NSDL National Science Digital Library
Iacovella, Christopher R.
2007-05-09
Plot of the Yukawa potential showing the hard=core formulation of the Yukawa Potential for several combinations of ? and ?. The Yukawa pair potential is used to model the interaction between charge stabilized colloids. It is a purely repulsive potential when considered two particles with like charge; oppositely charged particles will exhibit an attraction.
NASA Technical Reports Server (NTRS)
Straton, Jack C.
1989-01-01
The class of integrals containing the product of N 1s hydrogenic orbitals and M Coulomb or Yukawa potentials with m plane waves is investigated analytically. The results obtained by Straton (1989) are extended and generalized. It is shown that the dimensionality of the entire class can be reduced from 3m to M+N-1.
FMM-YUKAWA: AN ADAPTIVE FAST MULTIPOLE METHOD FOR SCREENED COULOMB INTERACTIONS
FMM-YUKAWA: AN ADAPTIVE FAST MULTIPOLE METHOD FOR SCREENED COULOMB INTERACTIONS By Jingfang HuangÂ0436 Phone: 612/624-6066 Fax: 612/626-7370 URL: http://www.ima.umn.edu #12;FMM-Yukawa: An Adaptive Fast. Key words: Fast Multipole Method; Screened Coulomb Potential; Yukawa Potential; Diagonal Translation
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.
I. I. Guseinov
2009-03-30
Using one-range addition theorems for noninteger n Slater type orbitals and Coulomb-Yukawa like correlated interaction potentials with noninteger indices obtained by the author with the help of complete orthonormal sets of exponential type orbitals, the series of expansion formulas are established for the potential produced by molecule, and the potential energy of interaction between molecules through the radius vectors of nuclei of molecules, and the linear combination coefficients of molecular orbitals. The formulae obtained are useful especially for the study of interaction between atomic-molecular systems containing any number of closed and open shells when the Hartree-Fock-Roothaan and explicitly correlated methods are employed. The relationships obtained are valid for the arbitrary values of indices and screening constants of orbitals and correlated interaction potentials.
NASA Technical Reports Server (NTRS)
Straton, Jack C.
1989-01-01
The Fourier transform of the multicenter product of N 1s hydrogenic orbitals and M Coulomb or Yukawa potentials is given as an (M+N-1)-dimensional Feynman integral with external momenta and shifted coordinates. This is accomplished through the introduction of an integral transformation, in addition to the standard Feynman transformation for the denominators of the momentum representation of the terms in the product, which moves the resulting denominator into an exponential. This allows the angular dependence of the denominator to be combined with the angular dependence in the plane waves.
The screened Coulomb (Yukawa) charged hard sphere binary fluid
NASA Astrophysics Data System (ADS)
Leote de Carvalho, R. J. F.; Evans, R.
The screened Coulomb (Yukawa) restricted primitive model (Y RPM) of a binary fluid is treated within the one-pole generalized mean-spherical approximation (GMSA). Fluid phase behaviour and structure are compared with the corresponding results for the unscreened Coulombic RPM. Screening increases the critical density and temperature above the values for the RPM and decreases the width of the liquid-gas coexistence curves. The asymptotics of pairwise correlation functions and the genesis of disorder lines in the phase diagram are discussed. These lines are where the ultimate decay of total density or concentration (charge) correlations crosses over from monotonic to oscillatory. The location of the disorder lines is strongly dependent on the range of the Yukawa potentials. We show that very shortrange interionic potentials (Yukawa models) can give rise to correlation functions which are difficult to distinguish (at all interionic separations) from those obtained for the long-range Coulombic case for structurally equivalent thermodynamic states, reinforcing the idea that pronounced charge ordering is not unique to Coulombic interactions but can occur whenever the interaction potential between different species (AB) is strongly attractive and the potentials between identical species (AA and BB) are repulsive. Although the GMSA generally improves upon the MSA, we show that it leads to artificial peaks (not found in simulation) for correlations g(r)between identical ionic species at separations r close to ionic contract when the density is high and the temperature is low. This failing, which occurs for both the RPM and Y RPM, reflects the sensitivity of g(r) near contact to approximations.ii
Relativistic new Yukawa-like potential and tensor coupling
Sameer M. Ikhdair; Majid Hamzavi
2012-10-04
We approximately solve the Dirac equation for a new suggested generalized inversely quadratic Yukawa (GIQY) potential including a Coulomb-like tensor interaction with arbitrary spin-orbit coupling quantum number In the framework of the spin and pseudospin (p-spin) symmetry, we obtain the energy eigenvalue equation and the corresponding eigenfunctions, in closed form, by using the parametric Nikiforov-Uvarov (NU) method. The numerical results show that the Coulomb-like tensor interaction, removes degeneracies between spin and p-spin state doublets. The Dirac solutions in the presence of exact spin symmetry are reduced to Schr\\"odinger solutions for Yukawa and inversely quadratic Yukawa potentials.
YUKAWA POTENTIAL, PANHARMONIC MEASURE AND BROWNIAN MOTION
Sottinen, Tommi
YUKAWA 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 related are replaced with the smooth solutions to the Yukawa equa- tion (1.1) u(x) = Âµ2 u(x), Âµ2 0
Approximate relativistic bound states of a particle in Yukawa field with Coulomb tensor interaction
Sameer M. Ikhdair; Babatunde J. Falaye
2013-07-31
We obtain the approximate relativistic bound state of a spin-1/2 particle in the field of the Yukawa potential and a Coulomb-like tensor interaction with arbitrary spin-orbit coupling number k under the spin and pseudospin (p-spin) symmetries. The asymptotic iteration method is used to obtain energy eigenvalues and corresponding wave functions in their closed forms. Our numerical results show that the tensor interaction removes degeneracies between the spin and p-spin doublets and creates new degenerate doublets for various strengths of tensor coupling.
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…
Ewald sums for Yukawa potentials in quasi-two-dimensional systems
Mazars, Martial
2007-02-07
In this article, the author derive Ewald sums for Yukawa potential for three-dimensional systems with two-dimensional periodicity. This sums are derived from the Ewald sums for Yukawa potentials with three-dimensional periodicity [G. Salin and J.-M. Caillol, J. Chem. Phys.113, 10459 (2000)] by using the method proposed by Parry for the Coulomb interactions [D. E. Parry, Surf. Sci.49, 433 (1975); 54, 195 (1976)].
