Bliokh, Konstantin Y; Nori, Franco
2012-03-23
We consider the relativistic deformation of quantum waves and mechanical bodies carrying intrinsic angular momentum (AM). When observed in a moving reference frame, the centroid of the object undergoes an AM-dependent transverse shift. This is the relativistic analogue of the spin-Hall effect, which occurs in free space without any external fields. Remarkably, the shifts of the geometric and energy centroids differ by a factor of 2, and both centroids are crucial for the Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices and mechanical flywheels and also discuss various fundamental aspects of this phenomenon. The perfect agreement of quantum and relativistic approaches allows applications at strikingly different scales, from elementary spinning particles, through classical light, to rotating black holes. PMID:22540559
Perspective: relativistic effects.
Autschbach, Jochen
2012-04-21
This perspective article discusses some broadly-known and some less broadly-known consequences of Einstein's special relativity in quantum chemistry, and provides a brief outline of the theoretical methods currently in use, along with a discussion of recent developments and selected applications. The treatment of the electron correlation problem in relativistic quantum chemistry methods, and expanding the reach of the available relativistic methods to calculate all kinds of energy derivative properties, in particular spectroscopic and magnetic properties, requires on-going efforts. PMID:22519307
MP2 calculation of (77) Se NMR chemical shifts taking into account relativistic corrections.
Rusakov, Yury Yu; Rusakova, Irina L; Krivdin, Leonid B
2015-07-01
The main factors affecting the accuracy and computational cost of the Second-order Möller-Plesset perturbation theory (MP2) calculation of (77) Se NMR chemical shifts (methods and basis sets, relativistic corrections, and solvent effects) are addressed with a special emphasis on relativistic effects. For the latter, paramagnetic contribution (390-466 ppm) dominates over diamagnetic term (192-198 ppm) resulting in a total shielding relativistic correction of about 230-260 ppm (some 15% of the total values of selenium absolute shielding constants). Diamagnetic term is practically constant, while paramagnetic contribution spans over 70-80 ppm. In the (77) Se NMR chemical shifts scale, relativistic corrections are about 20-30 ppm (some 5% of the total values of selenium chemical shifts). Solvent effects evaluated within the polarizable continuum solvation model are of the same order of magnitude as relativistic corrections (about 5%). For the practical calculations of (77) Se NMR chemical shifts of the medium-sized organoselenium compounds, the most efficient computational protocols employing relativistic Dyall's basis sets and taking into account relativistic and solvent corrections are suggested. The best result is characterized by a mean absolute error of 17 ppm for the span of (77) Se NMR chemical shifts reaching 2500 ppm resulting in a mean absolute percentage error of 0.7%. PMID:25998325
Relativistic spin effects in the baryon spectrum
Garcilazo, Humberto
2005-04-01
We study the nonstrange baryon spectrum within a three-body theory that treats relativistically both the space and the spin variables. The relativistic effects of the spin are about one order of magnitude smaller than those due to the use of relativistic momentum variables. The relativistic treatment of the spin breaks the degenerancy that is present in the nonrelativistic model and in the model with only relativistic momentum variables.
Relativistic effects on x-ray structure factors
NASA Astrophysics Data System (ADS)
Batke, Kilian; Eickerling, Georg
2016-04-01
Today, combined experimental and theoretical charge density studies based on quantum chemical calculations and x-ray diffraction experiments allow for the investigation of the topology of the electron density at subatomic resolution. When studying compounds containing transition metal elements, relativistic effects need to be adequately taken into account not only in quantum chemical calculations of the total electron density ρ ({r}), but also for the atomic scattering factors employed to extract ρ ({r}) from experimental x-ray diffraction data. In the present study, we investigate the magnitude of relativistic effects on x-ray structure factors and for this purpose {F}({{r}}*) have been calculated for the model systems M(C2H2) (M = Ni, Pd, Pt) from four-component molecular wave functions. Relativistic effects are then discussed by a comparison to structure factors obtained from a non-relativistic reference and different quasi-relativistic approximations. We show, that the overall effects of relativity on the structure factors on average amount to 0.81%, 1.51% and 2.78% for the three model systems under investigation, but that for individual reflections or reflection series the effects can be orders of magnitude larger. Employing the quasi-relativistic Douglas-Kroll-Hess second order or the zeroth order regular approximation Hamiltonian takes these effects into account to a large extend, reducing the differences between the (quasi-)relativistic and the non-relativistic result by one order of magnitude. In order to further determine the experimental significance of the results, the magnitude of the relativistic effects is compared to the changes of the model structure factor data when charge transfer and chemical bonding is taken into account by a multipolar expansion of {F}({{r}}*).
Relativistic effects on plasma expansion
Benkhelifa, El-Amine; Djebli, Mourad
2014-07-15
The expansion of electron-ion plasma is studied through a fully relativistic multi-fluids plasma model which includes thermal pressure, ambipolar electrostatic potential, and internal energy conversion. Numerical investigation, based on quasi-neutral assumption, is performed for three different regimes: nonrelativistic, weakly relativistic, and relativistic. Ions' front in weakly relativistic regime exhibits spiky structure associated with a break-down of quasi-neutrality at the expanding front. In the relativistic regime, ion velocity is found to reach a saturation limit which occurs at earlier stages of the expansion. This limit is enhanced by higher electron velocity.
NASA Astrophysics Data System (ADS)
Bogdanov, O. V.; Fiks, E. I.; Pivovarov, Yu. L.
2012-09-01
Numerical methods are used to study the dependence of the structure and the width of the angular distribution of Vavilov-Cherenkov radiation with a fixed wavelength in the vicinity of the Cherenkov cone on the radiator parameters (thickness and refractive index), as well as on the parameters of the relativistic heavy ion beam (charge and initial energy). The deceleration of relativistic heavy ions in the radiator, which decreases the velocity of ions, modifies the condition of structural interference of the waves emitted from various segments of the trajectory; as a result, a complex distribution of Vavilov-Cherenkov radiation appears. The main quantity is the stopping power of a thin layer of the radiator (average loss of the ion energy), which is calculated by the Bethe-Bloch formula and using the SRIM code package. A simple formula is obtained to estimate the angular distribution width of Cherenkov radiation (with a fixed wavelength) from relativistic heavy ions taking into account the deceleration in the radiator. The measurement of this width can provide direct information on the charge of the ion that passes through the radiator, which extends the potentialities of Cherenkov detectors. The isotopic effect (dependence of the angular distribution of Vavilov-Cherenkov radiation on the ion mass) is also considered.
Bogdanov, O. V. Fiks, E. I.; Pivovarov, Yu. L.
2012-09-15
Numerical methods are used to study the dependence of the structure and the width of the angular distribution of Vavilov-Cherenkov radiation with a fixed wavelength in the vicinity of the Cherenkov cone on the radiator parameters (thickness and refractive index), as well as on the parameters of the relativistic heavy ion beam (charge and initial energy). The deceleration of relativistic heavy ions in the radiator, which decreases the velocity of ions, modifies the condition of structural interference of the waves emitted from various segments of the trajectory; as a result, a complex distribution of Vavilov-Cherenkov radiation appears. The main quantity is the stopping power of a thin layer of the radiator (average loss of the ion energy), which is calculated by the Bethe-Bloch formula and using the SRIM code package. A simple formula is obtained to estimate the angular distribution width of Cherenkov radiation (with a fixed wavelength) from relativistic heavy ions taking into account the deceleration in the radiator. The measurement of this width can provide direct information on the charge of the ion that passes through the radiator, which extends the potentialities of Cherenkov detectors. The isotopic effect (dependence of the angular distribution of Vavilov-Cherenkov radiation on the ion mass) is also considered.
Quantum Monte Carlo studies of relativistic effects in light nuclei
J. L. Forest; V. R. Pandharipande; A. Arriaga
1998-05-01
Relativistic Hamiltonians are defined as the sum of relativistic one-body kinetic energy, two- and three-body potentials and their boost corrections. In this work the authors use the variational Monte Carlo method to study two kinds of relativistic effects in the binding energy of {sup 3}H and {sup 4}He. The first is due to the nonlocalities in the relativistic kinetic energy and relativistic one-pion exchange potential (OPEP), and the second is from boost interaction. The OPEP contribution is reduced by about 15% by the relativistic nonlocality, which may also have significant effects on pion exchange currents. However, almost all of this reduction is canceled by changes in the kinetic energy and other interaction terms, and the total effect of the nonlocalities on the binding energy is very small. The boost interactions, on the other hand, give repulsive contributions of 0.4 (1.9) MeV in {sup 3}H ({sup 4}He) and account for 37% of the phenomenological part of the three-nucleon interaction needed in the nonrelativistic Hamiltonians.
Relativistic effects in Lyman-α forest
NASA Astrophysics Data System (ADS)
Iršič, Vid; Di Dio, Enea; Viel, Matteo
2016-02-01
We present the calculation of the Lyman-alpha (Lyman-α) transmitted flux fluctuations with full relativistic corrections to the first order. Even though several studies exist on relativistic effects in galaxy clustering, this is the first study to extend the formalism to a different tracer of underlying matter at unique redshift range (z=2-5). Furthermore, we show a comprehensive application of our calculations to the Quasar-Lyman-α cross-correlation function. Our results indicate that the signal of relativistic effects are sizeable at Baryonic Acoustic Oscillation (BAO) scale mainly due to the large differences in density bias factors of our tracers. We construct an observable, the anti-symmetric part of the cross-correlation function, that is dominated by the relativistic signal and offers a new way to measure the relativistic terms at relatively small scales. The analysis shows that relativistic effects are important when considering cross-correlations between tracers with very different biases, and should be included in the data analysis of the current and future surveys. Moreover, the idea presented in this paper is highly complementary to other techniques and observables trying to isolate the effect of the relativistic corrections and thus test the validity of the theory of gravity beyond the Newtonian regime.
Fedorov, Sergey V; Rusakov, Yury Yu; Krivdin, Leonid B
2015-06-01
Relativistic calculations of (29)Si NMR shielding constants (chemical shifts) in the series of halosilanes SiX(n)H(4-n) (X = F, Cl, Br and I) are performed within a full four-component relativistic Dirac's scheme using relativistic Dyall's basis sets. Three different theoretical levels are tested in the computation of (29)Si NMR chemical shifts in comparison with experiment: namely, four-component relativistic GIAO-DFT, four-component relativistic GIAO-RPA, and a hybrid scheme of a nonrelativistic GIAO-MP2 with taking into account relativistic corrections using the four-component relativistic GIAO-RPA. The DFT results give larger relativistic effects as compared to the RPA data which might be rationalized in terms of the manifestation of correlation effects taken into account at the DFT level and not accounted for at the uncorrelated RPA level. Taking into account solvent effects slightly improves agreement with experiment, however, being not a matter of principle. Generally, relativistic pure nonempirical wave function methods perform much better as compared to relativistic DFT methods when benchmarked to experiment. PMID:25946056
Relativistic Effects in Two Photon Decay of 0-+ Quarkonium
NASA Astrophysics Data System (ADS)
Zhou, H. Q.; Zou, B. S.
Relativistic effects in two photon decay of 0-+ quarkonium are investigated with a relativistic phenomenological approach. Comparing with the non-relativistic approximation, the relativistic phenomenological approach gives corrections coming from three sources: qbar q relative momentum distribution, qbar q relative energy distribution and description of quark spinors in the meson. These relativistic effects are studied in detail for cbar c and sbar s systems.
General relativistic effects in atom interferometry
Dimopoulos, Savas; Hogan, Jason M.; Kasevich, Mark A.; Graham, Peter W.
2008-08-15
Atom interferometry is now reaching sufficient precision to motivate laboratory tests of general relativity. We begin by explaining the nonrelativistic calculation of the phase shift in an atom interferometer and deriving its range of validity. From this, we develop a method for calculating the phase shift in general relativity. Both the atoms and the light are treated relativistically and all coordinate dependencies are removed, thus revealing novel terms, cancellations, and new origins for previously calculated terms. This formalism is then used to find the relativistic effects in an atom interferometer in a weak gravitational field for application to laboratory tests of general relativity. The potentially testable relativistic effects include the nonlinear three-graviton coupling, the gravity of kinetic energy, and the falling of light. We propose specific experiments, one currently under construction, to measure each of these effects. These experiments could provide a test of the principle of equivalence to 1 part in 10{sup 15} (300 times better than the present limit), and general relativity at the 10% level, with many potential future improvements. We also consider applications to other metrics including the Lense-Thirring effect, the expansion of the Universe, and preferred frame and location effects.
General Relativistic Effects in Atom Interferometry
Dimopoulos, Savas; Graham, Peter W.; Hogan, Jason M.; Kasevich, Mark A.; /Stanford U., Phys. Dept.
2008-03-17
Atom interferometry is now reaching sufficient precision to motivate laboratory tests of general relativity. We begin by explaining the non-relativistic calculation of the phase shift in an atom interferometer and deriving its range of validity. From this we develop a method for calculating the phase shift in general relativity. This formalism is then used to find the relativistic effects in an atom interferometer in a weak gravitational field for application to laboratory tests of general relativity. The potentially testable relativistic effects include the non-linear three-graviton coupling, the gravity of kinetic energy, and the falling of light. We propose experiments, one currently under construction, that could provide a test of the principle of equivalence to 1 part in 10{sup 15} (300 times better than the present limit), and general relativity at the 10% level, with many potential future improvements. We also consider applications to other metrics including the Lense-Thirring effect, the expansion of the universe, and preferred frame and location effects.
Finite nucleus effects on relativistic energy corrections
NASA Technical Reports Server (NTRS)
Dyall, Kenneth G.; Faegri, Knut, Jr.
1993-01-01
The effect of using a finite nucleus model in quantum-chemical calculations is examined. Relativistic corrections from the first order Foldy-Wouthuysen terms are affected indirectly by the change in wavefunction, but also directly as a result of revised expressions for the Darwin and spin-orbit terms due to the change in nuclear potential. A calculation for the Rn atom indicates that the mass-velocity and Darwin corrections are much more sensitive to the finite nucleus than the non-relativistic total energy, but that the total contribution for these two terms is quite stable provided the revised form of the Darwin term is used. The spin-orbit interaction is not greatly affected by the choice of nuclear model.
Isospin flip as a relativistic effect: NN interactions
NASA Technical Reports Server (NTRS)
Buck, W. W.
1993-01-01
Results are presented of an analytic relativistic calculation of a OBE nucleon-nucleon (NN) interaction employing the Gross equation. The calculation consists of a non-relativistic reduction that keeps the negative energy states. The result is compared to purely non-relativistic OBEP results and the relativistic effects are separated out. One finds that the resulting relativistic effects are expressable as a power series in (tau(sub 1))(tau(sub 2)) that agrees, qualitatively, with NN scattering. Upon G-parity transforming this NN potential, one obtains, qualitatively, a short range NN spectroscopy in which the S-states are the lowest states.
Magnetogenesis through a Relativistic Biermann Effect
NASA Astrophysics Data System (ADS)
Miller, Evan
2012-10-01
In a 2010 Physical Review Letter, Mahajan and Yoshida proposed a relativistic correction to the well-known Biermann Battery. The Biermann Battery allows for the generation of magnetic fields in a plasma fluid from orthogonal gradients in temperature and entropy (Bt ∇T x∇σ). The proposed correction would result in an additional term, proportional to the gradient of velocity squared crossed with the gradient of entropy (Bt ∇v^2 x∇σ). This new effect can in some cases provide the dominate source of magnetic field growth, even when the fluid is only mildly relativistic. This could in turn help explain the dynamics of certain relativistic plasmas, including modern laser plasmas and astrophysical jets. It is possible it could even provide a primordial source for the seed fields needed to explain the cosmological magnetic fields that appear to permeate most galaxies. In my poster, I will explain the theory underlying this new correction and present simulations demonstrating magnetic field growth in a variety of test cases, performed using both a particle-in-cell code and a fluid model.
Relativistic Effects Break Periodicity in Group 6 Diatomic Molecules.
Wang, Yi-Lei; Hu, Han-Shi; Li, Wan-Lu; Wei, Fan; Li, Jun
2016-02-01
The finding of the periodic law is a milestone in chemical science. The periodicity of light elements in the Periodic Table is fully accounted for by quantum mechanics. Here we report that relativistic effects change the bond multiplicity of the group 6 diatomic molecules M2 (M = Cr, Mo, W, Sg) from hextuple bonds for Cr2, Mo2, W2 to quadruple bonds for Sg2, thus breaking the periodicity in the nonrelativistic domain. The same trend is also found for other superheavy-element diatomics Rf2, Db2, Bh2, and Hs2. PMID:26787134
Relativistic treatment of inertial spin effects
NASA Astrophysics Data System (ADS)
Ryder, Lewis
1998-03-01
A relativistic spin operator for Dirac particles is identified and it is shown that a coupling of spin to angular velocity arises in the relativistic case, just as Mashhoon had speculated, and Hehl and Ni had demonstrated, in the non-relativistic case.
Relativistic effects on atomic and molecular properties of the heaviest elements
NASA Astrophysics Data System (ADS)
Pershina, V.; Anton, J.; Bastug, T.
2007-10-01
Interaction of superheavy element 112 and its homolog Hg with inert and gold surfaces was studied on the basis of atomic and molecular fully-relativistic (4-component) DFT electronic structure calculations. Performance of additional non-relativistic calculations allowed one to demonstrate the role and magnitude of relativistic effects on adsorption energies and bond distances of the studied systems. For example, on quartz, element 112 will be stronger adsorbed than Hg by about 5 kJ/mol (or at 5 degrees higher temperatures) due to the stronger van der Waals interaction. This is caused by the relativistically contracted smallest atomic radius of element 112. Non-relativistically, the trend would be opposite. On surface of gold, element 112 will be about 20 kJ/mol weaker adsorbed than Hg (i.e., it will be deposited at about 100 degrees lower temperatures than Hg). Such a decrease in Δ Hads comes at the account of the weaker interaction of the relativistically stabilized 7s1/2(112) orbital with valence orbitals of gold. Still, the relatively large adsorption energy of element 112 is indicative that it is a transition metal forming intermetallic compounds with Au and other metals due to the involvement of the relativistically destabilized 6d orbitals. The influence of relativistic effects on the adsorption energy depends, however, on the adsorption position.
Formulation of the relativistic quantum Hall effect and parity anomaly
NASA Astrophysics Data System (ADS)
Yonaga, Kouki; Hasebe, Kazuki; Shibata, Naokazu
2016-06-01
We present a relativistic formulation of the quantum Hall effect on Haldane sphere. An explicit form of the pseudopotential is derived for the relativistic quantum Hall effect with/without mass term. We clarify particular features of the relativistic quantum Hall states with the use of the exact diagonalization study of the pseudopotential Hamiltonian. Physical effects of the mass term to the relativistic quantum Hall states are investigated in detail. The mass term acts as an interpolating parameter between the relativistic and nonrelativistic quantum Hall effects. It is pointed out that the mass term unevenly affects the many-body physics of the positive and negative Landau levels as a manifestation of the "parity anomaly." In particular, we explicitly demonstrate the instability of the Laughlin state of the positive first relativistic Landau level with the reduction of the charge gap.
Relativistic effects in nuclear many-body systems
Coester, F.
1985-01-01
Different approaches to the formulation of relativistic many-body dynamics yield different perspectives of nature and the magnitude of ''relativistic effects''. The effects of Lorentz invariance appear to be relatively unimportant. Important dynamical features of spinorial many-body formalisms are effects of subnuclear degrees of freedom which are represented in the many-body forces of the covariant nuclear Hamiltonian. 24 refs.
Tensor coupling effect on relativistic symmetries
NASA Astrophysics Data System (ADS)
Chen, ShouWan; Li, DongPeng; Guo, JianYou
2016-08-01
The similarity renormalization group is used to transform the Dirac Hamiltonian with tensor coupling into a diagonal form. The upper (lower) diagonal element becomes a Schr¨odinger-like operator with the tensor component separated from the original Hamiltonian. Based on the operator, the tensor effect of the relativistic symmetries is explored with a focus on the single-particle energy contributed by the tensor coupling. The results show that the tensor coupling destroying (improving) the spin (pseudospin) symmetry is mainly attributed to the coupling of the spin-orbit and the tensor term, which plays an opposite role in the single-particle energy for the (pseudo-) spin-aligned and spin-unaligned states and has an important influence on the shell structure and its evolution.
Compton Effect with Non-Relativistic Kinematics
ERIC Educational Resources Information Center
Shivalingaswamy, T.; Kagali, B. A.
2011-01-01
In deducing the change of wavelength of x-rays scattered by atomic electrons, one normally makes use of relativistic kinematics for electrons. However, recoiling energies of the electrons are of the order of a few keV which is less than 0.2% of their rest energies. Hence the authors may ask whether relativistic formulae are really necessary. In…
Stabilization effect of Weibel modes in relativistic laser fusion plasma
NASA Astrophysics Data System (ADS)
Belghit, Slimen; Sid, Abdelaziz
2016-06-01
In this work, the Weibel instability (WI) due to inverse bremsstrahlung (IB) absorption in a laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by WI with the laser wave field is explicitly shown. In this study, the relativistic effects are taken into account. Here, the basic equation is the relativistic Fokker-Planck (F-P) equation. The main obtained result is that the coupling of self-generated magnetic field with the laser wave causes a stabilizing effect of excited Weibel modes. We found a decrease in the spectral range of Weibel unstable modes. This decreasing is accompanied by a reduction of two orders in the growth rate of instable Weibel modes or even stabilization of these modes. It has been shown that the previous analysis of the Weibel instability due to IB has overestimated the values of the generated magnetic fields. Therefore, the generation of magnetic fields by the WI due to IB should not affect the experiences of an inertial confinement fusion.
NASA Technical Reports Server (NTRS)
Bauschlicher, C. W., Jr.; Jaffe, R. L.; Langhoff, S. R.; Partridge, H.; Mascarello, F. G.
1985-01-01
Theoretical calculations of selected excitation energies and oscillator strengths for Ba are presented that overcome the difficulties of previous theoretical treatments. A relativistic effective-core potential treatment is used to account for the relativistic core contraction, but the outermost ten electrons are treated explicitly. Core-valence correlation can be included in this procedure in a rigorous and systematic way through a configuration-interaction calculation. Insight is gained into the importance of relativistic effects by repeating many of the calculations using an all-electron nonrelativistic treatment employing an extended Slater basis set. It is found that the intensity of the intercombination line 3P1-1S0 is accurately determined by accounting for the deviation from LS coupling through spin-orbit mixing with the 1P1 state, and that deviations from the Lande interval rule provide an accurate measure of the degree of mixing.
Large-scale imprint of relativistic effects in the cosmic magnification
NASA Astrophysics Data System (ADS)
Duniya, Didam G. A.
2016-05-01
Apart from the known weak gravitational lensing effect, the cosmic magnification acquires relativistic corrections owing to Doppler, integrated Sachs-Wolfe, time-delay and other (local) gravitational potential effects, respectively. These corrections grow on very large scales and high redshifts z , which will be the reach of forthcoming surveys. In this work, these relativistic corrections are investigated in the magnification angular power spectrum, using both (standard) noninteracting dark energy (DE), and interacting DE (IDE). It is found that for noninteracting DE, the relativistic corrections can boost the magnification large-scale power by ˜40 % at z =3 , and increases at lower z . It is also found that the IDE effect is sensitive to the relativistic corrections in the magnification power spectrum, particularly at low z —which will be crucial for constraints on IDE. Moreover, the results show that if relativistic corrections are not taken into account, this may lead to an incorrect estimate of the large-scale imprint of IDE in the cosmic magnification; including the relativistic corrections can enhance the true potential of the cosmic magnification as a cosmological probe.
Lorentz symmetry breaking effects on relativistic EPR correlations
NASA Astrophysics Data System (ADS)
Belich, H.; Furtado, C.; Bakke, K.
2015-09-01
Lorentz symmetry breaking effects on relativistic EPR (Einstein-Podolsky-Rosen) correlations are discussed. From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the Lorentz symmetry violation and write an effective metric for the Minkowski spacetime. Then we obtain the Wigner rotation angle via the Fermi-Walker transport of spinors and consider the WKB (Wentzel-Kramers-Brillouin) approximation in order to study the influence of Lorentz symmetry breaking effects on the relativistic EPR correlations.
Tupitsyn, I.I.
1988-03-01
The ionization potentials of the halogen group have been calculated. The calculations were carried out using the relativistic Hartree-Fock method taking into account correlation effects. Comparison of theoretical results with experimental data for the elements F, Cl, Br, and I allows an estimation of the accuracy and reliability of the method. The theoretical values of the ionization potential of astatine obtained here may be of definite interest for the chemistry of astatine.
Relativistic and quantum electrodynamic effects in superheavy elements
NASA Astrophysics Data System (ADS)
Schwerdtfeger, Peter; Pašteka, Lukáš F.; Punnett, Andrew; Bowman, Patrick O.
2015-12-01
The current status of relativistic electronic structure theory for superheavy elements is reviewed. Recent developments in relativistic quantum theory have made it possible to obtain accurate electronic properties for the trans-actinide elements with the aim to predict their chemical and physical behaviour. The role of quantum electrodynamic effects beyond the no-virtual-pair approximation, which is usually neglected in relativistic molecular calculations, is discussed. Changes in periodic trends due to relativistic effects are outlined for the superheavy elements with nuclear charge Z = 111- 120. We also analyse the role of the negative energy states for the electronic stability of superheavy elements beyond the critical nuclear charge (Zcrit ≈ 170), where the 1s state enters the negative energy continuum at - 2mec2.
Effects of retardation in relativistic equations with confining interaction
NASA Technical Reports Server (NTRS)
Maung, Khin Maung; Kahana, David E.; Norbury, John W.
1992-01-01
A method has been developed for solving two body relativistic bound state equations in momentum space with a confining interaction. A total of six different three dimensional reductions of the Bethe-Salpeter equations are studied with particular emphasis placed on the competing roles of relativistic kinematics and retardation. The results indicate that these two effects counteract each other and this sheds some light on why nonrelativistic models of meson spectroscopy have been quite successful.
Relativistic effects on nonlinear lower hybrid oscillations in cold plasma
Maity, Chandan; Chakrabarti, Nikhil
2011-04-15
Nonlinear lower hybrid mode in a quasineutral magnetized plasma is analyzed in one space dimension using Lagrangian coordinates. In a cold fluid, we treat electron fluid relativistically, whereas ion fluid nonrelativistically. The homotopy perturbation method is employed to obtain the nonlinear solution which also finds the frequency-amplitude relationship for the lower hybrid mode. The solution indicates that the amplitude of oscillation increases due to the weak relativistic effects. The appearance of density spikes is not ruled out in a magnetized plasma.
One-pion exchange current effects on magnetic form factor in the relativistic formalism
NASA Astrophysics Data System (ADS)
Zhang, Cun; Liu, Jian; Ren, Zhongzhou
2016-08-01
One-pion exchange current effects on the magnetic form factors of some odd nuclei are studied in the relativistic formalism. The Dirac wave functions of nucleons are calculated from the relativistic mean-field theory. After fitting to experimental data by quenching factors, it is found that taking the one-pion exchange currents into account gives a better description of the magnetic form factor. The root-mean-square radii of the valance nucleon orbits are also calculated in RMF model, which coincide with experimental radii extracted with meson exchange current corrections.
Relativistic effects on information measures for hydrogen-like atoms
NASA Astrophysics Data System (ADS)
Katriel, Jacob; Sen, K. D.
2010-01-01
Position and momentum information measures are evaluated for the ground state of the relativistic hydrogen-like atoms. Consequences of the fact that the radial momentum operator is not self-adjoint are explicitly studied, exhibiting fundamental shortcomings of the conventional uncertainty measures in terms of the radial position and momentum variances. The Shannon and Rényi entropies, the Fisher information measure, as well as several related information measures, are considered as viable alternatives. Detailed results on the onset of relativistic effects for low nuclear charges, and on the extreme relativistic limit, are presented. The relativistic position density decays exponentially at large r, but is singular at the origin. Correspondingly, the momentum density decays as an inverse power of p. Both features yield divergent Rényi entropies away from a finite vicinity of the Shannon entropy. While the position space information measures can be evaluated analytically for both the nonrelativistic and the relativistic hydrogen atom, this is not the case for the relativistic momentum space. Some of the results allow interesting insight into the significance of recently evaluated Dirac-Fock vs. Hartree-Fock complexity measures for many-electron neutral atoms.
