R. Herrmann
2013-09-20
In cluster physics a single particle potential to determine the microscopic part of the total energy of a collective configuration is necessary to calculate the shell- and pairing effects. In this paper we investigate the properties of the Riesz fractional integrals and compare their properties with the standard Coulomb and Yukawa potentials commonly used. It is demonstrated, that Riesz potentials may serve as a promising extension of standard potentials and may be reckoned as a smooth transition from Coulomb to Yukawa like potentials, depending of the fractional parameter $\\alpha$. For the macroscopic part of the total energy the Riesz potentials treat the Coulomb-, symmetry- and pairing-contributions from a generalized point of view, since they turn out to be similar realizations of the same fractional integral at distinct $\\alpha$ values.
NASA Astrophysics Data System (ADS)
Ikot, Akpan N.; Hassanabadi, Hassan; Obong, Hillary Patrick; Mehraban, H.; Yazarloo, Bentol Hoda
2015-07-01
The effects of Coulomb-like tensor (CLT), Yukawa-like tensor (YLT) and generalized tensor (GLT) interactions are investigated in the Dirac theory with Schiöberg and Manning-Rosen potentials within the framework of spin and pseudospin symmetries using the Nikiforov-Uvarov method. The bound state energy spectra and the radial wave functions have been approximately obtained in the case of spin and pseudospin symmetries. We have also reported some numerical results and figures to show the effects these tensor interactions.
NASA Astrophysics Data System (ADS)
Ho, Y. K.; Kar, S.
2012-10-01
The doubly-excited inter-shell resonance states of the hydrogen negative ion with screened Coulomb potentials are investigated in the framework of complex-scaling method. Highly correlated wave functions with terms up to 1078 in Hylleraas coordinates are used. The resonance parameters for the 2 s3 s 1 S e associated with the H ( N = 2) threshold and the 3 s4 s 1 S e state associated with the H ( N = 3) threshold for various screening strengths are reported. Comparisons are made with other available data in the literature.
YUKAWA POTENTIAL, PANHARMONIC MEASURE AND BROWNIAN MOTION
Sottinen, Tommi
. The equation (1.1) first arose from the work of the Japanese physicist Hideki Yukawa in particle physics. HereYUKAWA POTENTIAL, PANHARMONIC MEASURE AND BROWNIAN MOTION ANTTI RASILA AND TOMMI SOTTINEN Abstract. The panharmonic measure is a generalization of the har- monic measure for the solutions of the Yukawa partial
Lorentz Violation and the Yukawa Potential
B. Altschul
2006-05-03
We analyze Lorentz violations in the bosonic sector of a Yukawa-type quantum field theory. The nonrelativistic potential may be determined to all orders in the Lorentz violation, and we find that only specific types of modifications to the normal Yukawa potential can be generated. The influence of this modified potential on scattering and bounds states is calculated. These results could be relevant to the search for new macroscopic forces, which may not necessarily be Lorentz invariant.
Using the Screened Coulomb Potential to Illustrate the Variational Method
ERIC Educational Resources Information Center
Zuniga, Jose; Bastida, Adolfo; Requena, Alberto
2012-01-01
The screened Coulomb potential, or Yukawa potential, is used to illustrate the application of the single and linear variational methods. The trial variational functions are expressed in terms of Slater-type functions, for which the integrals needed to carry out the variational calculations are easily evaluated in closed form. The variational…
Yukawa particles in a confining potential
Girotto, Matheus Levin, Yan; Santos, Alexandre P. dos; Colla, Thiago
2014-07-07
We study the density distribution of repulsive Yukawa particles confined by an external potential. In the weak coupling limit, we show that the mean-field theory is able to accurately account for the particle distribution. In the strong coupling limit, the correlations between the particles become important and the mean-field theory fails. For strongly correlated systems, we construct a density functional theory which provides an excellent description of the particle distribution, without any adjustable parameters.
An Alternative Treatment for Yukawa-Type Potentials
B. Gonul; K. Koksal; E. Bakir
2005-07-11
We propose a new approximation scheme to obtain analytic expressions for the bound state energies and eigenfunctions of Yukawa like potentials. The predicted energies are in excellent agreement with the accurate numerical values reported in the literature.
An Alternative Treatment for Yukawa-Type Potentials
Gönül, B; Bakir, E
2005-01-01
We propose a new approximation scheme to obtain analytic expressions for the bound state energies and eigenfunctions of Yukawa like potentials. The predicted energies are in excellent agreement with the accurate numerical values reported in the literature.
Revision of FMM-Yukawa: An adaptive fast multipole method for screened Coulomb interactions
NASA Astrophysics Data System (ADS)
Zhang, Bo; Huang, Jingfang; Pitsianis, Nikos P.; Sun, Xiaobai
2010-12-01
FMM-YUKAWA is a mathematical software package primarily for rapid evaluation of the screened Coulomb interactions of N particles in three dimensional space. Since its release, we have revised and re-organized the data structure, software architecture, and user interface, for the purpose of enabling more flexible, broader and easier use of the package. The package and its documentation are available at http://www.fastmultipole.org/, along with a few other closely related mathematical software packages. New version program summaryProgram title: FMM-Yukawa Catalogue identifier: AEEQ_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEQ_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL 2.0 No. of lines in distributed program, including test data, etc.: 78 704 No. of bytes in distributed program, including test data, etc.: 854 265 Distribution format: tar.gz Programming language: FORTRAN 77, FORTRAN 90, and C. Requires gcc and gfortran version 4.4.3 or later Computer: All Operating system: Any Classification: 4.8, 4.12 Catalogue identifier of previous version: AEEQ_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 2331 Does the new version supersede the previous version?: Yes Nature of problem: To evaluate the screened Coulomb potential and force field of N charged particles, and to evaluate a convolution type integral where the Green's function is the fundamental solution of the modified Helmholtz equation. Solution method: The new version of fast multipole method (FMM) that diagonalizes the multipole-to-local translation operator is applied with the tree structure adaptive to sample particle locations. Reasons for new version: To handle much larger particle ensembles, to enable the iterative use of the subroutines in a solver, and to remove potential contention in assignments for parallelization. Summary of revisions: The software package FMM-Yukawa has been revised and re-organized in data structure, software architecture, programming methods, and user interface. The revision enables more flexible use of the package and economic use of memory resources. It consists of five stages. The initial stage (stage 1) determines, based on the accuracy requirement and FMM theory, the length of multipole expansions and the number of quadrature points for diagonalization, and loads the quadrature nodes and weights that are computed off line. Stage 2 constructs the oct-tree and interaction lists, with adaptation to the sparsity or density of particles and employing a dynamic memory allocation scheme at every tree level. Stage 3 executes the core FMM subroutine for numerical calculation of the particle interactions. The subroutine can now be used iteratively as in a solver, while the particle locations remain the same. Stage 4 releases the memory allocated in Stage 2 for the adaptive tree and interaction lists. The user can modify the iterative routine easily. When the particle locations are changed such as in a molecular dynamics simulation, stage 2 to 4 can also be used together repeatedly. The final stage releases the memory space used for the quadrature and other remaining FMM parameters. Programs at the stage level and at the user interface are re-written in the C programming language, while most of the translation and interaction operations remain in FORTRAN. As a result of the change in data structures and memory allocation, the revised package can accommodate much larger particle ensembles while maintaining the same accuracy-efficiency performance. The new version is also developed as an important precursor to its parallel counterpart on multi-core or many core processors in a shared memory programming environment. Particularly, in order to ensure mutual exclusion in concurrent updates without incurring extra latency, we have replaced all the assignment statements at a source box that put its data to multiple target boxes with assignments at every target box that gather data from source boxes. This amounts to replacing t
Stationary solution of NLFP with coulombic potential
Grassi, A.
2013-02-15
In a previous paper, Grassi (2012) [39], a new entropy form has been proposed for which it is possible to obtain a stationary solution of the Non-Linear Fokker-Planck equation (referred as NLFP) with coulombic-like potentials. In this paper we analyze the stationary solution of NLFP obtained by using pure coulombic potentials and we will use this solution to study an 'atomic-like' system. - Highlights: Black-Right-Pointing-Pointer The entropy introduced in a previous work has been studied for a coulombic potential. Black-Right-Pointing-Pointer From this entropy form a NLFP has been derived for a pure coulombic potential. Black-Right-Pointing-Pointer The stationary solution of the NLFP for an 'atomic-like' system has been obtained. Black-Right-Pointing-Pointer A comparison with Boltzmann entropy has been proposed.
Accurate momentum transfer cross section for the attractive Yukawa potential
Khrapak, S. A.
2014-04-15
Accurate expression for the momentum transfer cross section for the attractive Yukawa potential is proposed. This simple analytic expression agrees with the numerical results better than to within ±2% in the regime relevant for ion-particle collisions in complex (dusty) plasmas.
The Coulombic Lattice Potential of Ionic Compounds: The Cubic Perovskites.
ERIC Educational Resources Information Center
Francisco, E.; And Others
1988-01-01
Presents coulombic models representing the particles of a system by point charges interacting through Coulomb's law to explain coulombic lattice potential. Uses rubidium manganese trifluoride as an example of cubic perovskite structure. Discusses the effects on cluster properties. (CW)
Compact Lattice QED and the Coulomb Potential
Y. N. Srivstava; A. Widom; M. H. Friedman; O. Panella
1992-09-01
The potential energy of a static charge distribution on a lattice is rigorously computed in the standard compact quantum electrodynamic model. The method used follows closely that of Weyl for ordinary quantum electrodynamics in continuous space-time. The potential energy of the static charge distribution is independent of temperature and can be calculated from the lattice version of Poisson's equation. It is the usual Coulomb potential.
Melting of small clusters with Yukawa interaction potential
NASA Astrophysics Data System (ADS)
Koss, X. G.; Petrov, O. F.; Myasnikov, M. I.; Statsenko, K. B.; Vasiliev, M. M.
2015-11-01
In present work, the results of the numerical simulation of the dynamics of twodimensional clusters of 7 and 18 particles interacting via the Yukawa potential are presented. The simulation was carried out by the Langevin molecular dynamics method. We have numerically obtained the MFPT entropy functions for the systems of 7 and 18 particles for the various values of kinetic temperature, corresponding to the conditions of the laboratory experiments with gas-discharge dusty plasma. Three phase states of the considered small systems are registered: crystal, liquid and transitional. The mechanism of phase transitions in the systems under study is described. The suggested technique of the analysis of the system dynamics can be applied to the structures as small as desired.
Positron scattering from hydrogen atom with screened Coulomb potentials
Ghoshal, Arijit; Nayek, Sujay; Kamali, M. Z. M.; Ratnavelu, K.
2014-03-05
Elastic positron-hydrogen collisions with screened Coulomb potentials have been investigated using a second-order distorted wave Born approximation in the momentum space. Two types of potentials have been considered, namely, static screened Coulomb potential and exponential cosine-screened Coulomb potential. Using a simple variationally determined hydrogenic wave function it has been possible to obtain the scattering amplitude in a closed form. A detailed study has been made on the differential and total cross sections in the energy range 20–300 eV.
TESTING YUKAWA-LIKE POTENTIALS FROM f(R)-GRAVITY IN ELLIPTICAL GALAXIES
Napolitano, N. R.; Capozziello, S.; Capaccioli, M.; Romanowsky, A. J.
2012-04-01
We present the first analysis of extended stellar kinematics of elliptical galaxies where a Yukawa-like correction to the Newtonian gravitational potential derived from f(R)-gravity is considered as an alternative to dark matter. In this framework, we model long-slit data and planetary nebula data out to 7 R{sub eff} of three galaxies with either decreasing or flat dispersion profiles. We use the corrected Newtonian potential in a dispersion-kurtosis Jeans analysis to account for the mass-anisotropy degeneracy. We find that these modified potentials are able to fit nicely all three elliptical galaxies and the anisotropy distribution is consistent with that estimated if a dark halo is considered. The parameter which measures the 'strength' of the Yukawa-like correction is, on average, smaller than the one found previously in spiral galaxies and correlates both with the scale length of the Yukawa-like term and the orbital anisotropy.
Analytical approximation for the sphere-sphere Coulomb potential
R. Anni
2001-02-22
A simple analytical expression, which closely approximates the Coulomb potential between two uniformly charged spheres, is presented. This expression can be used in the optical potential semiclassical analyses which require that the interaction be analytic on and near the real r-axis.
Electron screening of the Coulomb potential at small internuclear distances
NASA Astrophysics Data System (ADS)
Zinoviev, A. N.
2015-07-01
Values of He+-Au potential at small internuclear distances (R = 10-4 to 10-3 nm) have been obtained from the Rutherford backscattering (RBS) data. The potential has been shown to be independent of the collision velocity and close to the potential approximation proposed in Zinoviev (2011) [1]. Experimental data on the electron screening of the Coulomb potential enabled calculation of corrections for the nuclear fusion cross-sections and improvement of the RBS data quantitative analysis.
Spectral sum for the color-Coulomb potential in SU(3) Coulomb gauge lattice Yang-Mills theory
Nakagawa, Y.; Nakamura, A.; Saito, T.; Toki, H.
2010-03-01
We discuss the essential role of the low-lying eigenmodes of the Faddeev-Popov (FP) ghost operator on the confining color-Coulomb potential using SU(3) quenched lattice simulations in the Coulomb gauge. The color-Coulomb potential is expressed as a spectral sum of the FP ghost operator and has been explored by partially summing the FP eigenmodes. We take into account the Gribov copy effects that have a great impact on the FP eigenvalues and the color-Coulomb potential. We observe that the lowest eigenvalue vanishes in the thermodynamic limit much faster than that in the Landau gauge. The color-Coulomb potential at large distances is governed by the near-zero FP eigenmodes; in particular, the lowest one accounts for a substantial portion of the color-Coulomb string tension comparable to the Wilson string tension.
Macroscopic Screening of Coulomb Potentials From UV/IR-Mixing
Robert C. Helling; Jiangyang You
2008-02-08
We compute the static potential in a non-commutative theory including a term due to UV/IR-mixing. As a result, the potential decays exponentially fast with distance rather than like a power law Coulomb type potential due to the exchange of massless particles. This shows that when quantum effects are taken into account the introduction of non-commutativity not only modifies physics at short distances but has dramatic macroscopic consequences as well. As a result, we give a lower bound on the scale of non-commutativity (if present at all) to be compatible with observations.
{alpha}-particle optical potential tests below the Coulomb barrier
Avrigeanu, M.; Avrigeanu, V.
2009-02-15
The results of two recent papers concerning ({alpha},{gamma}) and ({alpha},n) reaction cross sections close to the reaction thresholds are discussed with regard to predictions of a recent {alpha}-particle regional optical potential. It is found that the new measured cross sections are rather well described especially for the dominant reaction channels. Particular features of the {alpha}-particle optical potential at energies below the Coulomb barrier explain the failure of a former regional potential obtained by analysis of {alpha}-particle elastic scattering alone at higher energies. Additional limitations of statistical model calculations for minor reaction channels are also discussed.
Gazzillo, Domenico
2011-03-28
For fluids of molecules with short-ranged hard-sphere-Yukawa (HSY) interactions, it is proven that the Noro-Frenkel "extended law of corresponding states" cannot be applied down to the vanishing attraction range, since the exact HSY second virial coefficient diverges in such a limit. It is also shown that, besides Baxter's original approach, a fully correct alternative definition of "adhesive hard spheres" can be obtained by taking the vanishing-range-limit (sticky limit) not of a Yukawa tail, as is commonly done, but of a slightly different potential with a logarithmic-Yukawa attraction. PMID:21456673
Shear Viscosity of Two-Dimensional Yukawa Systems in the Liquid State Bin Liu and J. Goree
Goree, John
Shear Viscosity of Two-Dimensional Yukawa Systems in the Liquid State Bin Liu and J. Goree 2005; published 11 May 2005) The shear viscosity of a two-dimensional (2D) liquid was calculated using molecular dynamics simulations with a Yukawa potential. The viscosity has a minimum at a Coulomb coupling
Serber symmetry, large N{sub c}, and Yukawa-like one-boson exchange potentials
Calle Cordon, A.; Arriola, E. Ruiz
2009-07-15
The Serber force has relative orbital parity symmetry and requires vanishing NN interactions in partial waves with odd angular momentum. We illustrate how this property is well fulfilled for spin triplet states with odd angular momentum and violated for odd singlet states for realistic potentials but fails for chiral potentials. The analysis is carried out in terms of partial wave sum rules for NN phase shifts, r-space potentials at long distances, and V{sub lowk} potentials. We analyze how Serber symmetry can be accommodated within a large-N{sub c} perspective when interpreted as a long-distance symmetry. A prerequisite for this is the numerical similarity of the scalar and vector meson resonance masses. The conditions under which the resonance exchange potential can be approximated by a Yukawa form are also discussed. Although these masses arise as poles on the second Riemann in {pi}{pi} scattering, we find that within the large-N{sub c} expansion the corresponding Yukawa masses correspond instead to a well-defined large-N{sub c} approximation to the pole that cannot be distinguished from their location as Breit-Wigner resonances.
Cores in dwarf galaxies from dark matter with a Yukawa potential.
Loeb, Abraham; Weiner, Neal
2011-04-29
We show that cold dark matter particles interacting through a Yukawa potential could naturally explain the recently observed cores in dwarf galaxies without affecting the dynamics of objects with a much larger velocity dispersion, such as clusters of galaxies. The velocity dependence of the associated cross section as well as the possible exothermic nature of the interaction alleviates earlier concerns about strongly interacting dark matter. Dark matter evaporation in low-mass objects might explain the observed deficit of satellite galaxies in the Milky Way halo and have important implications for the first galaxies and reionization. PMID:21635025
S. L. Yakovlev; V. A. Gradusov
2012-06-25
The zero range potential is constructed for a system of two particles interacting via the Coulomb potential. The singular part of the asymptote of the wave function at the origin which is caused by the common effect of the zero range potential singularity and of the Coulomb potential is explicitly calculated by using the Lippmann-Schwinger type integral equation. The singular pseudo potential is constructed from the requirement that it enforces the solution to the Coulomb Schr\\"odinger equation to possess the calculated asymptotic behavior at the origin. This pseudo potential is then used for constructing a model of the imaginary absorbing potential which allows to treat the annihilation process in positron electron collisions on the basis of the non relativistic Schr\\"odinger equation. The functional form of the pseudo potential constructed in this paper is analogous to the well known Fermi-Breit-Huang pseudo potential. The generalization of the optical theorem on the case of the imaginary absorbing potential in presence of the Coulomb force is given in terms of the partial wave series.
Regularization of the second-order partial derivatives of the Coulomb potential of a point charge
V. Hnizdo
2006-03-07
The second-order partial derivatives of the Coulomb potential of a point charge can be regularized using the Coulomb potential of a charge of the oblate spheroidal shape that a moving rest-frame-spherical charge acquires by the Lorentz contraction. This `physical' regularization is shown to be fully equivalent to the standard delta-function identity involving these derivatives.
Screened Coulomb potentials for astrophysical nuclear fusion reactions
Theodore E. Liolios
2000-09-04
The electron-screening acceleration of laboratory fusion reactions at astrophysical energies is an unsolved problem of great importance to astrophysics. That effect is modeled here by considering the fusion of hydrogen-like atoms whose electron probability density is used in Poisson's equation in order to derive the corresponding screened Coulomb potential energy. That way atomic excitations and deformations of the fusing atoms can be taken into account. Those potentials are then treated semiclassically in order to obtain the screening (accelerating) factor of the reaction. By means of the proposed model the effect of a superstrong magnetic field on laboratory Hydrogen fusion reactions is investigated here for the first time showing that, despite the considerable increase in the cross section of the $% dd$ reaction, the $pp$ reaction is still too slow to justify experimentation. The proposed model is finally applied on the $H^{2}(d,p) H^{3}$ fusion reaction describing satisfactorily the experimental data although some ambiguity remains regarding the molecular nature of the deuteron target. Notably, the present method gives a sufficiently high screening energy for Hydrogen fusion reactions so that the take-away energy of the spectator nucleus can also be taken into account.
Three-potential formalism for the three-body Coulomb scattering problem
Z. Papp
1997-01-16
We propose a three-potential formalism for the three-body Coulomb scattering problem. The corresponding integral equations are mathematically well-behaved and can succesfully be solved by the Coulomb-Sturmian separable expansion method. The results show perfect agreements with existing low-energy $n-d$ and $p-d$ scattering calculations.
Propagation of gravitational waves from slow motion sources in a Coulomb type potential
Asada, H; Asada, Hideki; Futamase, Toshifumi
1997-01-01
We consider the propagation of gravitational waves generated by slow motion sources in Coulomb type potential due to the mass of the source. Then, the formula for gravitational waveform including tail is obtained in a straightforward manner by using the spherical Coulomb function. We discuss its relation with the formula in the previous work.
Crystallization limits of the two-term Yukawa potentials based on the entropy criterion
NASA Astrophysics Data System (ADS)
Lee, Lloyd L.; Hara, Michael C.; Simon, Steven J.; Ramos, Franklin S.; Winkle, Andrew J.; Bomont, Jean-Marc
2010-02-01
We examine the fluid-solid transition for the potential with two Yukawa terms (one attractive and the other repulsive) and a hard core by exploration of the parameter space of (K1, Z1, and Z2), i.e., the parameters of interaction strength and interaction ranges, respectively. We apply the single-phase crystallization rule of Giaquinta and Giunta (1992) by searching for the conditions where the residual entropy reaches zero. To obtain accurate entropy properties, we adopt the self-consistent closure theory of the zero-separation genre. This closure gives accurate thermodynamic properties. The Ornstein-Zernike equation is solved to obtain the correlation functions. The structure factor S(q ) is examined with respect to its cluster-cluster peak, whose value is another indication of phase transition according to Hansen and Verlet (1969). We discover that the parameter Z1 (which determines the range of attractive forces) is important in crystal formation, so long as sufficient attraction (parameter K1) is present. If the range of attraction is too narrow, strength alone is not adequate to satisfy the Giaquinta rule or to solidify at given concentration and temperature. The control of the range of repulsion rests with the Z2-parameter. Its variations can bring about a high peak in S(q ) at zero wave number (i.e., at q =0). Implications for the crystallization of protein and colloidal solutions are discussed.
NASA Astrophysics Data System (ADS)
Ikot, Akpan N.; Maghsoodi, Elham; Hassanabadi, Hassan; Obu, Joseph A.
2014-05-01
In this paper, we obtain the approximate analytical bound-state solutions of the Dirac particle with the generalized Yukawa potential within the framework of spin and pseudospin symmetries for the arbitrary ? state with a generalized tensor interaction. The generalized parametric Nikiforov-Uvarov method is used to obtain the energy eigenvalues and the corresponding wave functions in closed form. We also report some numerical results and present figures to show the effect of the tensor interaction.
Deflections of photoelectron classical trajectories in screened Coulomb potentials of H2+
NASA Astrophysics Data System (ADS)
Qin, Bo-Ya; Wang, Pei-Jie; He, Feng
2015-11-01
The photoelectron momentum distribution of in circularly polarized laser fields is studied based on classical trajectory calculations. We screen Coulomb potentials at different radii, and trace trajectories of an ensemble of electrons in such screened Coulomb potentials and circularly polarized laser fields. Simulations show that electron trajectories are bent by Coulomb fields, resulting in the laser-intensity-dependent drift of photoelectron momentum distributions in the laser polarization plane. This study intuitively explains how Coulomb potentials modify photoelectron momenta. Project supported by the National Natural Science Foundation of China (Grant Nos. 11104180, 11175120, 11121504, and 11322438) and the Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China (Grant No. 131010).
Nasrin. Salehi; Mahsa. Ghazvini
2015-04-28
In this paper, the binding energy of Lithium nucleus in a nonrelativistic model is obtained for the Hulth\\'en and the Inversely Quadratic Yukawa Potential. In order to that, we used the concept of supersymmetry to solving the Schr\\"odinger equation exact analytically. These potentials, due to their physical interpretations, are of interest within many areas of theoretical physics. The results of our model for all calculations show that the ground state binding energy of Lithium nucleus with these potentials are very close to the ones obtained in experiments.
Symmetrization of the Coulomb pairing potential by electron-phonon interaction
Belyavsky, V. I. Kapaev, V. V.; Kopaev, Yu. V.; Mikhailyan, D. I.
2012-08-15
It is shown that the Coulomb superconducting pairing in systems with the Fermi contour nesting can be described by a quasi-one-dimensional potential oscillating in real space. The supplement of this repulsive potential with an isotropic pairing attraction corresponding to the phonon superconductivity mechanism and including the effect of predominant forward scattering upon electron-phonon interaction leads to symmetrization of this potential and a considerable increase in the superconducting transition temperature.
Unified treatment of screening Coulomb and anharmonic oscillator potentials in arbitrary dimensions
Bulent Gonul; Okan Ozer; Mehmet Kocak
2004-03-29
A mapping is obtained relating radial screened Coulomb systems with low screening parameters to radial anharmonic oscillators in N-dimensional space. Using the formalism of supersymmetric quantum mechanics, it is shown that exact solutions of these potentials exist when the parameters satisfy certain constraints.
The algebra of the quantum nondegenerate three-dimensional Kepler-Coulomb potential
Tanoudis, Y.; Daskaloyannis, C.
2011-07-15
The classical generalized Kepler-Coulomb potential, introduced by Verrier and Evans, corresponds to a quantum superintegrable system, with quadratic and quartic integrals of motion. In this paper we show that the algebra of the integrals is a quadratic ternary algebra, i.e a quadratic extension of a Lie triple system.
Numerical treatment of the long-range Coulomb potential with Berggren bases
Michel, N.
2011-03-15
The Schroedinger equation incorporating the long-range Coulomb potential takes the form of a Fredholm equation whose kernel is singular on its diagonal when represented by a basis bearing a continuum of states, such as in a Fourier-Bessel transform. Several methods have been devised to tackle this difficulty, from simply removing the infinite range of the Coulomb potential with a screening or cut function to using discretizing schemes which take advantage of the integrable character of Coulomb kernel singularities. However, they have never been tested in the context of Berggren bases, which allow many-body nuclear wave functions to be expanded with halo or resonant properties within a shell-model framework. It is thus the object of this paper to test different discretization schemes of the Coulomb potential kernel in the framework of complex-energy nuclear physics. For that, the Berggren basis expansion of proton states pertaining to the sd shell arising in the A{approx}20 region, being typically resonant, will be effected. Apart from standard frameworks involving a cut function or analytical integration of singularities, a new method will be presented which replaces diagonal singularities by finite off-diagonal terms. It will be shown that this methodology surpasses in precision the two former techniques.
Virial theorem and Gibbs thermodynamic potential for Coulomb systems
Bobrov, V. B. E-mail: satron@mail.ru; Trigger, S. A. E-mail: satron@mail.ru
2014-10-15
Using the grand canonical ensemble and the virial theorem, we show that the Gibbs thermodynamic potential of the non-relativistic system of charged particles is uniquely defined by single-particle Green functions of electrons and nuclei. This result is valid beyond the perturbation theory with respect to the interparticle interaction.
Morse potential and its relationship with the Coulomb in a position-dependent mass background
B. Bagchi; P. S. Gorain; C. Quesne
2006-12-04
We provide some explicit examples wherein the Schr\\"odinger equation for the Morse potential remains exactly solvable in a position-dependent mass background. Furthermore, we show how in such a context, the map from the full line $(- \\infty, \\infty)$ to the half line $(0, \\infty)$ may convert an exactly solvable Morse potential into an exactly solvable Coulomb one. This generalizes a well-known property of constant-mass problems.
The {sup 6}He Optical Potential at energies around the Coulomb barrier
Fernandez-Garcia, J. P.; Alvarez, M. A. G.; Moro, A. M.
2010-04-26
We present an Optical Model (OM) study of {sup 6}He on {sup 208}Pb elastic scattering data, measured at laboratory energies around the Coulomb barrier (E{sub lab} = 14, 16, 18, 22, and 27 MeV)[1]. For the projectile-target bare interaction, we use the microscopic Sao Paulo Potential (SPP). This bare interaction is supplemented with a Coulomb Dipole Polarization (CDP) potential, as well as a diffuse complex Woods-Saxon potential. Four-body Continuum-Discretized-Coupled-Channels (CDCC) calculations have been performed in order to support the optical model analysis. We have also studied the alpha channel, which is the dominant reaction process. In the analysis of this channel, we compare the angular and energy distributions of the alpha particles measured at 22 MeV, with Distorted Wave Born Approximation (DWBA) calculations.
J. C. N. Carvalho; W. P. Ferreira; G. A. Farias; F. M. Peeters
2010-06-10
We consider a classical system of two-dimensional (2D) charged particles, which interact through a repulsive Yukawa potential $exp(-r/\\lambda)/r$, confined in a parabolic channel which limits the motion of the particles in the $y$-direction. Along the $x$-direction, the particles are also subject to a periodic potential substrate. The ground state configurations and the normal mode spectra of the system are obtained as function of the periodicity and strength of the periodic potential ($V_0$), and density. An interesting set of tunable ground state configurations are found, with first and second order structural transitions between them. A magic configuration with particles aligned in each minimum of the periodic potential is obtained for V_0 larger than some critical value which has a power law dependence on the density. The phonon spectrum of different configurations were also calculated. A localization of the modes into a small frequency interval is observed for a sufficient strength of the periodic potential. A tunable band-gap is found as a function of $V_0$. This model system can be viewed as a generalization of the Frenkel and Kontorova model.
Ho, Choon-Lin
2009-05-15
The four exactly solvable models related to non-sinusoidal coordinates, namely, the Coulomb, Eckart, Rosen-Morse type I and II models are normally being treated separately, despite the similarity of the functional forms of the potentials, their eigenvalues and eigenfunctions. Based on an extension of the prepotential approach to exactly and quasi-exactly solvable models proposed previously, we show how these models can be derived and solved in a simple and unified way.
Quintessence with Yukawa interaction
NASA Astrophysics Data System (ADS)
Costa, André A.; Olivari, Lucas C.; Abdalla, E.
2015-11-01
We consider a quintessence model for dark energy interacting with dark matter via a Yukawa interaction. To put constraints on this model we use the cosmic microwave background measurements from the Planck satellite together with baryon acoustic oscillation, type Ia supernovae and H0 data. We conclude that this is a viable model and an appropriate scalar potential can favor the interacting scenario.
Proton radioactivity with a Yukawa effective interaction
T. R. Routray; S. K. Tripathy; B. B. Dash; B. Behera; D. N. Basu
2011-04-26
The half lives of proton radioactivity of proton emitters are investigated theoretically. Proton-nucleus interaction potentials are obtained by folding the densities of the daughter nuclei with a finite range effective nucleon-nucleon interaction having Yukawa form. The Wood-Saxon density distributions for the nuclei used in calculating the nuclear as well as the Coulomb interaction potentials are predictions of the interaction. The quantum mechanical tunneling probability is calculated within the WKB framework. These calculations provide reasonable estimates for the observed proton radioactivity lifetimes. The effects of neutron-proton effective mass splitting in neutron rich asymmetric matter as well as the nuclear matter incompressibility on the decay probability are investigated.
Nuclear mass formula with a finite-range droplet model and a folded-Yukawa single-particle potential
Moeller, P.; Myers, W.D.; Swiatecki, W.J.; Treiner, J.
1988-07-01
We calculate ground-state masses for 4678 nuclei ranging from /sup 16/O to /sup 318/122 by use of a macroscopic-microscopic model, which incorporates several new features. For the macroscopic model we use the finite-range droplet model which we introduced in 1984. The microscopic contribution is taken from a calculation based on a folded-Yukawa single-particle potential. Some new features now incorporated are a new model for the average pairing strength and the solution of the microscopic pairing equations by use of the Lipkin-Nogami method with approximate particle number conservation. To estimate the parameters of the macroscopic model we use an approach that starts by defining the error of a mass formula in a rigorous way, which leads naturally to the use of experimental uncertainties and of the maximum-likelihood method to derive a set of equations for estimating the parameters and error of the theoretical model. By considering 1593 experimental masses from /sup 16/O to /sup 263/106 we estimate the error of the theoretical model to be 0.769 MeV. The model retains its accuracy far from stability and the values of the model parameters are very insensitive to details of the adjustment procedure. copyright 1988 Academic Press, Inc.
Effect of a relativistic correction to the Coulomb potential on the energy levels of hydrogen atom
Harihar Behera
2012-01-10
Based on classical electrodynamics, it is argued that the Coulomb potential (which is strictly valid for two point charges at rest), commonly used in the study of energy levels of hydrogen atom is not the correct one, because the electron in the hydrogen atom moves with relativistic speeds with respect to the nucleus. Retardation effect has to be considered in accordance with Li\\'{e}nard-Wiechert (or retarded) potential of a moving charge or the relativistic electrodynamics. However, such a consideration introduces a correction to the Coulomb potential, whose quantum mechanical expectation value is estimated at $E_{ret} = - \\frac{mc^2\\alpha ^4}{2n^3(l+1/2)}$, which is of the same order as the fine structure of hydrogen atom and hence added to the standard energy eigenvalue values of H-atom. This correction lifts the $l$-degeneracy in the spectra of H-atom and hence modifies the standard result. The result disturbs the existing agreement between the theory and experiments on H-atom and hence requires further theoretical and experimental re-examination. The implications of this result for the Kepler-problem in general is also discussed in the context of Heaviside's gravity, which seems to offer an alternative explanation for the non-Newtonian perihelion advance of Mercury without invoking the space-time curvature formalism of Einstein's general theory of relativity.
Geilhufe, Matthias; Achilles, Steven; Köbis, Markus Arthur; Arnold, Martin; Mertig, Ingrid; Hergert, Wolfram; Ernst, Arthur
2015-11-01
For a reliable fully-relativistic Korringa-Kohn-Rostoker Green function method, an accurate solution of the underlying single-site scattering problem is necessary. We present an extensive discussion on numerical solutions of the related differential equations by means of standard methods for a direct solution and by means of integral equations. Our implementation is tested and exemplarily demonstrated for a spherically symmetric treatment of a Coulomb potential and for a Mathieu potential to cover the full-potential implementation. For the Coulomb potential we include an analytic discussion of the asymptotic behaviour of irregular scattering solutions close to the origin ([Formula: see text]). PMID:26447352
NASA Astrophysics Data System (ADS)
Geilhufe, Matthias; Achilles, Steven; Köbis, Markus Arthur; Arnold, Martin; Mertig, Ingrid; Hergert, Wolfram; Ernst, Arthur
2015-11-01
For a reliable fully-relativistic Korringa-Kohn-Rostoker Green function method, an accurate solution of the underlying single-site scattering problem is necessary. We present an extensive discussion on numerical solutions of the related differential equations by means of standard methods for a direct solution and by means of integral equations. Our implementation is tested and exemplarily demonstrated for a spherically symmetric treatment of a Coulomb potential and for a Mathieu potential to cover the full-potential implementation. For the Coulomb potential we include an analytic discussion of the asymptotic behaviour of irregular scattering solutions close to the origin (r\\ll 1 ).
Fluid modes of a spherically confined Yukawa plasma
Kaehlert, H.; Bonitz, M.
2010-09-15
The normal modes of a three-dimensional Yukawa plasma in an isotropic harmonic confinement are investigated by solving the linearized cold fluid equations. The eigenmodes are found analytically and expressed in terms of hypergeometric functions. It is found that the mode frequencies solely depend on the dimensionless plasma parameter {xi}={kappa}R, where R is the plasma radius and {kappa} is the inverse screening length. The eigenfrequencies increase monotonically with {xi} and saturate in the limit {xi}{yields}{infinity}. Compared with the results in the Coulomb limit [D. H. E. Dubin, Phys. Rev. Lett. 66, 2076 (1991)], we find an additional class of modes characterized by the number n which determines the number of radial nodes in the perturbed potential. These modes originate from the degenerate bulk modes of the Coulomb system. Analytical formulas for the eigenfrequencies are derived for limiting cases.
Competition between Coulomb and Symmetry Potential in Semi-peripheral Heavy-ion Collisions
Qianghua Wu; Yingxun Zhang; Zhigang Xiao; Rensheng Wang; Yang Zhang; Zhuxia Li; Ning Wang; R. H. Schowalter
2015-01-17
The anisotropy of angular distributions of emitted nucleons and light charged particles for the asymmetric reaction system, $^{40}$Ar+$^{197}$Au, at b=6fm and $E_{beam}$=35, 50 and 100MeV/u, are investigated by using the Improved Quantum Molecular Dynamics model. The competition between the symmetry potential and Coulomb potential shows large impacts on the nucleons and light charged particles emission in projectile and target region. As a result of this competition, the angular distribution anisotropy of coalescence invariant Y(n)/Y(p) ratio at forward regions shows sensitivity to the stiffness of symmetry energy as well as the value of Y(n)/Y(p). This observable can be further checked against experimental data to understand the reaction mechanism and to extract information about the symmetry energy at subsaturation densities.
B. J. Wundt; U. D. Jentschura
2015-08-14
We investigate the coupling of the electromagnetic sources (charge and current densities) to the scalar and vector potentials in classical electrodynamics, using Green function techniques. As is well known, the scalar potential shows an action-at-a-distance behavior in Coulomb gauge. The conundrum generated by the instantaneous interaction has intrigued physicists for a long time. Starting from the differential equations that couple the sources to the potentials, we here show in a concise derivation, using the retarded Green function, how the instantaneous interaction cancels in the calculation of the electric field. The time derivative of a specific additional term in the vector potential, present only in Coulomb gauge, yields a supplementary contribution to the electric field which cancels the gradient of the instantaneous Coulomb gauge scalar potential, as required by gauge invariance. This completely eliminates the contribution of the instantaneous interaction from the electric field. It turns out that a careful formulation of the retarded Green function, inspired by field theory, is required in order to correctly treat boundary terms in partial integrations. Finally, compact integral representations are derived for the Lienard-Wiechert potentials (scalar and vector) in Coulomb gauge which manifestly contain two compensating action-at-a-distance terms.
Non-asymptotic Yukawa scattering
NASA Astrophysics Data System (ADS)
Stenson, J.; Stetz, A.
2015-11-01
A general non-asymptotic solution is given for the quantum Yukawa scattering problem in terms of Legendre functions of the second kind. It is visualized and shown to match the standard result in the asymptotic limit. We also briefly indicate how the result contributes to three problems that have heretofore been obscured by the usual approximations: it clarifies the meaning of the differential cross section by providing a generalizing case, it illustrates the breakdown of the assumption that scattering currents are only radially outward which leads to fundamental interpretive issues, and it provides a way to incrementally and rigorously investigate the Coulomb limit of scattering.
Phase diagram and critical properties of Yukawa bilayers
NASA Astrophysics Data System (ADS)
Trav?nec, Igor; Šamaj, Ladislav
2015-08-01
We study the ground-state Wigner bilayers of pointlike particles with Yukawa pairwise interactions, confined to the surface of two parallel hard walls at dimensionless distance ? . The model involves as limiting cases the unscreened Coulomb potential and hard spheres. The phase diagram of Yukawa particles, studied numerically by Messina and Löwen [Phys. Rev. Lett. 91, 146101 (2003), 10.1103/PhysRevLett.91.146101], exhibits five different staggered phases as ? varies from 0 to intermediate values. We present a lattice summation method using the generalized Misra functions which permits us to calculate the energy per particle of the phases with a precision much higher than usual in computer simulations. This allows us to address some tiny details of the phase diagram. Going from the hexagonal phase I to phase II is shown to occur at ? =0 . All second-order phase transitions are proved to be of mean-field type. We also derive the asymptotic shape of critical lines close to the Coulomb and hard-spheres limits. In and close to the hard-spheres limit, the dependence of the internal parameters of the present phases on ? is determined exactly.
Phase diagram and critical properties of Yukawa bilayers
Igor Travenec; Ladislav Samaj
2015-04-14
We study the ground-state Wigner bilayers of pointlike particles with Yukawa pairwise interactions, confined to the surface of two parallel hard walls at dimensionless distance $\\eta$. The model involves as limiting cases the unscreened Coulomb potential and hard spheres. The phase diagram of Yukawa particles, studied numerically by Messina and L\\"owen [Phys. Rev. Lett. 91 (2003) 146101], exhibits five different staggered phases as $\\eta$ varies from 0 to intermediate values. We present a lattice summation method using the generalized Misra functions which permits us to calculate the energy per particle of the phases with a precision much higher than usual in computer simulations. This allows us to address some tiny details of the phase diagram. Going from the hexagonal phase I to phase II is shown to occur at $\\eta=0$, which resolves a longtime controversy. We find a tricritical point where Messina and L\\"owen suggested a coexistence domain of several phases which was suggested to divide the staggered rhombic phase into two separate regions. Our calculations reveal one continuous region for this rhombic phase with a very narrow connecting channel. Further we show that all second-order phase transitions are of mean-field type. We also derive the asymptotic shape of critical lines close to the Coulomb and hard-spheres limits. In and close to the hard-spheres limit, the dependence of the internal parameters of the present phases on $\\eta$ is determined exactly.
NASA Astrophysics Data System (ADS)
Chapela, Gustavo A.; del Río, Fernando; Alejandre, José
2013-02-01
The liquid-vapor phase diagrams of equal size diameter ? binary mixtures of screened potentials have been reported for several ranges of interaction using Monte Carlo simulation methods [J. B. Caballero, A. M. Puertas, A. Fer?andez-Barbero, F. J. de las Nieves, J. M. Romero-Enrique, and L. F. Rull, J. Chem. Phys. 124, 054909 (2006), 10.1063/1.2159481; A. Fortini, A.-P. Hynninen, and M. Dijkstra, J. Chem. Phys. 125, 094502 (2006), 10.1063/1.2335453]. Both works report controversial results about the stability of the phase diagram with the inverse Debye screening length ?. Caballero found stability for values of ?? up to 20 while Fortini reported stability for ?? up to 20 while Fortini reported stability for ?? ? 4. In this work a spinodal decomposition process where the liquid and vapor phases coexist through an interface in a slab geometry is used to obtain the phase equilibrium and surface properties using a discontinuous molecular dynamics simulations for mixtures of equal size particles carrying opposite charge and interacting with a mixture of attractive and repulsive Yukawa potentials at different values of ??. An crude estimation of the triple point temperatures is also reported. The isothermal-isobaric method was also used to determine the phase stability using one phase simulations. We found that liquid-vapor coexistence is stable for values of ?? > 20 and that the critical temperatures have a maximum value at around ?? = 10, in agreement with Caballero et al. calculations. There also exists a controversy about the liquid-vapor envelope stability of the pure component attractive Yukawa model which is also discussed in the text. In addition, details about the equivalence between continuous and discontinuous molecular dynamics simulations are given, in the Appendix, for Yukawa and Lennard-Jones potentials.
Chapela, Gustavo A; del Río, Fernando; Alejandre, José
2013-02-01
The liquid-vapor phase diagrams of equal size diameter ? binary mixtures of screened potentials have been reported for several ranges of interaction using Monte Carlo simulation methods [J. B. Caballero, A. M. Puertas, A. Fern?andez-Barbero, F. J. de las Nieves, J. M. Romero-Enrique, and L. F. Rull, J. Chem. Phys. 124, 054909 (2006); A. Fortini, A.-P. Hynninen, and M. Dijkstra, J. Chem. Phys. 125, 094502 (2006)]. Both works report controversial results about the stability of the phase diagram with the inverse Debye screening length ?. Caballero found stability for values of ?? up to 20 while Fortini reported stability for ?? up to 20 while Fortini reported stability for ?? ? 4. In this work a spinodal decomposition process where the liquid and vapor phases coexist through an interface in a slab geometry is used to obtain the phase equilibrium and surface properties using a discontinuous molecular dynamics simulations for mixtures of equal size particles carrying opposite charge and interacting with a mixture of attractive and repulsive Yukawa potentials at different values of ??. An crude estimation of the triple point temperatures is also reported. The isothermal-isobaric method was also used to determine the phase stability using one phase simulations. We found that liquid-vapor coexistence is stable for values of ?? > 20 and that the critical temperatures have a maximum value at around ?? = 10, in agreement with Caballero et al. calculations. There also exists a controversy about the liquid-vapor envelope stability of the pure component attractive Yukawa model which is also discussed in the text. In addition, details about the equivalence between continuous and discontinuous molecular dynamics simulations are given, in the Appendix, for Yukawa and Lennard-Jones potentials. PMID:23406133
Information-Theoretic Properties of the Half-Line Coulomb Potential
J. J. Omiste; R. J. Yanez; J. S. Dehesa
2009-09-02
The half-line one-dimensional Coulomb potential is possibly the simplest D-dimensional model with physical solutions which has been proved to be successful to describe the behaviour of Rydberg atoms in external fields and the dynamics of surface-state electrons in liquid helium, with potential applications in constructing analog quantum computers and other fields. Here, we investigate the spreading and uncertaintylike properties for the ground and excited states of this system by means of the logarithmic measure and the information-theoretic lengths of Renyi, Shannon and Fisher types; so, far beyond the Heisenberg measure. In particular, the Fisher length (which is a local quantity of internal disorder) is shown to be the proper measure of uncertainty for our system in both position and momentum spaces. Moreover the position Fisher length of a given physical state turns out to be not only directly proportional to the number of nodes of its associated wavefunction, but also it follows a square-root energy law.
Interatomic Coulombic decay in a He dimer: Ab initio potential-energy curves and decay widths
Kolorenc, Premysl; Kryzhevoi, Nikolai V.; Sisourat, Nicolas; Cederbaum, Lorenz S.
2010-07-15
The energy gained by either of the two helium atoms in a helium dimer through simultaneous ionization and excitation can be efficiently transferred to the other helium atom, which then ionizes. The respective relaxation process called interatomic Coulombic decay (ICD) is the subject of the present paper. Specifically, we are interested in ICD of the lowest of the ionized excited states, namely, the He{sup +}(n=2)He states, for which we calculated the relevant potential-energy curves and the interatomic decay widths. The full-configuration interaction method was used to obtain the potential-energy curves. The decay widths were computed by utilizing the Fano ansatz, Green's-function methods, and the Stieltjes imaging technique. The behavior of the decay widths with the interatomic distance is examined and is elucidated, whereby special emphasis is given to the asymptotically large interatomic separations. Our calculations show that the electronic ICD processes dominate over the radiative decay mechanisms over a wide range of interatomic distances. The ICD in the helium dimer has recently been measured by Havermeier et al. [Phys. Rev. Lett. 104, 133401 (2010)]. The impact of nuclear dynamics on the ICD process is extremely important and is discussed by Sisourat et al. [Nat. Phys. 6, 508 (2010)] based on the ab initio data computed in the present paper.
Analytic structure of the multichannel Jost matrix for potentials with Coulombic tails
Rakityansky, S. A.; Elander, N.
2013-12-15
A quantum system is considered that can move in N two-body channels with the potentials that may include the Coulomb interaction. For this system, the Jost matrix is constructed in such a way that all its dependencies on the channel momenta and Sommerfeld parameters are factorized in the form of explicit analytic expressions. It is shown that the two remaining unknown matrices are single-valued analytic functions of the energy and therefore can be expanded in the Taylor series near an arbitrary point within the domain of their analyticity. It is derived a system of first-order differential equations whose solutions determine the expansion coefficients of these series. Alternatively, the unknown expansion coefficients can be used as fitting parameters for parametrizing experimental data similarly to the effective-range expansion. Such a parametrization has the advantage of preserving proper analytic structure of the Jost matrix and can be done not only near the threshold energies, but around any collision or even complex energy. As soon as the parameters are obtained, the Jost matrix (and therefore the S-matrix) is known analytically on all sheets of the Riemann surface, and thus enables one to locate possible resonances.
Symmetry and degeneracy of the curved Coulomb potential on the S3 ball
Adrian Pallares Rivera; Mariana Kirchbach
2012-02-09
The "curved" Coulomb potential on the S3 ball, whose isometry group is SO(4), takes the form of a cotangent function, and when added to the four-dimensional squared angular momentum operator, one of the so(4) Casimir invariants, a Hamiltonian is obtained which describes a perturbance of the free geodesic motion that results peculiar in several aspects. The spectrum of such a motion has been studied on various occasions and is known to carry unexpectedly so(4) degeneracy patterns despite the non-commutativity of the perturbance with the Casimir operator. We here suggest an explanation for this behavior in designing a set of operators which close the so(4) algebra and whose Casimir invariant coincides with the Hamiltonian of the perturbed motion at the level of the eigenvalue problem. The above operators are related to the canonical geometric SO(4) generators on S3 by a non-unitary similarity transformation of the scaling type. In this fashion, we identify a complementary option to the deformed dynamical so(4) Higgs algebra constructed in terms of the components of the ordinary angular momentum and a related Runge-Lenz vector.
Cluster decay half lives of trans-lead nuclei within the Coulomb and proximity potential model
K. P. Santhosh; B. Priyanka; M. S. Unnikrishnan
2012-07-18
Within the Coulomb and proximity potential model (CPPM) the cluster decay process in {199-226}^Fr, {206-232}^Ac, {209-237}^Th, {212-238}^Pa, {217-241}^U, {225-242}^Np, {225-244}^Pu, {231-246}^Am, {202-230}^Ra and {233-249}^Cm isotopes leading to the doubly magic 208^Pb and neighbouring nuclei are studied. The computed half lives are compared with available experimental data and are in good agreement with each other. The half lives are also computed using the Universal formula for cluster decay (UNIV) of Poenaru et al, Universal decay law (UDL) and the scaling law of Horoi et al, and their comparisons with CPPM values are found to be in agreement. The calculations for the emission of 22^O, 20^O, 20^O from the parents {209-237}^Th, {202-230}^Ra and {217-240}^U respectively were the experimental values are not available are also done. It is found that most of the decay modes are favourable for measurement, and this observation will serve as a guide to the future experiments. The odd-even staggering (OES) are found to be more prominent in the emission of odd mass clusters. The Geiger - Nuttall plots of log_10(T_1/2) vs. Q^{-1/2} for various clusters ranging from 14^C to 34^Si from different isotopes of heavy parent nuclei with atomic numbers within the range 87 \\leq Z \\leq 96 have been studied and are found to be linear. Our study reveals the role of doubly magic 208^Pb daughter nuclei in cluster decay process and also reveal the fact that the role of neutron shell closure is crucial than proton shell closure.
Bo, Iselin M. Th.; Esser, Ruth; Lie-Svendsen, Oystein E-mail: ruth.esser@uit.no
2013-05-20
We model the effect of gravitational settling in the upper chromosphere on O, Fe, Si, and Ne, studying whether Coulomb collisions between ionized low First Ionization Potential (FIP) elements and protons is sufficient to cause abundance enhancements relative to oxygen. We find that low-FIP abundance enhancements comparable to observed values can be obtained provided the hydrogen ionization degree lies in the approximate range 10%-30%, which agrees with chromospheric models. Lower or higher hydrogen ionization causes the FIP-effect to become smaller or absent (depletion of all heavy elements). Iron must be almost fully ionized in order to become enriched relative to high-FIP elements, and this requires a high iron photoionization rate. The time scale necessary to produce the enrichment increases rapidly with increasing H ionization. For iron in a background from a semiempirical chromospheric model, with an H ion fraction of the order of 30%-40% in the upper chromosphere, 1-2 hr of settling is required to produce enhancements comparable to observations. The absolute abundance (relative to H), which monotonically decreases with time during settling, has by that time decreased by less than 50% in the same altitude region. With the same background conditions, the silicon abundance is more strongly enhanced by the settling than the iron abundance. The high-FIP element neon is depleted, relative to O and low-FIP elements, in the same background and altitude region where iron is enhanced, typically by 50% or more relative to O after 1-2 hr of settling.
The Coulomb interaction in Helium-3: Interplay of strong short-range and weak long-range potentials
J. Kirscher; D. Gazit
2015-10-01
Quantum chromodynamics and the electroweak theory at low energies are prominent instances of the combination of a short-range and a long-range interaction. For the description of light nuclei, the large nucleon-nucleon scattering lengths produced by the strong interaction, and the reduction of the weak interaction to the Coulomb potential, play a crucial role. Helium-3 is the first bound nucleus comprised of more than one proton in which this combination of forces can be studied. We demonstrate a proper renormalization of Helium-3 using the pionless effective field theory as the formal representation of the nuclear regime as strongly interacting fermions. The theory is found consistent at leading and next-to-leading order without isospin-symmetry-breaking 3-nucleon interactions and a non-perturbative treatment of the Coulomb interaction. The conclusion highlights the significance of the regularization method since a comparison to previous work is contradictory if the difference in those methods is not considered. With a perturbative Coulomb interaction, as suggested by dimensional analysis, we find the Helium-3 system properly renormalized, too. For both treatments, renormalization-scheme independence of the effective field theory is demonstrated by regulating the potential and a variation of the associated cutoff.