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.
Martial Mazars
2007-05-29
Yukawa potentials may be long ranged when the Debye screening length is large. In computer simulations, such long ranged potentials have to be taken into account with convenient algorithms to avoid systematic bias in the sampling of the phase space. Recently, we have provided Ewald sums for quasi-two dimensional systems with Yukawa interaction potentials [M. Mazars, {\\it J. Chem. Phys.}, {\\bf 126}, 056101 (2007) and M. Mazars, {\\it Mol. Phys.}, Paper I]. Sometimes, Lekner sums are used as an alternative to Ewald sums for Coulomb systems. In the present work, we derive the Lekner sums for quasi-two dimensional systems with Yukawa interaction potentials and we give some numerical tests for pratical implementations. The main result of this paper is to outline that Lekner sums cannot be considered as an alternative to Ewald sums for Yukawa potentials. As a conclusion to this work : Lekner sums should not be used for quasi-two dimensional systems with Yukawa interaction potentials.
Formation of Coulomb crystal in presence of attractive overlapping Debye sphere potential
Baruah, Swati; Das, Nilakshi
2011-09-15
The role of attractive overlapping Debye sphere (ODS) potential on dust crystal formation has been investigated by using molecular dynamics code. A comparative study on plasma crystal formation has been made between Yukawa and coupled Yukawa-ODS potential by calculating pair-correlation function, for different values of Coulomb coupling parameter {Gamma} and screening parameter {kappa}. From our study, it is seen that the attractive ODS potential becomes dominant beyond a critical radius than that of the Yukawa potential. This leads to the fact that the effect due to combined Yukawa-ODS potential depends more sensitively on {kappa}. From the comparison of the results for Yukawa and ODS potential with experimental results, it is observed that a close agreement is obtained for attractive ODS potential.
Generalized scaling variational method and energy eigenvalues for the Yukawa potential
NASA Astrophysics Data System (ADS)
Gerry, Christopher C.; Laub, Jeffrey
1985-08-01
In a previous paper [Phys. Rev. A 30, 1229 (1984)] we applied the scaling variational method formulated in terms of the SO(2,1) dynamical group to screened Coulomb potentials. Here we generalize that method by scaling a linear combination of SO(2,1) basis states, solving for the eigenvalues by determinant, and minimizing through a search algorithm. The method is applied with high accuracy to the simple Yukawa potential.
Majid Hamzavi; Sameer M. Ikhdair; B. I. Ita
2012-03-30
We approximately solve the Dirac equation for the inversely quadratic Yukawa (IQY) potential including a Coulomb-like tensor potential with arbitrary spin-orbit coupling quantum number . In the framework of the spin and pseudospin (pspin) symmetry, we obtain the energy eigenvalue equation and the corresponding eigenfunctions in closed form by using the Nikiforov-Uvarov method. The numerical results show that the Coulomb-like tensor interaction removes degeneracies between spin and pspin state doublets.
Higher harmonics of the magnetoplasmon in strongly coupled Coulomb and Yukawa systems
Ott, T.; Bonitz, M.; Hartmann, P.; Donko, Z.
2011-04-15
The generation of higher harmonics of the magnetoplasmon frequency which has recently been reported in strongly coupled two-dimensional Yukawa systems is investigated in detail and, in addition, extended to two-dimensional Coulomb systems. We observe higher harmonics over a much larger frequency range than before and compare the theoretical prediction with the simulations. The influence of the coupling, structure, and thermal energy on the excitation of these modes is examined in detail. We also report on the effect of friction on the mode spectra to make predictions about the experimental observability of this new effect.
Structural Phases of Bounded Three-Dimensional Screened Coulomb Clusters (Finite Yukawa System)
K. Qiao; M. Benesh; T. W. Hyde
2006-12-12
The formation of three-dimensional (3D) dust clusters within a complex plasma modeled as a spatially confined Yukawa system is simulated using the box_tree code. Similar to unscreened Coulomb clusters, the occurrence of concentric shells with characteristic occupation numbers was observed. Both the occupation numbers and radii were found to depend on the Debye length. Ground and low energy meta-stable states of the shielded 3D Coulomb clusters were determined for 4
Gauge Orbits and the Coulomb Potential
J. Greensite
2009-03-13
If the color Coulomb potential is confining, then the Coulomb field energy of an isolated color charge is infinite on an infinite lattice, even if the usual UV divergence is lattice regulated. A simple criterion for Coulomb confinement is that the expectation value of timelike link variables vanishes in Coulomb gauge, but it is unclear how this criterion is related to the spectrum of the corresponding Faddeev-Popov operator, which can be used to formulate a quite different criterion for Coulomb confinement. The purpose of this article is to connect the two seemingly different Coulomb confinement criteria, and explain the geometrical basis of the connection.
Martial Mazars
2007-05-25
Yukawa potentials are often used as effective potentials for systems as colloids, plasmas, etc. When the Debye screening length is large, the Yukawa potential tends to the non-screened Coulomb potential ; in this small screening limit, or Coulomb limit, the potential is long ranged. As it is well known in computer simulation, a simple truncation of the long ranged potential and the minimum image convention are insufficient to obtain accurate numerical data on systems. The Ewald method for bulk systems, i.e. with periodic boundary conditions in all three directions of the space, has already been derived for Yukawa potential [cf. Y., Rosenfeld, {\\it Mol. Phys.}, \\bm{88}, 1357, (1996) and G., Salin and J.-M., Caillol, {\\it J. Chem. Phys.}, \\bm{113}, 10459, (2000)], but for systems with partial periodic boundary conditions, the Ewald sums have only recently been obtained [M., Mazars, {\\it J. Chem. Phys.}, {\\bf 126}, 056101 (2007)]. In this paper, we provide a closed derivation of the Ewald sums for Yukawa potentials in systems with periodic boundary conditions in only two directions and for any value of the Debye length. A special attention is paid to the Coulomb limit and its relation with the electroneutrality of systems.