Relativistic effects for low Earth orbit satellites using GPS
NASA Astrophysics Data System (ADS)
Spallicci, A.; Jimenez, C.; Prisco, G.; Ashby, N.
1992-06-01
The relativistic corrections for a low Earth orbit satellite are evaluated. The GPS (Global Positioning System) satellite clock rate is slowed before launch by 4.465 x 10(exp -10), called the 'factory offset', for time dilation and gravitational frequency shift. This offset cancels the main constant relativistic effects for terrestrial users, which in order to operate in coordinate time have only to process the GPS orbital eccentricities, a sinusoidal function whose peaks are in the order of tens of ns, and the Sagnac effect. For a space user the situation greatly differs, because a large part of the relativistic effects are still present due to the high velocity of the satellite and its location in the Earth gravitational field. Past tests and proposals for future measurements with GPS--perigee advance, Shapiro time delay, preferred frame independence, Lense Thirring effect, light bending and gravitational waves--are reviewed.
Bučinský, Lukáš; Jayatilaka, Dylan; Grabowsky, Simon
2016-08-25
This study investigates the possibility of detecting relativistic effects and electron correlation in single-crystal X-ray diffraction experiments using the examples of diphenyl mercury (HgPh2) and triphenyl bismuth (BiPh3). In detail, the importance of electron correlation (ECORR), relativistic effects (REL) [distinguishing between total, scalar and spin-orbit (SO) coupling relativistic effects] and picture change error (PCE) on the theoretical electron density, its topology and its Laplacian using infinite order two component (IOTC) wave functions is discussed. This is to develop an understanding of the order of magnitude and shape of these different effects as they manifest in the electron density. Subsequently, the same effects are considered for the theoretical structure factors. It becomes clear that SO and PCE are negligible, but ECORR and scalar REL are important in low- and medium-order reflections on absolute and relative scales-not in the high-order region. As a further step, Hirshfeld atom refinement (HAR) and subsequent X-ray constrained wavefunction (XCW) fitting have been performed for the compound HgPh2 with various relativistic and nonrelativistic wave functions against the experimental structure factors. IOTC calculations of theoretical structure factors and relativistic HAR as well as relativistic XCW fitting are presented for the first time, accounting for both scalar and spin-orbit relativistic effects. PMID:27434184
Relativistic Effects on Reflection X-ray Spectra of AGN
Lee, Khee-Gan; Fuerst, Steven V.; Brandwardi-Raymond, Graziella; Wu, Kinwah; Crowley, Oliver; /University Coll. London
2007-01-05
We have calculated the reflection component of the X-ray spectra of active galactic nuclei (AGN) and shown that they can be significantly modified by the relativistic motion of the accretion flow and various gravitational effects of the central black hole. The absorption edges in the reflection spectra suffer severe energy shifts and smearing. The degree of distortion depends on the system parameters, and the dependence is stronger for some parameters such as the inner radius of the accretion disk and the disk viewing inclination angles. The relativistic effects are significant and are observable. Improper treatment of the reflection component of the X-ray continuum in spectral fittings will give rise to spurious line-like features, which will mimic the fluorescent emission lines and mask the relativistic signatures of the lines.
Relativistic Effects on the Radial Equilibrium of Nonneutral Plasmas
Rome, M.; Pozzoli, R.; Kotelnikov, I.
2009-03-30
Relativistic effects on the radial equilibrium of nonneutral plasmas confined in cylindrical traps are analyzed for rigid and sheared modes of plasma rotation, both with and without the presence of a coaxial inner charged conductor. The changes with respect to the non-relativistic results are especially pronounced for the fast rotational equilibrium solutions. In particular, relativistic effects can limit the plasma outer radius. Analytical estimates of this maximum radius are found both for a rigid plasma rotation and for the case of a uniform plasma density. It is also observed that the Brillouin density limit is modified when the shielding of the external magnetic field by the current associated with the plasma rotation becomes significant.
Cyclotron resonance in topological insulators: non-relativistic effects
NASA Astrophysics Data System (ADS)
Tabert, C. J.; Carbotte, J. P.
2015-09-01
The low-energy Hamiltonian used to describe the dynamics of the helical Dirac fermions on the surface of a topological insulator contains a subdominant non-relativistic (Schrödinger) contribution. This term can have an important effect on some properties while having no effect on others. The Hall plateaus retain the same relativistic quantization as the pure Dirac case. The height of the universal interband background conductivity is unaltered, but its onset is changed. However, the non-relativistic term leads directly to particle-hole asymmetry. It also splits the interband magneto-optical lines into doublets. Here, we find that, while the shape of the semiclassical cyclotron resonance line is unaltered, the cyclotron frequency and its optical spectral weight are changed. There are significant differences in both of these quantities for a fixed value of chemical potential or fixed doping away from charge neutrality depending on whether the Fermi energy lies in the valence or conduction band.
Effective photon mass and exact translating quantum relativistic structures
NASA Astrophysics Data System (ADS)
Haas, Fernando; Manrique, Marcos Antonio Albarracin
2016-04-01
Using a variation of the celebrated Volkov solution, the Klein-Gordon equation for a charged particle is reduced to a set of ordinary differential equations, exactly solvable in specific cases. The new quantum relativistic structures can reveal a localization in the radial direction perpendicular to the wave packet propagation, thanks to a non-vanishing scalar potential. The external electromagnetic field, the particle current density, and the charge density are determined. The stability analysis of the solutions is performed by means of numerical simulations. The results are useful for the description of a charged quantum test particle in the relativistic regime, provided spin effects are not decisive.
Correlation and relativistic effects in actinide ions
Safronova, U. I.; Safronova, M. S.
2011-11-15
Wavelengths, line strengths, and transition rates are calculated for the multipole (E1, M1, E2, M2, E3, and M3) transitions between the excited 6s{sup 2}6p{sup 5}nl and 6s6p{sup 6}nl states and the ground 6s{sup 2}6p{sup 6} state in Ac{sup 3+}, Th{sup 4+}, and U{sup 6+} Rn-like ions. Relativistic many-body perturbation theory (RMBPT), including the Breit interaction, is used to evaluate energies and transition rates for multipole transitions in these hole-particle systems. The RMBPT method agrees with multiconfigurational Dirac-Fock (MCDF) calculations in lowest order, includes all second-order correlation corrections, and includes corrections from negative-energy states. The calculations start from a [Xe]4f{sup 14}5d{sup 10}6s{sup 2}6p{sup 6} Dirac-Fock potential. First-order perturbation theory is used to obtain intermediate-coupling coefficients, and second-order RMBPT is used to determine the matrix elements. Evaluated multipole matrix elements for transitions from excited states to the ground states are used to determine the line strengths, transition rates, and multipole polarizabilities. This work provides a number of yet unmeasured properties of these actinide ions for various applications and for benchmark tests of theory and experiment.
NASA Astrophysics Data System (ADS)
Bödeker, Dietrich; Wörmann, Mirco
2014-02-01
In many phenomenologically interesting models of thermal leptogenesis the heavy neutrinos are non-relativistic when they decay and produce the baryon asymmetry of the Universe. We propose a non-relativistic approximation for the corresponding rate equations in the non-resonant case, and a systematic way for computing relativistic corrections. We determine the leading order coefficients in these equations, and the first relativistic corrections. The non-relativistic approximation works remarkably well. It appears to be consistent with results obtained using a Boltzmann equation taking into account the momentum distribution of the heavy neutrinos, while being much simpler. We also compute radiative corrections to some of the coefficients in the rate equations. Their effect is of order 1% in the regime favored by neutrino oscillation data. We obtain the correct leading order lepton number washout rate in this regime, which leads to large ( ~ 20%) effects compared to previous computations.
The effect of direct positron production on relativistic feedback rates
NASA Astrophysics Data System (ADS)
Vodopiyanov, I. B.; Dwyer, J. R.; Lucia, R. J.; Cramer, E. S.; Arabshahi, S.; Rassoul, H.
2013-12-01
Relativistic feedback produces a self-sustaining runaway electron discharge via the production of backward propagating positrons and back-scattered x-rays. To date, only positrons created from pair-production by gamma-rays interacting with the air have been considered. In contrast, direct pair-production involves the creation of electron-positron pairs directly from the interaction of energetic runaway electrons with nuclei, and so it does not require the generation of bremsstrahlung gamma-rays. For high electric fields, where the runaway electron avalanche length scales are short, pair-production involving bremsstrahlung gamma-rays makes a smaller contribution to the total relativistic feedback rates than at lower fields, since both the bremsstrahlung interaction and the pair-production need to occur over a short length. On the other hand, for high fields, because direct positron production only involves one interaction, it may make a significant contribution to relativistic feedback rates in some cases. In this poster, we shall present the direct positron production cross-sections and calculate the effects on the relativistic feedback rates due to this process.
Relativistic Effects in Chemistry: More Common Than You Thought
NASA Astrophysics Data System (ADS)
Pyykkö, Pekka
2012-05-01
Relativistic effects can strongly influence the chemical and physical properties of heavy elements and their compounds. This influence has been noted in inorganic chemistry textbooks for a couple of decades. This review provides both traditional and new examples of these effects, including the special properties of gold, lead-acid and mercury batteries, the shapes of gold and thallium clusters, heavy-atom shifts in NMR, topological insulators, and certain specific heats.
Effects of trapping and finite temperature in a relativistic degenerate plasma
Shah, H. A.; Qureshi, M. N. S.; Masood, W.; Tsintsadze, N. L.
2011-10-15
In the present work, we have undertaken, for the first time, investigation on the effect of trapping on the formation of solitary structures in relativistic degenerate plasmas. Such plasmas have been observed in dense astrophysical objects, and in laboratory these may result due to the interaction of intense lasers with matter. We have used the relativistic Fermi-Dirac distribution to describe the dynamics of the degenerate trapped electrons by solving the kinetic equation. The Sagdeev potential approach has been employed to obtain the arbitrary amplitude solitary structures both when the plasma has been considered cold and when small temperature effects have been taken into account. The theoretical results obtained have been analyzed numerically for different parameter values, and the results have been presented graphically.
Relativistic AC gyromagnetic effects in ultraintense laser-matter interaction.
Geindre, J P; Audebert, P; Marjoribanks, R S
2006-08-25
We demonstrate that in ultraintense ultrafast laser-matter interaction, the interplay of laser-induced oscillating space-charge fields with laser E and B fields can strongly affect whether the interaction is relativistic or not: stronger laser fields may not in fact produce more relativistic plasma interactions. We show that there exists a regime of interaction, in the relation of laser intensity and incident angle, for which the Brunel effect of electron acceleration is strongly suppressed by AC gyromagnetic fields, at a frequency different from the laser field. Analytically and with 1.5D particle-in-cell modeling, we show that from gyromagnetic effects, even in the absence of usual J x B second-harmonic contributions, there are strong effects on the harmonic emission and on the generation of attosecond pulses. PMID:17026310
Relativistic effects in galaxy clustering in a parametrized post-Friedmann universe
NASA Astrophysics Data System (ADS)
Lombriser, Lucas; Yoo, Jaiyul; Koyama, Kazuya
2013-05-01
We explore the signatures of quintessence and modified gravity theories in the relativistic description of galaxy clustering within a parametrized post-Friedmann framework. For this purpose, we develop a calibration method to consistently account for horizon-scale effects in the linear parametrized post-Friedmann perturbations of minimally and nonminimally coupled scalar-tensor theories and test it against the full model-specific fluctuations. We further study the relativistic effects in galaxy clustering for the normal and self-accelerating branches of the Dvali-Gabadadze-Porrati braneworld model as well as for phenomenological modifications of gravity. We quantify the impact of modified gravity and dark energy models on galaxy clustering by computing the velocity-to-matter density ratio F, the velocity contribution R, and the potential contribution P and give an estimate of their detectability in future galaxy surveys. Our results show that, in general, the relativistic correction contains additional information on gravity and dark energy, which needs to be taken into account in consistent horizon-scale tests of departures from ΛCDM using the galaxy-density field.
The nonlinear effect in relativistic Compton scattering for an intense circularly polarized laser
NASA Astrophysics Data System (ADS)
Luo, W.; Zhuo, H. B.; Ma, Y. Y.; Zhu, Z. C.; Fan, G. T.; Xu, W.; Song, Y. M.
2014-07-01
Compton scattering between an intense laser pulse and a relativistic electron beam offers a promising development path toward high-energy, high-brightness x- and gamma-ray sources. Increasing laser peak power to obtain intense x- and gamma rays causes nonlinear Compton scattering to occur. To predict high-order harmonic radiation properties, we upgrade a Monte Carlo laser-Compton scattering simulation code (MCLCSS) by taking into account the nonlinear effect for the relativistic Compton scattering process. The energy spectra and angular and harmonic intensity distributions of the scattered photons are investigated using nonlinear Compton scattering of an intense circularly polarized laser. It is found that the laser parameter {{a}_{0}}\\equiv e{\\rm{A}}\\;{{m}_{e}}{{c}^{-2}} plays an important role in the generation of high-order harmonic radiation. Our study also suggests that the high-energy tails of the second and higher harmonics will stray from the backscattering region.
Angular dependence of Wigner time delay: Relativistic Effects
NASA Astrophysics Data System (ADS)
Mandal, A.; Deshmukh, P. C.; Manson, S. T.; Kkeifets, A. S.
2016-05-01
Laser assisted photoionization time delay mainly consists of two parts: Wigner time delay, and time delay in continuum-continuum transition. Wigner time delay results from the energy derivative of the phase of the photoionization amplitude (matrix element). In general, the photoionization time delay is not the same in all directions relative to the incident photon polarization, although when a single transition dominates the amplitude, the resultant time delay is essentially isotropic. The relativistic-random-phase approximation is employed to determine the Wigner time delay in photoionization from the outer np subshells of the noble gas atoms, Ne through Xe. The time delay is found to significantly depend on angle, as well as energy. The angular dependence of the time delay is found to be quite sensitive to atomic dynamics and relativistic effects, and exhibit strong energy and angular variation in the neighborhood of Cooper minima. Work supported by DOE, Office of Chemical Sciences and DST (India).
RANDOM WALKS AND EFFECTIVE OPTICAL DEPTH IN RELATIVISTIC FLOW
Shibata, Sanshiro; Tominaga, Nozomu; Tanaka, Masaomi
2014-05-20
We investigate the random walk process in relativistic flow. In the relativistic flow, photon propagation is concentrated in the direction of the flow velocity due to the relativistic beaming effect. We show that in the pure scattering case, the number of scatterings is proportional to the size parameter ξ ≡ L/l {sub 0} if the flow velocity β ≡ v/c satisfies β/Γ >> ξ{sup –1}, while it is proportional to ξ{sup 2} if β/Γ << ξ{sup –1}, where L and l {sub 0} are the size of the system in the observer frame and the mean free path in the comoving frame, respectively. We also examine the photon propagation in the scattering and absorptive medium. We find that if the optical depth for absorption τ{sub a} is considerably smaller than the optical depth for scattering τ{sub s} (τ{sub a}/τ{sub s} << 1) and the flow velocity satisfies β≫√(2τ{sub a}/τ{sub s}), then the effective optical depth is approximated by τ{sub *} ≅ τ{sub a}(1 + β)/β. Furthermore, we perform Monte Carlo simulations of radiative transfer and compare the results with the analytic expression for the number of scatterings. The analytic expression is consistent with the results of the numerical simulations. The expression derived in this study can be used to estimate the photon production site in relativistic phenomena, e.g., gamma-ray burst and active galactic nuclei.
How Do The Relativistic Effects Effect the Appearance of a Clothed Black Hole?
NASA Technical Reports Server (NTRS)
Zhang, Xiaoling; Zhang, S. N.; Feng, Yuxin; Yao, Yangsen
2002-01-01
For an accretion disk around a black hole, the strong relativistic effects affect every aspect of the radiation from the disk, including the spectrum, the light-curve, and the image. If the disk is in high inclination angle (nearly edge-on), the image will be greatly distorted; the farther side of the disk will appear to bend toward the observer, photons from the other side of the disk can reach the observer (if they are not blocked by the disk) to form a ghost image. This work differs mainly from previous work by taking into account the temperature distribution of a standard thin disk model and investigating the expected images from different viewing angles and in different energy bands. The edge-blocking effect is also considered. Direct images of black hole systems may be obtained with future X-ray missions like MAXIM pathfinder.
Effects of Preplasma in 10-ps Relativistic Laser Matter Interaction
NASA Astrophysics Data System (ADS)
Wei, M. S.; Stephens, R. B.; Peebles, J.; McGuffey, C.; Qiao, B.; Beg, F.; Sentoku, Y.; Link, A.; Chen, H.; McLean, H.; Theobald, W.; Haberberger, D.; Davies, A.
2014-10-01
Experiments were performed using the kJ 10-ps OMEGA EP laser to study the effect of preplasma on fast electron generation and energy coupling in relativistic laser plasma interaction (LPI) with a controlled preplasma at various scalelength created by a 1-ns UV laser. Targets were multilayered planar foil consisting of an Al substrate, a buried Cu layer and a thick conductive CH layer. Preplasma density profile and relativistic LPI generated fields were characterized using a 10-ps 4 ω optical probe (angular filter refractometry and polarimetry) together with radiography using a high-energy proton beam produced by the second kJ 10-ps EP beam. Fast electrons were diagnosed by measuring Cu K-shell fluorescence emission and bremsstrahlung radiation. Electron energy spectrum was monitored by a magnetic spectrometer. Preliminary results showed nonlinear interaction instabilities and a reduced electron temperature with increasing preplasma scalelength. Dynamics of the relativistic LPI and the resultant fast electron beam characteristics and energy coupling will be presented. Supported by the US DOE under DE-NA0002026 and DE-FC02-04ER54789.
Rusakova, Irina L; Rusakov, Yury Yu; Krivdin, Leonid B
2016-06-01
This work reports on the comprehensive calculation of the NMR one-bond spin-spin coupling constants (SSCCs) involving carbon and tellurium, (1) J((125) Te,(13) C), in four representative compounds: Te(CH3 )2 , Te(CF3 )2 , Te(CCH)2 , and tellurophene. A high-level computational treatment of (1) J((125) Te,(13) C) included calculations at the SOPPA level taking into account relativistic effects evaluated at the 4-component RPA and DFT levels of theory, vibrational corrections, and solvent effects. The consistency of different computational approaches including the level of theory of the geometry optimization of tellurium-containing compounds, basis sets, and methods used for obtainig spin-spin coupling values have also been discussed in view of reproducing the experimental values of the tellurium-carbon SSCCs. Relativistic corrections were found to play a major role in the calculation of (1) J((125) Te,(13) C) reaching as much as almost 50% of the total value of (1) J((125) Te,(13) C) while relativistic geometrical effects are of minor importance. The vibrational and solvent corrections account for accordingly about 3-6% and 0-4% of the total value. It is shown that taking into account relativistic corrections, vibrational corrections and solvent effects at the DFT level essentially improves the agreement of the non-relativistic theoretical SOPPA results with experiment. © 2016 Wiley Periodicals, Inc. PMID:26931355
Relativistic stellar stability: Preferred-frame effects
NASA Technical Reports Server (NTRS)
Ni, W.
1973-01-01
Possible preferred-frame effects on stellar stability were examined and no new instabilities were found. In particular, it is shown that: (1) Although terms linear in the preferred-frame velocity w (time-odd terms, analogous to viscosity and energy generation) change the shapes of the normal modes, their symmetry properties prevent them from changing the characteristic frequencies. Thus, no new vibrational or secular instabilities can occur. (2) Terms quadratic in w do not change either the shapes of the normal modes or the characteristic frequencies for radial pulsations. Thus, they have no influence on radial stability. (3) Terms quadratic in w do change both the normal modes and the characteristic frequencies of nonradial pulsations; but in the limit of a neutral mode these changes vanish. Hence, there is no modification of the criterion for convective stability, i.e., the standard Schwarzschild criterion remains valid.
Relativistic Beaming Effect in Fermi Blazars
NASA Astrophysics Data System (ADS)
Fan, J. H.; Bastieri, D.; Yang, J. H.; Liu, Y.; Wu, D. X.; Li, S. H.
2014-09-01
The most identified sources observed by Fermi/LAT are blazars, based on which we can investigate the emission mechanisms and beaming effect in the γ-ray bands for blazars. Here, we used the compiled around 450 Fermi blazars with the available X-ray observations to estimate their Doppler factors and compared them with the integral γ-ray luminosity in the range of 1-100 GeV. It is interesting that the integral γ-ray luminosity is closely correlated with the estimated Doppler factor, for the whole sample. When the dependence of the correlation between them and the X-ray luminosity is removed, the correlation is still strong, which suggests that the γ-ray emissions are strongly beamed.
Lehner, T; di Menza, L
2002-01-01
Nonlinear equations are derived relevant to describe the propagation of powerful electromagnetic fields launched within a plasma. The nonlinear generation of self-induced collective electromagnetic perturbations are obtained with matter lying in the relativistic regime. Our main result is the self-consistent treatment of the coupled equations between the pump and its self-induced fields. In particular, a mechanism is pointed out for self-generation of quasistatic magnetic field that is due to the relativistic ponderomotive force. This process is found to be more efficient to produce quasistatic magnetic fields, as confirmed by recent experiments, as compared to known effects such as the inverse Faraday effect. As an application, we investigate conditions for relativistic magnetic guiding of light to occur under the combined action of the self-induced density and magnetic field. PMID:11800797
NASA Astrophysics Data System (ADS)
Roura, P. G.; Melo, J. I.; Ruiz de Azúa, M. C.; Giribet, C. G.
2006-08-01
The linear response within the elimination of the small component formalism is aimed at obtaining the leading order relativistic corrections to magnetic molecular properties in the context of the elimination of the small component approximation. In the present work we extend the method in order to include two-body effects in the form of a mean field one-body operator. To this end we consider the four-component Dirac-Hartree-Fock operator as the starting point in the evaluation of the second order relativistic expression of magnetic properties. The approach thus obtained is the fully consistent leading order approximation of the random phase approximation four-component formalism. The mean field effect on the relativistic corrections to both the diamagnetic and paramagnetic terms of magnetic properties taking into account both the Coulomb and Breit two-body interactions is considered.
Bokaei, B.; Niknam, A. R.
2014-10-15
The spatiotemporal dynamics of high power laser pulses in near critical plasmas are studied taking in to account the effects of relativistic and ponderomotive nonlinearities. First, within one-dimensional analysis, the effects of initial parameters such as laser intensity, plasma density, and plasma electron temperature on the self-compression mechanism are discussed. The results illustrate that the ponderomotive nonlinearity obstructs the relativistic self-compression above a certain intensity value. Moreover, the results indicate the existence of the turning point temperature in which the compression process has its strongest strength. Next, the three-dimensional analysis of laser pulse propagation is investigated by coupling the self-focusing equation with the self-compression one. It is shown that in contrast to the case in which the only relativistic nonlinearity is considered, in the presence of ponderomotive nonlinearity, the self-compression mechanism obstructs the self-focusing and leads to an increase of the laser spot size.
QED effects and radiation generation in relativistic laser plasma
NASA Astrophysics Data System (ADS)
Kostyukov, I. Yu.; Nerush, E. N.; Bashmakov, V. F.
2011-06-01
The radiative and quantum effects in laser plasmas are discussed. The self-consistent numerical model based on particle-in-cell and Monte-Carlo methods are developed. First we analyze the spectra of Compton backscattered photons and betatron radiation in the classical and quantum regimes. Then we address an interaction between intense laser pulse and relativistic electron beam. Finally we discuss the electron-positron pair plasma production in extremely-intense laser field. It is shown that such plasma can be an efficient source of energetic gammaquanta.
The Relaxation Effect in Dissipative Relativistic Fluid Theories
NASA Astrophysics Data System (ADS)
Lindblom, Lee
1996-04-01
The dynamics of the fluid fields in a large class of causal dissipative fluid theories is studied. It is shown that the physical fluid states in these theories must relax (on a time scale that is characteristic of the microscopic particle interactions) to ones that are essentially indistinguishable from the simple relativistic Navier-Stokes descriptions of these states. Thus, for example, in the relaxed form of a physical fluid state the stress energy tensor is in effect indistinguishable from a perfect fluid stress tensor plus small dissipative corrections proportional to the shear of the fluid velocity, the gradient of the temperature, etc.
Relativistic Effects Around Black Holes: Smearing Absorption Edges
NASA Technical Reports Server (NTRS)
Zhang, X. L.; Feng, Y. X.; Zhang, S. N.; Yao, Y.
2002-01-01
Broad iron absorption structures have been observed in the X-ray spectra of both AGNs and black hole X-ray binaries (BHXBs). A correctly modeled absorption structure can reveal the physical condition of the source, help to determine the continuum spectra and thus help to estimate other spectral lifes more accurately. The absorption structures are usually thought to be caused by the reflection of X-rays by the accretion disks around the central black holes, and the broadening can be a ttributed to the ionization states of the disk and relativistic effects.
Bokaei, B.; Niknam, A. R.; Jafari Milani, M. R.
2013-10-15
The propagation characters of Gaussian laser beam in collisionless plasma are investigated by considering the ponderomotive and relativistic nonlinearities. The second-order differential equation of dimensionless beam width parameter is solved numerically, taking into account the effect of electron temperature. The results show that the ponderomotive force does not facilitate the relativistic self-focusing in all intensity ranges. In fact, there exists a certain intensity value that, if below this value, the ponderomotive nonlinearity can contribute to the relativistic self-focusing, or obstruct it, if above. It is also indicated that there is a temperature interval in which self-focusing can occur, while the beam diverges outside of this region. In addition, the results represent the existence of a “turning point temperature” in the mentioned interval that the self-focusing has the strongest power. The value of the turning point is dependent on laser intensity in which higher intensities result in higher turning point.
Relativistic gravity and parity-violating nonrelativistic effective field theories
NASA Astrophysics Data System (ADS)
Wu, Chaolun; Wu, Shao-Feng
2015-06-01
We show that the relativistic gravity theory can offer a framework to formulate the nonrelativistic effective field theory in a general coordinate invariant way. We focus on the parity violating case in 2 +1 dimensions which is particularly appropriate for the study on quantum Hall effects and chiral superfluids. We discuss how the nonrelativistic spacetime structure emerges from relativistic gravity. We present covariant maps and constraints that relate the field contents in the two theories, which also serve as the holographic dictionary in the context of gauge/gravity duality. A low energy effective action for fractional quantum Hall states is constructed, which captures universal geometric properties and generates nonuniversal corrections systematically. We give another holographic example with dyonic black brane background to calculate thermodynamic and transport properties of strongly coupled nonrelativistic fluids in magnetic field. In particular, by identifying the shift function in the gravity as a minus of guiding center velocity, we obtain the Hall viscosity with its relation to Landau orbital angular momentum density proportional to Wen-Zee shift. Our formalism has a good projection to lowest Landau level.
Elekina, E. N.; Martynenko, A. P.
2010-03-01
On the basis of perturbative QCD and the relativistic quark model we calculate relativistic and bound state corrections in the pair production of S-wave and P-wave charmonium states. Relativistic factors in the production amplitude connected with the relative motion of heavy quarks and the transformation law of the bound state wave function to the reference frame of the moving S- and P-wave mesons are taken into account. For the gluon and quark propagators entering the production vertex function we use a truncated expansion in the ratio of the relative quark momenta to the center-of-mass energy {radical}(s) up to the second order. The relativistic treatment of the wave functions makes all such second order terms convergent, thus allowing the reliable calculation of their contributions to the production cross section. Relativistic corrections to the quark bound state wave functions in the rest frame are considered by means of the QCD generalization of the standard Breit potential. It turns out that the examined effects change essentially the nonrelativistic results of the cross section for the reaction e{sup +}+e{sup -{yields}}J/{Psi}({eta}{sub c})+{chi}{sub cJ}(h{sub c}) at the center-of-mass energy {radical}(s)=10.6 GeV.
