very early and the late-time universe and produces the acceleration during these eras when it becomes very nearly a constant. It is found that after the initial inflationary phase, the cosmological constant, that we call as lambda parameter, rolls down from a large constant value to another but very small constant value and further dominates the present epoch showing up in form of the dark energy driving the acceleration.
Institute of Scientific and Technical Information of China (English)
李林森
2011-01-01
The solutions of the equations with the variable gravitational constant are given by taking the eccentric anomaly as independent variable. The solutions include the secular and periodic variations in semi-major axis, and other orbital elements only exhibit periodic variations in the first-order solutions. The longitude of periastron and mean longitude exhibit secular variations in the second-order solutions. The numerical estimations for the case of evolution of the orbits of six binaries are given. The results are discussed and concluded.%给出了以偏近点角为自变量的变引力常数的摄动方程组的解.解包括轨道半长轴的长期和周期变化项,其他轨道根数在一阶解中无长期项,只有周期项.近星点经度和平经度在二阶解中显示长期项变化.给出了由于引力常数变化对双星轨道演变情况的数值估计,对结果做了讨论并给出结论.
Computing the dielectric constant of liquid water at constant dielectric displacement
Zhang, Chao
2015-01-01
The static dielectric constant of liquid water is computed using classical force field based molecular dynamics simulation at fixed electric displacement D. The method to constrain the electric displacement is the finite temperature classical variant of the constant-D method developed by Stengel, Spaldin and Vanderbilt (Nat. Phys. 2009, 5: 304). There is also a modification of this scheme imposing fixed values of the macroscopic field E. The method is applied to the popular SPC/E model of liquid water. We compare four different estimates of the dielectric constant, two obtained from fluctuations of the polarization at D = 0 and E = 0 and two from the variation of polarization with finite D and E. It is found that all four estimates agree when properly converged. The computational effort to achieve convergence varies however, with constant D calculations being substantially more efficient. We attribute this difference to the much shorter relaxation time of longitudinal polarization compared to transverse polar...
MID IR Optical Constants of Orthopyroxenes.
Rucks, M.; Glotch, T. D.
2014-12-01
Orthopyroxenes are common rock forming minerals that are present on many planetary bodies as well as meteorites and cosmic dust. The presence of these minerals can give implications to the petrogenic history of these planetary bodies. Optical constants, n and k, are essential inputs into radiative transfer models which are used in remote sensing techniques. [1,2] While optical constants have been determined for orthopyroxenes with high Mg content, Fe rich orthopyroxenes have not been studied as extensively. [3] The goal of this research is to determine the optical constants of orthopyroxenes ranging in composition along the enstatite-ferrosilite solid solution, to gain a more comprehensive list of these values. Specular reflectance spectra, in the range of 250-4000 cm-1, were obtained for several oriented single crystal samples at three crystallographic orientations for each sample. Optical constants, n and k, were then derived through modeling of measured spectra using the Matlab lsqcurvefit function. Preveous work has identified the optical constants for two Mg rich natural samples, enstatite and hypersthene. Current research applies the above methodology to synthetic ferrosilite, the Fe rich end-member of the orthopyroxene mineral series. Future studies will provide a more comprehensive look at the variation of n and k as a function of the Mg:Fe composition. [1] Arnold, J.A. et al (2013) (under review), [2] Glotch, T.D. and Rossman, G.R. (2009) Icarus, [3] Jäger, C. et al (1998) Astron. Astrophys.
Directory of Open Access Journals (Sweden)
F. TopsÃƒÂ¸e
2001-09-01
Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over
Fundamentals of Space Medicine
Clément, Gilles
2005-03-01
A total of more than 240 human space flights have been completed to date, involving about 450 astronauts from various countries, for a combined total presence in space of more than 70 years. The seventh long-duration expedition crew is currently in residence aboard the International Space Station, continuing a permanent presence in space that began in October 2000. During that time, investigations have been conducted on both humans and animal models to study the bone demineralization and muscle deconditioning, space motion sickness, the causes and possible treatment of postflight orthostatic intolerance, the changes in immune function, crew and crew-ground interactions, and the medical issues of living in a space environment, such as the effects of radiation or the risk of developing kidney stones. Some results of these investigations have led to fundamental discoveries about the adaptation of the human body to the space environment. Gilles Clément has been active in this research. This readable text presents the findings from the life science experiments conducted during and after space missions. Topics discussed in this book include: adaptation of sensory-motor, cardio-vascular, bone, and muscle systems to the microgravity of spaceflight; psychological and sociological issues of living in a confined, isolated, and stressful environment; operational space medicine, such as crew selection, training and in-flight health monitoring, countermeasures and support; results of space biology experiments on individual cells, plants, and animal models; and the impact of long-duration missions such as the human mission to Mars. The author also provides a detailed description of how to fly a space experiment, based on his own experience with research projects conducted onboard Salyut-7, Mir, Spacelab, and the Space Shuttle. Now is the time to look at the future of human spaceflight and what comes next. The future human exploration of Mars captures the imagination of both the
Astronomers Gain Clues About Fundamental Physics
2005-12-01
An international team of astronomers has looked at something very big -- a distant galaxy -- to study the behavior of things very small -- atoms and molecules -- to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time. The Green Bank Telescope The Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF (Click on image for GBT gallery) "The fundamental constants of physics are expected to remain fixed across space and time; that's why they're called constants! Now, however, new theoretical models for the basic structure of matter indicate that they may change. We're testing these predictions." said Nissim Kanekar, an astronomer at the National Radio Astronomy Observatory (NRAO), in Socorro, New Mexico. So far, the scientists' measurements show no change in the constants. "We've put the most stringent limits yet on some changes in these constants, but that's not the end of the story," said Christopher Carilli, another NRAO astronomer. "This is the exciting frontier where astronomy meets particle physics," Carilli explained. The research can help answer fundamental questions about whether the basic components of matter are tiny particles or tiny vibrating strings, how many dimensions the Universe has, and the nature of "dark energy." The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant. These values, considered fundamental physical constants, once were "taken as time independent, with values given once and forever" said German particle physicist Christof Wetterich. However, Wetterich explained, "the viewpoint of modern particle theory has changed in recent years," with ideas such as
Fundamental formulation for frictional contact with graded materials
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
In the paper, we develop the fundamental solutions for a graded half-plane subjected to concentrated forces acting perpendicularly and parallel to the surface. In the solutions, Young’s modulus is assumed to vary in the form of E(y)=E0eαy and Poisson’s ratio is assumed to be constant. On the basis of the fundamental solutions, the singular integral equations are formulated for the unknown traction distributions with Green’s function method. From the fundamental integral equations, a series of integral equat...
Fundamental properties of solar-like oscillating stars from frequencies of minimum $\\Delta \
Yıldız, M; Kayhan, C
2015-01-01
The large separations between the oscillation frequencies of solar-like stars are measures of stellar mean density. The separations have been thought to be mostly constant in the observed range of frequencies. However, detailed investigation shows that they are not constant, and their variations are not random but have very strong diagnostic potential for our understanding of stellar structure and evolution. In this regard, frequencies of the minimum large separation are very useful tools. From these frequencies, in addition to the large separation and frequency of maximum amplitude, Y\\i ld\\i z et al. recently have developed new methods to find almost all the fundamental stellar properties. In the present study, we aim to find metallicity and helium abundances from the frequencies, and generalize the relations given by Y\\i ld\\i z et al. for a wider stellar mass range and arbitrary metallicity ($Z$) and helium abundance ($Y$). We show that the effect of metallicity is { significant} for most of the fundamental...
Communication technology update and fundamentals
Grant, August E
2010-01-01
New communication technologies are being introduced at an astonishing rate. Making sense of these technologies is increasingly difficult. Communication Technology Update and Fundamentals is the single best source for the latest developments, trends, and issues in communication technology. Featuring the fundamental framework along with the history and background of communication technologies, Communication Technology Update and Fundamentals, 12th edition helps you stay ahead of these ever-changing and emerging technologies.As always, every chapter ha
Laser-fundamentals and applications
Energy Technology Data Exchange (ETDEWEB)
Schinagl, W.
1982-09-01
The survey article gives an introduction to laser technology. Fundamentals and physical aspects are discussed at large. After a brief historical review and a discussion of the physical fundamentals, important types of laser, characteristics of laser radiation and its applications in medicine are discussed.
Huang, Xinchuan; Taylor, Peter R.; Lee, Timothy J.
2011-01-01
High levels of theory have been used to compute quartic force fields (QFFs) for the cyclic and linear forms of the C H + molecular cation, referred to as c-C H + and I-C H +. Specifically the 33 3333 singles and doubles coupled-cluster method that includes a perturbational estimate of connected triple excitations, CCSD(T), has been used in conjunction with extrapolation to the one-particle basis set limit and corrections for scalar relativity and core correlation have been included. The QFFs have been used to compute highly accurate fundamental vibrational frequencies and other spectroscopic constants using both vibrational 2nd-order perturbation theory and variational methods to solve the nuclear Schroedinger equation. Agreement between our best computed fundamental vibrational frequencies and recent infrared photodissociation experiments is reasonable for most bands, but there are a few exceptions. Possible sources for the discrepancies are discussed. We determine the energy difference between the cyclic and linear forms of C H +, 33 obtaining 27.9 kcal/mol at 0 K, which should be the most reliable available. It is expected that the fundamental vibrational frequencies and spectroscopic constants presented here for c-C H + 33 and I-C H + are the most reliable available for the free gas-phase species and it is hoped that 33 these will be useful in the assignment of future high-resolution laboratory experiments or astronomical observations.
Mass anomalous dimension in SU(2) with six fundamental fermions
DEFF Research Database (Denmark)
Bursa, Francis; Del Debbio, Luigi; Keegan, Liam;
2010-01-01
We simulate SU(2) gauge theory with six massless fundamental Dirac fermions. We measure the running of the coupling and the mass in the Schroedinger Functional scheme. We observe very slow running of the coupling constant. We measure the mass anomalous dimension gamma, and find it is between 0.13...
The Fundamental Scale of Descriptions
Febres, Gerardo
2014-01-01
The complexity of a system description is a function of the entropy of its symbolic description. Prior to computing the entropy of the system description, an observation scale has to be assumed. In natural language texts, typical scales are binary, characters, and words. However, considering languages as structures built around certain preconceived set of symbols, like words or characters, is only a presumption. This study depicts the notion of the Description Fundamental Scale as a set of symbols which serves to analyze the essence a language structure. The concept of Fundamental Scale is tested using English and MIDI music texts by means of an algorithm developed to search for a set of symbols, which minimizes the system observed entropy, and therefore best expresses the fundamental scale of the language employed. Test results show that it is possible to find the Fundamental Scale of some languages. The concept of Fundamental Scale, and the method for its determination, emerges as an interesting tool to fac...