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., E-mail: Sergey.Khrapak@dlr.de [Forschungsgruppe Komplexe Plasmen, Deutsches Zentrum für Luft- und Raumfahrt, Oberpfaffenhofen (Germany)
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)
Density profile of strongly correlated spherical Yukawa plasmas
Bonitz, Michael
Density profile of strongly correlated spherical Yukawa plasmas C. Henning1 , H. Baumgartner1 , A of a 3D one-component Yukawa plasma in an arbitrary confinement potential is derived in mean density of spherical 3D Coulomb [2, 3] and Yukawa [4, 5] crystals 2 Theoretical Model Â· Consider finite
Structural arrest transitions in fluids described by two Yukawa potentials
Jianlan Wu; Yun Liu; Wei-Ren Chen; Jianshu Cao; Sow-Hsin Chen
2004-01-01
We study a model colloidal system where particles interact via short-range attractive and long-range repulsive Yukawa potentials. Using the structure factor calculated from the mean-spherical approximation as the input, the kinetic phase diagrams as functions of the attraction depth and the volume fraction are obtained by calculating the Debye-Waller factors in the framework of the mode-coupling theory for three different
Potential energy landscapes of Th isotopes within the Lublin Strasbourg drop + Yukawa-folded model
Pomorski, Krzysztof
Potential energy landscapes of Th isotopes within the Lublin Strasbourg drop + Yukawa- folded model the Lublin Strasbourg drop + Yukawa-folded model Bozena Nerlo-Pomorska1 , Krzysztof Pomorski1 and Christelle. The macroscopic part of the total energy was derived from the Lublin Strasbourg drop model. The Yukawa
Majid Hamzavi; Sameer M. Ikhdair; M. Solaimani
2012-03-12
We obtain analytical solutions of the two-body spinless Salpeter (SS) equation with Yukawa potential within the conventional approximation scheme to the centrifugal term for any -state. The semi-relativistic bound state energy spectra and the corresponding normalized wave functions are calculated by means of the Nikiforov-Uvarov (NU) method. We also obtain the numerical energy spectrum of the SS equation without any approximation to centrifugal term for the same potential and compare them with the approximated numerical ones obtained from the analytical expressions. It is found that the exact numerical results are in good agreement with the approximated ones for the lower energy states. Special cases are treated like the nonrelativistic limit and the solution for the Coulomb problem.
Three-dimensional stereoscopy of Yukawa (Coulomb) balls in dusty plasmas
Kaeding, Sebastian; Melzer, Andre [Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet Greifswald, 17489 Greifswald (Germany)
2006-09-15
A stereoscopic approach with standard video cameras for positioning and tracking of micrometer sized polymer particles in a radio-frequency gas discharge is presented. The stereoscopy is applied to simultaneously determine the positions of all particles in a three-dimensional strongly coupled spherical dusty plasma (Yukawa ball). The accuracy of the stereoscopic method is discussed. The shell structure and the occupation number of various Yukawa balls are determined and compared to recent simulations and models.
Simplified solution of the Dirac equation with a Coulomb potential
Wong, M.K.F.; Yeh, H.
1982-06-15
It is shown that the Dirac equation with a Coulomb potential has a simplified solution where each component contains one term of a confluent hypergeometric function only instead of two terms. This solution reduces to the usual free-field solution when the Coulomb potential is turned off. Thus the Dirac Coulomb equation has a solution which is not very different from the corresponding Schroedinger or Klein-Gordon equations.
Levin, Yan
Yukawa particles in a confining potential Matheus Girotto, Alexandre P. dos Santos, Thiago Colla (2014) Yukawa particles in a confining potential Matheus Girotto,1,a) Alexandre P. dos Santos,2,3,b of repulsive Yukawa particles confined by an external potential. In the weak coupling limit, we show
Majid Hamzavi; Sameer M. Ikhdair
2012-05-10
The exact Dirac equation for the energy-dependent Coulomb (EDC) potential including a Coulomb-like tensor (CLT) potential has been studied in the presence of spin and pseudospin (p-spin) symmetries with arbitrary spin-orbit quantum number The energy eigenvalues and corresponding eigenfunctions are obtained in the framework of asymptotic iteration method (AIM). Some numerical results are obtained in the presence and absence of EDC and CLT potentials.
NASA Astrophysics Data System (ADS)
Ghazvini, M.; Salehi, N.; Hassanabadi, H.; A. Rajabi, A.
2015-06-01
In this paper, the Schrödinger equation for a 6-body system is studied. We solve this equation for the lithium nucleus by using a supersymmetry method with several specific potentials. These potentials are the Yukawa potential, the generalized Yukawa potential and the Hellmann potential. The results of our model for all calculations show that the ground state binding energy of the lithium nucleus with these potentials is very close to that obtained experimentally.
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.
Kar, Sabyasachi [Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Ho, Y. K. [Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 106 (China)
2009-12-15
We have carried out calculations of multipole polarizabilities of helium and the hydrogen negative ion interacting with pure Coulomb and screened Coulomb potentials using highly accurate correlated exponential wave functions with exponent generated by a quasirandom process. The dipole, quadrupole, and octupole polarizabilities for the ground 1s{sup 2} {sup 1}S{sup e} state for different screening parameters starting from infinity (pure Coulomb case) to small values of the screening parameters, are reported. The octupole polarizability of the hydrogen negative ion is reported for the first time in the literature. The bound 4 {sup 1}F state energy of helium for different screening parameters are also reported.