Best-fit estimate of relativistic effects in time-delay experiments.
NASA Technical Reports Server (NTRS)
Richard, J.-P.
1972-01-01
Time-delay experiments are analyzed within the frame of a curved space-time. Residuals from Newtonian best fits of relativistic data are used as a measure of the 'relativistic effects.' Radial transponder trajectories are considered. If the motion is towards the sun, the relativistic residuals are of the order of 100 m. If the motion is away from the sun, they are at the 10-km level and the fraction due to the second-order curvature of the metric is at the 1-km level. Those effects are significantly smaller than those calculated from the divergence of the Newtonian and relativistic predictions after exact fit of the initial measurements.
Relativistic Effects and the Chemistry of the Heaviest Main-Group Elements
ERIC Educational Resources Information Center
Thayer, John S.
2005-01-01
The chemical properties of the heaviest main-group elements often show features not found in their lighter counterparts while relativistic effects play an important role in the chemistry of these elements. The unusual properties and their relation to relativistic effects with emphasis on the new research are emphasized.
The effects of radiation drag on radial, relativistic hydromagnetic winds
NASA Technical Reports Server (NTRS)
Li, Zhi-Yun; Begelman, Mitchell C.; Chiueh, Tzihong
1992-01-01
The effects of drag on an idealized relativistic MHD wind of radial geometry are studied. The astrophysical motivation is to understand the effects of radiation drag on the dynamics of a jet or wind passing through the intense radiation field of an accreting compact object. From a critical point analysis, it is found that a slow magnetosonic point can appear in a dragged flow even in the absence of gravitational force, as a result of a balance between the drag force and the combination of thermal pressure and centrifugal forces. As in the undragged case, the Alfven point does not impose any constraints on the flow. Although it is formally possible for a dragged flow to possess more than one fast magnetosonic point, it is shown that this is unlikely in practice. In the limit of a 'cold', centrifugally driven flow, it is shown that the fast magnetosonic point moves to infinite radius, just as in the drag-free case. For a given mass flux, the total energy output carried to infinity, and the final partition between the kinetic energy and the Poynting flux, are the same for the dragged and the drag-free flows. The main effects of radiation drag are to increase the amount of energy and angular momentum extracted from the source and to redistribute the regions where acceleration occurs in the flow. This is accomplished through the storage and release of magnetic energy, as a result of additional winding and compression of the field caused by the action of the drag. For a relativistic wind, the dissipated energy can exceed the final kinetic energy of the flow and may be comparable to the total flow energy (which is dominated by Poynting flux). The energy lost to radiation drag will appear as a Doppler-boosted beam of scattered radiation, which could dominate the background radiation if the flow is well-collimated.
Analogous of Hartman Effect for Relativistic Particles Through "Transparent" Barrier
NASA Astrophysics Data System (ADS)
Germano, Massimo
2015-02-01
The phase time in a nonrelativistic monodimensional tunneling is, for short barrier length, greater than the time it takes for the light in vacuum to travel the same path. Nevertheless, if the length is increased to the limit of "opaque" barrier ( κ L ≫ 1), where κ is the decay constant of the evanescent wave, the phase time becomes independent from the length (Hartman effect), so that apparent superluminal velocities (independently from unresolved questions about their physical meaning) are possible increasing length in this limit. Here is analytically demonstrated that apparent superluminal behavior can be found also in another situation: for highly relativistic particles, in the limit of "transparent barrier" ( κ L ≪ 1), is found that the phase time is always shorter than the correspondent time for light in vacuum, and that apparent superluminal velocities (following the Hartman definition) are always possible independently from the barrier length.
Relativistic optimized effective potential method-application to alkali metals.
Ködderitzsch, D; Ebert, H; Akai, H; Engel, E
2009-02-11
We present a relativistic formulation of the optimized effective potential method (ROEP) and its implementation within the Korringa-Kohn-Rostoker multiple scattering formalism. The scheme is an all-electron approach, treating core and band states formally on the same footing. We use exact exchange (EXX) as an approximation to the exchange correlation functional. Numerical four-component wavefunctions for the description of core and valence electrons and the corresponding ingredients of the ROEP integral equation are employed. The exact exchange expression for the valence states is reformulated in terms of the electronic Green's function that in turn is evaluated by making use of multiple scattering formalism. We present and discuss the application of the formalism to non-magnetic alkali metals. PMID:21715911
NASA Astrophysics Data System (ADS)
Kellö, Vladimir; Sadlej, Andrzej J.
1995-08-01
Electric properties of heteronuclear dimers of the coinage metals are calculated at the level of the CCSD(T) approximation applied to 38 electrons of the valence and next-to-valence atomic shells. The relativistic effects are accounted for by using the scalar approximation to the Pauli hamiltonian. Both the pure relativistic and mixed relativistic-correlation contributions to energies and electric properties are computed. All calculations have been carried out by using the recently developed first-order polarized basis sets of the coinage metal atoms. In the non-relativistic approximation all studied dimers show only a moderate degree of polarity; the non-relativistic CuAg turns out to be the most polar dimer with the Cu(-)Ag(+) polarity. The relativistic effects considerably reduce the negative value of the CuAg dipole moment, change the sign of the CuAu dipole moment, and make the AgAu molecule the most polar species in the series. Simultaneously, the parallel component of the dipole polarizability shows only a small relativistic contraction. The calculated quasirelativistic interaction potentials have a correct behavior in the vicinity of their minima and give the Re and ωe values in complete agreement with experiment. Much less satisfactory are the dissociation energy data which seem to suffer from the single reference configuration approximation.
Feynman's Relativistic Electrodynamics Paradox and the Aharonov-Bohm Effect
NASA Astrophysics Data System (ADS)
Caprez, Adam; Batelaan, Herman
2009-03-01
An analysis is done of a relativistic paradox posed in the Feynman Lectures of Physics involving two interacting charges. The physical system presented is compared with similar systems that also lead to relativistic paradoxes. The momentum conservation problem for these systems is presented. The relation between the presented analysis and the ongoing debates on momentum conservation in the Aharonov-Bohm problem is discussed.
Relativistic viscoelastic fluid mechanics
Fukuma, Masafumi; Sakatani, Yuho
2011-08-15
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Anomalous skin effects in relativistic parallel propagating weakly magnetized electron plasma waves
Abbas, Gohar; Bashir, M. F.; Murtaza, G.
2011-10-15
Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized electron plasma is presented and general expressions for longitudinal and transverse permittivites are derived. It is found that the penetration depth for R- and L-waves increases as we move from non-relativistic to highly relativistic regime. The ambient magnetic field reduces/enhances the skin effects for R-wave/L-wave as the strength of the field is increased. In general, the weak magnetic field effects are pronounced for the weakly relativistic regime as compared with other relativistic cases. The results are also graphically illustrated. On switching off the magnetic field, previous results for field free case are retrieved [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Priniples of Plasma Electrodynamics (Springer-Verlag, Berlin, Heidelberg, 1984), Vol. 9, p. 106].
RELATIVISTIC COLLAPSE AND EXPLOSION OF ROTATING SUPERMASSIVE STARS WITH THERMONUCLEAR EFFECTS
Montero, Pedro J.; Janka, Hans-Thomas; Mueller, Ewald
2012-04-10
We present results of general relativistic simulations of collapsing supermassive stars with and without rotation using the two-dimensional general relativistic numerical code Nada, which solves the Einstein equations written in the BSSN formalism and the general relativistic hydrodynamic equations with high-resolution shock-capturing schemes. These numerical simulations use an equation of state that includes the effects of gas pressure and, in a tabulated form, those associated with radiation and the electron-positron pairs. We also take into account the effect of thermonuclear energy released by hydrogen and helium burning. We find that objects with a mass of Almost-Equal-To 5 Multiplication-Sign 10{sup 5} M{sub Sun} and an initial metallicity greater than Z{sub CNO} Almost-Equal-To 0.007 do explode if non-rotating, while the threshold metallicity for an explosion is reduced to Z{sub CNO} Almost-Equal-To 0.001 for objects uniformly rotating. The critical initial metallicity for a thermonuclear explosion increases for stars with a mass Almost-Equal-To 10{sup 6} M{sub Sun }. For those stars that do not explode, we follow the evolution beyond the phase of black hole (BH) formation. We compute the neutrino energy loss rates due to several processes that may be relevant during the gravitational collapse of these objects. The peak luminosities of neutrinos and antineutrinos of all flavors for models collapsing to a BH are L{sub {nu}} {approx} 10{sup 55} erg s{sup -1}. The total radiated energy in neutrinos varies between E{sub {nu}} {approx} 10{sup 56} erg for models collapsing to a BH and E{sub {nu}} {approx} 10{sup 45}-10{sup 46} erg for models exploding.
Relativistic Collapse and Explosion of Rotating Supermassive Stars with Thermonuclear Effects
NASA Astrophysics Data System (ADS)
Montero, Pedro J.; Janka, Hans-Thomas; Müller, Ewald
2012-04-01
We present results of general relativistic simulations of collapsing supermassive stars with and without rotation using the two-dimensional general relativistic numerical code Nada, which solves the Einstein equations written in the BSSN formalism and the general relativistic hydrodynamic equations with high-resolution shock-capturing schemes. These numerical simulations use an equation of state that includes the effects of gas pressure and, in a tabulated form, those associated with radiation and the electron-positron pairs. We also take into account the effect of thermonuclear energy released by hydrogen and helium burning. We find that objects with a mass of ≈5 × 105 M ⊙ and an initial metallicity greater than Z CNO ≈ 0.007 do explode if non-rotating, while the threshold metallicity for an explosion is reduced to Z CNO ≈ 0.001 for objects uniformly rotating. The critical initial metallicity for a thermonuclear explosion increases for stars with a mass ≈106 M ⊙. For those stars that do not explode, we follow the evolution beyond the phase of black hole (BH) formation. We compute the neutrino energy loss rates due to several processes that may be relevant during the gravitational collapse of these objects. The peak luminosities of neutrinos and antineutrinos of all flavors for models collapsing to a BH are L ν ~ 1055 erg s-1. The total radiated energy in neutrinos varies between E ν ~ 1056 erg for models collapsing to a BH and E ν ~ 1045-1046 erg for models exploding.
Spinodal instabilities and the distillation effect in relativistic hadronic models
Avancini, S. S.; Menezes, D. P.; Brito, L.; Provide circumflex ncia, C.; Chomaz, Ph.
2006-08-15
Liquid-gas phase transitions in asymmetric nuclear matter give rise to a distillation effect that corresponds to the formation of droplets of high-density symmetric matter in a background of a neutron gas possibly with a very small fraction of protons. In the present work we test the model dependence of this effect. We study the spinodal instabilities of asymmetric nuclear matter within six different mean-field relativistic models with both constant and density-dependent coupling parameters. We also consider the effects of introducing the {delta} meson and the nonlinear {omega}-{rho} coupling. It is shown that the distillation effect within density-dependent models is not so efficient and is comparable to results obtained for nonrelativistic models. Thermodynamical instabilities of nuclear matter neutralized by electrons as found in stellar matter are also investigated. The high Fermi energy of electrons completely erases the instability of density-dependent models. The other models still show a small region of instability but the distillation effect completely disappears because the electron presence freezes the proton fluctuations.
Effects of δ mesons in relativistic mean field theory
NASA Astrophysics Data System (ADS)
Singh, Shailesh K.; Biswal, S. K.; Bhuyan, M.; Patra, S. K.
2014-04-01
The effect of δ- and ω-ρ-meson cross couplings on asymmetry nuclear systems are analyzed in the framework of an effective field theory motivated relativistic mean field formalism. The calculations are done on top of the G2 parameter set, where these contributions are absent. To show the effect of δ meson on the nuclear system, we split the isospin coupling into two parts: (i) gρ due to ρ meson and (ii) gδ for δ meson. Thus, our investigation is based on varying the coupling strengths of the δ and ρ mesons to reproduce the binding energies of the nuclei Ca48 and Pb208. We calculate the root mean square radius, binding energy, single particle energy, density, and spin-orbit interaction potential for some selected nuclei and evaluate the Lsym and Esym coefficients for nuclear matter as function of δ- and ω-ρ-meson coupling strengths. As expected, the influence of these effects are negligible for the symmetric nuclear system, but substantial for the contribution with large isospin asymmetry.
Relativistic effects on the nuclear magnetic shielding tensor
NASA Astrophysics Data System (ADS)
Melo, J. I.; Ruiz de Azua, M. C.; Giribet, C. G.; Aucar, G. A.; Romero, R. H.
2003-01-01
A new approach for calculating relativistic corrections to the nuclear magnetic shieldings is presented. Starting from a full relativistic second order perturbation theory expression a two-component formalism is constructed by transforming matrix elements using the elimination of small component scheme and separating out the contributions from the no-virtual pair and the virtual pair part of the second order corrections to the energy. In this way we avoid a strong simplification used previously in the literature. We arrive at final expressions for the relativistic corrections which are equivalent to those of Fukui et al. [J. Chem Phys. 105, 3175 (1996)] and at some other additional terms correcting both the paramagnetic and the diamagnetic part of the nuclear magnetic shielding. Results for some relativistic corrections to the shieldings of the heavy and light nuclei in HX and CH3X (X=Br,I) at both random phase and second order polarization propagator approach levels are given.
Effects of radiation reaction in relativistic laser acceleration
Hadad, Y.; Labun, L.; Rafelski, J.; Elkina, N.; Klier, C.; Ruhl, H.
2010-11-01
The goal of this paper is twofold: to explore the response of classical charges to electromagnetic force at the level of unity in natural units and to establish a criterion that determines physical parameters for which the related radiation-reaction effects are detectable. In pursuit of this goal, the Landau-Lifshitz equation is solved analytically for an arbitrary (transverse) electromagnetic pulse. A comparative study of the radiation emission of an electron in a linearly polarized pulse for the Landau-Lifshitz equation and for the Lorentz force equation reveals the radiation-reaction-dominated regime, in which radiation-reaction effects overcome the influence of the external fields. The case of a relativistic electron that is slowed down by a counterpropagating electromagnetic wave is studied in detail. We further show that when the electron experiences acceleration of order unity, the dynamics of the Lorentz force equation, the Landau-Lifshitz equation and the Lorentz-Abraham-Dirac equation all result in different radiation emission that could be distinguished in experiment. Finally, our analytic and numerical results are compared with those appearing in the literature.
Relativistic Effects in the Photoionization-Excitation of Neon
NASA Astrophysics Data System (ADS)
Gorczyca, T. W.; Felfli, Z.
1998-05-01
In a purely non-relativistic theoretical treatment of the neon 2p^43s(^2P) satellite, the angular distribution parameter and the ratio of populations of the ^2P_3/2 and ^2P_1/2 ionic fine structure levels are both independent of photon energy. Recent synchrotron measurements(A. A. Wills, N. Berrah, T. W. Gorczyca, B. Langer, Z. Felfli, M. Alsheri, O. Nayandin, and J. D. Bozek, unpublished) have observed marked deviation from this predicted behavior, however, indicating that spin-orbit effects are important. In order to study spin-orbit effects in this region of complex doubly-excited resonances, we have performed R-matrix calculations to determine MQDT scattering and dipole matrices. Important computational aspects are 1) an extensive configuration interaction (CI) for target and scattering wavefunctions, 2) a recoupling transformation from LS-coupled to JK-coupled matrices, 3) a second transformation using term coupling coefficients of the ionic targets, and 4) the MQDT reduction to physical scattering matrices using experimental fine structure target energies. The resultant differential cross sections, resolved into photoelectron angle and final ionic fine structure level, show many interesting deviations from the LS-predicted behavior, and are compared to the recent experimental results.^1
Relativistic effects in the photoionization of hydrogen-like ions with screened Coulomb interaction
Xie, L. Y.; Wang, J. G.; Janev, R. K.
2014-06-15
The relativistic effects in the photoionization of hydrogen-like ion with screened Coulomb interaction of Yukawa type are studied for a broad range of screening lengths and photoelectron energies. The bound and continuum wave functions have been determined by solving the Dirac equation. The study is focused on the relativistic effects manifested in the characteristic features of photoionization cross section for electric dipole nl→ε,l±1 transitions: shape resonances, Cooper minima and cross section enhancements due to near-zero-energy states. It is shown that the main source of relativistic effects in these cross section features is the fine-structure splitting of bound state energy levels. The relativistic effects are studied in the photoionization of Fe{sup 25+} ion, as an example.
Doppler factors in satellite-to-satellite tracking. [with relativistic effects
NASA Technical Reports Server (NTRS)
Marini, J. W.
1974-01-01
The Doppler factors occurring in range rate satellite-to-satellite tracking measurements are derived with special relativistic effects included. The error resulting from the use of simplified expressions for these factors is discussed.
Observation of relativistic effects in collective Thomson scattering
Ross, J S; Glenzer, S H; Palastro, J P; Pollock, B B; Price, D; Divol, L; Tynan, G R; Froula, D H
2009-10-08
We observe relativistic modifications to the Thomson scattering spectrum in a traditionally classical regime: v{sub osc}/c = eE{sub 0}/cm{omega}{sub 0} << 1 and T{sub e} < 1 keV. The modifications result from scattering off electron-plasma fluctuations with relativistic phase velocities. Normalized phase velocities v/c between 0.03 and 0.12 have been achieved in a N{sub 2} gas-jet plasma by varying the plasma density from 3 x 10{sup 18} cm{sup -3} to 7 x 10{sup 19} cm{sup -3} and electron temperature between 85 eV and 700 eV. For these conditions, the complete temporally resolved Thomson scattering spectrum including the electron and ion features has been measured. A fully relativistic treatment of the Thomson scattering form factor has been developed and shows excellent agreement with the experimental data.
Poszwa, A.; Bahar, M. K.
2015-01-15
The influence of relativistic and plasma screening effects on energies of hydrogen-like atoms embedded in plasmas has been studied. The Dirac equation with a more general exponential cosine screened potential has been solved numerically and perturbatively, by employing the direct perturbation theory. Properties of spectra corresponding to bound states and to different sets of the potential parameters have been studied both in nonrelativistic and relativistic approximations. Binding energies, fine-structure splittings, and relativistic energy shifts have been determined as functions of parameters of the potential. The results have been compared with the ones known from the literature.
Zhao, Yao; Zheng, Jun; Chen, Min; Yu, Lu-Le; Weng, Su-Ming; Ren, Chuang; Liu, Chuan-Sheng; Sheng, Zheng-Ming E-mail: zhengming.sheng@strath.ac.uk
2014-11-15
Effects of relativistic electron temperature on stimulated Raman scattering and stimulated Brillouin scattering instabilities for high intensity lasers propagating in underdense plasma are studied theoretically and numerically. The dispersion relations for these instabilities are derived from the relativistic fluid equation. For a wide range of laser intensity and electron temperature, it is found that the maximum growth rate and the instability region in k-space can be reduced at relativistic electron temperature. Particle-in-cell simulations are carried out, which confirm the theoretical analysis.
Spin dynamics in relativistic light-matter interaction
NASA Astrophysics Data System (ADS)
Bauke, Heiko; Ahrens, Sven; Keitel, Christoph H.; Grobe, Rainer
2015-05-01
Various spin effects are expected to become observable in light-matter interaction at relativistic intensities. Relativistic quantum mechanics equipped with a suitable relativistic spin operator forms the theoretical foundation for describing these effects. Various proposals for relativistic spin operators have been offered by different authors, which are presented in a unified way. As a result of the operators' mathematical properties only the Foldy-Wouthuysen operator and the Pryce operator qualify as possible proper relativistic spin operators. The ground states of highly charged hydrogen-like ions can be utilized to identify a legitimate relativistic spin operator experimentally. Subsequently, the Foldy-Wouthuysen spin operator is employed to study electron-spin precession in high-intensity standing light waves with elliptical polarization. For a correct theoretical description of the predicted electron-spin precession relativistic effects due to the spin angular momentum of the electromagnetic wave has to be taken into account even in the limit of low intensities.
Relativistic calculations of the nuclear recoil effect in highly charged Li-like ions
NASA Astrophysics Data System (ADS)
Zubova, N. A.; Shabaev, V. M.; Tupitsyn, I. I.; Plunien, G.
2013-09-01
Relativistic theory of the nuclear recoil effect in highly charged Li-like ions is considered within the Breit approximation. The normal mass shift (NMS) and the relativistic NMS (RNMS) are calculated by perturbation theory to zeroth and first orders in the parameter 1/Z. The calculations are performed using the dual kinetic balance method with the basis functions constructed from B-splines. The results of the calculations are compared with the theoretical values obtained by other methods.
Niknam, A. R.; Hashemzadeh, M.; Shokri, B.
2009-03-15
The effect of the weakly relativistic ponderomotive force in the interaction of an intense laser pulse with an underdense plasma is studied. This force modifies the electron density distribution. Furthermore, the existence of intense laser pulses in plasma causes the electron relativistic mass to appear and, consequently, the plasma frequency decreases. It is clear that the electron temperature also affects the dielectric permittivity of plasma. By considering the weakly relativistic and ponderomotive effects, the nonlinear dielectric permittivity of plasma is obtained. Taking into account the Maxwell equations and the nonlinear dielectric permittivity, the electric and magnetic field profiles in plasma are investigated. It is shown that the electromagnetic field profiles deviate from sinusoidal structure. Also, the steepening of the electron density profile decreases by increasing the electron temperature and decreasing the laser pulse intensity. The wavelength of oscillations decreases by increasing the energy flux. Finally, it is found that the electric and magnetic field profiles are lengthened by increasing the electron temperature.
Ab initio investigation of light-induced relativistic spin-flip effects in magneto-optics
NASA Astrophysics Data System (ADS)
Mondal, Ritwik; Berritta, Marco; Carva, Karel; Oppeneer, Peter M.
2015-05-01
Excitation of a metallic ferromagnet such as Ni with an intensive femtosecond laser pulse causes an ultrafast demagnetization within approximately 300 fs. It was proposed that the ultrafast demagnetization measured in femtosecond magneto-optical experiments could be due to relativistic light-induced processes. We perform an ab initio investigation of the influence of relativistic effects on the magneto-optical response of Ni. To this end, first, we develop a response theory formulation of the additional appearing ultrarelativistic terms in the Foldy-Wouthuysen transformed Dirac Hamiltonian due to the electromagnetic field, and second, we compute the influence of relativistic light-induced spin-flip transitions on the magneto-optics. Our ab initio calculations of relativistic spin-flip optical excitations predict that these can give only a very small contribution (≤0.1 %) to the laser-induced magnetization change in Ni.
Relativistic effects on the thermal expansion of the actinide elements
Soederlind, P.; Nordstroem, L.; Lou Yongming; Johansson, B. )
1990-09-01
The room-temperature linear thermal-expansion coefficient is calculated for the light actinides thorium, protactinium, uranium, neptunium, and plutonium for the fcc crystal structure. The relativistic spin-orbit interaction is included in these calculations. We show that the spin-orbit splitting of the 5{ital f} band gives rise to a considerable increase of the thermal expansion and to a large extent explains the observed anomalously large thermal expansion for the neptunium and plutonium metals.
Geometric relativistic phase from Lorentz symmetry breaking effects in the cosmic string spacetime
NASA Astrophysics Data System (ADS)
Belich, H.; Bakke, K.
2016-04-01
In this paper, we have investigated the arising of geometric quantum phases in a relativistic quantum dynamics of a Dirac neutral particle from the spontaneous Lorentz symmetry violation effects in the cosmic string spacetime. We started by the Dirac equation in an effective metric, and we have observed a relativistic geometric phase which stems from the topology of the cosmic string spacetime and an intrinsic Lorentz symmetry breaking effects. It is shown that both Lorentz symmetry breaking effects and the topology of the defect yields a phase shift in the wave function of the nonrelativistic spin-1/2 particle.
Bakke, K.; Belich, H.
2013-06-15
In this work, we discuss the relativistic Landau–He–McKellar–Wilkens quantization and relativistic bound states solutions for a Dirac neutral particle under the influence of a Coulomb-like potential induced by the Lorentz symmetry breaking effects. We present new possible scenarios of studying Lorentz symmetry breaking effects by fixing the space-like vector field background in special configurations. It is worth mentioning that the criterion for studying the violation of Lorentz symmetry is preserving the gauge symmetry. -- Highlights: •Two new possible scenarios of studying Lorentz symmetry breaking effects. •Coulomb-like potential induced by the Lorentz symmetry breaking effects. •Relativistic Landau–He–McKellar–Wilkens quantization. •Exact solutions of the Dirac equation.
ERIC Educational Resources Information Center
The Newsletter of the Comprehensive Center-Region VI, 1999
1999-01-01
Controversy surrounding the accountability movement is related to how the movement began in response to dissatisfaction with public schools. Opponents see it as one-sided, somewhat mean-spirited, and a threat to the professional status of teachers. Supporters argue that all other spheres of the workplace have accountability systems and that the…
ERIC Educational Resources Information Center
Lashway, Larry
1999-01-01
This issue reviews publications that provide a starting point for principals looking for a way through the accountability maze. Each publication views accountability differently, but collectively these readings argue that even in an era of state-mandated assessment, principals can pursue proactive strategies that serve students' needs. James A.…
Small amplitude solitons in a warm plasma with smaller and higher order relativistic effects
Kalita, B. C.; Das, R.
2007-07-15
Solitons have been investigated in a warm plasma through the Korteweg-de Vries (KdV) equation, considering a smaller relativistic effect for {gamma}{approx_equal}O(v{sup 2}/c{sup 2}) and {gamma}{sub e}{approx_equal}O(u{sup 2}/c{sup 2}) and higher relativistic effects for {gamma}{approx_equal}O(v{sup 4}/c{sup 4}) and {gamma}{sub e}{approx_equal}O(u{sup 4/}c{sup 4}). Compressive fast ion-acoustic solitons are observed to exist in the entire range (u{sub 0}-v{sub 0}) subject to a suitable mathematical condition satisfied by the initial streaming velocities u{sub 0},v{sub 0} of the electrons and the ions, respectively, electron to ion mass ratio Q(=m{sub e}/m{sub i}) and ion to electron temperature ratio {sigma}(=T{sub i}/T{sub e}). Further, rarefactive solitons of pretty small amplitudes are observed in the small upper range of |u{sub 0}-v{sub 0}| for higher order relativistic effect which are found to change parabolically. It is essentially important to report in our model of plasma, that the higher order relativistic effect slows down the soliton speed to V{<=}0.10 for all temperature ratios {sigma} for small amplitude waves. On the other hand, the smaller order relativistic effect permits the soliton to exist even at a relatively much higher speed V<0.30. Solitons of high (negligible) amplitudes are found to generate at the smaller (greater) difference of initial streamings (u{sub 0}-v{sub 0}) corresponding to both the relativistic effects.
Electron Correlation in 4-Component Relativistic Calculations
NASA Technical Reports Server (NTRS)
Visscher, Luuk; Arnold, James O. (Technical Monitor)
1994-01-01
The full 4-component Dirac-Coulomb equation can nowadays be used in molecular calculations, The first step in solving this relativistic many-electron equation usually consists of solving the closed or open-shell Diarc-Fock equations. Like in non-relativistic calculations the outcome does not account for the effects of electron correlation. This can in principle be remedied by developing relativistic variants of electron correlation methods like Configuration Interaction or Coupled Cluster. In this talk the differences and similarities of such relativistic approaches as compared to non-relativistic methods will be reviewed. Results of Configuration Interaction calculations on the PtH molecule and on the MeF(sub 6, sup 2-) (Me= Co, Rh, Ir) complexes will be presented to give an impression of the kind of results that currently can be obtained.
Effect of the plasma-generated magnetic field on relativistic electron transport.