The Elastic Constants for Wrought Aluminum Alloys
Templin, R L; Hartmann, E C
1945-01-01
There are several constants which have been devised as numerical representations of the behavior of metals under the action of loadings which stress the metal within the range of elastic action. Some of these constants, such as Young's modulus of elasticity in tension and compression, shearing modulus of elasticity, and Poisson's ratio, are regularly used in engineering calculations. Precise tests and experience indicate that these elastic constants are practically unaffected by many of the factors which influence the other mechanical properties of materials and that a few careful determinations under properly controlled conditions are more useful and reliable than many determinations made under less favorable conditions. It is the purpose of this paper to outline the methods employed by the Aluminum Research Laboratories for the determination of some of these elastic constants, to list the values that have been determined for some of the wrought aluminum alloys, and to indicate the variations in the values that may be expected for some of the commercial products of these alloys.
Generalized Methods and Solvers for Noise Removal from Piecewise Constant Signals
Little, Max A
2010-01-01
Removing noise from piecewise constant (PWC) signals, is a challenging signal processing problem arising in many practical contexts. For example, in exploration geosciences, noisy drill hole records need separating into stratigraphic zones, and in biophysics, jumps between molecular dwell states need extracting from noisy fluorescence microscopy signals. Many PWC denoising methods exist, including total variation regularization, mean shift clustering, stepwise jump placement, running medians, convex clustering shrinkage and bilateral filtering; conventional linear signal processing methods are fundamentally unsuited however. This paper shows that most of these methods are associated with a special case of a generalized functional, minimized to achieve PWC denoising. The minimizer can be obtained by diverse solver algorithms, including stepwise jump placement, convex programming, finite differences, iterated running medians, least angle regression, regularization path following, and coordinate descent. We intr...
The finite element method its basis and fundamentals
Zienkiewicz, Olek C; Zhu, JZ
2013-01-01
The Finite Element Method: Its Basis and Fundamentals offers a complete introduction to the basis of the finite element method, covering fundamental theory and worked examples in the detail required for readers to apply the knowledge to their own engineering problems and understand more advanced applications. This edition sees a significant rearrangement of the book's content to enable clearer development of the finite element method, with major new chapters and sections added to cover: Weak forms Variational forms Multi-dimensional field prob
Spectrophotometric determination of association constant
DEFF Research Database (Denmark)
2016-01-01
Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charg...
Constant-Pressure Hydraulic Pump
Galloway, C. W.
1982-01-01
Constant output pressure in gas-driven hydraulic pump would be assured in new design for gas-to-hydraulic power converter. With a force-multiplying ring attached to gas piston, expanding gas would apply constant force on hydraulic piston even though gas pressure drops. As a result, pressure of hydraulic fluid remains steady, and power output of the pump does not vary.
Spectrophotometric determination of association constant
DEFF Research Database (Denmark)
Spanget-Larsen, Jens
2016-01-01
Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charge...
Fundamental principles of heat transfer
Whitaker, Stephen
1977-01-01
Fundamental Principles of Heat Transfer introduces the fundamental concepts of heat transfer: conduction, convection, and radiation. It presents theoretical developments and example and design problems and illustrates the practical applications of fundamental principles. The chapters in this book cover various topics such as one-dimensional and transient heat conduction, energy and turbulent transport, forced convection, thermal radiation, and radiant energy exchange. There are example problems and solutions at the end of every chapter dealing with design problems. This book is a valuable int
Fundamentals of technology project management
Garton, Colleen
2012-01-01
Designed to provide software engineers, students, and IT professionals with an understanding of the fundamentals of project management in the technology/IT field, this book serves as a practical introduction to the subject. Updated with information on how Fundamentals of Project Management integrates with and complements Project Management Institute''s Project Management Body of Knowledge, this collection explains fundamental methodologies and techniques while also discussing new technology, tools, and virtual work environments. Examples and case studies are based on technology projects, and t
Nagy, Peter B; Simonetti, Francesco; Instanes, Geir
2014-09-01
Recent improvements in tomographic reconstruction techniques generated a renewed interest in short-range ultrasonic guided wave inspection for real-time monitoring of internal corrosion and erosion in pipes and other plate-like structures. Emerging evidence suggests that in most cases the fundamental asymmetric A0 mode holds a distinct advantage over the earlier market leader fundamental symmetric S0 mode. Most existing A0 mode inspections operate at relatively low inspection frequencies where the mode is highly dispersive therefore very sensitive to variations in wall thickness. This paper examines the potential advantages of increasing the inspection frequency to the so-called constant group velocity (CGV) point where the group velocity remains essentially constant over a wide range of wall thickness variation, but the phase velocity is still dispersive enough to allow accurate wall thickness assessment from phase angle measurements. This paper shows that in the CGV region the crucial issue of temperature correction becomes especially simple, which is particularly beneficial when higher-order helical modes are also exploited for tomography. One disadvantage of working at such relatively high inspection frequency is that, as the slower A0 mode becomes faster and less dispersive, the competing faster S0 mode becomes slower and more dispersive. At higher inspection frequencies these modes cannot be separated any longer based on their vibration polarization only, which is mostly tangential for the S0 mode while mostly normal for the A0 at low frequencies, as the two modes become more similar as the frequency increases. Therefore, we propose a novel method for suppressing the unwanted S0 mode based on the Poisson effect of the material by optimizing the angle of inclination of the equivalent transduction force of the Electromagnetic Acoustic Transducers (EMATs) used for generation and detection purposes.
Fundamental approach to discrete mathematics
Acharjya, DP
2005-01-01
Salient Features Mathematical logic, fundamental concepts, proofs and mathematical induction (Chapter 1) Set theory, fundamental concepts, theorems, proofs, Venn diagrams, product of sets, application of set theory and fundamental products (Chapter 2) An introduction to binary relations and concepts, graphs, arrow diagrams, relation matrix, composition of relations, types of relation, partial order relations, total order relation, closure of relations, poset, equivalence classes and partitions. (Chapter 3) An introduction to functions and basic concepts, graphs, composition of functions, floor and ceiling function, characteristic function, remainder function, signum function and introduction to hash function. (Chapter 4) The algebraic structure includes group theory and ring theory. Group theory includes group, subgroups, cyclic group, cosets, homomorphism, introduction to codes and group codes and error correction for block code. The ring theory includes general definition, fundamental concepts, integra...
Clinical fundamentals for radiation oncologists.
Yang, Jack
2011-11-01
Clinical fundamentals for radiation oncologists. Hasan Murshed. Medical Physics Publishing, Madison, WI, 2011. 680 pp. (soft cover), Price: $90.00. 978-1-930524-43-9. © 2011 American Association of Physicists in Medicine.
Quantum mechanics I the fundamentals
Rajasekar, S
2015-01-01
Quantum Mechanics I: The Fundamentals provides a graduate-level account of the behavior of matter and energy at the molecular, atomic, nuclear, and sub-nuclear levels. It covers basic concepts, mathematical formalism, and applications to physically important systems.
Fundamentals of modern unsteady aerodynamics
Gülçat, Ülgen
2010-01-01
This introduction to the principles of unsteady aerodynamics covers all the core concepts, provides readers with a review of the fundamental physics, terminology and basic equations, and covers hot new topics such as the use of flapping wings for propulsion.
When is the growth index constant?
Polarski, David; Starobinsky, Alexei A.; Giacomini, Hector
2016-12-01
The growth index γ is an interesting tool to assess the phenomenology of dark energy (DE) models, in particular of those beyond general relativity (GR). We investigate the possibility for DE models to allow for a constant γ during the entire matter and DE dominated stages. It is shown that if DE is described by quintessence (a scalar field minimally coupled to gravity), this behaviour of γ is excluded either because it would require a transition to a phantom behaviour at some finite moment of time, or, in the case of tracking DE at the matter dominated stage, because the relative matter density Ωm appears to be too small. An infinite number of solutions, with Ωm and γ both constant, are found with wDE = 0 corresponding to Einstein-de Sitter universes. For all modified gravity DE models satisfying Geff >= G, among them the f(R) DE models suggested in the literature, the condition to have a constant wDE is strongly violated at the present epoch. In contrast, DE tracking dust-like matter deep in the matter era, but with Ωm G and an example is given using scalar-tensor gravity for a range of admissible values of γ. For constant wDE inside GR, departure from a quasi-constant value is limited until today. Even a large variation of wDE may not result in a clear signature in the change of γ. The change however is substantial in the future and the asymptotic value of γ is found while its slope with respect to Ωm (and with respect to z) diverges and tends to ‑∞.
Conjugated polyelectrolytes fundamentals and applications
Liu, Bin
2013-01-01
This is the first monograph to specifically focus on fundamentals and applications of polyelectrolytes, a class of molecules that gained substantial interest due to their unique combination of properties. Combining both features of organic semiconductors and polyelectrolytes, they offer a broad field for fundamental research as well as applications to analytical chemistry, optical imaging, and opto-electronic devices. The initial chapters introduce readers to the synthesis, optical and electrical properties of various conjugated polyelectrolytes. This is followed by chapters on the applica
Fundamentals of electronic image processing
Weeks, Arthur R
1996-01-01
This book is directed to practicing engineers and scientists who need to understand the fundamentals of image processing theory and algorithms to perform their technical tasks. It is intended to fill the gap between existing high-level texts dedicated to specialists in the field and the need for a more practical, fundamental text on image processing. A variety of example images are used to enhance reader understanding of how particular image processing algorithms work.
Open Source Fundamental Industry Classification
Kakushadze, Zura; Yu, Willie
2017-01-01
We provide complete source code for building a fundamental industry classification based on publically available and freely downloadable data. We compare various fundamental industry classifications by running a horserace of short-horizon trading signals (alphas) utilizing open source heterotic risk models (https://ssrn.com/abstract=2600798) built using such industry classifications. Our source code includes various stand-alone and portable modules, e.g., for downloading/parsing web data, etc.