Visualization of the effective potential and Coulomb correlations in finite metallic systems
Berry, R. Stephen
Visualization of the effective potential and Coulomb correlations in finite metallic systems F June 2002 We present an analytic ansatz to find the effective electrostatic potential and Coulomb findings, particularly on extracting insight regarding the geometric effects of Coulomb correlations
Semiclassical Simulation of Electron Scattering in Attractive Coulomb Potentials
NASA Astrophysics Data System (ADS)
Markmann, Andreas; Graziani, Frank; Batista, Victor; Cimarron Collaboration
2011-10-01
We study the performance of semiclassical dynamics simulations of electron scattering in the Wigner-transform time-dependent picture at few attractive Coulomb potentials and a two-slit potential. Heisenberg uncertainty and interference are compared to exact quantum dynamics. Serious numerical problems typically arise in classical and semiclassical simulations involving Coulomb potentials when particles approach each other and potential gradients (or accelerations) diverge. We introduce an accurate and efficient algorithm for dynamics simulations of particles with attractive potentials developed within the multi-institutional Cimarron Project. Rather than avoiding the singularity problem by using a pseudopotential, the algorithm predicts the outcome of close encounter two-body collisions for the true Coulomb potential by solving the Kepler problem analytically and corrects the trajectory for multiscattering with other particles in the system by using standard numerical techniques (e.g., velocity Verlet, or Gear Predictor corrector algorithms).
Glass-transition properties of Yukawa potentials: from charged point particles to hard spheres.
Yazdi, Anoosheh; Ivlev, Alexei; Khrapak, Sergey; Thomas, Hubertus; Morfill, Gregor E; Löwen, Hartmut; Wysocki, Adam; Sperl, Matthias
2014-06-01
The glass transition is investigated in three dimensions for single and double Yukawa potentials for the full range of control parameters. For vanishing screening parameter, the limit of the one-component plasma is obtained; for large screening parameters and high coupling strengths, the glass-transition properties cross over to the hard-sphere system. Between the two limits, the entire transition diagram can be described by analytical functions. Unlike other potentials, the glass-transition and melting lines for Yukawa potentials are found to follow shifted but otherwise identical curves in control-parameter space. PMID:25019902
Testing Yukawa-like Potentials from f(R)-gravity in Elliptical Galaxies
NASA Astrophysics Data System (ADS)
Napolitano, N. R.; Capozziello, S.; Romanowsky, A. J.; Capaccioli, M.; Tortora, C.
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 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.
Testing Yukawa-like potentials from f(R)-gravity in elliptical galaxies
N. R. Napolitano; S. Capozziello; A. J. Romanowsky; M. Capaccioli; C. Tortora
2012-01-16
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 nebulae data out to 7 Re 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.
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.
Above Threshold Ionization and the Role of the Coulomb Potential
NASA Astrophysics Data System (ADS)
Titi, Atef S.
2011-12-01
Within the single-active-electron approximation (SAE), an ab initio formulation of above threshold ionization (ATI) including rescattering that accounts for the long-range Coulomb potential is presented. From this ab initio formulation, an ad hoc formulation is developed in which the effect of the laser field is to split the atomic potential into two parts: a short range one responsible for rescattering producing the photoelectron high energy plateau, and a long-range Coulomb potential that affects the low energy electrons. Furthermore, the role of the Coulomb potential is investigated by looking at the low energy two dimensional momentum distributions, the momentum distributions along the polarization axis, and the low energy photoelectron energy spectra. Moreover, a formulation that considers the simultaneous transfer of both linear and angular momenta in the ionization process is developed. Finally, a formulation of high harmonic generation (HHG) is presented.
Running Coulomb potential and Lamb shift in QCD
Hoang, Andre H.; Manohar, Aneesh V.; Stewart, Iain W.
2001-07-01
The QCD {beta} function and the anomalous dimensions for the Coulomb potential and the static potential first differ at three loop order. We evaluate the three loop ultrasoft anomalous dimension for the Coulomb potential and give the complete three loop running. Using this result, we calculate the leading logarithmic Lamb shift for a heavy-quark{endash}antiquark bound state, which includes all contributions to the binding energies of the form m{alpha}{sub s}{sup 4}({alpha}{sub s}ln{alpha}{sub s}){sup k}, k{ge}0.
Spinless particles in the field of unequal Scalar-Vector Yukawa potentials
Hamzavi, Majid; Thylwe, Karl-Erik
2013-01-01
We present analytical bound state solutions of the spin-zero Klein-Gordon (KG) particles in the field of unequal mixture of scalar and vector Yukawa potentials within the framework of the approximation scheme to the centrifugal potential term for any arbitrary -state. The approximate energy eigenvalues and unnormalized wave functions are obtained in closed forms using a simple shortcut of the Nikiforov-Uvarov (NU) method. Further, we solve the KG-Yukawa problem for its exact numerical energy eigenvalues via amplitude phase (AP) method to test the accuracy of the present solutions found by using the NU method. Our numerical tests using energy calculations demonstrate the existence of inter-dimensional degeneracy amongst energy states of the KG-Yukawa problem. The dependence of the energy on the dimension is numerically discussed for spatial dimensions
Spinless particles in the field of unequal Scalar-Vector Yukawa potentials
Majid Hamzavi; Sameer M. Ikhdair; Karl-Erik Thylwe
2013-07-31
We present analytical bound state solutions of the spin-zero Klein-Gordon (KG) particles in the field of unequal mixture of scalar and vector Yukawa potentials within the framework of the approximation scheme to the centrifugal potential term for any arbitrary -state. The approximate energy eigenvalues and unnormalized wave functions are obtained in closed forms using a simple shortcut of the Nikiforov-Uvarov (NU) method. Further, we solve the KG-Yukawa problem for its exact numerical energy eigenvalues via amplitude phase (AP) method to test the accuracy of the present solutions found by using the NU method. Our numerical tests using energy calculations demonstrate the existence of inter-dimensional degeneracy amongst energy states of the KG-Yukawa problem. The dependence of the energy on the dimension is numerically discussed for spatial dimensions
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.