Nicolaï, Ph; Feugeas, J-L; Regan, C; Olazabal-Loumé, M; Breil, J; Dubroca, B; Morreeuw, J-P; Tikhonchuk, V
2011-07-01
In the fast-ignition scheme, relativistic electrons transport energy from the laser deposition zone to the dense part of the target where the fusion reactions can be ignited. The magnetic fields and electron collisions play an important role in the collimation or defocusing of this electron beam. Detailed description of these effects requires large-scale kinetic calculations and is limited to short time intervals. In this paper, a reduced kinetic model of fast electron transport coupled to the radiation hydrodynamic code is presented. It opens the possibility to carry on hybrid simulations in a time scale of tens of picoseconds or more. It is shown with this code that plasma-generated magnetic fields induced by noncollinear temperature and density gradients may strongly modify electron transport in a time scale of a few picoseconds. These fields tend to defocus the electron beam, reducing the coupling efficiency to the target. This effect, that was not seen before in shorter time simulations, has to be accounted for in any ignition design using electrons as a driver. PMID:21867317
The effect of density gradient on the growth rate of relativistic Weibel instability
Mahdavi, M.; Khodadadi Azadboni, F.
2014-02-15
In this paper, the effect of density gradient on the Weibel instability growth rate is investigated. The density perturbations in the near corona fuel, where temperature anisotropy, η, is larger than the critical temperature anisotropy, η{sub c}, (η > η{sub c}), enhances the growth rate of Weibel instability due to the sidebands coupled with the electron oscillatory velocity. But for η < η{sub c}, the thermal spread of the energetic electrons reduces the growth rate. Also, the growth rate can be reduced if the relativistic parameter (Lorentz factor) is sufficiently large, γ > 2. The analysis shows that relativistic effects and density gradient tend to stabilize the Weibel instability. The growth rate can be reduced by 88% by reducing η by a factor of 100 and increasing relativistic parameter by a factor of 3.
NASA Astrophysics Data System (ADS)
Prasannaa, V. S.; Sreerekha, S.; Abe, M.; Bannur, V. M.; Das, B. P.
2016-04-01
The interplay of the relativistic and correlation effects in the permanent electric dipole moments of the X 2Σ+ electronic ground states of the alkaline-earth-metal monofluorides (BeF, MgF, CaF, SrF, and BaF) has been studied using a relativistic coupled cluster method. The calculations were carried out using double, triple, and quadruple zeta basis sets, and with no core orbitals frozen. The results are compared with those of other calculations available in the literature and with experiments. The correlation trends in the permanent electric dipole moments of these molecules are discussed in detail. This information will be useful in throwing light on the interplay between relativistic and correlation effects of other properties that are relevant to fundamental physics.
Sen, Sonu Dubey, A.; Varshney, Meenu Asthana; Varshney, Dinesh
2014-04-24
In the present paper we make an analytical investigation to study transport properties with relativistic ponderomotive effect in two-electron temperature plasma. Using fluid model the two-electron temperature are introduced through relativistic ponderomotive force for the transportation of two species of electrons. Applying WKB and paraxial ray approximation the nonlinear dielectric constant and self-focusing equation is evaluated and analyzed with experimental relevance. Numerical calculations are made for different concentration of electron density (10{sup 19}−10{sup 21} per cm{sup 3}) at arbitrary values of laser intensity in the range 10{sup 18}−10{sup 21} W/cm{sup 2}. For a minimum radius depending on the initial conditions it is oscillating between a minimum and maximum value. The hot electrons leading to the increase of the on-axis transportation and favorable effect on relativistic self-focusing.
Atomic electron energies including relativistic effects and quantum electrodynamic corrections
NASA Technical Reports Server (NTRS)
Aoyagi, M.; Chen, M. H.; Crasemann, B.; Huang, K. N.; Mark, H.
1977-01-01
Atomic electron energies have been calculated relativistically. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all orbitals in all atoms with 2 less than or equal to Z less than or equal to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. These results will serve for detailed comparison of calculations based on other approaches. The magnitude of quantum electrodynamic corrections is exhibited quantitatively for each state.
Relativistic correlation effects on the x-ray spectra of Li-like ions
NASA Astrophysics Data System (ADS)
Natarajan, L.
2016-03-01
The wavelengths and rates of electric dipole transitions between states with n =2 and n =1 of doubly excited Li-like ions have been studied for some selected ions in the range 13 ≤Z ≤54 using fully relativistic multiconfiguration Dirac-Fock wave functions in the active space approximation with the inclusion of finite nuclear size, Breit interaction, self-energy, and vacuum polarization. A detailed discussion on the effects of intercomplex correlation around Z =26 and intracomplex correlation around Z =37 leading to irregularities and sharp discontinuities in the x-ray rates noticed for a few transitions has been provided. An unusually large contribution of Breit interaction has been found for intercomplex correlation in certain cases. The present results are compared with other available experimental and theoretical data. The errors associated with the transitions are highlighted for some experimentally available lines taking into account the uncertainties on the fine-structure energy levels and also on the line strengths.
Relativistic and Correlation Effects in CuH, AgH and AuH: Comparison of Various Relativistic Methods
NASA Technical Reports Server (NTRS)
Collins, Charlene L.; Dyall, Kenneth G.; Schaefer, Henry F., III
1994-01-01
The effects of relativity on the bond lengths, dissociation energies, and harmonic vibrational frequencies of the 1Epsilon(+) electronic ground states of the group IB hydrides CuH, AgH and AuH have been evaluated with a variety of ab initio methods. These properties were investigated with moderately-sized basis sets at the self-consistent field Hartree Fock (SCF HF) level and with second-order Moller-Plesset (MP2) perturbation theory for electron correlation. Comparisons were made between all-electron results using the nonrelativistic Hamiltonian, perturbation theory (PT) at first-order with only the one-electron non-fine structure terms of the Breit-Pauli Hamiltonian, the spin-free Douglas-Kroll (DK) transformed Dirac Hamiltonian and the untransformed Dirac Hamiltonian, and results using two sets of relativistic effective core potentials (RECPs). The expected trends of bond length decrease, dissociation energy increase and harmonic frequency increase with both relativity and correlation are found. Both sets of RECPs are shown to give good results, if accompanied by a reasonable basis set. The DK method is demonstrated to be an inexpensive, reliable approximation to the DHF method.
Dirac Equation and Quantum Relativistic Effects in a Single Trapped Ion
Lamata, L.; Leon, J.; Schaetz, T.; Solano, E.
2007-06-22
We present a method of simulating the Dirac equation in 3+1 dimensions for a free spin-1/2 particle in a single trapped ion. The Dirac bispinor is represented by four ionic internal states, and position and momentum of the Dirac particle are associated with the respective ionic variables. We show also how to simulate the simplified 1+1 case, requiring the manipulation of only two internal levels and one motional degree of freedom. Moreover, we study relevant quantum-relativistic effects, like the Zitterbewegung and Klein's paradox, the transition from massless to massive fermions, and the relativistic and nonrelativistic limits, via the tuning of controllable experimental parameters.
Relativistic effects of the rotation of the earth on remote clock synchronization
NASA Technical Reports Server (NTRS)
Reinhardt, V.
1974-01-01
A treatment is given of relativistic clock synchronization effects due to the rotation of the earth. Unlike other approaches, the point of view of an earth fixed coordinate system is used which offers insight to many problems. An attempt is made to give the reader an intuitive grasp of the subject as well as to provide formulae for his use. Specific applications to global timekeeping, navigation, VLBI, relativistic clock experiments, and satellite clock synchronization are discussed. The question of whether atomic clocks are ideal clocks is also treated.
Influence of relativistic effects on satellite-based clock synchronization
NASA Astrophysics Data System (ADS)
Wang, Jieci; Tian, Zehua; Jing, Jiliang; Fan, Heng
2016-03-01
Clock synchronization between the ground and satellites is a fundamental issue in future quantum telecommunication, navigation, and global positioning systems. Here, we propose a scheme of near-Earth orbit satellite-based quantum clock synchronization with atmospheric dispersion cancellation by taking into account the spacetime background of the Earth. Two frequency entangled pulses are employed to synchronize two clocks, one at a ground station and the other at a satellite. The time discrepancy of the two clocks is introduced into the pulses by moving mirrors and is extracted by measuring the coincidence rate of the pulses in the interferometer. We find that the pulses are distorted due to effects of gravity when they propagate between the Earth and the satellite, resulting in remarkably affected coincidence rates. We also find that the precision of the clock synchronization is sensitive to the source parameters and the altitude of the satellite. The scheme provides a solution for satellite-based quantum clock synchronization with high precision, which can be realized, in principle, with current technology.
Search for general relativistic effects in table-top displacement metrology
NASA Technical Reports Server (NTRS)
Halverson, Peter G.; Diaz, Rosemary T.; Macdonald, Daniel R.
2004-01-01
As displacement metrology accuracy improves, general relativistic effects will become noticeable. Metrology gauges developed for the Space Interferometry Mission, were used to search for locally anisotropic space-time, with a null result at the 10 to the negative 10th power level.
Search for general relativistic effects in table-top displacement metrology
NASA Technical Reports Server (NTRS)
Halverson, Peter G.; Macdonald, Daniel R.; Diaz, Rosemary T.
2004-01-01
As displacement metrology accuracy improves, general relativistic effects will become noticeable. Metrology gauges developed for the Space Interferometry Mission were used to search for locally anisotropic space-time, with a null result at the 10 to the negative tenth power level.
Acceleration of positrons by a relativistic electron beam in the presence of quantum effects
Niknam, A. R.; Aki, H.; Khorashadizadeh, S. M.
2013-09-15
Using the quantum magnetohydrodynamic model and obtaining the dispersion relation of the Cherenkov and cyclotron waves, the acceleration of positrons by a relativistic electron beam is investigated. The Cherenkov and cyclotron acceleration mechanisms of positrons are compared together. It is shown that growth rate and, therefore, the acceleration of positrons can be increased in the presence of quantum effects.
NASA Technical Reports Server (NTRS)
Wu, Jianshi; Derrickson, J. H.; Parnell, T. A.; Strayer, M. R.
1999-01-01
We study the screening effects of the atomic electrons in the electromagnetic production of electron-positron pairs in relativistic nucleus-atom collisions for fixed target experiments. Our results are contrasted with those obtained in bare collisions, with particular attention given to its dependence on the beam energy and the target atom.
NASA Technical Reports Server (NTRS)
Huo, Winifred M.; Kim, Yong-Ki
1999-01-01
Based on the Binary-Encounter-Bethe (BEB) model, the advantage of using relativistic effective core potentials (RECP) in the calculation of total ionization cross sections of heavy atoms or molecules containing heavy atoms is discussed. Numerical examples for Ar, Kr, Xe, and WF6 are presented.
Relativistic effects on giant resonances in electron-impact double ionization
Pindzola, M.S.
1987-06-01
The electron-impact double-ionization cross section for Fr/sup +/ is calculated in the distorted-wave Born approximation. A giant resonance in the 5d subshell ionization-autoionization contribution to the cross section is found to be quite sensitive to changes in the double-well potential caused by relativistic effects on bound-state wave functions.
Sohbatzadeh, F.; Akou, H.
2013-04-15
The excitation of wake field plasma waves by a short laser pulse propagating through a parabolic plasma channel is studied. The laser pulse is assumed to be initially chirped. In this regard, the effects of initial and induced chirp on the plasma wake field as well as the laser pulse parameters are investigated. The group velocity dispersion and nonlinear relativistic effects were taken into account to evaluate the excited wake field in two dimension using source dependent expansion method. Positive, negative, and un-chirped laser pulses were employed in numerical code to evaluate the effectiveness of the initial chirp on 2-D wake field excitation. Numerical results showed that for laser irradiances exceeding 10{sup 18}W/cm{sup 2}, an intense laser pulse with initial positive chirp generates larger wake field compared to negatively and un-chirped pulses.
NASA Astrophysics Data System (ADS)
Sohbatzadeh, F.; Akou, H.
2013-04-01
The excitation of wake field plasma waves by a short laser pulse propagating through a parabolic plasma channel is studied. The laser pulse is assumed to be initially chirped. In this regard, the effects of initial and induced chirp on the plasma wake field as well as the laser pulse parameters are investigated. The group velocity dispersion and nonlinear relativistic effects were taken into account to evaluate the excited wake field in two dimension using source dependent expansion method. Positive, negative, and un-chirped laser pulses were employed in numerical code to evaluate the effectiveness of the initial chirp on 2-D wake field excitation. Numerical results showed that for laser irradiances exceeding 1018W/cm2, an intense laser pulse with initial positive chirp generates larger wake field compared to negatively and un-chirped pulses.
The Effect of Pre-formed Plasmas on Relativistic Electron Acceleration
NASA Astrophysics Data System (ADS)
Park, Jaebum; Divol, Laurent; Chen, Hui; Nagel, Sabrina; Williams, G. Jackson; Kerr, Shaun
2014-10-01
Pre-formed plasmas effects have been extensively studied and are known to affect relativistic electrons production via laser plasma interactions. However, there are still many unknowns, such as laser energy absorption vs. scale-length and material dependence. We have investigated the pre-formed plasmas effects on relativistic electrons by simultaneously measuring the plasma density with a 2w optical interferometer and relativistic electron energy distributions on the LLNL Titan laser. The pre-formed plasmas were produced on Parylene-N and Ti targets by a separate laser and/or the ASE of the short pulse (SP) laser with upper 1019 W/cm2 at 1w. A 3-D wedge geometry HYDRA simulation is used to benchmark sub-critical density and infer scale-length at the critical density. Electron energy ratios of along the SP beam to the target back normal show stronger pre-formed plasmas effects on creation of relativistic electrons from Parylene-N than Ti. This work was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344 and funded by LDRD (#12-ERD-062).
On the Curvature Effect of a Relativistic Spherical Shell
NASA Astrophysics Data System (ADS)
Uhm, Z. Lucas; Zhang, Bing
2015-07-01
We consider a relativistic spherical shell and calculate its spectral flux as received by a distant observer. Using two different methods, we derive a simple analytical expression of the observed spectral flux and show that the well-known relation \\hat{α }=2+\\hat{β } (between temporal index \\hat{α } and spectral index \\hat{β }) of the high-latitude emission is naturally achieved in our derivation but holds only when the shell moves with a constant Lorentz factor Γ. Presenting numerical models in which the shell is undergoing acceleration or deceleration, we show that the simple \\hat{α }=2+\\hat{β } relation does indeed deviate as long as Γ is not constant. For the models under acceleration, we find that the light curves produced purely by the high-latitude emission initially exhibit much steeper decay than in the constant Γ case and gradually resume the \\hat{α }=2+\\hat{β } relation in about one and a half orders of magnitude in observer time. For the models under deceleration, the trend is opposite. The light curves made purely by the high-latitude emission initially exhibit a shallower decay than in the constant Γ case and gradually resume the relation \\hat{α }=2+\\hat{β } in a similar order of magnitude in observer time. We also show that how fast the Lorentz factor Γ of the shell increases or decreases is the main ingredient determining the initial steepness or shallowness of the light curves.
Cost-Effectiveness in Individual Development Accounts
ERIC Educational Resources Information Center
Schreiner, Mark; Ng, Guat Tin; Sherraden, Michael
2006-01-01
Because resources are limited, the benefits and costs of social-work interventions--like all interventions--must be compared with the benefits and costs of alternatives. Evidence-based practice should ask, What works? How well does it work? And what does it cost? This article analyzes the provision of Individual Development Accounts (IDAs) with a…
Designing More Effective Accountability Report Cards
ERIC Educational Resources Information Center
Sabbah, Faris M.
2011-01-01
The purpose of this study was to identify and design standards and procedures for creating easily interpreted accountability reports cards, consistent with the requirements spelled out in the No Child Left Behind Act of 2001 (NCLB). The use of public report cards was first raised during the debate that took place immediately prior to the passage…
de Jong, G Theodoor; Kovacs, Attila; Bickelhaupt, F Matthias
2006-06-29
We have theoretically studied the oxidative addition of HX and X(2) to palladium for X = F, Cl, Br, I and At, using both nonrelativistic and ZORA-relativistic density functional theory at BLYP/QZ4P. The purpose is 3-fold: (i) to obtain a set of consistent potential energy surfaces (PESs) to infer accurate trends in reactivity for simple, archetypal oxidative addition reactions; (ii) to assess how relativistic effects modify these trends along X = F, Cl, Br, I and At; and (iii) to rationalize the trends in reactivity in terms of the reactants' molecular-orbital (MO) electronic structure and the H-X and X-X bond strengths. For the latter, we provide full Dirac-Coulomb CCSD(T) benchmarks. All oxidative additions to Pd are exothermic and have a negative overall barrier, except that of HF which is approximately thermoneutral and has a positive overall barrier. The activation barriers of the HX oxidative additions decrease systematically as X descends in group 17 of the periodic table; those of X(2) first increase, from F to Cl, but then also decrease further down group 17. On the other hand, HX and X(2) show clearly opposite trends regarding the heat of reaction: that of HX becomes more exothermic and that of X(2) less exothermic as X descends in group 17. Relativistic effects can be as large as 15-20 kcal/mol but they do not change the qualitative trends. Interestingly, the influence of relativistic effects on activation barriers and heats of reaction decreases for the heavier halogens due to counteracting relativistic effects in palladium and the halogens. PMID:16789784
NASA Astrophysics Data System (ADS)
Lazur, V. Yu.; Pavlyk, O. F.; Reity, A. K.
2010-10-01
We solve the problem of interaction two quasimolecular electrons located at an arbitrary separation near different atoms (nuclei). We consider third-order effects in quantum electrodynamics, which include the virtual photon exchange between electrons with emission (absorption) of a real photon. We obtain the general expression for matrix elements of the operator of the effective interaction energy of two quasimolecular electrons with the external radiation field, which allows calculating probabilities of inelastic processes with rearrangement at slow collisions of multicharge ions with relativistic atoms. We demonstrate that consistently taking the natural condition of the interaction symmetry with respect to the two electrons into account results in the appearance of additional terms in the operators of spin-orbit, spin-spin, and retarded interactions compared with the previously obtained expressions for these operators. We construct the operator of the dipole-dipole interaction of two neutral atoms located at an arbitrary separation.
Role of the Russell-McPherron Effect in the Acceleration of Relativistic Electrons
NASA Technical Reports Server (NTRS)
McPherron, R. L.; Baker, D. N.; Crooker, N. U.
2010-01-01
While it is well known that high fluxes of relativistic electrons in the Earth's radiation belts are associated with high-speed solar wind and its heightened geoeffectiveness,less known is the fact that the Russell McPherron(R M) effect strongly controls whether or not a given high-speed stream is geoffective. To test whether it then follows that the R M effect also strongly controls fluxes of relativistic electrons, we perform a superposed epoch analysis across corotating interaction regions (CIR) keyed on the interfaces between slow and fast wind. A total of 394 stream interfaces were identified in the years 1994-2006. Equinoctial interfaces were separated into four classes based on the R-M effect,that is, whether the solar wind on either side of the interface was either(geo)effective (E) or ineffective (I) depending on season and the polarity of the interplanetary magnetic field (IMF). Four classes of interface identified as II, IE, EI,and EE are possible. The classes IE and EI correspond to CIRs with polarity changes indicating passage through the heliospheric current sheet. To characterize the behavior of solar wind and magnetospheric variables, we produced maps of dynamic cumulative probability distribution functions (cdfs) as a function of time over 10-day intervals centered on the interfaces. These reveal that effective high-speed streams have geomagnetic activity nearly twice as strong as ineffective streams and electron fluxes a factor of 12 higher. In addition they show that an effective low-speed stream increases the flux of relativistic electrons before the interface so that an effective to ineffective transition results in lower fluxes after the interface.We conclude that the R-M effect plays a major role in organizing and sustaining a sequence of physical processes responsible for the acceleration of relativistic electrons.
The Effects of Different Teaching Approaches in Introductory Financial Accounting
ERIC Educational Resources Information Center
Chiang, Bea; Nouri, Hossein; Samanta, Subarna
2014-01-01
The purpose of the research is to examine the effect of the two different teaching approaches in the first accounting course on student performance in a subsequent finance course. The study compares 128 accounting and finance students who took introductory financial accounting by either a user approach or a traditional preparer approach to examine…
Relativistic heavy-atom effects on heavy-atom nuclear shieldings.
Lantto, Perttu; Romero, Rodolfo H; Gómez, Sergio S; Aucar, Gustavo A; Vaara, Juha
2006-11-14
The principal relativistic heavy-atom effects on the nuclear magnetic resonance (NMR) shielding tensor of the heavy atom itself (HAHA effects) are calculated using ab initio methods at the level of the Breit-Pauli Hamiltonian. This is the first systematic study of the main HAHA effects on nuclear shielding and chemical shift by perturbational relativistic approach. The dependence of the HAHA effects on the chemical environment of the heavy atom is investigated for the closed-shell X(2+), X(4+), XH(2), and XH(3) (-) (X=Si-Pb) as well as X(3+), XH(3), and XF(3) (X=P-Bi) systems. Fully relativistic Dirac-Hartree-Fock calculations are carried out for comparison. It is necessary in the Breit-Pauli approach to include the second-order magnetic-field-dependent spin-orbit (SO) shielding contribution as it is the larger SO term in XH(3) (-), XH(3), and XF(3), and is equally large in XH(2) as the conventional, third-order field-independent spin-orbit contribution. Considering the chemical shift, the third-order SO mechanism contributes two-thirds of the difference of approximately 1500 ppm between BiH(3) and BiF(3). The second-order SO mechanism and the numerically largest relativistic effect, which arises from the cross-term contribution of the Fermi contact hyperfine interaction and the relativistically modified spin-Zeeman interaction (FC/SZ-KE), are isotropic and practically independent of electron correlation effects as well as the chemical environment of the heavy atom. The third-order SO terms depend on these factors and contribute both to heavy-atom shielding anisotropy and NMR chemical shifts. While a qualitative picture of heavy-atom chemical shifts is already obtained at the nonrelativistic level of theory, reliable shifts may be expected after including the third-order SO contributions only, especially when calculations are carried out at correlated level. The FC/SZ-KE contribution to shielding is almost completely produced in the s orbitals of the heavy atom
Relativistic heavy-atom effects on heavy-atom nuclear shieldings
NASA Astrophysics Data System (ADS)
Lantto, Perttu; Romero, Rodolfo H.; Gómez, Sergio S.; Aucar, Gustavo A.; Vaara, Juha
2006-11-01
The principal relativistic heavy-atom effects on the nuclear magnetic resonance (NMR) shielding tensor of the heavy atom itself (HAHA effects) are calculated using ab initio methods at the level of the Breit-Pauli Hamiltonian. This is the first systematic study of the main HAHA effects on nuclear shielding and chemical shift by perturbational relativistic approach. The dependence of the HAHA effects on the chemical environment of the heavy atom is investigated for the closed-shell X2+, X4+, XH2, and XH3- (X =Si-Pb) as well as X3+, XH3, and XF3 (X =P-Bi) systems. Fully relativistic Dirac-Hartree-Fock calculations are carried out for comparison. It is necessary in the Breit-Pauli approach to include the second-order magnetic-field-dependent spin-orbit (SO) shielding contribution as it is the larger SO term in XH3-, XH3, and XF3, and is equally large in XH2 as the conventional, third-order field-independent spin-orbit contribution. Considering the chemical shift, the third-order SO mechanism contributes two-thirds of the difference of ˜1500ppm between BiH3 and BiF3. The second-order SO mechanism and the numerically largest relativistic effect, which arises from the cross-term contribution of the Fermi contact hyperfine interaction and the relativistically modified spin-Zeeman interaction (FC/SZ-KE), are isotropic and practically independent of electron correlation effects as well as the chemical environment of the heavy atom. The third-order SO terms depend on these factors and contribute both to heavy-atom shielding anisotropy and NMR chemical shifts. While a qualitative picture of heavy-atom chemical shifts is already obtained at the nonrelativistic level of theory, reliable shifts may be expected after including the third-order SO contributions only, especially when calculations are carried out at correlated level. The FC/SZ-KE contribution to shielding is almost completely produced in the s orbitals of the heavy atom, with values diminishing with the principal
Quantum-mechanical description of Lense-Thirring effect for relativistic scalar particles
NASA Astrophysics Data System (ADS)
Silenko, A. J.
2013-12-01
Exact expression for the Foldy-Wouthuysen Hamiltonian of scalar particles is used for a quantum-mechanical description of the relativistic Lense-Thirring effect. The exact evolution of the angular momentum operator in the Kerr field approximated by a spatially isotropic metric is found. The quantummechanical description of the full Lense-Thirring effect based on the Laplace-Runge-Lenz vector is given in the nonrelativistic and weak-field approximation. Relativistic quantum-mechanical equations for the velocity and acceleration operators are obtained. The equation for the acceleration defines the Coriolis-like and centrifugal-like accelerations and presents the quantum-mechanical description of the frame-dragging effect.
The Relativistic Effects on the Carbon-Carbon Coupling Constants Mediated by a Heavy Atom.
Wodyński, Artur; Malkina, Olga L; Pecul, Magdalena
2016-07-21
The (2)JCC, (3)JCC, and (4)JCC spin-spin coupling constants in the systems with a heavy atom (Cd, In, Sn, Sb, Te, Hg, Tl, Pb, Bi, and Po) in the coupling path have been calculated by means of density functional theory. The main goal was to estimate the relativistic effects on spin-spin coupling constants and to explore the factors which may influence them, including the nature of the heavy atom and carbon hybridization. The methods applied range, in order of reduced complexity, from the Dirac-Kohn-Sham (DKS) method (density functional theory with four-component Dirac-Coulomb Hamiltonian), through DFT with two- and one-component zeroth-order regular approximation (ZORA) Hamiltonians, to scalar effective core potentials (ECPs) with the nonrelativistic Hamiltonian. The use of DKS and ZORA methods leads to very similar results, and small-core ECPs of the MDF and MWB variety reproduce correctly the scalar relativistic effects. Scalar relativistic effects usually are larger than the spin-orbit coupling effects. The latter tend to influence the most the coupling constants of the sp(3)-hybridized carbon atoms and in compounds of the p-block heavy atoms. Large spin-orbit coupling contributions for the Po compounds are probably connected with the inverse of the lowest triplet excitation energy. PMID:27177252
NASA Astrophysics Data System (ADS)
Zaccari, D. G.; Ruiz de Azúa, M. C.; Melo, J. I.; Giribet, C. G.
2006-02-01
In the present work a set of formal relations connecting different approaches to calculate relativistic effects on magnetic molecular properties are proven. The linear response (LR) within the elimination of the small component (ESC), Breit Pauli, and minimal-coupling approaches are compared. To this end, the leading order ESC reduction of operators within the minimal-coupling four-component approach is carried out. The equivalence of all three approaches within the ESC approximation is proven. It is numerically verified for the NMR nuclear-magnetic shielding tensor taking HX and CH3X (X =Br,I) as model compounds. Formal relations proving the gauge origin invariance of the full relativistic effect on the NMR nuclear-magnetic shielding tensor within the LR-ESC approach are presented.
Relativistic scattering with a spatially dependent effective mass in the Dirac equation
Alhaidari, A. D.; Bahlouli, H.; Abdelmonem, M. S.; Al-Hasan, A.
2007-06-15
We formulate a relativistic algebraic method of scattering for systems with spatially dependent mass based on the J-matrix method. The reference Hamiltonian is the three-dimensional Dirac Hamiltonian but with a mass that is position-dependent with a constant asymptotic limit. Additionally, this effective mass distribution is locally represented in a finite dimensional function subspace. The spinor couples to spherically symmetric vector and pseudo scalar potentials that are short-range such that they are accurately represented by their matrix elements in the same finite dimensional subspace. We calculate the relativistic phase shift as a function of energy for a given configuration and study the effect of spatial variation of the mass on the energy resonance structure.
Relativistic effects on the bonding and properties of the hydrides of platinum
NASA Technical Reports Server (NTRS)
Dyall, Kenneth G.
1993-01-01
The ground state of PtH2 and several low-lying states of PtH(+) and PtH have been studied at the all-electron self-consistent-field level of theory to examine the importance of relativistic effects. The results of calculations based on Dirac-Hartree-Fock theory, nonrelativistic theory, and the spin-free no-pair relativistic approximation of Hess are compared to separate the effects of the spin-free terms and the spin-orbit terms of the Hamiltonian on the relativistic corrections to the molecular properties. Comparison is also made between first-order perturbation theory including the one-electron spin-free terms and the method of Hess to determine the size of effects beyond first order. It is found that the spin-orbit interaction significantly affects the properties and energetics of these molecules because of the participation of the Pt 5d orbitals in the bonding, and that effects beyond first order in perturbation theory are large. Any treatment of Pt compounds will have to include both the spin-free and spin-orbit interactions for an accurate description.