Expected Devaluation and Economic Fundamentals
Alun H. Thomas
1993-01-01
Recent incidents of exchange rate collapse have provoked interest in the extent to which such events are determined by economic fundamentals. This paper considers whether interest rate differentials are appropriate measures of the risk of devaluation and whether this measure of devaluation risk reflects the movements of variables which capture internal and external balance. The paper finds that interest rate differentials reflect devaluation risk but that movements in fundamental variables ha...
Hydrogenlike highly charged ions for tests of the time independence of fundamental constants.
Schiller, S
2007-05-04
Hyperfine transitions in the electronic ground state of cold, trapped hydrogenlike highly charged ions have attractive features for use as frequency standards because the majority of systematic frequency shifts are smaller by orders of magnitude compared to many microwave and optical frequency standards. Frequency measurements of these transitions hold promise for significantly improved laboratory tests of local position invariance of the electron and quark masses.
Quast, R; Smette, A; Garcet, O; Ledoux, C; López, S; Wisotzki, L
2004-01-01
Spectroscopy of QSO absorption lines provides essential observational input for the study of nucleosynthesis and chemical evolution of galaxies at high redshift. But new observations may indicate that present chemical abundance data are biased due to deficient spectral resolution and unknown selection effects: Recent high-resolution spectra reveal the hitherto unperceived chemical nonuniformity of molecular hydrogen-bearing damped Lyman-alpha (DLA) systems, and the novel H/ESO DLA survey produces compelling evidence for faint QSOs being attenuated by dust. We present a revised analysis of the molecular hydrogen-bearing DLA complex toward HE 0515-4414 showing nonuniform differential depletion of chemical elements onto dust grains, and introduce to the H/ESO DLA survey and its implications. Conclusively, we aim at starting an unbiased chemical abundance database established on high-resolution spectroscopic observations. New data to probe the temperature-redshift relation predicted by standard cosmology and to t...
Energy Technology Data Exchange (ETDEWEB)
Mount, Brianna J. [Florida State University, Department of Physics (United States); Redshaw, Matthew [National Superconducting Cyclotron Laboratory (United States); Myers, Edmund G., E-mail: myers@nucmar.physics.fsu.edu [Florida State University, Department of Physics (United States)
2011-07-15
We present a summary of precision atomic mass measurements of stable isotopes carried out at Florida State University. These include the alkalis {sup 6}Li, {sup 23}Na, {sup 39,41}K, {sup 85,87}Rb, {sup 133}Cs; the rare gas isotopes {sup 84,86}Kr and {sup 129,130,132,136}Xe; {sup 17,18}O, {sup 19}F, {sup 28}Si, {sup 31}P, {sup 32}S; and various isotope pairs of importance to neutrino physics, namely {sup 74,76}Se/{sup 74,76}Ge, {sup 130}Xe/{sup 130}Te, and {sup 115}In/{sup 115}Sn. We also summarize our Penning trap measurements of the dipole moments of PH{sup + } and HCO{sup + }.
DETERMINATION OF STABILITY CONSTANTS OF MANGANESE (II ...
African Journals Online (AJOL)
DR. AMINU
Keywords: Amino acids, dissociation constant, potentiometry, stability constant. INTRODUCTION ... constants of manganese (II) amino acid complexes using potentiometer. .... Principles of Biochemistry Third Edition,. Worth publishers, 41 ...
The Astronomical Reach of Fundamental Physics
Burrows, Adam
2014-01-01
Using basic physical arguments, we derive by dimensional and physical analysis the characteristic masses and sizes of important objects in the Universe in terms of just a few fundamental constants. This exercise illustrates the unifying power of physics and the profound connections between the small and the large in the Cosmos we inhabit. We focus on the minimum and maximum masses of normal stars, the corresponding quantities for neutron stars, the maximum mass of a rocky planet, the maximum mass of a white dwarf, and the mass of a typical galaxy. To zeroth order, we show that all these masses can be expressed in terms of either the Planck mass or the Chandrasekar mass, in combination with various dimensionless quantities. With these examples we expose the deep interrelationships imposed by Nature between disparate realms of the Universe and the amazing consequences of the unifying character of physical law.
Ruzsa's Constant on Additive Functions
Institute of Scientific and Technical Information of China (English)
Jin Hui FANG; Yong Gao CHEN
2013-01-01
A function f:N → R is called additive if f(mn) =f(m)+f(n) for all m,n with (m,n) =1.Let μ(x) =maxn≤x(f(n)-f(n + 1)) and v(x) =maxn≤x(f(n + 1)-f(n)).In 1979,Ruzsa proved that there exists a constant c such that for any additive function f,μ(x) ≤ cv(x2) + cf,where cf is a constant depending only on f.Denote by Raf the least such constant c.We call Raf Ruzsa's constant on additive functions.In this paper,we prove that Raf ≤ 20.
Naturally Time Dependent Cosmological Constant
Gregori, A
2004-01-01
In the light of the proposal of hep-th/0207195, we discuss in detail the issue of the cosmological constant, explaining how can string theory naturally predict the value which is experimentally observed, without low-energy supersymmetry.
2-harmonic Submanifolds in a Quasi Constant Holomorphic Sectional Curvature Space
Institute of Scientific and Technical Information of China (English)
ZHU Jing-yong; SONG Wei-dong
2013-01-01
In the present paper,the authors study totally real 2-harmonic submanifolds in a quasi constant holomorphic sectional curvature space and obtain a Simons' type integral inequality of compact submanifolds as well as some pinching theoremsonthe second fundamental form.
Inflation and the cosmological constant
Directory of Open Access Journals (Sweden)
FENG Chaojun
2014-08-01
Full Text Available By assuming the cosmological “constant” is no longer a constant during the inflation epoch,it is found that the cosmological constant fine-tuning problem is solved.In the meanwhile,inflation models could predict a large tensor-to-scalar ratio,correct power spectral index and a larger running of it.Furthermore,the e-folding number is large enough to overcome the horizon,flatness problems in the Big Bang cosmology.
Analytical fundamentals of migration in reflection seismics
Directory of Open Access Journals (Sweden)
Ray Arnab K.
2016-06-01
Full Text Available We consider migration in reflection seismics from a completely analytical perspective. We review the basic geometrical ray-path approach to understanding the subject of migration, and discuss the limitations of this method. We stress the importance of the linear differential wave equation in migration. We also review briefly how a wavefield, travelling with a constant velocity, is extrapolated from the differential wave equation, with the aid of Fourier transforms. Then we present a non-numerical treatment by which we derive an asymptotic solution for both the amplitude and the phase of a planar subsurface wavefield that has a vertical velocity variation. This treatment entails the application of the Wentzel-Kramers-Brillouin approximation, whose self-consistency can be established due to a very slow logarithmic variation of the velocity in the vertical direction, a feature that holds more firmly at increasingly greater subsurface depths. For a planar subsurface wavefield, we also demonstrate an equivalence between two apparently different migration algorithms, namely, the constant-velocity Stolt Migration algorithm and the stationary-phase approximation method.
Variational transition state theory
Energy Technology Data Exchange (ETDEWEB)
Truhlar, D.G. [Univ. of Minnesota, Minneapolis (United States)
1993-12-01
This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.
Dependence of rate constants on vibrational temperatures - An Arrhenius description
Ford, D. I.; Johnson, R. E.
1988-01-01
An interpretation of the variation of rate constants with vibrational temperature is proposed which introduces parameters analogous to those of the classical Arrhenius expression. The constancy of vibrational activation energy is studied for the dissociaton of NO, the ion-molecular reaction of O(+) with N2, and the atom exchange reaction of I with H2. It is found that when a Boltzmann distribution for vibrational states is applicable, the variation of the rate constant with the vibrational temperature can be used to define a vibrational activation energy. The method has application to exchange reactions where a vibrational energy threshold exists.
Learning Read-constant Polynomials of Constant Degree modulo Composites
DEFF Research Database (Denmark)
Chattopadhyay, Arkadev; Gavaldá, Richard; Hansen, Kristoffer Arnsfelt;
2011-01-01
Boolean functions that have constant degree polynomial representation over a fixed finite ring form a natural and strict subclass of the complexity class \\textACC0ACC0. They are also precisely the functions computable efficiently by programs over fixed and finite nilpotent groups. This class...... is not known to be learnable in any reasonable learning model. In this paper, we provide a deterministic polynomial time algorithm for learning Boolean functions represented by polynomials of constant degree over arbitrary finite rings from membership queries, with the additional constraint that each variable...
Effective cosmological constant induced by stochastic fluctuations of Newton's constant
de Cesare, Marco; Lizzi, Fedele; Sakellariadou, Mairi
2016-09-01
We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.
Effective cosmological constant induced by stochastic fluctuations of Newton's constant
de Cesare, Marco; Sakellariadou, Mairi
2016-01-01
We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.
Fundamental tests of nature with cooled and stored exotic ions
CERN. Geneva
2014-01-01
The presentation will concentrate on recent applications with exciting results of Penning traps in atomic and nuclear physics with cooled and stored exotic ions. These are high-accuracy mass measurements of short-lived radionuclides, g-factor determinations of the bound-electron in highly-charged, hydrogen-like ions and g-factor measurements of the proton and antiproton. The experiments are dedicated, e.g., to astrophysics studies and to tests of fundamental symmetries in the case of mass measurements on radionuclides, and to the determination of fundamental constants and a CPT test in the case of the g-factor measurements.
Astrophysical probes of fundamental physics
Energy Technology Data Exchange (ETDEWEB)
Martins, C.J.A.P. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); DAMTP, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2009-10-15
I review the motivation for varying fundamental couplings and discuss how these measurements can be used to constrain fundamental physics scenarios that would otherwise be inaccessible to experiment. I highlight the current controversial evidence for varying couplings and present some new results. Finally I focus on the relation between varying couplings and dark energy, and explain how varying coupling measurements might be used to probe the nature of dark energy, with some advantages over standard methods. In particular I discuss what can be achieved with future spectrographs such as ESPRESSO and CODEX.