Steven Kenneth Kauffmann
2010-05-06
For Abelian gauge theory a properly relativistic gauge is developed by supplementing the Lorentz condition with causal determination of the time component of the four-vector potential by retarded Coulomb transformation of the charge density. This causal Lorentz gauge agrees with the Coulomb gauge for static charge densities, but allows the four-vector potential to have a longitudinal component that is determined by the time derivative of the four-vector potential's time component. Just as in Coulomb gauge, the two transverse components of the four-vector potential are its sole dynamical part. The four-vector potential in this gauge covariantly separates into a dynamical transverse four-vector potential and a nondynamical timelike/longitudinal four-vector potential, where each of these two satisfies the Lorentz condition. In fact, analogous partition of the conserved four-current shows each to satisfy a Lorentz-condition Maxwell equation system with its own conserved four-current. Because of this complete separation, either of these four-vector potentials can be tinkered with without affecting its counterpart. Since it satisfies the Lorentz condition, the nondynamical four-vector potential times a constant with dimension of inverse length squared is itself a conserved four-current, and so can be fed back into its own source current, which transforms its time component into an extended Yukawa, with both exponentially decaying and exponentially growing components. The latter might be the mechanism of quark-gluon confinement: in non-Abelian color gauge theory the Yukawa mixture ratio ought to be tied to color, with palpable consequences for "colorful" hot quark-gluon plasmas.
Stark resonances of the Yukawa potential: Energies and widths, crossings and avoided crossings
Pawlak, Mariusz; Bylicki, Miroslaw
2011-02-15
The resonance energy spectrum of a system interacting with the Yukawa potential and embedded in an external homogeneous and static electric field is investigated. The positions and widths of levels have been computed by using the complex coordinate rotation method. Interesting avoided-crossing and crossing effects appear.
Bound energy for the exponential-cosine-screened Coulomb potential
Sameer M. Ikhdair; Ramazan Sever
2006-04-11
An alternative approximation scheme has been used in solving the Schrodinger equation for the exponential-cosine-screened Coulomb potential. The bound state energ\\i es for various eigenstates and the corresponding wave functions are obtained analytically up to the second perturbation term.
Analytic phase shifts for truncated and screened Coulomb potentials
NASA Astrophysics Data System (ADS)
Patil, S. H.
1981-12-01
For a special class of truncated and screened Coulomb potentials, some analyticity properties of the phase shifts are deduced as functions of ?, the truncation and screening parameter. Use of these properties and scale transformations leads to analytic expressions for the phase shifts, which are valid in the region of small ?.
Classical and quantum scattering by a Coulomb potential
A. I. Nikishov
2008-04-14
For relativistic energies the small angle classical cross section for scattering on a Coulomb potential agrees with the first Born approximation for quantum cross section for scalar particle only in the leading term. The disagreement in other terms can be avoided if the sum of all corrections to the first Born approximation for large enough Coulomb charge contain the classical terms which are independent of that charge. A small part of the difference in classical and quantum cross sections may be attributed to the fact that the relativistic quantum particle can rush through the field without interaction. We expect that smaller impact parameters and spin facilitate this affect.
Regularized semiclassical radial propagator for the Coulomb potential
NASA Astrophysics Data System (ADS)
Manning, Robert S.; Ezra, Gregory S.
1994-08-01
We derive a regularized semiclassical radial propagator for the Coulomb potential, a case for which standard approaches run into well-known difficulties associated with a non-Cartesian radial coordinate and a potential singularity. Following Kleinert [Path Integrals in Quantum Mechanics, Statistics and Polymer Physics (World Scientific, Singapore, 1990)], we first perform a quantum-mechanical regularization of the propagator. The semiclassical limit is then obtained by stationary phase approximation of the resulting integrals. The semiclassical propagator so derived has the standard Van Vleck-Gutzwiller form for the radial Coulomb problem with a potential correction (Langer modification) term included. The regularized semiclassical propagator is applied to compute the autocorrelation function for a Gaussian Rydberg wave packet.
Bound states of a more general exponential screened Coulomb potential
Sameer M. Ikhdair; Ramazan Sever
2006-04-11
An alternative approximation scheme has been used in solving the Schrodinger equation to the more general case of exponential screened Coulomb potential, V(r)=-(a/r)\\[1+(1+br)e^{-2br}]. The bound state energies of the 1s, $2s, and 3s-states, together with the ground state wave function are obtained analytically upto the second perturbation term.
Ribas, M O; Devecchi, F P; Kremer, G M
2015-01-01
In this work we investigate a model for the early Universe in a Bianchi type-I metric, where the sources of the gravitational field are a fermionic and a bosonic field, interacting through a Yukawa potential, following the standard model of elementary particles. It is shown that the fermionic field has a negative pressure, while the boson has a small positive pressure. The fermionic field is the responsible for an accelerated regime at early times, but since the total pressure tends to zero for large times, a transition to a decelerated regime occurs. Here the Yukawa potential answers for the duration of the accelerated regime, since by decreasing the value of its coupling constant the transition accelerated-decelerated occurs in later times. The isotropization which occurs for late times is due to the presence of the fermionic field as one of the sources of the gravitational field.
NASA Astrophysics Data System (ADS)
Ribas, M. O.; Samojeden, L. L.; Devecchi, F. P.; Kremer, G. M.
2015-10-01
In this work we investigate a model for the early Universe in a Bianchi type-I metric, where the sources of the gravitational field are a fermionic and a bosonic field, interacting through a Yukawa potential, following the standard model of elementary particles. It is shown that the fermionic field has a negative pressure, while the boson has a small positive pressure. The fermionic field is the responsible for an accelerated regime at early times, but since the total pressure tends to zero for large times, a transition to a decelerated regime occurs. Here the Yukawa potential answers for the duration of the accelerated regime, since by decreasing the value of its coupling constant the transition accelerated–decelerated occurs in later times. The isotropization which occurs for late times is due to the presence of the fermionic field as one of the sources of the gravitational field.
M. O. Ribas; L. L. Samojeden; F. P. Devecchi; G. M. Kremer
2015-10-05
In this work we investigate a model for the early Universe in a Bianchi type-I metric, where the sources of the gravitational field are a fermionic and a bosonic field, interacting through a Yukawa potential, following the standard model of elementary particles. It is shown that the fermionic field has a negative pressure, while the boson has a small positive pressure. The fermionic field is the responsible for an accelerated regime at early times, but since the total pressure tends to zero for large times, a transition to a decelerated regime occurs. Here the Yukawa potential answers for the duration of the accelerated regime, since by decreasing the value of its coupling constant the transition accelerated-decelerated occurs in later times. The isotropization which occurs for late times is due to the presence of the fermionic field as one of the sources of the gravitational field.