Bakke, K.
2014-02-15
We discuss the arising of bound states solutions of the Schrödinger equation due to the presence of a Coulomb-type potential induced by the interaction between a moving electric quadrupole moment and a magnetic field. Furthermore, we study the influence of the Coulomb-type potential on the harmonic oscillator by showing a quantum effect characterized by the dependence of the angular frequency on the quantum numbers of the system, whose meaning is that not all values of the angular frequency are allowed. -- Highlights: • Interaction between a moving electric quadrupole moment and a magnetic field. • Arising of bound states solutions due to the presence of a Coulomb-type potential. • Influence of the Coulomb-type potential on the harmonic oscillator. • Dependence of the angular frequency on the quantum numbers of the system.
NASA Astrophysics Data System (ADS)
Lai, X.-Y.; Poli, C.; Schomerus, H.; Faria, C. Figueira de Morisson
2015-10-01
We perform a detailed analysis of how the interplay between the residual binding potential and a strong laser field influences above-threshold ionization (ATI), employing a semianalytical, Coulomb-corrected strong-field approximation (SFA) in which the Coulomb potential is incorporated in the electron propagation in the continuum. We find that the Coulomb interaction lifts the degeneracy of some SFA trajectories and we identify a set of orbits that, for high enough photoelectron energies, may be associated with rescattering. Furthermore, by performing a direct comparison with the standard SFA, we show that several features in the ATI spectra can be traced back to the influence of the Coulomb potential on different electron trajectories. These features include a decrease in the contrast, a shift towards lower energies in the interference substructure, and an overall increase in the photoelectron yield. All features encountered exhibit very good agreement with the ab initio solution of the time-dependent Schrödinger equation.
Modesto-Costa, Lucas; Canuto, Sylvio; Mukherjee, Prasanta K.
2015-03-15
A detailed investigation of the magnetic dipolar and quadrupolar excitation energies and transition probabilities of helium isoelectronic He, Be{sup 2+}, C{sup 4+}, and O{sup 6+} have been performed under exponential cosine screened Coulomb potential generated in a plasma environment. The low-lying excited states 1s{sup 2}:{sup 1}S{sup e} ? 1sns:{sup 3}S{sup e}{sub 0}, and 1snp:{sup 3}P{sup o}{sub 2} (n?=?2, 3, 4, and 5) are considered. The variational time-dependent coupled Hartree-Fock scheme has been used. The effect of the confinement produced by the potential on the structural properties is investigated for increasing coupling strength of the plasma. It is noted that there is a gradual destabilization of the energy of the system with the reduction of the ionization potential and the number of excited states. The effect of the screening enhancement on the excitation energies and transition probabilities has also been investigated and the results compared with those available for the free systems and under the simple screened Coulomb potential.
Popescu, Radian; Mueller, Erich; Wanner, Matthias; Gerthsen, Dagmar; Schowalter, Marco; Rosenauer, Andreas; Boettcher, Artur; Loeffler, Daniel; Weis, Patrick
2007-12-15
Electron holography in a transmission electron microscope was applied to measure the phase shift {delta}{phi} induced by Au clusters as a function of the cluster size. Large {delta}{phi} observed for small Au clusters cannot be described by the well-known equation {delta}{phi}=C{sub E}V{sub 0}t (C{sub E}, interaction constant; V{sub 0}, mean inner Coulomb potential (MIP) of bulk gold; and t, cluster thickness). The rapid increase of the Au MIP with decreasing cluster size derived from {delta}{phi} can be explained by the compressive strain of surface atoms in the cluster.
The Coulomb interaction in Helium-3: Interplay of strong short-range and weak long-range potentials
Kirscher, J
2015-01-01
Quantum chromodynamics and the electroweak theory at low energies are prominent instances of the combination of a short-range and a long-range interaction. For the description of light nuclei, the large nucleon-nucleon scattering lengths produced by the strong interaction, and the reduction of the weak interaction to the Coulomb potential, play a crucial role. Helium-3 is the first bound nucleus comprised of more than one proton in which this combination of forces can be studied. We demonstrate a proper renormalization of Helium-3 using the pionless effective field theory as the formal representation of the nuclear regime as strongly interacting fermions. The theory is found consistent at leading and next-to-leading order without isospin-symmetry-breaking 3-nucleon interactions and a non-perturbative treatment of the Coulomb interaction. The conclusion highlights the significance of the regularization method since a comparison to previous work is contradictory if the difference in those methods is not conside...
Effective Coulomb logarithm for one component plasma
Khrapak, Sergey A.
2013-05-15
An expression for the effective Coulomb logarithm in one-component-plasma is proposed, which allows to extend the applicability of the classical formula for the self-diffusion coefficient to the strongly coupled regime. The proposed analytical approximation demonstrates reasonable agreement with previous numerical simulation results. Relevance to weakly screened Yukawa systems (and, in particular, complex plasmas) is discussed.
W. Glockle; J. Golak; R. Skibinski; H. Witala
2009-03-02
The 3-dimensional wave function for a sharply cut-off Coulomb potential is analytically derived. The asymptotic form of the related scattering amplitude reveals a failure of the standard renormalization factor which is believed to be generally valid for any type of screening.
NASA Astrophysics Data System (ADS)
Sato, Humitaka
2008-06-01
Life history of Hideki Yukawa is described, together with that of Sin-itiro Tomonaga. They grew upiin Kyoto city and were classmate. Their independency and collaboration had contributed to the growth of physics research in Japan after the end of WWII.
Gönül, B; Koçak, M; Gonul, Bulent; Ozer, Okan; Kocak, Mehmet
2001-01-01
The eigenvalues of the potentials $V(r)=\\frac{A_{1}}{r}+A_{2}+A_{3}r+A_{4}r^{2}+A_{5}r^{3}+A_{6}r^{4}$ and $V(r)=B_{1}r^{2}+B_{2}r^{4}+B_{3}r^{6}+B_{4}r^{8}+B_{5}r^{10}$ are obtained in $N$-dimensional space by the Lagrange-mesh calculations for a wide range of values of the parameters. We discuss the explicit dependence of these two potentials in higher-dimensional space. Using the formalism of supersymmetric quantum mechanics, it is shown that exact solutions of these potentials exist when the parameters satisfy certain constraints.
Nicolas Michel
2008-02-12
Demonstrating the completeness of wave functions solutions of the radial Schrodinger equation is a very difficult task. Existing proofs, relying on operator theory, are often very abstract and far from intuitive comprehension. However, it is possible to obtain rigorous proofs amenable to physical insight, if one restricts the considered class of Schrodinger potentials. One can mention in particular unbounded potentials yielding a purely discrete spectrum and short-range potentials. However, those possessing a Coulomb tail, very important for physical applications, have remained problematic due to their long-range character. The method proposed in this paper allows to treat them correctly, provided the non-Coulomb part of potentials vanishes after a finite radius. Non-locality of potentials can also be handled. The main idea in the proposed demonstration is that regular solutions behave like sine/cosine functions for large momenta, so that their expansions verify Fourier transform properties. The highly singular point at k = 0 of long-range potentials is dealt with properly using analytical properties of Coulomb wave functions. Lebesgue measure theory is avoided, rendering the demonstration clear from a physical point of view.
Banerjee, S.N.; Chakraborty, S.N.
1980-03-01
An approach related to the teaching of the chapter on bound and scattering states in a short-range potential, which forms a standard part of quantum-mechanics course, is outlined with an example. The proposed interaction closely approximates the realistic Yukawa potential. It also represents the Coulomb potential in a limiting case. Investigation of the Schroedinger equation with the potential may serve as an excellent demonstration to be incorporated in the undergraduate quantum-mechanics or nuclear physics course.
Eigenmodes and thermodynamics of a Coulomb chain in a harmonic potential
Giovanna Morigi; Shmuel Fishman
2004-02-18
The density of ions trapped in a harmonic potential in one dimension is not uniform. Consequently the eigenmodes are not phonons. We calculate the long wavelength modes in the continuum limit, and evaluate the density of states in the short wavelength limit for chains of $N\\gg 1$ ions. Remarkably, the results that are found analytically in the thermodynamic limit provide a good estimate of the spectrum of excitations of small chains down to few tens of ions. The spectra are used to compute the thermodynamic functions of the chain. Deviations from extensivity of the thermodynamic quantities are found. An analytic expression for the critical transverse frequency determining the stability of a linear chain is derived.
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.
Density profile of strongly correlated spherical Yukawa plasmas
NASA Astrophysics Data System (ADS)
Bonitz, M.; Henning, C.; Ludwig, P.; Golubnychiy, V.; Baumgartner, H.; Piel, A.; Block, D.
2006-10-01
Recently the discovery of 3D-dust crystals [1] excited intensive experimental and theoretical activities [2-4]. Details of the shell structure of these crystals has been very well explained theoretically by a simple model involving an isotropic Yukawa-type pair repulsion and an external harmonic confinement potential [4]. On the other hand, it has remained an open question how the average radial density profile, looks like. We show that screening has a dramatic effect on the density profile, which we derive analytically for the ground state. Interestingly, the result applies not only to a continuous plasma distribution but also to simulation data for the Coulomb crystals exhibiting the above mentioned shell structure. Furthermore, excellent agreement between the continuum model and shell models is found [5]. [1] O. Arp, D. Block, A. Piel, and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004). [2] H. Totsuji, C. Totsuji, T. Ogawa, and K. Tsuruta, Phys. Rev. E 71, 045401 (2005) [3] P. Ludwig, S. Kosse, and M. Bonitz, Phys. Rev. E 71, 046403 (2005) [4] M. Bonitz, D. Block, O. Arp, V. Golubnychiy, H. Baumgartner, P. Ludwig, A. Piel, and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006) [5] C. Henning, M. Bonitz, A. Piel, P. Ludwig, H. Baumgartner, V. Golubnichiy, and D. Block, submitted to Phys. Rev. E
NASA Astrophysics Data System (ADS)
Haxhimali, Tomorr; Rudd, Robert E.; Cabot, William H.; Graziani, Frank R.
2015-11-01
We present molecular dynamics (MD) calculations of shear viscosity for asymmetric mixed plasma for thermodynamic conditions relevant to astrophysical and inertial confinement fusion plasmas. Specifically, we consider mixtures of deuterium and argon at temperatures of 100-500 eV and a number density of 1025 ions/cc. The motion of 30 000-120 000 ions is simulated in which the ions interact via the Yukawa (screened Coulomb) potential. The electric field of the electrons is included in this effective interaction; the electrons are not simulated explicitly. Shear viscosity is calculated using the Green-Kubo approach with an integral of the shear stress autocorrelation function, a quantity calculated in the equilibrium MD simulations. We systematically study different mixtures through a series of simulations with increasing fraction of the minority high-Z element (Ar) in the D-Ar plasma mixture. In the more weakly coupled plasmas, at 500 eV and low Ar fractions, results from MD compare very well with Chapman-Enskog kinetic results. In the more strongly coupled plasmas, the kinetic theory does not agree well with the MD results. We develop a simple model that interpolates between classical kinetic theories at weak coupling and the Murillo Yukawa viscosity model at higher coupling. This hybrid kinetics-MD viscosity model agrees well with the MD results over the conditions simulated, ranging from moderately weakly coupled to moderately strongly coupled asymmetric plasma mixtures.
ERIC Educational Resources Information Center
Fay, Temple H.
2012-01-01
Viscous damping is commonly discussed in beginning differential equations and physics texts but dry friction or Coulomb friction is not despite dry friction being encountered in many physical applications. One reason for avoiding this topic is that the equations involve a jump discontinuity in the damping term. In this article, we adopt an energy…
Kadyrov, A S; Bray, I; Mukhamedzhanov, A M; Stelbovics, A T
2008-12-01
We formulate scattering theory in the framework of a surface-integral approach utilizing analytically known asymptotic forms of the three-body wave functions. This formulation is valid for both short-range and Coulombic potentials. The post and prior forms of the breakup amplitude are derived without any reference to renormalization procedures. PMID:19113531
Shimazaki, Tomomi; Nakajima, Takahito
2014-09-21
We previously reported a screened Hartree-Fock (HF) exchange potential for energy band structure calculations [T. Shimazaki and Y. Asai, J. Chem. Phys. 130, 164702 (2009); T. Shimazaki and Y. Asai, J. Chem. Phys. 132, 224105 (2010)]. In this paper, we discuss the Coulomb-hole (COH) interaction and screened Slater-formula and determine the energy band diagrams of several semiconductors, such as diamond, silicon, AlAs, AlP, GaAs, GaP, and InP, based on the screened HF exchange potential and Slater-formula with COH interaction, to demonstrate the adequacy of those theoretical concepts. The screened HF exchange potential and Slater-formula are derived from a simplified dielectric function and, therefore, include the dielectric constant in their expressions. We also present a self-consistent calculation technique to automatically determine the dielectric constant, which is incorporated into each self-consistent field step. PMID:25240347
NASA Astrophysics Data System (ADS)
Shimazaki, Tomomi; Nakajima, Takahito
2014-09-01
We previously reported a screened Hartree-Fock (HF) exchange potential for energy band structure calculations [T. Shimazaki and Y. Asai, J. Chem. Phys. 130, 164702 (2009); T. Shimazaki and Y. Asai, J. Chem. Phys. 132, 224105 (2010)]. In this paper, we discuss the Coulomb-hole (COH) interaction and screened Slater-formula and determine the energy band diagrams of several semiconductors, such as diamond, silicon, AlAs, AlP, GaAs, GaP, and InP, based on the screened HF exchange potential and Slater-formula with COH interaction, to demonstrate the adequacy of those theoretical concepts. The screened HF exchange potential and Slater-formula are derived from a simplified dielectric function and, therefore, include the dielectric constant in their expressions. We also present a self-consistent calculation technique to automatically determine the dielectric constant, which is incorporated into each self-consistent field step.
Improved Shell models for screened Coulomb balls
NASA Astrophysics Data System (ADS)
Bonitz, M.; Kaehlert, H.; Henning, C.; Baumgartner, H.; Filinov, A.
2006-10-01
Spherical Coulomb crystals in dusty plasmas [1] are well described by an isotropic Yukawa-type pair interaction and an external parabolic confinement as was shown by extensive molecular dynamics simulations [2]. A much simpler description is possible with analytical shell models which have been derived for Yukawas plasmas in [3,4]. Here we analyze improved Yukawa shell models which include correlations along the lines proposed for Coulomb crystals in [5]. The shell configurations are efficiently evaluated using a Monte Carlo procedure. [1] O. Arp, A. Piel and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004). [2] M. Bonitz, D. Block, O. Arp, V. Golunychiy, H. Baumgartner, P. Ludwig, A. Piel and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006). [3] H. Totsuji, C. Totsuji, T. Ogawa, and K. Tsuruta, Phys. Rev. E 71, 045401 (2005). [4] C. Henning, M. Bonitz, A. Piel, P. Ludwig, H. Baumgartner, V. Golubnichiy, and D. Block, submitted to Phys. Rev. E [5] W.D. Kraeft and M. Bonitz, J. Phys. Conf. Ser. 35, 94 (2006).
Coulomb crystallization in classical and quantum systems
NASA Astrophysics Data System (ADS)
Bonitz, Michael
2007-11-01
Coulomb crystallization occurs in one-component plasmas when the average interaction energy exceeds the kinetic energy by about two orders of magnitude. A simple road to reach such strong coupling consists in using external confinement potentials the strength of which controls the density. This has been succsessfully realized with ions in traps and storage rings and also in dusty plasma. Recently a three-dimensional spherical confinement could be created [1] which allows to produce spherical dust crystals containing concentric shells. I will give an overview on our recent results for these ``Yukawa balls'' and compare them to experiments. The shell structure of these systems can be very well explained by using an isotropic statically screened pair interaction. Further, the thermodynamic properties of these systems, such as the radial density distribution are discussed based on an analytical theory [3]. I then will discuss Coulomb crystallization in trapped quantum systems, such as mesoscopic electron and electron hole plasmas in coupled layers [4,5]. These systems show a very rich correlation behavior, including liquid and solid like states and bound states (excitons, biexcitons) and their crystals. On the other hand, also collective quantum and spin effects are observed, including Bose-Einstein condensation and superfluidity of bound electron-hole pairs [4]. Finally, I consider Coulomb crystallization in two-component neutral plasmas in three dimensions. I discuss the necessary conditions for crystals of heavy charges to exist in the presence of a light component which typically is in the Fermi gas or liquid state. It can be shown that their exists a critical ratio of the masses of the species of the order of 80 [5] which is confirmed by Quantum Monte Carlo simulations [6]. Familiar examples are crystals of nuclei in the core of White dwarf stars, but the results also suggest the existence of other crystals, including proton or ?-particle crystals in dense matter and of hole crystals in semiconductors. [1] O. Arp, D. Block, A. Piel, and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004). [2] M. Bonitz, D. Block, O. Arp, V. Golubnychiy, H. Baumgartner, P. Ludwig, A. Piel, and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006). [3] C. Henning, H. Baumgartner, A. Piel, P. Ludwig, V. Golubnychiy, M. Bonitz, and D. Block, Phys. Rev. E 74, 056403 (2006) and Phys. Rev. E (2007). [4] A. Filinov, M. Bonitz, and Yu. Lozovik, Phys. Rev. Lett. 86, 3851 (2001). [5] M. Bonitz, V. Filinov, P. Levashov, V. Fortov, and H. Fehske, Phys. Rev. Lett. 95, 235006 (2005) and J. Phys. A: Math. Gen. 39, 4717 (2006). [6] Introduction to Computational Methods for Many-Body Systems, M. Bonitz and D. Semkat (eds.), Rinton Press, Princeton (2006)
Coulombic contribution and fat center vortex model
Rafibakhsh, Shahnoosh; Deldar, Sedigheh
2007-02-27
The fat (thick) center vortex model is one of the phenomenological models which is fairly successful to interpret the linear potential between static sources. However, the Coulombic part of the potential has not been investigated by the model yet. In an attempt to get the Coulombic contribution and to remove the concavity of the potentials, we are studying different vortex profiles and vortex sizes.
Relativistic Newton and Coulomb Laws
Zinoviev, Yury M
2008-01-01
The relativistic equations for the electromagnetic and gravitation interactions are similar: The only Lagrangian equation is the equation with Lorentz force. The potential satisfies the wave equation with the right - hand side proprtional to the velocity of another particle multiplied by the delta - function concentrated at the position of another particle. If the interaction propagates at the speed of light, then the wave equation has the unique solution: the Lienard - Wiechert potential. The Maxwell equations are completely defined by the obtained relativistic Coulomb law. The Coulomb law and the Newton gravity law differ from each other only in the choice of the constants. If we choose in Coulomb law the electric charges equal to the masses and choose the interaction constant of another sign, then we get Newton gravity law. If we choose in the relativistic Coulomb law the electric charges equal to the masses and choose the interaction constant of another sign, then we get the relativistic Newton gravity la...
Relativistic Newton and Coulomb Laws
Yury M. Zinoviev
2008-01-07
The relativistic equations for the electromagnetic and gravitation interactions are similar: The only Lagrangian equation is the equation with Lorentz force. The potential satisfies the wave equation with the right - hand side proprtional to the velocity of another particle multiplied by the delta - function concentrated at the position of another particle. If the interaction propagates at the speed of light, then the wave equation has the unique solution: the Lienard - Wiechert potential. The Maxwell equations are completely defined by the obtained relativistic Coulomb law. The Coulomb law and the Newton gravity law differ from each other only in the choice of the constants. If we choose in Coulomb law the electric charges equal to the masses and choose the interaction constant of another sign, then we get Newton gravity law. If we choose in the relativistic Coulomb law the electric charges equal to the masses and choose the interaction constant of another sign, then we get the relativistic Newton gravity law.
Coulomb string tension, asymptotic string tension, and the gluon chain
Greensite, Jeff; Szczepaniak, Adam P.
2015-02-01
We compute, via numerical simulations, the non-perturbative Coulomb potential and position-space ghost propagator in pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.
Yukawa alignment in the two-Higgs-doublet model
Pich, Antonio; Tuzon, Paula
2009-11-01
In multi-Higgs-doublet models the alignment in flavor space of the relevant Yukawa matrices guarantees the absence of tree-level flavor-changing couplings of the neutral scalar fields. We analyze the consequences of this condition within the two-Higgs-doublet model and show that it leads to a generic Yukawa structure which contains as particular cases all known specific implementations of the model based on Z{sub 2} symmetries. All possible freedom in the Yukawa sector gets parametrized in terms of three complex couplings {sigma}{sub f}. In spite of having flavor conservation in the neutral scalar couplings, the phases of these three parameters represent potential new sources of CP violation.
Shear viscosity and shear thinning in two-dimensional Yukawa liquids
Z. Donkó; J. Goree; P. Hartmann; K. Kutasi
2006-03-24
A two-dimensional Yukawa liquid is studied using two different nonequilibrium molecular dynamics simulation methods. Shear viscosity values in the limit of small shear rates are reported for a wide range of Coulomb coupling parameter and screening length. At high shear rates it is demonstrated that this liquid exhibits shear thinning, i.e., the viscosity $\\eta$ diminishes with increasing shear rate. It is expected that two-dimensional dusty plasmas will exhibit this effect.
Abriola, D.; DiGregorio, D.; Testoni, J.E.; Etchegoyen, A.; Etchegoyen, M.C.; Fernandez Niello, J.O.; Ferrero, A.M.J.; Gil, S.; Macchiavelli, A.O.; Pacheco, A.J.; and others
1989-02-01
Angular distributions for elastic and inelastic scattering of /sup 16/O+/sup 144/Sm have been measured at bombarding energies E = 69.2 and 72.3 MeV. Excitation functions were measured between E = 61 and 76.3 MeV at backward angles. The present elastic scattering data plus existing fusion data were adjusted with both energy-independent and energy-dependent optical-model potentials. The energy dependence appears to be consistent with the dispersion relations which correlate the real and imaginary components of the potentials. The potentials behave similarly when coupling to inelastic channels is considered.
NASA Astrophysics Data System (ADS)
Dehesa, J. S.; Yáñez, R. J.; Aptekarev, A. I.; Buyarov, V.
1998-06-01
The information entropies of the two-dimensional harmonic oscillator, V(x,y)=1/2?(x2+y2), and the one-dimensional hydrogen atom, V(x)=-1/|x|, can be expressed by means of some entropy integrals of Laguerre polynomials whose values have not yet been analytically determined. Here, we first study the asymptotical behavior of these integrals in detail by extensive use of strong asymptotics of Laguerre polynomials. Then, this result (which is also important by itself in a context of both approximation theory and potential theory) is employed to analyze the information entropies of the aforementioned quantum-mechanical potentials for the very excited states in both position and momentum spaces. It is observed, in particular, that the sum of position and momentum entropies has a logarithmic growth with respect to the main quantum number which characterizes the corresponding physical state. Finally, the rate of convergence of the entropies is numerically examined.
Zhang, Yubo; Wang, Youwei; Xi, Lili; Qiu, Ruihao; Shi, Xun; Zhang, Peihong E-mail: pzhang3@buffalo.edu; Beijing Computational Science Research Center, Beijing 100084 ; Zhang, Wenqing E-mail: pzhang3@buffalo.edu; School of Chemistry and Chemical Engineering, and Sate Key Laboratory of Coordination Chemistry, Nanjing University, Jiangsu 210093
2014-02-21
The traditional photon absorbers Cu{sub 2?x}X (X = S, Se, and Te) have regained significant research attention in the search of earth-abundant photovoltaic materials. These moderate- and narrow-gap materials have also been shown to exhibit excellent thermoelectric properties recently. However, semimetallic band structures with inverted band orderings are predicted for antifluorite structure Cu{sub 2}X using density functional theory with the local density approximation or the generalized gradient approximation. We find that semiconducting band structures and normal band orderings can be obtained using the modified Becke-Johnson potential plus an on-site Coulomb U (the mBJ+U approach), which is consistent with our earlier finding for diamond-like Cu-based multinary semiconductors [Y. Zhang, J. Zhang, W. Gao, T. A. Abtew, Y. Wang, P. Zhang, and W. Zhang, J. Chem. Phys. 139, 184706 (2013)]. The trend of the chemical bonding of Cu{sub 2}X is analyzed, which shows that the positions of the valence band maximum and conduction band minimum are strongly affected by the inter-site pd and intra-site sp hybridizations, respectively. The calculated gaps of Cu{sub 2}S and Cu{sub 2}Se still seem to be underestimated compared with experimental results. We also discuss the effects of different structural phases and Cu disordering and deficiency on the bandgaps of these materials.
Voicu Dolocan
2015-10-18
By using a Coulomb potential modified by the interaction between the magnetic moments of the electron and proton, we have calculated the energy levels of a hydrogen atom. We have obtained fine structure, hyperfine structure and the Lamb shift. All these are obtained from a simple formula which is a direct solution of the Schroedinger equation. The obtained results are in a good agreement with experimental data. For example, the hyperfine splitting between the energy levels of the states 1S1/2,1 and 1S1/2,0 is of the order of 5.6x10^(-6) eV, which is the source of the famous "21 cm line" which is strongly useful to radio astronomers for tracking hydrogen in the interstellar medium of galaxies. The energy of the states nP1/2 is lower than those of the states nS1/2 (Lamb shift), because in the first case the interaction between the magnetic moments of the proton and electron spins is diminished by the spin-orbit coupling.
Coulomb double helical structure
NASA Astrophysics Data System (ADS)
Kamimura, Tetsuo; Ishihara, Osamu
2012-01-01
Structures of Coulomb clusters formed by dust particles in a plasma are studied by numerical simulation. Our study reveals the presence of various types of self-organized structures of a cluster confined in a prolate spheroidal electrostatic potential. The stable configurations depend on a prolateness parameter for the confining potential as well as on the number of dust particles in a cluster. One-dimensional string, two-dimensional zigzag structure and three-dimensional double helical structure are found as a result of the transition controlled by the prolateness parameter. The formation of stable double helical structures resulted from the transition associated with the instability of angular perturbations on double strings. Analytical perturbation study supports the findings of numerical simulations.
Entropic Corrections to Coulomb's Law
S. H. Hendi; A. Sheykhi
2011-10-17
Two well-known quantum corrections to the area law have been introduced in the literatures, namely, logarithmic and power-law corrections. Logarithmic corrections, arises from loop quantum gravity due to thermal equilibrium fluctuations and quantum fluctuations, while, power-law correction appears in dealing with the entanglement of quantum fields in and out the horizon. Inspired by Verlinde's argument on the entropic force, and assuming the quantum corrected relation for the entropy, we propose the entropic origin for the Coulomb's law in this note. Also we investigate the Uehling potential as a radiative correction to Coulomb potential in 1-loop order and show that for some value of distance the entropic corrections of the Coulomb's law is compatible with the vacuum-polarization correction in QED. So, we derive modified Coulomb's law as well as the entropy corrected Poisson's equation which governing the evolution of the scalar potential $\\phi$. Our study further supports the unification of gravity and electromagnetic interactions based on the holographic principle.
Holomorphic Yukawa Couplings in Heterotic String Theory
Blesneag, Stefan; Candelas, Philip; Lukas, Andre
2015-01-01
We develop techniques, based on differential geometry, to compute holomorphic Yukawa couplings for heterotic line bundle models on Calabi-Yau manifolds defined as complete intersections in projective spaces. It is shown explicitly how these techniques relate to algebraic methods for computing holomorphic Yukawa couplings. We apply our methods to various examples and evaluate the holomorphic Yukawa couplings explicitly as functions of the complex structure moduli. It is shown that the rank of the Yukawa matrix can decrease at specific loci in complex structure moduli space. In particular, we compute the up Yukawa coupling and the singlet-Higgs-lepton trilinear coupling in the heterotic standard model described in arXiv:1404.2767
Numerical approach to Coulomb gauge QCD
Matevosyan, Hrayr H.; Szczepaniak, Adam P.; Bowman, Patrick O.
2008-07-01
We calculate the ghost two-point function in Coulomb gauge QCD with a simple model vacuum gluon wave function using Monte Carlo integration. This approach extends the previous analytic studies of the ghost propagator with this ansatz, where a ladder-rainbow expansion was unavoidable for calculating the path integral over gluon field configurations. The new approach allows us to study the possible critical behavior of the coupling constant, as well as the Coulomb potential derived from the ghost dressing function. We demonstrate that IR enhancement of the ghost correlator or Coulomb form factor fails to quantitatively reproduce confinement using Gaussian vacuum wave functional.
Diffusion in Coulomb crystals.
Hughto, J; Schneider, A S; Horowitz, C J; Berry, D K
2011-07-01
Diffusion in Coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants D from molecular dynamics simulations. We find that D for Coulomb crystals with relatively soft-core 1/r interactions may be larger than D for Lennard-Jones or other solids with harder-core interactions. Diffusion, for simulations of nearly perfect body-centered-cubic lattices, involves the exchange of ions in ringlike configurations. Here ions "hop" in unison without the formation of long lived vacancies. Diffusion, for imperfect crystals, involves the motion of defects. Finally, we find that diffusion, for an amorphous system rapidly quenched from Coulomb parameter ?=175 to Coulomb parameters up to ?=1750, is fast enough that the system starts to crystalize during long simulation runs. These results strongly suggest that Coulomb solids in cold white dwarf stars, and the crust of neutron stars, will be crystalline and not amorphous. PMID:21867316
J. Hughto; A. S. Schneider; C. J. Horowitz; D. K. Berry
2011-06-07
Diffusion in coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants $D$ from molecular dynamics simulations. We find that $D$ for coulomb crystals with relatively soft-core $1/r$ interactions may be larger than $D$ for Lennard-Jones or other solids with harder-core interactions. Diffusion, for simulations of nearly perfect body-centered-cubic lattices, involves the exchange of ions in ring-like configurations. Here ions "hop" in unison without the formation of long lived vacancies. Diffusion, for imperfect crystals, involves the motion of defects. Finally, we find that diffusion, for an amorphous system rapidly quenched from coulomb parameter $\\Gamma=175$ to coulomb parameters up to $\\Gamma=1750$, is fast enough so that the system starts to crystallize during long simulation runs. These results strongly suggest that coulomb solids in cold white dwarf stars, and the crust of neutron stars, will be crystalline and not amorphous.
Hughto, J.; Schneider, A. S.; Horowitz, C. J.; Berry, D. K.
2011-07-15
Diffusion in Coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants D from molecular dynamics simulations. We find that D for Coulomb crystals with relatively soft-core 1/r interactions may be larger than D for Lennard-Jones or other solids with harder-core interactions. Diffusion, for simulations of nearly perfect body-centered-cubic lattices, involves the exchange of ions in ringlike configurations. Here ions ''hop'' in unison without the formation of long lived vacancies. Diffusion, for imperfect crystals, involves the motion of defects. Finally, we find that diffusion, for an amorphous system rapidly quenched from Coulomb parameter {Gamma}=175 to Coulomb parameters up to {Gamma}=1750, is fast enough that the system starts to crystalize during long simulation runs. These results strongly suggest that Coulomb solids in cold white dwarf stars, and the crust of neutron stars, will be crystalline and not amorphous.
The Legacies of Yukawa and His Disciples
NASA Astrophysics Data System (ADS)
Nambu, Yoichiro
2008-06-01
I review and discuss the historical roles Hideki Yukawa and his disciples, Shoichi Sakata in particular, played in developing what we now call particle physics, including their personal and cultural aspects.
Resolutions of the Coulomb Operator
NASA Astrophysics Data System (ADS)
Gill, Peter
2007-03-01
The ``Resolution of the Identity Operator'' I ?| ?n>=
Indirect handle on the down-quark Yukawa coupling.
Goertz, Florian
2014-12-31
To measure the Yukawa couplings of the up and down quarks, Yu,d, seems to be far beyond the capabilities of current and (near) future experiments in particle physics. By performing a general analysis of the potential misalignment between quark masses and Yukawa couplings, we derive predictions for the magnitude of induced flavor-changing neutral currents (FCNCs), depending on the shift in the physical Yukawa coupling of first-generation quarks. We find that a change of more than 50% in Yd would generically result in ds transitions in conflict with kaon physics. This could already be seen as evidence for a nonvanishing direct coupling of the down quark to the newly discovered Higgs boson. The nonobservation of certain--already well-constrained--processes is thus turned into a powerful indirect measure of otherwise basically unaccessible physical parameters of the effective standard model. Similarly, improvements in limits on FCNCs in the up-type quark sector can lead to valuable information on Yu. PMID:25615309
Phase behavior of the modified-Yukawa fluid and its sticky limit
NASA Astrophysics Data System (ADS)
Schöll-Paschinger, Elisabeth; Valadez-Pérez, Néstor E.; Benavides, Ana L.; Castañeda-Priego, Ramón
2013-11-01
Simple model systems with short-range attractive potentials have turned out to play a crucial role in determining theoretically the phase behavior of proteins or colloids. However, as pointed out by D. Gazzillo [J. Chem. Phys. 134, 124504 (2011)], one of these widely used model potentials, namely, the attractive hard-core Yukawa potential, shows an unphysical behavior when one approaches its sticky limit, since the second virial coefficient is diverging. However, it is exactly this second virial coefficient that is typically used to depict the experimental phase diagram for a large variety of complex fluids and that, in addition, plays an important role in the Noro-Frenkel scaling law [J. Chem. Phys. 113, 2941 (2000)], which is thus not applicable to the Yukawa fluid. To overcome this deficiency of the attractive Yukawa potential, D. Gazzillo has proposed the so-called modified hard-core attractive Yukawa fluid, which allows one to correctly obtain the second and third virial coefficients of adhesive hard-spheres starting from a system with an attractive logarithmic Yukawa-like interaction. In this work we present liquid-vapor coexistence curves for this system and investigate its behavior close to the sticky limit. Results have been obtained with the self-consistent Ornstein-Zernike approximation (SCOZA) for values of the reduced inverse screening length parameter up to 18. The accuracy of SCOZA has been assessed by comparison with Monte Carlo simulations.
Phase behavior of the modified-Yukawa fluid and its sticky limit.
Schöll-Paschinger, Elisabeth; Valadez-Pérez, Néstor E; Benavides, Ana L; Castañeda-Priego, Ramón
2013-11-14
Simple model systems with short-range attractive potentials have turned out to play a crucial role in determining theoretically the phase behavior of proteins or colloids. However, as pointed out by D. Gazzillo [J. Chem. Phys. 134, 124504 (2011)], one of these widely used model potentials, namely, the attractive hard-core Yukawa potential, shows an unphysical behavior when one approaches its sticky limit, since the second virial coefficient is diverging. However, it is exactly this second virial coefficient that is typically used to depict the experimental phase diagram for a large variety of complex fluids and that, in addition, plays an important role in the Noro-Frenkel scaling law [J. Chem. Phys. 113, 2941 (2000)], which is thus not applicable to the Yukawa fluid. To overcome this deficiency of the attractive Yukawa potential, D. Gazzillo has proposed the so-called modified hard-core attractive Yukawa fluid, which allows one to correctly obtain the second and third virial coefficients of adhesive hard-spheres starting from a system with an attractive logarithmic Yukawa-like interaction. In this work we present liquid-vapor coexistence curves for this system and investigate its behavior close to the sticky limit. Results have been obtained with the self-consistent Ornstein-Zernike approximation (SCOZA) for values of the reduced inverse screening length parameter up to 18. The accuracy of SCOZA has been assessed by comparison with Monte Carlo simulations. PMID:24320299
Completeness of the Coulomb scattering wave functions
A. M. Mukhamedzhanov; M. Akin
2006-02-01
Completeness of the eigenfunctions of a self-adjoint Hamiltonian, which is the basic ingredient of quantum mechanics, plays an important role in nuclear reaction and nuclear structure theory. However, until now, there was no a formal proof of the completeness of the eigenfunctions of the two-body Hamiltonian with the Coulomb interaction. Here we present the first formal proof of the completeness of the two-body Coulomb scattering wave functions for repulsive unscreened Coulomb potential. To prove the completeness we use the Newton's method [R. Newton, J. Math Phys., 1, 319 (1960)]. The proof allows us to claim that the eigenfunctions of the two-body Hamiltonian with the potential given by the sum of the repulsive Coulomb plus short-range (nuclear) potentials also form a complete set. It also allows one to extend the Berggren's approach of modification of the complete set of the eigenfunctions by including the resonances for charged particles. We also demonstrate that the resonant Gamow functions with the Coulomb tail can be regularized using Zel'dovich's regularization method.
Proton-proton scattering without Coulomb force renormalization
R. Skibinski; J. Golak; H. Witala; W. Glockle
2009-03-06
We demonstrate numerically that proton-proton (pp) scattering observables can be determined directly by standard short range methods using a screened pp Coulomb force without renormalization. In examples the appropriate screening radii are given. We also numerically investigate solutions of the 3-dimensional Lippmann-Schwinger (LS) equation for a screened Coulomb potential alone in the limit of large screening radii and confirm analytically predicted properties for off-shell, half-shell and on-shell Coulomb t-matrices. These 3-dimensional solutions will form a basis for a novel approach to include the pp Coulomb interaction into the 3N Faddeev framework.
Invariants in the Yukawa system's thermodynamic phase diagram
NASA Astrophysics Data System (ADS)
Veldhorst, Arno A.; Schrøder, Thomas B.; Dyre, Jeppe C.
2015-07-01
This paper shows that several known properties of the Yukawa system can be derived from the isomorph theory, which applies to any system that has strong correlations between its virial and potential-energy equilibrium fluctuations. Such "Roskilde-simple" systems have a simplified thermodynamic phase diagram deriving from the fact that they have curves (isomorphs) along which structure and dynamics in reduced units are invariant to a good approximation. We show that the Yukawa system has strong virial potential-energy correlations and identify its isomorphs by two different methods. One method, the so-called direct isomorph check, identifies isomorphs numerically from jumps of relatively small density changes (here 10%). The second method identifies isomorphs analytically from the pair potential. The curves obtained by the two methods are close to each other; these curves are confirmed to be isomorphs by demonstrating the invariance of the radial distribution function, the static structure factor, the mean-square displacement as a function of time, and the incoherent intermediate scattering function. Since the melting line is predicted to be an isomorph, the theory provides a derivation of a known approximate analytical expression for this line in the temperature-density phase diagram. The paper's results give the first demonstration that the isomorph theory can be applied to systems like dense colloidal suspensions and strongly coupled dusty plasmas.
Invariants in the Yukawa system's thermodynamic phase diagram
Arno A. Veldhorst; Thomas B. Schrøder; Jeppe C. Dyre
2015-06-30
This paper shows that several known properties of the Yukawa system can be derived from the isomorph theory, which applies to any system that has strong correlations between its virial and potential-energy equilibrium fluctuations. Such "Roskilde-simple" systems have a simplified thermodynamic phase diagram deriving from the fact that they have curves (isomorphs) along which structure and dynamics in reduced units are invariant to a good approximation. We show that the Yukawa system has strong virial potential-energy correlations and identify its isomorphs by two different methods. One method, the so-called direct isomorph check, identifies isomorphs numerically from jumps of relatively small density changes (here 10%). The second method identifies isomorphs analytically from the pair potential. The curves obtained by the two methods are close to each other; these curves are confirmed to be isomorphs by demonstrating the invariance of the radial distribution function, the static structure factor, the mean-square displacement as a function of time, and the incoherent intermediate scattering function. Since the melting line is predicted to be an isomorph, the theory provides a derivation of a known approximate analytical expression for this line in the temperature-density phase diagram. The paper's results give the first demonstration that the isomorph theory can be applied to systems like dense colloidal suspensions and strongly coupled dusty plasmas.
YUKAWA's PION , LOW-ENERGY QCD and NUCLEAR CHIRAL DYNAMICS
Weise, Wolfram
YUKAWA's PION , LOW-ENERGY QCD and NUCLEAR CHIRAL DYNAMICS Wolfram Weise Yukawa - Tomonaga Low-Energy QCD and Chiral Symmetry: Pion in Lattice QCD Chiral Effective FieldTheory Yukawa's Legacy VI tl. --, #12;Eil On the Tntera,cti,on of Ble,mentar.tl Pctt ti,cles. I. By Hideki Yurewe. (Read Nov
Constraining the range of Yukawa gravity interaction from S2 star orbits
Borka, D.; Jovanovi?, V. Borka; Jovanovi?, P.; Zakharov, A.F. E-mail: pjovanovic@aob.rs E-mail: zakharov@itep.ru
2013-11-01
We consider possible signatures for Yukawa gravity within the Galactic Central Parsec, based on our analysis of the S2 star orbital precession around the massive compact dark object at the Galactic Centre, and on the comparisons between the simulated orbits in Yukawa gravity and two independent sets of observations. Our simulations resulted in strong constraints on the range of Yukawa interaction ? and showed that its most probable value in the case of S2 star is around 5000 - 7000 AU. At the same time, we were not able to obtain reliable constrains on the universal constant ? of Yukawa gravity, because the current observations of S2 star indicated that it may be highly correlated with parameter ? in the range (0 < ? < 1). For ? > 2 they are not correlated. However, the same universal constant which was successfully applied to clusters of galaxies and rotation curves of spiral galaxies (? = 1/3) also gives a satisfactory agreement with the observed orbital precession of the S2 star, and in that case the most probable value for the scale parameter is ? ? 3000±1500 AU. Also, the Yukawa gravity potential induces precession of S2 star orbit in the same direction as General Relativity for ? > 0 and for ? < ?1, and in the opposite direction for ?1 < ? < 0. The future observations with advanced facilities, such as GRAVITY or/and European Extremely Large Telescope, are needed in order to verify these claims.
YITP Annual Report Yukawa Institute For
Shimizu, Akira
played by the institute was to provide a fo- rum for physicists on various problems at the forefront with others. With this spirit and system, YITP has been successfully playing important roles in creating. For instance, we have changed Yukawa International Seminar to hold every year from every two years. The YKIS
2012-01-01
crystal, Yukawa crystal, elastic moduli, shear modulus. Shear modulus of a body-centered cubic CoulombContrib. Plasma Phys. 52, No. 2, 157 160 (2012) / DOI 10.1002/ctpp.201100073 Shear Modulus agree well with previous Monte Carlo simulations. In this case, the shear modulus is given by a sum
G. Baym; P. Braun-Munzinger
1996-06-27
We discuss the elementary physics of the final state Coulomb interactions in Hanbury-Brown Twiss interferometry, showing -- with explicit comparison to E877 data for $\\pi^+\\pi^-$ and $\\pi^\\pm p$ -- that the Coulomb corrections in the pair correlation function can be well understood in terms of simple classical physics. We connect the classical picture with descriptions in terms of Coulomb wave functions, and investigate the influence of the ``central'' Coulomb potential on the pair correlation function.
Relative partition function of Coulomb plus delta interaction
Sergio Albeverio; Claudio Cacciapuoti; Mauro Spreafico
2015-10-16
The relative partition function and the relative zeta function of the perturbation of the Laplace operator by a Coulomb potential plus a point interaction centered in the origin is discussed. Applications to the study of the Casimir effect are indicated.
Mapping Dirac quasiparticles near a single Coulomb impurity on graphene
Wang, Yang
The response of Dirac fermions to a Coulomb potential is predicted to differ significantly from how non-relativistic electrons behave in traditional atomic and impurity systems. Surprisingly, many key theoretical predictions ...
Yukawa Unification Predictions with Effective ``Mirage'' Mediation
NASA Astrophysics Data System (ADS)
Anandakrishnan, Archana; Raby, Stuart
2013-11-01
In this Letter we analyze the consequences, for the LHC, of gauge and third family Yukawa coupling unification with a particular set of boundary conditions defined at the grand unified theory (GUT) scale, which we characterize as effective “mirage” mediation. We perform a global ?2 analysis including the observables MW, MZ, GF, ?em-1, ?s(MZ), Mt, mb(mb), M?, BR(B?Xs?), BR(Bs??+?-), and Mh. The fit is performed in the minimal supersymmetric standard model in terms of 10 GUT scale parameters, while tan?? and ? are fixed at the weak scale. We find good fits to the low energy data and a supersymmetry spectrum which is dramatically different than previously studied in the context of Yukawa unification.
Yukawa unification predictions with effective "mirage" mediation.
Anandakrishnan, Archana; Raby, Stuart
2013-11-22
In this Letter we analyze the consequences, for the LHC, of gauge and third family Yukawa coupling unification with a particular set of boundary conditions defined at the grand unified theory (GUT) scale, which we characterize as effective "mirage" mediation. We perform a global ?2 analysis including the observables M(W), M(Z), G(F), ?(em)(-1), ?(s)(M(Z)), M(t), m(b)(m(b)), M(?), BR(B?X(s)?), BR(B(s)??(+)?(-)), and M(h). The fit is performed in the minimal supersymmetric standard model in terms of 10 GUT scale parameters, while tan? and ? are fixed at the weak scale. We find good fits to the low energy data and a supersymmetry spectrum which is dramatically different than previously studied in the context of Yukawa unification. PMID:24313477
Yukawa Unification Predictions with effective "Mirage" Mediation
Archana Anandakrishnan; Stuart Raby
2013-09-02
In this letter we analyze the consequences, for the LHC, of gauge and third family Yukawa coupling unification with a particular set of boundary conditions defined at the GUT scale, which we characterize as effective "mirage" mediation. We perform a global chi-squared analysis including the observables M_W, M_Z, G_F, alpha_em, alpha_s(M_Z), M_top, m_b(m_b), M_tau, BR(B -> X_s gamma), BR(B_s -> mu^+ mu^-) and M_{h}. The fit is performed in the MSSM in terms of 10 GUT scale parameters, while tanb and mu are fixed at the weak scale. We find good fits to the low energy data and a SUSY spectrum which is dramatically different than previously studied in the context of Yukawa unification.
Yukawa Unification Predictions with effective "Mirage" Mediation
Anandakrishnan, Archana
2013-01-01
In this letter we analyze the consequences, for the LHC, of gauge and third family Yukawa coupling unification with a particular set of boundary conditions defined at the GUT scale, which we characterize as effective "mirage" mediation. We perform a global chi-squared analysis including the observables M_W, M_Z, G_F, alpha_em, alpha_s(M_Z), M_top, m_b(m_b), M_tau, BR(B -> X_s gamma), BR(B_s -> mu^+ mu^-) and M_{h}. The fit is performed in the MSSM in terms of 10 GUT scale parameters, while tanb and mu are fixed at the weak scale. We find good fits to the low energy data and a SUSY spectrum which is dramatically different than previously studied in the context of Yukawa unification.
Remote Spacecraft Attitude Control by Coulomb Charging
NASA Astrophysics Data System (ADS)
Stevenson, Daan
The possibility of inter-spacecraft collisions is a serious concern at Geosynchronous altitudes, where many high-value assets operate in proximity to countless debris objects whose orbits experience no natural means of decay. The ability to rendezvous with these derelict satellites would enable active debris removal by servicing or repositioning missions, but docking procedures are generally inhibited by the large rotational momenta of uncontrolled satellites. Therefore, a contactless means of reducing the rotation rate of objects in the space environment is desired. This dissertation investigates the viability of Coulomb charging to achieve such remote spacecraft attitude control. If a servicing craft imposes absolute electric potentials on a nearby nonspherical debris object, it will impart electrostatic torques that can be used to gradually arrest the object's rotation. In order to simulate the relative motion of charged spacecraft with complex geometries, accurate but rapid knowledge of the Coulomb interactions is required. To this end, a new electrostatic force model called the Multi-Sphere Method (MSM) is developed. All aspects of the Coulomb de-spin concept are extensively analyzed and simulated using a system with simplified geometries and one dimensional rotation. First, appropriate control algorithms are developed to ensure that the nonlinear Coulomb torques arrest the rotation with guaranteed stability. Moreover, the complex interaction of the spacecraft with the plasma environment and charge control beams is modeled to determine what hardware requirements are necessary to achieve the desired electric potential levels. Lastly, the attitude dynamics and feedback control development is validated experimentally using a scaled down terrestrial testbed. High voltage power supplies control the potential on two nearby conductors, a stationary sphere and a freely rotating cylinder. The nonlinear feedback control algorithms developed above are implemented to achieve rotation rate and absolute attitude control. Collectively, these studies decisively validate the feasibility of Coulomb charging for remote spacecraft attitude control.
Coulomb explosion of nitrogen and oxygen molecules through non-Coulombic states.
Wu, Chengyin; Yang, Yudong; Wu, Zhifeng; Chen, Bozhen; Dong, Hua; Liu, Xianrong; Deng, Yongkai; Liu, Hong; Liu, Yunquan; Gong, Qihuang
2011-11-01
We have systematically studied Coulomb explosion of nitrogen and oxygen molecules in intense 8 and 24 fs laser pulses. In the experiment, we explicitly separated all explosion pathways through coincident measurements. The high resolution kinetic energy releases (KERs) and the exotic angular distributions of atomic ions provide direct evidence that Coulomb explosion occurs through non-Coulombic states. In the theory, we calculated dissociation potential energy curves (PECs) of nitrogen and oxygen molecules and their multicharged molecular ions using multiconfiguration second-order perturbation theory. The results indicate that Coulomb potentials are close to the accurate PECs of multicharged molecular ions only when the internuclear distance is larger than 3 Å. In comparison with the experimental observations and the theoretical calculations, we determined the internuclear distance when Coulombic explosion occurs. It is near the equilibrium distance of the neutral molecules in the case of 8 fs laser pulses and expands gradually with the increase of the charge state of the molecular ions in the case of 24 fs laser pulses. PMID:21881654
Coulomb Bound States of Strongly Interacting Photons
NASA Astrophysics Data System (ADS)
Maghrebi, M. F.; Gullans, M. J.; Bienias, P.; Choi, S.; Martin, I.; Firstenberg, O.; Lukin, M. D.; Büchler, H. P.; Gorshkov, A. V.
2015-09-01
We show that two photons coupled to Rydberg states via electromagnetically induced transparency can interact via an effective Coulomb potential. This interaction gives rise to a continuum of two-body bound states. Within the continuum, metastable bound states are distinguished in analogy with quasibound states tunneling through a potential barrier. We find multiple branches of metastable bound states whose energy spectrum is governed by the Coulomb potential, thus obtaining a photonic analogue of the hydrogen atom. Under certain conditions, the wave function resembles that of a diatomic molecule in which the two polaritons are separated by a finite "bond length." These states propagate with a negative group velocity in the medium, allowing for a simple preparation and detection scheme, before they slowly decay to pairs of bound Rydberg atoms.
Phase diagram of the hard-core Yukawa fluid within the integral equation method.
El Mendoub, E B; Wax, J-F; Jakse, N
2006-11-01
In this study, the integral equation method proposed recently by Sarkisov [J. Chem. Phys. 114, 9496 (2001).], which has proved accurate for continuous potentials, is extended successfully to the hard sphere potential plus an attractive Yukawa tail. By comparing the results of thermodynamic properties, including the liquid-vapor phase diagram, with available simulation data, it is found that this method remains reliable for this class of models of interaction often used in colloid science. PMID:17279956
Giant Interatomic Coulombic Decay
NASA Astrophysics Data System (ADS)
Sisourat, Nicolas; Kryzhevoi, Nikolai V.; Koloren?, P?emysl; Scheit, Simona; Cederbaum, Lorenz S.
2012-11-01
On the example of the giant helium dimer, we present an efficient electronic decay process for excited atoms or molecules embedded in a chemical environment, called Interatomic (intermolecular) Coulombic decay (ICD). After simultaneous ionization and excitation of a helium atom within a helium dimer, the excited ion relaxes by ICD to He+(1s) and the neighbor neutral helium is ionized to He+(1s) as well and emits a secondary electron. A short review on ab initio methods developed during the last 10 years to accurately describe ICD is reported. Finally, the main striking results on the helium dimer obtained experimentally and theoretically are summarized.
Polonyi, J.
2008-06-15
The contribution of different modes of the Coulomb field to decoherence and to the dynamical breakdown of the time reversal invariance is calculated in the one-loop approximation for nonrelativistic electron gas. The dominant contribution was found to come from the usual collective modes in the plasma, namely, the zero-sound and the plasmon oscillations. The length scale of the quantum-classical transition is found to be close to the Thomas-Fermi screening length. It is argued that the extension of these modes to the whole Fock space yields optimal pointer states.
F. Caruso; J. Martins; L. D. Perlingeiro; V. Oguri
2015-04-09
The relativistic hydrogen atom in an Euclidean space-time of arbitrary number of space dimensions ($D$) plus one time dimension is revisited. In particular, numerical solutions of the radial Dirac equation for a generalized Coulombian potential proportional to $1/r^{(D-2)}$ are investigated. It is argued that one could not find any physical solution for $D\\geq 4$.
Breakdown of the Yukawa model in de-ionized colloidal suspensions.