The fundamentals of mathematical analysis
Fikhtengol'ts, G M
1965-01-01
The Fundamentals of Mathematical Analysis, Volume 1 is a textbook that provides a systematic and rigorous treatment of the fundamentals of mathematical analysis. Emphasis is placed on the concept of limit which plays a principal role in mathematical analysis. Examples of the application of mathematical analysis to geometry, mechanics, physics, and engineering are given. This volume is comprised of 14 chapters and begins with a discussion on real numbers, their properties and applications, and arithmetical operations over real numbers. The reader is then introduced to the concept of function, i
RFID design fundamentals and applications
Lozano-Nieto, Albert
2010-01-01
RFID is an increasingly pervasive tool that is now used in a wide range of fields. It is employed to substantiate adherence to food preservation and safety standards, combat the circulation of counterfeit pharmaceuticals, and verify authenticity and history of critical parts used in aircraft and other machinery-and these are just a few of its uses. Goes beyond deployment, focusing on exactly how RFID actually worksRFID Design Fundamentals and Applications systematically explores the fundamental principles involved in the design and characterization of RFID technologies. The RFID market is expl
Fundamentals of multicore software development
Pankratius, Victor; Tichy, Walter F
2011-01-01
With multicore processors now in every computer, server, and embedded device, the need for cost-effective, reliable parallel software has never been greater. By explaining key aspects of multicore programming, Fundamentals of Multicore Software Development helps software engineers understand parallel programming and master the multicore challenge. Accessible to newcomers to the field, the book captures the state of the art of multicore programming in computer science. It covers the fundamentals of multicore hardware, parallel design patterns, and parallel programming in C++, .NET, and Java. It
Fundamental Research and Developing Countries
Narison, Stéphan
2002-01-01
In the first part of this report, I discuss the sociological role of fundamental research in Developing Countries (DC) and how to realize this program. In the second part, I give a brief and elementary introduction to the field of high-energy physics (HEP), accessible to a large audience not necessary physicists. The aim of this report is to make politicians and financial backers aware on the long-term usefulness of fundamental research in DC and on the possible globalisation of HEP and, in general, of science.
Fundamental approach to discrete mathematics
Acharjya, DP
2009-01-01
About the Book: The book `Fundamental Approach to Discrete Mathematics` is a required part of pursuing a computer science degree at most universities. It provides in-depth knowledge to the subject for beginners and stimulates further interest in the topic. The salient features of this book include: Strong coverage of key topics involving recurrence relation, combinatorics, Boolean algebra, graph theory and fuzzy set theory. Algorithms and examples integrated throughout the book to bring clarity to the fundamental concepts. Each concept and definition is followed by thoughtful examples.
Critique of Coleman's Theory of the Vanishing Cosmological Constant
Susskind, Leonard
In these lectures I would like to review some of the criticisms to the Coleman worm-hole theory of the vanishing cosmological constant. In particular, I would like to focus on the most fundamental assumption that the path integral over topologies defines a probability for the cosmological constant which has the form EXP(A) with A being the Baum-Hawking-Coleman saddle point. Coleman argues that the euclideam path integral over all geometries may be dominated by special configurations which consist of large smooth "spheres" connected by any number of narrow wormholes. Formally summing up such configurations gives a very divergent expression for the path integral…
Einstein Manifolds, Abelian Instantons, Bundle Reduction, and the Cosmological Constant
Soo, C P
2001-01-01
The anti-self-dual projection of the spin connections of certain four-dimensional Einstein manifolds can be Abelian in nature. These configurations signify bundle reductions. By a theorem of Kobayashi and Nomizu such a process is predicated on the existence of a covariantly constant field. It turns out that even without fundamental Higgs fields and other physical matter, gravitational self-interactions can generate this mechanism if the cosmological constant is non-vanishing. This article identifies the order parameter, and clarifies how these Abelian instanton solutions are associated with a Higgs triplet which causes the bundle reduction from SO(3) gauge group to U(1).
Mirror QCD and Cosmological Constant
Pasechnik, Roman; Teryaev, Oleg
2016-01-01
An analog of Quantum Chromo Dynamics (QCD) sector known as mirror QCD (mQCD) can affect the cosmological evolution and help in resolving the Cosmological Constant problem. In this work, we explore an intriguing possibility for a compensation of the negative QCD vacuum contribution to the ground state energy density of the universe by means of a positive contribution from the chromomagnetic gluon condensate in mQCD. The trace anomaly compensation condition and the form of the mQCD coupling constant in the infrared limit have been proposed by analysing a partial non-perturbative solution of the Einstein--Yang-Mills equations of motion.
Bouncing universes with varying constants
Energy Technology Data Exchange (ETDEWEB)
Barrow, John D [DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Kimberly, Dagny [Theoretical Physics, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom); Magueijo, Joao [Theoretical Physics, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom)
2004-09-21
We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying alpha theory leads to a bouncing universe. The value of alpha increases monotonically, remaining approximately constant during most of each cycle, but increasing significantly around each bounce. When dissipation is introduced we show that in each new cycle the universe expands for longer and to a larger size. We find a similar effect for closed bouncing universes in Brans-Dicke theory, where G also varies monotonically in time from cycle to cycle. Similar behaviour occurs also in varying speed of light theories.
Bouncing Universes with Varying Constants
Barrow, J D; Magueijo, J; Barrow, John D.; Kimberly, Dagny; Magueijo, Joao
2004-01-01
We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying-alpha theory leads to a bouncing universe. The value of alpha increases monotonically, remaining approximately constant during most of each cycle, but increasing significantly around each bounce. When dissipation is introduced we show that in each new cycle the universe expands for longer and to a larger size. We find a similar effect for closed bouncing universes in Brans-Dicke theory, where $G$ also varies monotonically in time from cycle to cycle. Similar behaviour occurs also in varying speed of light theories.
Gravitational Instantons and Cosmological Constant
Cyriac, Josily
2015-01-01
The cosmological dynamics of an otherwise empty universe in the presence of vacuum fields is considered. Quantum fluctuations at the Planck scale leads to a dynamical topology of space-time at very small length scales, which is dominated by compact gravitational instantons. The Planck scale vacuum energy acts as a source for the curvature of the these compact gravitational instantons and decouples from the large scale energy momentum tensor of the universe, thus making the observable cosmological constant vanish. However, a Euclidean functional integral over all possible topologies of the gravitational instantons generates a small non-zero value for the large scale cosmological constant, which agrees with the present observations.
Fundamentals: IVC and Computer Science
Gozalvez, Javier; Haerri, Jerome; Hartenstein, Hannes; Heijenk, Gerhard J.; Kargl, Frank; Petit, Jonathan; Scheuermann, Björn; Tieler, Tessa; Altintas, O.; Dressler, F.; Hartenstein, H.; Tonguz, O.K.
The working group on “Fundamentals: IVC and Computer Science‿ discussed the lasting value of achieved research results as well as potential future directions in the field of inter- vehicular communication. Two major themes ‘with variations’ were the dependence on a specific technology (particularly
Fundamentals: IVC and Computer Science
Gozalvez, Javier; Haerri, Jerome; Hartenstein, Hannes; Heijenk, Gerhard J.; Kargl, Frank; Petit, Jonathan; Scheuermann, Björn; Tieler, Tessa; Altintas, O.; Dressler, F.; Hartenstein, H.; Tonguz, O.K.
2013-01-01
The working group on “Fundamentals: IVC and Computer Science‿ discussed the lasting value of achieved research results as well as potential future directions in the field of inter- vehicular communication. Two major themes ‘with variations’ were the dependence on a specific technology (particularly
Brake Fundamentals. Automotive Articulation Project.
Cunningham, Larry; And Others
Designed for secondary and postsecondary auto mechanics programs, this curriculum guide contains learning exercises in seven areas: (1) brake fundamentals; (2) brake lines, fluid, and hoses; (3) drum brakes; (4) disc brake system and service; (5) master cylinder, power boost, and control valves; (6) parking brakes; and (7) trouble shooting. Each…
Calorimetry fundamentals, instrumentation and applications
Sarge, Stefan M; Hemminger, Wolfgang
2014-01-01
Clearly divided into three parts, this practical book begins by dealing with all fundamental aspects of calorimetry. The second part looks at the equipment used and new developments. The third and final section provides measurement guidelines in order to obtain the best results. The result is optimized knowledge for users of this technique, supplemented with practical tips and tricks.
van Doesum, A.; van Kesteren, H.W.M.; van Norden, G.J.
2016-01-01
Fundamentals of EU VAT Law aims at providing a deep insight into the systematics, the functioning and the principles of the European Value Added Tax (VAT) system. VAT is responsible for generating approximately EUR 903 billion per year in tax revenues across the European Union – revenues that play a
Fundamentals of Microelectronics Processing (VLSI).
Takoudis, Christos G.
1987-01-01
Describes a 15-week course in the fundamentals of microelectronics processing in chemical engineering, which emphasizes the use of very large scale integration (VLSI). Provides a listing of the topics covered in the course outline, along with a sample of some of the final projects done by students. (TW)
Fundamentals of Welding. Teacher Edition.
Fortney, Clarence; And Others
These instructional materials assist teachers in improving instruction on the fundamentals of welding. The following introductory information is included: use of this publication; competency profile; instructional/task analysis; related academic and workplace skills list; tools, materials, and equipment list; and 27 references. Seven units of…
Status of Fundamental Physics Program
Lee, Mark C.
2003-01-01
Update of the Fundamental Physics Program. JEM/EF Slip. 2 years delay. Reduced budget. Community support and advocacy led by Professor Nick Bigelow. Reprogramming led by Fred O Callaghan/JPL team. LTMPF M1 mission (DYNAMX and SUMO). PARCS. Carrier re baselined on JEM/EF.
Different Variants of Fundamental Portfolio
Directory of Open Access Journals (Sweden)
Tarczyński Waldemar
2014-06-01
Full Text Available The paper proposes the fundamental portfolio of securities. This portfolio is an alternative for the classic Markowitz model, which combines fundamental analysis with portfolio analysis. The method’s main idea is based on the use of the TMAI1 synthetic measure and, in limiting conditions, the use of risk and the portfolio’s rate of return in the objective function. Different variants of fundamental portfolio have been considered under an empirical study. The effectiveness of the proposed solutions has been related to the classic portfolio constructed with the help of the Markowitz model and the WIG20 market index’s rate of return. All portfolios were constructed with data on rates of return for 2005. Their effectiveness in 2006- 2013 was then evaluated. The studied period comprises the end of the bull market, the 2007-2009 crisis, the 2010 bull market and the 2011 crisis. This allows for the evaluation of the solutions’ flexibility in various extreme situations. For the construction of the fundamental portfolio’s objective function and the TMAI, the study made use of financial and economic data on selected indicators retrieved from Notoria Serwis for 2005.
Fundamental stellar properties from asteroseismology
DEFF Research Database (Denmark)
Silva Aguirre, V.; Casagrande, L.; Miglio, A.