Spectra generated by a confined softcore Coulomb potential
NASA Astrophysics Data System (ADS)
Hall, Richard L.; Saad, Nasser
2014-08-01
Analytic and approximate solutions for the energy eigenvalues generated by a confined softcore Coulomb potentials of the form a/(r + ?) in d > 1 dimensions are constructed. The confinement is effected by linear and harmonic-oscillator potential terms, and also through "hard confinement" by means of an impenetrable spherical box. A byproduct of this work is the construction of polynomial solutions for a number of linear differential equations with polynomial coefficients, along with the necessary and sufficient conditions for the existence of such solutions. Very accurate approximate solutions for the general problem with arbitrary potential parameters are found by use of the asymptotic iteration method.
Reduced form for Coulomb-wave multicenter integrals
Straton, J.C. )
1990-07-01
In a previous paper (J. C. Straton, Phys. Rev. A 41, 71 (1990)) an integro-differential transform was introduced and utilized to obtain the analytically reduced form for multicenter integrals composed of general-state hydrogenic orbitals, Yukawa or Coulomb potentials, and plane waves. The present paper extends this result to include Coulomb waves.
Coulomb Impurity Potential RbCl Quantum Pseudodot Qubit
NASA Astrophysics Data System (ADS)
Ma, Xin-Jun; Qi, Bin; Xiao, Jing-Lin
2015-08-01
By employing a variational method of Pekar type, we study the eigenenergies and the corresponding eigenfunctions of the ground and the first-excited states of an electron strongly coupled to electron-LO in a RbCl quantum pseudodot (QPD) with a hydrogen-like impurity at the center. This QPD system may be used as a two-level quantum qubit. The expressions of electron's probability density versus time and the coordinates, and the oscillating period versus the Coulombic impurity potential and the polaron radius have been derived. The investigated results indicate ? that the probability density of the electron oscillates in the QPD with a certain oscillating period of , ? that due to the presence of the asymmetrical potential in the z direction of the RbCl QPD, the electron probability density shows double-peak configuration, whereas there is only one peak if the confinement is a two-dimensional symmetric structure in the xy plane of the QPD, ? that the oscillation period is a decreasing function of the Coulombic impurity potential, whereas it is an increasing one of the polaron radius.
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
Effect of wake potential on Coulomb crystallization in the presence of magnetic field
Bhattacharjee, Saurav; Das, Nilakshi
2012-10-15
The formation of dust crystal in plasma under the influence of repulsive Yukawa (Debye-Hueckel) potential is a well known phenomenon. The regular structure of dust particles is affected by anisotropic ion flow near the sheath region. The bombardment of the ions over dust grains distorts their Debye sphere by overshielding the dust cloud and gives rise to an attractive oscillatory wake potential. In this paper, we have obtained an expression for wake potential along with the Yukawa type of potential in a complex plasma in the presence of magnetic field, for subsonic ion flow towards the plasma sheath. In the presence of magnetic field, interaction potential gets modified and becomes anisotropic. We have studied the combined effect of the attractive wake potential as well as repulsive Yukawa potential on a 2D dust crystal, both in the presence and absence of magnetic field, using molecular dynamic simulation.
Highly accurate eigenvalues for the distorted Coulomb potential
NASA Astrophysics Data System (ADS)
Ixaru, L. Gr.; de Meyer, H.; vanden Berghe, G.
2000-03-01
We consider the eigenvalue problem for the radial Schrödinger equation with potentials of the form V(r)=S(r)/r+R(r) where S(r) and R(r) are well behaved functions which tend to some (not necessarily equal) constants when r-->0 and r-->?. Formulas (14.4.5)-(14.4.8) of Abramowitz and Stegun [Handbook of Mathematical Functions, 8th ed. (Dover, New York, 1972)], corresponding to the pure Coulomb case, are here generalized for this distorted case. We also present a complete procedure for the numerical solution of the problem. Our procedure is robust, very economic and particularly suited for very large n. Numerical illustrations for n up to 2000 are given.
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.
Screening in Yukawa fluid mixtures
A. J. Archer; P. Hopkins; R. Evans
2006-06-28
The effective pair potential between mesoscopic charged particles in a neutralising background medium takes a Yukawa form $\\exp(-\\lambda r)/r$ with screening length $\\lambda^{-1}$. We consider a dilute suspension of such Yukawa particles dispersed in a solvent with correlation length $\\xiYukawa interaction is `screened' if the pair potentials between solvent particles exhibit Yukawa decay with the same screening length $\\lambda^{-1}$. However, if the solvent pair potentials are shorter ranged than the solute Yukawa potentials, then the effective potential between pairs of solute particles is `unscreened', i.e. the effective potential between the solute particles is equal to the bare potential at large particle separations.
Propagation of gravitational waves from slow motion sources in a Coulomb type potential
Hideki Asada; Toshifumi Futamase
1997-11-05
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.
NASA Astrophysics Data System (ADS)
Arda, Altu?; Sever, Ramazan
2015-06-01
The Schrödinger-like equation written in terms of the displacement operator is solved analytically for a inverse square plus Coulomb-like potential. Starting from the new Hamiltonian, the effects of the spatially dependent mass on the bound states and normalized wave functions of the "usual" inverse square plus Coulomb interaction are discussed.
Additional {alpha}-particle optical potential tests below the Coulomb barrier
Avrigeanu, M.; Avrigeanu, V.
2010-03-15
New results of ({alpha},{gamma}) and ({alpha},n) reaction cross section measurements close to the reaction thresholds support the setting up of recent parameters of the {alpha}-particle optical model potential (OMP) below the Coulomb barrier. Particular features of the {alpha}-particle optical potential at energies below the Coulomb barrier explain the failure of using the OMP parameters obtained by analysis of only {alpha}-particle elastic scattering at higher energies.
Miroslav Sukenik; Jozef Sima
2003-04-02
Model of Expansive Nondecelerative Universe (ENU) due to involving Vaidya metric makes it possible to localize the energy density of gravitational field. This its capability allows for answering several open questions and supporting (or contradicting) results obtained using different theoretical approaches. This paper is aimed to contributing to a solution of some cosmological problems, in particular those linked to the Yukawa potential consequences, independent way of dark matter estimation, ionospheric F2 layer behaviour, and cyclotron radiation.