Torres, Aldemar; Cuetos, Alejandro; Dijkstra, Marjolein; van Roij, René
2008-03-01
We study effective colloidal interactions in de-ionized colloidal mixtures through sedimentation-diffusion equilibrium. We derive a coarse-grained effective model (EM) and compare its density profiles with those of the computationally much more expensive primitive model (PM) of colloids and counterions in gravity. The EM, which contains not only standard pairwise screened-Coulomb interactions, but also explicit many-body effects by means of a so-called volume term, can quantitatively account for all observed sedimentation phenomena such as lifting of colloids to high altitudes, segregation into layers in mixtures, and floating of heavy colloids on top of lighter ones. Without the volume term there is no quantitative agreement between the PM and EM, even in the present high-temperature limit of interest, showing that de-ionized colloidal suspensions cannot be described by a pairwise Yukawa model. PMID:18517376
Lepton masses and mixing without Yukawa hierarchies
Ponce, William A.; Zapata, Oscar
2006-11-01
We investigate the neutrino masses and mixing pattern in a version of the SU(3){sub c}(multiply-in-circle sign)SU(3){sub L}(multiply-in-circle sign)U(1){sub X} model with one extra exotic charged lepton per family as introduced by Ozer. It is shown that an extended scalar sector, together with a discrete Z{sub 2} symmetry, is able to reproduce a consistent lepton mass spectrum without a hierarchy in the Yukawa coupling constants, the former as a consequence of a carefull balance between one universal see-saw and two radiative mechanisms.
Periodically sheared 2D Yukawa systems
NASA Astrophysics Data System (ADS)
Kovács, Anikó Zsuzsa; Hartmann, Peter; Donkó, Zoltán
2015-10-01
We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.
Exclusive window onto Higgs Yukawa couplings.
Kagan, Alexander L; Perez, Gilad; Petriello, Frank; Soreq, Yotam; Stoynev, Stoyan; Zupan, Jure
2015-03-13
We show that both flavor-conserving and flavor-violating Yukawa couplings of the Higgs boson to first- and second-generation quarks can be probed by measuring rare decays of the form h?MV, where M denotes a vector meson and V indicates either ?, W or Z. We calculate the branching ratios for these processes in both the standard model and its possible extensions. We discuss the experimental prospects for their observation. The possibility of accessing these Higgs couplings appears to be unique to the high-luminosity LHC and future hadron colliders, providing further motivation for those machines. PMID:25815924
Classical and quantum Coulomb crystals
Bonitz, M.; Ludwig, P.; Baumgartner, H.; Henning, C.; Filinov, A.; Block, D.; Arp, O.; Piel, A.; Kaeding, S.; Ivanov, Y.; Melzer, A.; Fehske, H.; Filinov, V.
2008-05-15
Strong correlation effects in classical and quantum plasmas are discussed. In particular, Coulomb (Wigner) crystallization phenomena are reviewed focusing on one-component non-neutral plasmas in traps and on macroscopic two-component neutral plasmas. The conditions for crystal formation in terms of critical values of the coupling parameters and the distance fluctuations and the phase diagram of Coulomb crystals are discussed.
Yukawa Unification and the Superpartner Mass Scale
Elor, Gilly; Pinner, David; Ruderman, Joshua T
2012-01-01
Naturalness in supersymmetry (SUSY) is under siege by increasingly stringent LHC constraints, but natural electroweak symmetry breaking still remains the most powerful motivation for superpartner masses within experimental reach. If naturalness is the wrong criterion then what determines the mass scale of the superpartners? We motivate supersymmetry by (1) gauge coupling unification, (2) dark matter, and (3) precision b-tau Yukawa unification. We show that for an LSP that is a bino-Higgsino admixture, these three requirements lead to an upper-bound on the stop and sbottom masses in the several TeV regime because the threshold correction to the bottom mass at the superpartner scale is required to have a particular size. For tan beta about 50, which is needed for t-b-tau unification, the stops must be lighter than 2.8 TeV when A_t has the opposite sign of the gluino mass, as is favored by renormalization group scaling. For lower values of tan beta, the top and bottom squarks must be even lighter. Yukawa unifica...
The Effects of Static Coulomb Stress Change on Southern California Earthquake Forecasting
NASA Astrophysics Data System (ADS)
Strader, Anne Elizabeth
I investigate how inclusion of static Coulomb stress changes, caused by tectonic loading and previous seismicity, contributes to the effectiveness and reliability of prospective earthquake forecasts. Several studies have shown that positive static Coulomb stress changes are associated with increased seismicity, relative to stress shadows. However, it is difficult to avoid bias when the learning and testing intervals are chosen retrospectively. I hypothesize that earthquake forecasts based on static Coulomb stress fields may improve upon existing earthquake forecasts based on historical seismicity. Within southern California, I have confirmed the aforementioned relationship between earthquake location and Coulomb stress change, but found no identifiable triggering threshold based on static Coulomb stress history at individual earthquake locations. I have also converted static Coulomb stress changes into spatially-varying earthquake rates by optimizing an index function and calculating probabilities of cells containing at least one earthquake based on Coulomb stress ranges. Inclusion of Coulomb stress effects gives an improvement in earthquake forecasts that is significant with 95% confidence, compared to smoothed seismicity null forecasts. Because of large uncertainties in Coulomb stress calculations near faults (and aftershock distributions), I combine static Coulomb stress and smoothed seismicity into a hybrid earthquake forecast. Evaluating such forecasts against those in which only Coulomb stress or smoothed seismicity determines earthquake rates indicates that Coulomb stress is more effective in the far field, whereas statistical seismology outperforms Coulomb stress near faults. Additionally, I test effects of receiver plane orientation, stress type (normal and shear components), and declustering receiver earthquakes. While static Coulomb stress shows significant potential in a prospective earthquake forecast, simplifying assumptions compromise its effectiveness. For example, we assume that crustal material within the study region is isotropic and homogeneous and purely elastic, and that pore fluid pressure variations do not significantly affect the static Coulomb stress field. Such assumptions require further research in order to detect direct earthquake triggering mechanisms.
A parameterized model for Coulomb barrier height
Deepak Kumar Swami; Prashant Sharma; Tapan Nandi
2015-10-15
Coulomb barrier height is a basic parameter to describing the nuclear reactions. Recently it is found that ions produce from nuclear reactions can be used to study electron loss and capture processes. Hence determining the Coulomb barrier becomes important in both nuclear and atomic physics. The different models depend on the nucleus-nucleus potential chosen or parameters used to calculate the barrier heights. In this work we plan to develop a parameterized formula from experimental results obtained from quasi elastic scattering. Since quasi elastic data spread over Z1Z2=64 to Z1Z2=2460, the formula is expected to work in the range of low Z1Z2 to high Z1Z2, where Z1, Z2 are the atomic number of the projectile and the target, respectively.
Anomalous Coulomb oscillation in crossed carbon nanotubes
NASA Astrophysics Data System (ADS)
Baek, Seung Jae; Lee, Dongsu; Park, Seung Joo; Park, Yung Woo; Svensson, Johannes; Jonson, Mats; Campbell, Eleanor E. B.
2008-03-01
Single-walled carbon nanotube (SWCNT) crossed junctions separated by an insulating layer were fabricated to investigate the double quantum dot modulated by a single gate (DQD-sG). Anomalous Coulomb oscillations were observed on the lower CNT at low temperature, where the behavior was interpreted by the concept of a double quantum dot (DQD) system http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id =APPLAB000089000023233107000001&idtype=cvips&gifs=yes [1]. To understand it more clearly, we have intentionally fabricated crossed CNTs without oxide layer in between. The observed anomalous Coulomb oscillations indicate that the contact resistance between the two tubes becomes a potential barrier splitting the initial single QD into the DQD, and the back-gate modulates the energy levels of the DQD.
Coulomb crystallization of highly charged ions.
Schmöger, L; Versolato, O O; Schwarz, M; Kohnen, M; Windberger, A; Piest, B; Feuchtenbeiner, S; Pedregosa-Gutierrez, J; Leopold, T; Micke, P; Hansen, A K; Baumann, T M; Drewsen, M; Ullrich, J; Schmidt, P O; López-Urrutia, J R Crespo
2015-03-13
Control over the motional degrees of freedom of atoms, ions, and molecules in a field-free environment enables unrivalled measurement accuracies but has yet to be applied to highly charged ions (HCIs), which are of particular interest to future atomic clock designs and searches for physics beyond the Standard Model. Here, we report on the Coulomb crystallization of HCIs (specifically (40)Ar(13+)) produced in an electron beam ion trap and retrapped in a cryogenic linear radiofrequency trap by means of sympathetic motional cooling through Coulomb interaction with a directly laser-cooled ensemble of Be(+) ions. We also demonstrate cooling of a single Ar(13+) ion by a single Be(+) ion-the prerequisite for quantum logic spectroscopy with a potential 10(-19) accuracy level. Achieving a seven-orders-of-magnitude decrease in HCI temperature starting at megakelvin down to the millikelvin range removes the major obstacle for HCI investigation with high-precision laser spectroscopy. PMID:25766230
Coulomb Drag Mechanisms in Graphene
Abanin, Dmitry A.
Recent measurements revealed an anomalous Coulomb drag in graphene, hinting at new physics at charge neutrality. The anomalous drag is explained by a new mechanism based on energy transport, which involves interlayer energy ...
Determination of the dynamically generated Yukawa coupling in supersymmetric QCD
Kitazawa, N
2000-01-01
The strength of the Yukawa coupling among composite fields is calculated. The system of N=1 supersymmetric SU(2) gauge theory with three flavors is considered as an example. The strength is important, since such dynamically generated Yukawa interactions are identified with the Yukawa interactions in the standard model in some composite models. We use the techniques of "integrating in" the gluino-gluino bound state in the low energy effective theory and the instanton calculation and Shifman-Vainshtein-Zakharov sum rule (QCD sum rule) in the fundamental theory. The obtained value of the Yukawa coupling is of the order of unity, which is different from the result of the naive dimensional analysis: 4 \\pi \\sim 10. The method which is developed in this paper can be applied to the large class of supersymmetric gauge theories.
Thermodynamics of Yukawa systems and sound velocity in dusty plasmas
NASA Astrophysics Data System (ADS)
Khrapak, S. A.
2016-01-01
The simple practical approaches to estimate thermodynamic properties of three-dimensional Yukawa systems across coupling regimes (in fluid and solid phases) are summarized. These approaches demonstrate very good accuracy when compared with the results of direct numerical simulations. To demonstrate possible applications, the sound velocity in a strongly coupled dusty plasma is evaluated by combining the conventional fluid description of multi-component plasma with the appropriate equation of state of Yukawa fluids. Limitations of the proposed approaches are briefly discussed.
Action principle for Coulomb collisions in plasmas
Hirvijoki, Eero
2015-01-01
In this letter we derive an action principle for Coulomb collisions in plasmas. Although no natural Lagrangian exists for the Landau-Fokker-Planck equation, an Eulerian variational formulation is found considering the system of partial differential equations that couple the distribution function and the Rosenbluth potentials. Exact conservation laws are derived after generalizing the energy-momentum stress tensor for second order Lagrangians and, in the case of a test-particle population in a given plasma background, the action principle is shown to correspond to the Langevin equation for individual particles. Being suitable for discretization, the presented action allows construction of variational integrators. Numerical implementation is left for a future study.
Coulomb confinement from the Yang-Mills vacuum state in 2+1 dimensions
Greensite, Jeff; Olejnik, Stefan
2010-04-01
The Coulomb-gauge ghost propagator and the color-Coulomb potential are computed in an ensemble of configurations derived from our recently proposed Yang-Mills vacuum wave functional in 2+1 dimensions. The results are compared to the corresponding values obtained by standard Monte Carlo simulations in three Euclidean dimensions. The agreement is quite striking for the Coulomb-gauge ghost propagator. The color-Coulomb potential rises linearly at large distances, but its determination suffers from rather large statistical fluctuations, due to configurations with very low values of {mu}{sub 0}, the lowest eigenvalue of the Coulomb-gauge Faddeev-Popov operator. However, if one imposes cuts on the data, effectively leaving out configurations with very low {mu}{sub 0}, the agreement of the potential in both sets of configurations is again satisfactory, although the error bars grow systematically as the cutoff is eliminated.
Adam P. Szczepaniak; Eric S. Swanson
2000-12-12
Here we will discuss how the nonabelian Coulomb kernel exhibits confinement already at the mean field level. In the heavy quark limit residual interactions between heavy quarks and transverse gluons are spin dependent i.e., relativistic and can be calculated using the Foldy-Wouthuysen transformation. This makes the Coulomb gauge suitable for studying the nonrelativistic limit. Finally it is possible to use standard mean field techniques to define quasiparticle excitations, which, as we discuss below, have similar properties to what is usually assumed about constituent quarks in the light quark sector.
Coulomb energy of axially deformed nucleus
Ning Wang; Xuexin Yu; Min Liu
2010-05-17
We previously proposed a formula for calculating the Coulomb energy of spherical nucleus with Wood-Saxon charge distribution. In this work, the analytical formula is extended for description of the Coulomb energy of nucleus with beta2 deformation.
Coulomb gauge approach for charmonium meson and hybrid radiative transitions
Gou, Peng; Yepez-Martínez, Tochtli; Szczepaniak, Adam P.
2015-01-22
We consider the lowest order interaction of the Foldy-Wouthuysen QED and QCD Hamiltonian in the Coulomb gauge approach, to describe radiative transitions between conventional and hybrids charmonium mesons. The results are compared to potential quark models and lattices calculations.
Coulomb scattering for scalar field in Scr\\" odinger picture
Crucean Cosmin; Racoceanu Radu; Pop Adrian
2008-04-11
The scattering of a charged scalar field on Coulomb potential on de Sitter space-time is studied using the solution of the free Klein-Gordon equation. We find that the scattering amplitude is independent of the choice of the picture and in addition the total energy is conserved in the scattering process.
Coulomb vs. physical string tension on the lattice
G. Burgio; M. Quandt; H. Reinhardt; H. Vogt
2015-08-20
From continuum studies it is known that the Coulomb string tension $\\sigma_C$ gives an upper bound for the physical (Wilson) string tension $\\sigma_W$ [D. Zwanziger, Phys. Rev. Lett. 90, 102001 (2003)]. How does however such relationship translate to the lattice? In this paper we give evidence that there, while the two string tensions are related at zero temperature, they decouple at finite temperature. More precisely, we show that on the lattice the Coulomb gauge confinement scenario is always tied to the spatial string tension, which is known to survive the deconfinement phase transition and to cause screening effects in the quark-gluon plasma. Our analysis is based on the identification and elimination of center vortices which allows to control the physical string tension and study its effect on the Coulomb gauge observables. We also show how alternative definitions of the Coulomb potential may sense the deconfinement transition; however a true static Coulomb gauge order parameter for the phase transition is still elusive on the lattice.
Near-prospective test of Coulomb stress triggering
NASA Astrophysics Data System (ADS)
Strader, Anne; Jackson, David D.
2014-04-01
Numerous studies retrospectively observed a strong association between earthquake location and increased static Coulomb stress. In addition to confirming these results for southern California seismicity, we observed prospective forecasting potential in static stress evolution. With 141 seismic and 98 aseismic stress sources, we considered alternate choices of stress components and receiver fault orientations, examined the effect of Coulomb triggering on earthquake magnitude, calculated stress histories for receiver quakes to see if some occurred after their stress had peaked, examined whether stress changes from the Hector Mine earthquake alone changed the earthquake rate as expected, and estimated the conditional distribution of earthquake occurrence given resolved Coulomb stress change. We found that with 95% confidence, M ? 2.8 receiver earthquakes nucleate in areas of shear or Coulomb stress change increase. On average, 59% of earthquakes occurred within stress-enhanced zones, regardless of the choice of rupture plane or type of stress change. The 1999 Hector Mine, California, earthquake increased the seismicity in regions of positive and negative stress change but more so in the positive regions. Earthquakes frequently occur after their calculated peak stress has occurred, indicating that elastic calculations do not tell the whole story. We found no significant evidence that stress change affects the magnitude of receiver quakes. Thus, instantaneous Coulomb and shear stress change apparently influence the locations but not the magnitudes of future earthquakes.
Signatures of baryon-nonconserving Yukawa couplings in a supersymmetric theory
NASA Astrophysics Data System (ADS)
Bastero-Gil, Mar; Brahmachari, Biswajoy
1997-12-01
Renormalization effects of large baryon-nonconserving Yukawa couplings ?''ijkDiDjUk¯ lower the right-handed squark masses keeping the left-handed squark masses virtually untouched at the lowest order. At low energy they enhance the mass splitting between left- and right-handed squarks of the same generation as well as intergenerational mass splitting among squarks, potentially detectable in future colliders or in rare decays. The predicted mass of the lightest top squark becomes lower than the experimental bound for larger ranges of parameter space than that of the baryon-conserving case, hence, further constraining the parameter space of a supersymmetric theory when baryon violation is included.
Vapor-liquid surface tension of strong short-range Yukawa fluid
G. Odriozola; M. Bárcenas; P. Orea
2011-04-07
The thermodynamic properties of strong short-range attractive Yukawa fluids, k=10, 9, 8, and 7, are determined by combining the slab technique with the standard and the replica exchange Monte Carlo (REMC) methods. A good agreement was found among the coexistence curves of these systems calculated by REMC and those previously reported in the literature. However, REMC allows exploring the coexistence at lower temperatures, where dynamics turns glassy. To obtain the surface tension we employed, for both methods, a procedure that yields the pressure tensor components for discontinuous potentials. The surface tension results obtained by the standard MC and REMC techniques are in good agreement.
Numerical studies of the melting transition in 2D Yukawa systems
Hartmann, P.; Donko, Z.; Kalman, G. J.
2008-09-07
We present the latest results of our systematic studies of the solid--liquid phase transition in 2D classical many-particle systems interacting with the Yukawa potential. Our previous work is extended by applying the molecular dynamic simulations to systems with up to 1.6 million particles in the computational box (for {kappa} = 2 case). Equilibrium simulations are performed for different coupling parameters in the vicinity of the expected melting transition ({gamma}{sub m}{sup {kappa}}{sup ={sup 2}}{approx_equal}415) and a wide range of observables are averaged over uncorrelated samples of the micro-canonical ensemble generated by the simulations.
Narojczyk, Jakub W; Wojciechowski, K W; Tretiakov, K V
2015-01-01
Monte Carlo simulations of mono-- and polydisperse two--dimensional crystals are reported. The particles in the studied system, interacting through hard--core repulsive Yukawa potential, form a solid phase of hexagonal lattice. The elastic properties of crystalline Yukawa systems are determined in the $NpT$ ensemble with variable shape of the periodic box. Effects of the Debye screening length ($\\kappa^{-1}$), contact value of the potential ($\\epsilon$), and the size polydispersity of particles on elastic properties of the system are studied. The simulations show that the polydispersity of particles strongly influences the elastic properties of the studied system, especially on the shear modulus. It is also found that the elastic moduli increase with density and their growth rate depends on the screening length. Shorter screening length leads to faster increase of elastic moduli with density and decrease of the Poisson's ratio. In contrast to its three-dimensional version, the studied system is non-auxetic, i...
Fluid approach to evaluate sound velocity in Yukawa systems (complex plasmas)
Sergey Khrapak; Hubertus Thomas
2015-03-02
The conventional fluid description of multi-component plasma, supplemented by an appropriate equation of state for the macroparticle component, is used to evaluate the longitudinal sound velocity of Yukawa fluids. The obtained results are in very good agreement with those obtained earlier employing the quasi-localized charge approximation and molecular dynamics simulations in a rather broad parameter regime. Thus, a simple yet accurate tool to estimate the sound velocity across coupling regimes is proposed, which can be particularly helpful in estimating the dust-acoustic velocity in strongly coupled dusty (complex) plasmas. It is shown that, within the present approach, the sound velocity is completely determined by particle-particle correlations and the neutralizing medium (plasma), apart from providing screening of the Coulomb interaction, has no other effect on the sound propagation. The ratio of the actual sound velocity to its "ideal gas" (weak coupling) scale only weakly depends on the coupling strength in the fluid regime, but exhibits a pronounced decrease with the increase of the screening strength. The limitations of the present approach in applications to real complex plasmas are briefly discussed.
Yukawa and the Birth of Meson Theory: Fiftieth Anniversary for Nuclear Forces.
ERIC Educational Resources Information Center
Spradley, Joseph L.
1985-01-01
In 1935 physicist Hideki Yukawa proposed the meson theory of nuclear forces. Background, influences, and chronology of Yukawa's work are presented and discussed. Yukawa was supported in his meson idea by Japan's strong emphasis on intuitive and creative approaches which are also evident in subsequent developments in that country. (DH)
(mercury.yukawa.kyoto-u.ac.jp)ssh Permission denied (publickey).
Shimizu, Akira
SSH Q&A (mercury.yukawa.kyoto-u.ac.jp)ssh Permission denied (publickey). (1) ID ID ID (2) ssh -i () ssh -i $HOME/.ssh/id_yitp_rsa (UID)@mercury.yukawa.kyoto-u.ac.jp (3) (1)(2) Permission denied support@yukawa.kyoto-u.ac.jp (mercury
Duda, Yurko; Romero-Martínez, Ascención; Orea, Pedro
2007-06-14
The liquid-vapor phase diagram and surface tension for hard-core Yukawa potential with 4
Integral transform of the Coulomb Green's function by the Hankel function and off-shell scattering
NASA Astrophysics Data System (ADS)
Laha, U.; Bhoi, J.
2013-12-01
In the representation space approach a useful analytical expression for the integral transform of the Coulomb Green's function by the Hankel function is constructed via Sturmian representation of the bound-state Coulomb Green's function. This integral transform is exploited to construct off-shell Jost solutions for motion in Coulomb and Coulomb plus separable interactions in the maximal reduced form. The expressions for the corresponding off-shell T matrices are also constructed by using a modified relation between the off-shell physical solution and the T matrix that does not involve the potential explicitly. Finally, off-shell T matrices are computed to examine the role of the Coulomb interaction in proton-proton scattering in the 1S0 channel.
From Lorenz to Coulomb and other explicit gauge transformations
J. D. Jackson
2002-04-17
The main purposes of this paper are (i) to illustrate explicitly by a number of examples the gauge functions chi(x, t) whose spatial and temporal derivatives transform one set of electromagnetic potentials into another equivalent set; and (ii) to show that, whatever propagation or non-propagation characteristics are exhibited by the potentials in a particular gauge, the electric and magnetic fields are always the same and display the experimentally verified properties of causality and propagation at the speed of light. The example of the transformation from the Lorenz gauge (retarded solutions for both scalar and vector potential) to the Coulomb gauge (instantaneous, action-at-a-distance, scalar potential) is treated in detail. A transparent expression is obtained for the vector potential in the Coulomb gauge, with a finite nonlocality in time replacing the expected spatial nonlocality of the transverse current. A class of gauges (v-gauge) is described in which the scalar potential propagates at an arbitrary speed v relative to the speed of light. The Lorenz and Coulomb gauges are special cases of the v-gauge. The last examples of gauges and explicit gauge transformation functions are the Hamiltonian or temporal gauge, the nonrelativistic Poincare or multipolar gauge, and the relativistic Fock-Schwinger gauge.
Four-fermion limit of gauge-Yukawa theories
NASA Astrophysics Data System (ADS)
Krog, Jens; Mojaza, Matin; Sannino, Francesco
2015-10-01
We elucidate and extend the conditions that map gauge-Yukawa theories at low energies into time-honored gauged four-fermion interactions at high energies. These compositeness conditions permit us to investigate theories of composite dynamics through gauge-Yukawa theories. Here we investigate whether perturbative gauge-Yukawa theories can have a strongly coupled limit at high energy that can be mapped into a four-fermion theory. Interestingly, we are able to precisely carve out a region of the perturbative parameter space supporting such a composite limit. This has interesting implications on our current view on models of particle physics. As a template model we use an S U (NC) gauge theory with NF Dirac fermions transforming according to the fundamental representation of the gauge group. The fermions further interact with a gauge singlet complex NF×NF Higgs boson that ceases to be a physical degree of freedom at the ultraviolet composite scale, where it gives away to the four-fermion interactions. We compute the hierarchy between the ultraviolet and infrared composite scales of the theory and show that they are naturally large and well separated. Our results show that some weakly coupled gauge-Yukawa theories can be viewed, in fact, as composite theories. It is therefore tantalizing to speculate that the standard model, with its phenomenological perturbative Higgs sector, could hide, in plain sight, a composite theory.
Scalar Decay Constant and Yukawa Coupling in Walking Gauge Theories
Michio Hashimoto
2011-04-29
We propose an approach for the calculation of the yukawa coupling through the scalar decay constant and the chiral condensate in the context of the extended technicolor (ETC). We perform the nonperturbative computation of the yukawa coupling based on the improved ladder Schwinger-Dyson equation. It turns out that the yukawa coupling can be larger or smaller than the standard model (SM) value, depending on the number $N_D$ of the weak doublets for each technicolor (TC) index. It is thus nontrivial whether or not the huge enhancement of the production of the scalar via the gluon fusion takes place even for a walking TC model with a colored techni-fermion. For the typical one-family TC model near conformality, it is found that the yukawa coupling is slightly larger than the SM one, where the expected mass of the scalar bound state is around 500 GeV. In this case, the production cross section via the gluon fusion is considerably enhanced, as naively expected, and hence such a scalar can be discovered/excluded at the early stage of the LHC.
Scalar decay constant and Yukawa coupling in walking gauge theories
Hashimoto, Michio
2011-05-01
We propose an approach for the calculation of the Yukawa coupling through the scalar decay constant and the chiral condensate in the context of the extended technicolor . We perform the nonperturbative computation of the Yukawa coupling based on the improved ladder Schwinger-Dyson equation. It turns out that the Yukawa coupling can be larger or smaller than the standard model value, depending on the number N{sub D} of the weak doublets for each technicolor (TC) index. It is thus nontrivial whether or not the huge enhancement of the production of the scalar via the gluon fusion takes place even for a walking TC model with a colored techni-fermion. For the typical one-family TC model near conformality, it is found that the Yukawa coupling is slightly larger than the standard model one, where the expected mass of the scalar bound state is around 500 GeV. In this case, the production cross section via the gluon fusion is considerably enhanced, as naively expected, and hence such a scalar can be discovered/excluded at the early stage of the LHC.
On the shear viscosity of 3D Yukawa liquids
Donko, Z.; Hartmann, P.
2008-09-07
We report calculations of the shear viscosity of three-dimensional strongly-coupled Yukawa liquids, based on two different non-equilibrium molecular dynamics methods. The present simulations intend to improve the accuracy of shear viscosity data, compared to those obtained in earlier studies.
The Coulomb Barrier Transmission Coefficient in Nuclear Reactions
NASA Astrophysics Data System (ADS)
Yoon, Jin-Hee
This thesis mainly deals with the Coulomb wavefunctions and their applications in a nuclear fusion theory. When two charged particles come close they interact through a Coulomb potential. As solutions of a Schrodinger equation with the Coulomb potential, we construct the regular and irregular Coulomb wavefunctions. These are used to construct the exterior wavefunctions outside a nucleus that satisfy the boundary conditions at the nuclear surface. We also derive their recurrence relations and asymptotic forms. Some forms of the Coulomb wavefunctions are useful in analytic calculations but are cumbersome in most numerical calculations. A computer code is developed to calculate the values of the Coulomb wavefunctions using power series expansions. The Coulomb wavefunctions are used to calculate the transmission coefficient which plays a crucial role in the calculation of cross sections. Several methods are used to calculate the transmission coefficient in an attempt to fit experimental data both including and excluding a resonance peak. The conventional formula for the transmission coefficient, which is widely used, will be compared with our new formulae which include a realistic nuclear potential inside a nucleus. They provide information both at the nuclear surface and in the inside of the nucleus. Our new methods may be applied to the low energy nuclear fusion reactions involved in the magnetic confinement and inertial fusions and also in astrophysical problems. The results for the nuclear reactions, D(D, p)^3 He, D(D, n)T,^3 He(D, p)^4 He,T(D, n)^4 He, and ^7 Be(p, gamma)^8 B are presented. All the results are consistent with the conventional results within 10%. However, our newly formulated coefficient improve the nuclear reaction data analyses by producing good fits with less physical assumptions without an arbitrary fitting parameter. In this work we confine ourselves to S-waves assuming that the energies interested are low enough to insure our confinement. Finally, it is recommended to include several more angular momentum waves. By including higher angular momentum terms, more plausible fits for the experimental data are expected.
Yukawa Meson, Sakata Model and Baryon-Lepton Symmetry Revisited
NASA Astrophysics Data System (ADS)
Marshak, R. E.
It is difficult for me to grasp that this symposium is celebrating the jubilee of meson theory since I was a junior at Columbia College in 1935. I recall hearing a colloquium by Paul Dirac that year telling an enraptured audience about the infinite sea of negative energy states but I do not recall any special note being taken of the birth of an equally revolutionary concept, the Yukawa meson. Perhaps the reason was the publication of Hideki Yukawa's paper in an inaccessible Japanese journal, perhaps Dirac's electron theory was dealing with the well-known electromagnetic force whereas Yukawa' meson theory was put forth to understand the nature of two new forces - the nuclear and the weak. Whatever the reason, the situation changed drastically when I migrated to Cornell (to do my thesis under Hans Bethe during the years 1937sim39) and found a deep interest in meson theory. Thus, my own scientific career has almost spanned the period since the birth of meson theory but, what is more to the point, it has been strongly influenced by the work of Yukawa and his collaborators. It therefore gives me great pleasure to be able to talk at this MESON 50 symposium. As one of the oldest speakers, I shall respond in a loose way to Professor Maki's invitation to cover ``topics concerning the historical developments of hadron physics''. I shall select several major themes from the Japanese work that have had special interest for me. My remarks will fall under the four headings: (A) Yukawa Meson; (B) Sakata Model; (C) Baryon-Lepton Symmetry; and (D) Extensions of Baryon-Lepton Symmetry.
Solution of two-body relativistic bound state equations with confining plus Coulomb interactions
NASA Technical Reports Server (NTRS)
Maung, Khin Maung; Kahana, David E.; Norbury, John W.
1992-01-01
Studies of meson spectroscopy have often employed a nonrelativistic Coulomb plus Linear Confining potential in position space. However, because the quarks in mesons move at an appreciable fraction of the speed of light, it is necessary to use a relativistic treatment of the bound state problem. Such a treatment is most easily carried out in momentum space. However, the position space Linear and Coulomb potentials lead to singular kernels in momentum space. Using a subtraction procedure we show how to remove these singularities exactly and thereby solve the Schroedinger equation in momentum space for all partial waves. Furthermore, we generalize the Linear and Coulomb potentials to relativistic kernels in four dimensional momentum space. Again we use a subtraction procedure to remove the relativistic singularities exactly for all partial waves. This enables us to solve three dimensional reductions of the Bethe-Salpeter equation. We solve six such equations for Coulomb plus Confining interactions for all partial waves.
Coulomb Branch Localization in Quiver Quantum Mechanics
Ohta, Kazutoshi
2015-01-01
We show how to exactly calculate the refined indices of N=4 U(1) times U(N) supersymmetric quiver quantum mechanics in the Coulomb branch by using the localization technique. The Coulomb branch localization is discussed from the viewpoint of both non-linear and gauged linear sigma models. A classification of fixed points in the Coulomb branch differs from one in the Higgs branch, but the derived indices completely agree with the results which were obtained by the localization in the Higgs branch. In the Coulomb branch localization, the refined indices can be written as a summation over different sets of the Coulomb branch fixed points. We also discuss a space-time picture of the fixed points in the Coulomb branch.
P. Gerhold; K. Jansen
2009-02-24
We study the coupling parameter dependence of the Higgs boson mass in a chirally invariant lattice Higgs-Yukawa model emulating the same Yukawa coupling structure as in the Higgs-fermion sector of the Standard Model. Eventually, the aim is to establish non-perturbative upper and lower Higgs boson mass bounds derived from first principles, in particular not relying on vacuum stability considerations for the latter case. Here, we present our lattice results for the lower Higgs boson mass bound at several values of the cutoff and compare them to corresponding analytical calculations based on the effective potential as obtained from lattice perturbation theory. Furthermore, we give a brief outlook towards the calculation of the upper Higgs boson mass bound.
Phase structure and Higgs boson mass in a Higgs-Yukawa model with a dimension-6 operator
David Y. -J. Chu; Karl Jansen; Bastian Knippschild; C. -J. David Lin; Kei-Ichi Nagai; Attila Nagy
2015-01-01
We investigate the impact of a $\\lambda_6 \\varphi^6$ term included in a chirally invariant lattice Higgs-Yukawa model. Such a term could emerge from BSM physics at some larger energy scale. We map out the phase structure of the Higgs-Yukawa model with positive $\\lambda_6$ and negative quartic self coupling of the scalar fields. To this end, we evaluate the constraint effective potential in lattice perturbation theory and also determine the magnetization of the model via numerical simulations which allow us to reach also non-perturbative values of the couplings. As a result, we find a complex phase structure with first and second order phase transitions identified through the magnetization. Further we analyze the effect of such a $\\varphi^6$ term on the lower Higgs boson mass bound to see, whether the standard model lower mass bound can be altered.
PREFACE: Strongly Coupled Coulomb Systems Strongly Coupled Coulomb Systems
NASA Astrophysics Data System (ADS)
Neilson, David; Senatore, Gaetano
2009-05-01
This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS), held from 29 July-2 August 2008 at the University of Camerino. Camerino is an ancient hill-top town located in the Apennine mountains of Italy, 200 kilometres northeast of Rome, with a university dating back to 1336. The Camerino conference was the 11th in a series which started in 1977: 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (hosted by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (hosted by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, New York, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) 2005: Moscow, Russia (hosted by Vladimir E Fortov and Vladimir Vorob'ev). The name of the series was changed in 1996 from Strongly Coupled Plasmas to Strongly Coupled Coulomb Systems to reflect a wider range of topics. 'Strongly Coupled Coulomb Systems' encompasses diverse many-body systems and physical conditions. The purpose of the conferences is to provide a regular international forum for the presentation and discussion of research achievements and ideas relating to a variety of plasma, liquid and condensed matter systems that are dominated by strong Coulomb interactions between their constituents. Each meeting has seen an evolution of topics and emphases that have followed new discoveries and new techniques. The field has continued to see new experimental tools and access to new strongly coupled conditions, most recently in the areas of warm matter, dusty plasmas, condensed matter and ultra-cold plasmas. One hundred and thirty participants came from twenty countries and four continents to participate in the conference. Those giving presentations were asked to contribute to this special issue to make a representative record of an interesting conference. We thank the International Advisory Board and the Programme Committee for their support and suggestions. We thank the Local Organizing Committee (Stefania De Palo, Vittorio Pellegrini, Andrea Perali and Pierbiagio Pieri) for all their efforts. We highlight for special mention the dedication displayed by Andrea Perali, by Rocco di Marco for computer support, and by our tireless conference secretary Fiorella Paino. The knowledgeable guided tour of the historic centre of Camerino given by Fiorella Paino was appreciated by many participants. It is no exaggeration to say that without the extraordinary efforts put in by these three, the conference could not have been the success that it was. For their sustained interest and support we thank Fulvio Esposito, Rector of the University of Camerino, Fabio Beltram, Director of NEST, Scuola Normale Superiore, Pisa, and Daniel Cox, Co-Director of ICAM, University of California at Davis. We thank the Institute of Complex and Adaptive Matter ICAM-I2CAM, USA for providing a video record of the conference on the web (found at http://sccs2008.df.unicam.it/). Finally we thank the conference sponsors for their very generous support: the University of Camerino, the Institute of Complex and Adaptive Matter ICAM-I2CAM, USA, the International Centre for Theoretical Physics ICTP Trieste, and CNR-INFM DEMOCRITOS Modeling Center for Research in Atomistic Simulation, Trieste. Participants at the International Conference on Strongly Coupled Coulomb Systems (SCCS) (University of Camerino, Italy, 29 July-2 August 2008).
Interatomic Coulombic decay in nanodroplets
NASA Astrophysics Data System (ADS)
Sisourat, Nicolas
2014-05-01
Interatomic (molecular) Coulombic decay (ICD) is an ultrafast non-radiative electronic decay process for excited atoms or molecules embedded in a chemical environment. Via ICD, the excited system can get rid of the excess energy, which is transferred to one of the neighbors and ionize it. ICD produces two charged particles next to each other and thus leads to Coulomb explosion. Kinetic energy distribution of the ionic fragments gives information on the dynamics of the decay process. From the theoretical point of view general quantum mechanical equations for describing the decay processes and the subsequent fragmentations are known but are only applicable for rather small systems. During the presentation, a semiclassical approach for modeling ICD and the subsequent fragmentations will be presented. This approach involves a classical treatment for the nuclear motion while retaining a quantum description for the electron dynamics. Such approach has low computational costs and can be used to study much larger systems. Comparison of the results from semiclassical and from quantum mechanical calculations will be shown for simple systems, demonstrating the good performance of the semiclassical method. Results on ICD in nanodroplets will finally be reported.
Beam-Plasma Interaction and Instabilities in a 2D Yukawa Plasma
NASA Astrophysics Data System (ADS)
Kyrkos, S.; Kalman, G.; Rosenberg, M.
2008-11-01
In a complex plasma, penetrating charged particle beams may lead to beam-plasma instabilities. When either the plasma, the beam, or both, are strongly interacting [1], the features of the instability are different from those in a weakly coupled plasma. We consider the case when a 2D dusty plasma forms a lattice, and the beam is moving in the lattice plane. Both the grains and the beam particles interact through a Yukawa potential; the beam particles are weakly coupled to each other and to the lattice. The system develops both a longitudinal and a transverse instability. Based on the phonon spectrum of a 2D hexagonal Yukawa lattice [2], we determine and compare the transverse and longitudinal growth rates. As a function of the wavenumber, the growth rates exhibit remarkable gaps, where no instability is excited. The gap locations are governed by the ratio of the lattice and the beam plasma frequencies. The behavior of the growth rates also depends on the direction of the beam and on the relationship between the beam speed and the longitudinal and transverse sound speeds. [1] GJ Kalman, M Rosenberg, JPA 36, 5963 (2003). [2] T Sullivan, GJ Kalman, S Kyrkos, P Bakshi, M Rosenberg, Z Donko, JPA 39, 4607 (2006).
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??,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.
Comparison of COULOMB-2, NASCAP-2k and SPIS codes for geostationary spacecrafts charging
NASA Astrophysics Data System (ADS)
Novikov, Lev; Makletsov, Andrei; Sinolits, Vadim
In developing of international standards for spacecraft charging, it is necessary to compare results of spacecraft charging modeling obtained with various models. In the paper, electrical potentials for spacecraft 3D models were calculated with COULOMB-2, NASCAP-2k [1] and SPIS [2] software, and the comparison of obtained values was performed. To compare COULOMB-2 and NASCAP-2k codes we used a 3D geometrical model of a spacecraft given in [1]. Parameters of spacecraft surface materials were taken from [1], too. For COULOMB-2 and SPIS cross validation, we carried out calculations with SPIS code through SPENVIS web-interface and with COULOMB-2 software for a spacecraft geometrical model given in SPIS test examples [2]. In both cases, we calculated distributions of electric potentials on the spacecraft surface and visualized the obtained distributions with color code. Pictures of the surface potentials distribution calculated with COULOMB-2 and SPIS software are in good qualitative agreement. Absolute values of surface potentials calculated with these codes for different plasma conditions, are close enough. Pictures of the surface potentials distribution calculated for the spacecraft model [1] with COULOMB-2 software completely correspond to actual understanding of physical mechanisms of differential spacecraft surface charging. In this case, we compared only calculated values of the surface potential for the same space plasma conditions because the potential distributions on the spacecraft surface are absent in [1]. For all the plasma conditions considered, COULOMB-2 model gives higher absolute values of negative potential, than NASCAP-2k model. Differences in these values reach 2-3 kV. The possible explanations of the divergences indicated above are distinctions in calculation procedures of primary plasma currents and secondary emission currents. References 1. Ferguson D.?., Wimberly S.C. 51st AIAA Aerospace Science Meeting 2013 (AIAA 2013-0810). 2. http://dev.spis.org/projects/spine/home/spis
Why should we care about the top quark Yukawa coupling?
Shapshnikov, Mikhail; Bezrukov, Fedor
2015-04-15
In the cosmological context, for the Standard Model to be valid up to the scale of inflation, the top quark Yukawa coupling yt should not exceed the critical value ytcrit , coinciding with good precision (about 0.2‰) with the requirement of the stability of the electroweak vacuum. So, the exact measurements of yt may give an insight on the possible existence and the energy scale of new physics above 100 GeV, which is extremely sensitive to yt. In this study, we overview the most recent theoretical computations of and the experimental measurements of ytcrit and the experimental measurements ofmore »yt. Within the theoretical and experimental uncertainties in yt, the required scale of new physics varies from 10? GeV to the Planck scale, urging for precise determination of the top quark Yukawa coupling.« less
Study of Coulomb interactions at VECC energies
Varinderjit Kaur; Suneel Kumar; Rajeev K. Puri; S. Bhattacharya
2011-07-29
we study the effect of Coulomb interactions on balance energy for various colliding nuclei in terms of mass asymmetry. This study shows that the balance energy is affected by the Coulomb interactions as well as different nuclear equations of state. The preliminary results calculated theoretically will be of great use for scientists at VECC. This study is further in progress.
The One-Dimensional Soft-Coulomb Problem and the Hard-Coulomb Limit
NASA Astrophysics Data System (ADS)
Weatherford, Charles; Gebremedhin, Daniel
2014-05-01
A new and efficient way of evolving a solution to an ordinary differential equation is presented. A finite element method is used where we expand in a convenient local basis set of functions that enforce both function and first derivative continuity across the boundary. We also, for the first time, implement an adaptive step size choice for each element that is based on a Taylor series expansion. This algorithm is used to solve for the eigenpairs corresponding to the one-dimensional soft Coulomb potential, 1 /?{x2 +?2 } , which becomes numerically intractable as the softening parameter (?) approaches zero. We are able to maintain near machine accuracy for ? as low as ? =10-8 using 16 digit precision calculations. Our numerical results provide a new insight into the controversial one dimensional Hydrogen atom which is a limiting case of the soft Coulomb problem as ? --> 0 . CAW was supported by the Defense Threat Reduction Agency, and CAW and DG were both supported by the National Nuclear Security Agency.
Hard-core yukawa model for charge-stabilized colloids
Davoudi; Kohandel; Mohammadi; Tanatar
2000-11-01
The hypernetted chain approximation is used to study the phase diagram of a simple hardcore Yukawa model of a charge-stabilized colloids. We calculate the static structure factor, the pair distribution function, and the collective mode energies over a wide range of parameters, and the results are used for studying the freezing transition of the system. The resulting phase diagram is in good agreement with the known estimates and the Monte Carlo simulations. PMID:11102053
Hideki Yukawa ---January 23, 1907 - September 8, 1981---
NASA Astrophysics Data System (ADS)
Tanikawa, Y.
1981-10-01
Hideki Yukawa took the first step in his research in 1929 as an associate at Kyoto Imperial University (nowadays called Kyoto University). Most Japanese physicists of those days were isolated far from Western centers of physical science, where the `Sturm und Drang' of astonighing developments in the twentieth century physics had been roaring. There were only a handful of physicists in Japan who had already set to work in quantum physics, but never any one working on the quantum field theory and theoretical nuclear physics. Yukawa had to initiate his study of these frontiers of physical science by himself, without any teacher or senior scholar in this field. In 1935, Yukawa published his first paper with the title ``On the Interaction of Elementary Particles. I'', in which he developed the revolutionary idea of the meson theory. Although even the term `elementary particle' was not so popular in those days, the meson theory was proposed as a unified theory of interactions of elementary particles. His theory opened up a new fundamental view of Nature. This event might be regarded as a miracle in the history of Japanese physics. Through all of his works and thoughts, we are impressed by the simplicity of approach, the unfailing intuition and the creativity of a great master, which are deep-rooted in his culture. A sketch of his life, mainly based on his autobiographical material and partly based on the present writer's personal recollection, is presented to show his thought and activity.
NLSP gluino and NLSP stop scenarios from b -? Yukawa unification
NASA Astrophysics Data System (ADS)
Raza, Shabbar; Shafi, Qaisar; Ün, Cem Salih
2015-09-01
We present a study of the b -? Yukawa unified supersymmetric S U (4 )c×S U (2 )L×S U (2 )R model (with ? >0 ), which predicts the existence of gluino—neutralino and stop—neutralino coannihilation scenarios compatible with the desired relic lightest supersymmetric particle neutralino dark matter abundance and other collider constraints. The next to lightest supersymmetric particle (NLSP) gluino or NLSP stop masses vary between 400 GeV and ˜1 TeV . The NLSP gluinos will be accessible at the 14 TeV LHC, while we hope that the NSLP stop solutions will be probed in future LHC searches. We also identify regions of the parameter space in which the gluino and the lighter stop are closely degenerate in mass, interchangeably playing the role of NLSP and next to next to lightest supersymmetric particle (NNLSP). We also update a previous study of t -b -? Yukawa unification and show that NLSP gluino of mass ˜1 TeV , with a mass difference between the gluino and neutralino of less than 80 GeV, can be realized, consistent with the current collider and astrophysical constraints. We present benchmark points for b -? and t -b -? Yukawa unification that can be accessible at the LHC.
Gravity Dual Corrections to the Heavy Quark Potential at Finite-Temperature
Hovhannes R. Grigoryan; Yuri V. Kovchegov
2011-06-23
We apply gauge/gravity duality to compute $1/N^2_c$ corrections to the heavy quark potentials of a quark--anti-quark pair ($Q\\bar Q$) and of a quark--quark pair ($QQ$) immersed into the strongly coupled N = 4 SYM plasma. On the gravity side these corrections come from the exchanges of supergravity modes between two string worldsheets stretching from the UV boundary of AdS space to the black hole horizon in the bulk and smeared over $S^5$. We find that the contributions to the $Q\\bar Q$ potential coming from the exchanges of all of the relevant modes (such as dilaton, massive scalar, 2-form field, and graviton) are all attractive, leading to an attractive net $Q\\bar Q$ potential. We show that at large separations $r$ and/or high-temperature $T$ the potential is of Yukawa-type, dominated by the graviton exchange, in agreement with earlier findings. On the other hand, at small-$r T$ the $Q\\bar Q$ potential scales as $\\sim (1/r) \\ln (1/rT)$. In the case of $QQ$ potential the 2-form contribution changes sign and becomes repulsive: however, the net $QQ$ potential remains attractive. At large-$r T$ it is dominated by the graviton exchange, while at small-$r T$ the $QQ$ potential becomes Coulomb-like.
Extended Kepler-Coulomb quantum superintegrable systems in 3 dimensions
E. G. Kalnins; J. M. Kress; W. Miller Jr
2012-11-13
The quantum Kepler-Coulomb system in 3 dimensions is well known to be 2nd order superintegrable, with a symmetry algebra that closes polynomially under commutators. This polynomial closure is also typical for 2nd order superintegrable systems in 2D and for 2nd order systems in 3D with nondegenerate (4-parameter) potentials. However the degenerate 3-parameter potential for the 3D Kepler-Coulomb system (also 2nd order superintegrable) is an exception, as its symmetry algebra doesn't close polynomially. The 3D 4-parameter potential for the extended Kepler-Coulomb system is not even 2nd order superintegrable, but Verrier and Evans (2008) showed it was 4th order superintegrable, and Tanoudis and Daskaloyannis (2011) showed that, if a 2nd 4th order symmetry is added to the generators, the symmetry algebra closes polynomially. Here, based on the Tremblay, Turbiner and Winternitz construction, we consider an infinite class of quantum extended Kepler-Coulomb 3 and 4-parameter systems indexed by a pair of rational numbers (k_1,k_2) and reducing to the usual systems when k_1=k_2=1. We show these systems to be superintegrable of arbitrarily high order and determine the structure of their symmetry algebras. We demonstrate that the symmetry algebras close algebraically; only for systems admitting extra discrete symmetries is polynomial closure achieved. Underlying the structure theory is the existence of raising and lowering operators, not themselves symmetry operators or even defined independent of basis, that can be employed to construct the symmetry operators and their structure relations.
Coulomb Blockade with Neutral Modes
NASA Astrophysics Data System (ADS)
Kamenev, Alex; Gefen, Yuval
2015-04-01
We study transport through a quantum dot in the fractional quantum Hall regime with filling factors ? =2 /3 and ? =5 /2 , weakly coupled to the leads. We account for both injection of electrons to or from the leads, and quasiparticle rearrangement processes between the edge and the bulk of the quantum dot. The presence of neutral modes introduces topological constraints that modify qualitatively the features of the Coulomb blockade (CB). The periodicity of CB peak spacings doubles and the ratio of spacing between adjacent peaks approaches (in the low temperature and large dot limit) a universal value: 2 ?1 for ? =2 /3 and 3 ?1 for ? =5 /2 . The corresponding CB diamonds alternate their width in the direction of the bias voltage and allow for the determination of the neutral mode velocity, and of the topological numbers associated with it.
PREFACE: Strongly Coupled Coulomb Systems
NASA Astrophysics Data System (ADS)
Fortov, Vladimir E.; Golden, Kenneth I.; Norman, Genri E.
2006-04-01
This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS) which was held during the week of 20 24 June 2005 in Moscow, Russia. The Moscow conference was the tenth in a series of conferences. The previous conferences were organized as follows. 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (organized by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (organized by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, NY, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) After 1995 the name of the series was changed from `Strongly Coupled Plasmas' to the present name in order to extend the topics of the conferences. The planned frequency for the future is once every three years. The purpose of these conferences is to provide an international forum for the presentation and discussion of research accomplishments and ideas relating to a variety of plasma liquid and condensed matter systems, dominated by strong Coulomb interactions between their constituents. Strongly coupled Coulomb systems encompass diverse many-body systems and physical conditions. Each meeting has seen an evolution of topics and emphasis as new discoveries and new methods appear. This year, sessions were organized for invited presentations and posters on dense plasmas and warm matter, astrophysics and dense hydrogen, non-neutral and ultracold plasmas, dusty plasmas, condensed matter 2D and layered charged-particle systems, Coulomb liquids, and statistical theory of SCCS. Within each area new results from theory, simulations and experiments were presented. In addition, a special symposium was held one evening to explore the questions on high-energy-density matter generated by intense heavy ion beams and to discuss the outlook for applications to industry. As this special issue illustrates, the field remains vibrant and challenging, being driven to a great extent by new experimental tools and access to new strongly coupled conditions. This is illustrated by the inclusion of developments in the areas of warm matter, dusty plasmas, condensed matter and ultra-cold plasmas. In total, 200 participants from 17 countries attended the conference, including 42 invited speakers. The individuals giving presentations at the conference, including invited plenary and topical talks and posters, were asked to contribute to this special issue and most have done so. We trust that this special issue will accurately record the contents of the conference, and provide a valuable resource for researchers in this rapidly evolving field. We would like to thank the members of the International Advisory Board and all members of the Programme Committee for their contributions to the conference. Of course, nothing would have been possible without the dedicated efforts of the Local Organizing Committee, in particular Igor Morozov and Valery Sultanov. We wish to thank the Russian Academy of Sciences, the Institute for High Energy Densities, the Institute of Problems of Chemical Physics, the Moscow Institute of Physics and Technology, the Ministry of Education and Science of the Russian Federation, the Russian Foundation for Basic Research, the Moscow Committee of Science and Technologies, the Russian Joint Stock Company `Unified Energy System of Russia', and The International Association for the Promotion of Co-operation with Scientists from the New Independent States (NIS) of the Former Soviet Union for sponsoring this conference.
NASA Astrophysics Data System (ADS)
Land-Frs Collaboration; Nociforo, C.; Jones, K. L.; Khiem, L. H.; Adrich, P.; Aumann, T.; Carlson, B. V.; Cortina-Gil, D.; Datta Pramanik, U.; Elze, Th. W.; Emling, H.; Geissel, H.; Hellström, M.; Kratz, J. V.; Kulessa, R.; Lange, T.; Leifels, Y.; Lenske, H.; Lubkiewicz, E.; Münzenberg, G.; Palit, R.; Scheit, H.; Simon, H.; Sümmerer, K.; Typel, S.; Wajda, E.; Walus, W.; Weick, H.