Dynamical gap generation in graphene nanoribbons: An effective relativistic field theoretical model
Chaves, A. J.; Paula, W. de; Frederico, T.; Lima, G. D.; Cordeiro, C. E.; Delfino, A.
2011-04-15
We show that the assumption of a nontrivial zero band gap for a graphene sheet within an effective relativistic field theoretical model description of interacting Dirac electrons on the surface of graphene describes the experimental band gap of graphene nanoribbons for a wide range of widths. The graphene band gap is dynamically generated, corresponding to a nontrivial gapless solution, found in the limit of an infinitely wide graphene ribbon. The nanoribbon band gap is determined by the experimental graphene work function.
A Non-Relativistic Look at the Compton Effect
ERIC Educational Resources Information Center
Feller, Steve; Giri, Sandeep; Zakrasek, Nicholas; Affatigato, Mario
2014-01-01
In a usual modern physics class the Compton effect is used as the pedagogical model for introducing relativity into quantum effects. The shift in photon wavelengths is usually introduced and derived using special relativity. Indeed, this works well for explaining the effect. However, in the senior author's class one of the student coauthors…
Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Demissie, Taye B; Ruud, Kenneth
2015-08-11
We present an implementation of the nuclear spin-rotation (SR) constants based on the relativistic four-component Dirac-Coulomb Hamiltonian. This formalism has been implemented in the framework of the Hartree-Fock and Kohn-Sham theory, allowing assessment of both pure and hybrid exchange-correlation functionals. In the density-functional theory (DFT) implementation of the response equations, a noncollinear generalized gradient approximation (GGA) has been used. The present approach enforces a restricted kinetic balance condition for the small-component basis at the integral level, leading to very efficient calculations of the property. We apply the methodology to study relativistic effects on the spin-rotation constants by performing calculations on XHn (n = 1-4) for all elements X in the p-block of the periodic table and comparing the effects of relativity on the nuclear SR tensors to that observed for the nuclear magnetic shielding tensors. Correlation effects as described by the density-functional theory are shown to be significant for the spin-rotation constants, whereas the differences between the use of GGA and hybrid density functionals are much smaller. Our calculated relativistic spin-rotation constants at the DFT level of theory are only in fair agreement with available experimental data. It is shown that the scaling of the relativistic effects for the spin-rotation constants (varying between Z(3.8) and Z(4.5)) is as strong as for the chemical shieldings but with a much smaller prefactor. PMID:26574455
The Negative Testing Effect and Multifactor Account
ERIC Educational Resources Information Center
Peterson, Daniel J.; Mulligan, Neil W.
2013-01-01
Across 3 experiments, we investigated the factors that dictate when taking a test improves subsequent memory performance (the "testing effect"). In Experiment 1, participants retrieving a set of targets during a retrieval practice phase ultimately recalled fewer of those targets compared with a group of participants who studied the…
Differential Effectiveness of Theoretical Accounts for Paradox.
ERIC Educational Resources Information Center
Forsyth, Nancy M.; Strong, Stanley R.
Paradoxical techniques in counseling consist of directing clients to practice the symptom which is causing them psychological distress. Both impression management theory and reactance theory have been advanced to explain the efficacy of such techniques. To examine the effectiveness of paradoxical techniques according to impression management and…
Dynamical Relativistic Effects in Quasielastic 1p -Shell Proton Knockout from O{sup 16}
Gao, J.; Anderson, B. D.; Aniol, K. A.; Auerbach, L.; Baker, F. T.; Berthot, J.; Bertin, P.-Y.; Boeglin, W. U.
2000-04-10
We have measured the cross section for quasielastic 1p -shell proton knockout in the {sup 16}O( e, e{sup '}p) reaction at {omega}=0.439 GeV and Q{sup 2}=0.8 (GeV/c){sup 2} for missing momentum P{sub miss}{<=}355 MeV /c . We have extracted the response functions R{sub L+TT} , R{sub T} , R{sub LT} , and the left-right asymmetry, A{sub LT} , for the 1p{sub 1/2} and the 1p{sub 3/2} states. The data are well described by relativistic distorted wave impulse approximation calculations. At large P{sub miss} , the structure observed in A{sub LT} indicates the existence of dynamical relativistic effects. (c) 2000 The American Physical Society.
The nucleon and Delta-resonance masses in relativistic chiral effective-field theory
V. Pascalutsa; M. Vanderhaeghen
2005-11-28
We study the chiral behavior of the nucleon and De-isobar masses within a manifestly covariant chiral effective-field theory, consistent with the analyticity principle. We compute the {pi} N and {pi}{Delta} one-loop contributions to the mass and field-normalization constant, and find that they can be described in terms of universal relativistic loop functions, multiplied by appropriate spin, isospin and coupling constants. We show that these relativistic one-loop corrections, when properly renormalized, obey the chiral power-counting and vanish in the chiral limit. The results including only the {pi} N-loop corrections compare favorably with the lattice QCD data for the pion-mass dependence of the nucleon and De masses, while inclusion of the {pi}/De loops tends to spoil this agreement.
NASA Astrophysics Data System (ADS)
Sanz, Javier; Debayle, Arnaud; Mima, K.
2012-11-01
An analytical study of the relativistic interaction of a linearly-polarized laser-field of ω frequency with highly overdense plasma is presented. Very intense high harmonics are generated produced by relativistic mirrors effects due to the relativistic electron plasma oscillation. Also, in agreement with 1D Particle-In-Cell Simulations (PICS), the model self-consistently explains the transition between the sheath inverse bremsstrahlung (SIB) absorption regime and the J×B heating (responsible for the 2ω electron bunches), as well as the mean electron energy.
Relativistic nuclear recoil, electron correlation and QED effects in highly charged Ar ions
NASA Astrophysics Data System (ADS)
Harman, Z.; Soria Orts, R.; Lapierre, A.; Crespo Lopez-Urrutia, J. R.; Artemyev, A. N.; Tupitsyn, I. I.; Jentschura, U. D.; Keitel, C. H.; Tawara, H.; Ullrich, J.; Shabaev, V. M.; Volotka, A. V.
2007-06-01
We have performed extensive theoretical studies on the 1s^22s^22p^2P3/2 -- ^2P1/2 M1 transition in Ar^13+ ions. Accurate radiative lifetimes are sensitive to QED corrections like the electron anomalous magnetic moment and to relativistic electron correlation effects. The lifetime of the P3/2 metastable state was determined to be 9.573(4)(5) ms (stat)(syst) [1] using the Heidelberg electron beam ion trap. Theoretical predictions cluster around a value that is significantly shorter than this high-precision experimental result. This discrepancy is presently unexplained. The wavelengths of the above transition in Ar^13+ and the 1s^22s2p ^3P1 -- ^3P2 M1 transition in Ar^14+ were compared for the isotopes ^36Ar and ^40Ar [2]. The observed mass shift has confirmed the relativistic theory of nuclear recoil effects in many-body systems. Our calculations, based on the fully relativistic recoil operator, are in excellent agreement with the measured results. [1] A. Lapierre, U.D. Jentschura, J.R. Crespo L'opez-Urrutia et al., Phys. Rev. Lett. 95, 183001 (2005); [2] R. Soria Orts, Z. Harman, J.R. Crespo L'opez-Urrutia et al., Phys. Rev. Lett. 97, 103002 (2006)
Artemyev, A. V.; Mourenas, D.; Krasnoselskikh, V. V.
2015-06-15
In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.
Hanni, Matti; Lantto, Perttu; Ilias, Miroslav; Jensen, Hans Jorgen Aagaard; Vaara, Juha
2007-10-28
Relativistic effects on the (129)Xe nuclear magnetic resonance shielding and (131)Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe(2) system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular interaction-induced binary chemical shift delta, the anisotropy of the shielding tensor Deltasigma, and the NQC constant along the internuclear axis chi( parallel) are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full leading-order one-electron Breit-Pauli perturbation theory (BPPT) is applied using a common gauge origin. Electron correlation effects are studied at the nonrelativistic (NR) coupled-cluster singles and doubles with perturbational triples [CCSD(T)] level of theory. The fully relativistic second-order Moller-Plesset many-body perturbation (DMP2) theory is used to examine the cross coupling between correlation and relativity on NQC. The same is investigated for delta and Deltasigma by BPPT with a density functional theory model. A semiquantitative agreement between the BPPT and DHF binary property curves is obtained for delta and Deltasigma in Xe(2). For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other hand, for the BPPT-based cross coupling of relativity and correlation. For chi( parallel), the fully relativistic DMP2 results obtain a correction for NR correlation effects beyond MP2. The computed temperature dependence of the second virial coefficient of the (129)Xe nuclear shielding is compared to experiment in Xe gas. Our best results, obtained with the piecewise approximation for the binary chemical shift combined with the
Inflationary back-reaction effects from Relativistic Quantum Geometry
NASA Astrophysics Data System (ADS)
Bellini, Mauricio
2016-03-01
We study the dynamics of scalar metric fluctuations in a non-perturbative variational formalism recently introduced, by which the dynamics of a geometrical scalar field θ, describes the quantum geometrical effects on a Weylian-like manifold with respect to a background Riemannian space-time. In this letter we have examined an example in the framework of inflationary cosmology. The resulting spectral predictions are in very good agreement with observations and other models of inflation.
Multireference and relativistic effects in NiH
NASA Astrophysics Data System (ADS)
Marian, Christel M.; Blomberg, Margareta R. A.; Siegbahn, Per E. M.
1989-09-01
Large multireference CI calculations have been performed for the ground state of NiH. The effects of relativity were investigated using both a variational (no pair) theory and perturbation theory. The largest CI calculations included up to 29 reference states and were performed at the contracted CI level. The calculated and experimental results (within parentheses) are for Re 2.76 a0 (2.76 a0), for ωe 1997 cm-1 (2003 cm-1) and for the dipole moment μ 2.32 D (2.4±0.1 D). The effects of relativity are -0.03 a0, +60 cm-1 and -0.3 D, respectively. The effects of going from a reference selection threshold of 0.05 to a selection threshold of 0.02 and a different set of CASSCF orbitals was before applying Davidson's correction +0.07 a0 for Re and about +30 cm-1 for ωe, and after applying this correction +0.06 a0 and -80 cm-1, respectively. The most accurate results for the dipole moment was obtained using the multireference ACPF method.
NASA Astrophysics Data System (ADS)
Li, Yang
The properties of the quark-gluon plasma are being thoroughly studied by utilizing relativistic heavy ion collisions. After its invention in astronomy in the 1950s, intensity interferometry was found to be a robust method to probe the spatial and temporal information of the nuclear collisions also. Although rescattering effects are negligible in elementary particle collisions, it may be very important for heavy ion collisions at RHIC and in the future LHC. Rescattering after production will modify the measured correlation function and make it harder to extract the dynamical information from data. To better understand the data which are dimmed by this final state process, we derive a general formula for intensity interferometry which can calculate rescattering effects easily. The formula can be used both non-relativistically and relativistically. Numerically, we found that rescattering effects on kaon interferometry for RHIC experiments can modify the measured ratio of the outward radius to the sideward radius, which is a sensitive probe to the equation of state, by as large as 15%. It is a nontrivial contribution which should be included to understand the data more accurately. The second part of this thesis is on the initial conditions in relativistic heavy ion collisions. Although relativistic hydrodynamics is successful in explaining many aspects of the data, it is only valid after some finite time after nuclear contact. The results depend on the choice of initial conditions which, so far, have been very uncertain. I describe a formula based on the McLerran-Venugopalan model to compute the initial energy density. The soft gluon fields produced immediately after the overlap of the nuclei can be expanded as a power series of the proper time t. Solving Yang-Mills equations with color current conservation can give us the analytical formulas for the fields. The local color charges on the transverse plane are stochastic variables and have to be taken care of by random
General relativistic effects in quantum interference of “clocks”
NASA Astrophysics Data System (ADS)
Zych, M.; Pikovski, I.; Costa, F.; Brukner, Č.
2016-06-01
Quantum mechanics and general relativity have been each successfully tested in numerous experiments. However, the regime where both theories are jointly required to explain physical phenomena remains untested by laboratory experiments, and is also not fully understood by theory. This contribution reviews recent ideas for a new type of experiments: quantum interference of “clocks”, which aim to test novel quantum effects that arise from time dilation. “Clock” interference experiments could be realised with atoms or photons in near future laboratory experiments.
Effects of Accountancy Internship on Subsequent Academic Performance.
ERIC Educational Resources Information Center
Kwong, K. S.; Lui, Gladie
1991-01-01
Explores the effects of accounting internships upon subsequent academic achievement. Reports that grade point averages and degree examination results of 10 Chinese University of Hong Kong students who had been interns were compared to scores of 236 accounting majors who had not. Concludes that internships increased student knowledge and…
Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule
NASA Astrophysics Data System (ADS)
Cloët, Ian C.; Bentz, Wolfgang; Thomas, Anthony W.
2016-01-01
In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q |≳0.5 GeV . The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei.
Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule.
Cloët, Ian C; Bentz, Wolfgang; Thomas, Anthony W
2016-01-22
In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q|≳0.5 GeV. The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei. PMID:26849589
NASA Astrophysics Data System (ADS)
Filatov, Michael; Cremer, Dieter
2003-03-01
For the quasi-relativistic normalized elimination of small component using an effective potential (NESC-EP) method, analytical energy gradients were developed, programmed, and implemented in a standard quantum chemical program package. NESC-EP with analytical gradients was applied to determine geometry, vibrational frequencies, and dissociation enthalpies of ferrocene, tungsten hexafluoride, and tungsten hexacarbonyle. Contrary to non-relativistic calculations and calculations carried out with RECPs for the same compounds, NESC-EP provided reliable molecular properties in good agreement with experiment. The computational power of NESC-EP results from the fact that reliable relativistic corrections are obtained at a cost level only slightly larger than that of a non-relativistic calculation.
NASA Astrophysics Data System (ADS)
Fiks, E. I.; Pivovarov, Yu. L.
2015-07-01
Theoretical analysis and representative calculations of angular and spectral distributions of X-ray Transition Radiation (XTR) by Relativistic Heavy Ions (RHI) crossing a radiator are presented taking into account both XTR absorption and RHI slowing-down. The calculations are performed for RHI energies of GSI, FAIR, CERN SPS and LHC and demonstrate the influence of XTR photon absorption as well as RHI slowing-down in a radiator on the appearance/disappearance of interference effects in both angular and spectral distributions of XTR.
Nonlinear positron-acoustic waves in fully relativistic degenerate plasmas
NASA Astrophysics Data System (ADS)
Hossen, M. A.; Mamun, A. A.
2016-03-01
The nonlinear positron-acoustic (PA) waves propagating in a fully relativistic electron-positron-ion (EPI) plasma (containing degenerate electrons and positrons, and immobile heavy ions) have been theoretically investigated. A fully relativistic hydrodynamic model, which is consistent with the relativistic principle has been used, and the reductive perturbation method is employed to derive the dynamical Korteweg-de Vries equation. The dynamics of electrons as well as positrons, and the presence of immobile heavy ions are taken into account. It is found that the effects of relativistic degeneracy of electrons and positrons, static heavy ions, plasma particles velocity, enthalpy, etc have significantly modified the basic properties of the PA solitary waves propagating in the fully relativistic EPI plasmas. The application of the results of our present work in astrophysical compact objects such as white dwarfs and neutron stars, etc are briefly discussed.
NASA Astrophysics Data System (ADS)
Marshall, R. A.; Nicolls, M. J.; Sanchez, E. R.; Lehtinen, N. G.; Neilson, J.
2014-12-01
An artificial beam of relativistic (0.5--10 MeV) electrons has been proposed as an active experiment in the ionosphere and magnetosphere, with applications to magnetic field-line tracing, studies of wave-particle interactions, and beam-atmosphere interactions. The beam-atmosphere interaction, while a scientific endeavor of its own, also provides key diagnostics for other experiments. We present results of Monte Carlo simulations of the interaction of a beam of relativistic electrons with the upper atmosphere as they are injected downwards from a notional high altitude (thermospheric / ionospheric) injection platform. The beam parameters, defined by realistic parameters of a compact linear accelerator, are used to create a distribution of thousands of electrons. Each electron is injected downwards from 300 km altitude towards the dense atmosphere, where it undergoes elastic and inelastic collisions, leading to secondary ionization, optical emissions, and X-rays via bremsstrahlung. Here we describe the Monte Carlo model and present calculations of diagnostic outputs, including optical emissions, X-ray fluxes, secondary ionization, and backscattered energetic electron fluxes. Optical emissions are propagated to the ground through the lower atmosphere, including the effects of atmospheric absorption and scattering, to estimate the brightness of the emission column for a given beam current and energy. Similarly, X-ray fluxes are propagated to hypothetical detectors on balloons and satellites, taking into account Compton scattering and photoabsorption. Secondary ionization is used to estimate the radar signal returns from various ground-based radar facilities. Finally, simulated backscattered electron fluxes are measured at the injection location. The simulation results show that for realizable accelerator parameters, each of these diagnostics should be readily detectable by appropriate instruments.
Observation of coherence in the time-reversed relativistic photoelectric effect.
Tashenov, S; Banaś, D; Beyer, H; Brandau, C; Fritzsche, S; Gumberidze, A; Hagmann, S; Hillenbrand, P-M; Jörg, H; Kojouharov, I; Kozhuharov, Ch; Lestinsky, M; Litvinov, Yu A; Maiorova, A V; Schaffner, H; Shabaev, V M; Spillmann, U; Stöhlker, Th; Surzhykov, A; Trotsenko, S
2014-09-12
The photoelectric effect has been studied in the regime of hard x rays and strong Coulomb fields via its time-reversed process of radiative recombination (RR). In the experiment, the relativistic electrons recombined into the 2p_{3/2} excited state of hydrogenlike uranium ions, and both the RR x rays and the subsequently emitted characteristic x rays were detected in coincidence. This allowed us to observe the coherence between the magnetic substates in a highly charged ion and to identify the contribution of the spin-orbit interaction to the RR process. PMID:25259973
NASA Astrophysics Data System (ADS)
Gross, Franz; Stadler, Alfred
2010-09-01
We present the effective range expansions for the 1S0 and 3S1 scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with χ2/Ndata≃1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.
Mercury Methylation by Cobalt Corrinoids: Relativistic Effects Dictate the Reaction Mechanism.
Demissie, Taye B; Garabato, Brady D; Ruud, Kenneth; Kozlowski, Pawel M
2016-09-12
The methylation of Hg(II) (SCH3 )2 by corrinoid-based methyl donors proceeds in a concerted manner through a single transition state by transfer of a methyl radical, in contrast to previously proposed reaction mechanisms. This reaction mechanism is a consequence of relativistic effects that lower the energies of the mercury 6p1/2 and 6p3/2 orbitals, making them energetically accessible for chemical bonding. In the absence of spin-orbit coupling, the predicted reaction mechanism is qualitatively different. This is the first example of relativity being decisive for the nature of an observed enzymatic reaction mechanism. PMID:27510509
Fountain effect of laser-driven relativistic electrons inside a solid dielectric
Sarkisov, G. S.; Jobe, D.; Spielman, R.; Leblanc, P.; Ivanov, V. V.; Sentoku, Y.; Yates, K.; Wiewior, P.; Bychenkov, V. Yu.
2011-09-26
Ultrafast interferometry with sub-ps resolution has been applied for the direct measurement of an electron density induced by a laser-driven relativistic electron beam inside a solid dielectric. The topology of the interference phase shift shows the signature of the ''fountain effect,'' a narrow electron beam that fans out from the propagation axis and heads back to the target surface. Two-dimensional particle-in-cell (PIC) computer simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields. The very low ionization, {approx}0.1%, observed after the heating pulse suggests a fast recombination at the sub-ps time scale.
Off-shell behavior of relativistic NN effective interactions and charge symmetry breaking
NASA Astrophysics Data System (ADS)
Gersten, A.; Thomas, A. W.; Weyrauch, M.
1990-04-01
We examine in detail the suggestion of Iqbal et al. for calculating the class-four charge symmetry breaking amplitude in n-p scattering. By simplifying to a model problem, we show explicitly that the approximation scheme is unreliable if a phenomenological, effective nucleon-nucleon T matrix is used. Our results have wider implications for observables calculated in relativistic impulse approximation calculations. They reinforce the observation made in the literature that the procedure of fitting only positive energy matrix elements can lead to an NN interaction whose off-shell behavior is incorrect.
Franz Gross, Alfred Stadler
2010-09-01
We present the effective range expansions for the 1S0 and 3S1 scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with \\chi^2/N{data} \\simeq 1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.
Caballero, O. L.; McLaughlin, G. C.; Surman, R. E-mail: olcaball@ncsu.edu E-mail: surmanr@union.edu
2012-02-01
Black hole (BH) accretion disks have been proposed as good candidates for a range of interesting nucleosynthesis, including the r-process. The presence of the BH influences the neutrino fluxes and affects the nucleosynthesis resulting from the interaction of the emitted neutrinos and hot outflowing material ejected from the disk. We study the impact of general relativistic effects on the neutrinos emitted from BH accretion disks. We present abundances obtained by considering null geodesics and energy shifts for two different disk models. We find that both the bending of the neutrino trajectories and the energy shifts have important consequences for the nucleosynthetic outcome.
Calculation of the relativistic Bloch correction to stopping power
NASA Technical Reports Server (NTRS)
Ahlen, S. P.
1982-01-01
Bloch's technique of joining the nonrelativistic Bethe and Bohr stopping-power expressions by taking into account wave-packet effects for close collisions is extended to the relativistic case. It is found that Bloch's nonrelativistic correction term must be modified and that charge asymmetric terms appear. Excellent agreement is observed by comparing the results of these calculations to recent data on the stopping power of relativistic heavy ions.
Nuclear electric dipole moment with relativistic effects in Xe and Hg atoms
Oshima, Sachiko; Fujita, Takehisa; Asaga, Tomoko
2007-03-15
The atomic electric dipole moment (EDM) is evaluated by considering the relativistic effects as well as nuclear finite size effects in Xe and Hg atomic systems. Due to Schiff's theorem, the first order perturbation energy of EDM is canceled out by the second order perturbation energy for the point nucleus. The nuclear finite size effects arising from the intermediate atomic excitations may be finite for deformed nucleus but it is extremely small. The finite size contribution of the intermediate nuclear excitations in the second order perturbation energy is completely canceled by the third order perturbation energy. As the results, the finite contribution to the atomic EDM comes from the first order perturbation energy of relativistic effects, and it amounts to around 0.3 and 0.4 percents of the neutron EDM d{sub n} for Xe and Hg, respectively, though the calculations are carried out with a simplified single-particle nuclear model. From this relation in Hg atomic system, we can extract the neutron EDM which is found to be just comparable with the direct neutron EDM measurement.
Multiple scattering calculations of relativistic electron energy loss spectra
NASA Astrophysics Data System (ADS)
Jorissen, K.; Rehr, J. J.; Verbeeck, J.
2010-04-01
A generalization of the real-space Green’s-function approach is presented for ab initio calculations of relativistic electron energy loss spectra (EELS) which are particularly important in anisotropic materials. The approach incorporates relativistic effects in terms of the transition tensor within the dipole-selection rule. In particular, the method accounts for relativistic corrections to the magic angle in orientation resolved EELS experiments. The approach is validated by a study of the graphite CK edge, for which we present an accurate magic angle measurement consistent with the predicted value.
Relativistic real-space multiple scattering calculations of EELS
NASA Astrophysics Data System (ADS)
Jorissen, K.; Rehr, J. J.; Sorini, A.; Levine, Z. H.
2006-03-01
We present an extension of the real space multiple scattering code FEFF8 for ab initio, relativistic calculations of electron energy loss spectra (EELS), which is applicable both to periodic and non-periodic systems. The approach explains the observed relativistic shifts in the magic angle. In addition, the method can account for experimental parameters such as collection and convergence angles of the microscope and sample orientation. We also discuss relativistic effects on inelastic electron scattering including the density correction to the stopping power. Our results are compared with other approaches and with experiment. B. Jouffrey, P. Schattschneider and C. Hebert, Ultramicroscopy 102, 61 (2004).
Non-relativistic Limit of Dirac Equations in Gravitational Field and Quantum Effects of Gravity
NASA Astrophysics Data System (ADS)
Wu, Ning
2006-03-01
Based on unified theory of electromagnetic interactions and gravitational interactions, the non-relativistic limit of the equation of motion of a charged Dirac particle in gravitational field is studied. From the Schrödinger equation obtained from this non-relativistic limit, we can see that the classical Newtonian gravitational potential appears as a part of the potential in the Schrödinger equation, which can explain the gravitational phase effects found in COW experiments. And because of this Newtonian gravitational potential, a quantum particle in the earth's gravitational field may form a gravitationally bound quantized state, which has already been detected in experiments. Three different kinds of phase effects related to gravitational interactions are studied in this paper, and these phase effects should be observable in some astrophysical processes. Besides, there exists direct coupling between gravitomagnetic field and quantum spin, and radiation caused by this coupling can be used to directly determine the gravitomagnetic field on the surface of a star.
The Effects of Pre-College Accounting on the College Accounting Student.
ERIC Educational Resources Information Center
Schroeder, Nicholas
1985-01-01
Through a research project, the author found that the attitudes of college accounting students toward high school accounting as the starting point for an accounting education and also the introductory financial accounting grades of college students are often closely associated with extensive accounting coursework completed prior to college. (CT)
Wang, H.; Snell, G.; Hemmers, O.; Sant'Anna, M. M.; Sellin, I.; Berrah, N.; Lindle, D. W.; Deshmukh, P. C.; Haque, N.; Manson, S. T.
2001-09-17
Two decades ago, it was predicted [Y.S.Kim et al., Phys.Rev.Lett.46, 1326 (1981)] that relativistic effects should alter the dynamics of the photoionization process in the vicinity of Cooper minima. The present experimental and theoretical study of the angular distributions of Xe 4d{sub 3/2} and 4d{sub 5/2} photoelectrons demonstrates this effect for the first time. The results clearly imply that relativistic effects are likely to be important for intermediate-Z atoms at most energies.
Magnetohydrodynamics of chiral relativistic fluids
NASA Astrophysics Data System (ADS)
Boyarsky, Alexey; Fröhlich, Jürg; Ruchayskiy, Oleg
2015-08-01
We study the dynamics of a plasma of charged relativistic fermions at very high temperature T ≫m , where m is the fermion mass, coupled to the electromagnetic field. In particular, we derive a magnetohydrodynamical description of the evolution of such a plasma. We show that, compared to conventional magnetohydronamics (MHD) for a plasma of nonrelativistic particles, the hydrodynamical description of the relativistic plasma involves new degrees of freedom described by a pseudoscalar field originating in a local asymmetry in the densities of left-handed and right-handed fermions. This field can be interpreted as an effective axion field. Taking into account the chiral anomaly we present dynamical equations for the evolution of this field, as well as of other fields appearing in the MHD description of the plasma. Due to its nonlinear coupling to helical magnetic fields, the axion field significantly affects the dynamics of a magnetized plasma and can give rise to a novel type of inverse cascade.
Using Instrumental Variables Properly to Account for Selection Effects
ERIC Educational Resources Information Center
Porter, Stephen R.
2012-01-01
Selection bias is problematic when evaluating the effects of postsecondary interventions on college students, and can lead to biased estimates of program effects. While instrumental variables can be used to account for endogeneity due to self-selection, current practice requires that all five assumptions of instrumental variables be met in order…
Sharma, R. P.; Gupta, M. K.
2006-11-15
In this paper, the authors have investigated the effect of ultra-intense laser beam filaments on stimulated Raman scattering (SRS) in unmagnetized plasma when relativistic and ponderomotive nonlinearities are operative. First, the filamentary dynamics of laser beam is studied. In these structures, the plasma wave generation and associated SRS process are studied. The effect of filamentation on SRS back reflectivity has been studied in detail. For the typical laser plasma parameters, i.e., laser beam Nd:YAG ({lambda}=1064 nm), laser beam radius=15 {mu}m, laser power flux=6x10{sup 17} W/cm{sup 2}, electron density=1.9x10{sup 19} per cm{sup 3}, the SRS reflectivity reduces by a factor 2.5 due to ponderomotive effects.