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.
Sameer M. Ikhdair; Ramazan Sever
2010-03-25
We solve the Dirac equation approximately for the attractive scalar $S(r)$ and repulsive vector $V(r)$ Hulth\\'{e}n potentials including a Coulomb-like tensor potential with arbitrary spin-orbit coupling quantum number $\\kappa .$ In the framework of the spin and pseudospin symmetric concept, we obtain the analytic energy spectrum and the corresponding two-component upper- and lower-spinors of the two Dirac particles by means of the Nikiforov-Uvarov method in closed form. The limit of zero tensor coupling and the non-relativistic solution are obtained. The energy spectrum for various levels is presented for several $\\kappa $ values under the condition of exact spin symmetry in the presence or absence of tensor coupling.
Majid Hamzavi; Sameer M. Ikhdair
2012-07-03
The usual approximation scheme is used to study the solution of the Duffin-Kemmer-Petiau (DKP) equation for a vector Yukawa potential in the framework of the parametric Nikiforov-Uvarov (NU) method. The approximate energy eigenvalue equation and the corresponding wave function spinor components are calculated for arbitrary total angular momentum in closed form. Further, the approximate energy equation and wave function spinor components are also given for case. A set of parameter values is used to obtain the numerical values for the energy states with various values of quantum levels
Exchange-coulomb potential energy curves for He-He, and related physical properties
Ronald A. Aziz; M. J. Slaman; A. Koide; A. R. Allnatt; William J. Meath
1992-01-01
The investigation of the reliability of the original simple overall damped form of the XC (exchange-Coulomb) potential is extended to the He-He interaction, and a new multidamped version of the XC potential is introduced. New one and two parameter overall damped, and one and two parameter multidamped XC potentials for He-He are constructed. The results obtained from these potentials for
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.
Exchange-Coulomb potential energy surfaces and related physical properties for Ne-N2
Ashok K. Dham; William J. Meath
2001-01-01
An exchange-Coulomb (XC) potential energy model is developed for the Ne-N2 interaction. The construction of this new potential energy surface is based on recent results for the Heitler-London interaction energy, the long range dispersion energies, and the microwave spectra of the dimer. The adjustable parameters in the final XC1 potential energy surface have been determined by fitting the frequencies of
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.
A perturbative treatment for the exponential-cosine-screened Coulomb potential
Sameer M. Ikhdair
2005-09-01
An alternative approximation scheme has been used in solving the Schroedinger equation for the exponential-cosine-screened Coulomb potential. The bound state energies for various eigenstates and the corresponding wave functions are obtained analytically up to the second perturbation term.
Hidden-sector correction to Coulomb potential through the photonic portal
Wojciech Krolikowski
2011-01-03
We show that in the model of hidden sector of the Universe, interacting with the Standard-Model sector through the photonic portal, the Standard-Model Coulomb potential gets a tiny hidden-sector additive correction that might turn out to be either exciting or fatal for the verification of this model.
Energy dependence of nucleus-nucleus potential close to the Coulomb barrier
Kouhei Washiyama; Denis Lacroix
2008-08-12
The nucleus-nucleus interaction potentials in heavy-ion fusion reactions are extracted from the microscopic time-dependent Hartree-Fock theory for mass symmetric reactions $^{16}$O${}+^{16}$O, $^{40}$Ca${}+^{40}$Ca, $^{48}$Ca${}+^{48}$Ca and mass asymmetric reactions $^{16}$O$ +^{40,48}$Ca, $^{40}$Ca${}+^{48}$Ca, $^{16}$O+$^{208}$Pb, $^{40}$Ca+$^{90}$Zr. When the center-of-mass energy is much higher than the Coulomb barrier energy, potentials deduced with the microscopic theory identify with the frozen density approximation. As the center-of-mass energy decreases and approaches the Coulomb barrier, potentials become energy dependent. This dependence signs dynamical reorganization of internal degrees of freedom and leads to a reduction of the "apparent" barrier felt by the two nuclei during fusion of the order of $2-3 %$ compared to the frozen density case. Several examples illustrate that the potential landscape changes rapidly when the center-of-mass energy is in the vicinity of the Coulomb barrier energy. The energy dependence is expected to have a significant role on fusion around the Coulomb barrier.
The Klein-Gordon Equation for the Coulomb Potential in Non-commutative Space
Amin Rezaei Akbarieh; Hossein Motavalli
2009-11-25
In this paper the stationary Klein-Gordon equation is considered for the Coulomb potential in non-commutative space. The energy shift due to noncommutativeity is obtained via the perturbation theory. Furthermore, we show that the degeneracy of the initial spectral line is broken in transition from commutative space to non-commutative space.
Potential splitting approach to the three-body Coulomb scattering problem
NASA Astrophysics Data System (ADS)
Volkov, M. V.; Yarevsky, E. A.; Yakovlev, S. L.
2015-05-01
The potential splitting technique is developed for solving the three-body Coulomb scattering problem. The formalism is applied to e+-H and e+-He+ scattering problems. Calculated phase shifts and the annihilation rate parameter Z\\text{eff} are in fairly good agreement with the most accurate results available in the literature.
Virial theorem and Gibbs thermodynamic potential for Coulomb systems
Bobrov, V. B., E-mail: vic5907@mail.ru, E-mail: satron@mail.ru [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya St. 13, Bd. 2, Moscow 125412 (Russian Federation); National Research University “MPEI,” Krasnokazarmennaya str. 14, Moscow 111250 (Russian Federation); Trigger, S. A., E-mail: vic5907@mail.ru, E-mail: satron@mail.ru [Joint Institute for High Temperatures, Russian Academy of Sciences, Izhorskaya St. 13, Bd. 2, Moscow 125412 (Russian Federation); Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, Berlin D-12489 (Germany)
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.