2005-01-01
The ground-state structure of the near-drip-line nucleus 23O has been investigated in a one-neutron Coulomb breakup reaction. Differential cross sections d?/dE* for electromagnetic excitation of 23O projectiles (422 MeV/nucleon) incident on a lead target have been obtained from the measurement of the momenta of all breakup products including ? rays. The analysis of the deduced dipole-transition probability into the continuum infers a 2s1/2?O22(0+) ground state configuration with a spectroscopic factor of 0.77(10) and thus a ground-state spin I?(O23)=1/2+, resolving earlier conflicting experimental findings. Final-state interaction is of significant influence, an effective reduced scattering length for low-energy p3/2 neutron scattering could be derived from the data.
NASA Astrophysics Data System (ADS)
Nociforo, C.; Jones, K. L.; Khiem, L. H.; Adrich, P.; Aumann, T.; Carlson, B. V.; Cortina-Gil, D.; Datta Pramanik, U.; Elze, Th. W.; Emling, H.; Geissel, H.; Hellström, M.; Kratz, J. V.; Kulessa, R.; Lange, T.; Leifels, Y.; Lenske, H.; Lubkiewicz, E.; Münzenberg, G.; Palit, R.; Scheit, H.; Simon, H.; Sümmerer, K.; Typel, S.; Wajda, E.; Walus, W.; Weick, H.; LAND-FRS Collaboration
2005-01-01
The ground-state structure of the near-drip-line nucleus 23O has been investigated in a one-neutron Coulomb breakup reaction. Differential cross sections d? / dE* for electromagnetic excitation of 23O projectiles (422 MeV/nucleon) incident on a lead target have been obtained from the measurement of the momenta of all breakup products including ? rays. The analysis of the deduced dipole-transition probability into the continuum infers a 2s1 / 2 ?22O (0+) ground state configuration with a spectroscopic factor of 0.77(10) and thus a ground-state spin I? (23O) = 1 /2+, resolving earlier conflicting experimental findings. Final-state interaction is of significant influence, an effective reduced scattering length for low-energy p3 / 2 neutron scattering could be derived from the data.
Temperature dependence of Coulomb oscillations in a few-layer two-dimensional WS2 quantum dot.
Song, Xiang-Xiang; Zhang, Zhuo-Zhi; You, Jie; Liu, Di; Li, Hai-Ou; Cao, Gang; Xiao, Ming; Guo, Guo-Ping
2015-01-01
Standard semiconductor fabrication techniques are used to fabricate a quantum dot (QD) made of WS2, where Coulomb oscillations were found. The full-width-at-half-maximum of the Coulomb peaks increases linearly with temperature while the height of the peaks remains almost independent of temperature, which is consistent with standard semiconductor QD theory. Unlike graphene etched QDs, where Coulomb peaks belonging to the same QD can have different temperature dependences, these results indicate the absence of the disordered confining potential. This difference in the potential-forming mechanism between graphene etched QDs and WS2 QDs may be the reason for the larger potential fluctuation found in graphene QDs. PMID:26538164
Temperature dependence of Coulomb oscillations in a few-layer two-dimensional WS2 quantum dot
NASA Astrophysics Data System (ADS)
Song, Xiang-Xiang; Zhang, Zhuo-Zhi; You, Jie; Liu, Di; Li, Hai-Ou; Cao, Gang; Xiao, Ming; Guo, Guo-Ping
2015-11-01
Standard semiconductor fabrication techniques are used to fabricate a quantum dot (QD) made of WS2, where Coulomb oscillations were found. The full-width-at-half-maximum of the Coulomb peaks increases linearly with temperature while the height of the peaks remains almost independent of temperature, which is consistent with standard semiconductor QD theory. Unlike graphene etched QDs, where Coulomb peaks belonging to the same QD can have different temperature dependences, these results indicate the absence of the disordered confining potential. This difference in the potential-forming mechanism between graphene etched QDs and WS2 QDs may be the reason for the larger potential fluctuation found in graphene QDs.
Temperature dependence of Coulomb oscillations in a few-layer two-dimensional WS2 quantum dot
Song, Xiang-Xiang; Zhang, Zhuo-Zhi; You, Jie; Liu, Di; Li, Hai-Ou; Cao, Gang; Xiao, Ming; Guo, Guo-Ping
2015-01-01
Standard semiconductor fabrication techniques are used to fabricate a quantum dot (QD) made of WS2, where Coulomb oscillations were found. The full-width-at-half-maximum of the Coulomb peaks increases linearly with temperature while the height of the peaks remains almost independent of temperature, which is consistent with standard semiconductor QD theory. Unlike graphene etched QDs, where Coulomb peaks belonging to the same QD can have different temperature dependences, these results indicate the absence of the disordered confining potential. This difference in the potential-forming mechanism between graphene etched QDs and WS2 QDs may be the reason for the larger potential fluctuation found in graphene QDs. PMID:26538164
Aspect of Fermion Mass Hierarchy within Flavor Democracy for Yukawa Couplings
NASA Astrophysics Data System (ADS)
Higuchi, Katsuichi; Yamamoto, Katsuji
We discuss the fermion mass hierarchy by including vector-like fermions which are accommodated in E6 GUTs within flavor democracy for Yukawa couplings. In this framework, all Yukawa couplings for the standard Higgs doublet have the same strength, and all Yukawa couplings for the singlet Higgs have the same strength (New ansatz). In addition, singlet Higgs and right-handed neutrinos exist. Under this condition, the mass hierarchy mt ? mb ˜ m? as well as mt ? mc, mu can be naturally explained.
Coulomb crystallization of sympathetically cooled highly charged ions
NASA Astrophysics Data System (ADS)
Crespo López-Urrutia, José R.
2015-05-01
Wave functions of inner-shell electrons significantly overlap with the nucleus, whereby enormously magnified relativistic, quantum electrodynamic (QED) and nuclear size effects emerge. In highly charged ions (HCI), the relative reduction of electronic correlations contributions improves the visibility of these effects. This well known facts have driven research efforts with HCI, yet the typically high temperatures at which these can be prepared in the laboratory constitutes a serious hindrance for application of laser spectroscopic methods. The solution for this, cooling HCI down to crystallization has remained an elusive target for more than two decades. By applying laser cooling to an ensemble of Be+ ions, we build Coulomb crystals that we use for stopping the motion of HCI and for cooling them. HCI, in this case Ar13+ ions are extracted from an electron beam ion trap with an energy spread of a few 100's of eV, due to the ion temperature within the trap. Carefully timed electric pulses in a potential-gradient decelerate and bunch the HCI. We achieve Coulomb crystallization of these HCI by re-trapping them in a cryogenic linear radiofrequency trap where they are sympathetically cooled through Coulomb interaction with the directly laser-cooled ensemble. Furthermore, we also demonstrate cooling of a single Ar13+ ion by a single Be+ ion, prerequisite for quantum logic spectroscopy with potentially 10-19 relative accuracy. The strongly suppressed thermal motion of the embedded HCI offers novel possibilities for investigation of questions related to the time variation of fundamental constants, parity non-conservation effects, Lorentz invariance and quantum electrodynamics. Achieving a seven orders-of-magnitude decrease in HCI temperature, from the starting point at MK values in the ion source down to the mK range within the Coulomb crystal eliminates the major obstacle for HCI investigation with high precision laser spectroscopy and quantum computation schemes.
Measurement of the leptoquark Yukawa couplings in e+e- collisions at TESLA
Aleksander Filip Zarnecki
2001-02-22
Measurement of the Yukawa couplings of the first-generation leptoquarks has been studied for e+e- collisions at TESLA, at sqrt(s)=800 GeV. By combining measurements from different production and decay channels, determination of Yukawa couplings with precision on the few per-cent level is possible. TESLA will be sensitive to very small leptoquark Yukawa couplings not accessible at LHC, down to lambda ~ 0.05 [e]. Distinction between left-handed and right-handed Yukawa couplings is feasible even for leptoquark masses very close to the pair-production kinematic limit.
Yukawa terms in noncommutative SO(10) and E{sub 6} GUTs
Martin, C. P.
2010-10-15
We propose a method for constructing Yukawa terms for noncommutative SO(10) and E{sub 6} GUTs when these GUTs are formulated within the enveloping-algebra formalism. The most general noncommutative Yukawa term that we propose contains, at first order in {theta}{sup {mu}{nu},} the most general Becchi-Rouet-Stora invariant Yukawa contribution whose only dimensionful parameter is the noncommutativity parameter. This noncommutative Yukawa interaction is thus renormalizable at first order in {theta}{sup {mu}{nu}}.
Viscosity of confined two-dimensional Yukawa liquids: A nonequilibrium method
NASA Astrophysics Data System (ADS)
Landmann, S.; Kählert, H.; Thomsen, H.; Bonitz, M.
2015-09-01
We present a nonequilibrium method that allows one to determine the viscosity of two-dimensional dust clusters in an isotropic confinement. By applying a tangential external force to the outer parts of the cluster (e.g., with lasers), a sheared velocity profile is created. The decay of the angular velocity towards the center of the confinement potential is determined by a balance between internal (viscosity) and external friction (neutral gas damping). The viscosity can then be calculated from a fit of the measured velocity profile to a solution of the Navier-Stokes equation. Langevin dynamics simulations are used to demonstrate the feasibility of the method. We find good agreement of the measured viscosity with previous results for macroscopic Yukawa plasmas.
Light-Front Quantization with Explicit Lorentz Symmetry for Yukawa Model
NASA Astrophysics Data System (ADS)
Przeszowski, Jerzy A.; ?ochowski, Jan
2015-09-01
The Dirac method for constrained systems is incomplete for the light-front (LF) quantization of the Yukawa model in D = 1 + 1 dimensions. A novel quantization procedure is proposed, where one obtains the LF commutator and anti-commutators directly from the Heisenberg equations generated by P +, which is a kinematical operator. By adding the general assumptions on the quantum field theory, one evalutes 2-point Wightman functions for a free field case. The Lorentz symmetry is manifest at every step of this novel LF procedure. The Gaussian effective potential is defined with the point-splitting regularization with a space-like separation. The optimum values of the mass parameters are regularization independent.
Coulomb dissociation, a tool for nuclear astrophysics
G. Baur; S. Typel
2007-08-07
A short status report on Coulomb dissociation, an indirect method for nuclear astrophysics is given. An analytically solvable approach to study electromagnetic excitation in ^{11}Be, the archetype of a halo nucleus, is proposed.
Crystallization in two-component Coulomb systems.
Bonitz, M; Filinov, V S; Fortov, V E; Levashov, P R; Fehske, H
2005-12-01
The analysis of Coulomb crystallization is extended from one-component to two-component plasmas. Critical parameters for the existence of Coulomb crystals are derived for both classical and quantum crystals. In the latter case, a critical mass ratio of the two charged components is found, which is of the order of 80. Thus, holes in semiconductors with sufficiently flat valence bands are predicted to spontaneously order into a regular lattice. Such hole crystals are intimately related to ion Coulomb crystals in white dwarf and neutron stars as well as to ion crystals produced in the laboratory. A unified phase diagram of two-component Coulomb crystals is presented and is verified by first-principles computer simulations. PMID:16384315
Coulomb screening in linear coasting nucleosynthesis
Singh, Parminder
2015-01-01
We investigate the impact of coulomb screening on primordial nucleosynthesis in a universe having scale factor that evolves linearly with time. Coulomb screening affects primordial nucleosynthesis via enhancement of thermonuclear reaction rates. This enhancement is determined by the solving Poisson equation within the context of mean field theory (under appropriate conditions during the primordial nucleosynthesis). Using these results, we claim that the mean field estimates of coulomb screening hardly affect the predicted element abundances and nucleosynthesis parameters$, \\{\\eta_9,\\xi_e\\}$. The deviations from mean field estimates are also studied in detail by boosting genuine screening results with the screening parameter ($\\omega_s$). These deviations show negligible effect on the element abundances and on nucleosynthesis parameters. This work thus rules out the coulomb screening effects on primordial nucleosynthesis in slow evolving models and confirms that constraints in ref.[7] on nucleosynthesis parame...
Diffusion coefficient of three-dimensional Yukawa liquids
Dzhumagulova, K. N.; Ramazanov, T. S.; Masheeva, R. U.
2013-11-15
The purpose of this work is an investigation of the diffusion coefficient of the dust component in complex plasma. The computer simulation of the Yukawa liquids was made on the basis of the Langevin equation, which takes into account the influence of buffer plasma on the dust particles dynamics. The Green–Kubo relation was used to calculate the diffusion coefficient. Calculations of the diffusion coefficient for a wide range of the system parameters were performed. Using obtained numerical data, we constructed the interpolation formula for the diffusion coefficient. We also show that the interpolation formula correctly describes experimental data obtained under microgravity conditions.
Memorial Archival Libraries of Yukawa, Tomonaga, and Sakata
NASA Astrophysics Data System (ADS)
Takaiwa, Yoshinobu; Bando, Masako; Gotoh, Haruyoshi; Hayakawa, Hisao; Hirata, Kohji; Ito, Kazuyuki; Ito, Kenji; Kanaya, Kazuyuki; Konagaya, Daisuke; Konuma, Michiji; Kugo, Taichiro; Namba, Chusei; Nishitani, Tadashi; Tanabashi, Masaharu; Tanaka, Kio; Tanaka, Sho; Ukegawa, Fumihiko; Yoshikawa, Tadashi
Brief history of the memorial archival libraries of Hideki Yukawa, Sin-itiro Tomonaga, and Shoichi Sakata, the great pioneers of nuclear and particle physics in Japan, is described. A recent project of maintaining the archival libraries is going on and the catalog databases of their documents are now almost ready for public access using Internet. In the project it is tried to make use of recent knowledge and technologies of archival science and the databases, and thus the documents themselves, willbe made accessible easier than before and may attract the interest of much broader range of audiences. Some interesting documents are picked up for demonstration.
Yukawa couplings and seesaw neutrino masses in noncommutative gauge theory
Raul Horvat; Amon Ilakovac; Peter Schupp; Josip Trampetic; Jiangyang You
2012-07-21
We consider Yukawa couplings in a theta-exact approach to noncommutative gauge field theory and show that both Dirac and singlet Majorana neutrino mass terms can be consistently accommodated. This shows that in fact the whole neutrino-mass extended standard model on noncommutative spacetime can the formulated in the new nonperturbative (in theta) approach which eliminates the previous restriction of Seiberg-Witten map based theories to low-energy phenomena. Spacetime noncommutativity induced couplings between neutrinos and photons as well as Z-bosons appear quite naturally in the model. We derive relevant Feynman rules for the type I seesaw mechanism.
Beam-Plasma Instabilities in a 2D Yukawa Lattice
Kyrkos, S.; Kalman, G. J.; Rosenberg, M.
2009-06-05
We consider a 2D Yukawa lattice of grains, with a beam of other charged grains moving in the lattice plane. In contrast to Vlasov plasmas, where the electrostatic instability excited by the beam is only longitudinal, here both longitudinal and transverse instabilities of the lattice phonons can develop. We determine and compare the transverse and longitudinal growth rates. The growth rate spectrum in wave number space exhibits remarkable gaps where no instability can develop. Depending on the system parameters, the transverse instability can be selectively excited.
Recent developments in Coulomb breakup calculations
Capel, P.
2008-05-12
The theory of reactions applied to Coulomb breakup of loosely-bound projectiles is reviewed. Both the Continuum Discretized Coupled Channel (CDCC) and time-dependent models are described. Recent results about sensitivity of breakup calculations to the projectile wave function are reviewed. Analyses of the extraction of radiative-capture cross section from Coulomb breakup measurements are presented. Current developments in breakup theory are also mentioned.
SLE($?,?$)and Boundary Coulomb Gas
S. Moghimi-Araghi; M. A. Rajabpour; S. Rouhani
2005-08-07
We consider the coulomb gas model on the upper half plane with different boundary conditions, namely Drichlet, Neuman and mixed. We related this model to SLE($\\kappa,\\rho$) theories. We derive a set of conditions connecting the total charge of the coulomb gas, the boundary charges, the parameters $\\kappa$ and $\\rho$. Also we study a free fermion theory in presence of a boundary and show with the same methods that it would lead to logarithmic boundary changing operators.
Scattering states of Dirac equation in the presence of cosmic string for Coulomb interaction
NASA Astrophysics Data System (ADS)
Hosseinpour, M.; Hassanabadi, H.
2015-07-01
We study the covariant Dirac equation in the space-time generated by a cosmic string in presence of vector and scalar potentials of electromagnetic field. We obtain the solution of the radial part of Dirac equation. We consider the scattering states under the Coulomb potential and obtain the phase shifts.
SO(10) grand unified theories with dynamical Yukawa couplings
NASA Astrophysics Data System (ADS)
Aulakh, Charanjit S.; Khosa, Charanjit K.
2014-08-01
Renormalizable SO(10) grand unified theories (GUTs), extended by O(Ng)F family gauge symmetry, generate minimal supersymmetric Standard Model flavor structure dynamically via vacuum expectation values of "Yukawon" Higgs multiplets. For concrete illustration and calculability, we work with the fully realistic minimal supersymmetric GUTs based on the 210?126 ¯?126 GUT Higgs system—which were already parameter counting minimal relative to other realistic models. SO(10) fermion Higgs channels 126 ¯,10(120) extend to symmetric (antisymmetric) representations of O(Ng)F, while 210,126 are symmetric. Ng=3 dynamical Yukawa generation reduces the matter fermion Yukawas from 15 to 3 (21 to 5) without (with) the 120 Higgs. Yukawon GUTs are thus ultraminimal in parameter counting terms. Consistent symmetry breaking is ensured by a hidden sector Bajc-Melfo superpotential with a pair of symmetric O(Ng) multiplets ?,S, of which the latter's singlet part Ss breaks supersymmetry and the traceless part S ^ furnishes flat directions to cancel the O(Ng) D-term contributions of the visible sector. Novel dark matter candidates linked to flavor symmetry arise from both the Bajc-Melfo sector and GUT sector minimal supersymmetric Standard Model singlet pseudo-Goldstones. These relics may be viable light (<50 GeV) cold dark matter as reported by DAMA/LIBRA. In contrast to the new minimal supersymmetric SO(10) grand unified theory (NMSGUT) even sterile neutrinos can appear in certain branches of the flavor symmetry breaking without the tuning of couplings.
Is Hideki Yukawa's explanation of the strong force correct?
NASA Astrophysics Data System (ADS)
Vasiliev, Victor; Moon, Russell
2006-11-01
Reexamining Hideki Yukawa's explanation of the strong force using the principles of the Quark Theory and the Vortex Theory, it was discovered that it is possible for a virtual particle to be passed back and forth between the proton and the neutron. This discovery creates a new and revolutionary explanation of the strong force of nature. The creation of the strong force appears to be the combination of four processes at work in the nucleus: virtual particles, intrinsic magnetism, ``nuclear gravity'', and gluons. 1. V.V. Vasiliev, R.G. Moon, The bases of the vortex theory, Book of abstracts The 53 International Meeting on Nuclear Spectroscopy and Nuclear structure St. Petersburg, Russia, 2003, p.251. 2. H. Yukawa, Tabibito, (World Scientific, Singapore, 1982), p. 190-202. 3. K. Gridnev, V.V. Vasiliev, R.G. Moon, The Photon Acceleration Effect, Book of abstracts, OMEGA 5 -- Symposium on Origin of Matter and Evolution of Galaxies, Nov 8-11, University of Tokyo, Tokyo Japan. 4. R.G. Moon, V.V. Vasiliev. Explanation of the Conservation of Lepton Number, Book of abstracts LV. National Conference on Nuclear Physics, Frontiers in the Physics of Nucleus, June 28-July 1, 2005, Saint-Petersburg, Russia, 2005, p. 347.5. .
Is Hideki Yukawa's explanation of the strong force correct?
NASA Astrophysics Data System (ADS)
Vasiliev, Victor; Moon, Russell
2006-10-01
Reexamining Hideki Yukawa's explanation of the strong force using the principles of the Quark Theory and the Vortex Theory, it was discovered that it is possible for a virtual particle to be passed back and forth between the proton and the neutron. This discovery creates a new and revolutionary explanation of the strong force of nature. The creation of the strong force appears to be the combination of four processes at work in the nucleus: virtual particles, intrinsic magnetism, ``nuclear gravity'', and gluons. 1. V.V. Vasiliev, R.G. Moon, The bases of the vortex theory, Book of abstracts The 53 International Meeting on Nuclear Spectroscopy and Nuclear structure St. Petersburg, Russia, 2003, p.251. 2. H. Yukawa, Tabibito, (World Scientific, Singapore, 1982), p. 190-202. 3. K. Gridnev, V.V. Vasiliev, R.G. Moon, The Photon Acceleration Effect, Book of abstracts, OMEGA 5 -- Symposium on Origin of Matter and Evolution of Galaxies, Nov 8-11, University of Tokyo, Tokyo Japan. 4. R.G. Moon, V.V. Vasiliev. Explanation of the Conservation of Lepton Number, Book of abstracts LV. National Conference on Nuclear Physics, Frontiers in the Physics of Nucleus, June 28-July 1, 2005, Saint-Petersburg, Russia, 2005, p. 347.5. .
LHC phenomenology of SO(10) models with Yukawa unification. II.
NASA Astrophysics Data System (ADS)
Anandakrishnan, Archana; Bryant, B. Charles; Raby, Stuart
2014-07-01
In this paper we study Yukawa-unified SO(10) supersymmetric (SUSY) grand unified theories (GUTs) with two types of SO(10) boundary conditions: (i) universal gaugino masses and (ii) nonuniversal gaugino masses with effective "mirage" mediation. With these boundary conditions, we perform a global ?2 analysis to obtain the parameters consistent with 11 low energy observables, including the top, bottom, and tau masses. Both boundary conditions have universal scalar masses and "just so" splitting for the up- and down-type Higgs masses. In these models, the third family scalars are lighter than the first two families and the gauginos are lighter than all the scalars. We therefore focus on the gluino phenomenology in these models. In particular, we estimate the lowest allowed gluino mass in our models coming from the most recent LHC data and compare this to limits obtained using simplified models. We find that the lower bound on Mg ˜ in Yukawa-unified SO(10) SUSY GUTs is generically ˜1.2 TEV at the 1? level unless there is considerable degeneracy between the gluino and the lightest supersymmetric particle, in which case the bounds are much weaker. Hence many of our benchmark points are not ruled out by the present LHC data and are still viable models which can be tested at LHC 14.
Coulomb interaction effects on the Majorana states in quantum wires.
Manolescu, A; Marinescu, D C; Stanescu, T D
2014-04-30
The stability of the Majorana modes in the presence of a repulsive interaction is studied in the standard semiconductor wire-metallic superconductor configuration. The effects of short-range Coulomb interaction, which is incorporated using a purely repulsive ?-function to model the strong screening effect due to the presence of the superconductor, are determined within a Hartree-Fock approximation of the effective Bogoliubov-De Gennes Hamiltonian that describes the low-energy physics of the wire. Through a numerical diagonalization procedure we obtain interaction corrections to the single particle eigenstates and calculate the extended topological phase diagram in terms of the chemical potential and the Zeeman energy. We find that, for a fixed Zeeman energy, the interaction shifts the phase boundaries to a higher chemical potential, whereas for a fixed chemical potential this shift can occur either at lower or higher Zeeman energies. These effects can be interpreted as a renormalization of the g-factor due to the interaction. The minimum Zeeman energy needed to realize Majorana fermions decreases with the increasing strength of the Coulomb repulsion. Furthermore, we find that in wires with multi-band occupancy this effect can be enhanced by increasing the chemical potential, i.e. by occupying higher energy bands. PMID:24722427
Projectile structure effects in the collisions 6,7Li+64Zn around the Coulomb barrier.
NASA Astrophysics Data System (ADS)
Figuera, P.; Di Pietro, A.; Fisichella, M.; Lattuada, M.; Maiolino, C.; Milin, M.; Musumarra, A.; Ostashko, V.; Pellegriti, M. G.; Randisi, G.; Santonocito, D.; Scuderi, V.; Strano, E.; Torresi, D.; Zadro, M.
2014-03-01
We measured elastic scattering angular distributions and cross sections for heavy residue production for the systems 6,7Li+64Zn at different energies around the Coulomb barrier. The elastic scattering angular distributions have been reproduced by optical model fits using a renormalized double folding potential for the real and imaginary parts. Absence of usual threshold anomaly in the optical potential was found. The excitation functions for heavy residue production were measured using an activation technique. Comparison with different calculations suggest that complete fusion is the dominant reaction mechanism above the barrier whereas, below the Coulomb barrier, incomplete fusion and transfer dominate.
Coulomb tunneling for fusion reactions in dense matter: Path integral Monte Carlo versus mean field
A. I. Chugunov; H. E. DeWitt; D. G. Yakovlev
2007-07-24
We compare Path Integral Monte Carlo calculations by Militzer and Pollock (Phys. Rev. B 71, 134303, 2005) of Coulomb tunneling in nuclear reactions in dense matter to semiclassical calculations assuming WKB Coulomb barrier penetration through the radial mean-field potential. We find a very good agreement of two approaches at temperatures higher than ~1/5 of the ion plasma temperature. We obtain a simple parameterization of the mean field potential and of the respective reaction rates. We analyze Gamow-peak energies of reacting ions in various reaction regimes and discuss theoretical uncertainties of nuclear reaction rates taking carbon burning in dense stellar matter as an example.
Dynamics of interatomic Coulombic decay in quantum dots
NASA Astrophysics Data System (ADS)
Bande, Annika; Gokhberg, Kirill; Cederbaum, Lorenz S.
2011-10-01
In this work we demonstrate that the interatomic Coulombic decay (ICD), an ultrafast electron relaxation process known for atoms and molecules, is possible in general binding potentials. We used the multiconfiguration time-dependent Hartree method for fermions to study ICD in real time in a two-electron model system of two potential wells. Two decay channels were identified and analyzed by using the box stabilization analysis as well as by evaluating the autocorrelation function and measuring the outgoing electron flux during time-propagations. The total and partial ICD widths of an excited state localized in one potential well as a function of the distance between the two potentials was obtained. Finally, we discuss the results with a view to a possible application of ICD in quantum dot technology.
A Computer Program for Relativistic Multiple Coulomb and Nuclear Excitation
C. A. Bertulani
1998-04-13
A computer program is presented by which one may calculate the multiple electric dipole, electric quadrupole and magnetic dipole Coulomb excitation with relativistic heavy ions. The program applies to an arbitrary nucleus, specified by the spins and energies of the levels and by all E1, E2 and M1 matrix elements. Nuclear excitation is calculated optionally for monopole, dipole and quadrupole excitations and needs inputs of optical potentials. For given bombarding conditions, the differential cross sections and statistical tensors (useful to calculate gamma-ray angular distribution functions) are computed.
Coulomb screening in graphene with topological defects
Baishali Chakraborty; Kumar S. Gupta; Siddhartha Sen
2015-02-20
We analyze the screening of an external Coulomb charge in gapless graphene cone, which is taken as a prototype of a topological defect. In the subcritical regime, the induced charge is calculated using both the Green's function and the Friedel sum rule. The dependence of the polarization charge on the Coulomb strength obtained from the Green's function clearly shows the effect of the conical defect and indicates that the critical charge itself depends on the sample topology. Similar analysis using the Friedel sum rule indicates that the two results agree for low values of the Coulomb charge but differ for the higher strengths, especially in the presence of the conical defect. For a given subcritical charge, the transport cross-section has a higher value in the presence of the conical defect. In the supercritical regime we show that the coefficient of the power law tail of polarization charge density can be expressed as a summation of functions which vary log periodically with the distance from the Coulomb impurity. The period of variation depends on the conical defect. In the presence of the conical defect, the Fano resonances begin to appear in the transport cross-section for a lower value of the Coulomb charge. For both sub and supercritical regime we derive the dependence of LDOS on the conical defect. The effects of generalized boundary condition on the physical observables are also discussed.
Retardation and Coupling to the Sources in Lorenz and Coulomb Gauge
Wundt, B J
2011-01-01
We revisit the calculation of the scalar and vector potentials generated by moving charges and the instantaneous action-at-a-distance solution for the scalar potential in Coulomb gauge, and obtain the Lienard--Wiechert potentials in Coulomb gauge. In [F. Rohrlich, Am. J. Phys. 70, 411 (2002)], it has been shown that the instantaneous form of the integral defining the scalar potential can alternatively be rewritten as an integral involving the retarded Green function with a source term that contains both the longitudinal part of the current as well as the gradient of the charge density. This confirms that the instantaneous formulation of the scalar potential in the Coulomb gauge can be substituted by a retarded integral, if desired. We here verify the identity derived by Rohrlich and provide a second perspective on the problem. Namely, we show that the time derivative of the additional term in the vector potential, which is present only in Coulomb gauge, yields a supplementary contribution to the electric fiel...
"Safe" Coulomb Excitation of 30Mg
O. Niedermaier; H. Scheit; V. Bildstein; H. Boie; J. Fitting; R. von Hahn; F. K"ock; M. Lauer; U. K. Pal; H. Podlech; R. Repnow; D. Schwalm
2004-12-17
We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient gamma spectrometer MINIBALL. Using 30Mg ions accelerated to an energy of 2.25 MeV/u together with a thin nat-Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative de-excitation gamma ray yields the B(E2; 0+ -> 2+) value of 30Mg was determined to be 241(31) e2fm4. Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope 30Mg lies still outside the ``island of inversion''.
Equation of state for magnetized Coulomb plasmas
Potekhin, A Y
2012-01-01
We develop an analytical equation of state (EOS) for magnetized fully ionized plasmas, which cover a wide range of temperatures and densities, from low-density classical plasmas to relativistic, quantum plasma conditions. This EOS directly applies to calculations of structure and evolution of strongly magnetized white dwarfs and neutron stars. We review available analytical and numerical results for thermodynamic functions of the nonmagnetized and magnetized Coulomb gases, liquids, and solids. We propose a new analytical expression for the free energy of solid Coulomb mixtures. Based on recent numerical results, we construct analytical approximations for the thermodynamic functions of harmonic Coulomb crystals in quantizing magnetic fields. The analytical description ensures a consistent evaluation of all astrophysically important thermodynamic functions based on the first, second, and mixed derivatives of the free energy. Our numerical code for calculation of thermodynamic functions based on these approximat...
Baryon asymmetry from leptogenesis with four zero neutrino Yukawa textures
Adhikary, Biswajit; Ghosal, Ambar; Roy, Probir E-mail: ambar.ghosal@saha.ac.in
2011-01-01
The generation of the right amount of baryon asymmetry ? of the Universe from supersymmetric leptogenesis is studied within the type-I seesaw framework with three heavy singlet Majorana neutrinos N{sub i} (i = 1,2,3) and their superpartners. We assume the occurrence of four zeroes in the neutrino Yukawa coupling matrix Y{sub ?}, taken to be ?? symmetric, in the weak basis where N{sub i} (with real masses M{sub i} > 0) and the charged leptons l{sub ?} (? = e,?,?) are mass diagonal. The quadrant of the single nontrivial phase, allowed in the corresponding light neutrino mass matrix m{sub ?}, gets fixed and additional constraints ensue from the requirement of matching ? with its observed value. Special attention is paid to flavor effects in the washout of the lepton asymmetry. We also comment on the role of small departures from high scale ?? symmetry due to RG evolution.
Dynamical fermion mass generation by a strong Yukawa interaction
Brauner, Tomas; Hosek, Jiri
2005-08-15
We consider a model with global Abelian chiral symmetry of two massless fermion fields interacting with a complex massive scalar field. We argue that the Schwinger-Dyson equations for the fermion and boson propagators admit ultraviolet-finite chiral-symmetry-breaking solutions provided the Yukawa couplings are large enough. The fermions acquire masses and the elementary excitations of the complex scalar field are the two real spin-zero particles with different masses. As a necessary consequence of the dynamical chiral symmetry breakdown both in the fermion and scalar sectors, one massless pseudoscalar Nambu-Goldstone boson appears in the spectrum as a collective excitation of both the fermion and the boson fields. Its effective couplings to the fermion and boson fields are calculable.
The effective action in Coulomb gauge QCD
A. Andrasi; J. C. Taylor
2015-03-29
At 2-loop order, Feynman integrals in the Coulomb gauge are divergent over the internal energy variables. Nevertheless, it is known how to calculate the effective action provided that the external gluon fields are all transverse. We show that, for the two-gluon Greens function as an example, the method can be extended to include longitudinal external fields. The longitudinal Greens functions appear in the BRST identities. As an intermediate step, we use a flow gauge, which interpolates between the Feynman and Coulomb gauges.
Coulomb Force as an Entropic Force
Tower Wang
2010-05-17
Motivated by Verlinde's theory of entropic gravity, we give a tentative explanation to Coulomb's law with an entropic force. When trying to do this, we find the equipartition rule should be extended to charges and the concept of temperature should be reinterpreted. If one accepts the holographic principle as well as our generalizations and reinterpretations, then Coulomb's law, the Poisson equation and the Maxwell equations can be derived smoothly. Our attempt can be regarded as a new way to unify the electromagnetic force with gravity, from the entropic origin. Possibly some of our postulates are related to the D-brane picture of black hole thermodynamics.
Hard pion bremsstrahlung in the Coulomb region
Göran Fäldt; Ulla Tengblad
2007-08-02
Hard high-energy pion-nucleus bremsstrahlung, $\\pi^- +A\\to\\pi^- +\\gamma +A$, is studied in the Coulomb region, i.e. the small-angle region where the nuclear scattering is dominated by the Coulomb interaction. Special attention is focussed on the possibility of measuring the pion polarizability in such reactions. We study the sensitivity to the structure of the underlying the pion-Compton amplitude through a model with $\\sigma$, $\\rho$, and a_1 exchanges. It is found that the effective energy in the virtual pion-Compton scattering is often so large that the threshold approximation does not apply.
GUT predictions for quark-lepton Yukawa coupling ratios with messenger masses from non-singlets
Stefan Antusch; Stephen F. King; Martin Spinrath
2015-03-24
We propose new predictions from Grand Unified Theories (GUTs) (applicable to both supersymmetric (SUSY) and non-SUSY models) for the ratios of quark and lepton Yukawa couplings. These new predictions arise from splitting the masses of the messenger fields for the GUT scale Yukawa operators by Clebsch-Gordan factors from GUT symmetry breaking. This has the effect that these factors enter inversely in the predicted quark-lepton Yukawa coupling ratios, leading to new possible GUT predictions. We systematically construct the new predictions that can be realised in this way in SU(5) GUTs and Pati-Salam unified theories and discuss model building applications.
Quantum partner-dance in the 12C + 12C system yields sub-Coulomb fusion resonances
NASA Astrophysics Data System (ADS)
Diaz-Torres, Alexis; Wiescher, Michael
2014-03-01
A preliminary study of the 12C + 12C sub-Coulomb fusion reaction using the time-dependent wave-packet method is presented. The theoretical sub-Coulomb fusion resonances seem to correspond well with observations. The present method might be a more suitable tool for expanding the cross-section predictions towards lower energies than the commonly used potential-model approximation.
BRST invariance in Coulomb gauge QCD
A. Andrasi; J. C. Taylor
2015-07-03
In the Coulomb gauge, the Hamiltonian of QCD contains terms of order h^2, identified by Christ and Lee, which are non-local but instantaneous. The question is addressed how these terms fit in with BRST invariance. Our discussion is confined to the simplest, O(g^4), example.
Thermodynamic Theory of Spherically Trapped Coulomb Clusters
NASA Astrophysics Data System (ADS)
Wrighton, Jeffrey; Dufty, James; Bonitz, Michael; K"{A}Hlert, Hanno
2009-11-01
The radial density profile of a finite number of identical charged particles confined in a harmonic trap is computed over a wide ranges of temperatures (Coulomb coupling) and particle numbers. At low temperatures these systems form a Coulomb crystal with spherical shell structure which has been observed in ultracold trapped ions and in dusty plasmas. The shell structure is readily reproduced in simulations. However, analytical theories which used a mean field approachfootnotetext[1]C. Henning et al., Phys. Rev. E 74, 056403 (2006) or a local density approximationfootnotetext[2]C. Henning et al., Phys. Rev. E 76, 036404 (2007) have, so far, only been able to reproduce the average density profile. Here we present an approach to Coulomb correlations based on the hypernetted chain approximation with additional bridge diagrams. It is demonstrated that this model reproduces the correct shell structure within a few percent and provides the basis for a thermodynamic theory of Coulomb clusters in the strongly coupled fluid state.footnotetext[3]J. Wrighton, J.W. Dufty, H. K"ahlert and M. Bonitz, J. Phys. A 42, 214052 (2009) and Phys. Rev. E (2009) (to be submitted)
Spherical volume averages of static electric and magnetic fields using Coulomb and Biot-Savart laws
Ben Yu-Kuang Hu
2009-01-31
We present derivations of the expressions for the spherical volume averages of static electric and magnetic fields that are virtually identical. These derivations utilize the Coulomb and Biot-Savart laws, and make no use of vector calculus identities or potentials.
If Coulomb's law were not inverse square: The charge distribution inside a solid conducting sphere
NASA Astrophysics Data System (ADS)
Spencer, Ross L.
1990-04-01
The distribution of charge between concentric conducting shells has been at the heart of the most sensitive tests of the exponent in Coulomb's law since the days of Henry Cavendish. But it appears that no one has ever answered the question of how an excess of charge would distribute itself throughout the interior of a solid conductor if Coulomb's law were other than inverse square. Spherically symmetric solutions to this problem have been found under the assumption that the potential of a point charge varies either as e-kr/r or as 1/rn.
Tunable Coulomb blockade and giant Coulomb blockade magnetoresistance in a double quantum dot array
Zhang, Xiaoguang; Xiang, T.
2011-01-01
We propose a Hubbard model to illuminate the tunneling effect of electrons in a double quantum dot array connected in the parallel circuit configuration to electrodes. The change in the interdot coupling is shown to dramatically influence the Coulomb blockade properties, consistent with earlier experimental observations. For magnetic double dots, the interdot coupling can be tuned by the external magnetic field, leading to a giant Coulomb blockade magnetoresistance.
Coulomb drag in high Landau levels I. V. Gornyi,1,
von Oppen, Felix
Coulomb drag in high Landau levels I. V. Gornyi,1, * A. D. Mirlin,1,2, and F. von Oppen3,4 1 December 2004) Recent experiments on Coulomb drag in the quantum Hall regime have yielded a number of surprises. The most striking observations are that the Coulomb drag can become negative in high Landau
Reconciling Coulomb Dissociation and Radiative Capture Measurements H. Esbensen,1
Bertsch George F.
Reconciling Coulomb Dissociation and Radiative Capture Measurements H. Esbensen,1 G. F. Bertsch,2) We calculate the energy spectrum for 8B dissociation on a Pb target to all orders in the Coulomb and nuclear fields, and show that the slope of S17E obtained in previous analyses of Coulomb dissociation data
Stability of the three-dimensional Coulomb friction law
Barber, James R.
Stability of the three-dimensional Coulomb friction law By Hanbum C h o and J. R. Barber Department of solution in quasi- static contact problems involving large coefficients of Coulomb friction. This paper that can make contact with a rigid Coulomb friction support. A critical coefficient of friction
Bond alternation in the infinite polyene: effect of long range Coulomb interactions
Mazumdar, S.; Campbell, D.K.
1985-01-01
We investigate the effects of long-range Coulomb interactions on bond and site dimerizations in a one-dimensional half-filled band. It is shown that the ground state broken symmetry is determined by two sharp inequalities involving the Coulomb parameters. Broken symmetry with periodicity 2k/sub F/ is guaranteed only if the first inequality (downward convexity of the intersite potential) is obeyed, while the second inequality gives the phase boundary between the bond-dimerized and site-dimerized phases. Application of these inequalities to the Pariser-Parr-Pople model for linear polyenes shows that the infinite polyene has enhanced bond alternation for both Ohno and Mataga-Nishimoto parametrizations of the intersite Coulomb terms. The possible role of distant neighbor interactions in photogeneration experiments is discussed. 26 refs., 3 figs.
The impact of sharp screening on the Coulomb scattering problem in three dimensions
S L Yakovlev; M V Volkov; E Yarevsky; N Elander
2010-03-01
The scattering problem for two particles interacting via the Coulomb potential is examined for the case where the potential has a sharp cut-off at some distance. The problem is solved for two complimentary situations, firstly when the interior part of the Coulomb potential is left in the Hamiltonian and, secondly, when the long range tail is considered as the potential. The partial wave results are summed up to obtain the wave function in three dimensions. It is shown that in the domains where the wave function is expected to be proportional to the known solutions, the proportionality is given by an operator acting on the angular part of the wave function. The explicit representation for this operator is obtained in the basis of Legendre polynomials. We proposed a driven Schr\\"odinger equation including an inhomogeneous term of the finite range with purely outgoing asymptotics for its solution in the case of the three dimensional scattering problem with long range potentials.
CP invariance of chiral gauge theories and Majorana-Yukawa couplings on the lattice
Yuji Igarashi; Jan M. Pawlowski
2009-11-11
The construction of CP-invariant lattice chiral gauge theories and the construction of lattice Majorana fermions with chiral Yukawa couplings is subject to topological obstructions. In the present work we suggest lattice extensions of charge and parity transformation for Weyl fermions. This enables us to construct lattice chiral gauge theories that are CP invariant. For the construction of Majorana-Yukawa couplings, we discuss two models with symplectic Majorana fermions: a model with two symplectic doublets, and one with an auxiliary doublet.
Induced Light-Quark Yukawa Couplings as a probe of Low-Energy Dynamics in QCD
M. R. Ahmady; V. Elias; A. H. Fariborz; R. R. Mendel
1996-04-02
We examine the heavy-quark-induced Yukawa interaction between light quarks and a light Higgs field, which is facilitated in the chiral limit by the dynamical mass of light quarks anticipated from the chiral-noninvariance of the QCD vacuum. A low-energy estimate of the strong coupling near unity can be obtained from a comparison of the explicit perturbative calculation of the induced Yukawa interaction at zero momentum to a Higgs-low-energy theorem prediction for the same interaction.
Pore fluid pressure, apparent friction, and Coulomb failure
Beeler, N.M.; Simpson, R.W.; Hickman, S.H.; Lockner, D.A.
2000-01-01
Many recent studies of stress-triggered seismicity rely on a fault failure model with a single free parameter, the apparent coefficient of friction, presumed to be a material constant with possible values 0 ? ?? ? 1. These studies may present a misleading view of fault strength and the role of pore fluid pressure in earthquake failure. The parameter ?? is intended to incorporate the effects of both friction and pore pressure, but is a material constant only if changes in pore fluid pressure induced by changes in stress are proportional to the normal stress change across the potential failure plane. Although specific models of fault zones permit such a relation, neither is it known that fault zones within the Earth behave this way, nor is this behavior expected in all cases. In contrast, for an isotropic homogeneous poroelastic model the pore pressure changes are proportional to changes in mean stress, ?? is not a material constant, and ?? ? ?? ? +?. Analysis of the change in Coulomb failure stress for tectonically loaded reverse and strike-slip faults shows considerable differences between these two pore pressure models, suggesting that such models might be distinguished from one another using observations of triggered seismicity (e.g., aftershocks). We conclude that using the constant apparent friction model exclusively in studies of Coulomb failure stress is unwise and could lead to significant errors in estimated stress change and seismic hazard.
SUSY-Yukawa Sum Rule at the LHC
Monika Blanke; David Curtin; Maxim Perelstein
2010-08-03
We propose the "supersymmetric (SUSY) Yukawa sum rule", a relationship between physical masses and mixing angles of the third-generation quarks and squarks. The sum rule follows directly from a relation between quark and squark couplings to the Higgs, enforced by SUSY. It is exactly this relation that ensures the cancellation of the one-loop quadratic divergence in the Higgs mass from the top sector. Testing the sum rule experimentally would thus provide a powerful consistency check on SUSY as the solution to the gauge hierarchy problem. While such a test will most likely have to await a future next-generation lepton collider, the LHC experiments may be able to make significant progress towards this goal. If some of the terms entering the sum rule are measured at the LHC, the sum rule can be used (within SUSY framework) to put interesting constraints on the other terms, such as the mixing angles among third-generation squarks. We outline how the required mass measurements could be performed, and estimate the accuracy that can be achieved at the LHC.
Fermionic dark matter with pseudo-scalar Yukawa interaction
Ghorbani, Karim
2015-01-01
We consider a renormalizable extension of the standard model whose fermionic dark matter (DM) candidate interacts with a real singlet pseudo-scalar via a pseudo-scalar Yukawa term while we assume that the full Lagrangian is CP-conserved in the classical level. When the pseudo-scalar boson develops a non-zero vacuum expectation value, spontaneous CP-violation occurs and this provides a CP-violated interaction of the dark sector with the SM particles through mixing between the Higgs-like boson and the SM-like Higgs boson. This scenario suggests a minimal number of free parameters. Focusing mainly on the indirect detection observables, we calculate the dark matter annihilation cross section and then compute the DM relic density in the range up to m{sub DM} = 300 GeV.We then find viable regions in the parameter space constrained by the observed DM relic abundance as well as invisible Higgs decay width in the light of 125 GeV Higgs discovery at the LHC. We find that within the constrained region of the parameter space, there exists a model with dark matter mass m{sub DM} ? 38 GeV annihilating predominantly into b quarks, which can explain the Fermi-LAT galactic gamma-ray excess.
Constraining the charm Yukawa and Higgs-quark coupling universality
NASA Astrophysics Data System (ADS)
Perez, Gilad; Soreq, Yotam; Stamou, Emmanuel; Tobioka, Kohsaku
2015-08-01
We introduce four different types of data-driven analyses with different levels of robustness that constrain the size of the Higgs-charm Yukawa coupling: (i) Recasting the vector-boson associated V h analyses that search for the bottom-pair final state. We use this mode to directly and model independently constrain the Higgs-to-charm coupling, yc/ycSM?234 . (ii) The direct measurement of the total width, yc/ycSM?120 - 140 . (iii) The search for h ?J /? ? , yc/ycSM?220 . (iv) A global fit to the Higgs signal strengths, yc/ycSM?6.2 . A comparison with t t ¯h data allows us to show that the Higgs does not couple to quarks in a universal way, as is expected in the Standard Model. Finally, we demonstrate how the experimental collaborations can further improve our direct bound by roughly an order of magnitude by charm tagging, as is already used in new-physics searches.
Non-commutative relativistic equation with a Coulomb potential
Zaim, Slimane; Khodja, Lamine; Delenda, Yazid
2012-06-27
We improve the previous study of the Klein-Gordon equation in a non-commutative space-time as applied to the Hydrogen atom to extract the energy levels, by considering the secondorder corrections in the non-commutativity parameter. Phenomenologically we show that noncommutativity plays the role of spin.
The one dimensional Coulomb lattice fluid capacitor
Vincent Demery; David S. Dean; Thomas C. Hammant; Ronald R. Horgan; Rudolf Podgornik
2012-06-21
The one dimensional Coulomb lattice fluid in a capacitor configuration is studied. The model is formally exactly soluble via a transfer operator method within a field theoretic representation of the model. The only interactions present in the model are the one dimensional Coulomb interaction between cations and anions and the steric interaction imposed by restricting the maximal occupancy at any lattice site to one particle. Despite the simplicity of the model, a wide range of intriguing physical phenomena arise, some of which are strongly reminiscent of those seen in experiments and numerical simulations of three dimensional ionic liquid based capacitors. Notably we find regimes where over-screening and density oscillations are seen near the capacitor plates. The capacitance is also shown to exhibit strong oscillations as a function of applied voltage. It is also shown that the corresponding mean field theory misses most of these effects. The analytical results are confirmed by extensive numerical simulations.
Ferromagnetic Coulomb phase in classical spin ice
NASA Astrophysics Data System (ADS)
Powell, Stephen
2015-03-01
Spin ice is a frustrated magnetic system that at low temperatures exhibits a Coulomb phase, a classical spin liquid with topological order and deconfined excitations. This work establishes the presence of a Coulomb phase with coexisting ferromagnetic order in a microscopic model of classical spin ice subject to uniaxial lattice distortion. General theoretical arguments are presented for the presence of such a phase, and its existence is confirmed using Monte Carlo results. This example is used to illustrate generic properties of spin liquids with magnetic order, including deconfinement of monopoles, signatures in the neutron-scattering structure factor, and critical behavior at phase transitions. An analogous phase, a superfluid with spontaneously broken particle-hole symmetry, is demonstrated in a model of hard-core lattice bosons, related to spin ice through the quantum-classical correspondence.
Coulomb explosion of uniformly charged spheroids
NASA Astrophysics Data System (ADS)
Grech, M.; Nuter, R.; Mikaberidze, A.; di Cintio, P.; Gremillet, L.; Lefebvre, E.; Saalmann, U.; Rost, J. M.; Skupin, S.
2011-11-01
A simple, semianalytical model is proposed for nonrelativistic Coulomb explosion of a uniformly charged spheroid. This model allows us to derive the time-dependent particle energy distributions. Simple expressions are also given for the characteristic explosion time and maximum particle energies in the limits of extreme prolate and oblate spheroids as well as for the sphere. Results of particle simulations are found to be in remarkably good agreement with the model.
Coulomb collision effects on linear Landau damping
Callen, J. D.
2014-05-15
Coulomb collisions at rate ? produce slightly probabilistic rather than fully deterministic charged particle trajectories in weakly collisional plasmas. Their diffusive velocity scattering effects on the response to a wave yield an effective collision rate ?{sub eff} ? ? and a narrow dissipative boundary layer for particles with velocities near the wave phase velocity. These dissipative effects produce temporal irreversibility for times t???1/?{sub eff} during Landau damping of a small amplitude Langmuir wave.
Perturbation theory in the Hamiltonian approach to Yang-Mills theory in Coulomb gauge
Campagnari, Davide R.; Reinhardt, Hugo; Weber, Axel
2009-07-15
We study the Hamiltonian approach to Yang-Mills theory in Coulomb gauge in Rayleigh-Schroedinger perturbation theory. The static gluon and ghost propagator as well as the potential between static color sources are calculated to one-loop order. Furthermore, the one-loop {beta} function is calculated from both the ghost-gluon vertex and the static potential and found to agree with the result of covariant perturbation theory.
Coulomb explosion of large penetrating molecular clusters
Wegner, H.E.; Thieberger, P.
1981-01-01
The main purpose of these Coulomb explosion measurements is to determine what kind of structure these and other complex molecules may have and also to determine what other special phenomena may come into play as these complex molecules pass through matter. Although the first preliminary measurements involving the Coulomb explosion of these molecules was reported at this workshop last year, the results are briefly summarized before going on to the more recent measurements obtained with a completely new kind of detector system. This new image intensifier detector system, coupled with a microcomputer, has proven to be a valuable tool in the study of the Coulomb explosion of complex molecules that penetrate matter. In the future, with some additional improvements in the system, and much better statistics for most of the molecules studied to date, it is expected that much new information will be gained about the structure of many kinds of complex molecular ions including the special effects that may be encountered when these fast molecular ions penetrate matter.
The interplay of nuclear and Coulomb effects in proton breakup from exotic nuclei
Kumar, Ravinder
2012-01-01
This paper gives new insight to the study of dynamical effects in proton breakup as compared to neutron breakup from a weakly bound state in an exotic nucleus. Following our recent work [Ravinder Kumar and Angela Bonaccorso, Phys. Rev. C84 014613 (2011)] there has been some discussion in the literature [B. Paes, J. Lubiana, P.R.S. Gomes, V. Guimar\\~aes, Nucl. Phys. A890 1 (2012); Y. Kucuk and A. M. Moro, Phys. Rev. C86 034601 (2012)], thus in order to clarify and asses quantitatively which mechanism would dominate measured observables, we study here several reaction mechanisms separately but also their total including interference. These mechanisms are: the recoil effect of the core-target Coulomb potential which we distinguish from the direct proton-target Coulomb potential and nuclear breakup, which consists of stripping and diffraction. Direct Coulomb breakup typically gives cross sections about an order of magnitude larger than the recoil term and the amount of nuclear diffraction vs. Coulomb depends on t...
Z. Papp; W. Plessas
1996-04-18
We demonstrate the feasibility and efficiency of the Coulomb-Sturmian separable expansion method for generating accurate solutions of the Faddeev equations. Results obtained with this method are reported for several benchmark cases of bosonic and fermionic three-body systems. Correct bound-state results in agreement with the ones established in the literature are achieved for short-range interactions. We outline the formalism for the treatment of three-body Coulomb systems and present a bound-state calculation for a three-boson system interacting via Coulomb plus short-range forces. The corresponding result is in good agreement with the answer from a recent stochastic-variational-method calculation.
Structure of multi-component/multi-Yukawa mixtures
NASA Astrophysics Data System (ADS)
Blum, L.; Arias, M.