2013-01-01
Accurate characterization of stellar populations is of prime importance to correctly understand the formation and evolution process of our Galaxy. The field of asteroseismology has been particularly successful in such an endeavor providing fundamental parameters for large samples of stars in diff...
Fundamentals of Biomass pellet production
DEFF Research Database (Denmark)
Holm, Jens Kai; Henriksen, Ulrik Birk; Hustad, Johan Einar
2005-01-01
Pelletizing experiments along with modelling of the pelletizing process have been carried out with the aim of understanding the fundamental physico-chemical mechanisms that control the quality and durability of biomass pellets. A small-scale California pellet mill (25 kg/h) located with the Biomass...
Energy informatics: Fundamentals and standardization
Directory of Open Access Journals (Sweden)
Biyao Huang
2017-06-01
Full Text Available Based on international standardization and power utility practices, this paper presents a preliminary and systematic study on the field of energy informatics and analyzes boundary expansion of information and energy system, and the convergence of energy system and ICT. A comprehensive introduction of the fundamentals and standardization of energy informatics is provided, and several key open issues are identified.
Biological Computing Fundamentals and Futures
Akula, Balaji; Cusick, James
2009-01-01
The fields of computing and biology have begun to cross paths in new ways. In this paper a review of the current research in biological computing is presented. Fundamental concepts are introduced and these foundational elements are explored to discuss the possibilities of a new computing paradigm. We assume the reader to possess a basic knowledge of Biology and Computer Science
Fundamentals: IVC and computer science
Gozalvez, Javier; Haerri, Jerome; Hartenstein, Hannes; Heijenk, Geert; Kargl, Frank; Petit, Jonathan; Scheuermann, Björn; Tieler, Tessa; Altintas, O.; Dressler, F.; Hartenstein, H.; Tonguz, O.K.
2013-01-01
The working group on “Fundamentals: IVC and Computer Science” discussed the lasting value of achieved research results as well as potential future directions in the field of inter- vehicular communication. Two major themes ‘with variations’ were the dependence on a specific technology (particularly
Energy Technology Data Exchange (ETDEWEB)
Krueger, E.; Nistler, W.; Weirauch, W. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)
1997-04-01
Using a special high-precision apparatus at ILL the quotient h/m{sub n} (h Planck constant, m{sub n} neutron mass) has been measured. The value measured for h/m{sub n} leads to {alpha}{sup -1} = 137.03601082(524) (relative uncertainty: 3.9{center_dot}10{sup -8}) It was the first time that this fundamental constant has been determined by means of neutrons. The experiment, which had been running since 1981 in a preliminary version and since 1987 in the final version, which was finished in December 1996, is described. (author).
Benz, Samuel; White, D. Rod; Qu, JiFeng; Rogalla, Horst; Tew, Weston
2010-01-01
Currently, the CODATA value of the Boltzmann constant is dominated by a single gas-based thermometry measurement with a relative standard uncertainty of 1.8×10−6 [P.J. Mohr, B.N. Taylor, D.B. Newell, CODATA recommended values of the fundamental physical constants: 2006, Rev. Mod. Phys. 80 (2008)
Yan, Mu-Lin; Huang, Wei; Xiao, Neng-Chao
2011-01-01
The recent OPERA experiment of superluminal neutrinos has deep consequences in cosmology. In cosmology a fundamental constant is the cosmological constant. From observations one can estimate the effective cosmological constant $\\Lambda_{eff}$ which is the sum of the quantum zero point energy $\\Lambda_{dark energy}$ and the geometric cosmological constant $\\Lambda$. The OPERA experiment can be applied to determine the geometric cosmological constant $\\Lambda$. It is the first time to distinguish the contributions of $\\Lambda$ and $\\Lambda_{dark energy}$ from each other by experiment. The determination is based on an explanation of the OPERA experiment in the framework of Special Relativity with de Sitter space-time symmetry.
Fundamental Imaging Limits of Radio Telescope Arrays
Wijnholds, Stefan J; 10.1109/JSTSP.2008.2004216
2010-01-01
The fidelity of radio astronomical images is generally assessed by practical experience, i.e. using rules of thumb, although some aspects and cases have been treated rigorously. In this paper we present a mathematical framework capable of describing the fundamental limits of radio astronomical imaging problems. Although the data model assumes a single snapshot observation, i.e. variations in time and frequency are not considered, this framework is sufficiently general to allow extension to synthesis observations. Using tools from statistical signal processing and linear algebra, we discuss the tractability of the imaging and deconvolution problem, the redistribution of noise in the map by the imaging and deconvolution process, the covariance of the image values due to propagation of calibration errors and thermal noise and the upper limit on the number of sources tractable by self calibration. The combination of covariance of the image values and the number of tractable sources determines the effective noise ...
Decay Constants of Vector Mesons
Institute of Scientific and Technical Information of China (English)
LI Heng-Mei; WAN Shao-Long
2008-01-01
@@ The light vector mesons are studied within the framework of the Bethe-Salpeter equation with the vector-vectortype flat-bottom potential The Bethe-Salpeter wavefunctions and the decay constants of the vector mesons are obtained. All the obtained results, fρ, fφ, and fΚ* , are in agreement with the experimental values, respectively.
Ford, T. A.
1979-01-01
In one option for this project, the rotation-vibration infrared spectra of a number of gaseous diatomic molecules were recorded, from which the fundamental vibrational wavenumber, the force constant, the rotation-vibration interaction constant, the equilibrium rotational constant, and the equilibrium internuclear distance were determined.…
Characterization of a constant current charge detector.
Mori, Masanobu; Chen, Yongjing; Ohira, Shin-Ichi; Dasgupta, Purnendu K
2012-12-15
Ion exchangers are ionic equivalents of doped semiconductors, where cations and anions are equivalents of holes and electrons as charge carriers in solid state semiconductors. We have previously demonstrated an ion exchange membrane (IEM) based electrolyte generator which behaves similar to a light-emitting diode and a charge detector (ChD) which behaves analogous to a p-i-n photodiode. The previous work on the charge detector, operated at a constant voltage, established its unique ability to respond to the charge represented by the analyte ions regardless of their redox properties, rather than to their conductivities. It also suggested that electric field induced dissociation (EFID) of water occurs at one or both ion exchange membranes. A logical extension is to study the behavior of the same device, operated in a constant current mode (ChD(i)). The evidence indicates that in the present operational mode the device also responds to the charge represented by the analytes and not their conductivity. Injection of a base into a charge detector operated in the constant voltage mode was not previously examined; in the constant current mode, base injection appears to inhibit EFID. The effects of applied current, analyte residence time and outer channel fluid composition were individually examined; analyte ions of different mobilities as well as affinities for the respective IEMs were used. While the exact behavior is somewhat dependent on the applied current, strong electrolytes, both acids and salts, respond the highest and in a near-uniform fashion, weak acids and their salts respond in an intermediate fashion and bases produce the lowest responses. A fundamentally asymmetric behavior is observed. Injected bases but not injected acids produce a poor response; the effects of incorporating a strong base as the electrolyte in the anion exchange membrane (AEM) compartment is far greater than incorporating an acid in the cation exchange membrane (CEM) compartment. These
Mass anomalous dimension in SU(2) with six fundamental fermions
Bursa, Francis; Keegan, Liam; Pica, Claudio; Pickup, Thomas
2010-01-01
We simulate SU(2) gauge theory with six massless fundamental Dirac fermions. We measure the running of the coupling and the mass in the Schroedinger Functional scheme. We observe very slow running of the coupling constant. We measure the mass anomalous dimension gamma, and find it is between 0.135 and 1.03 in the range of couplings consistent with the existence of an IR fixed point.
The 1% concordance Hubble constant
Energy Technology Data Exchange (ETDEWEB)
Bennett, C. L.; Larson, D.; Weiland, J. L. [Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Hinshaw, G., E-mail: cbennett@jhu.edu [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)
2014-10-20
The determination of the Hubble constant has been a central goal in observational astrophysics for nearly a hundred years. Extraordinary progress has occurred in recent years on two fronts: the cosmic distance ladder measurements at low redshift and cosmic microwave background (CMB) measurements at high redshift. The CMB is used to predict the current expansion rate through a best-fit cosmological model. Complementary progress has been made with baryon acoustic oscillation (BAO) measurements at relatively low redshifts. While BAO data do not independently determine a Hubble constant, they are important for constraints on possible solutions and checks on cosmic consistency. A precise determination of the Hubble constant is of great value, but it is more important to compare the high and low redshift measurements to test our cosmological model. Significant tension would suggest either uncertainties not accounted for in the experimental estimates or the discovery of new physics beyond the standard model of cosmology. In this paper we examine in detail the tension between the CMB, BAO, and cosmic distance ladder data sets. We find that these measurements are consistent within reasonable statistical expectations and we combine them to determine a best-fit Hubble constant of 69.6 ± 0.7 km s{sup –1} Mpc{sup –1}. This value is based upon WMAP9+SPT+ACT+6dFGS+BOSS/DR11+H {sub 0}/Riess; we explore alternate data combinations in the text. The combined data constrain the Hubble constant to 1%, with no compelling evidence for new physics.
Varying Fine-Structure Constant and the Cosmological Constant Problem
Fujii, Y
2003-01-01
We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time-variability of the fine- structure constant $\\alpha$. Comparing this with the recent result from the measurement of distant QSO's appears to indicate a non-uniform time-dependence, which we argue to be related to another recent finding of the accelerating universe. This view is implemented in terms of the scalar-tensor theory, applied specifically to the small but nonzero cosmological constant. Our detailed calculation shows that these two phenomena can be understood in terms of a common origin, a particular behavior of the scalar field, dilaton. We also sketch how this theoretical approach makes it appropriate to revisit non- Newtonian gravity featuring small violation of Weak Equivalence Principle at medium distances.
Varying Fine-Structure Constant and the Cosmological Constant Problem
Fujii, Yasunori
We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time variability of the fine-structure constant α. Comparing this with the recent result from the measurement of distant QSO's appears to indicate a non-uniform time-dependence, which we argue to be related to another recent finding of the accelerating universe. This view is implemented in terms of the scalar-tensor theory, applied specifically to the small but nonzero cosmological constant. Our detailed calculation shows that these two phenomena can be understood in terms of a common origin, a particular behavior of the scalar field, dilaton. We also sketch how this theoretical approach makes it appropriate to revisit non-Newtonian gravity featuring small violation of Weak Equivalence Principle at medium distances.