Vyas, Ashish Singh, Ram Kishor; Sharma, R. P.
2014-11-15
This paper presents a model to study the interplay between the stimulated Raman (SRS) and Brillouin scattering (SBS) along with the combined effect of relativistic and ponderomotive nonlinearities, at relativistic laser power. As the intense non-uniform laser beam propagates through the plasma, both the non-linearities are operative and modify the plasma refractive index in such a manner that one enhances the self-focusing (of the pump beam) caused by the other non-linearity. The interplay between the scattering processes (SRS and SBS) affects the pump filamentation process because of pump depletion and at the same time these scattering processes get modified due to this filamentation process. An impact of the filamentation process and coexistence of the scattering processes (SRS and SBS) on the back-reflectivity of scattered beams (SRS and SBS) has been explored and found that the back-reflectivity gets modified significantly. Results are also compared with the three wave interaction case (isolated SRS or SBS case)
Study of the Smith-Purcell effect in the relativistic regime
Doucas, G.; Dumitru, M.; Korschinck, G.
1995-12-31
We propose to investigate the spontaneous emission of radiation arising out of the interaction of a relativistic electron beam with a metallic grating (the Smith-Purcell effect). The work will concentrate, primarily, in the 50-120 {mu}m part of the infrared spectrum and will be an extension of the work begun by the Oxford-Dartmouth-Essex collaboration; one of the early objectives of the project will be to develop a quantitative understanding of the power spectrum of the emitted radiation over a wide range of emission angles. In particular, the limits of relativistic peaking of forward directed emission will be investigated. The electron beam will be produced by laser irradiation of a metallic cathode in the terminal of a small Van de Graff accelerator located in the Technische Universitaet, Muenchen. Beam energies will be in the range of 2 - 4 MeV. Initial tests on photoproduction of electrons have yielded 10 mA pulses with a width of about 20 ns. The electron pulse length is long enough to not only produce easily observed levels of spontaneous emission, but in principle gain due to stimulated emission should also be observable. Observation of gain is a second goal of the project. The manufacture of the grating chamber and the voltage tests on the accelerator will progress in parallel. This is a 3-year project and is supported, in part, by the British-German Academic Research Collaboration (ARC) program.
Spin Hall effect in two-dimensional systems within the relativistic phase shift model
NASA Astrophysics Data System (ADS)
Johansson, Annika; Herschbach, Christian; Fedorov, Dmitry V.; Henk, Jürgen; Mertig, Ingrid
2015-11-01
Recently, a relativistic phase shift model (RPSM) was introduced [D. V. Fedorov et al., Phys. Rev. B 88, 085116 (2013), 10.1103/PhysRevB.88.085116] to describe the skew-scattering mechanism of the spin Hall effect caused by impurities in bulk crystals. Here, we present its analog derived for two-dimensional (2D) systems. The proposed 2D-RPSM is applied to one-monolayer noble-metal films with various substitutional impurities and the obtained results are compared with those of corresponding first-principles calculations. We demonstrate that, in contrast to the three-dimensional RPSM, the considered model does not provide a sufficient qualitative description of the transport properties. Therefore, an ab initio treatment is necessary for the description of the spin Hall effect in two-dimensional crystals.
Statistics of neutrinos and relativistic effective degrees of freedom in the early universe
NASA Astrophysics Data System (ADS)
Iizuka, Jun; Kitabayashi, Teruyuki
2016-03-01
We study the effects of the presence of non-pure fermionic neutrinos on the relativistic effective degrees of freedom g∗ in the early universe. The statistics of neutrinos is transformed from Fermi-Dirac (FD) to Bose-Einstein (BE) via Maxwell-Boltzmann (MB) statistics. The equilibrium energy density of pure bosonic neutrinos is larger than the energy density of pure fermionic neutrinos. One may expect that the relation g∗FD < g∗MB < g∗BE. We show that this relation is not always satisfied with degenerate neutrinos. We discuss briefly the cosmological consequences of this transformation for dark matter problem as well as the baryon-photon ratio in the universe.
The gravitomagnetic interaction and its relationship to other relativistic gravitational effects
NASA Technical Reports Server (NTRS)
Nordtvedt, Kenneth
1991-01-01
To better understand the relationship between the expected precession rates of an orbiting gyroscope (GP-B) and other observable consequences in the solar system of relativistic, post-Newtonian gravity, a phenomenological model was developed of post-Newtonian gravity which presupposes the very minimum possible concerning the nature and foundations of the gravitational interaction. Solar system observations, chiefly interplanetary ranging, fix all the parameters in the phenomenological model to various levels of precision. This permits prediction of gyroscope precession rates to better than 10 pct. accuracy. A number of new precession terms are calculated which would exist if gravity were not a metric field phenomenon, but this would clash with other empirical observations of post-Newtonian effects in gravity. It is shown that gravitomagnetism, the post-Newtonian gravitational corrections to the interactions between moving matter, plays a ubiquitous role in determining a wide variety of gravitational effects, including the precession of orbiting gyroscopes.
Relativistic description of pair production of doubly heavy baryons in e{sup +}e{sup −} annihilation
Martynenko, A. P.; Trunin, A. M.
2015-05-15
Relativistic corrections in the pair production of S-wave doubly heavy diquarks in electron-positron annihilation were calculated on the basis of perturbative QCD and the quark model. The relativistic corrections to the wave functions for quark bound states were taken into account with the aid of the Breit potential in QCD. Relativistic effects change substantially the nonrelativistic cross sections for pair diquark production. The yield of pairs of (ccq) doubly heavy baryons at B factories was estimated.
Contrast effects in spontaneous evaluations: a psychophysical account.
Klauer, Karl Christoph; Teige-Mocigemba, Sarah; Spruyt, Adriaan
2009-02-01
In the affective-priming paradigm, target stimuli are preceded by evaluatively polarized prime stimuli and then are to be classified as either good or bad as fast as possible. The typical and robust finding is assimilation: Primes facilitate the processing of evaluatively consistent targets relative to evaluatively inconsistent targets. Nevertheless, contrast effects have repeatedly been observed. The authors propose a new psychophysical account of normal (assimilative) and reversed (contrastive) priming effects and test new predictions derived from it in 5 studies: In Studies 1 and 2, the authors' account is shown to provide a better explanation of contrastive effects in a priming paradigm with two primes than the traditional attentional account does. Furthermore, as predicted by the new account, contrast effects emerge at an intermediate stimulus-onset asynchrony (SOA, Study 3) and even with short SOAs when target onset takes participants by surprise (Study 4). Finally, the use of extremely valenced primes triggers corrective efforts (Study 5) as predicted. Implications for priming measures of evaluative associations are discussed. PMID:19159132
An interference account of the missing-VP effect
Häussler, Jana; Bader, Markus
2015-01-01
Sentences with doubly center-embedded relative clauses in which a verb phrase (VP) is missing are sometimes perceived as grammatical, thus giving rise to an illusion of grammaticality. In this paper, we provide a new account of why missing-VP sentences, which are both complex and ungrammatical, lead to an illusion of grammaticality, the so-called missing-VP effect. We propose that the missing-VP effect in particular, and processing difficulties with multiply center-embedded clauses more generally, are best understood as resulting from interference during cue-based retrieval. When processing a sentence with double center-embedding, a retrieval error due to interference can cause the verb of an embedded clause to be erroneously attached into a higher clause. This can lead to an illusion of grammaticality in the case of missing-VP sentences and to processing complexity in the case of complete sentences with double center-embedding. Evidence for an interference account of the missing-VP effect comes from experiments that have investigated the missing-VP effect in German using a speeded grammaticality judgments procedure. We review this evidence and then present two new experiments that show that the missing-VP effect can be found in German also with less restricting procedures. One experiment was a questionnaire study which required grammaticality judgments from participants without imposing any time constraints. The second experiment used a self-paced reading procedure and did not require any judgments. Both experiments confirm the prior findings of missing-VP effects in German and also show that the missing-VP effect is subject to a primacy effect as known from the memory literature. Based on this evidence, we argue that an account of missing-VP effects in terms of interference during cue-based retrieval is superior to accounts in terms of limited memory resources or in terms of experience with embedded structures. PMID:26136698
Hramov, A. E.; Koronovskii, A. A.; Kurkin, S. A.; Filatova, A. E.
2012-11-15
The report is devoted to the results of the numerical study of the virtual cathode (VC) formation conditions in the relativistic electron beam (REB) under the influence of the self-magnetic and external axial magnetic fields. The azimuthal instability of the relativistic electron beam leading to the formation of the vortex electron structure in the system was found out. This instability is determined by the influence of the self-magnetic fields of the relativistic electron beam, and it leads to the decrease of the critical value of the electron beam current (current when the non-stationary virtual cathode is formed in the drift space). The typical dependencies of the critical current on the external uniform magnetic field value were discovered. The effect of the beam thickness on the virtual cathode formation conditions was also analyzed.
Paranthaman, Selvarengan; Moon, Jiwon; Kim, Joonghan; Kim, Dong Eon; Kim, Tae Kyu
2016-04-01
Herein a performance assessment of density functionals used for calculating the structural and energetic parameters of bi- and trimetallic Ru-containing organometallic complexes has been performed. The performance of four popular relativistic effective core potentials (RECPs) has also been assessed. On the basis of the calculated results, the MN12-SX (range-separated hybrid functional) demonstrates good performance for calculating the molecular structures, while MN12-L (local functional) performs well for calculating the energetics, including that of the Ru-Ru bond breaking process. The choice of appropriate density functional is a crucial factor for calculating the energetics. The LANL08 demonstrates the lowest performance of the RECPs for calculating the molecular structures, especially the Ru-Ru bond length. PMID:26986051
Higher-order nonlocal effects of a relativistic ponderomotive force in high-intensity laser fields.
Iwata, Natsumi; Kishimoto, Yasuaki
2014-01-24
We have developed a new formula for a relativistic ponderomotive force of transversely localized laser fields based on the noncanonical Lie perturbation method by finding proper coordinates and gauges in the variational principle. The formula involves new terms represented by second and third spatial derivatives of the field amplitude, so that the ponderomotive force depends not only on the local field gradient, but also on the curvature and its variation. The formula is then applicable to a regime in which the conventional formula is hardly applied such that nonlocal and/or global extent of the field profile becomes important. The result can provide a theoretical basis for describing nonlinear laser-plasma interaction including such nonlocal effects, which is examined via particle-in-cell simulation of laser propagation in a plasma with a super Gaussian transverse field profile. PMID:24484146
Hussong, Matthias W; Hoffmeister, Wilhelm T; Rominger, Frank; Straub, Bernd F
2015-08-24
Salts of a copper and a silver carbene complex were prepared from dimesityl diazomethane, made possible by the steric shielding of the N-heterocyclic carbene (NHC) ancillary ligand IPr**. The mint-green complex [IPr**Ag=CMes2 ](+) [NTf2 ](-) is the first isolated silver carbene complex without heteroatom donor substituents. Single-crystal X-ray diffraction provides evidence for a predominant carbenoid character, and supports the postulation of such reactive species as intermediates in silver-catalyzed C-H activation reactions. The greenish yellow copper carbene complex [IPr**Cu=CMes2 ](+) [NTf2 ](-) has spectroscopic properties in between the isostructural silver complex and the already reported emerald green gold carbene complex. A comparison in the Group 11 series indicates that relativistic effects are responsible for the strong σ bond and the significant π back-bonding in the gold carbene moiety. PMID:26189567
Gross, Franz; Stadler, Alfred
2010-09-15
We present the effective range expansions for the {sup 1}S{sub 0} and {sup 3}S{sub 1} scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with {chi}{sup 2}/N{sub data{approx_equal}}1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.
Intense relativistic electron beam generation and prepulse effect in high power cylindrical diode
Roy, Amitava; Menon, R.; Mitra, S.; Kumar, D. D. P.; Kumar, Senthil; Sharma, Archana; Mittal, K. C.; Nagesh, K. V.; Chakravarthy, D. P.
2008-01-01
Intense gigawatt relativistic electron beam has been generated in a high power cylindrical diode in the presence of prepulse. A bipolar prepulse voltage, recorded at the diode, varies both in amplitude and time duration with the Marx generator voltage. It was found that only at the accelerating gap {<=}1.65 cm there is some shot to shot variation in the diode voltage and current for the same Marx generator voltage. The anode and cathode plasma expansion velocities were calculated using the perveance data. The plasma expands at 5 cm/{mu}s for 1.85 cm radial anode-cathode gap and the plasma velocity decreases for smaller gap. It was found that the effect of the prepulse is less pronounced in the cylindrical diode as compared to planar diode that allows one operation of the cylindrical diode with the gap {<=}1.85 cm.
NASA Astrophysics Data System (ADS)
Banerjee, Tanima; Deshmukh, P. C.; Manson, S. T.
2015-05-01
Accuracy in the study of the photoionization of heavy atomic systems requires the inclusion of both many-body effects (correlation) and relativistic interactions. The Relative Random Phase Approximation (RRPA) is a powerful theoretical model which includes many important electron corrections, along with relativity, in the calculation of atomic photoionization. Previously, valence photoionization in atomic mercury has been investigated using RRPA. To expand the understanding of the the correlation and relativistic effects further, photoionization of the intermediate subshells of atomic mercury, 4s, 4p, 4d, 4f, 5s and 5d, have been studied at different levels of truncations as a means of pinpointing the specific aspect(s) of correlation that is important in a given case. It has been found that the intermediate subshells are sensitive to the correlation and relativistic effects but not as significantly as in the case of valence shell photoionization. In this work we have systematically investigated the changes caused by relativistic and correlation effects on both dipole (E1) and quadrupole (E2) photoionization parameters for atomic mercury.
NASA Astrophysics Data System (ADS)
Gomez, Sergio S.; Maldonado, Alejandro; Aucar, Gustavo A.
2005-12-01
In this work an analysis of the electronic origin of relativistic effects on the isotropic dia- and paramagnetic contributions to the nuclear magnetic shielding σ(X ) for noble gases and heavy atoms of hydrogen halides is presented. All results were obtained within the 4-component polarization propagator formalism at different level of approach [random-phase approximation (RPA) and pure zeroth-order approximation (PZOA)], by using a local version of the DIRAC code. From the fact that calculations of diamagnetic contributions to σ within RPA and PZOA approaches for HX(X =Br,I,At) and rare-gas atoms are quite close each to other and the finding that the diamagnetic part of the principal propagator at the PZOA level can be developed as a series [S(Δ)], it was found that there is a branch of negative-energy "virtual" excitations that contribute with more than 98% of the total diamagnetic value even for the heavier elements, namely, Xe, Rn, I, and At. It contains virtual negative-energy molecular-orbital states with energies between -2mc2 and -4mc2. This fact can explain the excellent performance of the linear response elimination of small component (LR-ESC) scheme for elements up to the fifth row in the Periodic Table. An analysis of the convergency of S(Δ ) and its physical implications is given. It is also shown that the total contribution to relativistic effects of the innermost orbital (1s1/2) is by far the largest. For the paramagnetic contributions results at the RPA and PZOA approximations are similar only for rare-gas atoms. On the other hand, if the mass-correction contributions to σp are expressed in terms of atomic orbitals, a different pattern is found for 1s1/2 orbital contributions compared with all other s-type orbitals when the whole set of rare-gas atoms is considered.
Multiple carbon accounting to support just and effective climate policies
NASA Astrophysics Data System (ADS)
Steininger, Karl W.; Lininger, Christian; Meyer, Lukas H.; Muñoz, Pablo; Schinko, Thomas
2016-01-01
Negotiating reductions in greenhouse gas emission involves the allocation of emissions and of emission reductions to specific agents, and notably, within the current UN framework, to associated countries. As production takes place in supply chains, increasingly extending over several countries, there are various options available in which emissions originating from one and the same activity may be attributed to different agents along the supply chain and thus to different countries. In this way, several distinct types of national carbon accounts can be constructed. We argue that these accounts will typically differ in the information they provide to individual countries on the effects their actions have on global emissions; and they may also, to varying degrees, prove useful in supporting the pursuit of an effective and just climate policy. None of the accounting systems, however, prove 'best' in achieving these aims under real-world circumstances; we thus suggest compiling reliable data to aid in the consistent calculation of multiple carbon accounts on a global level.
Moreno-Torres, M.; Anguiano, M.; Grasso, M.; Van Giai, N.; Liang, H.; De Donno, V.
2010-06-15
Tensor effects in shell evolution are studied within the mean-field approach. Particular attention is paid to the analysis of the magic gaps in different regions of the nuclear chart, namely, Z,N=8, 20, and 28. Hartree-Fock calculations with Skyrme and Gogny interactions are performed where the tensor term has a zero and finite range, respectively. Results obtained with and without the tensor component are compared between them and with the experimental data, when available. To complete this analysis, the tensor effect is also investigated within the relativistic Hartree-Fock model, where the exchange of rho mesons and pions is taken into account. It turns out that the tensor effect in the evolution of the magic gaps can be more easily identified in the cases Z,N=8 and 20, whereas the interpretation of the effect is more complicated for Z or N= 28. Consequently, we indicate the regions defined by the magic numbers 8 and 20 as suitable for fitting the tensor parameters in a mean-field approach: We suggest to include explicitly the data associated to these gap evolutions in the fitting procedures. In general, with the parametrizations used in this work (which have not been fitted on these data), the mean-field results obtained with the tensor contribution do not reproduce the experimental trend, that is, the reduction of the gaps at 8 and 20 that is observed when going toward the drip lines. Since some of the considered nuclei have N=Z, a discussion will be devoted to the interpretation of the experimental data concerning these nuclei and to the Wigner-energy correction.
A study on the effects of relativistic heavy charged particles on the cellular microenvironment
NASA Astrophysics Data System (ADS)
Costes, Sylvain Vincent
This study was done under the National Aeronautics Space Administration (NASA) effort to assess the effect of cosmic radiation on astronauts during a 3 year mission to Mars. Carcinogenesis is known to be induced more efficiently by cosmic radiation. Our attention was turned towards one of the most efficient cosmic particles in inducing cancer, relativistic Fe, and focused in assessing its effect on the cellular microenvironment (ECM). Previous observations on mammary glands were showing irregularities in the immunoreactivity of the ECM protein laminin one hour after whole body irradiation with 1GeV/amu Fe ions for a dose of 0.8 Gy. This effect was not observed after 5 Gy γ-rays exposure. The rapidity of such a change suggested that the effect might be due to a physical event specific to relativistic charged particles (HZE), rather than a biological event. Our study showed that this effect is actually a complex and rapid response of the microenvironment to highly ionizing radiation. It involves a fast disruption of the basement membrane of the ECM induced by the highly localized ionization and reactive oxygen formation around the track of the Fe ion. This disruption triggers further chemical and biological responses involved in the remodeling of the laminin network in the basement membrane. A metalloproteinase is suspected to be the intermediate protease affecting laminin. The HZE effect on the microenvironment was seen in both mouse mammary glands and skin, but the laminin isoforms sensitive to Fe ions were different for each organ, with a clear disruption of laminin-1 network in skin and of laminin-5 in mammary glands. In addition, the laminin receptor integrins seem to be involved in this mechanism, but its contribution is unclear at this point. Finally, such studies suggest a shift from the concept of relative biological effectiveness (RBE) used in classical radiation biology since the effect is only seen with HZE at viable whole body doses. In addition, this
SAMPEX Relativistic Microbursts Observation
NASA Astrophysics Data System (ADS)
Liang, X.; Comess, M.; Smith, D. M.; Selesnick, R. S.; Sample, J. G.; Millan, R. M.
2012-12-01
Relativistic (>1 MeV) electron microburst precipitation is thought to account for significant relativistic electron loss. We present the statistical and spectral analysis of relativistic microbursts observed by the Proton/Electron Telescope (PET) on board the Solar Anomalous Magnetospheric Particle Explorer(SAMPEX) satellite from 1992 to 2004. Spectrally we find that microbursts are well fit by an exponential energy distribution in the 0.5-4 MeV range with a spectral e-folding energy of E0 < 375 keV. We also discuss the comparison of morning microbursts with events at midnight, which were first identified as microbursts by O'Brien et al. (2004). Finally, we compare the loss-rates due to microbursts and non-microburst precipitation during storm times and averaged over all times.
A quantum probability account of order effects in inference.
Trueblood, Jennifer S; Busemeyer, Jerome R
2011-01-01
Order of information plays a crucial role in the process of updating beliefs across time. In fact, the presence of order effects makes a classical or Bayesian approach to inference difficult. As a result, the existing models of inference, such as the belief-adjustment model, merely provide an ad hoc explanation for these effects. We postulate a quantum inference model for order effects based on the axiomatic principles of quantum probability theory. The quantum inference model explains order effects by transforming a state vector with different sequences of operators for different orderings of information. We demonstrate this process by fitting the quantum model to data collected in a medical diagnostic task and a jury decision-making task. To further test the quantum inference model, a new jury decision-making experiment is developed. Using the results of this experiment, we compare the quantum inference model with two versions of the belief-adjustment model, the adding model and the averaging model. We show that both the quantum model and the adding model provide good fits to the data. To distinguish the quantum model from the adding model, we develop a new experiment involving extreme evidence. The results from this new experiment suggest that the adding model faces limitations when accounting for tasks involving extreme evidence, whereas the quantum inference model does not. Ultimately, we argue that the quantum model provides a more coherent account for order effects that was not possible before. PMID:21951058
Weakly relativistic plasma expansion
Fermous, Rachid Djebli, Mourad
2015-04-15
Plasma expansion is an important physical process that takes place in laser interactions with solid targets. Within a self-similar model for the hydrodynamical multi-fluid equations, we investigated the expansion of both dense and under-dense plasmas. The weakly relativistic electrons are produced by ultra-intense laser pulses, while ions are supposed to be in a non-relativistic regime. Numerical investigations have shown that relativistic effects are important for under-dense plasma and are characterized by a finite ion front velocity. Dense plasma expansion is found to be governed mainly by quantum contributions in the fluid equations that originate from the degenerate pressure in addition to the nonlinear contributions from exchange and correlation potentials. The quantum degeneracy parameter profile provides clues to set the limit between under-dense and dense relativistic plasma expansions at a given density and temperature.
Siminos, E; Grech, M; Skupin, S; Schlegel, T; Tikhonchuk, V T
2012-11-01
The effective increase of the critical density associated with the interaction of relativistically intense laser pulses with overcritical plasmas, known as self-induced transparency, is revisited for the case of circular polarization. A comparison of particle-in-cell simulations to the predictions of a relativistic cold-fluid model for the transparency threshold demonstrates that kinetic effects, such as electron heating, can lead to a substantial increase of the effective critical density compared to cold-fluid theory. These results are interpreted by a study of separatrices in the single-electron phase space corresponding to dynamics in the stationary fields predicted by the cold-fluid model. It is shown that perturbations due to electron heating exceeding a certain finite threshold can force electrons to escape into the vacuum, leading to laser pulse propagation. The modification of the transparency threshold is linked to the temporal pulse profile, through its effect on electron heating. PMID:23214893
The list strength effect: a contextual competition account.
Diana, Rachel A; Reder, Lynne M
2005-10-01
Research on the list strength effect (LSE) has shown that learning some words on a list more strongly than others impairs memory for the weakly learned words when tested with a recall task. Norman (2002) demonstrated that the LSE also occurs within the recollection process of a recognition test. In this study, a mechanistic dual-process account of the LSE was tested that simultaneously makes predictions concerning additional sources of context in interference effects. In two experiments, we attempted to replicate Norman's (2002) findings and provide the basis for our modeling efforts. We found evidence for a recollection LSE in raw measures of responding, with memory performance also benefiting from reinstatement of perceptual characteristics at test. However, large differences in the hits between the lists were accompanied by small differences in false alarms, such that when d' is calculated, differences between the lists are not significant. We propose an account of the LSE whereby the actual effect of competition between items on the list is small, although present, and difficult to distinguish from large effects of bias due to the strength manipulations. We argue that our findings provide support for a mechanistic explanation of LSE that is based on competition of source activation and changes in the thresholds for responses. PMID:16532860
Seismology of adolescent neutron stars: Accounting for thermal effects and crust elasticity
NASA Astrophysics Data System (ADS)
Krüger, C. J.; Ho, W. C. G.; Andersson, N.
2015-09-01
We study the oscillations of relativistic stars, incorporating key physics associated with internal composition, thermal gradients and crust elasticity. Our aim is to develop a formalism which is able to account for the state-of-the-art understanding of the complex physics associated with these systems. As a first step, we build models using a modern equation of state including composition gradients and density discontinuities associated with internal phase transitions (like the crust-core transition and the point where muons first appear in the core). In order to understand the nature of the oscillation spectrum, we carry out cooling simulations to provide realistic snapshots of the temperature distribution in the interior as the star evolves through adolescence. The associated thermal pressure is incorporated in the perturbation analysis, and we discuss the presence of g -modes arising as a result of thermal effects. We also consider interface modes due to phase-transitions and the gradual formation of the star's crust and the emergence of a set of shear modes.
NASA Astrophysics Data System (ADS)
Tong, Xiao-Min; Chu, Shih-I.
1998-02-01
We present a self-interaction-free relativistic density-functional theory (DFT). The theory is based on the extension of our recent nonrelativistic DFT treatment with optimized effective potential (OEP) and self-interaction correction (SIC) [Phys. Rev. A 55, 3406 (1997)] to the relativistic domain. Such a relativistic OEP-SIC procedure yields an orbital-independent single-particle local potential with proper long-range Coulombic (-1/r) behavior. The method is applied to the ground-state energy calculations for atoms with Z=2-106. A comparison with the corresponding nonrelativistic OEP-SIC calculations and other relativistic calculations is made. It is shown that the ionization potentials (obtained from the highest occupied orbital energies) and individual orbital binding energies determined by the present relativistic OEP-SIC method agree well with the experimental data across the Periodic Table.
NASA Astrophysics Data System (ADS)
Gao, Xinliang; Li, Wen; Bortnik, Jacob; Thorne, Richard M.; Lu, Quanming; Ma, Qianli; Tao, Xin; Wang, Shui
2015-06-01
Superposed epoch analyses were performed on 193 significant relativistic electron flux dropout events, in order to study the roles of different solar wind parameters in driving the depletion of relativistic electrons, using ~16 years of data from the POES and GOES missions, and the OMNIWEB solar wind database. We find that the solar wind dynamic pressure and interplanetary magnetic field (IMF) Bz play key roles in causing the relativistic electron flux dropouts, but also that either large solar wind dynamic pressure or strong southward IMF Bz by itself is capable of producing the significant depletion of relativistic electrons. The relativistic electron flux dropouts occur not only when the magnetopause is compressed closer to the Earth but also when the magnetopause is located very far (> ~10 RE). Importantly, our results show that in addition to the large solar wind dynamic pressure, which pushes the magnetopause inward strongly and causes the electrons to escape from the magnetosphere, relativistic electrons can also be scattered into the loss cone and precipitate into the Earth's atmosphere during periods of strong southward IMF Bz, which preferentially provides a source of free energy for electromagnetic ion cyclotron (EMIC) wave excitation. This is supported by the fact that the strongest electron precipitation into the atmosphere is found in the dusk sector, where EMIC waves are typically observed in the high-density plasmasphere or plume and cause efficient electron precipitation down to ~1 MeV.
NASA Astrophysics Data System (ADS)
Sveshnikov, K. A.; Khomovskii, D. I.
2013-03-01
The behavior of electron energy levels in hydrogen-like atoms is studied while taking into account the nonperturbative interaction between the radiative component of the magnetic moment of a free electron Δ g free and the Coulomb field of an atomic nucleus with charge Z, including those with Z > 137. It is shown that for Zα ≪ 1 the energy-level shift is rather effectively determined through the matrix elements of the corresponding Dirac-Pauli operator with relativistic Coulomb wave functions. At the same time, for superheavy nuclei with Z ˜ 170, this shift, generated by Δ g free, is genuinely nonperturbative, behaves like ˜ Z 5 near the threshold of negative continuum, exceeds all the estimates of radiative corrections coming from vacuum polarization and electron self-energy known so far, and turns out to be at least of the same order as the effects of nuclear charge screening by filled electron shells.