2006-09-01
Recent small angle scattering experiments reveal new peaks in the structure function S(k) of colloidal systems (Liu et al 2005 J. Chem. Phys. 122 044507), in a region that was inaccessible with older instruments. It has been increasingly evident that a single (or double) Yukawa MSA-closure cannot account for these observations, and three or more terms are needed. On the other hand the MSA is not sufficiently accurate (Broccio et al 2005 Preprint); more accurate theories such as the HNC have been tried. But while the MSA is asymptotically exact at high densities (Rosenfield and Blum 1986 J. Chem. Phys. 85 1556), it does not satisfy the low density asymptotics. This has been corrected in the soft MSA (Blum et al 1972 J. Chem. Phys. 56 5197, Narten et al 1974 J. Chem. Phys. 60 3378) by adding exponential type terms. The results compared to experiment and simulation for liquid sodium by Rahman and Paskin (as shown in Blum et al 1972 J. Chem. Phys. 56 5197) are remarkably good. We use here a general closure of the Ornstein-Zernike equation, which is not necessarily the MSA closure (Blum and Hernando 2001 Condensed Matter Theories vol 16 ed Hernandez and Clark (New York: Nova) p 411). \\begin{equation} \\fl c_{ij}(r)=\\sum_{n=1}^{M}{\\cal{K}}_{ij}^{(n)}\\rme^{-z_{n}r}/r\\tqs {\\cal{K}}_{ij}^{(n)}=K^{(n)}\\delta_{i}^{(n)}\\delta_{j}^{(n)}\\tqs r\\geq \\sigma_{ij} \\label{eq1} \\end{equation} with the boundary condition for gij(r) = 0 for r<=?ij. This general closure of the Ornstein-Zernike equation will go well beyond the MSA since it has been tested by Monte Carlo simulation for tetrahedral water (Blum et al 1999 Physica A 265 396), toroidal ion channels (Enriquez and Blum 2005 Mol. Phys. 103 3201) and polyelectrolytes (Blum and Bernard 2004 Proc. Int. School of Physics Enrico Fermi, Course CLV vol 155, ed Mallamace and Stanley (Amsterdam: IOS Press) p 335). For this closure we get for the Laplace transform of the pair correlation function an explicitly symmetric result \\begin{equation} \\fl 2 \\pi \\tilde{g}_{ij}(s)=-\\frac{\\rme^{-s \\sigma_{ij}}}{D_{\\tau}(s)} \\left\\{{1\\over s^2}+{1\\over s}Q^{\\prime}_{ij}(\\sigma_{ij})+\\sum_{m=1}^{M}{{ z_m \\tilde{\\cal{X}}}_i^{(m)}{f}_j^{(m)}\\over{s+z_m}}\\right\\}. \\label{eq2} \\end{equation} This function is also easily transformed into S(k) by replacing s\\Rightarrow \\rmi k . For low density situations (dilute colloids) D_{\\tau } (s)\\sim 1+{\\cal {O}(\\rho)} and S(k) is a sum of M Lorentzians. For hard sphere PY mixtures we get the simple (compare Lebowitz 1964 Phys. Rev. 133 A895 and Blum and Stell 1979 J. Chem. Phys. 71 42) \\[ 2 \\pi \\tilde{g}_{ij}(s)=-\\frac{\\rme^{-s \\sigma_{ij}}}{s^2 D_{\\tau}(s)} \\left\\{1+s\\left[(Q^{HS})^{\\prime}_{ij}(\\sigma_{ij})\\right]\\right\\} \\] where D?(s) is a scalar function. For polydisperse electrolytes in the MSA a simpler expression is also obtained (compare Blum and Hoye 1977 J. Phys. Chem. 81 1311). An explicit continued fraction solution of the one component multi-Yukawa case is also given.
Coulomb gauge confinement in the heavy quark limit
Popovici, C.; Watson, P.; Reinhardt, H.
2010-05-15
The relationship between the nonperturbative Green's functions of Yang-Mills theory and the confinement potential is investigated. By rewriting the generating functional of quantum chromodynamics in terms of a heavy quark mass expansion in Coulomb gauge, restricting to leading order in this expansion and considering only the two-point functions of the Yang-Mills sector, the rainbow-ladder approximation to the gap and Bethe-Salpeter equations is shown to be exact in this case and an analytic, nonperturbative solution is presented. It is found that there is a direct connection between the string tension and the temporal gluon propagator. Further, it is shown that for the 4-point quark correlation functions, only confined bound states of color-singlet quark-antiquark (meson) and quark-quark (baryon) pairs exist.
Reaction Dynamics of Light Nuclei Around the Coulomb Barrier
NASA Astrophysics Data System (ADS)
Di Pietro, Alessia; Fernandez Garcia, Juan Pablo; Figuera, Pierpaolo; Fisichella, Maria; Lattuada, Marcello; Zadro, Mile
The reaction dynamics of collisions involving halo or weakly bound nuclei, at energies around the Coulomb barrier, can be strongly affected by the structure of the colliding nuclei. Very strong entrance channel effects have been observed on various reaction processes such as, elastic scattering, fusion and direct reactions, when comparing collisions induced by halo nuclei with the ones induced on the same target by their cores. Collisions induced by the stable weakly bound nuclei 6Li, 7Li show also some peculiarities in comparison to the ones induced by well bound nuclei, such as absence of usual threshold anomaly in the optical potential and strong competition of complete fusion with incomplete fusion and transfer in the heavy residue production cross-sections. In this contribution an overview of our present understanding of these topics will be given.
Finsler-type modification of the Coulomb law
Yakov Itin; Claus Lämmerzahl; Volker Perlick
2014-12-29
Finsler geometry is a natural generalization of pseudo-Riemannian geometry. It can be motivated e.g. by a modified version of the Ehlers-Pirani-Schild axiomatic approach to space-time theory. Also, some scenarios of quantum gravity suggest a modified dispersion relation which could be phrased in terms of Finsler geometry. On a Finslerian spacetime, the Universality of Free Fall is still satisfied but Local Lorentz Invariance is violated in a way not covered by standard Lorentz Invariance Violation schemes. In this paper we consider a Finslerian modification of Maxwell's equations. The corrections to the Coulomb potential and to the hydrogen energy levels are computed. We find that the Finsler metric corrections yield a splitting of the energy levels. Experimental data provide bounds for the Finsler parameters.
Finsler-type modification of the Coulomb law
NASA Astrophysics Data System (ADS)
Itin, Yakov; Lämmerzahl, Claus; Perlick, Volker
2014-12-01
Finsler geometry is a natural generalization of pseudo-Riemannian geometry. It can be motivated e.g. by a modified version of the Ehlers-Pirani-Schild axiomatic approach to space-time theory. Also, some scenarios of quantum gravity suggest a modified dispersion relation which could be phrased in terms of Finsler geometry. On a Finslerian space-time, the universality of free fall is still satisfied but local Lorentz invariance is violated in a way not covered by standard Lorentz invariance violation schemes. In this paper we consider a Finslerian modification of Maxwell's equations. The corrections to the Coulomb potential and to the hydrogen energy levels are computed. We find that the Finsler metric corrections yield a splitting of the energy levels. Experimental data provide bounds for the Finsler parameters.
Oscillator-Morse-Coulomb mappings and algebras for constant or position-dependent mass
C. Quesne
2008-02-27
The bound-state solutions and the su(1,1) description of the $d$-dimensional radial harmonic oscillator, the Morse and the $D$-dimensional radial Coulomb Schr\\"odinger equations are reviewed in a unified way using the point canonical transformation method. It is established that the spectrum generating su(1,1) algebra for the first problem is converted into a potential algebra for the remaining two. This analysis is then extended to Schr\\"odinger equations containing some position-dependent mass. The deformed su(1,1) construction recently achieved for a $d$-dimensional radial harmonic oscillator is easily extended to the Morse and Coulomb potentials. In the last two cases, the equivalence between the resulting deformed su(1,1) potential algebra approach and a previous deformed shape invariance one generalizes to a position-dependent mass background a well-known relationship in the context of constant mass.
Oscillator-Morse-Coulomb mappings and algebras for constant or position-dependent mass
Quesne, C.
2008-02-15
The bound-state solutions and the su(1,1) description of the d-dimensional radial harmonic oscillator, the Morse, and the D-dimensional radial Coulomb Schroedinger equations are reviewed in a unified way using the point canonical transformation method. It is established that the spectrum generating su(1,1) algebra for the first problem is converted into a potential algebra for the remaining two. This analysis is then extended to Schroedinger equations containing some position-dependent mass. The deformed su(1,1) construction recently achieved for a d-dimensional radial harmonic oscillator is easily extended to the Morse and Coulomb potentials. In the last two cases, the equivalence between the resulting deformed su(1,1) potential algebra approach and a previous deformed shape invariance one generalizes to a position-dependent mass background a well-known relationship in the context of constant mass.
"Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications
NASA Astrophysics Data System (ADS)
Marshall, J. R.
1999-09-01
The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this very brief (30-60 sec) damping period, motion of the grains was observed to be retarded by the electrostatic interactions. The fact that the grains almost instantly formed aggregates was evidence that their ballistic motions had been constrained and redirected by the dipole-dipole interactions that led to filamentary aggregate development. Undoubtedly, the "Coulombic viscosity" of the cloud assisted in damping grain motion so rapidly. The electrostatically-induced grain-cloud viscosity or drag exerted on grain motion, is a complex function of three major parameters: charge magnitude, charge sign, and mean intergranular distance. The above experiments illustrate one particular type of granular behavior. The discussion here will therefore be restricted to drag relationships: (a) between grains that are naturally charged triboelectrically and thus exhibit dipole-dipole attractions between one another even if there are slight net charges present (which can be overwhelmed by dipole coupling at short distances), and (b) between grains that are densely spaced where the intergranular distance varies between zero and some value (usually tens or hundreds of grain diameters) that permits each grain to detect the dipole moment of another grain -- the distance is not so great that other grains appears as neutral electrical "singularities. I. Aeolian transport: During motion of grains in a saltation cloud (on Earth, Mars, or Venus), triboelectric charging must occur as a result of multiple grain contacts, and by friction with the entraining air. A situation might develop that is similar to the one described above in the attrition device: grain motion becoming significantly retarded (reduced flux) as grains find it increasingly difficult to either separate from the surface, or to pass one another without Coulombic retarding forces. A "Coulombic drag" will exist at flux initiation and increase with time to work in direct opposition to the aerodynamic drag that drives the grain motion. It is predicted that this will lead to an incr
"Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications
NASA Technical Reports Server (NTRS)
Marshall, J. R.
1999-01-01
The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this very brief (30-60 sec) damping period, motion of the grains was observed to be retarded by the electrostatic interactions. The fact that the grains almost instantly formed aggregates was evidence that their ballistic motions had been constrained and redirected by the dipole-dipole interactions that led to filamentary aggregate development. Undoubtedly, the "Coulombic viscosity" of the cloud assisted in damping grain motion so rapidly. The electrostatically-induced grain-cloud viscosity or drag exerted on grain motion, is a complex function of three major parameters: charge magnitude, charge sign, and mean intergranular distance. The above experiments illustrate one particular type of granular behavior. The discussion here will therefore be restricted to drag relationships: (a) between grains that are naturally charged triboelectrically and thus exhibit dipole-dipole attractions between one another even if there are slight net charges present (which can be overwhelmed by dipole coupling at short distances), and (b) between grains that are densely spaced where the intergranular distance varies between zero and some value (usually tens or hundreds of grain diameters) that permits each grain to detect the dipole moment of another grain -- the distance is not so great that other grains appears as neutral electrical "singularities. I. Aeolian transport: During motion of grains in a saltation cloud (on Earth, Mars, or Venus), triboelectric charging must occur as a result of multiple grain contacts, and by friction with the entraining air. A situation might develop that is similar to the one described above in the attrition device: grain motion becoming significantly retarded (reduced flux) as grains find it increasingly difficult to either separate from the surface, or to pass one another without Coulombic retarding forces. A "Coulombic drag" will exist at flux initiation and increase with time to work in direct opposition to the aerodynamic drag that drives the grain motion. It is predicted that this will lead to an increase
Quasi-localized wavefunctions on magnetized tori and tiny neutrino Yukawa couplings
Keigo Sumita
2015-09-11
This paper shows that, a quasi-localization of wavefunctions in toroidal compactifications with magnetic fluxes can lead to a strong suppression for relevant Yukawa couplings, and it is applicable to obtain tiny neutrino masses. Although it is known that magnetic fluxes lead to a Gaussian profile of zero-modes on a torus and that can yield a suppressed coupling in higher-dimensional supersymmetric Yang-Mills (SYM) theories, the largest (diagonal) entry of Yukawa matrices is always of $\\mathcal O(1)$. In this paper, we propose a way to induce an absolutely tiny global factor of Yukawa matrices. In two SYM theories defined in different dimensional spacetime, their bifundamental representations must be localized as a point in some directions. Overlaps of such point-like localized wavefunctions and Gaussian zero-modes give a global factor of Yukawa matrices, and it can be a strong suppression factor or a usual $\\mathcal O(1)$ factor, corresponding to their distance. Our numerical analysis shows that it is possible to obtain a suppression strong enough to realize the tiny neutrino masses without a hard fine-tuning. Furthermore, we propose a concrete model of the tiny neutrino Yukawa couplings in a magnetized SYM system.
Structure Effects on Coulomb Dissociation of $^8$B
F. M. Nunes; R. Shyam; I. J. Thompson
1998-05-23
Coulomb Dissociation provides an alternative method for determining the radiative capture cross sections at astrophysically relevant low relative energies. For the breakup of $^8$B on $^{58}$Ni, we calculate the total Coulomb Dissociation cross section and the angular distribution for E1, E2 and M1. Our calculations are performed first within the standard first order semiclassical theory of Coulomb Excitation, including the correct three body kinematics, and later including the projectile-target nuclear interactions.
Coulomb Repulsion in Miniature Ion Mobility Spectrometry
Xu, J.; Whitten, W.B.; Ramsey, J.M.
1999-08-08
We have undertaken a study of ion mobility resolution in a miniature ion mobility spectrometer with a drift channel 1.7 mm in diameter and 35 mm in length. The device attained a maximum resolution of 14 in separating ions of NO, O{sub 2}, and methyl iodine. The ions were generated by pulses from a frequency-quadrupled Nd:YAG laser. Broadening due to Coulomb repulsion was modeled theoretically and shown experimentally to have a major effect on the resolution of the miniature device.
Quenching molecular photodissociation by intermolecular Coulombic decay
NASA Astrophysics Data System (ADS)
Kopelke, S.; Chiang, Y.-C.; Gokhberg, K.; Cederbaum, L. S.
2012-07-01
In this paper we study the impact of interatomic Coulombic decay (ICD) on molecular photodissociation. The investigation reveals the hitherto unrecognized ability of ICD to quench processes involving nuclear rearrangements. Numerical computations of the nuclear dynamics, initiated by photoexciting the B1?+ Rydberg state of CO in CO.Mg complexes, are carried out. The efficiencies of ICD and photoinduced predissociation are compared for the four lowest vibrational levels of the corresponding electronic state. We also show the impact of CO vibrations on the ICD electron spectrum. Finally, we discuss the growing efficiency of ICD to quench the dissociation as the number of neighboring Mg atoms is increased.
Effect of Coulomb interaction on multi-electronwave packet dynamics
Shiokawa, T.; Takada, Y.; Konabe, S.; Hatsugai, Y.; Muraguchi, M.; Endoh, T.; Shiraishi, K.
2013-12-04
We have investigated the effect of Coulomb interaction on electron transport in a one-dimensional nanoscale structure using a multi-electron wave packet approach. To study the time evolution, we numerically solve the time-dependent Hartree-Fock equation, finding that the electron wave packet dynamics strongly depends on the Coulomb interaction strength. When the Coulomb interaction is large, each electron wave packet moves separately in the presence of an electric field. With weak Coulomb interaction, however, the electron wave packets overlap, forming and moving as one collective wave packet.
Lattice study of the Higgs-Yukawa model in and beyond the Standard Model
David Y. -J. Chu; Karl Jansen; Bastian Knippschild; C. -J. David Lin; Kei-Ichi Nagai; Attila Nagy
2015-11-02
We derive finite-size scaling formulae for four-dimensional Higgs-Yukawa models near the Gaussian fixed point. These formulae will play an essential role in future, detailed investigation of such models. In particular, they can be used to determine the nature of the observed phase transitions, and confirm or rule out the possibility of having non-trivial fixed points in the Higgs-Yukawa models. Our scaling formula for Binder's cumulant is tested against lattice simulations carried out at weak couplings, and good agreement is found. As a separate project, we also present preliminary results from our study of a chirally-invariant Higgs-Yukawa model including a dimension-six operator at finite temperature. Our work provides first indications of first-order temperature-induced phase transitions near the infinite cutoff limit in this model.
Lattice study of the Higgs-Yukawa model in and beyond the Standard Model
Chu, David Y -J; Knippschild, Bastian; Lin, C -J David; Nagai, Kei-Ichi; Nagy, Attila
2015-01-01
We derive finite-size scaling formulae for four-dimensional Higgs-Yukawa models near the Gaussian fixed point. These formulae will play an essential role in future, detailed investigation of such models. In particular, they can be used to determine the nature of the observed phase transitions, and confirm or rule out the possibility of having non-trivial fixed points in the Higgs-Yukawa models. Our scaling formula for Binder's cumulant is tested against lattice simulations carried out at weak couplings, and good agreement is found. As a separate project, we also present preliminary results from our study of a chirally-invariant Higgs-Yukawa model including a dimension-six operator at finite temperature. Our work provides first indications of first-order temperature-induced phase transitions near the infinite cutoff limit in this model.
Self-Consistent Monte Carlo Study of the Coulomb Interaction under Nano-Scale Device Structures
NASA Astrophysics Data System (ADS)
Sano, Nobuyuki
2011-03-01
It has been pointed that the Coulomb interaction between the electrons is expected to be of crucial importance to predict reliable device characteristics. In particular, the device performance is greatly degraded due to the plasmon excitation represented by dynamical potential fluctuations in high-doped source and drain regions by the channel electrons. We employ the self-consistent 3D Monte Carlo (MC) simulations, which could reproduce both the correct mobility under various electron concentrations and the collective plasma waves, to study the physical impact of dynamical potential fluctuations on device performance under the Double-gate MOSFETs. The average force experienced by an electron due to the Coulomb interaction inside the device is evaluated by performing the self-consistent MC simulations and the fixed-potential MC simulations without the Coulomb interaction. Also, the band-tailing associated with the local potential fluctuations in high-doped source region is quantitatively evaluated and it is found that the band-tailing becomes strongly dependent of position in real space even inside the uniform source region. This work was partially supported by Grants-in-Aid for Scientific Research B (No. 2160160) from the Ministry of Education, Culture, Sports, Science and Technology in Japan.
Upper Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model
P. Gerhold; K. Jansen
2010-02-23
We establish the cutoff-dependent upper Higgs boson mass bound by means of direct lattice computations in the framework of a chirally invariant lattice Higgs-Yukawa model emulating the same chiral Yukawa coupling structure as in the Higgs-fermion sector of the Standard Model. As expected from the triviality picture of the Higgs sector, we observe the upper mass bound to decrease with rising cutoff parameter $\\Lambda$. Moreover, the strength of the fermionic contribution to the upper mass bound is explored by comparing to the corresponding analysis in the pure $\\Phi^4$-theory.
Nonlinear instability of the one-dimensional Vlasov-Yukawa system
Ha, Seung-Yeal; Lee, Ho; Ha, Taeyoung; Hwang, Chi-Ok
2011-03-15
We discuss the nonlinear instability of some class of stationary solutions to the one-dimensional Vlasov-Yukawa system with a mass parameter m. The Vlasov-Yukawa system corresponds to the short-range correction of the repulsive Vlasov-Poisson system arising from plasma physics. We show that the stationary solutions satisfying the Penrose condition are nonlinearly unstable in small mass regime. In a large mass regime, the massiveness of force carrier particles acts as stabilizer in a finite time interval. We present several numerical results to confirm our analytical results.
Low-density crystals in charged colloids : Comparison with Yukawa theory
Ioatzin Ríos de Anda; Antonia Statt; Francesco Turci; C. Patrick Royall
2015-01-08
Charged colloids can behave as Yukawa systems, with similar phase behaviour. Using particle- resolved studies, we consider a system with an unusually long Debye screening length which forms crystals at low colloid volume fraction {\\phi} ~ 0.01. We quantitatively compare this system with the Yukawa model and find that its freezing point is compatible with the theoretical prediction but that the crystal polymorph is not always that expected. In particular we find body-centred cubic crystals where face-centred cubic crystals are expected.
Thermal spin current through a double quantum dot molecular junction in the Coulomb blockade regime
NASA Astrophysics Data System (ADS)
Hong, X. K.; Liu, Y. S.; Feng, J. F.; Chu, J. H.
2013-10-01
Based on non-equilibrium Green's function methods, we investigate the thermal spin current through a double quantum dot (DQD) molecular junction in the Coulomb blockade regime. An external magnetic field and a temperature difference are utilized to manipulate the electron spin degree of freedom in the DQD device. When the chemical potentials are aligned with the electron-hole symmetry point, a very steady pure-spin-current thermal generator is achieved. This is because the transmission nodes of different spin channels relative to chemical potentials have a perfect mirror symmetry configuration. In addition, the pure spin current also appears near resonant regions induced by the molecular states. Particularly interesting is that the sign of the pure spin current in the electron-hole symmetry point is opposite to those appearing near resonant regions in the strong Coulomb interaction regime.
J. A. Tjon; S. J. Wallace
2006-10-27
An eikonal expansion is developed in order to provide systematic corrections to the eikonal approximation through order 1/k^2, where k is the wave number. The expansion is applied to wave functions for the Klein-Gordon equation and for the Dirac equation with a Coulomb potential. Convergence is rapid at energies above about 250 MeV. Analytical results for the eikonal wave functions are obtained for a simple analytical form of the Coulomb potential of a nucleus. They are used to investigate distorted-wave matrix elements for quasi-elastic electron scattering from a nucleus. Focusing factors are shown to arise from the corrections to the eikonal approximation. A precise form of the effective-momentum approximation is developed by use of a momentum shift that depends on the electron's energy loss.
Electron Dynamics of Interatomic Coulombic Decay in Quantum Dots: Singlet Initial State
NASA Astrophysics Data System (ADS)
Bande, Annika; Pont, Federico M.; Dolbundalchok, Praphasiri; Gokhberg, Kirill; Cederbaum, Lorenz S.
2013-03-01
In this paper we investigated the interatomic Coulombic decay (ICD) of a resonance singlet state in a model potential for two few-electron semiconductor quantum dots (QDs) by means of electron dynamics. We demonstrate that ICD is the major decay process of the resonance for the singlet wave function and compare the total and partial decay widths as a function of the QD separation with that from our previous study on the corresponding triplet states [1].
Unified derivation of exact solutions to the relativistic Coulomb problem: Lie algebraic approach
NASA Astrophysics Data System (ADS)
Panahi, H.; Baradaran, M.; Savadi, A.
2015-10-01
Exact algebraic solutions of the D-dimensional Dirac and Klein-Gordon equations for the Coulomb potential are obtained in a unified treatment. It is shown that two cases are reducible to the same basic equation, which can be solved exactly. Using the Lie algebraic approach, the general exact solutions of the problem are obtained within the framework of representation theory of the sl(2) Lie algebra.
3:00 pm Seminar field:A/lang:J Seminar Room K202, Yukawa Institute, Kyoto Dark matter in brane Oct 20 1:30 pm Seminar field:E/lang:E Seminar Room K202, Yukawa Institute, Kyoto SUSY Dark Matter 3:00 pm Seminar field:E/lang:J Seminar Room K202, Yukawa Institute, Kyoto NonPerturbative Aspects
Known-to-Unknown Approach to Teach about Coulomb's Law
ERIC Educational Resources Information Center
Thamburaj, P. K.
2007-01-01
Analogies from life experiences help students understand various relationships presented in an introductory chemistry course. Coulomb's law is a complex relationship encountered in introductory general chemistry. A proper understanding of the relationships between the quantities involved in Coulomb's law is necessary in order for students to…
Coulomb crystals in neutron star crust D. A. Baiko
crystal model. In this talk we analyze thermodynamic and elastic properties of the Coulomb crystals compensating background of electrons. In this paper we review the structure, thermodynamics, and elastic ionized and nuclear pasta phases. 2. Review of thermodynamic and elastic properties Ideal Coulomb crystal
Coulomb crystals in the magnetic field D. A. Baiko
Coulomb crystals in the magnetic field D. A. Baiko A.F. Ioffe Physical-Technical Institute The body-centered-cubic Coulomb crystal of ions in the presence of a uniform magnetic field is studied range of magnetic-field strengths and for several orientations of the field in the crystal. The phonon
Crystallization in Two-Component Coulomb Systems M. Bonitz,1
Bonitz, Michael
different type of TCP crystals [12]: crystals of bare nuclei (e.g., fully ionized carbon, oxygen, ironCrystallization in Two-Component Coulomb Systems M. Bonitz,1 V. S. Filinov,1,2 V. E. Fortov,2 P. R) The analysis of Coulomb crystallization is extended from one-component to two-component plasmas. Critical
Long-range Coulomb interaction and Majorana fermions
NASA Astrophysics Data System (ADS)
Ghazaryan, Areg; Chakraborty, Tapash
2015-09-01
We report on our exact diagonalization studies of the effects of screened and unscreened long-range Coulomb interaction on the topological superconductivity (TS) phase in a quasi-one-dimensional semiconductor wire, proximity-coupled to an s -wave superconductor. We found that inclusion of the Coulomb interaction results in an enlargement of the region of parameter values where TS can be observed. This enlargement is proportional to the screening length of the Coulomb interaction. We also found that the interaction decreases the superconducting bulk gap. Some screening of the Coulomb interaction was found to be essential for observing TS in a quasi-one-dimensional semiconductor wire proximity-coupled to an s -wave superconductor. The theoretical framework employed here is quite general and can be used to address the issue of orbital effects and multichannel two-dimensional quantum wire for observation of TS in the presence of the Coulomb interaction between electrons.
Coulomb interaction of acceptors in Cd{sub 1?x}Mn{sub x}Te/CdTe quantum dot
Kalpana, P.; Nithiananthi, P. Jayakumar, K.; Reuben, A. Merwyn Jasper D.
2014-04-24
The investigation on the effect of confining potential like isotropic harmonic oscillator type potential on the binding and the Coulomb interaction energy of the double acceptors in the presence of magnetic field in a Cd{sub 1?x}Mn{sub x}Te/CdTe Spherical Quantum Dot has been made for the Mn ion composition x=0.3 and compared with the results obtained from the square well type potential using variational procedure in the effective mass approximation.
SU(5) and SO(10) Models from F-Theory with Natural Yukawa Couplings
Tianjun Li
2010-03-03
We construct the SU(5) and SO(10) models from F-theory. Turning on the U(1) fluxes, we can break the SU(5) gauge symmetry down to the Standard Model (SM) gauge symmetry, and break the SO(10) gauge symmetry down to the SU(3)_C X SU(2)_L X SU(2)_R X U(1)_{B-L} gauge symmetry. In particular, all the SM fermion Yukawa couplings preserve the enhanced U(1)_a X U(1)_b gauge or global symmetries at the triple intersections of the SM fermion and Higgs curves. And the SM fermion masses and mixings can be generated in the presence of background fluxes. In our models, the doublet-triplet splitting problem can be solved naturally. The additional vector-like particles can obtain heavy masses via the instanton effects or Higgs mechanism and then decouple at the high scale. The SM gauge couplings at the string scale, which are splitted due to the U(1) flux effects, can be explained by considering heavy threshold corrections from the extra vector-like particles. Moreover, in the SU(5) model, we have the Yukawa coupling unification for the bottom quark and tau lepton. In the SO(10) models, we have the Yukawa coupling unification for the top and bottom quarks, and the Yukawa coupling unification for the tau lepton and tau neutrino.
Yukawa-Field Approximation of Electrostatic Free Energy and Dielectric Boundary Force
Li, Bo
Yukawa-Field Approximation of Electrostatic Free Energy and Dielectric Boundary Force Hsiao free energy of a molecular sol- vation system with an implicit or continuum solvent is constructed. The electrostatic free energy de- termines the dielectric boundary force that in turn influences crucially
Upper and lower Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model
Upper and lower Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model of the Standard Model Higgs boson based on first principle calculations, in par- ticular not relying on additional for the intended Higgs boson mass determination. These are the complex Higgs doublet as well as the top and bottom
Shear flows and shear viscosity in a two-dimensional Yukawa system (dusty plasma)
Goree, John
Shear flows and shear viscosity in a two-dimensional Yukawa system (dusty plasma) V. Nosenko and J) Abstract The shear viscosity of a two-dimensional liquid-state dusty plasma was mea- sured experimentally in the shear flow to a Navier-Stokes model, the kinematic viscosity was calculated; it was of order 1 mm2s-1
Shear Viscosity and Shear Thinning in Two-Dimensional Yukawa Liquids Z. Donko,1
Goree, John
Shear Viscosity and Shear Thinning in Two-Dimensional Yukawa Liquids Z. Donko´,1 J. Goree,2 P nonequilibrium molecular dynamics simulation methods. Shear viscosity values in the limit of small shear rates it is demonstrated that this liquid exhibits shear thinning; i.e., the viscosity diminishes with increasing shear
Shear viscosity and shear thinning in two-dimensional Yukawa , J. Goree2
Goree, John
Shear viscosity and shear thinning in two-dimensional Yukawa liquids Z. Donk´o1 , J. Goree2 , P using two different nonequi- librium molecular dynamics simulation methods. Shear viscosity values.e., the viscosity diminishes with increasing shear rate. It is expected that two-dimensional dusty plasmas
Study on Coulomb explosions of ion mixtures
Boella, E; D'Angola, A; Coppa, G; Silva, L O
2015-01-01
The paper presents a theoretical work on the dynamics of Coulomb explosion for spherical nanoplasmas composed by two different ion species. Particular attention has been dedicated to study the energy spectra of the ions with the larger charge-to-mass ratio. The connection between the formation of shock shells and the energy spread of the ions has been the object of a detailed analysis, showing that under particular conditions the width of the asymptotic energy spectrum tends to become very narrow, which leads to a multi-valued ion phase-space. The conditions to generate a quasi mono-energetic ion spectrum have been rigorously demonstrated and verifed by numerical simulations, using a technique that, exploiting the spherical symmetry of the problem, allows one to obtain very accurate and precise results.
The ghost propagator in Coulomb gauge
NASA Astrophysics Data System (ADS)
Watson, P.; Reinhardt, H.
2011-05-01
We present results for a numerical study of the ghost propagator in Coulomb gauge whereby lattice results for the spatial gluon propagator are used as input to solving the ghost Dyson-Schwinger equation. We show that in order to solve completely, the ghost equation must be supplemented by a boundary condition (the value of the inverse ghost propagator dressing function at zero momentum) which determines if the solution is critical (zero value for the boundary condition) or subcritical (finite value). The various solutions exhibit a characteristic behavior where all curves follow the same (critical) solution when going from high to low momenta until `forced' to freeze out in the infrared to the value of the boundary condition. The boundary condition can be interpreted in terms of the Gribov gauge-fixing ambiguity; we also demonstrate that this is not connected to the renormalization. Further, the connection to the temporal gluon propagator and the infrared slavery picture of confinement is discussed.
Tabletop nucleosynthesis driven by cluster Coulomb explosion.
Last, Isidore; Jortner, Joshua
2006-10-27
Coulomb explosion of completely ionized (CH4)n, (NH3)n, and (H2O)n clusters will drive tabletop nuclear reactions of protons with 12C6+, 14N7+, and 16O8+ nuclei, extending the realm of nuclear reactions driven by ultraintense laser-heterocluster interaction. The realization for nucleosynthesis in exploding cluster beams requires complete electron stripping from the clusters (at laser intensities I(M) > or = 10(19) W cm(-2)), the utilization of nanodroplets of radius 300-700 A for vertical ionization, and the attainment of the highest energies for the nuclei (i.e., approximately 30 MeV for heavy nuclei and approximately 3 MeV for protons). PMID:17155473
The ghost propagator in Coulomb gauge
Watson, P.; Reinhardt, H.
2011-05-23
We present results for a numerical study of the ghost propagator in Coulomb gauge whereby lattice results for the spatial gluon propagator are used as input to solving the ghost Dyson-Schwinger equation. We show that in order to solve completely, the ghost equation must be supplemented by a boundary condition (the value of the inverse ghost propagator dressing function at zero momentum) which determines if the solution is critical (zero value for the boundary condition) or subcritical (finite value). The various solutions exhibit a characteristic behavior where all curves follow the same (critical) solution when going from high to low momenta until 'forced' to freeze out in the infrared to the value of the boundary condition. The boundary condition can be interpreted in terms of the Gribov gauge-fixing ambiguity; we also demonstrate that this is not connected to the renormalization. Further, the connection to the temporal gluon propagator and the infrared slavery picture of confinement is discussed.
M. Beneke; Y. Kiyo; K. Schuller
2007-05-30
We obtain analytic expressions for the third-order corrections due to the strong interaction Coulomb potential to the S-wave Green function, energy levels and wave functions at the origin for arbitrary principal quantum number n. Together with the known non-Coulomb correction this results in the complete spectrum of S-states up to order alpha_s^5. The numerical impact of these corrections on the Upsilon spectrum and the top quark pair production cross section near threshold is estimated.
Exact SU(5) Yukawa matrix unification in the general flavour violating MSSM
NASA Astrophysics Data System (ADS)
Iskrzy?ski, Mateusz; Kowalska, Kamila
2015-04-01
We investigate the possibility of satisfying the SU(5) boundary condition Y d = Y eT at the GUT scale within the renormalizable R-parity conserving Minimal Supersymmetric Standard Model (MSSM). Working in the super-CKM basis, we consider non-zero flavour off-diagonal entries in the soft SUSY-breaking mass matrices and the A-terms. At the same time, the diagonal A-terms are assumed to be suppressed by the respective Yukawa couplings. We show that a non-trivial flavour structure of the soft SUSY-breaking sector can contribute to achieving precise Yukawa coupling unification for all three families, and that the relevant flavour-violating parameters are , , and A {12/21/ d }. We indicate the parameter space regions where the Yukawa unification condition can be satisfied, and we demonstrate that it is consistent with a wide set of experimental constraints, including flavour and electroweak observables, Higgs physics and the LHC bounds. However, as a consequence of the down-electron Yukawa unification requirement, the MSSM vacuum in our scenario is metastable, though long-lived. We also point out that the lightest neutralino needs to be almost purely bino-like and relatively light, with the mass in the ballpark of 250 GeV. Since the proper value of the dark matter relic density is in this case obtained through co-annihilation with a sneutrino, at least one generation of sleptons must be light. Such a clear experimental prediction makes the flavour-violating SU(5) Yukawa unification scenario fully testable at the LHC TeV with the 3-lepton searches for electroweakino production.
The effects of Coulomb interactions on the superconducting gaps in iron-based superconductors
NASA Astrophysics Data System (ADS)
Leong, Zhidong; Phillips, Philip
2015-03-01
Recent ARPES measurements on Co-doped LiFeAs report a large and robust superconducting gap on a band below the chemical potential. We will show that, unlike a conventional BCS theory, a multiband system with strong interband Coulomb interactions can explain the observations. We use a two-band model consisting of a superconducting electron band and a hole band that is below the chemical potential. The two bands are coupled via interband Coulomb interactions. Using Eliashberg theory, we found that superconductivity in the electron band induces a large superconducting gap in the hole band. Furthermore, the repulsive nature of the Coulomb interactions gives the induced gap an opposite sign, corresponding to an s+/- gap symmetry. Unlike other families of iron pnictides, the gap symmetry of LiFeAs has not been ascertained experimentally. The implications for the superconducting mechanism in iron pnictides will be discussed. Z. Leong is supported by a scholarship from the Agency of Science, Technology and Research. P. Phillips is supported by the Center for Emergent Superconductivity, a DOE Energy Frontier Research Center, Grant No. DE-AC0298CH1088.
Localizing gauge fields on a topological Abelian string and the Coulomb law
Torrealba S, Rafael S.
2010-07-15
The confinement of electromagnetic field is studied in axial symmetrical, warped, six-dimensional brane world, using a recently proposed topological Abelian string-vortex solution as background. It was found, that the massless gauge field fluctuations follow four-dimensional Maxwell equations in the Lorenz gauge. The massless zero mode is localized when the thickness of the string vortex is less than 5{beta}/4{pi}e{sup 2}v{sup 2} and there are no other localized massless modes. There is also an infinite of nonlocalized massive Fourier modes, that follow four-dimensional Proca equations with a continuous spectrum. To compute the corrections to the Coulomb potential, a radial cutoff was introduced, in order to achieve a discrete mass spectrum. As a main result, a (R{sub o}/{beta}R{sup 2}) correction was found for the four-dimensional effective Coulomb law; the result is in correspondence with the observed behavior of the Coulomb potential at today's measurable distances.
Hexatic and mesoscopic phases in a 2D quantum coulomb system.
Clark, Bryan K; Casula, Michele; Ceperley, D M
2009-07-31
We study the Wigner crystal melting in a two-dimensional quantum system of distinguishable particles interacting via the 1/r Coulomb potential. We use quantum Monte Carlo methods to calculate its phase diagram, locate the Wigner crystal region, and analyze its instabilities towards the liquid phase. We discuss the role of quantum effects in the critical behavior of the system, and compare our numerical results with the classical theory of melting, and the microemulsion theory of frustrated Coulomb systems. We find a Pomeranchuk effect much larger then in solid helium. In addition, we find that the exponent for the algebraic decay of the hexatic phase differs significantly from the Kosterilitz-Thouless theory of melting. We search for the existence of mesoscopic phases and find evidence of metastable bubbles but no mesoscopic phase that is stable in equilibrium. PMID:19792514
Strong Laser Field Fragmentation of H{sub 2}: Coulomb Explosion without Double Ionization
Manschwetus, B.; Nubbemeyer, T.; Gorling, K.; Steinmeyer, G.; Rottke, H.; Eichmann, U.; Sandner, W.
2009-03-20
We observe fragmentation of H{sub 2} molecules exposed to strong laser fields into excited neutral atoms. The measured excited neutral fragment spectrum resembles the ionic fragmentation spectrum including peaks due to bond softening and Coulomb explosion. To explain the occurrence of excited neutral fragments and their high kinetic energy, we argue that the recently investigated phenomenon of frustrated tunnel ionization is also at work in the neutralization of H{sup +} ions into excited H* atoms. In this process the tunneled electron does not gain enough drift energy from the laser field to escape the Coulomb potential and is recaptured. Calculation of classical trajectories as well as a correlated detection measurement of neutral excited H* and H{sup +} ions support the mechanism.
Ji-sheng Chen
2007-01-23
A hidden local symmetry formalism with a two-photon counterterm approach is performed based on the relativistic continuum quantum many-body theory. The underlying electromagnetic under-screening as well as screening effects between the electric charged point-like electrons and composite protons are discussed by analyzing the in-medium isospin mixing of Lorentz vector with scalar due to electromagnetic photon. Besides the usual screening results, the main conclusion is that an effective oscillatory instantaneous Coulomb potential between the like-charged collective electrons contributes a very large negative term to the equation of state. This counterintuitive like-charged attraction results from the modulation factor of the opposite charged baryon superfluid background. The anomalous long distance quantum dragging effects between the collective electrons can be induced in a compact Coulomb confinement environment. The physics is of the strongly coupling characteristic in a specific dilute regime.
Scattering and stopping of swift diatomic molecules under Coulomb explosion
Sigmund, P. . Dept. of Physics Argonne National Lab., IL )
1991-01-01
The scattering and stopping of the fragments of a fast diatomic molecule under Coulomb explosion has been analyzed theoretically. The central assumption in the scheme is the dominance of Coulomb explosion, while electronic stopping (including wake forces) and elastic scattering are treated as perturbations. Charge exchange has been neglected. Coulomb images of penetration phenomena are heavily distorted. For small penetrated layer thicknesses, images appear contracted in the direction of the molecular axis, and expanded perpendicular to it. This distortion is described quantitatively by a linear transformation. General expressions have been derived for the effect of continuous and stochastic forces on the distribution of fragment velocities from Coulomb explosion (the ring pattern''). Moreover, relations have been found that allow to scale velocity distributions valid in the absence of Coulomb explosion into distributions allowing for Coulomb explosion. Applications concern the shift in ring pattern due to electronic stopping, the lateral broadening due to multiple scattering and the effect of zero-point motion on the Coulomb image of a molecule. 14 refs., 5 figs.
Characterizing intra-exciton Coulomb scattering in terahertz excitations
Zybell, S.; Eßer, F.; Helm, M.; Bhattacharyya, J.; Winnerl, S.; Schneider, H.; Schneebeli, L.; Böttge, C. N.; Kira, M.; Koch, S. W.; Andrews, A. M.; Strasser, G.
2014-11-17
An intense terahertz field is applied to excite semiconductor quantum wells yielding strong non-equilibrium exciton distributions. Even though the relaxation channels involve a complicated quantum kinetics of Coulomb and phonon effects, distinct relaxation signatures of Coulomb scattering are identified within time-resolved photoluminescence by comparing the experiment with a reduced model that contains all relevant microscopic processes. The analysis uncovers a unique time scale for the Coulomb scattering directly from experiments and reveals the influence of phonon relaxation as well as radiative decay.
Investigation of deformed nuclei with a new potential combination
NASA Astrophysics Data System (ADS)
Javadimanesh, E.; Hassanabadi, H.; A. Rajabi, A.; Rahimov, H.; Zarrinkamar, S.
2013-11-01
We investigate the alpha-decay half-lives of non-spherical nuclei with the Yukawa potential as the proximity potential and an angle-dependent term that accounts for the deformation effects and apply the results to Ho, Tb, Lu, Tm, Ta, Hf, Yb, Re, Ir, Pt, Au, Po, etc. as examples. The comparison with the existing data is encouraging.
Parametrization of the Paris N-N potential
Lacombe, M.; Loiseau, B.; Richard, J.M.; Vinh Mau, R.; Cote, J.; Pires, P.; de Tourreil, R.
1980-03-01
In view of practical nuclear structure calculations the Paris N-N potential is parametrized in a simple analytical form. This parametrization consists of a regularized discrete superposition of Yukawa-type terms. Results for phase shifts and deuteron parameters are presented as well as nuclear matter binding energy obtained with this potential.
The equation-transform model for Dirac–Morse problem including Coulomb tensor interaction
Ortakaya, Sami
2013-11-15
The approximate solutions of Dirac equation with Morse potential in the presence of Coulomb-like tensor potential are obtained by using Laplace transform (LT) approach. The energy eigenvalue equation of the Dirac particles is found and some numerical results are obtained. By using convolution integral, the corresponding radial wave functions are presented in terms of confluent hypergeometric functions. -- Highlights: •The Dirac equation with tensor interaction is solved by using Laplace transform. •For solving this equation, we introduce the equation-transform model. •Numerical results and plots for pseudospin and spin symmetric solutions are given. •The obtained numerical results by using transform method are compared with orthogonal polynomial method.
Analysis of {alpha}-induced reactions on {sup 151}Eu below the Coulomb barrier
Avrigeanu, V.; Avrigeanu, M.
2011-01-15
Novel measurements of ({alpha},{gamma}) and ({alpha},n) reaction cross sections on the target nucleus {sup 151}Eu, close to the reaction thresholds, support the choice of recently proposed parameters of the {alpha}-particle optical model potential below the Coulomb barrier. A better understanding of the {alpha}-particle optical potential at these energies leads to a statistical model analysis of additional partial cross sections that were measured but not considered within a former model analysis. On this basis we have tentatively assigned a modified J{sup {pi}}=9{sup -} spin and parity to the 22.7-h isomer in {sup 154}Tb.
NASA Astrophysics Data System (ADS)
Hollik, Wolfgang Gregor
2016-01-01
Testing the stability of the electroweak vacuum in any extension of the Standard Model Higgs sector is of great importance to verify the consistency of the theory. Multi-scalar extensions as the Minimal Supersymmetric Standard Model generically lead to unstable configurations in certain regions of parameter space. An exact minimization of the scalar potential is rather an impossible analytic task. To give handy analytic constraints, a specific direction in field space has to be considered which is a simplification that tends to miss excluded regions, however good to quickly check parameter points. We describe a yet undescribed class of charge and color breaking minima as they appear in the Minimal Supersymmetric Standard Model, exemplarily for the case of non-vanishing bottom squark vacuum expectation values constraining the combination ?Yb in a non-trivial way. Contrary to famous A-parameter bounds, we relate the bottom Yukawa coupling with the supersymmetry breaking masses. Another bound can be found relating soft breaking masses and ? only. The exclusions follow from the tree-level minimization and can change dramatically using the one-loop potential. Estimates of the lifetime of unstable configurations show that they are either extremely short- or long-lived.
Accelerated Monte Carlo Methods for Coulomb Collisions
NASA Astrophysics Data System (ADS)
Rosin, Mark; Ricketson, Lee; Dimits, Andris; Caflisch, Russel; Cohen, Bruce
2014-03-01
We present a new highly efficient multi-level Monte Carlo (MLMC) simulation algorithm for Coulomb collisions in a plasma. The scheme, initially developed and used successfully for applications in financial mathematics, is applied here to kinetic plasmas for the first time. The method is based on a Langevin treatment of the Landau-Fokker-Planck equation and has a rich history derived from the works of Einstein and Chandrasekhar. The MLMC scheme successfully reduces the computational cost of achieving an RMS error ? in the numerical solution to collisional plasma problems from ?(?-3) - for the standard state-of-the-art Langevin and binary collision algorithms - to a theoretically optimal ?(?-2) scaling, when used in conjunction with an underlying Milstein discretization to the Langevin equation. In the test case presented here, the method accelerates simulations by factors of up to 100. We summarize the scheme, present some tricks for improving its efficiency yet further, and discuss the method's range of applicability. Work performed for US DOE by LLNL under contract DE-AC52- 07NA27344 and by UCLA under grant DE-FG02-05ER25710.
Coulomb gauge ghost Dyson-Schwinger equation
NASA Astrophysics Data System (ADS)
Watson, P.; Reinhardt, H.
2010-12-01
A numerical study of the ghost Dyson-Schwinger equation in Coulomb gauge is performed and solutions for the ghost propagator found. As input, lattice results for the spatial gluon propagator are used. It is shown that in order to solve completely, the equation must be supplemented by a nonperturbative boundary condition (the value of the inverse ghost propagator dressing function at zero momentum), which determines if the solution is critical (zero value for the boundary condition) or subcritical (finite value). The various solutions exhibit a characteristic behavior where all curves follow the same (critical) solution when going from high to low momenta until forced to freeze out in the infrared to the value of the boundary condition. The renormalization is shown to be largely independent of the boundary condition. The boundary condition and the pattern of the solutions can be interpreted in terms of the Gribov gauge-fixing ambiguity. The connection to the temporal gluon propagator and the infrared slavery picture of confinement is explored.
Coulomb Collision Algorithms for Particle Codes
NASA Astrophysics Data System (ADS)
Cohen, Bruce
2006-04-01
This paper surveys some of the particle code algorithms used to model Coulomb collisions in fully ionized plasmas, e.g., pair-wise operators such as the Takizuka-Abe^1 scheme and extensions^2, Langevin equation collision operators^3,4, and partially linearized gyrokinetic collisions operators for strongly magnetized plasmas.^5,6,7 Some recent experience is reported.^8 Issues such as physics completeness, accuracy, and comparative algorithm performance are highlighted. 1. T. Takizuka and H. Abe, J. Comput. Phys. 25, 205 (1977). 2. K. Nanbu, Phys. Rev. E 55, 4642 (1997). 3. M.E. Jones, et al., J. Comp. Phys. 123, 169 (1996). 4. W.M. Manheimer, M. Lampe, and G. Joyce, et al., J. Comp. Phys. 138, 565 (1997). 5. X.Q. Xu and M.N. Rosenbluth, Phys. Fluids B 3, 627 (1991). 6. A.M. Dimits and B.I. Cohen, Phys. Rev. E 49, 709 (1994). 7. Z. Lin, W. M. Tang, and W. W. Lee, Phys.Plasmas 2, 2975 (August 1995). 8. B.I. Cohen, et al., ``Effects of ion-ion collisions and inhomogeneity in two-dimensional kinetic ion simulations of stimulated Brillouin backscattering,'' accepted for publication in Phys. Plasmas (2006).
Le probleme quantique bicomplexe du potentiel de Coulomb
NASA Astrophysics Data System (ADS)
Mathieu, Jeremie
In this master's thesis, is gathered a great part of my work on bicomplex quantum mechanics. Bicomplex numbers are the second order multicomplex generalization of complex numbers. Equipped with the standard addition and multiplication, they form an algebraic structure called a commutative ring with unity and are one of many known generalizations of the real number system. It has been almost eighty years since it's been proposed to use an algebra of a superior dimension than the one of complex numbers to construct the mathematical formalism of quantum mechanics. However it's only been since less than a decade ago that the idea of using the bicomplex numbers to do so has been seriously considered. In that sense, the complete resolution of the quantum harmonic oscillator in a bicomplex Hilbert space was the first major achievement of this ambitious project. This thesis, by article style, is a continuation of this work of generalization. It presents, by an axiomatic approach, the complete differential solution of the bicomplex quantum Coulomb potential problem and half of its algebraic solution.
Interatomic Coulombic decay in two coupled quantum wells
NASA Astrophysics Data System (ADS)
Goldzak, Tamar; Gantz, Liron; Gilary, Ido; Bahir, Gad; Moiseyev, Nimrod
2015-04-01
Interatomic Coulombic decay (ICD) is a relaxation process induced by electronic correlation. In this work we study the ICD process in a two coupled quantum wells (QWs) nanostructure. We study a simple one-dimensional effective potential using experimental parameters of the semiconductor QW layers, i.e., using the single-band effective-mass approximation. In our calculations we consider the discontinuity of the effective mass of the electron in each of the QW layers. We control the ICD lifetime by changing the distance between the two wells. The expected overall trend is a decrease of ICD lifetime with a decrease in the distance between the wells. We show that the distance can be tuned such that the emitted ICD electron is trapped in a metastable state in the con-tinuum, i.e., a one-electron resonance state. This causes the lifetime of the ICD to be an order of magnitude smaller even at very long distances, and improves the efficiency of the ICD process. For the ICD to be the dominant decay mechanism it must prevail over all other possible competitive decay processes. We have found that the lifetime of the ICD is on the time scale of picoseconds. Therefore, based on our results we can design an experiment that will observe the ICD phenomenon in QWs nanostructure. This work can lead to a design of a wavelength-sensitive detector which is efficient even at low intensities.
Indirect Coulomb energy for two-dimensional atoms
Benguria, Rafael D.; Tusek, Matej
2012-09-15
In this paper we provide a family of lower bounds on the indirect Coulomb energy for atomic and molecular systems in two dimensions in terms of a functional of the single particle density with gradient correction terms.
NASA Astrophysics Data System (ADS)
Heinen, Marco; Holmqvist, Peter; Banchio, Adolfo J.; Nägele, Gerhard
2011-01-01
We present a comprehensive study of the equilibrium pair structure in fluids of nonoverlapping spheres interacting by a repulsive Yukawa-like pair potential, with special focus on suspensions of charged colloidal particles. The accuracy of several integral equation schemes for the static structure factor, S(q), and radial distribution function, g(r), is investigated in comparison to computer simulation results and static light scattering data on charge-stabilized silica spheres. In particular, we show that an improved version of the so-called penetrating-background corrected rescaled mean spherical approximation (PB-RMSA) by Snook and Hayter [Langmuir 8, 2880 (1992)], referred to as the modified PB-RMSA (MPB-RMSA), gives pair structure functions which are in general in very good agreement with Monte Carlo simulations and results from the accurate but nonanalytical and therefore computationally more expensive Rogers-Young integral equation scheme. The MPB-RMSA preserves the analytic simplicity of the standard rescaled mean spherical (RMSA) solution. The combination of high accuracy and fast evaluation makes the MPB-RMSA ideally suited for extensive parameter scans and experimental data evaluation, and for providing the static input to dynamic theories. We discuss the results of extensive parameter scans probing the concentration scaling of the pair structure of strongly correlated Yukawa particles, and we determine the liquid-solid coexistence line using the Hansen-Verlet freezing rule.
Diffusion and Coulomb separation of ions in dense matter.