Murphy, M T; Flambaum, V V; Dzuba, V A; Churchill, C W; Prochaska, J X; Barrow, John D; Wolfe, A M
2001-01-01
An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar absorption line spectra with laboratory spectra provides a sensitive probe for variability of the fine structure constant, alpha, over cosmological time-scales. We have previously developed and applied a new method providing an order of magnitude gain in precision over previous optical astrophysical constraints. Here we extend that work by including new quasar spectra of damped Lyman-alpha absorption systems. We also re-analyse our previous lower redshift data and confirm our initial results. The constraints on alpha come from simultaneous fitting of absorption lines of subsets of the following species: Mg I, Mg II, Al II, Al III, Si II, Cr II, Fe II, Ni II and Zn II. We present a detailed description of our methods and results based on an analysis of 49 quasar absorption systems (towards 28 QSOs) covering the redshift range 0.5 < z < 3.5. There is...
Fundamentals of Managing Reference Collections
Singer, Carol A.
2012-01-01
Whether a library's reference collection is large or small, it needs constant attention. Singer's book offers information and insight on best practices for reference collection management, no matter the size, and shows why managing without a plan is a recipe for clutter and confusion. In this very practical guide, reference librarians will learn:…
Fundamentals of Managing Reference Collections
Singer, Carol A.
2012-01-01
Whether a library's reference collection is large or small, it needs constant attention. Singer's book offers information and insight on best practices for reference collection management, no matter the size, and shows why managing without a plan is a recipe for clutter and confusion. In this very practical guide, reference librarians will learn:…
Constant-bandwidth constant-temperature hot-wire anemometer.
Ligeza, P
2007-07-01
A constant-temperature anemometer (CTA) enables the measurement of fast-changing velocity fluctuations. In the classical solution of CTA, the transmission band is a function of flow velocity. This is a minor drawback when the mean flow velocity does not significantly change, though it might lead to dynamic errors when flow velocity varies over a considerable range. A modification is outlined, whereby an adaptive controller is incorporated in the CTA system such that the anemometer's transmission band remains constant in the function of flow velocity. For that purpose, a second feedback loop is provided, and the output signal from the anemometer will regulate the controller's parameters such that the transmission bandwidth remains constant. The mathematical model of a CTA that has been developed and model testing data allow a through evaluation of the proposed solution. A modified anemometer can be used in measurements of high-frequency variable flows in a wide range of velocities. The proposed modification allows the minimization of dynamic measurement errors.
COMPARATIVE ANALYSIS BETWEEN THE FUNDAMENTAL AND TECHNICAL ANALYSIS OF STOCKS
Directory of Open Access Journals (Sweden)
Nada Petrusheva
2016-04-01
Full Text Available In the world of investing and trading, in order to have a definite advantage and constantly create profit, you need to have a strategic approach. Generally speaking, the two main schools of thought and strategies in financial markets are fundamental and technical analysis. Fundamental and technical analysis differ in several aspects, such as the way of functioning and execution, the time horizon used, the tools used and their objective. These differences lead to certain advantages and disadvantages of each of the analyses. Fundamental and technical analysis are also a subject of critical reviews by the academic and scientific community and many of these reviews concern the methods of their application, i.e. the possibility of combining the two analyses and using them complementarily to fully utilize their strengths and advantages.
Fundamental neutron physics at LANSCE
Energy Technology Data Exchange (ETDEWEB)
Greene, G.
1995-10-01
Modern neutron sources and science share a common origin in mid-20th-century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for studying condensed matter with modern neutron sources being primarily used (and justified) as tools for neutron scattering and materials science research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities performed at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high-flux neutron facilities. Future sources, particularly high-power spallation sources, offer exciting possibilities for continuing this research.
THE FUNDAMENTS OF EXPLANATORY CAUSES
Directory of Open Access Journals (Sweden)
Lavinia Mihaela VLĂDILĂ
2015-07-01
Full Text Available The new Criminal Code in the specter of the legal life the division of causes removing the criminal feature of the offence in explanatory causes and non-attributable causes. This dichotomy is not without legal and factual fundaments and has been subjected to doctrinaire debates even since the period when the Criminal Code of 1969 was still in force. From our perspective, one of the possible legal fundaments of the explanatory causes results from that the offence committed is based on the protection of a right at least equal with the one prejudiced by the action of aggression, salvation, by the legal obligation imposed or by the victim’s consent.
Fundamentals of condensed matter physics
Cohen, Marvin L
2016-01-01
Based on an established course and covering the fundamentals, central areas, and contemporary topics of this diverse field, Fundamentals of Condensed Matter Physics is a much-needed textbook for graduate students. The book begins with an introduction to the modern conceptual models of a solid from the points of view of interacting atoms and elementary excitations. It then provides students with a thorough grounding in electronic structure as a starting point to understand many properties of condensed matter systems - electronic, structural, vibrational, thermal, optical, transport, magnetic and superconductivity - and methods to calculate them. Taking readers through the concepts and techniques, the text gives both theoretically and experimentally inclined students the knowledge needed for research and teaching careers in this field. It features 200 illustrations, 40 worked examples and 150 homework problems for students to test their understanding. Solutions to the problems for instructors are available at w...
Astrophysical Probes of Fundamental Physics
Martins, C J A P
2006-01-01
I review the theoretical motivation for varying fundamental couplings and discuss how these measurements can be used to constrain a number of fundamental physics scenarios that would otherwise be inacessible to experiment. As a case study I will focus on the relation between varying couplings and dark energy, and explain how varying coupling measurements can be used to probe the nature of dark energy, with important advantages over the standard methods. Assuming that the current observational evidence for varying $\\alpha$ and $\\mu$ is correct, a several-sigma detection of dynamical dark energy is feasible within a few years, using currently operational ground-based facilities. With forthcoming instruments like CODEX, a high-accuracy reconstruction of the equation of state may be possible all the way up to redshift $z\\sim4$.
Fundamental investigations of catalyst nanoparticles
DEFF Research Database (Denmark)
Elkjær, Christian Fink
fundamental understanding of catalytic processes and our ability to make use of that understanding. This thesis presents fundamental studies of catalyst nanoparticles with particular focus on dynamic processes. Such studies often require atomic-scale characterization, because the catalytic conversion takes...... place on the molecular and atomic level. Transmission electron microscopy (TEM) has the ability to image nanostructures with atomic resolution and reveal the atomic configuration of the important nanoparticle surfaces. In the present work, TEM has been used to study nanoparticles in situ at elevated...... different topics, each related to different aspects of nanoparticle dynamics and catalysis. The first topic is the reduction of a homogeneous solid state precursor to form the catalytically active phase which is metal nanoparticles on an inert support. Here, we have reduced Cu phyllosilicate to Cu on silica...
Fundamentals of estuarine physical oceanography
Bruner de Miranda, Luiz; Kjerfve, Björn; Castro Filho, Belmiro Mendes de
2017-01-01
This book provides an introduction to the complex system functions, variability and human interference in ecosystem between the continent and the ocean. It focuses on circulation, transport and mixing of estuarine and coastal water masses, which is ultimately related to an understanding of the hydrographic and hydrodynamic characteristics (salinity, temperature, density and circulation), mixing processes (advection and diffusion), transport timescales such as the residence time and the exposure time. In the area of physical oceanography, experiments using these water bodies as a natural laboratory and interpreting their circulation and mixing processes using theoretical and semi-theoretical knowledge are of fundamental importance. Small-scale physical models may also be used together with analytical and numerical models. The book highlights the fact that research and theory are interactive, and the results provide the fundamentals for the development of the estuarine research.
Fundamentals of electronic systems design
Lienig, Jens
2017-01-01
This textbook covers the design of electronic systems from the ground up, from drawing and CAD essentials to recycling requirements. Chapter by chapter, it deals with the challenges any modern system designer faces: the design process and its fundamentals, such as technical drawings and CAD, electronic system levels, assembly and packaging issues and appliance protection classes, reliability analysis, thermal management and cooling, electromagnetic compatibility (EMC), all the way to recycling requirements and environmental-friendly design principles. Enables readers to face various challenges of designing electronic systems, including coverage from various engineering disciplines; Written to be accessible to readers of varying backgrounds; Uses illustrations extensively to reinforce fundamental concepts; Organized to follow essential design process, although chapters are self-contained and can be read in any order.
Unified Theory of Fundamental Interactions
Institute of Scientific and Technical Information of China (English)
WU Ning
2003-01-01
Based on local gauge invariance, four different kinds of fundamental interactions in nature are unified in a theory which has SU(3)C( )SU SU(2)L( )U(1)( )s Gravitational Gauge Group gauge symmetry. In this approach,gravitational field, like electromagnetic field, intermediate gauge field, and gluon field, is represented by gauge potential.Four kinds of fundamental interactions are formulated in the similar manner, and therefore can be unified in a direct or semi-direct product group. The model discussed in this paper is a renormalizable quantum model and can be regarded as an extension of the standard model to gravitational interactions, so it can be used to study quantum effects of gravitational interactions.
Composing Europe's Fundamental Rights Area
DEFF Research Database (Denmark)
Storgaard, Louise Halleskov
2015-01-01
The article offers a perspective on how the objective of a strong and coherent European protection standard pursued by the fundamental rights amendments of the Lisbon Treaty can be achieved, as it proposes a discursive pluralistic framework to understand and guide the relationship between the EU...... Court of Justice and the European Court of Human Rights. It is argued that this framework – which is suggested as an alternative to the EU law approach to the Strasbourg system applied by the CJEU in Opinion 2/13 and its Charter-based case law – has a firm doctrinal, case law and normative basis....... The article ends by addressing three of the most pertinent challenges to European fundamental rights protection through the prism of the proposed framework....
Modern measurements fundamentals and applications
Petri, D; Carbone, P; Catelani, M
2015-01-01
This book explores the modern role of measurement science for both the technically most advanced applications and in everyday and will help readers gain the necessary skills to specialize their knowledge for a specific field in measurement. Modern Measurements is divided into two parts. Part I (Fundamentals) presents a model of the modern measurement activity and the already recalled fundamental bricks. It starts with a general description that introduces these bricks and the uncertainty concept. The next chapters provide an overview of these bricks and ﬁnishes (Chapter 7) with a more general and complex model that encompasses both traditional (hard) measurements and (soft) measurements, aimed at quantifying non-physical concepts, such as quality, satisfaction, comfort, etc. Part II (Applications) is aimed at showing how the concepts presented in Part I can be usefully applied to design and implement measurements in some very impor ant and broad ﬁelds. The editors cover System Identiﬁcation (Chapter 8...