Taking into account photofission effects in gamma-activation analysis
Dayvdov, M.G.; Kishel'gof, V.V.; Naumov, A.P.; Trukhov, A.V.
1986-11-01
The authors proposed a method for calculating the effect of photofission of U and Th, which is based on the well-known laws of physics of photofission and methods for calculating the activity of fission products. The authors compared the results of numerical calculations of the gamma spectra of photofission products with the measurements performed with a Ge (Li) detector with the spectra from activated model samples of U and Th. The method developed enables calculating the coefficients of interference and is also applicable to the solution of the problems of optimization of gamma activation analysis taking into account U and Th fission.
Teaching accountability: using client feedback to train effective family therapists.
Sparks, Jacqueline A; Kisler, Tiffani S; Adams, Jerome F; Blumen, Dale G
2011-10-01
The AAMFT Task Force on Core Competencies (Nelson et al., 2007) proposed that marriage and family therapy (MFT) educators teach and provide evidence of trainee competence beyond coursework and accrued clinical hours. This article describes the integration of a systematic client feedback protocol into an MFT-accredited program's curricula to address the call for outcome-based learning. Outcome management (OM) provides a framework for teaching and assessing trainee effectiveness. Continuous incorporation of client feedback embodies collaborative, strengths-based, integrative, and diversity-centered program values. Students learn a system for being accountable to clients, the profession, and service communities. PMID:22007779
Engine control techniques to account for fuel effects
Kumar, Shankar; Frazier, Timothy R.; Stanton, Donald W.; Xu, Yi; Bunting, Bruce G.; Wolf, Leslie R.
2014-08-26
A technique for engine control to account for fuel effects including providing an internal combustion engine and a controller to regulate operation thereof, the engine being operable to combust a fuel to produce an exhaust gas; establishing a plurality of fuel property inputs; establishing a plurality of engine performance inputs; generating engine control information as a function of the fuel property inputs and the engine performance inputs; and accessing the engine control information with the controller to regulate at least one engine operating parameter.
Imafuku, Yuji; Abe, Minori; Schmidt, Michael W.; Hada, Masahiko
2016-03-22
Methodologies beyond the Born–Oppenheimer (BO) approximation are nowadays important to explain high precision spectroscopic measurements. Most previous evaluations of the BO correction are, however, focused on light-element molecules and based on a nonrelativistic Hamiltonian, so no information about the BO approximation (BOA) breakdown in heavy-element molecules is available. The present work is the first to investigate the BOA breakdown for the entire periodic table, by considering scalar relativistic effects in the Diagonal BO correction (DBOC). In closed shell atoms, the relativistic EDBOC scales as Z1.25 and the nonrelativistic EDBOC scales as Z1.17, where Z is the atomic number. Hence, wemore » found that EDBOC becomes larger in heavy element atoms and molecules, and the relativistic EDBOC increases faster than nonrelativistic EDBOC. We have further investigated the DBOC effects on properties such as potential energy curves, spectroscopic parameters, and various energetic properties. The DBOC effects for these properties are mostly affected by the lightest atom in the molecule. Furthermore, in X2 or XAt molecule (X = H, Li, Na, K, Rb, and Cs) the effect of DBOC systematically decreases when X becomes heavier but in HX molecules, the effect of DBOC seems relatively similar among all the molecules.« less
Imafuku, Yuji; Abe, Minori; Schmidt, Michael W; Hada, Masahiko
2016-04-01
Methodologies beyond the Born-Oppenheimer (BO) approximation are nowadays important to explain high precision spectroscopic measurements. Most previous evaluations of the BO correction are, however, focused on light-element molecules and based on a nonrelativistic Hamiltonian, so no information about the BO approximation (BOA) breakdown in heavy-element molecules is available. The present work is the first to investigate the BOA breakdown for the entire periodic table, by considering scalar relativistic effects in the Diagonal BO correction (DBOC). In closed shell atoms, the relativistic EDBOC scales as Z(1.25) and the nonrelativistic EDBOC scales as Z(1.17), where Z is the atomic number. Hence, we found that EDBOC becomes larger in heavy element atoms and molecules, and the relativistic EDBOC increases faster than nonrelativistic EDBOC. We have further investigated the DBOC effects on properties such as potential energy curves, spectroscopic parameters, and various energetic properties. The DBOC effects for these properties are mostly affected by the lightest atom in the molecule. Hence, in X2 or XAt molecule (X = H, Li, Na, K, Rb, and Cs) the effect of DBOC systematically decreases when X becomes heavier but in HX molecules, the effect of DBOC seems relatively similar among all the molecules. PMID:27003510
Prerequisite Change and Its Effect on Intermediate Accounting Performance
ERIC Educational Resources Information Center
Huang, Jiunn; O'Shaughnessy, John; Wagner, Robin
2005-01-01
As of Fall 1996, San Francisco State University changed its introductory financial accounting course to focus on a "user's" perspective, de-emphasizing the accounting cycle. Anticipating that these changes could impair subsequent performance, the Department of Accounting instituted a new prerequisite for intermediate accounting: Students would…
Negative congruency effects: a test of the inhibition account.
Kiesel, Andrea; Berner, Michael P; Kunde, Wilfried
2008-03-01
Masked priming experiments occasionally revealed surprising effects: Participants responded slower for congruent compared to incongruent primes. This negative congruency effect (NCE) was ascribed to inhibition of prime-induced activation [Eimer, M., & Schlaghecken, F. (2003). Response faciliation and inhibition in subliminal priming. Biological Psychology, 64, 7-26.] that sets in if the prime activation is sufficiently strong. The current study tests this assumption by implementing manipulations designed to vary the amount of prime-induced activation in three experiments. In Experiments 1 and 3, NCEs were observed despite reduced prime-induced activation. Experiment 2 revealed no NCE with at least similar prime strength. Thus, the amount of prime activation did not predict whether or not NCEs occurred. The findings are discussed with regard to the inhibition account and the recently proposed account of mask-induced activation [cf. Lleras, A., & Enns, J. T. (2004). Negative compatibility or object updating? A cautionary tale of mask-dependent priming. Journal of Experimental Psychology: General, 133, 475-493; Verleger, R., Jaskowski, P., Aydemir, A., van der Lubbe, R. H. J., & Groen, M. (2004). Qualitative differences between conscious and nonconscious processing? On inverse priming induced by masked arrows. Journal of Experimental Psychology: General, 133, 494-515]. PMID:17188514
Effect of end reflections on conversion efficiency of coaxial relativistic backward wave oscillator
NASA Astrophysics Data System (ADS)
Teng, Yan; Chen, Changhua; Sun, Jun; Shi, Yanchao; Ye, Hu; Wu, Ping; Li, Shuang; Xiong, Xiaolong
2015-11-01
This paper theoretically investigates the effect of end reflections on the operation of the coaxial relativistic backward wave oscillator (CRBWO). It is found that the considerable enhancement of the end reflection at one end increases the conversion efficiency, but excessively large end reflections at both ends weaken the asynchronous wave-beam interaction and thus reduce the conversion efficiency. Perfect reflection at the post end significantly improves the interaction between the electron beam and the asynchronous harmonic so that the conversion efficiency is notably increased. Based on the theoretical research, the diffraction-CRBWO with the generated microwave diffracted and output through the front end of the coaxial slow wave structure cavity is proposed. The post end is conductively closed to provide the perfect reflection. This promotes the amplitude and uniformity of the longitudinal electric field on the beam transmission line and improves the asynchronous wave-beam interaction. In numerical simulations under the diode voltage and current of 450 kV and 5.84 kA, microwave generation with the power of 1.45 GW and the conversion efficiency of 55% are obtained at the frequency of 7.45 GHz.
Effect of end reflections on conversion efficiency of coaxial relativistic backward wave oscillator
Teng, Yan; Chen, Changhua; Sun, Jun; Shi, Yanchao; Ye, Hu; Wu, Ping; Li, Shuang; Xiong, Xiaolong
2015-11-07
This paper theoretically investigates the effect of end reflections on the operation of the coaxial relativistic backward wave oscillator (CRBWO). It is found that the considerable enhancement of the end reflection at one end increases the conversion efficiency, but excessively large end reflections at both ends weaken the asynchronous wave-beam interaction and thus reduce the conversion efficiency. Perfect reflection at the post end significantly improves the interaction between the electron beam and the asynchronous harmonic so that the conversion efficiency is notably increased. Based on the theoretical research, the diffraction-CRBWO with the generated microwave diffracted and output through the front end of the coaxial slow wave structure cavity is proposed. The post end is conductively closed to provide the perfect reflection. This promotes the amplitude and uniformity of the longitudinal electric field on the beam transmission line and improves the asynchronous wave-beam interaction. In numerical simulations under the diode voltage and current of 450 kV and 5.84 kA, microwave generation with the power of 1.45 GW and the conversion efficiency of 55% are obtained at the frequency of 7.45 GHz.
Roy, Amitava; Menon, R.; Mitra, S.; Kumar, D. D. P.; Kumar, Senthil; Sharma, V. K.; Patel, Ankur; Sharma, Archana; Mittal, K. C.; Nagesh, K. V.; Chakravarthy, D. P.
2008-07-01
Intense gigawatt relativistic electron beam generation studies were carried out in the presence of prepulse. Electron beams were generated using planar and annular graphite cathodes of various diameters at a fixed 25 mm anode-cathode gap. For the planar cathode, the beam parameters obtained are 340 keV, 24 kA, and 100 ns at a 680 A/cm{sup 2} current density. With an annular cathode, 346 keV, 10 kA, and 100 ns electron beam could be generated at a 3.4 kA/cm{sup 2} current density. The peak electric field in the diode varies from 58 to 138 kV/cm. A bipolar prepulse voltage has been recorded at the diode for both the cathodes. The amplitude of the negative prepulse voltage varies with the Marx generator voltage but the time duration remains same. The positive prepulse voltage varies both in amplitude and time duration with the Marx generator voltage. Some shot to shot variation in the diode voltage and current were recorded for the annular cathode due to the nonreproducibility of the prepulse generated plasma. It was found that the effect of prepulse is more pronounced in the cathode of larger diameter.
Effect of EMIC Wave Normal Angle Distribution on Relativistic Electron Scattering in Outer RB
NASA Technical Reports Server (NTRS)
Khazanov, G. V.; Gamayunov, K. V.
2007-01-01
We present the equatorial and bounce average pitch angle diffusion coefficients for scattering of relativistic electrons by the H+ mode of EMIC waves. Both the model (prescribed) and self consistent distributions over the wave normal angle are considered. The main results of our calculation can be summarized as follows: First, in comparison with field aligned waves, the intermediate and highly oblique waves reduce the pitch angle range subject to diffusion, and strongly suppress the scattering rate for low energy electrons (E less than 2 MeV). Second, for electron energies greater than 5 MeV, the |n| = 1 resonances operate only in a narrow region at large pitch-angles, and despite their greatest contribution in case of field aligned waves, cannot cause electron diffusion into the loss cone. For those energies, oblique waves at |n| greater than 1 resonances are more effective, extending the range of pitch angle diffusion down to the loss cone boundary, and increasing diffusion at small pitch angles by orders of magnitude.
NASA Technical Reports Server (NTRS)
Ashby, Neil
1987-01-01
The results of an investigation of relativistic effects which have an influence on the determination of GM sub E (M sub E is the mass of the Earth, G is the Newtonian gravitaional constant) are summarized. The detailed arguments and derivations are discussed. The Parametrized Post-Newtonian (PPN) coordinates; Eddington-Clark (EC) coordinates; a coordinate system based on barycentric dynamical time (TBC coordinates); and Local Inertial coordinates are discussed.
NASA Astrophysics Data System (ADS)
Metaxas, Dimitrios
2008-09-01
I calculate the first corrections to the dynamical preexponential factor of the bubble nucleation rate for a relativistic first-order phase transition in an expanding cosmological background by estimating the effects of the Hubble expansion rate on the critical bubbles of Langer’s statistical theory of metastability. I also comment on possible applications and problems that arise when one considers the field theoretical extensions of these results (the Coleman De Luccia and Hawking-Moss instantons and decay rates).
Cold Nuclear Matter Effects on Heavy Quark Production in Relativistic Heavy Ion Collisions
NASA Astrophysics Data System (ADS)
Durham, John Matthew
2011-12-01
The experimental collaborations at the Relativistic Heavy Ion Collider (RHIC) have established that dense nuclear matter with partonic degrees of freedom is formed in collisions of heavy nuclei at 200 GeV. Information from heavy quarks has given significant insight into the dynamics of this matter. Charm and bottom quarks are dominantly produced by gluon fusion in the early stages of the collision, and thus experience the complete evolution of the medium. The production baseline measured in p + p collisions can be described by fixed order plus next to leading log perturbative QCD calculations within uncertainties. In central Au+Au collisions, suppression has been measured relative to the yield in p + p scaled by the number of nucleon-nucleon collisions, indicating a significant energy loss by heavy quarks in the medium. The large elliptic flow amplitude v2 provides evidence that the heavy quarks flow along with the lighter partons. The suppression and elliptic flow of these quarks are in qualitative agreement with calculations based on Langevin transport models that imply a viscosity to entropy density ratio close to the conjectured quantum lower bound of 1/4pi. However, a full understanding of these phenomena requires measurements of cold nuclear matter (CNM) effects, which should be present in Au+Au collisions but are difficult to distinguish experimentally from effects due to interactions with the medium. This thesis presents measurements of electrons at midrapidity from the decays of heavy quarks produced in d+Au collisions at RHIC. A significant enhancement of these electrons is seen at a transverse momentum below 5 GeV/c, indicating strong CNM effects on charm quarks that are not present for lighter quarks. A simple model of CNM effects in Au+Au collisions suggests that the level of suppression in the hot nuclear medium is comparable for all quark flavors.
Criteria for Determination of Material Control and Accountability System Effectiveness
John Wright
2008-03-01
The Nevada Test Site (NTS) is a test bed for implementation of the Safeguards First Principles Initiative (SFPI), a risk-based approach to Material Control & Accountability (MC&A) requirements. The Comprehensive Assessment of Safeguards Strategies (COMPASS) model is used to determine the effectiveness of MC&A systems under SFPI. Under this model, MC&A is divided into nine primary elements. Each element is divided into sub-elements. Then each sub-element is assigned two values, effectiveness and contribution, that are used to calculate the rating. Effectiveness is a measure of subelement implementation and how well it meets requirements. Contribution is a relative measure of the importance, and functions as a weighting factor. The COMPASS model provides the methodology for calculation of sub-element and element ratings, but not the actual criteria. Each site must develop its own criteria. For the rating to be meaningful, the effectiveness criteria must be objective and based on explicit, measurable criteria. Contribution (weights) must reflect the importance within the MC&A program. This paper details the NTS approach to system effectiveness and contribution values, and will cover the following: the basis for the ratings, an explanation of the contribution “weights,” and the objective, performance based effectiveness criteria. Finally, the evaluation process will be described.
Relativistic Doppler Beaming and Misalignments in AGN Jets
NASA Astrophysics Data System (ADS)
Singal, Ashok K.
2016-08-01
Radio maps of active galactic nuclei often show linear features, called jets, on both parsec and kiloparsec scales. These jets supposedly possess relativistic motion and are oriented close to the line of sight of the observer, and accordingly the relativistic Doppler beaming makes them look much brighter than they really are in their respective rest frames. The flux boosting due to the relativistic beaming is a very sensitive function of the jet orientation angle, as seen by the observer. Sometimes, large bends are seen in these jets, with misalignments being 90° or more, which might imply a change in the orientation angle that should cause a large change in the relativistic beaming factor. Hence, if relativistic beaming does play an important role in these jets such large bends should usually show high contrast in the brightness of the jets before and after the bend. It needs to be kept in mind that sometimes a small intrinsic change in the jet angle might appear as a much larger misalignment due to the effects of geometrical projection, especially when seen close to the line of sight. What really matters are the initial and final orientation angles of the jet with respect to the observer’s line of sight. Taking the geometrical projection effects properly into account, we calculate the consequences of the presumed relativistic beaming and demonstrate that there ought to be large brightness ratios in jets before and after the observed misalignments.
Abedi, Samira; Dorranian, Davoud; Abari, Mehdi Etehadi; Shokri, Babak
2011-09-15
In this paper, the effect of weakly relativistic ponderomotive force in the interaction of intense laser pulse with nonisothermal, underdense, collisional plasma is studied. Ponderomotive force modifies the electron density and temperature distribution. By considering the weakly relativistic effect and ohmic heating of plasma electrons, the nonlinear dielectric permittivity of plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. It is shown that with considering the ohmic heating of electrons and collisions, the effect of ponderomotive force in weakly relativistic regime leads to steepening the electron density profile and increases the temperature of plasma electrons noticeably. Bunches of electrons in plasma become narrower. By increasing the laser pulse strength, the wavelength of density oscillations decreases. In this regime of laser-plasma interaction, electron temperature increases sharply by increasing the intensity of laser pulse. The amplitude of electric and magnetic fields increases by increasing the laser pulse energy while their wavelength decreases and they lost their sinusoidal form.
Relativistic interactions and realistic applications
Hoch, T.; Madland, D.; Manakos, P.; Mannel, T.; Nikolaus, B.A.; Strottman, D. |
1992-12-31
A four-fermion-coupling Lagrangian (relativistic Skyrme-type) interaction has been proposed for relativistic nuclear structure calculations. This interaction, which has the merit of simplicity, is from the outset tailored as an effective interaction for relativistic Hartree-Fock calculations. Various extensions of such a model are discussed and compared with Walecka`s meson-nucleon mean field approach. We also present results of the calculation of nuclear ground state properties with an extended (density dependent) version of the four fermion interaction in a relativistic Hartree-Fock approximation.
Relativistic mean field calculations in neutron-rich nuclei
Gangopadhyay, G.; Bhattacharya, Madhubrata; Roy, Subinit
2014-08-14
Relativistic mean field calculations have been employed to study neutron rich nuclei. The Lagrange's equations have been solved in the co-ordinate space. The effect of the continuum has been effectively taken into account through the method of resonant continuum. It is found that BCS approximation performs as well as a more involved Relativistic Continuum Hartree Bogoliubov approach. Calculations reveal the possibility of modification of magic numbers in neutron rich nuclei. Calculation for low energy proton scattering cross sections shows that the present approach reproduces the density in very light neutron rich nuclei.
NASA Astrophysics Data System (ADS)
Kellö, Vladimir; Sadlej, Andrzej J.; Hess, Bernd A.
1996-08-01
Relativistic effects and electron correlation effects on the dipole moments of the coinage metal hydrides are investigated and compared employing one-component (scalar) relativistic approximations based on the mass-velocity and Darwin operator and, alternatively, the Douglas-Kroll-transformed spin-averaged no-pair Hamiltonian. The former of the two operators is found to perform quite accurately for CuH and AgH. For AuH the limits of the Pauli approximation seem to be reached, as can be inferred from a comparison with the values obtained within the spin-averaged Douglas-Kroll no-pair formalism. The coupled cluster calculations in the Douglas-Kroll no-pair approximation for relativistic effects establish the dipole moment values of the coinage metal hydrides as equal to 1.05 a.u. for CuH, 1.14 a.u. for AgH and 0.52 for AuH. The corresponding non-relativistic results are 1.14 a.u., 1.36 a.u., and 1.22 a.u., respectively. Some formal problems arising in applications of the Douglas-Kroll no-pair approximation are discussed. It is shown that the Hellmann-Feynman theorem leads to a rather complicated form of the first-order energy change due to external perturbation. The usual expectation value formula is, however, valid through terms proportional to 1/c4 and can be used in most applications. The invariance property with respect to a shift in the external potential is addressed for the Douglas-Kroll no-pair approximation in a finite basis set.
NASA Astrophysics Data System (ADS)
Bhuyan, M.; Panda, R. N.; Routray, T. R.; Patra, S. K.
2010-12-01
In the framework of relativistic mean field (RMF) theory, we have calculated the density distribution of protons and neutrons for Ca40,42,44,48 with NL3 and G2 parameter sets. The microscopic proton-nucleus optical potentials for p+Ca40,42,44,48 systems are evaluated from the Dirac nucleon-nucleon scattering amplitude and the density of the target nucleus using relativistic-Love-Franey and McNeil-Ray-Wallace parametrizations. We have estimated the scattering observables, such as the elastic differential scattering cross section, analyzing power and the spin observables with the relativistic impulse approximation (RIA). The results have been compared with the experimental data for a few selective cases and we find that the use of density as well as the scattering matrix parametrizations are crucial for the theoretical prediction.
Bhuyan, M.; Panda, R. N.; Routray, T. R.; Patra, S. K.
2010-12-15
In the framework of relativistic mean field (RMF) theory, we have calculated the density distribution of protons and neutrons for {sup 40,42,44,48}Ca with NL3 and G2 parameter sets. The microscopic proton-nucleus optical potentials for p+{sup 40,42,44,48}Ca systems are evaluated from the Dirac nucleon-nucleon scattering amplitude and the density of the target nucleus using relativistic-Love-Franey and McNeil-Ray-Wallace parametrizations. We have estimated the scattering observables, such as the elastic differential scattering cross section, analyzing power and the spin observables with the relativistic impulse approximation (RIA). The results have been compared with the experimental data for a few selective cases and we find that the use of density as well as the scattering matrix parametrizations are crucial for the theoretical prediction.
Bulk resonance absorption induced by relativistic effects in laser-plasma interaction
Ding Wenjun; Sheng, Z.-M.; Zhang, J.; Yu, M. Y.
2009-04-15
Resonance absorption in relativistic laser-plasma interaction is studied via two-dimensional particle-in-cell simulation. As the laser intensity increases from the linear regime, the absorption rate first decreases due to relativistic modulation of the electron plasma oscillations excited at the mode conversion layer. However, the trend reverses after a critical intensity. The reversal can be attributed to the fact that the relativistic critical layer depends on the local intensity of the laser pulse, so that instead of occurring in a thin layer, resonance absorption occurs in a plasma bulk region, leading absorption rate increase. The reflected-light spectrum also shows broadening and splitting of the harmonics at high laser intensities, which can be attributed to critical-surface oscillations driven by the laser ponderomotive force.
Potential Energy Curves in the CASSCF/CASPT2 and FS-MR-CC Methods: The Role of Relativistic Effects.
Barysz, Maria
2016-04-12
Ab initio CASSCF/CASPT2 calculations for the electronic ground and for a wide range of excited states of Li2 and Na2 dimers are presented. The computed spectroscopic parameters agree very well with the experimental data. This indicates that the old CASSCF/CASPT2 method can be as successfully applied to study excited states of molecules as recently developed the multireference Fock-space coulped-cluster method. The role of relativistic effects in the correct description of the potential energy curves has been investigated using as an example the SiAu molecule. The accuracy of the new infinite-order two-component relativistic method has been studied and its advantage over the Douglas-Kroll-Hess method demonstrated. PMID:26914182
Krushelnick, K.; Dangor, A. E.; Mangles, S. P. D.; Rozmus, W.; Wagner, U.; Habara, H.; Norreys, P. A.; Beg, F. N.; Wei, M. S.; Bochkarev, S. G.; Clark, E. L.; Gopal, A.; Evans, R. G.; Robinson, A. P. L.; Tatarakis, M.; Zepf, M.
2008-03-28
Experiments were performed in which intense laser pulses (up to 9x10{sup 19} W/cm{sup 2}) were used to irradiate very thin (submicron) mass-limited aluminum foil targets. Such interactions generated high-order harmonic radiation (greater than the 25th order) which was detected at the rear of the target and which was significantly broadened, modulated, and depolarized because of passage through the dense relativistic plasma. The spectral modifications are shown to be due to the laser absorption into hot electrons and the subsequent sharply increasing relativistic electron component within the dense plasma.
NASA Technical Reports Server (NTRS)
Gamayunov, K. V.; Khazanov, G. V.
2007-01-01
We consider the effect of oblique EMIC waves on relativistic electron scattering in the outer radiation belt using simultaneous observations of plasma and wave parameters from CRRES. The main findings can be s ummarized as follows: 1. In 1comparison with field-aligned waves, int ermediate and highly oblique distributions decrease the range of pitc h-angles subject to diffusion, and reduce the local scattering rate b y an order of magnitude at pitch-angles where the principle absolute value of n = 1 resonances operate. Oblique waves allow the absolute va lue of n > 1 resonances to operate, extending the range of local pitc h-angle diffusion down to the loss cone, and increasing the diffusion at lower pitch angles by orders of magnitude; 2. The local diffusion coefficients derived from CRRES data are qualitatively similar to the local results obtained for prescribed plasma/wave parameters. Conseq uently, it is likely that the bounce-averaged diffusion coefficients, if estimated from concurrent data, will exhibit the dependencies similar to those we found for model calculations; 3. In comparison with f ield-aligned waves, intermediate and highly oblique waves decrease th e bounce-averaged scattering rate near the edge of the equatorial lo ss cone by orders of magnitude if the electron energy does not excee d a threshold (approximately equal to 2 - 5 MeV) depending on specified plasma and/or wave parameters; 4. For greater electron energies_ ob lique waves operating the absolute value of n > 1 resonances are more effective and provide the same bounce_averaged diffusion rate near the loss cone as fiel_aligned waves do.
The effect of ULF compressional modes and field line resonances on relativistic electron dynamics
NASA Astrophysics Data System (ADS)
Degeling, A. W.; Rankin, R.; Kabin, K.; Marchand, R.; Mann, I. R.
2007-04-01
The adiabatic, drift-resonant interaction between relativistic, equatorially mirroring electrons and a ULF compressional wave that couples to a field line resonance (FLR) is modelled. Investigations are focussed on the effect of azimuthal localisation in wave amplitude on the electron dynamics. The ULF wave fields on the equatorial plane (r, φ) are modelled using a box model [Zhu, X., Kivelson, M.G., 1988. Analytic formulation and quantitative solutions of the coupled ULF wave problem. J. Geophys. Res. 93(A8), 8602-8612], and azimuthal variations are introduced by adding a discrete spectrum of azimuthal modes. Electron trajectories are calculated using drift equations assuming constant magnetic moment M, and the evolution of the distribution function f(r,φ,M,t) from an assumed initial condition is calculated by assuming f remains constant along electron trajectories. The azimuthal variation in ULF wave structure is shown to have a profound effect on the electron dynamics once a threshold in azimuthal variation is exceeded. Electron energy changes occur that are significantly larger than the trapping width corresponding to the maximum wave amplitude. We show how this can be explained in terms of the overlap of multiple resonance islands, produced by the introduction of azimuthal amplitude variation. This anomalous energisation is characterised by performing parameter scans in the modulation amplitude ɛ and the wave electric field. A simple parametric model for the threshold is shown to give reasonable agreement with the threshold observed in the electron dynamics model. Above the threshold, the radial transport averaged over φ is shown to become diffusive in nature over a timescale of about 25 wave periods. The anomalous energisation described in this paper occurs over the first 15 wave periods, indicating the importance of convective transport in this process.