Beznogov, M V; Yakovlev, D G
2013-10-18
We analyze diffusion equations in strongly coupled Coulomb mixtures of ions in dense stellar matter. Strong coupling of ions in the presence of gravitational forces and electric fields (induced by plasma polarization in the presence of gravity) produces a specific diffusion current which can separate ions with the same A/Z (mass to charge number) ratios but different Z. This Coulomb separation of ions can be important for the evolution of white dwarfs and neutron stars. PMID:24182248
A New Hybrid STEP/Coulomb model for Aftershock Forecasting
NASA Astrophysics Data System (ADS)
Steacy, S.; Jimenez, A.; Gerstenberger, M.
2014-12-01
Aftershock forecasting models tend to fall into two classes - purely statistical approaches based on clustering, b-value, and the Omori-Utsu law; and Coulomb rate-state models which relate the forecast increase in rate to the magnitude of the Coulomb stress change. Recently, hybrid models combining physical and statistical forecasts have begun to be developed, for example by Bach and Hainzl (2012) and Steacy et al. (2013). The latter approach combined Coulomb stress patterns with the STEP (short-term earthquake probability) model by redistributing expected rate from areas with decreased stress to regions where the stress had increased. The chosen 'Coulomb Redistribution Parameter' (CRP) was 0.93, based on California earthquakes, which meant that 93% of the total rate was expected to occur where the stress had increased. The model was tested against the Canterbury sequence and the main result was that the new model performed at least as well as, and often better than, STEP when tested against retrospective data but that STEP was generally better in pseudo-prospective tests that involved data actually available within the first 10 days of each event of interest. The authors suggested that the major reason for this discrepancy was uncertainty in the slip models and, particularly, in the geometries of the faults involved in each complex major event. Here we develop a variant of the STEP/Coulomb model in which the CRP varies based on the percentage of aftershocks that occur in the positively stressed areas during the forecast learning period. We find that this variant significantly outperforms both STEP and the previous hybrid model in almost all cases, even when the input Coulomb model is quite poor. Our results suggest that this approach might be more useful than Coulomb rate-state when the underlying slip model is not well constrained due to the dependence of that method on the magnitude of the Coulomb stress change.
Random Coulomb antiferromagnets: From diluted spin liquids to Euclidean random matrices
NASA Astrophysics Data System (ADS)
Rehn, J.; Sen, Arnab; Andreanov, A.; Damle, Kedar; Moessner, R.; Scardicchio, A.
2015-08-01
We study a disordered classical Heisenberg magnet with uniformly antiferromagnetic interactions which are frustrated on account of their long-range Coulomb form, i.e., J (r )˜-A lnr in d =2 and J (r )˜A /r in d =3 . This arises naturally as the T ?0 limit of the emergent interactions between vacancy-induced degrees of freedom in a class of diluted Coulomb spin liquids (including the classical Heisenberg antiferromagnets in checkerboard, SCGO, and pyrochlore lattices) and presents a novel variant of a disordered long-range spin Hamiltonian. Using detailed analytical and numerical studies we establish that this model exhibits a very broad paramagnetic regime that extends to very large values of A in both d =2 and d =3 . In d =2 , using the lattice-Green-function-based finite-size regularization of the Coulomb potential (which corresponds naturally to the underlying low-temperature limit of the emergent interactions between orphans), we find evidence that freezing into a glassy state occurs only in the limit of strong coupling, A =? , while no such transition seems to exist in d =3 . We also demonstrate the presence and importance of screening for such a magnet. We analyze the spectrum of the Euclidean random matrices describing a Gaussian version of this problem and identify a corresponding quantum mechanical scattering problem.
Ismail, M.; Seif, W. M.
2010-03-15
A simple straightforward method has been presented to predict the dependence of barrier distributions at arbitrary orientations on different deformations. The proposed interpretation is developed independently of the complicated numerical calculations. It is related to the change of half-density radius of the deformed nucleus, in the direction of the separation vector. The microscopic calculations of Coulomb barrier are carried out by using a realistic density dependent nucleon-nucleon (NN) interaction, BDM3Y, for the interaction between spherical, {sup 48}Ca, and deformed, {sup 244}Pu, nuclei, as an example. To do so, the double-folding model for the interaction of spherical-deformed nuclei is put in a suitable computational form for the calculation of the potential at several separation distances and orientation angles using the density dependent NN force without consuming computational time. We found that the orientation distributions of the Coulomb barrier parameters show similar patterns to those of the interacting deformed nucleus radius. It is found that the orientation distribution of the Coulomb barrier radius follows the same variation of the deformed nucleus radius while the barrier height distribution follows it inversely. This correlation (anticorrelation) allows a simple evaluation of the orientation barrier distribution which would be very helpful to estimate when the barrier parameters will increase or decrease and at which orientations they will be independent of the deformation. This also allows us to estimate the compact and elongated configurations of the interacting nuclei which lead to hot and cold fusion, respectively.
Konuma, Michiji; Gotoh, Haruyoshi; Hayakawa, Hisao; Hirata, Kohji; Ito, Kazuyuki; Ito, Kenji; Kanaya, Kazuyuki; Konagaya, Daisuke; Kugo, Taichiro; Namba, Chusei; Nishitani, Tadashi; Takaiwa, Yoshinobu; Tanabashi, Masaharu; Tanaka, Kio; Tanaka, Sho; Ukegawa, Fumihiko; Yoshikawa, Tadashi
2013-01-01
Hideki Yukawa, Sin-itiro Tomonaga and Shoichi Sakata pioneered nuclear and particle physics and left enduring legacies. Their friendly collaboration and severe competition laid the foundation to bring up the active postwar generation of nuclear and particle physicists in Japan. In this presentation we illustrate milestones of nuclear and particle physics in Japan from 1930's to mid-1940's which have been clarified in Yukawa Hall Archival Library, Tomonaga Memorial Room and Sakata Memorial Archival Library.
NASA Astrophysics Data System (ADS)
Konuma, Michiji; Bando, Masako; Gotoh, Haruyoshi; Hayakawa, Hisao; Hirata, Kohji; Ito, Kazuyuki; Ito, Kenji; Kanaya, Kazuyuki; Konagaya, Daisuke; Kugo, Taichiro; Namba, Chusei; Nishitani, Tadashi; Takaiwa, Yoshinobu; Tanabashi, Masaharu; Tanaka, Kio; Tanaka, Sho; Ukegawa, Fumihiko; Yoshikawa, Tadashi
Hideki Yukawa, Sin-itiro Tomonaga and Shoichi Sakata pioneered nuclear and particle physics and left enduring legacies. Their friendly collaboration and severe competition laid the foundation to bring up the active postwar generation of nuclear and particle physicists in Japan. In this presentation we illustrate milestones of nuclear and particle physics in Japan from 1930's to mid-1940's which have been clarified in Yukawa Hall Archival Library, Tomonaga Memorial Room and Sakata Memorial Archival Library.
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
Philipp Gerhold; Karl Jansen; Jim Kallarackal
2012-03-20
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling.
Remarkable coincidence for the top Yukawa coupling and an approximately massless bound state
Froggatt, C. D.; Nielsen, H. B.
2009-08-01
We calculate, with several corrections, the nonrelativistic binding by Higgs exchange and gluon exchange between six top and six antitop quarks (actually replaced by left-handed b quarks from time to time). The remarkable result is that, within our calculational accuracy of the order of 14% in the top-quark Yukawa coupling g{sub t}, the experimental running top-quark Yukawa coupling g{sub t}=0.935 happens to have just that value which gives a perfect cancellation of the unbound mass=12 top-quark masses by this binding energy. In other words the bound state is massless to the accuracy of our calculation. Our calculation is in disagreement with a similar calculation by Kuchiev et al., but this deviation may be explained by a phase transition. We and Kuchiev et al. compute on different sides of this phase transition.
Seesaw mechanism with four texture zeros in the neutrino Yukawa matrix
Jiajun Liao; D. Marfatia; K. Whisnant
2013-04-16
With the recent observation of nonzero \\theta_{13}, five neutrino oscillation parameters are now known. By imposing four zeros in the Yukawa coupling matrix of the type I seesaw model, the number of parameters in the neutrino mass matrix is reduced to seven, and we are able to make predictions for the lightest neutrino mass, Dirac CP phase, and neutrinoless double beta decay. Four texture zeros in the Yukawa coupling matrix is equivalent to either a single texture zero or a single cofactor zero for an off-diagonal element of the light neutrino mass matrix. We find strong similarities between single texture zero models with one mass ordering and single cofactor zero models with the opposite mass ordering. In the context of a specific class of single-flavor leptogenesis models, we find additional constraints on the parameter space.
Yukawa effects on the clock onboard a drag-free satellite
Xue-Mei Deng; Yi Xie
2013-03-05
The Yukawa correction to the Newtonian gravitational force is accepted as a parameterization of deviations from the inverse-square law of gravity which might be caused by new physics beyond the standard model of particles and the general theory of relativity. We investigate these effects on the clock onboard a drag-free satellite: dynamics of the satellite and influence on the time transfer link. We find the Yukawa signal in the time transfer is much harder to detect with current state of clocks than those effects on the dynamics, especially the secular change of periastron, by laser ranging in the case of an artificial Earth satellite carrying a frequency standard with an orbit of $a=10^7$\\,m and $e=0.01$.
Thermodynamics of Yukawa fluids near the one-component-plasma limit
Sergey A. Khrapak; Igor L. Semenov; Lenaic Couedel; Hubertus M. Thomas
2015-07-02
Thermodynamics of weakly screened (near the one-component-plasma limit) Yukawa fluids in two and three dimensions is analyzed in detail. It is shown that the thermal component of the excess internal energy of these fluids, when expressed in terms of the properly normalized coupling strength, exhibits the scaling pertinent to the corresponding one-component-plasma limit (the scalings differ considerably between the two- and three-dimensional situations). This provides us with a simple and accurate practical tool to estimate thermodynamic properties of weakly screened Yukawa fluids. Particular attention is paid to the two-dimensional fluids, for which several important thermodynamic quantities are calculated to illustrate the application of the approach.
Yukawa couplings in string theory: the case for F-theory GUT's
NASA Astrophysics Data System (ADS)
Font, Anamaría
2015-11-01
We study the pattern of Yukawa couplings in local F-theory SU(5) GUT's. Couplings for the third family of quarks and leptons appear at the perturbative level, but to reproduce the observed couplings for the lighter families requires non-perturbative dynamics. We show that corrections due to instanton effects do lead to a Yukawa matrix with a hierarchical structure. Our results apply to both down-like and up- like 10 × 10 × 5 couplings. The models include magnetic fluxes needed for a chiral spectrum and for symmetry breaking down to the Standard Model. We compute the holomorphic couplings via residues and then obtain the physical couplings taking into account the normalization of wavefunction profiles. Combining non-perturbative corrections and magnetic fluxes allows to fit the measured masses and hierarchies of the third and second generations in the Standard Model.
Two-loop electroweak threshold corrections to the bottom and top Yukawa couplings
NASA Astrophysics Data System (ADS)
Kniehl, Bernd A.; Veretin, Oleg L.
2014-08-01
We study the relationship between the MSbar Yukawa coupling and the pole mass for the bottom and top quarks at the two-loop electroweak order O(?2) in the gaugeless limit of the standard model. We also consider the MSbar to pole mass relationships at this order, which include tadpole contributions to ensure the gauge independence of the MSbar masses. In order to suppress numerically large tadpole contributions, we propose a redefinition of the running heavy-quark mass in terms of the MSbar Yukawa coupling. We also present ?r in the MSbar scheme at O(?2) in the gaugeless limit. As an aside, we also list the exact two-loop expression for the mass counterterms of the bottom and top quarks.
Two-loop electroweak threshold corrections to the bottom and top Yukawa couplings
Bernd A. Kniehl; Oleg L. Veretin
2015-05-05
We study the relationship between the $\\overline{\\mathrm{MS}}$ Yukawa coupling and the pole mass for the bottom and top quarks at the two-loop electroweak order ${\\cal O}(\\alpha^2)$ in the gaugeless limit of the standard model. We also consider the $\\overline{\\mathrm{MS}}$ to pole mass relationships at this order, which include tadpole contributions to ensure the gauge independence of the $\\overline{\\mathrm{MS}}$ masses. In order to suppress numerically large tadpole contributions, we propose a redefinition of the running heavy-quark mass in terms of the $\\overline{\\mathrm{MS}}$ Yukawa coupling. We also present $\\Delta r$ in the $\\overline{\\mathrm{MS}}$ scheme at ${\\cal O}(\\alpha^2)$ in the gaugeless limit. As an aside, we also list the exact two-loop expression for the mass counterterms of the bottom and top quarks.
On the estimation of sound speed in two-dimensional Yukawa fluids
NASA Astrophysics Data System (ADS)
Semenov, I. L.; Khrapak, S. A.; Thomas, H. M.
2015-11-01
The longitudinal sound speed in two-dimensional Yukawa fluids is estimated using the conventional hydrodynamic expression supplemented by appropriate thermodynamic functions proposed recently by Khrapak et al. [Phys. Plasmas 22, 083706 (2015)]. In contrast to the existing approaches, such as quasi-localized charge approximation (QLCA) and molecular dynamics simulations, our model provides a relatively simple estimate for the sound speed over a wide range of parameters of interest. At strong coupling, our results are shown to be in good agreement with the results obtained using the QLCA approach and those derived from the phonon spectrum for the triangular lattice. On the other hand, our model is also expected to remain accurate at moderate values of the coupling strength. In addition, the obtained results are used to discuss the influence of the strong coupling effects on the adiabatic index of two-dimensional Yukawa fluids.
The Quest for Pionic and Kaonic Nuclear Bound Systems Following Yukawa and Tomonaga
Toshimitsu Yamazaki
2007-09-09
After sketching some historical events related to Yukawa and Tomonaga concerning the birth of mesons, the author describes recent developments in the spectroscopy of pion-nucleus bound states via "pion-transfer" reactions. The role of pions as Nambu-Goldstone bosons in nuclear media is emphasized by recently obtained experimental evidence for the partial restoration of chiral symmetry breaking. New light is shed on Kbar mesons, which play a unique role in forming dense nuclear systems. The basic unit, K- pp, is predicted to possess a molecular structure with quasi-Lambda(1405) as an "atomic constituent". We find here "super strong nuclear force" produced by a migrating real Kbar meson in the Heitler-London-Heisenberg scheme in place of the normal nuclear force mediated by Yukawa's virtual mesons.
Popescu, Florentin; Sen, Cengiz; Dagotto, Elbio R; Moreo, Adriana
2007-01-01
The crossover between an impurity band (IB) and a valence band (VB) regime as a function of the magnetic impurity concentration in a model for diluted magnetic semiconductors (DMSs) is studied systematically by taking into consideration the Coulomb attraction between the carriers and the magnetic impurities. The density of states and the ferromagnetic transition temperature of a spin-fermion model applied to DMSs are evaluated using dynamical mean-field theory and Monte Carlo (MC) calculations. It is shown that the addition of a square-well-like attractive potential can generate an IB at small enough Mn doping x for values of the p-d exchange J that are not strong enough to generate one by themselves. We observe that the IB merges with the VB when x>=xc where xc is a function of J and the Coulomb strength V. Using MC simulations, we demonstrate that the range of the Coulomb attraction plays an important role. While the on-site attraction, which has been used in previous numerical simulations, effectively renormalizes J for all values of x, an unphysical result, a nearest-neighbor range attraction renormalizes J only at very low dopings, i.e., until the bound holes wave functions start to overlap. Thus, our results indicate that the Coulomb attraction can be neglected to study Mn-doped GaSb, GaAs, and GaP in the relevant doping regimes, but it should be included in the case of Mn-doped GaN, which is expected to be in the IB regime.
Exclusive radiative Higgs decays as probes of light-quark Yukawa couplings
NASA Astrophysics Data System (ADS)
König, Matthias; Neubert, Matthias
2015-08-01
We present a detailed analysis of the rare exclusive Higgs boson decays into a single vector meson and a photon and investigate the possibility of using these processes to probe the light-quark Yukawa couplings. We work with an effective Lagrangian with modified Higgs couplings to account for possible new-physics effects in a model-independent way. The h ? V? decay rate is governed by the destructive interference of two amplitudes, one of which involves the Higgs coupling to the quark anti-quark pair inside the vector meson. We derive this amplitude at next-to-leading order in ? s using QCD factorization, including the resummation of large logarithmic corrections and accounting for the effects of flavor mixing. The high factorization scale ? ˜ m h ensures that our results are rather insensitive to the hadronic parameters characterizing the light-cone distribution amplitude of the vector meson. The second amplitude arises from the loop-induced effective h?? * and h?Z * couplings, where the off-shell gauge boson converts into the vector meson. We devise a strategy to eliminate theoretical uncertainties related to this amplitude to almost arbitrary precision. This opens up the possibility to probe for modifications of the c- and b-quark Yukawa couplings and modifications of the s-quark Yukawa coupling in the high-luminosity LHC run. In particular, we show that measurements of the ratios Br( h ? ?( nS) ?)/Br( h ? ??) and can provide complementary information on the real and imaginary parts of the b-quark Yukawa coupling. More accurate measurements would be possible at a future 100 TeV proton-proton collider.
Higgs boson mass and sparticle spectroscopy in Yukawa unified SUSY SO(10)
Shafi, Qaisar
2012-07-27
We employ third family Yukawa unification, predicted by simple supersymmetric SO(10) models, to estimate the lightest MSSM Higgs boson mass. For {mu} > 0 (or {mu} < 0) and m{sub t} = 173.1GeV, the Higgs mass is estimated to lie close to 123-124 GeV. The theoretical uncertainty in this estimate is {+-}3 GeV. We highlight some LHC testable benchmark points which also display the presence of neutralino-stau coannihilation channel.
Neutralino dark matter and other LHC predictions from quasi Yukawa unification
NASA Astrophysics Data System (ADS)
Shafi, Qaisar; Tany?ld?z?, ?ükrü Hanif; Ün, Cem Salih
2015-11-01
We explore the dark matter and LHC implications of t - b - ? quasi Yukawa unification in the framework of supersymmetric models based on the gauge symmetry G = SU (4)c × SU (2)L × SU (2)R. The deviation from exact Yukawa unification is quantified by a dimensionless parameter C (| C | ? 0.2), such that the Yukawa couplings at MGUT are related by yt :yb :y? = | 1 + C | : | 1 - C | : | 1 + 3 C |. In contrast to earlier studies which focused on universal gaugino masses, we consider non-universal gaugino masses at MGUT that are compatible with the gauge symmetry G. Our results reveal a variety of neutralino dark matter scenarios consistent with the observations. These include stau and chargino coannihilation scenarios, the A-resonance scenario, as well as Higgsino dark matter solutions which are more readily probed by direct detection searches. The gluino mass is found to be ? 4 TeV, the stop mass is ? 2 TeV, while the first two family squarks and sleptons are of order 4-5 TeV and 3 TeV respectively.
Supersymmetric Grand Unified Theories: Two Loop Evolution of Gauge and Yukawa Couplings
V. Barger; M. S. Berger; P. Ohmann
1992-09-14
We make a numerical study of gauge and Yukawa unification in supersymmetric grand unified models and examine the quantitative implications of fermion mass ans\\"{a}tze at the grand unified scale. Integrating the renormalization group equations with $\\alpha _1(M_Z)$ and $\\alpha _2(M_Z)$ as inputs, we find $\\alpha _3(M_Z)\\simeq 0.111 (0.122)$ for $M_{SUSY}^{}=m_t$ and $\\alpha _3(M_Z)\\simeq 0.106 (0.116)$ for $M_{SUSY}^{}=1$ TeV at one-loop (two-loop) order. Including $b$ and $\\tau $ Yukawa couplings in the evolution, we find an upper limit $m_t\\ltap 200$ GeV from Yukawa unification. For given $m_t\\ltap 175$ GeV, there are two solutions for $\\beta$, one with $\\tan \\beta > m_t/m_b$, and one with $\\sin \\beta \\simeq 0.78(m_t/150\\;{\\rm GeV})$. Taking a popular ansatz for the mass matrices at the unified scale, we obtain a lower limit on the top quark mass of $m_t\\gtap 150 (115)$ GeV for $\\alpha _3(M_Z)=0.11 (0.12)$ and an upper limit on the supersymmetry parameter $\\tan \\beta \\ltap 50$ if $\\alpha _3(M_Z)=0.11$. The evolution of the quark mixing matrix elements is also evaluated.
Beyond the God-particle at the Tevatron: detecting gluinos from Yukawa-unified SUSY
Baer, Howard; Sekmen, Sezen; Summy, Heaya
2009-01-01
Simple SUSY GUT models based on the gauge group SO(10) require t-b-\\tau Yukawa coupling unification, in addition to gauge coupling and matter unification. The Yukawa coupling unification places strong constraints on the expected superparticle mass spectrum, with scalar masses \\sim 10 TeV while gluino masses are much lighter: in the 300--500 GeV range. The very heavy squarks suppress negative interference in the q\\bar{q}\\to\\tg\\tg cross section, leading to a large enhancement in production rates. The gluinos decay almost always via three-body modes into a pair of b-quarks, so we expect at least four b-jets per signal event. We investigate the capability of Fermilab Tevatron collider experiments to detect gluino pair production in Yukawa-unified SUSY. By requiring events with large missing E_T and \\ge 2 or 3 tagged b-jets, we find a 5\\sigma reach in excess of m_{\\tg}\\sim 400 GeV for 5 fb^{-1} of data. This range in m_{\\tg} is much further than the conventional Tevatron SUSY reach, and should cut a significant sw...
Tracing the Gauge Origin of Yukawa and Higgs Parameters Beyond the Standard Model
NASA Astrophysics Data System (ADS)
Lorenzo Díaz-Cruz, J.
We discuss possible realizations of the hypothesis that all the fundamental interactions of the elementary particles should be of gauge type, including the Yukawa and Higgs ones. In the minimal SUSY extension of the standard model, where the quartic Higgs couplings are "gauged" through the D-terms, it is also possible to generate radiatively the Yukawa matrices for the light generations, thus expressing them as functions of gauge couplings. The program can also be applied to the SUSY LR model, where the possibility to induce radiatively the mixing angles, can help to make viable the parity solution to the strong CP problem. The superpotential of the model still includes some non-gauge couplings, namely, the Yukawa constants for the third generation and the trilinear terms ??L??R and ? '?c L? ?c R, involving the Higgs bi-doublet (?) and two pairs of doublets (?L, ?R and their conjugates). Additional progress to relate these parameters to gauge couplings, can be made by embedding the LR model within a SUSY model SU(4)W×U(1)B-L in five dimensions, where the Higgs bi-doublet is identified as the extra component of the 5D gauge field.
Aftershock triggering by complete Coulomb stress changes
Kilb, Debi; Gomberg, J.; Bodin, P.
2002-01-01
We examine the correlation between seismicity rate change following the 1992, M7.3, Landers, California, earthquake and characteristics of the complete Coulomb failure stress (CFS) changes (??CFS(t)) that this earthquake generated. At close distances the time-varying "dynamic" portion of the stress change depends on how the rupture develops temporally and spatially and arises from radiated seismic waves and from permanent coseismic fault displacement. The permanent "static" portion (??CFS) depends only on the final coseismic displacement. ??CFS diminishes much more rapidly with distance than the transient, dynamic stress changes. A common interpretation of the strong correlation between ??CFS and aftershocks is that load changes can advance or delay failure. Stress changes may also promote failure by physically altering properties of the fault or its environs. Because it is transient, ??CFS(t) can alter the failure rate only by the latter means. We calculate both ??CFS and the maximum positive value of ??CFS(t) (peak ??CFS(t)) using a reflectivity program. Input parameters are constrained by modeling Landers displacement seismograms. We quantify the correlation between maps of seismicity rate changes and maps of modeled ??CFS and peak ??CFS(t) and find agreement for both models. However, rupture directivity, which does not affect ??CFS, creates larger peak ??CFS(t) values northwest of the main shock. This asymmetry is also observed in seismicity rate changes but not in ??CFS. This result implies that dynamic stress changes are as effective as static stress changes in triggering aftershocks and may trigger earthquakes long after the waves have passed.
Cold chemistry with electronically excited Ca{sup +} Coulomb crystals
Gingell, Alexander D.; Bell, Martin T.; Oldham, James M.; Softley, Timothy P.; Harvey, Jeremy N.
2010-11-21
Rate constants for chemical reactions of laser-cooled Ca{sup +} ions and neutral polar molecules (CH{sub 3}F, CH{sub 2}F{sub 2}, or CH{sub 3}Cl) have been measured at low collision energies (
Cholesteric order in systems of helical Yukawa rods
H. H. Wensink; G. Jackson
2010-04-13
We consider the interaction potential between two chiral rod-like colloids which consist of a thin cylindrical backbone decorated with a helical charge distribution on the cylinder surface. For sufficiently slender coiled rods a simple scaling expression is derived which links the chiral `twisting' potential to the intrinsic properties of the particles such as the coil pitch, charge density and electrostatic screening parameter. To predict the behavior of the macroscopic cholesteric pitch we invoke a simple second-virial theory generalized for weakly twisted director fields. While the handedness of the cholesteric phase for weakly coiled rods is always commensurate with that of the internal coil, more strongly coiled rods display cholesteric order with opposite handedness. The correlation between the symmetry of the microscopic helix and the macroscopic cholesteric director field is quantified in detail. Mixing helices with sufficiently disparate lengths and coil pitches gives rise to a demixing of the uniform cholesteric phase into two fractions with a different macroscopic pitch. Our findings are consistent with experimental results and could be helpful in interpreting experimental observations in systems of cellulose and chitin microfibers, DNA and {\\em fd} virus rods.
The ice-limit of Coulomb gauge Yang-Mills theory
Thomas Heinzl; Anton Ilderton; Kurt Langfeld; Martin Lavelle; David McMullan
2008-07-29
In this paper we describe gauge invariant multi-quark states generalising the path integral framework developed by Parrinello, Jona-Lasinio and Zwanziger to amend the Faddeev-Popov approach. This allows us to produce states such that, in a limit which we call the ice-limit, fermions are dressed with glue exclusively from the fundamental modular region associated with Coulomb gauge. The limit can be taken analytically without difficulties, avoiding the Gribov problem. This is llustrated by an unambiguous construction of gauge invariant mesonic states for which we simulate the static quark--antiquark potential.
Transition from Coulomb Blockade to Resonant Transmission in a MoS2 Nanoribbon
NASA Astrophysics Data System (ADS)
Li, Yanjing; Mason, Nadya
2014-03-01
We have measured a side-gated nanoribbon of MoS2 at low temperature, and observed the transition from Coulomb blockade to resonant transmission when the Fermi level is tuned with a gate. We show that near the crossover between these regimes, the entire nanoribbon acts as a single quantum dot. Our findings may shed light on quasi-ballistic transport in the material. We also discuss the quantum dot formation in terms of a substrate-induced disorder potential, and consider other possible origins of disorder.
Magnetic field effect on the Coulomb interaction of acceptors in semimagnetic quantum dot
NASA Astrophysics Data System (ADS)
Kalpana, P.; Merwyn, A.; Reuben, Jasper D.; Nithiananthi, P.; Jayakumar, K.
2015-06-01
The Coulomb interaction of holes in a Semimagnetic Cd1-xMnxTe / CdTe Spherical and Cubical Quantum Dot (SMQD) in a magnetic field is studied using variational approach in the effective mass approximation. Since these holes in QD show a pronounced collective behavior, while distinct single particle phenomena is suppressed, their interaction in confined potential becomes very significant. It has been observed that acceptor-acceptor interaction is more in cubical QD than in spherical QD which can be controlled by the magnetic field. The results are presented and discussed.
NASA Astrophysics Data System (ADS)
Schütte, Bernd; Arbeiter, Mathias; Fennel, Thomas; Jabbari, Ghazal; Gokhberg, Kirill; Kuleff, Alexander I.; Vrakking, Marc J. J.; Rouzée, Arnaud
2015-05-01
Interatomic Coulombic decay (ICD) describes a process, where an excited atom relaxes by transferring its energy to an atom in the environment that gets ionized. So far, ICD has been observed following XUV ionization or excitation of clusters. Here we present novel results of an intracluster Coulombic decay mechanism induced by intense NIR pulses and following Rydberg atom formation in the generated nanoplasma. When a highly-excited Rydberg atom relaxes to its ground state by transferring its excess energy to a weakly bound electron in the environment, electrons with kinetic energies close to the atomic ionization potential are emitted. We show evidence for such an intracluster Coulombic decay process that leaves clear signatures in the electron kinetic energy spectra. ICD is time-resolved in a pump-probe experiment, where a weak probe pulse depopulates the excited states, leading to a quenching of the ICD signal. We find a decay time of 87 ps, which is siginificantly longer than for previous ICD observations, where inner-shell holes were created by XUV pulses. Intracluster Coulombic decay is found to be a generic process that takes places in atomic and molecular clusters and at different wavelengths. It may play an important role in biological systems and in astronomical plasmas. Previous affiliation: Max-Born-Institut, Berlin, Germany.
NASA Astrophysics Data System (ADS)
Kawata, Masaaki; Mikami, Masuhiro; Nagashima, Umpei
2002-02-01
A computationally efficient method was developed for calculating Coulomb interactions in three-dimensional (3D) systems with two-dimensional (2D) periodicity; the 2D particle-mesh Ewald (2D-PME) method we previously developed was extended. The formulation and numerical algorithms are described in detail for calculating the Coulomb potential energy, the Coulomb force, and the Coulomb component of the pressure tensor. Computational efficiency and accuracy of the 2D-PME method were evaluated for two water systems with 2D periodicity in the x and y directions and with non-periodicity in the z direction. Compared with exact results calculated by using the original 2D Ewald summations, the 2D-PME method yielded significantly accurate calculations, similar to the computationally efficient method we previously developed for calculating 2D Ewald summations (2D-EW method). For a given accuracy, the 2D-PME method was faster than the 2D-EW method for the water systems we examined. The computational effort of the 2D-PME method decreases as the computationally efficiency of the Fourier transforms used in the 2D-PME method increases. The 2D-PME method is therefore promising for accelerating molecular dynamics and Monte Carlo simulations for 3D systems with 2D periodicity.
Modified Coulomb-Dipole Theory for 2e Photoionization
NASA Technical Reports Server (NTRS)
2004-01-01
In the light of recent experiment on 2e photoionization of Li near threshold, we have considered a modification of the Coulomb-dipole theory, retaining the basic assumption that the threshold is dominated by asymmetric events in phase space [implies r(sub 1), k(sub 1)) greater than or equal to 2(r(sub 2), k(sub )]. In this region [in a collinear model, 2/r(sub 12) approached + 2/(r(sub 1)+r(sub 2)] the interaction reduces to V(rIsub 1) is greater than or equal to 2r(sub 2) is identically equal to [(-Z/r(sub 2)-(A-1)/r(sub 1)] + [(-2r(sub 2)/r(sub 1 exp 2)] is identically equal to V(sub c)+[V(sub d)]. For two electron emission Z = 2, thus both electrons see a Coulomb potential (V(sub c)) asymptotically, albeit each seeing a different charge. The residual potential (V(sub d)) is dipole in character. Writing the total psi = psi (sub c) + psi(sub d) = delta psi, and noting that. (T+V(sub c)-E)psy(sub c) = 0 and (T+V(sub c))psi(sub d) = 0 can be solved exactly, we find, substituting psi into the complete Schrod. Eq., that delta psi = -(H-E)(exp -1)(V(sub d) psi(sub 0)+V(sub c psi (sub 1). Using the fact that the absolute value of V(sub c) is much more than the absolute value of V(sub d) in almost all of configuration space, we can replace H by H(sub 0) in 9H-E)(exp -1) to obtain an improved approximation psi (improved) = psi(sub c) + psi(sub d) -(H(sub 0)-E)(exp -1) (V(sub c) psi (sub 0) + V(sub c) psi(sub 1). Here's the Green's function (H(sub 0)-E)(exp -1), can be exhibited explicitly, but the last term in psi (improved) is small, compared to the first two terms. Inserting them into the transition matrix element, which one handles in the usual way, we obtain in the limit E approaches 0, the threshold law: Q(E) alpha E + M(E)E(exp 5/4) + higher order (Eq. 1a). The modulation function, M(E), is a well-defined (but very non-trivial integral, but it is expected to be well approximated by a sinusoidal function containing a dipole phase term (M(E) = c sin[alpha log (E) + micron] (Eq. 1b). Experimental results show definite modulations, and are well fitted by Eqs (1).
Constituent gluon content of the static quark-antiquark state in Coulomb gauge
Greensite, J.; Olejnik, S.
2009-06-01
Motivated by the gluon-chain model of flux tube formation, we compute and diagonalize the transfer matrix in lattice SU(2) gauge theory for states containing heavy static quark-antiquark sources, with separations up to one Fermi. The elements of the transfer matrix are calculated by variational Monte Carlo methods, in a basis of states obtained by acting on the vacuum state with zero-, one-, and two-gluon operators in Coulomb gauge. The color Coulomb potential is obtained from the zero-gluon to zero-gluon element of the transfer matrix, and it is well known that while this potential is asymptotically linear, it has a slope which is 2 to 3 times larger than the standard asymptotic string tension. We show that the addition of one- and two-gluon states results in a potential which is still linear, but the disagreement with the standard asymptotic string tension is reduced to 38% for the variational states used in this study, at the largest value of {beta}=4/g{sup 2}=2.4 considered.
Dynamical properties of non-ideal plasma on the basis of effective potentials
Ramazanov, T. S.; Kodanova, S. K.; Moldabekov, Zh. A.; Issanova, M. K.
2013-11-15
In this work, stopping power has been calculated on the basis of the Coulomb logarithm using the effective potentials. Calculations of the Coulomb logarithm and stopping power for different interaction potentials and degrees of ionization are compared. The comparison with the data of other theoretical and experimental works was carried out.
Thermodynamic functions of the hcp Coulomb crystal lattice
NASA Astrophysics Data System (ADS)
Kozhberov, A. A.; Baiko, D. A.
2015-10-01
One-component Coulomb crystals of ions with hexagonal close-packed (hcp) lattice likely form in the crust of strongly-magnetized neutron stars (magnetars). In this work we present a detailed study of vibration modes and thermodynamic properties of such crystals in a wide range of temperatures at zero magnetic field. In contrast to typically considered lattices, the phonon spectrum of the system exhibits a peculiar crossing of the acoustic modes near the Brillouin zone center in certain directions of the wavevector. It is demonstrated that in the field-free regime the Helmholtz free energy of the hcp Coulomb crystal is always higher than those of the Coulomb crystals with body-centered cubic and face-centered cubic lattices. The results of our numerical calculations are fitted by simple analytic expressions.
Weak interaction rate Coulomb corrections in big bang nucleosynthesis
Smith, Christel J.; Fuller, George M.
2010-03-15
We have applied a fully relativistic Coulomb wave correction to the weak reactions in the full Kawano/Wagoner big bang nucleosynthesis (BBN) code. We have also added the zero-temperature radiative correction. We find that using this higher accuracy Coulomb correction results in good agreement with previous work, giving only a modest {approx}0.04% increase in helium mass fraction over correction prescriptions applied previously in BBN calculations. We have calculated the effect of these corrections on other light element abundance yields in BBN, and we have studied these yields as functions of electron neutrino lepton number. This has allowed insights into the role of the weak neutron-proton interconversion processes in the setting of the neutron-to-proton ratio during the BBN epoch. We find that the lepton capture processes' contributions to this ratio are only second order in the Coulomb correction.
Confining dyon-antidyon Coulomb liquid model. I.
NASA Astrophysics Data System (ADS)
Liu, Yizhuang; Shuryak, Edward; Zahed, Ismail
2015-10-01
We revisit the dyon-antidyon liquid model for the Yang-Mills confining vacuum discussed by Diakonov and Petrov, by retaining the effects of the classical interactions mediated by the streamline between the dyons and antidyons. In the SU(2) case the model describes a 4-component strongly interacting Coulomb liquid in the center symmetric phase. We show that in the linearized screening approximation, the streamline interactions yield Debye-Huckel-type corrections to the bulk parameters, such as the pressure and densities, but do not alter significantly the large-distance behavior of the correlation functions in leading order. The static scalar and charged structure factors are consistent with a plasma of a dyon-antidyon liquid with a Coulomb parameter ?D D ¯?1 in the dyon-antidyon channel. Heavy quarks are still linearly confined and the large spatial Wilson loops still exhibit area laws in leading order. The t' Hooft loop is shown to be one modulo Coulomb corrections.
On Dirac-Coulomb problem in (2+1) dimensional space-time and path integral quantization
Haouat, S.; Chetouani, L.
2012-06-15
The problem of Dirac particle interacting with Coulomb potential in (2+1) dimensions is formulated in the framework of super-symmetric path integrals where the spin degrees of freedom are described by odd Grassmannian variables. The relative propagator is expressed through Cartesian coordinates in a Hamiltonian form by the use of an adequate transformation. The passage to the polar coordinates permitted us to calculate the fixed energy Green's function and to extract bound states and associating wave functions.
Quantum calculations of Coulomb reorientation for sub-barrier fusion
Simenel, C; De France, G; Simenel, Cedric; Chomaz, Philippe; France, Gilles De
2004-01-01
Classical mechanics and Time Dependent Hartree-Fock (TDHF) calculations of heavy ions collisions are performed to study the rotation of a deformed nucleus in the Coulomb field of a collision partner. We show that this Coulomb reorientation is independent on the charges and the relative energy of the partners. It only depends upon the deformations and the respective masses. Furthermore this reorientation modifies strongly the fusion cross-section around the barrier for light deformed nuclei on heavy collision partners. For such nuclei a hindrance of the sub-barrier fusion is predicted.
Primary Thermometry in the Intermediate Coulomb Blockade Regime
NASA Astrophysics Data System (ADS)
Feshchenko, A. V.; Meschke, M.; Gunnarsson, D.; Prunnila, M.; Roschier, L.; Penttilä, J. S.; Pekola, J. P.
2013-10-01
We investigate Coulomb blockade thermometers (CBT) in an intermediate temperature regime, where measurements with enhanced accuracy are possible due to the increased magnitude of the differential conductance dip. Previous theoretical results show that corrections to the half width and to the depth of the measured conductance dip of a sensor are needed, when leaving the regime of weak Coulomb blockade towards lower temperatures. In the present work, we demonstrate experimentally that the temperature range of a CBT sensor can be extended by employing these corrections without compromising the primary nature or the accuracy of the thermometer.
Convergence of Feynman integrals in Coulomb gauge QCD
Andraši, A.; Taylor, J.C.
2014-12-15
At 2-loop order, Feynman integrals in the Coulomb gauge are divergent over the internal energy variables. Nevertheless, it is known how to calculate the effective action, provided that the external gluon fields are all transverse. We show that, for the two-gluon Greens function as an example, the method can be extended to include longitudinal external fields. The longitudinal Greens functions appear in the BRST identities. As an intermediate step, we use a flow gauge, which interpolates between the Feynman and Coulomb gauges.
Coulomb instability of hot nuclei with derivative scalar coupling
NASA Astrophysics Data System (ADS)
Song, H. Q.; Qian, Z. X.; Su, R. K.
1994-06-01
The relativistic nuclear mean field model with derivative scalar coupling suggested by Zimanyi and Moszkowski is extended to asymmetric nuclear matter by including the ? meson degree of freedom in the Lagrangian. The extended model is then used to studying the Coulomb instability of asymmetric nuclear matter at finite temperature. The critical temperature for the liquid-gas phase transition in nuclear matter and its dependence on the asymmetry parameter are calculated. The limiting temperature Tlim, which reflects Coulomb instability of hot nuclei is studied. The calculated results are compared with those given by quantum hadrodynamics (QHD) models.
Coulomb instability of hot nuclei with derivative scalar coupling
Song, H.Q.; Qian, Z.X.; Su, R.K. , P.O. Box 8730, Beijing Institute of Nuclear Research, Academia Sinica, P.O. Box 800204, Shanghai 201800 Department of Physics, Fudan University, Shanghai 200433 T. D. Lee Physics Laboratory, Fudan University, Shanghai 200433 )
1994-06-01
The relativistic nuclear mean field model with derivative scalar coupling suggested by Zimanyi and Moszkowski is extended to asymmetric nuclear matter by including the [rho] meson degree of freedom in the Lagrangian. The extended model is then used to studying the Coulomb instability of asymmetric nuclear matter at finite temperature. The critical temperature for the liquid-gas phase transition in nuclear matter and its dependence on the asymmetry parameter are calculated. The limiting temperature [ital T][sub lim], which reflects Coulomb instability of hot nuclei is studied. The calculated results are compared with those given by quantum hadrodynamics (QHD) models.
Coulomb impurity effect on electrically induced Dirac bound states in graphene
NASA Astrophysics Data System (ADS)
Lee, C. M.; Chan, K. S.
2015-12-01
Using the massless Dirac-Weyl model for monolayer graphene sheet, we study the low-lying spectra of a single Dirac electron system bound to an on-center positively charged Coulomb impurity, under both electrostatic potential and magnetic field. Numerical results obtained from diagonalization show that, the increase of the electrostatic potential causes the low-lying states to evolve from one Landau-type plateau to the higher ones, and the whole spectra exhibit similar features with slight shifts in eigenenergies when the on-center impurity is considered. Electrostatic-potential dependent optical spectra with their corresponding absorption coefficients as functions of incident photon energies for transitions between low-lying states are presented.
Two-dimensional and three-dimensional Coulomb clusters in parabolic traps
D'yachkov, L. G. Myasnikov, M. I.; Petrov, O. F.; Hyde, T. W.; Kong, J.; Matthews, L.
2014-09-15
We consider the shell structure of Coulomb clusters in an axially symmetric parabolic trap exhibiting a confining potential U{sub c}(?,z)=(m?{sup 2}/2)(?{sup 2}+?z{sup 2}). Assuming an anisotropic parameter ??=?4 (corresponding to experiments employing a cusp magnetic trap under microgravity conditions), we have calculated cluster configurations for particle numbers N?=?3 to 30. We have shown that clusters with N???12 initially remain flat, transitioning to three-dimensional configurations as N increases. For N?=?8, we have calculated the configurations of minimal potential energy for all values of ? and found the points of configuration transitions. For N?=?13 and 23, we discuss the influence of both the shielding and anisotropic parameter on potential energy, cluster size, and shell structure.
Heat transfer coefficients in two-dimensional Yukawa systems (numerical simulations)
Khrustalyov, Yu. V. Vaulina, O. S.
2013-05-15
New data on heat transfer in two-dimensional Yukawa systems have been obtained. The results of a numerical study of the thermal conductivity for equilibrium systems with parameters close to the conditions of laboratory experiments in dusty plasma are presented. The Green-Kubo relations are used to calculate the heat transfer coefficients. The influence of dissipation (internal friction) on the heat transfer processes in nonideal systems is studied. New approximations are proposed for the thermal conductivity and diffusivity for nonideal dissipative systems. The results obtained are compared with the existing experimental and numerical data.
Non-Perturbative Calculation of the Scalar Yukawa Theory in Four-Body Truncation
Yang Li; V. A. Karmanov; P. Maris; James P. Vary
2015-03-24
The quenched scalar Yukawa theory is solved in the light-front Tamm-Dancoff approach including up to four constituents (one scalar nucleon, three scalar pions). The Fock sector dependent renormalization is implemented. By studying the Fock sector norms, we find that the lowest two Fock sectors dominate the state even in the large-coupling region. The one-body sector shows convergence with respect to the Fock sector truncation. However, the four-body norm exceeds the three-body norm at the coupling $\\alpha \\approx 1.7$.
Numerical simulations of thermal conductivity in dissipative two-dimensional Yukawa systems.
Khrustalyov, Yu V; Vaulina, O S
2012-04-01
Numerical data on the heat transfer constants in two-dimensional Yukawa systems were obtained. Numerical study of the thermal conductivity and diffusivity was carried out for the equilibrium systems with parameters close to conditions of laboratory experiments with dusty plasma. For calculations of heat transfer constants the Green-Kubo formulas were used. The influence of dissipation (friction) on the heat transfer processes in nonideal systems was investigated. The approximation of the coefficient of thermal conductivity is proposed. Comparison of the obtained results to the existing experimental and numerical data is discussed. PMID:22680584
Probing the Charm Quark Yukawa Coupling in Higgs+Charm Production
NASA Astrophysics Data System (ADS)
Brivio, Ilaria; Goertz, Florian; Isidori, Gino
2015-11-01
We propose a new method for determining the coupling of the Higgs boson to charm quarks, via Higgs production in association with a charm-tagged jet: p p ?h c . As a first estimate, we find that at the LHC with 3000 fb-1 , it should be possible to derive a constraint of order one, relative to the standard model (SM) value of the charm Yukawa coupling. As a by-product of this analysis, we present an estimate of the exclusive p p ?h D(*) electroweak cross section. Within the SM, the latter turns out to be not accessible at the LHC even in the high-luminosity phase.
Infra-Red Stable Fixed Points of Yukawa Couplings in Supersymmetric Models
Allanach, Benjamin C
1997-01-01
We provide the solutions of the fixed point conditions of the Yukawa sector for a large class of N=1 supersymmetric theories including the minimal and next-to-minimal supersymmetric standard models and their grand unified and other extensions. We also introduce a test which can discriminate between infra-red stable, infra-red unstable and saddle point solutions, and illustrate our methods with the example of the next-to-minimal supersymmetric standard model. We show that in this case, the fixed point prediction of the top quark mass is equivalent to that of the minimal supersymmetric standard model, supporting previous numerical analyses.
Decay of a Yukawa fermion at finite temperature and applications to leptogenesis
Kiessig, Clemens P.; Pluemacher, Michael; Thoma, Markus H.
2010-08-01
We calculate the decay rate of a Yukawa fermion in a thermal bath using finite-temperature cutting rules and effective Green's functions according to the hard thermal loop resummation technique. We apply this result to the decay of a heavy Majorana neutrino in leptogenesis. Compared to the usual approach where thermal masses are inserted into the kinematics of final states, we find that deviations arise through two different leptonic dispersion relations. The decay rate differs from the usual approach by more than 1 order of magnitude in the temperature range which is interesting for the weak washout regime. We discuss how to arrive at consistent finite-temperature treatments of leptogenesis.
One loop radiative corrections to the translation-invariant noncommutative Yukawa Theory
Karim Bouchachia; Smain Kouadik; Mahmoud Hachemane; Manfred Schweda
2015-02-10
We elaborate in this paper a translation-invariant model for fermions in 4-dimensional noncommutative Euclidean space. The construction is done on the basis of the renormalizable noncommutative translation-invariant Phi4 theory introduced by R. Gurau et al. We combine our model with the scalar model, in order to study the noncommutative pseudo-scalar Yukawa theory. After we derive the Feynman rules of the theory, we perform an explicit calculation of the quantum corrections at one loop level to the propagators and vertices.
One loop radiative corrections to the translation-invariant noncommutative Yukawa Theory
NASA Astrophysics Data System (ADS)
Bouchachia, K.; Kouadik, S.; Schweda, M.; Hachemane, M.
2015-09-01
We elaborate in this paper a translation-invariant model for fermions in 4-dimensional noncommutative Euclidean space. The construction is done on the basis of the renormalizable noncommutative translation-invariant {\\varphi }4 theory introduced by Gurau et al. 2009 Commun. Math. Phys. 287 275-90. We combine our model with a scalar model, in order to study the noncommutative pseudo-scalar Yukawa theory. After we derive the Feynman rules of the theory, we perform an explicit calculation of the quantum corrections at one loop level for the propagators and vertices.
Full simulation study of the top Yukawa coupling at the ILC at TeV
NASA Astrophysics Data System (ADS)
Price, T.; Roloff, P.; Strube, J.; Tanabe, T.
2015-07-01
We present a study of the expected precision for the measurement of the top Yukawa coupling, , in collisions at a center-of-mass energy of 1 TeV. Independent analyses of final states containing at least six hadronic jets are performed, based on detailed simulations of SiD and ILD, the two candidate detector concepts for the ILC. We estimate that a statistical precision on of 4.5 % can be obtained with an integrated luminosity of 1 that is split equally between two configurations for the beam polarization , and . This estimate improves to if the 1 sample is assumed to be fully in the configuration.
Constraints on Yukawa-Type Deviations from Newtonian Gravity at 20 Microns
S. J. Smullin; A. A. Geraci; D. M. Weld; J. Chiaverini; S. Holmes; A. Kapitulnik
2006-01-01
Recent theories of physics beyond the standard model have predicted deviations from Newtonian gravity at short distances. In order to test these theories, we have a built an apparatus that can measure attonewton-scale forces between gold masses separated by distances on the order of 25 microns. A micromachined silicon cantilever was used as the force sensor, and its displacement was measured with a fiber interferometer. We have used our measurements to set bounds on the magnitude alpha and length scale lambda of Yukawa-type deviations from Newtonian gravity; our results presented here yield the best experimental limit in the range of lambda=6--20 microns.
Asymptotic freedom for quantum chromodynamics with top yukawa and Higgs interactions
NASA Astrophysics Data System (ADS)
Zimmermann, Wolfhart
1994-01-01
Asymptotic freedom of QCD is extended to the enlarged system including the top Yukawa and Higgs interactions. Necessary and sufficient conditions for asymptotic freedom are given. By expansion with respect to powers of ?, all couplings are determined which are compatible with asymptotic freedom. It is found that the Higgs coupling is a function of the top coupling and that both couplings have upper bounds which correspond to the nontrivial case of reduction. The ultraviolet behavior of the coupling is controlled in all orders of the expansion.
Dark Matter from SUGRA GUTs: mSUGRA, NUSUGRA and Yukawa-unified SUGRA
Baer, Howard
2009-09-08
Gravity-mediated SUSY breaking models with R-parity conservation give rise to dark matter in the universe. I review neutralino dark matter in the minimal supergravity model (mSUGRA), models with non-universal soft SUSY breaking terms (NUSUGRA) which yield a well-tempered neutralino, and models with unified Yukawa couplings at the GUT scale (as may occur in an SO(10) SUSY GUT theory). These latter models have difficulty accomodating neutralino dark matter, but work very well if the dark matter particles are axions and axinos.
Probing the Charm Quark Yukawa Coupling in Higgs+Charm Production.
Brivio, Ilaria; Goertz, Florian; Isidori, Gino
2015-11-20
We propose a new method for determining the coupling of the Higgs boson to charm quarks, via Higgs production in association with a charm-tagged jet: pp?hc. As a first estimate, we find that at the LHC with 3000??fb^{-1}, it should be possible to derive a constraint of order one, relative to the standard model (SM) value of the charm Yukawa coupling. As a by-product of this analysis, we present an estimate of the exclusive pp?hD^{(*)} electroweak cross section. Within the SM, the latter turns out to be not accessible at the LHC even in the high-luminosity phase. PMID:26636844
Weak formulations and solution multiplicity of equilibrium configurations with Coulomb friction
Bostan, Mihai
Weak formulations and solution multiplicity of equilibrium configurations with Coulomb friction configurations of elastic struc- tures in contact with Coulomb friction. We obtain a variational formulation configurations with arbitrary small friction coefficients. We illustrate the result in two space dimensions
Predicting Freezing for Some Repulsive Potentials
Khrapak, S. A.; Morfill, G. E.
2009-12-18
We propose a simple method to approximately predict the freezing (fluid-solid) phase transition in systems of particles interacting via purely repulsive potentials. The method is based on the striking universality of the freezing curve for the model Yukawa and inverse-power-law interactions. This method is applied to draw an exemplary phase diagram of complex plasmas. We suggest that it can also be used to locate freezing transition in other substances with similar properties of interaction.
Finiteness of the Coulomb gauge QCD perturbative effective action
A. Andrasi; J. C. Taylor
2015-04-16
At 2-loop order in the Coulomb gauge, individual Feynman graphs contributing to the effective action have energy divergences. It is proved that these cancel in suitable combinations of graphs. This has previously been shown only for transverse external fields. The calculation results in a generalization of the Christ-Lee term which was inserted into the Hamiltonian.
Coulomb corrections to superallowed beta decay in nuclei
N. Auerbach
2008-11-28
Corrections to the superallowed beta decay matrix elements are evaluated in perturbation theory using the notion of the isovector monopole resonance. The calculation avoids the separation into different contributions and thus presents a consistent, systematic and more transparent approach. Explicit expressions for the Coulomb correction as a function of mass number A, are given.
Strong impact of protonation and deprotonation on intermolecular Coulombic decay
NASA Astrophysics Data System (ADS)
Kryzhevoi, Nikolai V.; Cederbaum, Lorenz S.
2012-11-01
Intermolecular Coulombic decay (ICD) is an ultrafast relaxation mechanism of a highly excited system embedded in a chemical environment. Our theoretical investigation of ammonia clusters shows that the ICD efficiency can be regulated by protonation or deprotonation. It is suggested that by varying ICD rate through changing the environmental pH value a control over the relaxation dynamics can be achieved.