Fundamentals of plastic optical fibers
Koike, Yasuhiro
2014-01-01
Polymer photonics is an interdisciplinary field which demands excellence both in optics (photonics) and materials science (polymer). However, theses disciplines have developed independently, and therefore the demand for a comprehensive work featuring the fundamentals of photonic polymers is greater than ever.This volume focuses on Polymer Optical Fiber and their applications. The first part of the book introduces typical optical fibers according to their classifications of material, propagating mode, and structure. Optical properties, the high bandwidth POF and transmission loss are discussed,
Fundamental Scaling Laws in Nanophotonics
Ke Liu; Shuai Sun; Arka Majumdar; Volker J. Sorger
2016-01-01
The success of information technology has clearly demonstrated that miniaturization often leads to unprecedented performance, and unanticipated applications. This hypothesis of “smaller-is-better” has motivated optical engineers to build various nanophotonic devices, although an understanding leading to fundamental scaling behavior for this new class of devices is missing. Here we analyze scaling laws for optoelectronic devices operating at micro and nanometer length-scale. We show that optoe...
Fundamental Composite (Goldstone) Higgs Dynamics
DEFF Research Database (Denmark)
Cacciapaglia, G.; Sannino, Francesco
2014-01-01
We provide a unified description, both at the effective and fundamental Lagrangian level, of models of composite Higgs dynamics where the Higgs itself can emerge, depending on the way the electroweak symmetry is embedded, either as a pseudo-Goldstone boson or as a massive excitation of the conden......We provide a unified description, both at the effective and fundamental Lagrangian level, of models of composite Higgs dynamics where the Higgs itself can emerge, depending on the way the electroweak symmetry is embedded, either as a pseudo-Goldstone boson or as a massive excitation...... of the condensate. We show that, in general, these states mix with repercussions on the electroweak physics and phenomenology. Our results will help clarify the main differences, similarities, benefits and shortcomings of the different ways one can naturally realize a composite nature of the electroweak sector...... transforming according to the fundamental representation of the gauge group. This minimal choice enables us to use recent first principle lattice results to make the first predictions for the massive spectrum for models of composite (Goldstone) Higgs dynamics. These results are of the upmost relevance to guide...
How does Planck’s constant influence the macroscopic world?
Yang, Pao-Keng
2016-09-01
In physics, Planck’s constant is a fundamental physical constant accounting for the energy-quantization phenomenon in the microscopic world. The value of Planck’s constant also determines in which length scale the quantum phenomenon will become conspicuous. Some students think that if Planck’s constant were to have a larger value than it has now, the quantum effect would only become observable in a world with a larger size, whereas the macroscopic world might remain almost unchanged. After reasoning from some basic physical principles and theories, we found that doubling Planck’s constant might result in a radical change on the geometric sizes and apparent colors of macroscopic objects, the solar spectrum and luminosity, the climate and gravity on Earth, as well as energy conversion between light and materials such as the efficiency of solar cells and light-emitting diodes. From the discussions in this paper, students can appreciate how Planck’s constant affects various aspects of the world in which we are living now.
Low uncertainty Boltzmann constant determinations and the kelvin redefinition.
Fischer, J
2016-03-28
At its 25th meeting, the General Conference on Weights and Measures (CGPM) approved Resolution 1 'On the future revision of the International System of Units, the SI', which sets the path towards redefinition of four base units at the next CGPM in 2018. This constitutes a decisive advance towards the formal adoption of the new SI and its implementation. Kilogram, ampere, kelvin and mole will be defined in terms of fixed numerical values of the Planck constant, elementary charge, Boltzmann constant and Avogadro constant, respectively. The effect of the new definition of the kelvin referenced to the value of the Boltzmann constant k is that the kelvin is equal to the change of thermodynamic temperature T that results in a change of thermal energy kT by 1.380 65×10(-23) J. A value of the Boltzmann constant suitable for defining the kelvin is determined by fundamentally different primary thermometers such as acoustic gas thermometers, dielectric constant gas thermometers, noise thermometers and the Doppler broadening technique. Progress to date of the measurements and further perspectives are reported. Necessary conditions to be met before proceeding with changing the definition are given. The consequences of the new definition of the kelvin on temperature measurement are briefly outlined. © 2016 The Author(s).
Lepton Collider Operation with Constant Currents
Wienands, Ulrich
2005-01-01
Traditionally, electron-positron colliders have been operating in a top-off-and-coast fashion with a cycle time depending on the beam life time, typically on the order of an hour. Each top-off involves ramping detector systems in addition to the actual filling time. The loss in accumulated luminosity is typically 20-50%. During the last year, both B-Factories have commissioned a continuous-injection mode of operation in which beam is injected without ramping the detector, thus raising luminosity integration by constant operation at peak luminosity. Constant beam currents reduce thermal drift and trips caused by change in beam loading. To achieve this level of operation, special efforts were made to reduce the injection losses and also to implement special gating procedures in the detectors, minimizing dead time. Bunch-injection control decides which bunch to inject into next while maintaining small charge variation between bunches. Beam collimation can reduce injection noise but also cause an increase in back...
Three pion nucleon coupling constants
Arriola, E Ruiz; Perez, R Navarro
2016-01-01
There exist four pion nucleon coupling constants, $f_{\\pi^0, pp}$, $-f_{\\pi^0, nn}$, $f_{\\pi^+, pn} /\\sqrt{2}$ and $ f_{\\pi^-, np} /\\sqrt{2}$ which coincide when up and down quark masses are identical and the electron charge is zero. While there is no reason why the pion-nucleon-nucleon coupling constants should be identical in the real world, one expects that the small differences might be pinned down from a sufficiently large number of independent and mutually consistent data. Our discussion provides a rationale for our recent determination $$f_p^2 = 0.0759(4) \\, , \\quad f_{0}^2 = 0.079(1) \\,, \\quad f_{c}^2 = 0.0763(6) \\, , $$ based on a partial wave analysis of the $3\\sigma$ self-consistent nucleon-nucleon Granada-2013 database comprising 6713 published data in the period 1950-2013.
Perspective: tipping the scales: search for drifting constants from molecular spectra.
Jansen, Paul; Bethlem, Hendrick L; Ubachs, Wim
2014-01-07
Transitions in atoms and molecules provide an ideal test ground for constraining or detecting a possible variation of the fundamental constants of nature. In this perspective, we review molecular species that are of specific interest in the search for a drifting proton-to-electron mass ratio μ. In particular, we outline the procedures that are used to calculate the sensitivity coefficients for transitions in these molecules and discuss current searches. These methods have led to a rate of change in μ bounded to 6 × 10(-14)/yr from a laboratory experiment performed in the present epoch. On a cosmological time scale, the variation is limited to ∣Δμ∕μ∣ < 10(-5) for look-back times of 10-12× 10(9) years and to ∣Δμ∕μ∣ < 10(-7) for look-back times of 7× 10(9) years. The last result, obtained from high-redshift observation of methanol, translates into μ̇/μ=(1.4±1.4)×10(-17)/yr if a linear rate of change is assumed.
Perspective: Tipping the scales - search for drifting constants from molecular spectra
Jansen, Paul; Ubachs, Wim
2013-01-01
Transitions in atoms and molecules provide an ideal test ground for constraining or detecting a possible variation of the fundamental constants of nature. In this Perspective, we review molecular species that are of specific interest in the search for a drifting proton-to-electron mass ratio $\\mu$. In particular, we outline the procedures that are used to calculate the sensitivity coefficients for transitions in these molecules and discuss current searches. These methods have led to a rate of change in $\\mu$ bounded to $6 \\times 10^{-14}$/yr from a laboratory experiment performed in the present epoch. On a cosmological time scale the variation is limited to $|\\Delta\\mu/\\mu| < 10^{-5}$ for look-back times of 10-12 billion years and to $|\\Delta\\mu/\\mu| < 10^{-7}$ for look-back times of 7 billion years. The last result, obtained from high-redshift observation of methanol, translates into $\\dot{\\mu}/\\mu = (1.4 \\pm 1.4) \\times 10^{-17}$/yr if a linear rate of change is assumed.
Iorio, Lorenzo
2016-01-01
A sinusoidally time-varying pattern for the values of the Newton's constant of gravitation $G$ measured in Earth-based laboratories over the latest decades has been recently reported in the literature. Its amplitude and period amount to $A_G=1.619\\times 10^{-14} \\textrm{kg}^{-1} \\textrm{m}^3 \\textrm{s}^{-2}, P_G=5.899 \\textrm{yr}$, respectively. Given the fundamental role played by $G$ in the currently accepted theory of gravitation and the attempts to merge it with quantum mechanics, it is important to put to the test the hypothesis that the aforementioned harmonic variation may pertain $G$ itself in a direct and independent way. The bounds on $\\dot G/G$ existing in the literature may not be extended straightforwardly to the present case since they were inferred by considering just secular variations. Thus, we numerically integrated the ad-hoc modified equations of motion of the major bodies of the Solar System by finding that the orbits of the planets would be altered by an unacceptably larger amount in vie...
Fine-structure constant: Is it really a constant?
Bekenstein, Jacob D.