Maldonado, Alejandro F; Aucar, Gustavo A
2014-09-11
The reference values for NMR magnetic shieldings, σ(ref), are of the highest importance when theoretical analysis of chemical shifts are envisaged. The fact that the nonrelativistically valid relationship among spin-rotation constants and magnetic shieldings is not any longer valid for heavy atoms requires that the search for σ(ref) for such atoms needs new strategies to follow. We present here results of σ(ref) that were obtained by applying our own simple procedure which mixes accurate experimental chemical shifts (δ) and theoretical magnetic shieldings (σ). We calculated σ(Sn) and σ(Pb) in a family of heavy-halogen-containing molecules. We found out that σ(ref)[Sn;Sn(CH3)4] in gas phase should be close to 3864.11 ± 20.05 ppm (0.5%). For Pb atom, σ(ref)[Pb;Pb(CH3)4] should be close to 14475.1 ± 500.7 ppm. Such theoretical values correspond to calculations with the relativistic polarization propagator method, RelPPA, at the RPA level of approach. They are closer to experimental values as compared to those obtained applying few different functionals such as PBE0, B3LYP, BLYP, BP86, KT2, and KT3 of the density functional theory, DFT. We studied tin and lead shieldings of the XY(4-n)Z(n) (X = Sn, Pb; Y, Z = H, F, Cl, Br, I) and PbH(4-n)I(n) (n = 0, 1, 2, 3, 4) family of compounds with four-component functionals as implemented in the DIRAC code. For these systems results of calculations with RelPPA-RPA are more reliable than DFT ones. We argue about why those DFT functionals must be modified in order to obtain more accurate results of NMR magnetic shieldings within the relativistic regime: first, there is a dependence among both electron-correlation and relativistic effects that should be introduced in some way in the functionals; and second, the DIRAC code uses standard nonrelativistic functionals and the functionals B3LYP and PBE0 were parametrized only with data taken from light elements. It can explain why they are not able to properly introduce
On Radiative Acceleration of Relativistic Jets
NASA Astrophysics Data System (ADS)
Inoue, S.; Takahara, F.
1997-10-01
The formation and acceleration of relativistic jets by radiative forces in black hole systems are investigated. Under a variety of circumstances, we calculate the bulk acceleration and radiative cooling of a confined plasma cell, immersed in different types of radiation fields and interacting by Compton scattering. Both non-relativistic (cold) and relativistic (hot) jet plasma, comprising mixtures of electron-proton and electron-positron components, are treated. We pay attention to some conceivable effects, previously neglected, which may possibly enhance the bulk acceleration; among them are an anisotropically radiating accretion disk surface, beamed secondary radiation from the inner jet, and scattering in the energy dependent Klein-Nishina regime. Our results are discussed in the context of relativistic jets in active galactic nuclei and Galactic black hole candidates, and the conditions necessary for successfully reproducing their observed properties are highlighted. In particular, the velocities of the recently discovered superluminal jets in Galactic black hole candidates (Lorentz factors of Γ ~ 2.5) are readily and very robustly accounted for if the jet is composed primarily of electron-positron pairs and the disk luminosity is near the Eddington value; the jet kinetic power can be consistent with optical depth and pair annihilation constraints. On the other hand, severe difficulty is met in attaining the velocities of AGN jets (Γ ~ 10), which can only be realized when a significant amount of beamed secondary radiation is present. We also contemplate additional important issues, such as global energetics.
Lipparini, Filippo; Gauss, Jürgen
2016-09-13
We present an implementation of the complete active space-self-consistent field (CASSCF) method specifically designed to be used in four-component scalar relativistic calculations based on the spin-free Dirac-Coulomb (SFDC) Hamiltonian. Our implementation takes full advantage of the properties of the SFDC Hamiltonian that allow us to use real algebra and to exploit point-group and spin symmetry to their full extent while including in a rigorous way scalar relativistic effects in the treatment. The SFDC-CASSCF treatment is more expensive than its non-relativistic counterpart only in the orbital optimization step, while exhibiting the same computational cost for the rate-determining full configuration interaction part. The numerical aspects are discussed, and the capabilities of the SFDC-CASSCF methodology are demonstrated through a pilot application. PMID:27464026
Fluid dynamical description of relativistic nuclear collisions
NASA Technical Reports Server (NTRS)
Nix, J. R.; Strottman, D.
1982-01-01
On the basis of both a conventional relativistic nuclear fluid dynamic model and a two fluid generalization that takes into account the interpenetration of the target and projectile upon contact, collisions between heavy nuclei moving at relativistic speeds are calculated. This is done by solving the relevant equations of motion numerically in three spatial dimensions by use of particle in cell finite difference computing techniques. The effect of incorporating a density isomer, or quasistable state, in the nuclear equation of state at three times normal nuclear density, and the effect of doubling the nuclear compressibility coefficient are studied. For the reaction 20Ne + 238U at a laboratory bombarding energy per nucleon of 393 MeV, the calculated distributions in energy and angle of outgoing charged particles are compared with recent experimental data both integrated over all impact parameters and for nearly central collisions.
Bashinov, Aleksei V; Gonoskov, Arkady A; Kim, A V; Marklund, Mattias; Mourou, G; Sergeev, Aleksandr M
2013-04-30
A comparative analysis is performed of the electron emission characteristics as the electrons move in laser fields with ultra-relativistic intensity and different configurations corresponding to a plane or tightly focused wave. For a plane travelling wave, analytical expressions are derived for the emission characteristics, and it is shown that the angular distribution of the radiation intensity changes qualitatively even when the wave intensity is much less than that in the case of the radiation-dominated regime. An important conclusion is drawn that the electrons in a travelling wave tend to synchronised motion under the radiation reaction force. The characteristic features of the motion of electrons are found in a converging dipole wave, associated with the curvature of the phase front and nonuniformity of the field distribution. The values of the maximum achievable longitudinal momenta of electrons accelerated to the centre, as well as their distribution function are determined. The existence of quasi-periodic trajectories near the focal region of the dipole wave is shown, and the characteristics of the emission of both accelerated and oscillating electrons are analysed. (extreme light fields and their applications)
Gómez, Sergio S; Aucar, Gustavo A
2011-05-28
We present ab inito full four-component and spin-free calculations of the NMR shielding parameter, σ, in the FX (X = F, Cl, Br, I and At) molecular systems. A different expression that overcomes the traditional non-relativistic (NR) approximation used to calculate the relationship between spin-rotation constants and the paramagnetic terms of σ(p) are given. Large deviations from NR results are obtained for σ(X; X = I and At) and for σ(F; FAt). σ(∥)(p)(I; FI) is zero within the NR approach but -447.4 parts per million from our calculations. The electronic origin of relativistic corrections are analyzed. All passive SO contributions are obtained as a difference between full four-component calculations and spin-free ones. Considering relativistic effects on the anisotropy, we obtain a deviation of 10% for I and 25% for At. σ(∥)(SO)(X) is always negative and σ(∥)(SF)(X) is always positive; the passive SO becomes larger than the SF one for X = Br, I, and At. Both σ(∥)(SO)(X) and σ(⊥)(SO)(X) have a functional dependence such as a Z(X)(b) being the exponent 3.5 and 3.65, respectively. The passive SO contribution to the anisotropy has a similar functional dependence with an exponent of 3.60, meaning that its perpendicular component is larger than its corresponding parallel component. PMID:21639447
Relativistic Effects and Polarization in Three High-Energy Pulsar Models
NASA Technical Reports Server (NTRS)
Dyks, J.; Harding, Alice K.; Rudak, B.
2004-01-01
We present the influence of the special relativistic effects of aberration and light travel time delay on pulsar high-energy lightcurves and polarization characteristics predicted by three models: the two-pole caustic model, the outer gap model, and the polar cap model. Position angle curves and degree of polarization are calculated for the models and compared with the optical data on the Crab pulsar. The relative positions of peaks in gamma-ray and radio lightcurves are discussed in detail for the models. We find that the two-pole caustic model can reproduce qualitatively the optical polarization characteristics of the Crab pulsar - fast swings of the position angle and minima in polarization degree associated with both peaks. The anticorrelation between the observed flux and the polarization degree (observed in the optical band also for B0656+14) naturally results from the caustic nature of the peaks which are produced in the model due to the superposition of radiation from many different altitudes, ie. polarized at different angles. The two-pole caustic model also provides an acceptable interpretation of the main features in the Crab's radio profile. Neither the outer gap model nor the polar cap model are able to reproduce the optical polarization data on the Crab. Although the outer gap model is very successful in reproducing the relative positions of gamma-ray and radio peaks in pulse profiles, it can reproduce the high-energy lightcurves only when photon emission from regions very close to the light cylinder is included.
Hafeez-Ur-Rehman; Mahmood, S.; Shah, Asif; Haque, Q.
2011-12-15
Two dimensional (2D) solitons are studied in a plasma system comprising of relativistically streaming ions, kappa distributed electrons, and positrons. Kadomtsev-Petviashvili (KP) equation is derived through the reductive perturbation technique. Analytical solution of the KP equation has been studied numerically and graphically. It is noticed that kappa parameters of electrons and positrons as well as the ions relativistic streaming factor have an emphatic influence on the structural as well as propagation characteristics of two dimensional solitons in the considered plasma system. Our results may be helpful in the understanding of soliton propagation in astrophysical and laboratory plasmas, specifically the interaction of pulsar relativistic wind with supernova ejecta and the transfer of energy to plasma by intense electric field of laser beams producing highly energetic superthermal and relativistic particles [L. Arons, Astrophys. Space Sci. Lib. 357, 373 (2009); P. Blasi and E. Amato, Astrophys. Space Sci. Proc. 2011, 623; and A. Shah and R. Saeed, Plasma Phys. Controlled Fusion 53, 095006 (2011)].
Compression-amplified EMIC waves and their effects on relativistic electrons
NASA Astrophysics Data System (ADS)
Li, L. Y.; Yu, J.; Cao, J. B.; Yuan, Z. G.
2016-06-01
During enhancement of solar wind dynamic pressure, we observe the periodic emissions of electromagnetic ion cyclotron (EMIC) waves near the nightside geosynchronous orbit (6.6RE). In the hydrogen and helium bands, the different polarized EMIC waves have different influences on relativistic electrons (>0.8 MeV). The flux of relativistic electrons is relatively stable if there are only the linearly polarized EMIC waves, but their flux decreases if the left-hand polarized (L-mode) EMIC waves are sufficiently amplified (power spectral density (PSD) ≥ 1 nT2/Hz). The larger-amplitude L-mode waves can cause more electron losses. In contrast, the R-mode EMIC waves are very weak (PSD < 1 nT2/Hz) during the electron flux dropouts; thus, their influence may be ignored here. During the electron flux dropouts, the relativistic electron precipitation is observed by POES satellite near the foot point (˜850 km) of the wave emission region. The quasi-linear simulation of wave-particle interactions indicates that the L-mode EMIC waves can cause the rapid precipitation loss of relativistic electrons, especially when the initial resonant electrons have a butterfly-like pitch angle distribution.
Comment on ``Relativistic effects on the spin entanglement of two massive Dirac particles''
NASA Astrophysics Data System (ADS)
Caban, Paweł; Rembieliński, Jakub
2012-12-01
The paper of Choi [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.84.012334 84, 012334 (2011)] discusses the use of the Foldy-Wouthuysen mean-spin operator in the theory of relativistic quantum information. However, the paper contains some incorrect statements and misunderstandings.
Magnetogenesis through Relativistic Velocity Shear
NASA Astrophysics Data System (ADS)
Miller, Evan
Magnetic fields at all scales are prevalent in our universe. However, current cosmological models predict that initially the universe was bereft of large-scale fields. Standard magnetohydrodynamics (MHD) does not permit magnetogenesis; in the MHD Faraday's law, the change in magnetic field B depends on B itself. Thus if B is initially zero, it will remain zero for all time. A more accurate physical model is needed to explain the origins of the galactic-scale magnetic fields observed today. In this thesis, I explore two velocity-driven mechanisms for magnetogenesis in 2-fluid plasma. The first is a novel kinematic 'battery' arising from convection of vorticity. A coupling between thermal and plasma oscillations, this non-relativistic mechanism can operate in flows that are incompressible, quasi-neutral and barotropic. The second mechanism results from inclusion of thermal effects in relativistic shear flow instabilities. In such flows, parallel perturbations are ubiquitously unstable at small scales, with growth rates of order with the plasma frequency over a defined range of parameter-space. Of these two processes, instabilities seem far more likely to account for galactic magnetic fields. Stable kinematic effects will, at best, be comparable to an ideal Biermann battery, which is suspected to be orders of magnitude too weak to produce the observed galactic fields. On the other hand, instabilities grow until saturation is reached, a topic that has yet to be explored in detail on cosmological scales. In addition to investigating these magnetogenesis sources, I derive a general dispersion relation for three dimensional, warm, two species plasma with discontinuous shear flow. The mathematics of relativistic plasma, sheared-flow instability and the Biermann battery are also discussed.
Waves in general relativistic two-fluid plasma around a Schwarzschild black hole
NASA Astrophysics Data System (ADS)
Rahman, M. Atiqur
2012-10-01
Waves propagating in the relativistic electron-positron or ions plasma are investigated in a frame of two-fluid equations using the 3+1 formalism of general relativity developed by Thorne, Price and Macdonald (TPM). The plasma is assumed to be freefalling in the radial direction toward the event horizon due to the strong gravitational field of a Schwarzschild black hole. The local dispersion relations for transverse and longitudinal waves have been derived, in analogy with the special relativistic formulation as explained in an earlier paper, to take account of relativistic effects due to the event horizon using WKB approximation.
Spin-orbit interaction in relativistic nuclear structure models
NASA Astrophysics Data System (ADS)
Ebran, J.-P.; Mutschler, A.; Khan, E.; Vretenar, D.
2016-08-01
Relativistic self-consistent mean-field (SCMF) models naturally account for the coupling of the nucleon spin to its orbital motion, whereas nonrelativistic SCMF methods necessitate a phenomenological ansatz for the effective spin-orbit potential. Recent experimental studies aim to explore the isospin properties of the effective spin-orbit interaction in nuclei. SCMF models are very useful in the interpretation of the corresponding data; however, standard relativistic mean-field and nonrelativistic Hartree-Fock models use effective spin-orbit potentials with different isovector properties, mainly because exchange contributions are not treated explicitly in the former. The impact of exchange terms on the effective spin-orbit potential in relativistic mean-field models is analyzed, and it is shown that it leads to an isovector structure similar to the one used in standard nonrelativistic Hartree-Fock models. Data on the isospin dependence of spin-orbit splittings in spherical nuclei could be used to constrain the isovector-scalar channel of relativistic mean-field models. The reproduction of the empirical kink in the isotope shifts of even Pb nuclei by relativistic effective interactions points to the occurrence of pseudospin symmetry in the single-neutron spectra in these nuclei.
Relativistic thermal plasmas - Pair processes and equilibria
NASA Technical Reports Server (NTRS)
Lightman, A. P.
1982-01-01
The work of Bisnovatyi-Kogan, Zel'dovich and Sunyaev (1971) is extended and generalized, through the inclusion of pair-producing photon processes and effects due to the finite size of the plasma, in an investigation of the equilibria of relativistic thermal plasmas which takes into account electron-positron creation and annihilation and photons produced within the plasma. It is shown that the bridge between an effectively thin plasma and an effectively thick plasma occurs in the transrelativistic region, where the dimensionless temperature value is between 0.1 and 1.0 and the temperature remains in this region over a great luminosity range.
Mental Accounting in Portfolio Choice: Evidence from a Flypaper Effect.
Choi, James J; Laibson, David; Madrian, Brigitte C
2009-12-01
Consistent with mental accounting, we document that investors sometimes choose the asset allocation for one account without considering the asset allocation of their other accounts. The setting is a firm that changed its 401(k) matching rules. Initially, 401(k) enrollees chose the allocation of their own contributions, but the firm chose the match allocation. These enrollees ignored the match allocation when choosing their own-contribution allocation. In the second regime, enrollees simultaneously selected both accounts' allocations, leading them to mentally integrate the two. Own-contribution allocations before the rule change equal the combined own- and match-contribution allocations afterwards, whereas combined allocations differ sharply across regimes. PMID:20027235
NASA Astrophysics Data System (ADS)
Haba, Z.
2009-02-01
We discuss relativistic diffusion in proper time in the approach of Schay (Ph.D. thesis, Princeton University, Princeton, NJ, 1961) and Dudley [Ark. Mat. 6, 241 (1965)]. We derive (Langevin) stochastic differential equations in various coordinates. We show that in some coordinates the stochastic differential equations become linear. We obtain momentum probability distribution in an explicit form. We discuss a relativistic particle diffusing in an external electromagnetic field. We solve the Langevin equations in the case of parallel electric and magnetic fields. We derive a kinetic equation for the evolution of the probability distribution. We discuss drag terms leading to an equilibrium distribution. The relativistic analog of the Ornstein-Uhlenbeck process is not unique. We show that if the drag comes from a diffusion approximation to the master equation then its form is strongly restricted. The drag leading to the Tsallis equilibrium distribution satisfies this restriction whereas the one of the Jüttner distribution does not. We show that any function of the relativistic energy can be the equilibrium distribution for a particle in a static electric field. A preliminary study of the time evolution with friction is presented. It is shown that the problem is equivalent to quantum mechanics of a particle moving on a hyperboloid with a potential determined by the drag. A relation to diffusions appearing in heavy ion collisions is briefly discussed.
Haba, Z
2009-02-01
We discuss relativistic diffusion in proper time in the approach of Schay (Ph.D. thesis, Princeton University, Princeton, NJ, 1961) and Dudley [Ark. Mat. 6, 241 (1965)]. We derive (Langevin) stochastic differential equations in various coordinates. We show that in some coordinates the stochastic differential equations become linear. We obtain momentum probability distribution in an explicit form. We discuss a relativistic particle diffusing in an external electromagnetic field. We solve the Langevin equations in the case of parallel electric and magnetic fields. We derive a kinetic equation for the evolution of the probability distribution. We discuss drag terms leading to an equilibrium distribution. The relativistic analog of the Ornstein-Uhlenbeck process is not unique. We show that if the drag comes from a diffusion approximation to the master equation then its form is strongly restricted. The drag leading to the Tsallis equilibrium distribution satisfies this restriction whereas the one of the Jüttner distribution does not. We show that any function of the relativistic energy can be the equilibrium distribution for a particle in a static electric field. A preliminary study of the time evolution with friction is presented. It is shown that the problem is equivalent to quantum mechanics of a particle moving on a hyperboloid with a potential determined by the drag. A relation to diffusions appearing in heavy ion collisions is briefly discussed. PMID:19391727
Unstable particles in non-relativistic quantum mechanics?
Hernandez-Coronado, H.
2011-10-14
The Schroedinger equation is up-to-a-phase invariant under the Galilei group. This phase leads to the Bargmann's superselection rule, which forbids the existence of the superposition of states with different mass and implies that unstable particles cannot be described consistently in non-relativistic quantum mechanics (NRQM). In this paper we claim that Bargmann's rule neglects physical effects and that a proper description of non-relativistic quantum mechanics requires to take into account this phase through the Extended Galilei group and the definition of its action on spacetime coordinates.
Crystallization and collapse in relativistically degenerate matter
Akbari-Moghanjoughi, M.
2013-04-15
In this paper, it is shown that a mass density limit exists beyond which the relativistically degenerate matter would crystallize. The mass density limit, found here, is quite analogous to the mass limit predicted by Chandrasekhar for a type of compact stars called white dwarfs (M{sub Ch} Asymptotically-Equal-To 1.43 Solar Mass). In this study, the old problem of white dwarf core collapse, which has been previously investigated by Chandrasekhar using hydrostatic stability criteria, is revisited in the framework of the quantum hydrodynamics model by inspection of the charge screening at atomic scales in the relativistic degeneracy plasma regime taking into account the relativistic Fermi-Dirac statistics and electron interaction features such as the quantum statistical pressure, Coulomb attraction, electron exchange-correlation, and quantum recoil effects. It is revealed that the existence of ion correlation and crystallization of matter in the relativistically degenerate plasma puts a critical mass density limit on white dwarf core region. It is shown that a white dwarf star with a core mass density beyond this critical limit can undergo the spontaneous core collapse (SCC). The SCC phenomenon, which is dominantly caused by the electron quantum recoil effect (interference and localization of the electron wave function), leads to a new exotic state of matter. In such exotic state, the relativistic electron degeneracy can lead the white dwarf crystallized core to undergo the nuclear fusion and an ultimate supernova by means of the volume reduction (due to the enhanced compressibility) and huge energy release (due to the increase in cohesive energy), under the stars huge inward gravitational pressure. Moreover, it is found that the SCC phenomenon is significantly affected by the core composition (it is more probable for heavier plasmas). The critical mass density found here is consistent with the values calculated for core density of typical white dwarf stars.
Nuclear Material Control and Accountability System Effectiveness Tool (MSET)
Powell, Danny H; Elwood Jr, Robert H; Roche, Charles T; Campbell, Billy J; Hammond, Glenn A; Meppen, Bruce W; Brown, Richard F
2011-01-01
A nuclear material control and accountability (MC&A) system effectiveness tool (MSET) has been developed in the United States for use in evaluating material protection, control, and accountability (MPC&A) systems in nuclear facilities. The project was commissioned by the National Nuclear Security Administration's Office of International Material Protection and Cooperation. MSET was developed by personnel with experience spanning more than six decades in both the U.S. and international nuclear programs and with experience in probabilistic risk assessment (PRA) in the nuclear power industry. MSET offers significant potential benefits for improving nuclear safeguards and security in any nation with a nuclear program. MSET provides a design basis for developing an MC&A system at a nuclear facility that functions to protect against insider theft or diversion of nuclear materials. MSET analyzes the system and identifies several risk importance factors that show where sustainability is essential for optimal performance and where performance degradation has the greatest impact on total system risk. MSET contains five major components: (1) A functional model that shows how to design, build, implement, and operate a robust nuclear MC&A system (2) A fault tree of the operating MC&A system that adapts PRA methodology to analyze system effectiveness and give a relative risk of failure assessment of the system (3) A questionnaire used to document the facility's current MPC&A system (provides data to evaluate the quality of the system and the level of performance of each basic task performed throughout the material balance area [MBA]) (4) A formal process of applying expert judgment to convert the facility questionnaire data into numeric values representing the performance level of each basic event for use in the fault tree risk assessment calculations (5) PRA software that performs the fault tree risk assessment calculations and produces risk importance factor reports on the
Integrating Effective Writing Skills in the Accounting Curriculum.
ERIC Educational Resources Information Center
May, Gordon S.; Arevalo, Claire
1983-01-01
The J. M. Tull School of Accounting at the University of Georgia has developed a program that integrates the teaching of writing skills with the regular accounting courses. Students in a three-course sequence write a total of eight papers--technical, memos, or reports--in assignments that resemble writing tasks encountered by professional…
Stanke, Monika; Adamowicz, Ludwik
2013-10-01
In this work, we describe how the energies obtained in molecular calculations performed without assuming the Born-Oppenheimer (BO) approximation can be augmented with corrections accounting for the leading relativistic effects. Unlike the conventional BO approach, where these effects only concern the relativistic interactions between the electrons, the non-BO approach also accounts for the relativistic effects due to the nuclei and due to the coupling of the coupled electron-nucleus motion. In the numerical sections, the results obtained with the two approaches are compared. The first comparison concerns the dissociation energies of the two-electron isotopologues of the H2 molecule, H2, HD, D2, T2, and the HeH(+) ion. The comparison shows that, as expected, the differences in the relativistic contributions obtained with the two approaches increase as the nuclei become lighter. The second comparison concerns the relativistic corrections to all 23 pure vibrational states of the HD(+) ion. An interesting charge asymmetry caused by the nonadiabatic electron-nucleus interaction appears in this system, and this effect significantly increases with the vibration excitation. The comparison of the non-BO results with the results obtained with the conventional BO approach, which in the lowest order does not describe the charge-asymmetry effect, reveals how this effect affects the values of the relativistic corrections. PMID:23679131
Highly Relativistic Electrons from UARS and Their Effect on Atmospheric Ozone
NASA Astrophysics Data System (ADS)
Pesnell, W. D.; Goldberg, R. A.; Jackman, C. H.; Chenette, D. L.; Gaines, E. E.
2001-12-01
In a study involving 5 of the instruments on UARS, we have investigated how fluxes of high-energy electrons could modify the chemistry of the upper stratosphere and mesosphere. Fluxes of high-energy electrons (E > 100~keV) have been predicted to deplete mesospheric ozone by 20% or more, and stratospheric ozone to a lesser degree. Precipitating fluxes of these electrons can increase by 1--2 orders of magnitude during highly relativistic electron (HRE) events, and often contain significant contributions from electrons with E > 1~MeV. This research has produced a database of differential electron energy spectra obtained during the decline of solar cycle 22. We have used this database to understand the radiation environment of low-Earth orbit. We will show how the HEPS data provides energy-dependent lifetimes for the energetic electrons and that elevated electron fluxes should be expected on any satellite mission lasting more than 1 week. Once the electron fluxes are known, the atmospheric effects can be predicted by model calculations and those predictions compared with composition measurements. For the instantaneous electron fluxes measured during a large May 1992 HRE, relative depletions of ozone greater than 15% were predicted to occur between altitudes of 60--80~km, where HO{}x reactions cause a local minimum in the ozone concentration. The chemical signature of an HRE would be ozone depletions in the region of enhanced flux, particularly within the magnetic L-shell limits of 3 < L < 4. Data from HEPS, CLAES, HALOE, HRDI, and MLS were combined to search for such effects during the May 1992 HRE. Mesospheric ozone measurements from HRDI and stratospheric ozone measurements by CLAES and MLS were searched for the predicted depletions. The seasonal evolution of water vapor was monitored with HALOE. Our analysis shows that between altitudes of 65--75 km the ozone mixing ratio was relatively constant within the overlapping local solar time bands during May 1992. Above 80
Mental Accounting in Portfolio Choice: Evidence from a Flypaper Effect
Choi, James J.; Laibson, David; Madrian, Brigitte C.
2009-01-01
Consistent with mental accounting, we document that investors sometimes choose the asset allocation for one account without considering the asset allocation of their other accounts. The setting is a firm that changed its 401(k) matching rules. Initially, 401(k) enrollees chose the allocation of their own contributions, but the firm chose the match allocation. These enrollees ignored the match allocation when choosing their own-contribution allocation. In the second regime, enrollees simultaneously selected both accounts’ allocations, leading them to mentally integrate the two. Own-contribution allocations before the rule change equal the combined own- and match-contribution allocations afterwards, whereas combined allocations differ sharply across regimes. PMID:20027235
Pseudo-Newtonian models for the equilibrium structures of rotating relativistic stars
NASA Astrophysics Data System (ADS)
Kim, Jinho; Il Kim, Hee; Mok Lee, Hyung
2009-10-01
We obtain equilibrium solutions for rotating compact stars, including special relativistic effects. The gravity is assumed to be Newtonian, but we use the active mass density, which takes into account all energies such as the motion of the fluid, internal energy and pressure energy in addition to the rest-mass energy, in computing the gravitational potential using Poisson's equation. Such a treatment could be applicable to neutron stars with relativistic motions or a relativistic equation of state. We applied Hachisu's self-consistent field (SCF) method to find spheroidal as well as toroidal sequences of equilibrium solutions. Our solutions show better agreement with general relativistic solutions than the Newtonian relativistic hydrodynamic approach, which does not take into account the active mass. Physical quantities such as the peak density and equatorial radii in our solutions agree with the general relativistic ones to within 5 per cent. Therefore our approach can be used as a simple alternative to the fully relativistic one when a large number of model calculations is necessary, as it requires much fewer computational resources.
Communication: Determination of relativistic effects from X-ray structure factors
NASA Astrophysics Data System (ADS)
Batke, Kilian; Eickerling, Georg
2016-02-01
In this communication, a procedure is presented which allows for the determination of the scalar-relativistic contraction of individual electronic shells of transition metal atoms from X-ray structure factor data. The procedure is verified and benchmarked employing theoretical and experimental F(hkl) data, revealing an overall good agreement between the experimentally determined results and the theoretical reference values. From the experimental data, the relativistic contraction of the n = 2 shell of a cerium atom is, for example, determined as 0.097 pm, compared to a theoretical reference value of 0.116 pm. It is further demonstrated that the reproducibility of the results is excellent when comparing different experimental data sets. Finally, the dependency of the according results on the data resolution of the structure factor data is investigated.
Gusakov, Mikhail E.; Kantor, Elena M.; Haensel, Pawel
2009-07-15
We calculate the important quantity of superfluid hydrodynamics, the relativistic entrainment matrix for a nucleon-hyperon mixture at arbitrary temperature. In the nonrelativistic limit this matrix is also termed the Andreev-Bashkin or mass-density matrix. Our results can be useful for modeling the pulsations of massive neutron stars with superfluid nucleon-hyperon cores and for studies of the kinetic properties of superfluid baryon matter.