Experimental Proof of Resonant Auger Decay Driven Intermolecular Coulombic Decay
NASA Astrophysics Data System (ADS)
Trinter, F.; Schöffler, M. S.; Kim, H.-K.; Sturm, F.; Cole, K.; Neumann, N.; Vredenborg, A.; Williams, J.; Bocharova, I.; Guillemin, R.; Simon, M.; Belkacem, A.; Landers, A. L.; Weber, Th; Schmidt-Böcking, H.; Dörner, R.; Jahnke, T.
2014-04-01
Resonant Auger decay driven Intermolecular Coulombic Decay through synchrotron radiation in gas phase carbon monoxided dimers and nitrogen dimers has been studied. We report the first experiment where the low-energy ICD-electron has been measured in coincidence with the ionic fragments and Resonant Auger ICD has been proved experimentally.
The Coulomb problem on a 3-sphere and Heun polynomials
Bellucci, Stefano; Yeghikyan, Vahagn; Yerevan State University, Alex-Manoogian st. 1, 00025 Yerevan
2013-08-15
The paper studies the quantum mechanical Coulomb problem on a 3-sphere. We present a special parametrization of the ellipto-spheroidal coordinate system suitable for the separation of variables. After quantization we get the explicit form of the spectrum and present an algebraic equation for the eigenvalues of the Runge-Lentz vector. We also present the wave functions expressed via Heun polynomials.
Exchange Coulomb interaction in nanotubes: Dispersion of Langmuir waves
Andreev, P A
2015-01-01
Microscopic derivation of the Coulomb exchange interaction for electrons located on the nanotubes is presented. Our derivation is based on the many-particle quantum hydrodynamic method. We demonstrate the role of the curvature of the nanocylinders on the force of the exchange interaction. We calculate corresponding dispersion dependencies for electron oscillations on the nanotubes.
Coulomb Interactions in Hanbury Brown-Twiss Experiments with Electrons
ERIC Educational Resources Information Center
Shen, Kan
2009-01-01
This dissertation examines the effect of Coulomb interactions in Hanbury Brown-Twiss (HBT) type experiments with electrons. HBT experiments deal with intensity interference, which is related to the second-order correlation function of the particle field. This is an extension of the usual amplitude interference experiment, such as Young's…
Coulomb effects on edge scattering in elastic nuclear collisions
Silveira, R. da; Leclercq-Willain, Ch.
2011-04-15
We present a qualitative analysis of the effects of the Coulomb force on the edge scattering produced in elastic nuclear collisions occurring under strong absorption conditions. This analysis is illustrated with several examples of nucleus-nucleus and antiproton-nucleus elastic scattering.
Understanding the accuracy of Nanbu's numerical Coulomb collision operator
Caflisch, Russel
Collisional plasma a b s t r a c t We investigate the accuracy of and assumptions underlying the numerical's operator are argued to be an approximate realization of the CoulombLorentz pitch- angle scattering process, for which an analytical solution for the collision kernel is available. It is demonstrated empirically
Hamiltonian flow in Coulomb gauge Yang-Mills theory
Leder, Markus; Reinhardt, Hugo; Pawlowski, Jan M.; Weber, Axel
2011-01-15
We derive a new functional renormalization group equation for Hamiltonian Yang-Mills theory in Coulomb gauge. The flow equations for the static gluon and ghost propagators are solved under the assumption of ghost dominance within different diagrammatic approximations. The results are compared to those obtained in the variational approach and the reliability of the approximations is discussed.
Compact Collision Kernels for Hard Sphere and Coulomb Cross Sections; Fokker-Planck Coefficients
Chang Yongbin; Shizgal, Bernie D.
2008-12-31
A compact collision kernel is derived for both hard sphere and Coulomb cross sections. The difference between hard sphere interaction and Coulomb interaction is characterized by a parameter {eta}. With this compact collision kernel, the calculation of Fokker-Planck coefficients can be done for both the Coulomb and hard sphere interactions. The results for arbitrary order Fokker-Planck coefficients are greatly simplified. An alternate form for the Coulomb logarithm is derived with concern to the temperature relaxation in a binary plasma.
Li, Bo
Yukawa-field approximation of electrostatic free energy and dielectric boundary force This article.1088/0951-7715/24/11/011 Yukawa-field approximation of electrostatic free energy and dielectric boundary force Hsiao-Bing Cheng1. The electrostatic free energy determines the dielectric boundary force that in turn influences crucially
SOSpin, a C++ library for Yukawa decomposition in $\\mathsf{SO}(2N)$ models
Cardoso, Nuno; Gonçalves, Nuno; Simoes, C
2015-01-01
We present in this paper the SOSpin library, which calculates an analytic decomposition of the Yukawa interactions invariant under any $\\mathsf{SO}(2N)$ group in terms of an $\\mathsf{SU}(N)$ basis. We make use of the oscillator expansion formalism, where the $\\mathsf{SO}(2N)$ spinor representations are expressed in terms of creation and annihilation operators of a Grassmann algebra. These noncommutative operators and their products are simulated in SOSpin through the implementation of doubly-linked-list data structures. These data structures were determinant to achieve a higher performance in the simplification of large products of creation and annihilation operators. We illustrate the use of our library with complete examples of how to decompose Yukawa terms invariant under $\\mathsf{SO}(2N)$ in terms of $\\mathsf{SU}(N)$ degrees of freedom for $N=2$ and $5$. We further demonstrate, with an example for $\\mathsf{SO}(4)$, that higher dimensional field-operator terms can also be processed with our library. Finall...
SOSpin, a C++ library for Yukawa decomposition in SO(2N) models
Nuno Cardoso; David Emmanuel-Costa; Nuno Gonçalves; C. Simoes
2015-10-21
We present in this paper the SOSpin library, which calculates an analytic decomposition of the Yukawa interactions invariant under any SO(2N) group in terms of an SU(N) basis. We make use of the oscillator expansion formalism, where the SO(2N) spinor representations are expressed in terms of creation and annihilation operators of a Grassmann algebra. These noncommutative operators and their products are simulated in SOSpin through the implementation of doubly-linked-list data structures. These data structures were determinant to achieve a higher performance in the simplification of large products of creation and annihilation operators. We illustrate the use of our library with complete examples of how to decompose Yukawa terms invariant under SO(2N) in terms of SU(N) degrees of freedom for N=2 and 5. We further demonstrate, with an example for SO(4), that higher dimensional field-operator terms can also be processed with our library. Finally, we describe the functions available in SOSpin that are made to simplify the writing of spinors and their interactions specifically for SO(10) models.
Upper and lower Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model
P. Gerhold
2010-02-12
Motivated by the advent of the Large Hadron Collider the aim of the present work is the non-perturbative determination of the cutoff-dependent upper and lower mass bounds of the Standard Model Higgs boson based on first principle calculations, in particular not relying on additional information such as the triviality property of the Higgs-Yukawa sector or indirect arguments like vacuum stability considerations. For that purpose the lattice approach is employed to allow for a non-perturbative investigation of a chirally invariant lattice Higgs-Yukawa model, serving here as a reasonable simplification of the full Standard Model, containing only those fields and interactions which are most essential for the intended Higgs boson mass determination. These are the complex Higgs doublet as well as the top and bottom quark fields and their mutual interactions. To maintain the chiral character of the Standard Model Higgs-fermion coupling also on the lattice, the latter model is constructed on the basis of the Neuberger overlap operator, obeying then an exact global lattice chiral symmetry.
A New Approach to Yukawa Textures in Supersymmetric Unified Models With Gauged Family Symmetries
Allanach, Benjamin C; Leontaris, George K; Lola, S
1997-01-01
The origin of texture zeroes in the Yukawa matrices may be accounted for by appealing to a broken gauged family symmetry such as U(1)_X, where such symmetries arise naturally from string theories. In order to improve the predictive power of such models we appeal to quark-lepton unification where additional Clebsch texture zeroes appear, leading to an entirely new class of models. We illustrate these ideas in the context of the Pati-Salam gauge group SU(4)xSU(2)_LxSU(2)_R supplemented by a U(1)_X gauged family symmetry. The gauge symmetries are broken down to those of the minimal supersymmetric standard model which is the effective theory below 10^16 GeV. The combination of the U(1)_X family symmetry and the Pati-Salam gauge group leads to a successful and predictive set of Yukawa textures involving both kinds of texture zeroes. We discuss both symmetric and non-symmetric textures in models of this kind, and in the second case perform a detailed numerical fit to the charged fermion mass and mixing data. Two of...
Dynamical breakdown of Abelian gauge chiral symmetry by strong Yukawa interactions
Benes, Petr; Brauner, Tomas; Hosek, Jiri
2007-03-01
We consider a model with anomaly-free Abelian gauge axial-vector symmetry, which is intended to mimic the standard electroweak gauge chiral SU(2){sub L}xU(1){sub Y} theory. Within this model we demonstrate: (1) Strong Yukawa interactions between massless fermion fields and a massive scalar field carrying the axial charge generate dynamically the fermion and boson proper self-energies, which are ultraviolet-finite and chirally noninvariant. (2) Solutions of the underlying Schwinger-Dyson equations found numerically exhibit a huge amplification of the fermion mass ratios as a response to mild changes of the ratios of the Yukawa couplings. (3) The 'would-be' Nambu-Goldstone boson is a composite of both the fermion and scalar fields, and it gives rise to the mass of the axial-vector gauge boson. (4) Spontaneous breakdown of the gauge symmetry further manifests by mass splitting of the complex scalar and by new symmetry-breaking vertices, generated at one loop. In particular, we work out in detail the cubic vertex of the Abelian gauge boson.
Demonstrating Universal Scaling in Quench Dynamics of a Yukawa One-Component Plasma
Langin, T K; Maksimovic, N; McQuillen, P; Pohl, T; Vrinceanu, D; Killian, T C
2015-01-01
The Yukawa one-component plasma (OCP) is a paradigm model for describing plasmas that contain one component of interest and one or more other components that can be treated as a neutralizing, screening background. In appropriately scaled units, interactions are characterized entirely by a screening parameter, $\\kappa$. As a result, systems of similar $\\kappa$ show the same dynamics, regardless of the underlying parameters (e.g., density and temperature). We demonstrate this behavior using ultracold neutral plasmas (UNP) created by photoionizing a cold ($T\\le10$ mK) gas. The ions in UNP systems are well described by the Yukawa model, with the electrons providing the screening. Creation of the plasma through photoionization can be thought of as a rapid quench from $\\kappa_{0}=\\infty$ to a final $\\kappa$ value set by the electron density and temperature. We demonstrate experimentally that the post-quench dynamics are universal in $\\kappa$ over a factor of 30 in density and an order of magnitude in temperature. R...
Properties of gravitationally equilibrated Yukawa systems—A molecular dynamics study
Charan, Harish; Ganesh, Rajaraman Joy, Ashwin
2014-04-15
Using 2D Molecular Dynamics simulation, the equilibrium and dynamical properties of a gravitationally equilibrated Yukawa liquid are investigated. We observe that due to asymmetry introduced in one direction by gravity, several interesting features arise. For example, for a given value of coupling parameter ?, screening parameter ?, and according to a chosen value of gravitational force g (say in y-direction), the system is seen to exhibit super-, sub- or normal diffusion. Interestingly, x-averaged density profiles, unlike a barotropic fluid, acquires sharp, free surface with scale free linear y-dependence. As can be expected for a system with macroscopic gradients, self-diffusion calculated from Green-Kubo’s formalism does not agree with that obtained from Einstein-Smoluchowski diffusion. A 2D angular-radial pair correlation function g(r, ?) clearly indicates asymmetric features induced by gravity. We observe that due to compression in y-direction, though in liquid state for all values of gravity considered, the transverse mode is found to predominant as compared to the longitudinal mode, leading to a novel Anisotropic Solid-like Yukawa liquid.
Models of Yukawa interaction in the two Higgs doublet model, and their collider phenomenology
Aoki, Mayumi; Kanemura, Shinya; Yagyu, Kei; Tsumura, Koji
2009-07-01
Possible models of Yukawa interaction are discussed in the two Higgs doublet model (THDM) under the discrete symmetry imposed to avoid the flavor changing neutral current at the leading order. It is known that there are four types of such models corresponding to the possible different assignment of charges for the discrete symmetry on quarks and leptons. We first examine the decay properties of Higgs bosons in each type model, and summarize constraints on the models from current experimental data. We then shed light on the differences among these models in collider phenomenology. In particular, we mainly discuss the so-called type-II THDM and type-X THDM. The type-II THDM corresponds to the model with the same Yukawa interaction as the minimal supersymmetric standard model. On the other hand, in the type-X THDM, additional Higgs bosons can predominantly decay into leptons. This scenario may be interesting because of the motivation for a light charged Higgs boson scenario such as in the TeV-scale model of neutrinos, dark matter, and baryogenesis. We study how we can distinguish the type-X THDM from the minimal supersymmetric standard model at the Large Hadron Collider and the International Linear Collider.
Perturbativity limits for scalar minimal dark matter with Yukawa interactions: Septuplet
NASA Astrophysics Data System (ADS)
Cai, Chengfeng; Huang, Ze-Min; Kang, Zhaofeng; Yu, Zhao-Huan; Zhang, Hong-Hao
2015-12-01
The candidate of minimal dark matter (MDM) is limited if one demands perturbativity up to a very high scale, and it was believed that the MDM model with a real scalar septuplet could keep perturbative up to the Planck or grand unified theory scale. In this work we point out that it is not true after taking into account the running of the quartic self-couplings of the scalar septuplet. For the septuplet mass around 10 TeV, which is suggested by the observed dark matter relic abundance, these couplings would hit the Landau pole at a scale ˜108- 109 GeV , much lower than the Planck scale. We attempt to push up the Landau pole scale as high as possible by proposing an extension with extra Yukawa interactions of the septuplet. We find that in principle the Landau pole could be deferred to a scale of ˜1014 GeV if one could tolerate a serious fine-tuning of the initial condition of the Yukawa coupling. Moreover, if the MDM particle mass could be relaxed to ˜108 GeV , which would need some nonthermal production mechanisms to give a correct relic abundance, the Landau pole scale could be pushed up above the Planck scale.
Perturbativity Limits for Scalar Minimal Dark Matter with Yukawa Interactions: Septuplet
Chengfeng Cai; Ze-Min Huang; Zhaofeng Kang; Zhao-Huan Yu; Hong-Hao Zhang
2015-10-12
The candidate of minimal dark matter (MDM) is limited if one demands perturbativity up to a very high scale, and it was believed that the MDM model with a real scalar septuplet could keep perturbative up to the Planck or GUT scale. In this work we point out that it is not true after taking into account the running of the quartic self-couplings of the scalar septuplet. For the septuplet mass around $10$ TeV, which is suggested by the observed dark matter relic abundance, these couplings would hit the Landau pole at a scale $\\sim 10^8-10^9$ GeV, much lower than the Planck scale. We attempt to push up the Landau pole scale as high as possible by proposing an extension with extra Yukawa interactions of the septuplet. We find that in principle the Landau pole could be deferred to a scale of $\\sim 10^{14}$ GeV if one could tolerate a serious fine-tuning of the initial condition of the Yukawa coupling. Moreover, if the MDM particle mass could be relaxed to $\\sim10^8$ GeV, which would need some nonthermal production mechanisms to give a correct relic abundance, the Landau pole scale could be pushed up above the Planck scale.
Inelastic Scattering Form Factors
Energy Science and Technology Software Center (ESTSC)
1992-01-01
ATHENA-IV computes form factors for inelastic scattering calculations, using single-particle wave functions that are eigenstates of motion in either a Woods-Saxon potential well or a harmonic oscillator well. Two-body forces of Gauss, Coulomb, Yukawa, and a sum of cut-off Yukawa radial dependences are available.
Nonlinear interaction of compressional waves in a 2D dusty plasma crystal
Goree, John
52242 (May 30, 2003) Abstract Nonlinear mixing and harmonic generation of compressional waves were stud only above an excitation-power threshold due to frictional damping, as predicted by theory. PACS number a screened Coulomb repulsion or Yukawa potential. Sound waves, or phonons, in a 2D Yukawa lattice are well
Cleland, A.N.
1991-04-01
Experiments investigating the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very small capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters; the tunneling rate in the moderately damped (Q {approx} 1) junction is seen to be reduced by a factor of 300 from that predicted for an undamped junction. The phase is seen to be a good quantum-mechanical variable. The experiments on small capacitance tunnel junctions extend the measurements on the larger-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wavefunction has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias. I present the first clear observation of the Coulomb blockade in single junctions. The electrical environment of the tunnel junction, however, strongly affects the behavior of the junction: higher resistance leads are observed to greatly sharpen the Coulomb blockade over that seen with lower resistance leads. I present theoretical descriptions of how the environment influences the junctions; comparisons with the experimental results are in reasonable agreement.
Canfora, Fabrizio; Giacomini, Alex; Oliva, Julio
2010-08-15
It is shown that on curved backgrounds, the Coulomb gauge Faddeev-Popov operator can have zero modes even in the Abelian case. These zero modes cannot be eliminated by restricting the path integral over a certain region in the space of gauge potentials. The conditions for the existence of these zero modes are studied for static spherically symmetric spacetimes in arbitrary dimensions. For this class of metrics, the general analytic expression of the metric components in terms of the zero modes is constructed. Such expression allows one to find the asymptotic behavior of background metrics, which induce zero modes in the Coulomb gauge, an interesting example being the three-dimensional anti-de Sitter spacetime. Some of the implications for quantum field theory on curved spacetimes are discussed.
Elastic Scattering and Reaction Cross Section of the 6He+27Al System Close to the Coulomb Barrier
Lepine-Szily, A.; Benjamim, E. A.; Lichtenthaeler, R.; Guimaraes, V.; Chamon, L. C.; Hussein, M. S.; Alcantara Nunez, J.; Assuncao, M.; Barioni, A.; Camargo, O. Jr.; Denke, R. Z.; Faria, P. N. de; Mendes Junior, D. R.; Pires, K. C. C.; Gomes, P. R. S.; Arazi, A.; Padron, I.
2006-08-14
The RIBRAS (Radioactive Ion Beams Brazil) facility recently installed at the Pelletron Laboratory of the University of Sao Paulo consists of two superconducting solenoids used to produce and focalize beams of light radioactive nuclei, as 6He, 7Be,8Li etc. The low energy, light, radioactive beams available are used to study reactions close to the Coulomb barrier. The elastic scattering of the radioactive halo nucleus 6He on 27Al target was measured at four energies close to the Coulomb barrier. Reaction cross sections were extracted from the optical model fits, using the Sao Paulo Potential (SPP). The reduced reaction cross sections of 6He on 27Al were compared to reduced reaction cross sections for other projectiles as 6,7Li, 9Be and 16O on 27Al and they are larger than those for stable projectiles by an amount similar to the calculated nuclear break-up cross section for this system.
Control of the conformations of ion Coulomb crystals in a Penning trap
Mavadia, Sandeep; Goodwin, Joseph F.; Stutter, Graham; Bharadia, Shailen; Crick, Daniel R.; Segal, Daniel M.; Thompson, Richard C.
2013-01-01
Laser-cooled atomic ions form ordered structures in radiofrequency ion traps and in Penning traps. Here we demonstrate in a Penning trap the creation and manipulation of a wide variety of ion Coulomb crystals formed from small numbers of ions. The configuration can be changed from a linear string, through intermediate geometries, to a planar structure. The transition from a linear string to a zigzag geometry is observed for the first time in a Penning trap. The conformations of the crystals are set by the applied trap potential and the laser parameters, and agree with simulations. These simulations indicate that the rotation frequency of a small crystal is mainly determined by the laser parameters, independent of the number of ions and the axial confinement strength. This system has potential applications for quantum simulation, quantum information processing and tests of fundamental physics models from quantum field theory to cosmology. PMID:24096901
Time-dependent analysis of the nuclear and Coulomb dissociation of 11Be
Capel, Pierre; Goldstein, Gerald; Baye, Daniel
2005-10-14
The breakup of 11Be on carbon and lead targets around 70 MeV/nucleon is investigated within a semiclassical framework. The role of the (5/2){sup +} resonance is analyzed in both cases. It induces a narrow peak in the nuclear-induced breakup cross section, while its effect on Coulomb breakup is small. The nuclear interactions between the projectile and the target is responsible for the transition toward this resonant state. The influence of the parametrization of the 10Be-n potential that simulates 11Be is also addressed. The breakup calculation is found to be dependent on the potential choice. This leads us to question the reliability of this technique to extract spectroscopic factors.
Control of the conformations of ion Coulomb crystals in a Penning trap.
Mavadia, Sandeep; Goodwin, Joseph F; Stutter, Graham; Bharadia, Shailen; Crick, Daniel R; Segal, Daniel M; Thompson, Richard C
2013-01-01
Laser-cooled atomic ions form ordered structures in radiofrequency ion traps and in Penning traps. Here we demonstrate in a Penning trap the creation and manipulation of a wide variety of ion Coulomb crystals formed from small numbers of ions. The configuration can be changed from a linear string, through intermediate geometries, to a planar structure. The transition from a linear string to a zigzag geometry is observed for the first time in a Penning trap. The conformations of the crystals are set by the applied trap potential and the laser parameters, and agree with simulations. These simulations indicate that the rotation frequency of a small crystal is mainly determined by the laser parameters, independent of the number of ions and the axial confinement strength. This system has potential applications for quantum simulation, quantum information processing and tests of fundamental physics models from quantum field theory to cosmology. PMID:24096901
Testing the critical Coulomb wedge theory on hyper-extended rifted margins
NASA Astrophysics Data System (ADS)
Nirrengarten, Michael; Manatschal, Gianreto; Kusznir, Nick
2015-04-01
Deformation of hyper-extended continental crust and its relationship with the underlying mantle is a key process in the evolution of rifted margins. Recent studies have focused on hyper-extension in rifted margins using different approaches such as numerical modelling, seismic interpretation, potential field methods and field observations. However many fundamental questions about the observed structures and their evolution during the formation of hyper-extended margins are still debated. In this study an observation driven approach has been used to characterise geometrical and physical attributes of the continental crust termination, considered as a hyper-extended wedge, in order to test the applicability of critical Coulomb wedge theory to hyper-extended margins. The Coulomb wedge theory was first developed on accretionary prisms and on fold and thrust belts, but it has also been applied in extensional settings. Coulomb wedge theory explains the evolution of the critical aperture angle of the wedge as a function of basal sliding without deformation in the overlying wedge. This critical angle depends on the frictional parameters of the material, the basal friction, the surface slope, the basal dip and the fluid pressure. If the evolution of hyper-extended wedges could be described by the critical Coulomb wedge theory, it would have a major impact in the understanding of the structural and physical evolution of rifted domains during the hyper-extension processes. On seismic reflection lines imaging magma-poor hyper-extended margins, the continental crust termination is often shown to form a hyper-extended wedge. ODP Sites 1067, 900 and 1068 on the Iberian margin as well as field observations in the Alps give direct access to the rocks forming the hyper-extended wedge, which are typically composed of highly deformed and hydrated continental rocks underlain by serpentinised mantle. The boundary between the hydrated continental and mantle rocks corresponds to a decollement level. In order to test the critical Coulomb wedge theory on hyper-extended magma-poor rifted margins, we have analysed a number of high quality seismic sections from present-day margins (e.g Iberia, Newfoundland, Porcupine, Angola, Brazil, South China Sea). We have measured, in the brittle hyper-extended crust, the wedge angles (?) of the top-basement surface and the basal dip angle (?) of the crust-mantle interface. Preliminary results from this analysis show that the hyper-extended wedge aperture angle (?+?) ranges between 4° and 18°. Most hyper-extended wedges on the footwall of the detachment (lower plate margin) present aperture angles around 10-11° whereas aperture angles in the hanging-wall are more scattered. This observed difference may be linked to the direction of the basal shear in the conjugate wedges. While the applicability to hyper-extended rifted margins of critical Coulomb wedge physics has to be numerically tested, initial results suggest a promising new approach to investigate the hyper-extension processes.
Ion wake effects on the Coulomb ion drag in complex dusty plasmas
Ki, Dae-Han; Jung, Young-Dae
2010-09-06
The ion wake effects on the Coulomb drag force are investigated in complex dusty plasmas. It is shown that the ion wake effects significantly enhance the Coulomb ion drag force. It is also found that the ion wake effects on the Coulomb drag force increase with an increase in the Debye length. In addition, the ion wake effects on the momentum transfer cross section and Coulomb drag force are found to be increased with increasing thermal Mach number, i.e., decreasing plasma temperature. It is also found that the Coulomb ion drag force would be stronger for smaller dust grains.
Aftershock triggering by postseismic stresses: A study based on Coulomb rate-and-state models
NASA Astrophysics Data System (ADS)
Cattania, Camilla; Hainzl, Sebastian; Wang, Lifeng; Enescu, Bogdan; Roth, Frank
2015-04-01
The spatiotemporal clustering of earthquakes is a feature of medium- and short-term seismicity, indicating that earthquakes interact. However, controversy exists about the physical mechanism behind aftershock triggering: static stress transfer and reloading by postseismic processes have been proposed as explanations. In this work, we use a Coulomb rate-and-state model to study the role of coseismic and postseismic stress changes on aftershocks and focus on two processes: creep on the main shock fault plane (afterslip) and secondary aftershock triggering by previous aftershocks. We model the seismic response to Coulomb stress changes using the Dieterich constitutive law and focus on two events: the Parkfield, Mw = 6.0, and the Tohoku, Mw = 9.0, earthquakes. We find that modeling secondary triggering systematically improves the maximum log likelihood fit of the sequences. The effect of afterslip is more subtle and difficult to assess for near-fault events, where model errors are largest. More robust conclusions can be drawn for off-fault aftershocks: following the Tohoku earthquake, afterslip promotes shallow crustal seismicity in the Fukushima region. Simple geometrical considerations indicate that afterslip-induced stress changes may have been significant on trench parallel crustal fault systems following several of the largest recorded subduction earthquakes. Moreover, the time dependence of afterslip strongly enhances its triggering potential: seismicity triggered by an instantaneous stress change decays more quickly than seismicity triggered by gradual loading, and as a result we find afterslip to be particularly important between few weeks and few months after the main shock.
John Bulava; Philip Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy
2011-11-11
We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the phase transition temperature are presented. In general, this model may be relevant for BSM scenarios with a heavy fourth generation of quarks.
Goree, John
Shear Flows and Shear Viscosity in a Two-Dimensional Yukawa System (Dusty Plasma) V. Nosenko* and J 21 May 2004; published 7 October 2004) The shear viscosity of a two-dimensional liquid-state dusty. By fitting the particle velocity profiles in the shear flow to a Navier-Stokes model, the kinematic viscosity
Volker Bach; Sébastien Breteaux; Sören Petrat; Peter Pickl; Tim Tzaneteas
2015-03-03
We study the time evolution of a system of $N$ spinless fermions in $\\mathbb{R}^3$ which interact through a pair potential, e.g., the Coulomb potential. We compare the dynamics given by the solution to Schr{\\"o}dinger's equation with the time-dependent Hartree-Fock approximation, and we give an estimate for the accuracy of this approximation in terms of the kinetic energy of the system. This leads, in turn, to bounds in terms of the initial total energy of the system.
Electronic cooling via interlayer Coulomb coupling in multilayer epitaxial graphene
NASA Astrophysics Data System (ADS)
Mihnev, Momchil T.; Tolsma, John R.; Divin, Charles J.; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A.; MacDonald, Allan H.; Norris, Theodore B.
2015-09-01
In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron-phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport, even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier dynamics as temperature and the number of layers is varied.
Glassy Dynamics in Geometrically Frustrated Coulomb Liquids without Disorder
NASA Astrophysics Data System (ADS)
Mahmoudian, Samiyeh; Rademaker, Louk; Ralko, Arnaud; Fratini, Simone; Dobrosavljevi?, Vladimir
2015-07-01
We show that introducing long-range Coulomb interactions immediately lifts the massive ground state degeneracy induced by geometric frustration for electrons on quarter-filled triangular lattices in the classical limit. Important consequences include the stabilization of a stripe-ordered crystalline (global) ground state, but also the emergence of very many low-lying metastable states with amorphous "stripe-glass" spatial structures. Melting of the stripe order thus leads to a frustrated Coulomb liquid at intermediate temperatures, showing remarkably slow (viscous) dynamics, with very long relaxation times growing in Arrhenius fashion upon cooling, as typical of strong glass formers. On shorter time scales, the system falls out of equilibrium and displays the aging phenomena characteristic of supercooled liquids above the glass transition. Our results show remarkable similarity with the recent observations of charge-glass behavior in ultraclean triangular organic materials of the ? -(BEDT -TTF )2 family.
Intermolecular Coulomb Decay at Weakly Coupled Heterogeneous Interfaces
NASA Astrophysics Data System (ADS)
Grieves, Gregory A.; Orlando, Thomas M.
2011-07-01
Surface ejection of H+(H2O)n=1-8 from low energy electron irradiated water clusters adsorbed on graphite and graphite with overlayers of Ar, Kr or Xe results from intermolecular Coulomb decay (ICD) at the mixed interface. Inner valence holes in water (2a1-1), Ar (3s-1), Kr (4s-1), and Xe (5s-1) correlate with the cluster appearance thresholds and initiate ICD. Proton transfer occurs during or immediately after ICD and the resultant Coulomb explosion leads to H+(H2O)n=1-8 desorption with kinetic energies that vary with initiating state, final state, and interatomic or molecular distances.
Characterization of ion Coulomb crystals for fundamental sciences
NASA Astrophysics Data System (ADS)
Okada, Kunihiro; Ichikawa, Masanari; Wada, Michiharu
2015-05-01
We performed classical molecular dynamics (MD) simulations in order to search the conditions for efficient sympathetic cooling of highly charged ions (HCIs) in a linear Paul trap. Small two-component ion Coulomb crystals consisting of laser-cooled ions and HCIs were characterized by the results of the MD simulations. We found that the spatial distribution is determined by not only the charge-to-mass ratio but also the space charge effect. Moreover, the simulation results suggest that the temperature of HCIs do not necessarily decrease with increasing the number of laser-cooled ions in the cases of linear ion crystals. We also determined the cooling limit of sympathetically cooled 165Ho14+ ions in small linear ion Coulomb crystals. The present results show that sub-milli-Kelvin temperatures of at least 10 Ho14+ ions will be achieved by sympathetic cooling with a single laser-cooled Be+.
Coulomb effects in low-energy nuclear fragmentation
NASA Technical Reports Server (NTRS)
Wilson, John W.; Chun, Sang Y.; Badavi, Francis F.; John, Sarah
1993-01-01
Early versions of the Langley nuclear fragmentation code NUCFRAG (and a publicly released version called HZEFRG1) assumed straight-line trajectories throughout the interaction. As a consequence, NUCFRAG and HZEFRG1 give unrealistic cross sections for large mass removal from the projectile and target at low energies. A correction for the distortion of the trajectory by the nuclear Coulomb fields is used to derive fragmentation cross sections. A simple energy-loss term is applied to estimate the energy downshifts that greatly alter the Coulomb trajectory at low energy. The results, which are far more realistic than prior versions of the code, should provide the data base for future transport calculations. The systematic behavior of charge-removal cross sections compares favorably with results from low-energy experiments.
Cooling of cryogenic electron bilayers via the Coulomb interaction
John King Gamble; Mark Friesen; Robert Joynt; S. N. Coppersmith
2011-04-13
Heat dissipation in current-carrying cryogenic nanostructures is problematic because the phonon density of states decreases strongly as energy decreases. We show that the Coulomb interaction can prove a valuable resource for carrier cooling via coupling to a nearby, cold electron reservoir. Specifically, we consider the geometry of an electron bilayer in a silicon-based heterostructure, and analyze the power transfer. We show that across a range of temperatures, separations, and sheet densities, the electron-electron interaction dominates the phonon heat-dissipation modes as the main cooling mechanism. Coulomb cooling is most effective at low densities, when phonon cooling is least effective in silicon, making it especially relevant for experiments attempting to perform coherent manipulations of single spins.
Silicon-based Coulomb blockade thermometer with Schottky barriers
NASA Astrophysics Data System (ADS)
Tuboltsev, V.; Savin, A.; Rogozin, V. D.; Räisänen, J.
2014-04-01
A hybrid Coulomb blockade thermometer (CBT) in form of an array of intermittent aluminum and silicon islands connected in series via tunnel junctions was fabricated on a thin silicon-on-insulator (SOI) film. Tunnel barriers in the micrometer size junctions were formed by metal-semiconductor Schottky contacts between aluminium electrodes and heavily doped silicon. Differential conductance through the array vs. bias voltage was found to exhibit characteristic features of competing thermal and charging effects enabling absolute temperature measurements over the range of ˜65 to ˜500 mK. The CBT performance implying the primary nature of the thermometer demonstrated for rather trivial architecture attempted in this work paves a route for introduction of Coulomb blockade thermometry into well-developed contemporary SOI technology.
Orbital ice: An exact Coulomb phase on the diamond lattice
Chern Giawei; Wu Congjun
2011-12-15
We demonstrate the existence of an orbital Coulomb phase as the exact ground state of a p-orbital exchange Hamiltonian on the diamond lattice. The Coulomb phase is an emergent state characterized by algebraic dipolar correlations and a gauge structure resulting from local constraints (ice rules) of the underlying lattice models. For most ice models on the pyrochlore lattice, these local constraints are a direct consequence of minimizing the energy of each individual tetrahedron. On the contrary, the orbital ice rules are emergent phenomena resulting from the quantum orbital dynamics. We show that the orbital ice model exhibits an emergent geometrical frustration by mapping the degenerate quantum orbital ground states to the spin-ice states obeying the 2-in-2-out constraints on the pyrochlore lattice. We also discuss possible realization of the orbital ice model in optical lattices with p-band fermionic cold atoms.
Electronic cooling via interlayer Coulomb coupling in multilayer epitaxial graphene
Mihnev, Momchil T.; Tolsma, John R.; Divin, Charles J.; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A.; MacDonald, Allan H.; Norris, Theodore B.
2015-01-01
In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron–phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport, even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier dynamics as temperature and the number of layers is varied. PMID:26399955
Structural phase transitions and topological defects in ion Coulomb crystals
Partner, Heather L.; Nigmatullin, Ramil; Burgermeister, Tobias; Keller, Jonas; Pyka, Karsten; Plenio, Martin B.; Retzker, Alex; Zurek, Wojciech Hubert; del Campo, Adolfo; Mehlstaubler, Tanja E.
2014-11-19
We use laser-cooled ion Coulomb crystals in the well-controlled environment of a harmonic radiofrequency ion trap to investigate phase transitions and defect formation. Topological defects in ion Coulomb crystals (kinks) have been recently proposed for studies of nonlinear physics with solitons and as carriers of quantum information. Defects form when a symmetry breaking phase transition is crossed non-adiabatically. For a second order phase transition, the Kibble-Zurek mechanism predicts that the formation of these defects follows a power law scaling in the rate of the transition. We demonstrate a scaling of defect density and describe kink dynamics and stability. We further discuss the implementation of mass defects and electric fields as first steps toward controlled kink preparation and manipulation.
Electronic Cooling via Interlayer Coulomb Coupling in Multilayer Epitaxial Graphene
Mihnev, Momchil T; Divin, Charles J; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A; MacDonald, Allan H; Norris, Theodore B
2015-01-01
In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron-phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier ...
Coulomb excitation of the 242mAm isomer
Hayes, A; Cline, D; Moody, K; Wu, C; Becker, J; Carpenter, M; Carroll, J; Gohlke, D; Greene, J; Hecht, A; Janssens, R; Karamian, S; Lauritsen, T; Lister, C; Macri, R; Propri, R; Seweryniak, D; Wang, X; Wheeler, R; Zhu, S
2006-10-24
The {sup 242m}Am isomer, a well-known candidate for photo-depopulation research, has been studied in this first ever Coulomb excitation of a nearly pure ({approx} 98%) isomer target. Thirty new states, including a new rotational band built on a K{sup {pi}} = 6{sup -} state have been identified. Strong K-mixing results in nearly equal populations of the K{sup {pi}} = 5{sup -} and 6{sup -} states. Newly identified states have been assigned to the K{sup {pi}} = 3{sup -} rotational band, the lowest states of which are known to decay into the ground-state band. Implications regarding K-mixing and Coulomb excitation paths to the ground state are discussed.
Elastic scattering of Beryllium isotopes near the Coulomb barrier
Di Pietro, A.; Figuera, P.; Amorini, F.; Fisichella, M.; Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Randisi, G.; Rizzo, F.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.; Torresi, D.; Papa, M.; Acosta, L.; Martel, I.; Perez-Bernal, F.; Borge, M. J. G.; Tengblad, O.
2011-10-28
In this contribution, results of experiments performed with the three Beryllium isotopes {sup 9,10,11}Be on a medium mass {sup 64}Zn target, at a center of mass energy of {approx_equal}1.4 the Coulomb barrier, will be discussed. Elastic scattering angular distributions have been measured for the {sup 9,10}Be reactions. In the {sup 11}Be case the quasielastic scattering angular distribution was obtained. In the halo nucleus case, the angular distribution exhibit a non-Fresnel-type pattern with a strong damping of the Coulomb-nuclear interference peak. Moreover, it is found that the total reaction cross-section for the halo nucleus induced collision is more than double the ones extracted in the collisions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the {sup 11}Be case could be attributed to transfer and/or break-up events.
Phase diagram of the Kane-Mele-Coulomb model
Hohenadler, M; Herbut, I F; Assaad, F F
2014-01-01
We determine the phase diagram of the Kane-Mele model with a long-range Coulomb interaction using an exact quantum Monte Carlo method. Long-range interactions are expected to play a role in honeycomb materials because the vanishing density of states in the semimetallic weak-coupling phase suppresses screening. According to our results, the Kane-Mele-Coulomb model supports the same phases as the Kane-Mele-Hubbard model. The nonlocal part of the interaction promotes short-range sublattice charge fluctuations, which compete with antiferromagnetic order driven by the onsite repulsion. Consequently, the critical interaction for the magnetic transition is significantly larger than for the purely local Hubbard repulsion. Our numerical data are consistent with $SU(2)$ Gross-Neveu universality for the semimetal to antiferromagnet transition, and with 3D XY universality for the quantum spin Hall to antiferromagnet transition.
Phase diagram of the Kane-Mele-Coulomb model
NASA Astrophysics Data System (ADS)
Hohenadler, M.; Parisen Toldin, F.; Herbut, I. F.; Assaad, F. F.
2014-08-01
We determine the phase diagram of the Kane-Mele model with a long-range Coulomb interaction using an exact quantum Monte Carlo method. Long-range interactions are expected to play a role in honeycomb materials because the vanishing density of states in the semimetallic weak-coupling phase suppresses screening. According to our results, the Kane-Mele-Coulomb model supports the same phases as the Kane-Mele-Hubbard model. The nonlocal part of the interaction promotes short-range sublattice charge fluctuations, which compete with antiferromagnetic order driven by the onsite repulsion. Consequently, the critical interaction for the magnetic transition is significantly larger than for the purely local Hubbard repulsion. Our numerical data are consistent with SU (2) Gross-Neveu universality for the semimetal to antiferromagnet transition, and with 3D XY universality for the quantum spin Hall to antiferromagnet transition.
Phase diagram of the Kane-Mele-Coulomb model
M. Hohenadler; F. Parisen Toldin; I. F. Herbut; F. F. Assaad
2014-08-29
We determine the phase diagram of the Kane-Mele model with a long-range Coulomb interaction using an exact quantum Monte Carlo method. Long-range interactions are expected to play a role in honeycomb materials because the vanishing density of states in the semimetallic weak-coupling phase suppresses screening. According to our results, the Kane-Mele-Coulomb model supports the same phases as the Kane-Mele-Hubbard model. The nonlocal part of the interaction promotes short-range sublattice charge fluctuations, which compete with antiferromagnetic order driven by the onsite repulsion. Consequently, the critical interaction for the magnetic transition is significantly larger than for the purely local Hubbard repulsion. Our numerical data are consistent with $SU(2)$ Gross-Neveu universality for the semimetal to antiferromagnet transition, and with 3D XY universality for the quantum spin Hall to antiferromagnet transition.
Coulomb excitation of $^{68}$Ni at safe energies
N. Bree; I. Stefanescu; P. A. Butler; J. Cederkäll; T. Davinson; P. Delahaye; J. Eberth; D. Fedorov; V. N. Fedosseev; L. M. Fraile; S. Franchoo; G. Georgiev; K. Gladnishki; M. Huyse; O. Ivanov; J. Iwanicki; J. Jolie; U. Köster; Th. Kröll; R. Krücken; B. A. Marsh; O. Niedermaier; P. Reiter; H. Scheit; D. Schwalm; T. Sieber; J. Van de Walle; P. Van Duppen; N. Warr; D. Weisshaar; F. Wenander; S. Zemlyanoy
2008-11-19
The $B(E2;0^+\\to2^+)$ value in $^{68}$Ni has been measured using Coulomb excitation at safe energies. The $^{68}$Ni radioactive beam was post-accelerated at the ISOLDE facility (CERN) to 2.9 MeV/u. The emitted $\\gamma$ rays were detected by the MINIBALL detector array. A kinematic particle reconstruction was performed in order to increase the measured c.m. angular range of the excitation cross section. The obtained value of 2.8$^{+1.2}_{-1.0}$ 10$^2$ e$^2$fm$^4$ is in good agreement with the value measured at intermediate energy Coulomb excitation, confirming the low $0^+\\to2^+$ transition probability.
Quark-Monopole Potentials from Supersymmetric SL(3,R) Deformed IIB Supergravity
Changhyun Ahn
2006-08-22
We recompute the quark-monopole potential from supersymmetric SL(3,R) deformation of IIB supergravity background dual to deformed Coulomb branch flow of the N=4 super Yang-Mills theory. The marginal deformations strengthen the Coulombic attraction between quarks and monopoles.
Coulomb excitations for a short linear chain of metallic shells
Zhemchuzhna, Liubov; Gumbs, Godfrey; Iurov, Andrii; Huang, Danhong; Gao, Bo
2015-03-15
A self-consistent-field theory is given for the electronic collective modes of a chain containing a finite number, N, of Coulomb-coupled spherical two-dimensional electron gases arranged with their centers along a straight line, for simulating electromagnetic response of a narrow-ribbon of metallic shells. The separation between nearest-neighbor shells is arbitrary and because of the quantization of the electron energy levels due to their confinement to the spherical surface, all angular momenta L of the Coulomb excitations, as well as their projections M on the quantization axis, are coupled. However, for incoming light with a given polarization, only one angular momentum quantum number is usually required. Therefore, the electromagnetic response of the narrow-ribbon of metallic shells is expected to be controlled externally by selecting different polarizations for incident light. We show that, when N?=?3, the next-nearest-neighbor Coulomb coupling is larger than its value if they are located at opposite ends of a right-angle triangle forming the triad. Additionally, the frequencies of the plasma excitations are found to depend on the orientation of the line joining them with respect to the axis of quantization since the magnetic field generated from the induced oscillating electric dipole moment on one sphere can couple to the induced magnetic dipole moment on another. Although the transverse inter-shell electromagnetic coupling can be modeled by an effective dynamic medium, the longitudinal inter-shell Coulomb coupling, on the other hand, can still significantly modify the electromagnetic property of this effective medium between shells.
Cavity EIT with ion Coulomb crystals Michael Drewsen
Hensinger, Winfried
crystals #12;cav=atom 1,1 ,..., ,1totNg g g For multi-particle states: 2 1 1 totN i ic = = tot Why Coulomb crystals ? Interaction with a single photon 1 2 1 ,0 , ,..., ,..., ,0 , tot tot N i i N i e c g g e g = 1 2 1 1 ,0 , ,..., ,..., ,0 tot tot N i N itot e g g e g N = Ideally: Actually: Effective number
Stability characterizations of fixtured rigid bodies with Coulomb friction
PANG,J.S.; TRINKLE,JEFFREY C.
2000-02-15
This paper formally introduces several stability characterizations of fixtured three-dimensional rigid bodies initially at rest and in unilateral contact with Coulomb friction. These characterizations, weak stability and strong stability, arise naturally from the dynamic model of the system, formulated as a complementarity problem. Using the tools of complementarity theory, these characterizations are studied in detail to understand their properties and to develop techniques to identify the stability classifications of general systems subjected to known external loads.
Coulomb field scattering in Born-Infeld electrodynamics
Tennant, Daniel
2011-02-15
In the context of Born-Infeld electrodynamics, the electromagnetic fields interact with each other via their nonlinear couplings. A calculation will be performed where an incoming electromagnetic plane wave scatters off a Coulomb field in the geometrical optics approximation. In addition to finding the first-order angle of deflection, exact solutions for the trajectory will also be found. The possibility of electromagnetic bound states will be discussed.
Molecular Dynamics Simulation of Shear Moduli for Coulomb Crystals
C. J. Horowitz; J. Hughto
2008-12-15
Torsional (shear) oscillations of neutron stars may have been observed in quasiperiodic oscillations of Magnetar Giant Flares. The frequencies of these modes depend on the shear modulus of neutron star crust. We calculate the shear modulus of Coulomb crystals from molecular dynamics simulations. We find that electron screening reduces the shear modulus by about 10% compared to previous Ogata et al. results. Our MD simulations can be extended to calculate the effects of impurities and or polycrystalline structures on the shear modulus.
Coulomb-Gauge Gluon Propagator and the Gribov Formula
Burgio, G.; Quandt, M.; Reinhardt, H.
2009-01-23
We analyze the lattice SU(2) Yang-Mills theory in the Coulomb gauge. We show that the static gluon propagator is multiplicative renormalizable and takes the simple form D(|p-vector|){sup -1}={radical}(|p-vector|{sup 2}+M{sup 4}/|p-vector|{sup 2}), proposed by Gribov through heuristic arguments many years ago. We find M=0.88(1) GeV{approx_equal}2{radical}({sigma})
The relativistic Dirac-Coulomb-Fock effect on atomization energies.
Kedziora, G. S.; Pople, J. A.; Rassolov, V.; Ratner, M.; Redfern, P. C.; Curtiss, L. A.; Chemistry; Northwestern Univ.
1999-04-01
We have used a second-order perturbation treatment of the Dirac-Coulomb-Hartree-Fock method to estimate relativistic contributions to energies in the G2/97 test set. The one-electron relativistic effect on atomization energies of molecules containing first- and second-row atoms nearly always reduces binding. When the relativistic corrections are included in G3 theory and assessed on the G2/97 test set, there is little change in overall performance.
Yukawa coupling beta-functions in the Standard Model at three loops
NASA Astrophysics Data System (ADS)
Bednyakov, A. V.; Pikelner, A. F.; Velizhanin, V. N.
2013-05-01
We present the results for three-loop beta-functions for Yukawa couplings of heavy Standard Model fermions calculated within the unbroken phase of the model. The calculation is carried out with the help of the MINCER program in a general linear gauge, and the final result is independent of the gauge-fixing parameters. In order to calculate three-point functions, we made use of infrared rearrangement (IRR) trick. Due to the chiral structure of the SM a careful treatment of loops with fermions is required to perform the calculation. It turns out that gauge anomaly cancellation in the SM allows us to obtain the result by means of the semi-naive treatment of ?5.
Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector
Aad, G.
2015-04-21
Results of a search for H ? ?? decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb–1 and 20.3 fb–1 at centre-of-mass energies of ?s=7 TeV and ?s=8 TeV respectively. All combinations of leptonic (? ? ???¯ with ? = e, ?) and hadronic (? ? hadrons ?) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standardmore »deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalized to the Standard Model expectation, of ? = 1.43–0.37+0.43 is consistent with the predicted Yukawa coupling strength in the Standard Model.« less
A Dream of Yukawa — Non-Local Fields out of Non-Commutative Spacetime —
NASA Astrophysics Data System (ADS)
Naka, Shigefumi; Toyoda, Haruki; Takanashi, Takahiro; Umezawa, Eizo
The coordinates of ?-Minkowski spacetime form Lie algebraic elements, in which time and space coordinates do not commute in spite of that space coordinates commute each other. The non-commutativity is realized by a Planck-length-scale constant ? - 1( ne 0), which is a universal constant other than the light velocity under the ?-Poincare transformation. Such a non-commutative structure can be realized by SO(1,4) generators in dS4 spacetime. In this work, we try to construct a ?-Minkowski like spacetime with commutative 4-dimensional spacetime based on Adsn+1 spacetime. Another aim of this work is to study invariant wave equations in this spacetime from the viewpoint of non-local field theory by H. Yukawa, who expected to realize elementary particle theories without divergence according to this viewpoint.
Radiatively induced flavour violation in the general two-Higgs doublet model with Yukawa alignment
Carolin B. Braeuninger; Alejandro Ibarra; Cristoforo Simonetto
2010-06-15
The most general two Higgs doublet model contains new sources of flavour violation that are usually in conflict with the experimental constraints. One possibility to suppress the exotic contribution to the flavour changing neutral currents consists on imposing the alignment of the Yukawa couplings. This condition presumably holds at a high-energy scale and is spoiled by the radiative corrections. We compute in this letter the size of the radiatively induced flavour violating Higgs couplings at the electroweak scale. These also yield the absolute lower bound on the size of the exotic contributions to the flavour changing neutral currents in any two Higgs doublet model, barring cancellations and the existence of discrete symmetries. We show that these contributions are well below the experimental bounds in large regions of the parameter space.
Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector
NASA Astrophysics Data System (ADS)
Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baas, A. E.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boddy, C. R.; Boehler, M.; Boek, T. T.; Bogaerts, J. A.; Bogdanchikov, A. G.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boutouil, S.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Brendlinger, K.; Brennan, A. J.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, J.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Bryngemark, L.; Buanes, T.; Buat, Q.; Bucci, F.; Buchholz, P.
2015-04-01
Results of a search for H ? ?? decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb-1 and 20.3 fb-1 at centre-of-mass energies of TeV and TeV respectively. All combinations of leptonic ( with ? = e, ?) and hadronic ( ? ? hadrons ?) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of ? = 1. 43{-/0.37 + 0.43} is consistent with the predicted Yukawa coupling strength in the Standard Model. [Figure not available: see fulltext.
Hexatic phase in two-dimensional Yukawa systems: Existence and properties
NASA Astrophysics Data System (ADS)
Koss, X. G.; Vaulina, O. S.
2015-11-01
In present work, phase transitions in strongly-coupled two-dimensional dissipative Yukawa systems are studied. The thermodynamic characteristics of these systems are calculated, namely the internal energy, the specific heat and the entropy. The considered characteristics have two singular points; one of these points corresponds to the first-order phase transition from crystal to the hexatic phase, and another point corresponds to the second-order phase transition from the hexatic phase to the isotropic liquid. The dependence of the position of the melting lines and the range of existence of the hexatic phase on the concentration of the grains in the considered system is studied. The special attention is paid to the comparison of our results to the existing numerical and analytical data.
Two-Yukawa fluid at a hard wall: Field theory treatment
Kravtsiv, I.; Patsahan, T.; Holovko, M.; Caprio, D. di
2015-05-21
We apply a field-theoretical approach to study the structure and thermodynamics of a two-Yukawa fluid confined by a hard wall. We derive mean field equations allowing for numerical evaluation of the density profile which is compared to analytical estimations. Beyond the mean field approximation, analytical expressions for the free energy, the pressure, and the correlation function are derived. Subsequently, contributions to the density profile and the adsorption coefficient due to Gaussian fluctuations are found. Both the mean field and the fluctuation terms of the density profile are shown to satisfy the contact theorem. We further use the contact theorem to improve the Gaussian approximation for the density profile based on a better approximation for the bulk pressure. The results obtained are compared to computer simulation data.
Proton Decay, Yukawa Couplings and Underlying Gauge Symmetry in String Theory
Radu Tatar; Taizan Watari
2006-03-20
In string theory, massless particles often originate from a symmetry breaking of a large gauge symmetry G to its subgroup H. The absence of dimension-4 proton decay in supersymmetric theories suggests that (\\bar{D},L) are different from \\bar{H}(\\bar{\\bf 5}) in their origins. In this article, we consider a possibility that they come from different irreducible components in $\\mathfrak{g}/\\mathfrak{h}$. Requiring that all the Yukawa coupling constants of quarks and leptons be generated from the super Yang--Mills interactions of G, we found in the context of Georgi--Glashow H=SU(5) unification that the minimal choice of G is E_7 and E_8 is the only alternative. This idea is systematically implemented in Heterotic String, M theory and F theory, confirming the absence of dimension 4 proton decay operators. Not only H=SU(5) but also G constrain operators of effective field theories, providing non-trivial information.