1982-03-01
It is often claimed that the fine-structure "constant" α is shown to be strictly constant in time by a variety of astronomical and geophysical results. These constrain its fractional rate of change α˙α to at least some orders of magnitude below the Hubble rate H0. We argue that the conclusion is not as straightforward as claimed since there are good physical reasons to expect α˙α<
Fundamental Limits to Cellular Sensing
ten Wolde, Pieter Rein; Becker, Nils B.; Ouldridge, Thomas E.; Mugler, Andrew
2016-03-01
In recent years experiments have demonstrated that living cells can measure low chemical concentrations with high precision, and much progress has been made in understanding what sets the fundamental limit to the precision of chemical sensing. Chemical concentration measurements start with the binding of ligand molecules to receptor proteins, which is an inherently noisy process, especially at low concentrations. The signaling networks that transmit the information on the ligand concentration from the receptors into the cell have to filter this receptor input noise as much as possible. These networks, however, are also intrinsically stochastic in nature, which means that they will also add noise to the transmitted signal. In this review, we will first discuss how the diffusive transport and binding of ligand to the receptor sets the receptor correlation time, which is the timescale over which fluctuations in the state of the receptor, arising from the stochastic receptor-ligand binding, decay. We then describe how downstream signaling pathways integrate these receptor-state fluctuations, and how the number of receptors, the receptor correlation time, and the effective integration time set by the downstream network, together impose a fundamental limit on the precision of sensing. We then discuss how cells can remove the receptor input noise while simultaneously suppressing the intrinsic noise in the signaling network. We describe why this mechanism of time integration requires three classes (groups) of resources—receptors and their integration time, readout molecules, energy—and how each resource class sets a fundamental sensing limit. We also briefly discuss the scheme of maximum-likelihood estimation, the role of receptor cooperativity, and how cellular copy protocols differ from canonical copy protocols typically considered in the computational literature, explaining why cellular sensing systems can never reach the Landauer limit on the optimal trade
Fundamental cycles and graph embeddings
Institute of Scientific and Technical Information of China (English)
2009-01-01
In this paper, we investigate fundamental cycles in a graph G and their relations with graph embeddings. We show that a graph G may be embedded in an orientable surface with genus at least g if and only if for any spanning tree T , there exists a sequence of fundamental cycles C1, C2, . . . , C2g with C2i-1 ∩ C2i≠ф for 1≤ i ≤g. In particular, among β(G) fundamental cycles of any spanning tree T of a graph G, there are exactly 2γM (G) cycles C1, C2, . . . , C2γM (G) such that C2i-1 ∩ C2i≠ф for 1 ≤i≤γM (G), where β(G) and γM (G) are the Betti number and the maximum genus of G, respectively. This implies that it is possible to construct an orientable embedding with large genus of a graph G from an arbitrary spanning tree T (which may have very large number of odd components in G\\E(T )). This is different from the earlier work of Xuong and Liu, where spanning trees with small odd components are needed. In fact, this makes a common generalization of Xuong, Liu and Fu et al. Furthermore, we show that (1) this result is useful for locating the maximum genus of a graph having a specific edge-cut. Some known results for embedded graphs are also concluded; (2) the maximum genus problem may be reduced to the maximum matching problem. Based on this result and the algorithm of Micali-Vazirani, we present a new efficient algorithm to determine the maximum genus of a graph in O((β(G)) 25 ) steps. Our method is straight and quite different from the algorithm of Furst, Gross and McGeoch which depends on a result of Giles where matroid parity method is needed.
Institute of Scientific and Technical Information of China (English)
曹美春; 林朝晖; 张贺
2014-01-01
In this paper, the impact of total solar irradiance (i.e., solar constant) variation upon global radiative forcing and climate change in winter (December-February) is investigated by using a global atmospheric general circulation model (IAP AGCM4.0). Two sets of numerical experiments are designed, with one using the default solar constant (1367W·m-2) and the other adopting the latest value (1361W·m-2). Comparisons of the model results from both experiments demonstrate that with the reduction of solar constant:(1) Incoming solar radiation decreases 1.54W·m-2 globally and 2.15W·m-2 over areas of the mid-and high-latitudes in the Southern Hemisphere. Corresponding to less total cloud cover, net solar radiation at the top of the atmosphere and the surface increases in regions such as North America, West Siberia, Middle East, and Eastern Australia;(2) Surface temperature decreases 0.05℃ globally and more than 2℃ over Eurasia, while it increases about 0.5℃ over Eastern Australia. In other regions such as Southern North-America, Southern South-America, Eastern and Southern Africa, and Western Australia, surface temperature becomes colder. Over regions including Northern North-America, Northern South-America, and Western Africa, surface temperature becomes warmer. (3) Precipitation exhibits negligible variations when averaged globally, which only drops by 0.003 mm·d-1. Owing to the combined effects of decreased surface evapotranspiration, reduced surface humidity, and weakened Australian summer monsoon, precipitation over Eastern Australia is on average reduced by about 0.6 mm·d-1.%利用中国科学院大气物理研究所第四代大气环流模式IAP AGCM4.0，通过在模式中将太阳常数从1367W·m-2减少至1361W·m-2，探讨了太阳总辐射减弱对冬季（12-2月）全球辐射强迫及气候模拟的影响。结果表明：（1）大气顶入射太阳辐射在全球范围内平均减少1.54W·m-2，南半球中高纬地区显著减少2.15W·m-2
Predicting Achievable Fundamental Frequency Ranges in Vocalization Across Species.
Directory of Open Access Journals (Sweden)
Ingo Titze
2016-06-01
Full Text Available Vocal folds are used as sound sources in various species, but it is unknown how vocal fold morphologies are optimized for different acoustic objectives. Here we identify two main variables affecting range of vocal fold vibration frequency, namely vocal fold elongation and tissue fiber stress. A simple vibrating string model is used to predict fundamental frequency ranges across species of different vocal fold sizes. While average fundamental frequency is predominantly determined by vocal fold length (larynx size, range of fundamental frequency is facilitated by (1 laryngeal muscles that control elongation and by (2 nonlinearity in tissue fiber tension. One adaptation that would increase fundamental frequency range is greater freedom in joint rotation or gliding of two cartilages (thyroid and cricoid, so that vocal fold length change is maximized. Alternatively, tissue layers can develop to bear a disproportionate fiber tension (i.e., a ligament with high density collagen fibers, increasing the fundamental frequency range and thereby vocal versatility. The range of fundamental frequency across species is thus not simply one-dimensional, but can be conceptualized as the dependent variable in a multi-dimensional morphospace. In humans, this could allow for variations that could be clinically important for voice therapy and vocal fold repair. Alternative solutions could also have importance in vocal training for singing and other highly-skilled vocalizations.
Evaluation of the Lazarus Leblond constants in the asymptotic model of the interfacial wavy crack
Piccolroaz, A.; Mishuris, G.; Movchan, A. B.
2007-08-01
The paper addresses the problem of a semi-infinite plane crack along the interface between two isotropic half-spaces. Two methods of solution have been considered in the past: Lazarus and Leblond [1998a. Three-dimensional crack-face weight functions for the semi-infinite interface crack-I: variation of the stress intensity factors due to some small perturbation of the crack front. J. Mech. Phys. Solids 46, 489-511, 1998b. Three-dimensional crack-face weight functions for the semi-infinite interface crack-II: integrodifferential equations on the weight functions and resolution J. Mech. Phys. Solids 46, 513-536] applied the "special" method by Bueckner [1987. Weight functions and fundamental fields for the penny-shaped and the half-plane crack in three space. Int. J. Solids Struct. 23, 57-93] and found the expression of the variation of the stress intensity factors for a wavy crack without solving the complete elasticity problem; their solution is expressed in terms of the physical variables, and it involves five constants whose analytical representation was unknown; on the other hand, the "general" solution to the problem has been recently addressed by Bercial-Velez et al. [2005. High-order asymptotics and perturbation problems for 3D interfacial cracks. J. Mech. Phys. Solids 53, 1128-1162], using a Wiener-Hopf analysis and singular asymptotics near the crack front. The main goal of the present paper is to complete the solution to the problem by providing the connection between the two methods. This is done by constructing an integral representation for Lazarus-Leblond's weight functions and by deriving the closed form representations of Lazarus-Leblond's constants.
Computing fundamentals introduction to computers
Wempen, Faithe
2014-01-01
The absolute beginner's guide to learning basic computer skills Computing Fundamentals, Introduction to Computers gets you up to speed on basic computing skills, showing you everything you need to know to conquer entry-level computing courses. Written by a Microsoft Office Master Instructor, this useful guide walks you step-by-step through the most important concepts and skills you need to be proficient on the computer, using nontechnical, easy-to-understand language. You'll start at the very beginning, getting acquainted with the actual, physical machine, then progress through the most common
Computing fundamentals digital literacy edition
Wempen, Faithe
2014-01-01
Computing Fundamentals has been tailor made to help you get up to speed on your Computing Basics and help you get proficient in entry level computing skills. Covering all the key topics, it starts at the beginning and takes you through basic set-up so that you'll be competent on a computer in no time.You'll cover: Computer Basics & HardwareSoftwareIntroduction to Windows 7Microsoft OfficeWord processing with Microsoft Word 2010Creating Spreadsheets with Microsoft ExcelCreating Presentation Graphics with PowerPointConnectivity and CommunicationWeb BasicsNetwork and Internet Privacy and Securit
Photovoltaics fundamentals, technology and practice
Mertens, Konrad
2013-01-01
Concise introduction to the basic principles of solar energy, photovoltaic systems, photovoltaic cells, photovoltaic measurement techniques, and grid connected systems, overviewing the potential of photovoltaic electricity for students and engineers new to the topic After a brief introduction to the topic of photovoltaics' history and the most important facts, Chapter 1 presents the subject of radiation, covering properties of solar radiation, radiation offer, and world energy consumption. Chapter 2 looks at the fundamentals of semiconductor physics. It discusses the build-up of semiconducto
Solid Lubrication Fundamentals and Applications
Miyoshi, Kazuhisa
2001-01-01
Solid Lubrication Fundamentals and Applications description of the adhesion, friction, abrasion, and wear behavior of solid film lubricants and related tribological materials, including diamond and diamond-like solid films. The book details the properties of solid surfaces, clean surfaces, and contaminated surfaces as well as discussing the structures and mechanical properties of natural and synthetic diamonds; chemical-vapor-deposited diamond film; surface design and engineering toward wear-resistant, self-lubricating diamond films and coatings. The author provides selection and design criteria as well as applications for synthetic and natural coatings in the commercial, industrial and aerospace industries..
Fundamentals of liquid crystal devices
Yang, Deng-Ke
2014-01-01
Revised throughout to cover the latest developments in the fast moving area of display technology, this 2nd edition of Fundamentals of Liquid Crystal Devices, will continue to be a valuable resource for those wishing to understand the operation of liquid crystal displays. Significant updates include new material on display components, 3D LCDs and blue-phase displays which is one of the most promising new technologies within the field of displays and it is expected that this new LC-technology will reduce the response time and the number of optical components of LC-modules. Prof. Yang is a pion
Fundamentals of ultrasonic phased arrays
Schmerr, Lester W
2014-01-01
This book describes in detail the physical and mathematical foundations of ultrasonic phased array measurements.?The book uses linear systems theory to develop a comprehensive model of the signals and images that can be formed with phased arrays. Engineers working in the field of ultrasonic nondestructive evaluation (NDE) will find in this approach a wealth of information on how to design, optimize and interpret ultrasonic inspections with phased arrays. The fundamentals and models described in the book will also be of significant interest to other fields, including the medical ultrasound and