Mixed Axion/Axino Dark Matter in mSUGRA and Yukawa-unified SUSY
Ann Summy, Heaya
2010-02-10
Axion/axino dark matter (DM) is explored in the minimal supergravity (mSUGRA) and Yukawa-unified supersymmetric grand-unified theory (SUSY GUT) models with surprising results. For this type of scenario, relic DM abundance has three components: i.) cold axions, ii.) warm axinos from neutralino decay, and iii.) cold or warm thermally produced axinos. Reheat temperatures T{sub R} exceeding 10{sup 6} GeV are required in order to solve the gravitino/Big Bang Nucleosynthesis (BBN) problem while also allowing for baryogensis via non-thermal leptogenesis. In order to attain high enough reheat temperatures, we also need high values of the Peccei-Quinn (PQ) breaking scale f{sub a} on the order 10{sup 11}-10{sup 12} GeV.
A variational calculation of particle-antiparticle bound states in the scalar Yukawa model
Bingfeng Ding; Jurij Darewych
1999-08-05
We consider particle-antiparticle bound states in the scalar Yukawa (Wick-Cutkosky) model. The variational method in the Hamiltonian formalism of quantum field theory is employed. A reformulation of the model is studied, in which covariant Green's functions are used to solve for the mediating field in terms of the particle fields. A simple Fock-state variational ansatz is used to derive a relativistic equation for the particle-antiparticle states. This equation contains one-quantum-exchange and virtual-annihilation interactions. It is shown that analytic solutions of this equation can be obtained for the simplified case where only the virtual annihilation interaction is retained. More generally, numerical and perturbative solutions of the equation are obtained for the massive and massless-exchange cases. We compare our results with various Bethe-Salpeter-based calculations.
Alignment, reverse alignment, and wrong sign Yukawa couplings in two Higgs doublet models
Biswas, Ambalika
2015-01-01
We consider two Higgs doublet models with a softly broken U(1) symmetry, for various limiting values of the scalar mixing angles $\\alpha$ and $\\beta$. These correspond to the Standard Model Higgs particle being the lighter CP-even scalar (alignment) or the heavier CP-even scalar (reverse alignment), and also the limit in which some of the Yukawa couplings of this particle are of the opposite sign from the vector boson couplings (wrong sign). In these limits we impose a criterion for naturalness by demanding that quadratic divergences cancel at one loop. We plot the allowed masses of the remaining physical scalars based on naturalness, stability, perturbative unitarity and constraints coming from the $\\rho$ parameter.
The Effects of Ion Ion Coulomb Collisions on the Plasma Presheath.
NASA Astrophysics Data System (ADS)
Scheuer, Jay Thomas
The effects of ion-ion Coulomb collisions on the presheath region of an unmagnetized plasma are investigated using both kinetic and fluid treatments. In the kinetic treatment, ion collisions are included in the analysis through a Bhatnagar-Gross-Krook (BGK) collision term. An equation describing the electrostatic potential variation in the presheath region is derived and solved numerically for the range of collisionless to moderately collisional plasmas. Ion-ion Coulomb collisions are modeled by a form of the BGK collision operator which conserves particles, momentum and energy. The results obtained for moderate collisionality show that ion-ion collisions have little effect on the presheath. Ion-neutral charge exchange collisions are modeled by conserving only particles in a collision, since momentum and energy are transferred to the neutral species. In this case the presheath is affected by collisions and shows an increased potential drop. Ion-ion collisional effects are also investigated using fluid equations which are valid in collisionless and collisional limits. Effects of neutral gas-plasma interactions are included through the source terms in the fluid equations. The effects of ion-ion collisions are included through the closure conditions. The collisionless equations are solved numerically and the results compared to previous kinetic results. This comparison shows that the fluid equations are a reasonable approach to calculating presheath profiles. Results obtained from the collisional fluid equations show that ion-ion Coulomb collisions have a negligible effect on the plasma presheath. These results are in agreement with the results of the kinetic treatment. The effects of the choice of ion source function in a collisionless plasma are also discussed. Two difference ion source functions are examined. One source function, used by Emmert et al. (Phys. Fluids 23, 803 (1980)), results in an ion distribution function which is Maxwellian in a region of no potential gradients. Another source, used by Bissell and Johnson (Phys. Fluids 30, 779 (1987)), is assumed to be due to the ionization of a Maxwellian distribution of neutrals, and results in an ion distribution function which is peaked and markedly non-Maxwellian.
Colossal Coulomb Drag in Double Bilayer Graphene Heterostructures
NASA Astrophysics Data System (ADS)
Lee, Kayoung; Xue, Jaimin; Taniguchi, Takashi; Watanabe, Kenji; Tutuc, Emanuel
2015-03-01
Double-layer electron systems, where charge carriers are apart into two parallel layers, have been of interest thanks to their various interlayer interaction phenomena. One of the peculiar interaction features is Coulomb drag, in which current flowing in one layer (drive layer) induces voltage drop in the opposite layer (drag layer) via interlayer momentum transfer. Recent progress in the fabrication of heterostructures consisting of atomic layer materials such as graphene and hexagonal boron nitride (hBN) has led to high mobility double layer systems. Here we probe Coulomb drag in double bilayer graphene heterostructures separated by 2 - 5 nm thick hBN dielectrics. At temperatures (T) lower than 30 K, we observe an anomalous Coulomb drag in the vicinity of the drag layer charge neutrality points, which increases as T is reduced. At T = 1.4 K, the lowest temperature studied here, the drag resistivity becomes comparable to the layer resistivity at a finite drag layer density ndrag ~ 1 - 4 1011 cm-2. The ratio of the drag to layer resistivity increases as the hBN thickness reduces, and also as the drag layer mobility increases. At T >50K, we observe diffusive drag, which increases with T. We thank ONR, NRI and Intel for support.
Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule
Ian C. Cloët; Wolfgang Bentz; Anthony W. Thomas
2015-06-19
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 $\\left|\\mathbf{q}\\right| \\gtrsim 0.5\\,$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.
Optimal reconfigurations of two-craft Coulomb formations along manifolds
NASA Astrophysics Data System (ADS)
Jones, Drew R.; Schaub, Hanspeter
2013-02-01
Coulomb formations refer to swarms of closely flying spacecraft, in which the net electric charge of each vehicle is controlled. Active charge control is central to this concept and enables a propulsion system with highly desirable characteristics, albeit with limited controllability. Numerous Coulomb formation equilibria have been derived, but to maintain and maneuver these configurations, some inertial thrust is required to supplement the nearly propellant-less charge control. In this work, invariant manifold theory is applied to two-craft Coulomb equilibria, which are admitted in a linearized two-body gravity model. The manifolds associated with these systems are analyzed for the first time, and are then utilized as part of a general procedure for formulating optimal reconfigurations. Specifically, uncontrolled flows along the manifolds are sought which provide near continuous transfers from one equilibrium to another. Control is then introduced to match continuity, while minimizing inertial thrusting. This methodology aims to exploit uncontrolled motions and charge control to realize the shape-changing ability of these formations, without large inertial control efforts. Some variations in formulating and parameterizing the optimal transfers are discussed, and analytical expressions are derived to aid in establishing control parameter limits, under certain assumptions. Numerical results are provided, as demonstrative examples of the optimization procedure, using relatively simple control approximations. Finally, Particle Swarm Optimization, a novel stochastic method, is used with considerable success to solve the numerically difficult parameter optimization problems.
Dynamic study on fusion reactions for $^{40,48}$Ca+$^{90,96}$Zr around Coulomb barrier
Ning Wang; Xizhen Wu; Zhuxia Li
2003-01-09
By using the updated improved Quantum Molecular Dynamics model in which a surface-symmetry potential term has been introduced for the first time, the excitation functions for fusion reactions of $^{40,48}$Ca+$^{90,96}$Zr at energies around the Coulomb barrier have been studied. The experimental data of the fusion cross sections for $^{40}$Ca+$^{90,96}$Zr have been reproduced remarkably well without introducing any new parameters. The fusion cross sections for the neutron-rich fusion reactions of $^{48}$Ca+$^{90,96}$Zr around the Coulomb barrier are predicted to be enhanced compared with a non-neutron-rich fusion reaction. In order to clarify the mechanism of the enhancement of the fusion cross sections for neutron-rich nuclear fusions, we pay a great attention to study the dynamic lowering of the Coulomb barrier during a neck formation. The isospin effect on the barrier lowering is investigated. It is interesting that the effect of the projectile and target nuclear structure on fusion dynamics can be revealed to a certain extent in our approach. The time evolution of the N/Z ratio at the neck region has been firstly illustrated. A large enhancement of the N/Z ratio at neck region for neutron-rich nuclear fusion reactions is found.
Running Non-Minimal Inflation with Stabilized Inflaton Potential
Okada, Nobuchika
2015-01-01
In the context of the Higgs model involving gauge and Yukawa interactions with the spontaneous gauge symmetry breaking, we consider $\\lambda \\phi^4$ inflation with non-minimal gravitational coupling, where the Higgs field is identified as inflaton. Since the inflaton quartic coupling is very small, once quantum corrections through the gauge and Yukawa interactions are taken into account, the inflaton effective potential most likely becomes unstable. In order to avoid this problem, we need to impose stability conditions on the effective inflation potential, which lead to not only non-trivial relations amongst the particle mass spectrum of the model, but also correlations between the inflationary predictions and the mass spectrum. For concrete discussion, we investigate the minimal $B-L$ extension of the Standard Model with identification of the $B-L$ Higgs field as inflaton. The stability conditions for the inflaton effective potential fix the mass ratio amongst the $B-L$ gauge boson, the right-handed neutrino...
Systematic study of Coulomb distortion effects in exclusive (e,e'p) reactions
V. Van der Sluys; K. Heyde; J. Ryckebusch; M. Waroquier
1997-01-31
A technique to deal with Coulomb electron distortions in the analysis of (e,e'p) reactions is presented. Thereby, no approximations are made. The suggested technique relies on a partial-wave expansion of the electron wave functions and a multipole decomposition of the electron and nuclear current in momentum space. In that way, we succeed in keeping the computational times within reasonable limits. This theoretical framework is used to calculate the quasielastic (e,e'p) reduced cross sections for proton knockout from the valence shells in $^{16}$O, $^{40}$Ca, $^{90}$Zr and $^{208}$Pb. The final-state interaction of the ejected proton with the residual nucleus is treated within an optical potential model. The role of electron distortion on the extracted spectroscopic factors is discussed.
Harbach, Philipp H P; Schneider, Matthias; Faraji, Shirin; Dreuw, Andreas
2013-03-21
Intermolecular coulombic decay (ICD) is an efficient mechanism of low-energy electron generation in condensed phases and is discussed as their potential source in living cells, tissues, and materials. The first example of ICD as an operating mechanism in real biological systems, that is, in the DNA repair enzymes photolyases, is presented. Photolyase function involves light-induced electron detachment from a reduced flavin adenine dinucleotide (FADH(-)), followed by its transfer to the DNA-lesion triggering repair of covalently bound nucleobase dimers. Modern quantum chemical methods are employed to demonstrate that the transferred electron is efficiently generated via a resonant ICD process between the antenna pigment and the FADH(-) cofactors. PMID:26291360
NASA Astrophysics Data System (ADS)
Ghosh, Aryya; Vaval, Nayana
2014-12-01
Electronically excited atom or molecule in an environment can relax via transferring its excess energy to the neighboring atoms or molecules. The process is called Interatomic or Intermolecular coulombic decay (ICD). The ICD is a fast decay process in environment. Generally, the ICD mechanism predominates in weakly bound clusters. In this paper, we have applied the complex absorbing potential approach/equation-of-motion coupled cluster (CAP/EOMCCSD) method which is a combination of CAP and EOMCC approach to study the lifetime of ICD at various geometries of the molecules. We have applied this method to calculate the lifetime of ICD in Ne-X; X = Ne, Mg, Ar, systems. We compare our results with other theoretical and experimental results available in literature.
Electron dynamics of interatomic Coulombic decay in quantum dots induced by a laser field
NASA Astrophysics Data System (ADS)
Bande, Annika
2013-06-01
In this paper we investigated the dynamics of an electron in the presence of a time-dependent laser field in a model potential for a two-level single-electron semiconductor quantum dot (QD) that is capable of undergoing interatomic Coulombic decay (ICD) together with an electron bound to a neighboring QD. We demonstrate that ICD can be initiated by coupling the two-level QD to either a continuous or a pulsed moderate to strong laser and we obtain the total and partial decay widths of the resonance excited state in agreement with that from the solely decay of the resonance [A. Bande, K. Gokhberg, and L. S. Cederbaum, J. Chem. Phys. 135, 144112 (2011), 10.1063/1.3646205]. A detailed discussion of the effects of direct ionization by the laser in single- or multi-photon process as well as Rabi oscillations is furthermore presented.
Appearance of interatomic Coulombic decay in Ar, Kr, and Xe homonuclear dimers
Lablanquie, P.; Aoto, T.; Hikosaka, Y.; Morioka, Y.; Penent, F.; Ito, K.
2007-10-21
Interatomic Coulombic decay (ICD) is observed in the rare gas homonuclear dimers Ar{sub 2}, Kr{sub 2}, and Xe{sub 2} with photoion spectroscopy techniques. Inner valence ionization of the outer ns shell of these systems is known to create a metastable state that dissociates to form a ground state ion and a neutral excited fragment. Inner valence ionization to form ns satellite states leads to similar dissociations, but the neutral fragment gets all the more excited as the internal energy of the ns satellite state increases. When enough excitation energy is transferred to reach the ionization potential, ICD occurs. ICD threshold is observed to coincide with the position of the A{sup +}A{sup +} ground state in the Franck-Condon region.
Impact of nuclear dynamics on interatomic Coulombic decay in a He dimer
Sisourat, Nicolas; Kryzhevoi, Nikolai V.; Cederbaum, Lorenz S.; Kolorenc, Premysl; Scheit, Simona
2010-11-15
After simultaneous ionization and excitation of one helium atom within the giant weakly bound helium dimer, the excited ion can relax via interatomic Coulombic decay (ICD) and the excess energy is transferred to ionize the neighboring helium atom. We showed [Sisourat et al. Nature Phys. 6, 508 (2010)] that the distributions of the kinetic energy released by the two ions reflect the nodal structures of the ICD-involved vibrational wave functions. We also demonstrated that energy transfer via ICD between the two helium atoms can take place over more than 14 A. We report here a more detailed analysis of the ICD process and of the impact of the nuclear dynamics on the electronic decay. Nonadiabatic effects during the ICD process and the accuracy of the potential energy curve of helium dimer and of the computed decay rates are also investigated.
Faller, Sven
2008-06-15
In this paper we consider general relativity and its combination with scalar quantum electrodynamics (QED) as an effective quantum field theory at energies well below the Planck scale. This enables us to compute the one-loop quantum corrections to the Newton and Coulomb potentials induced by the combination of graviton and photon fluctuations. We derive the relevant Feynman rules and compute the nonanalytical contributions to the one-loop scattering matrix for charged scalars in the nonrelativistic limit. In particular, we derive the post-Newtonian corrections of order Gm/c{sup 2}r from general relativity and the genuine quantum corrections of order G({Dirac_h}/2{pi})/c{sup 3}r{sup 2}.
Equation satisfied by the energy-density functional for electron-electron mutual Coulomb repulsion
Joubert, Daniel P.
2011-10-15
It is shown that the electron-electron mutual Coulomb repulsion energy-density functional V{sub ee}{sup {gamma}}[{rho}] satisfies the equationV{sub ee}{sup {gamma}}[{rho}{sub N}{sup 1}]-V{sub ee}{sup {gamma}}[{rho}{sub N-1}{sup {gamma}}]={integral}d{sup 3}r({delta}V{sub ee}{sup {gamma}}[{rho}{sub N}{sup 1}]/{delta}{rho}{sub N}{sup 1}(r))[{rho}{sub N}{sup 1}(r)-{rho}{sub N-1}{sup {gamma}}(r)], where {rho}{sub N}{sup 1}(r) and {rho}{sub N-1}{sup {gamma}}(r) are N-electron and (N-1)-electron densities determined from the same adiabatic scaled external potential of the N-electron system at coupling strength {gamma}.
Sven Faller
2008-06-19
In this paper we consider general relativity and its combination with scalar quantum electrodynamics (QED) as an effective quantum field theory at energies well below the Planck scale. This enables us to compute the one-loop quantum corrections to the Newton and Coulomb potential induced by the combination of graviton and photon fluctuations. We derive the relevant Feynman rules and compute the nonanalytical contributions to the one-loop scattering matrix for charged scalars in the nonrelativistic limit. In particular, we derive the post-Newtonian corrections of order $Gm/\\text c^2 r$ from general relativity and the genuine quantum corrections of order $G\\hbar/\\text c^3 r^2$.
Analysis of Coulomb breakup experiments of {sup 8}B with a dynamical eikonal approximation
Goldstein, G.; Capel, P.; Baye, D.
2007-08-15
Various measurements of the Coulomb breakup of {sup 8}B are analyzed within the dynamical eikonal approximation using a single description of {sup 8}B. We obtain a good agreement with experiment for different observables measured between 40 and 80 MeV/nucleon. A simple {sup 7}Be-p potential model description of {sup 8}B seems sufficient to describe all observables. In particular, the asymmetry in parallel-momentum distributions due to E1-E2 interferences is well reproduced without any scaling. The projectile-target nuclear interactions seem negligible if data are selected at forward angles. On the contrary, like in previous analyses we observe a significant influence of higher-order effects. The accuracy of astrophysical S factors for the {sup 7}Be(p,{gamma}){sup 8}B reaction at stellar energies extracted from breakup measurements therefore seems difficult to evaluate.
Structure Effects in Collisions Induced by Halo and Weakly Bound Nuclei around the Coulomb Barrier
NASA Astrophysics Data System (ADS)
Scuderi, V.; di Pietro, A.; Acosta, L.; Amorini, F.; Borge, M. J. G.; Figuera, P.; Fisichella, M.; Fraile, L. M.; Gomez-Camacho, J.; Jeppesen, H.; Lattuada, M.; Martel, I.; Milin, M.; Musumarra, A.; Papa, M.; Pellegriti, M. G.; Raabe, R.; Randisi, G.; Rizzo, F.; Santonocito, D.; Sanchez, E. M. R.; Scalia, G.; Tengblad, O.; Torresi, D.; Vidal, A. M.; Zadro, M.
In this contribution, results concerning different reaction channels for the collisions induced by the three Be isotopes, 9,10,11Be, on a 64Zn target at energies around the Coulomb barrier will be presented. The experiments with the radioactive 10,11Be beams were performed at REX-ISOLDE (CERN) whereas the experiment with the stable weakly bound 9Be beam was performed at LNS Catania. Elastic scattering angular distributions have been measured for the three systems 9,10,11Be + 64Zn at the same center of mass energy. The angular distributions were analyzed with optical potentials and reaction cross sections were obtained from optical model calculations, performed with the code PTOLEMY. For the 11Be + 64Zn reaction, the break-up angular distribution was also measured.
Topological defect formation and spontaneous symmetry breaking in ion Coulomb crystals.
Pyka, K; Keller, J; Partner, H L; Nigmatullin, R; Burgermeister, T; Meier, D M; Kuhlmann, K; Retzker, A; Plenio, M B; Zurek, W H; del Campo, A; Mehlstäubler, T E
2013-01-01
Symmetry breaking phase transitions play an important role in nature. When a system traverses such a transition at a finite rate, its causally disconnected regions choose the new broken symmetry state independently. Where such local choices are incompatible, topological defects can form. The Kibble-Zurek mechanism predicts the defect densities to follow a power law that scales with the rate of the transition. Owing to its ubiquitous nature, this theory finds application in a wide field of systems ranging from cosmology to condensed matter. Here we present the successful creation of defects in ion Coulomb crystals by a controlled quench of the confining potential, and observe an enhanced power law scaling in accordance with numerical simulations and recent predictions. This simple system with well-defined critical exponents opens up ways to investigate the physics of non-equilibrium dynamics from the classical to the quantum regime. PMID:23921564
NASA Astrophysics Data System (ADS)
Nandy, Subhajit; Chaudhury, Pinaki; Bhattacharyya, S. P.
2010-06-01
We present a genetic algorithm based investigation of structural fragmentation in dicationic noble gas clusters, Arn+2, Krn+2, and Xen+2, where n denotes the size of the cluster. Dications are predicted to be stable above a threshold size of the cluster when positive charges are assumed to remain localized on two noble gas atoms and the Lennard-Jones potential along with bare Coulomb and ion-induced dipole interactions are taken into account for describing the potential energy surface. Our cutoff values are close to those obtained experimentally [P. Scheier and T. D. Mark, J. Chem. Phys. 11, 3056 (1987)] and theoretically [J. G. Gay and B. J. Berne, Phys. Rev. Lett. 49, 194 (1982)]. When the charges are allowed to be equally distributed over four noble gas atoms in the cluster and the nonpolarization interaction terms are allowed to remain unchanged, our method successfully identifies the size threshold for stability as well as the nature of the channels of dissociation as function of cluster size. In Arn2+, for example, fissionlike fragmentation is predicted for n =55 while for n =43, the predicted outcome is nonfission fragmentation in complete agreement with earlier work [Golberg et al., J. Chem. Phys. 100, 8277 (1994)].
Breakup threshold anomaly for the {sup 8}B + {sup 58}Ni system at near-Coulomb barrier energies
Gomez Camacho, A.; Aguilera, E. F.; Gomes, P. R. S.; Lubian, J.
2011-09-15
By using recent fusion cross section measurements for the system {sup 8}B + {sup 58}Ni, a simultaneous analysis of elastic scattering, fusion, and total reaction cross sections is performed for the weakly bound system {sup 8}B + {sup 58}Ni at energies close to the Coulomb barrier. The analysis is carried out with an optical potential with fusion and direct reaction parts (i.e., the nuclear polarization potential U is split into a volume part U{sub F}, which accounts for fusion reactions and a surface part U{sub DR}, responsible for direct reactions). The parameters of the Woods-Saxon potentials are determined by a {chi}{sup 2} analysis of the data. The presence of the threshold anomaly is investigated from the energy dependence of both the fusion and direct reaction parts of the polarization potential.
Challenges in calculating molecular systems with Coulomb interactions
NASA Astrophysics Data System (ADS)
Kirnosov, Nikita; Sharkey, Keeper; Adamowicz, Ludwik
2014-03-01
The highly accurate quantum mechanical calculations are not only crucial for high-resolution experimental data verification, but may also serve as a guide in the field of exotic systems exploration. Including all non-relativistic effects in a single-step variational approach and rigorously separating out the center of mass motion allows us to build a reliable model for calculating bound states of molecular systems with Coulomb interactions. In these calculations the wave function of the system is expanded in terms of explicitly correlated Gaussian (ECG) basis functions. Examples of calculations of energies and other properties of some molecular systems will be presented.
A proposal for Coulomb assisted laser cooling of piezoelectric semiconductors
Nia, Iman Hassani; Mohseni, Hooman
2014-07-28
Anti-Stokes laser cooling of semiconductors as a compact and vibration-free method is very attractive. While it has achieved significant milestones, increasing its efficiency is highly desirable. The main limitation is the lack of the pristine material quality with high luminescence efficiency. Here, we theoretically demonstrate that the Coulomb interaction among electrons and holes in piezoelectric heterostructures could lead to coherent damping of acoustic phonons; rendering a significantly higher efficiency that leads to the possibility of cooling a broad range of semiconductors.
The Coulomb excitations of Bernal bilayer graphene under external fields
Wu, Jhao-Ying; Lin, Ming-Fa
2014-03-31
We study the field effects on the Coulomb excitation spectrum of Bernal bilayer graphene by using the tight-binding model and the random-phase approximation. The electric field opens the band gap and creates the saddle points, the latter brings about a prominent interband plasmon. On the other hand, the magnetic field induces the dispersionless Landau levels (LLs) that causes the inter-LL plasmons. The two kinds of field-induced plasmon modes can be further tuned by the magnitude of momentum transfer and the field strength. The predicted results may be further validated by the inelastic light-scattering or high-resolution electron-energy-loss spectroscopy (HREELLS)
Screening corrections to the Coulomb crystal elastic moduli
NASA Astrophysics Data System (ADS)
Baiko, D. A.
2015-08-01
Corrections to elastic moduli, including the effective shear modulus, of a solid neutron star crust due to electron screening are calculated. At any given mass density, the crust is modelled as a body-centred cubic Coulomb crystal of fully ionized atomic nuclei of a single type with a polarizable charge-compensating electron background. Motion of the nuclei is neglected. The electron polarization is described by a simple Thomas-Fermi model of exponential electron screening. The results of numerical calculations are fitted by convenient analytic formulae. They should be used for precise neutron star oscillation modelling, a rapidly developing branch of stellar seismology.
Nonclassical light generation by Coulomb blockade of resonant tunneling
NASA Astrophysics Data System (ADS)
Imamog¯lu, A.; Yamamoto, Y.
1992-12-01
We show that the Coulomb blockade of resonant tunneling in semiconductor heterojunctions creates correlations between single-charge tunneling and single-photon emission events. When driven by a constant-current source, a mesoscopic p-i-i-i-n junction generates a regulated single-photon stream by single-electron-to-single-photon conversion. Under constant-voltage operation, the photon stream generated by the junction is antibunched and sub-Poissonian. The single-electron charging energy of the heterostructure has to exceed the width of the resonant subband and the characteristic energy of the thermal fluctuations for these correlations to be observable.
Quantum calculations of Coulomb reorientation for sub-barrier fusion.
Simenel, C; Chomaz, Ph; de France, G
2004-09-01
Classical mechanics and time dependent Hartree-Fock (TDHF) calculations of heavy ions collisions are performed to study the rotation of a deformed nucleus in the Coulomb field of its partner. This reorientation is shown to be independent of the charges and relative energy of the partners. It only depends upon the deformations and inertias. TDHF calculations predict an increase by 30% of the induced rotation due to quantum effects while the nuclear contribution seems negligible. This reorientation modifies strongly the fusion cross section around the barrier for light deformed nuclei on heavy collision partners. For such nuclei a hindrance of the sub-barrier fusion is predicted. PMID:15447400
A nonlinear Bloch model for Coulomb interaction in quantum dots
Bidegaray-Fesquet, Brigitte Keita, Kole; CNRS, LJK, BP 53, 38041 Grenoble Cedex
2014-02-15
In this paper, we first derive a Coulomb Hamiltonian for electron–electron interaction in quantum dots in the Heisenberg picture. Then we use this Hamiltonian to enhance a Bloch model, which happens to be nonlinear in the density matrix. The coupling with Maxwell equations in case of interaction with an electromagnetic field is also considered from the Cauchy problem point of view. The study is completed by numerical results and a discussion about the advisability of neglecting intra-band coherences, as is done in part of the literature.
Interplay of initial deformation and Coulomb proximity on nuclear decay
Hudan, S.; Alfaro, R.; Beaulieu, L.; Davin, B.; Larochelle, Y.; Lefort, T.; Viola, V.E.; Xu, H.; Yanez, R.; Souza, R.T. de; Charity, R. J.; Sobotka, L. G.; Liu, T. X.; Liu, X. D.; Lynch, W. G.; Shomin, R.; Tan, W. P.; Tsang, M. B.; Vander Molen, A.; Wagner, A.
2004-09-01
Alpha particles emitted from an excited projectilelike fragment (PLF{sup *}) formed in a peripheral collision of two intermediate-energy heavy ions exhibit a strong preference for emission towards the targetlike fragment. The interplay of the initial deformation of the PLF{sup *} caused by the reaction, Coulomb proximity, and the rotation of the PLF{sup *} results in the observed anisotropic angular distribution. Changes in the shape of the angular distribution with excitation energy are interpreted as being the result of forming more elongated initial geometries in the more peripheral collisions.
Universal monopole scaling near transitions from the Coulomb phase.
Powell, Stephen
2012-08-10
Certain frustrated systems, including spin ice and dimer models, exhibit a Coulomb phase at low temperatures, with power-law correlations and fractionalized monopole excitations. Transitions out of this phase, at which the effective gauge theory becomes confining, provide examples of unconventional criticality. This Letter studies the behavior at nonzero monopole density near such transitions, using scaling theory to arrive at universal expressions for the crossover phenomena. For a particular transition in spin ice, quantitative predictions are made by mapping to the XY model and confirmed using Monte Carlo simulations. PMID:23006280
Density of states and critical behavior of the Coulomb glass.
Surer, Brigitte; Katzgraber, Helmut G; Zimanyi, Gergely T; Allgood, Brandon A; Blatter, Gianni
2009-02-13
We present zero-temperature simulations for the single-particle density of states of the Coulomb glass. Our results in three dimensions are consistent with the Efros and Shklovskii prediction for the density of states. Finite-temperature Monte Carlo simulations show no sign of a thermodynamic glass transition down to low temperatures, in disagreement with mean-field theory. Furthermore, the random-displacement formulation of the model undergoes a transition into a distorted Wigner crystal for a surprisingly broad range of the disorder strength. PMID:19257630
Modeling bound-to-continuum terahertz quantum cascade lasers: The role of Coulomb interactions
Jirauschek, Christian; Lugli, Paolo; 10.1063/1.3276160
2011-01-01
Based on an ensemble Monte Carlo analysis, we show that Coulomb interactions play a dominant role in bound-to-continuum terahertz quantum cascade lasers and thus require careful modeling. Coulomb interactions enter our simulation in the form of space charge effects as well as Coulomb scattering events. By comparison to a full many-subband Coulomb screening model, we show that simplified approaches produce considerable deviations for such structures. Also the spin dependence of electron-electron scattering has to be adequately considered. Moreover, we demonstrate that iterative Schr\\"{o}dinger-Poisson and carrier transport simulations are necessary to correctly account for space charge effects.
The influence of the Coulomb exchange term on nuclear single-proton resonances
Shu-Yang Wang; Zhong-Lai Zhu; Zhong-Ming Niu
2015-10-27
Nuclear single-proton resonances are sensitive to the Coulomb field, while the exchange term of Coulomb field is usually neglected due to its nonlocality. By combining the complex scaling method with the relativistic mean-field model, the influence of the Coulomb exchange term on the single-proton resonances is investigated by taking Sn isotopes and $N=82$ isotones as examples. It is found that the Coulomb exchange term reduces the single-proton resonance energy within the range of $0.4-0.6$ MeV, and lead to similar isotopic and isotonic trends of the resonance energy as those without the Coulomb exchange term. Moreover, the single-proton resonance width is also reduced by the Coulomb exchange term, whose influence generally decreases with the increasing neutron number and increases with the increasing proton number. However, the influence of the Coulomb exchange term cannot change the trend of the resonance width with respect to the neutron number and proton number. Furthermore, the influence of the Coulomb exchange term on the resonance width is investigated for the doubly magic nuclei $^{40}$Ca, $^{56,78}$Ni, $^{100,132}$Sn, and $^{208}$Pb. It is found that the Coulomb exchange term reduces the proton resonance width within $0.2$ MeV, whose magnitude depends on the specific nucleus and the quantum numbers of resonant states.
Third order Bose-Einstein correlations by means of Coulomb wave function revisited
Minoru Biyajima; Takuya Mizoguchi; Naomichi Suzuki
2006-03-22
In previous works, in order to include correction by the Coulomb wave function in Bose-Einstein correlations (BEC), the two-body Coulomb scattering wave functions have been utilized in the formulation of three-body BEC. However, the three-body Coulomb scattering wave function, which satisfies approximately the three-body Coulomb scattering Schrodinger equation, cannot be written by the product of the two-body scattering wave functions. Therefore, we reformulate the three-body BEC, and reanalyze the data. A set of reasonable parameters is obtained.
NASA Astrophysics Data System (ADS)
Tie, M.; Dhirani, A.-A.
2015-04-01
We study the influence of Coulomb effects on conductance (g ) of 1,4-butanedithiol-linked gold nanoparticle (NP) films near a percolation insulator-to-metal transition. On the insulating side, g ˜exp [-(T?/T ) 1 /2] , where T is absolute temperature, a behavior predicted by Efros-Shklovskii's theory for charges optimizing pathways that accommodate Coulomb charging barriers. On the metallic side below ˜20 K, g varies linearly with T1 /2. Such a correction to g (T =0 ) is predicted by Altshuler-Aronov's theory for Fermi liquid metals when disorder mediates electron-electron (e -e ) Coulomb interactions. Remarkably, in the present system, the T1 /2 component of g is significant compared to g (T =0 ) , and fitting to Boltzmann's transport theory yields elastic scattering lengths that are anomalously small—much smaller than the distance between atoms (Ioffe-Regel limit required for metals). Previous studies of materials such as fullerites, layered organic salts, and transition metal compounds have also reported such anomalously small scattering lengths and large T1 /2 components and attributed them to strong Coulomb mediated e -e correlations, which we believe is likely the case in the present system as well. This study highlights a potential opportunity to use molecularly linked nanoparticle films as a platform to study strongly correlated electrons in a controlled fashion.
P. Gerhold; K. Jansen
2009-12-02
We study a lattice Higgs-Yukawa model emulating the same Higgs-fermion coupling structure as in the Higgs sector of the electroweak Standard Model, in particular, obeying a Ginsparg-Wilson version of the underlying SU(2) x U(1) symmetry, being a global symmetry here due to the neglection of gauge fields in this model. In this paper we present our results on the cutoff-dependent upper Higgs boson mass bound at several selected values of the cutoff parameter.
Corresponding states law for a generalized Lennard-Jones potential.
Orea, P; Romero-Martínez, A; Basurto, E; Vargas, C A; Odriozola, G
2015-07-14
It was recently shown that vapor-liquid coexistence densities derived from Mie and Yukawa models collapse to define a single master curve when represented against the difference between the reduced second virial coefficient at the corresponding temperature and that at the critical point. In this work, we further test this proposal for another generalization of the Lennard-Jones pair potential. This is carried out for vapor-liquid coexistence densities, surface tension, and vapor pressure, along a temperature window set below the critical point. For this purpose, we perform molecular dynamics simulations by varying the potential softness parameter to produce from very short to intermediate attractive ranges. We observed all properties to collapse and yield master curves. Moreover, the vapor-liquid curve is found to share the exact shape of the Mie and attractive Yukawa. Furthermore, the surface tension and the logarithm of the vapor pressure are linear functions of this difference of reduced second virial coefficients. PMID:26178115
Corresponding states law for a generalized Lennard-Jones potential
NASA Astrophysics Data System (ADS)
Orea, P.; Romero-Martínez, A.; Basurto, E.; Vargas, C. A.; Odriozola, G.
2015-07-01
It was recently shown that vapor-liquid coexistence densities derived from Mie and Yukawa models collapse to define a single master curve when represented against the difference between the reduced second virial coefficient at the corresponding temperature and that at the critical point. In this work, we further test this proposal for another generalization of the Lennard-Jones pair potential. This is carried out for vapor-liquid coexistence densities, surface tension, and vapor pressure, along a temperature window set below the critical point. For this purpose, we perform molecular dynamics simulations by varying the potential softness parameter to produce from very short to intermediate attractive ranges. We observed all properties to collapse and yield master curves. Moreover, the vapor-liquid curve is found to share the exact shape of the Mie and attractive Yukawa. Furthermore, the surface tension and the logarithm of the vapor pressure are linear functions of this difference of reduced second virial coefficients.
Coulomb excitation of a {sup 78}Rb radioactive beam.
Schwartz, J.
1998-11-18
In order to test the feasibility of Coulomb excitation of radioactive projectiles with low beam energies and intensities, they have produced a secondary radioactive beam of {sup 78}Rb and Coulomb re-excited it. The beam was produced in the fusion evaporation reaction {sup 24}Mg({sup 58}Ni,3pn){sup 78}Rb at a beam energy of 260 MeV, using the Argonne National Laboratory ATLAS accelerator. The residues of interest were separated from other reaction products and non-interacting beam using the Fragment Mass Analyzer (FMA). The beam leaving the FMA was {sup 78}Kr and {sup 78}Rb{sup gs,m1,m2}, which was refocused onto a {sup 58}Ni secondary target. They have extracted a spectrum of {gamma}-rays associated with re-excitation of A = 78 isobars. The re-excitation of stable {sup 78}Kr was observed, which serves as a reference. Gamma-rays associated with excitation of {sup 78}Rb{sup gs,m1,m2} were also seen. The measured yields indicate that all the {sup 78}Rb states are highly deformed.
Quasiequilibrium Characterization of Mixed-Ion Coulomb Crystals
NASA Astrophysics Data System (ADS)
Okada, Kunihiro; Ichikawa, Masanari; Wada, Michiharu; Schuessler, Hans A.
2015-11-01
We demonstrate the application of reliable methods to determine both the average micromotion energies and the number of sympathetically cooled ions (SCIs) embedded in mixed-ion Coulomb crystals in a linear Paul trap. The number of the SCIs and the micromotion energies for the observed mixed-ion crystals are determined by comparing experimentally obtained images with molecular-dynamics simulations, where the kinetic energies of SCIs trapped in rf fields are averaged in cold elastic collisions between the laser-cooled ions and virtual very light atoms. This combined method quickly achieves the quasiequilibrium state of large mixed Coulomb crystals with over 103 ions, regardless of the initial conditions, and shows that the previously used pseudopotential-based adiabatic approximations should be replaced by such molecular-dynamics simulations. In addition, a pattern-matching recognition procedure is introduced which objectively ascertains the number of ions. We also apply the presented characterization method to determine the reaction-rate constant between slow acetonitrile molecules and sympathetically cooled Ne+ ions at a translational temperature lower than 10 K.
Revision of the Coulomb logarithm in the ideal plasma
Mulser, P. Alber, G.; Murakami, M.
2014-04-15
The standard picture of the Coulomb logarithm in the ideal plasma is controversial, the arguments for the lower cut off need revision. The two cases of far subthermal and of far superthermal electron drift motions are accessible to a rigorous analytical treatment. We show that the lower cut off b{sub min} is a function of symmetry and shape of the shielding cloud, it is not universal. In the subthermal case, shielding is spherical and b{sub min} is to be identified with the de Broglie wavelength; at superthermal drift the shielding cloud exhibits cylindrical (axial) symmetry and b{sub min} is the classical parameter of perpendicular deflection. In both situations, the cut offs are determined by the electron-ion encounters at large collision parameters. This is in net contrast to the governing standard interpretation that attributes b{sub min} to the Coulomb singularity at vanishing collision parameters b and, consequently, assigns it universal validity. The origin of the contradictions in the traditional picture is analyzed.
Mechanical model of the Lorentz force and Coulomb interaction
NASA Astrophysics Data System (ADS)
Dmitriyev, Valery
2008-09-01
The centripetal and Coriolis accelerations experienced by a cart traveling over a rotating turntable are usually calculated proceeding from the known kinematics of the problem. Respective forces can be regarded as due to the entrainment of the cart in the moving solid environs. We extend the approach to the general case of a particle entrained in the flow of the surrounding medium. The expression for the driving force on the particle obtained from the kinematics of the entrainment prescribed appears to be isomorphic to the Lorentz and Coulomb force on a positive electric charge. The inverse direction of the electromagnetic force on a negative charge implies that a growing applied flow induces the upstream motion of the particle. A possible microscopic mechanism for it may be the Magnus force dynamics of a kink in a vortex tangle. The loop on a straight vortex filament can be taken as a model of the electron, the loop with a cavitation models the positron. The Lorentz force is concerned with the Coriolis acceleration. The Coulomb interaction is due to the centripetal or centrifugal force that arises in the turbophoresis of the kink in the perturbation field generated in the medium by the center of pressure.
Slave rotor approach to dynamically screened Coulomb interactions in solids
NASA Astrophysics Data System (ADS)
Krivenko, I. S.; Biermann, S.
2015-04-01
Recent studies of dynamical screening of the electronic Coulomb interactions in solids have revived interest in lattice models of correlated fermions coupled to bosonic degrees of freedom (Hubbard-Holstein-type models). We propose a new dynamical mean-field-based approach to dynamically screened Coulomb interactions. In the effective Anderson-Holstein model, a transformation to slave rotors [S. Florens and A. Georges, Phys. Rev. B 66, 165111 (2002), 10.1103/PhysRevB.66.165111] is performed to decouple the dynamical part of the interaction. This transformation allows for a systematic derivation and analysis of recently introduced approximate schemes for the solution of dynamical impurity problems, in particular, the Bose factor ansatz within the dynamic atomic limit approximation (DALA) with and without Lang-Firsov correction. More importantly still, it suggests an optimized choice for a Bose factor in the sense of the variational principle of Feynman and Peierls. We demonstrate the accuracy of our scheme and present a comparison to calculations within the DALA.
Theory of rolling: Solution of the Coulomb problem
NASA Astrophysics Data System (ADS)
Cherepanov, G. P.
2014-01-01
A theory of rolling of round bodies in the normal mode with adhesion conditions satisfied on the entire contact area is proposed. This theory refines the classical Coulomb's theory of rolling in which the rolling moment is directly proportional to the pressing force (e.g., the weight of the rolling body). The rolling moment of cylinders is found to be directly proportional to the pressing force raised to a power of 3/2, and the rolling moment of balls and tori is proportional to the pressing force raised to a power of 4/3. It is shown that the normal mode of uniform rolling can only be provided for a certain ratio of the elastic constants of the materials of the round body and the base forming an ideal pair. The Coulomb problem is solved for the cases of rolling of an elastic cylinder over an elastic half-space, of an elastic ball over an elastic half-space, of an elastic torus over an elastic half-space, and of a cylinder and ball over a tightly stretched membrane. The rolling law is derived for such cases. The rolling friction coefficients, the rolling moment, and the rolling friction force are calculated.
Universality and the Coulomb dissociation of two-neutron halos
NASA Astrophysics Data System (ADS)
Phillips, Danel; Acharya, Bijaya; Hagen, Philipp; Hammer, Hans-Werner
2015-04-01
In the limit of large two-body s-wave scattering length few-body systems display universality: their properties are independent of the details of interactions. Such universality is present in halo nuclei where two neutrons orbit a tightly bound nuclear core. There, the neutron-neutron (nn) scattering length is much larger than the range of the nn force, and, if the neutron-core scattering length obeys | a | >> R , the system can be described by an effective field theory (EFT) based on this separation of scales. In this ``Halo EFT'' the degrees of freedom are the neutrons and the core; core structure is included at higher order in the EFT. At leading order (LO) in the R / a expansion one three-body datum is needed as input to obtain renormalized predictions for core-n-n observables. Here we take that datum to be the two-neutron separation energy, S2 n, of a 2n-halo nucleus. At LO all properties of a 2n-halo are functions of S2 n and the two-body scattering lengths. In particular, its Coulomb dissociation spectrum is a universal function of these parameters. We compute that function, and compare it to experimental data from 11 Li. We also discuss how measurements of the Coulomb dissociation of 22 C can constrain both its S2 n and properties of 21 C. Research supported by the US Department of Energy and the DFG.
Freezing lines of colloidal Yukawa spheres. I. A Rogers-Young integral equation study
NASA Astrophysics Data System (ADS)
Gapinski, Jacek; Nägele, Gerhard; Patkowski, Adam
2012-01-01
Using the Rogers-Young (RY) integral equation scheme for the static structure factor combined with the one-phase Hansen-Verlet (HV) freezing rule, we study the equilibrium structure and two-parameter freezing lines of colloidal particles with Yukawa-type pair interactions representing charge-stabilized silica spheres suspended in dimethylformamide (DMF). Results are presented for a vast range of concentrations, salinities and effective charges covering particles with masked excluded-volume interactions. The freezing lines were obtained for the low-charge and high-charge solutions of the static structure factor, for various two-parameter sets of experimentally accessible system parameters. All RY-HV based freezing lines can be mapped on a universal fluid-solid coexistence line in good agreement with computer simulation predictions. The RY-HV calculations extend the freezing lines obtained in earlier simulations to a broader parameter range. The experimentally observed fluid-bcc-fluid reentrant transition of charged silica spheres in DMF can be explained using the freezing lines obtained in this work.
Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector
Aad, G.
2015-04-21
Results of a search for H ? ?? decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb^{–1} and 20.3 fb^{–1} at centre-of-mass energies of ?s=7 TeV and ?s=8 TeV respectively. All combinations of leptonic (? ? ???¯ with ? = e, ?) and hadronic (? ? hadrons ?) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalized to the Standard Model expectation, of ? = 1.43_{–0.37}^{+0.43} is consistent with the predicted Yukawa coupling strength in the Standard Model.
Freezing lines of colloidal Yukawa spheres. II. Local structure and characteristic lengths
Gapinski, Jacek Patkowski, Adam; Nägele, Gerhard
2014-09-28
Using the Rogers-Young (RY) integral equation scheme for the static pair correlation functions combined with the liquid-phase Hansen-Verlet freezing rule, we study the generic behavior of the radial distribution function and static structure factor of monodisperse charge-stabilized suspensions with Yukawa-type repulsive particle interactions at freezing. In a related article, labeled Paper I [J. Gapinski, G. Nägele, and A. Patkowski, J. Chem. Phys. 136, 024507 (2012)], this hybrid method was used to determine two-parameter freezing lines for experimentally controllable parameters, characteristic of suspensions of charged silica spheres in dimethylformamide. A universal scaling of the RY radial distribution function maximum is shown to apply to the liquid-bcc and liquid-fcc segments of the universal freezing line. A thorough analysis is made of the behavior of characteristic distances and wavenumbers, next-neighbor particle coordination numbers, osmotic compressibility factor, and the Ravaché-Mountain-Streett minimum-maximum radial distribution function ratio.
Phase equilibria and interfacial properties of two-dimensional Yukawa fluids
G. A. Méndez-Maldonado; M. González-Melchor; J. Alejandre
2012-07-13
Molecular dynamics simulations of two-dimensional soft Yukawa fluids are performed to analyze the effect that the range of interaction has on coexisting densities and line tension. The attractive one-component fluid and equimolar mixtures containing positive and negative particles are studied at different temperatures to locate the region where the vapor-solid and vapor-liquid phases are stable. When the range of interaction decreases, the critical temperature of the attractive one-component systems decreases. However, for the charged mixtures it increases, and this opposite behaviour is understood in terms of the repulsive interactions which are dominant for these systems. The stable phase diagram of two-dimensional fluids is defined for smaller values of the decay parameter \\lambda\\ than that of fluids in three dimensions. The two-dimensional attractive one-component fluid has stable liquid-vapor phase diagram for values of \\lambda<3, in contrast to the three-dimensional case, where stability has been observed even for values of \\lambda<15. The same trend is observed in equimolar mixtures of particles carrying opposite charges.
Freezing lines of colloidal Yukawa spheres. II. Local structure and characteristic lengths
NASA Astrophysics Data System (ADS)
Gapinski, Jacek; Nägele, Gerhard; Patkowski, Adam
2014-09-01
Using the Rogers-Young (RY) integral equation scheme for the static pair correlation functions combined with the liquid-phase Hansen-Verlet freezing rule, we study the generic behavior of the radial distribution function and static structure factor of monodisperse charge-stabilized suspensions with Yukawa-type repulsive particle interactions at freezing. In a related article, labeled Paper I [J. Gapinski, G. Nägele, and A. Patkowski, J. Chem. Phys. 136, 024507 (2012)], this hybrid method was used to determine two-parameter freezing lines for experimentally controllable parameters, characteristic of suspensions of charged silica spheres in dimethylformamide. A universal scaling of the RY radial distribution function maximum is shown to apply to the liquid-bcc and liquid-fcc segments of the universal freezing line. A thorough analysis is made of the behavior of characteristic distances and wavenumbers, next-neighbor particle coordination numbers, osmotic compressibility factor, and the Ravaché-Mountain-Streett minimum-maximum radial distribution function ratio.
Probing the anomalous FCNC top-Higgs Yukawa couplings at the Large Hadron Electron Collider
NASA Astrophysics Data System (ADS)
Liu, Wei; Sun, Hao; Wang, XiaoJuan; Luo, Xuan
2015-10-01
In this paper, we study the anomalous flavor changing neutral current Yukawa interactions between the top quark, the Higgs boson, and either an up or charm quark (t q H ,q =u ,c ). We probe these couplings in e-p ??et ¯ ??eH q ¯ and the channel e-p ??eH b . Both channels are induced by charged current interactions through e-p collision at the Large Hadron Electron Collider (LHeC). We study the signatures with the Higgs decay modes H ?? ? ,b b ¯ and ?+?-. Our results show that the flavor changing couplings ?t q H can be probed down to a value of 0.0162 in e-p ??et ¯ ??eH q ¯ with H ?b b ¯ at a 14 TeV LHeC with a 150 GeV electron beam and 200 fb-1 luminosity. This value of the coupling corresponds to the branching ratio Br (t ?q H )=1.34 ×10-4 .
Role of charge localization on the Coulomb fragmentation of large metal clusters: A model study
Calvo, F.
2006-10-15
The Coulomb fragmentation patterns of multicharged sodium clusters Na{sub n}{sup Q+} are theoretically investigated in broad size range 55{<=}n{<=}923 and for charges Q{<=}50 below and across the Rayleigh stability limit. An empirical many-body potential is used to model the main cohesion energy in the neutral clusters. The extra electrostatic interaction is described using a specific fluctuating-charge model, which correctly reproduces the surface localization but can be tuned to represent a uniform distribution. Molecular dynamics simulations are performed by sampling the liquidlike state of the neutral clusters, then charging them instantaneously and following their fragmentation behavior. In order to achieve meaningful statistics, an extended Lagrangian scheme is used to accelerate the propagation when a surface charge is simulated. It is generally found that clusters with charge on the surface decay by emitting small fragments, essentially monomers, both above and below the Rayleigh limit. For fissilities close to 1, large clusters lost about 30%-40% of their charge but only a few percent of the mass is lost. These values agree with experimental data on mesoscopic conducting droplets. In contrast, the uniform charge distribution leads to fission into two or more large fragments when the fissility parameter approaches 1 and the fragmentation becomes more and more asymmetric as the charge increases. The distributions of fragments, average fragment sizes, and charges are estimated. The time scales for fragmentation show that fission into large fragments is much slower than the emission of surface atoms, particularly close to the Rayleigh threshold. In the case of surface-charged clusters, Coulomb multifragmentation appears to be mainly isotropic.
Van Hooydonk, G
2000-11-01
Following recent work in search for a universal function (Van Hooydonk, Eur. J. Inorg. Chem., (1999), 1617), we test four symmetric +/- a(n)Rn potentials for reproducing molecular potential energy curves (PECs). Classical gauge symmetry for 1/R-potentials results in generic left right asymmetric PECs. A pair of symmetric perturbed Coulomb potentials is quantitatively in accordance with observed PECs. For a bond, a four-particle system, charge inversion (a parity effect, atom chirality) is the key to explain this shape generically. A parity adapted Hamiltonian reduces from ten to two terms and to a soluble Bohr-like formula, a Kratzer (1 - Re/R)2 potential. The result is similar to the combined action of spin and wave function symmetry upon the Hamiltonian in Heitler-London theory. Analytical perturbed Coulomb functions varying with (1 - Re/R) scale attractive and repulsive branches of PECs for 13 bonds H2, HF, LiH, KH, AuH, Li2, LiF, KLi, NaCs, Rb2, RbCs, Cs2 and I2 in a single straight line. The 400 turning points for 13 bonds are reproduced with a deviation of 0.007 A at both branches. For 230 points at the repulsive side, the deviation is 0.003 A. The perturbed electrostatic Coulomb law is a universal molecular function. Ab initio zero molecular parameter functions give PECs of acceptable quality, just using atomic ionisation energies. The function can be used as a model potential for inverting levels and gives a first principle's comparison of short- and long-range interactions, important for the study of cold atoms. Wave-packet dynamics, femto-chemistry applied to the crossing of covalent and ionic curves, can provide evidence for this theory. We anticipate this scale/shape invariant scheme applies to smaller scales in nuclear and high-energy particle physics. For larger gravitational scales (Newton 1/R potentials), problems with super-unification are discussed. Reactions between hydrogen and antihydrogen, feasible in the near future, will probably produce normal H2. PMID:11075672
Evidence for 2kF electronelectron scattering processes in Coulomb drag
Eisenstein, Jim
Evidence for 2kF electronÂelectron scattering processes in Coulomb drag M. Kellogga , J and calculations of Coulomb drag between two low density, closely spaced, two-dimensional electron systems are reported. The experimentally measured drag exceeds that calculated in the random phase approximation
Coulomb drag in mesoscopic rings T. V. Shahbazyan and S. E. Ulloa
Ulloa, Sergio E.
Coulomb drag in mesoscopic rings T. V. Shahbazyan and S. E. Ulloa Department of Physics 27 January 1997 We develop a Luttinger-liquid theory of the Coulomb drag of persistent currents nondissipative drag depends strongly on the relative parity of the electron numbers. We also show