NASA Astrophysics Data System (ADS)
Kumari, Raj
2015-05-01
We discuss the effect of adding deformation in the Coulomb potential in the fusion process using well tested proximity based nuclear potentials. This effect is analyzed at different orientations of the two colliding nuclei. Our study reveals that different (oblate/prolate) quadruple deformations in the Coulomb potential affect the total interaction potential in the inner region in different manner. In addition to nature of deformation (oblate/prolate), the depth of the fusion pocket also varies with change in orientations of colliding nuclei. A totally opposite trend of variation is observed in case of spherical-oblate and oblate-oblate systems as compared to spherical-prolate and prolate-prolate systems.
Zero-temperature phase diagram of Yukawa bosons
NASA Astrophysics Data System (ADS)
Osychenko, O. N.; Astrakharchik, G. E.; Mazzanti, F.; Boronat, J.
2012-06-01
We study the zero-temperature phase diagram of bosons interacting via screened Coulomb (Yukawa) potential by means of the diffusion Monte Carlo method. The Yukawa potential is used as a model interaction in the neutron matter, dusty plasmas, and charged colloids. As shown by Petrov [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.99.130407 99, 130407 (2007)], interactions between weakly bound molecules of heavy and light fermionic atoms are described by an effective Yukawa potential with a strength related to the heavy-light mass ratio M/m, which might lead to crystallization in a two-dimensional geometry if the mass ratio of heavy-light fermions exceeds a certain critical value. In the present work we do a thorough study of the quantum three-dimensional Yukawa system. For strong interactions (equivalently, large mass ratios) the system experiences several phase transitions as the density is increased, passing from gas to solid and to gas phase again. Weakly interacting Yukawa particles do not crystallize at any density. We find the minimal interaction strength at which the crystallization happens. In terms of the two-component fermionic system, this strength corresponds to a heavy-light mass ratio of M/m˜180, so that it is impossible to realize the gas-crystal transition in a conventional bulk system. For the Yukawa model of fermionic mixtures we also analyze the possibility of building molecular systems with very large effective mass ratios by confining the heavy component to a sufficiently deep optical lattice. We show how the effective mass of the heavy component can be made arbitrarily large by increasing the lattice depth, thus leading to a tunable effective mass ratio that can be used to realize a molecular superlattice.
Volkov, M. V. [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden); Department of Quantum Mechanics, St. Petersburg State University, RU-198504 St Petersburg (Russian Federation); Yakovlev, S. L.; Yarevsky, E. A. [Department of Computational Physics, St. Petersburg State University, RU-198504 St Petersburg (Russian Federation); Elander, N. [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden)
2011-03-15
In this paper we suggest an approach for the multichannel Coulomb scattering problem. The Schroedinger equation for the problem is reformulated in the form of a set of inhomogeneous equations with a finite-range driving term. The boundary conditions at infinity for this set of equations have been proven to be purely outgoing waves. The formulation presented here is based on splitting the interaction potential into a finite-range core part and a long-range tail part. The conventional matching procedure coupled with the integral Lippmann-Schwinger equations technique is used in the formal theoretical basis of this approach. The reformulated scattering problem is suitable for application in the exterior complex scaling technique: the practical advantage is that after complex scaling, the problem is reduced to a boundary problem with zero boundary conditions. The Coulomb wave functions are used only at a single point; if this point is chosen to be at a sufficiently large distance, on using the asymptotic expansion of Coulomb functions, one may completely avoid the Coulomb functions in the calculations. The theoretical results are illustrated with numerical calculations for two models.
NASA Astrophysics Data System (ADS)
Bose, Subir K.; Schulze-Halberg, Axel
We improve a result obtained in Ref. 2: In the context of supersymmetric quantum mechanics we present a certain superpotential that yields a trial function we use for the calculation of variational quantum bound state energies of the screened Coulomb potential. We show that for small screening parameters our trial function yields better approximations for the energies than the trial function used in Ref. 2.
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.
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.
Treatment of the two-body Coulomb problem as a short-range potential
Gasaneo, G.; Ancarani, L. U.
2009-12-15
The scattering wave function and the transition amplitude for the two-body Coulomb problem are written as power series of the Sommerfeld parameter. Making use of a mathematical study of the nth derivatives of Kummer function with respect to its first parameter, the series coefficients are expressed analytically in terms of multivariable hypergeometric functions. We establish the connection with the Born series based on the free particle Green's function and show its applicability to long-range potentials. We also relate our analysis to recent works on the distorted-wave theory for the Coulomb problem. For the transition amplitude, the Born series is presented and compared to the series obtained from the exact well-known Rutherford result. Since the two series differ, care must be taken when extracting the relevant information about the scattering. Finally, implications for three-body problems are discussed.
General Pade Effective Potential for Coulomb Problems in Condensed and Soft Matters
NASA Astrophysics Data System (ADS)
Quyen, B. L.; Mai, D. N.; Hoa, N. M.; Van, T. T. T.; Hoai, N. L.; Viet, N. A.
2014-09-01
Effective potentials for finding the ground states and physical configurations have essential meaning in many Coulomb problems of condensed and soft matters. The ordinary n-Pade approximation potentials define as the ratio of Pi(r)/Pi+1(r), where Pi(r) are the polynomials of i-th order of charge separation r, give quite good fit and agreement of calculation results and experimental data for Coulomb problems, where screening effects are not important or exchange photons still are massless. In this work we consider a general Pade effective potential by included a factor of exponential form, which could give more accurate results also for above mentioned cases. This general Pade effective potentials with analytical expressions were useful to perform analytical calculations, estimations and to reduce the amount of computational time for future investigations in condensed and soft matter topics. For example of soft matter problems, we study the case of MS2 virus, the general Pade potential gives much more correct results comparing with ordinary Pade approximation.
Exact photoionization and radiative recombination cross section in a Coulomb potential
NASA Astrophysics Data System (ADS)
Clauser, C. F.; Barrachina, R. O.
2015-01-01
In this work, we analytically evaluate the exact matrix element for a non-relativistic Continuum-Bound radiative transition in a Coulomb potential. We apply this result to the photoionization (and radiative recombination) process, and calculate the total cross sections giving an analytical expression for the transition from the ground state. To our best knowledge the exact solution to this problem has never been addressed even though the analytical calculation is quite simple, and the final result is not more complicated than any of its approximations. We compare our result with the well-known plane wave and Coulombian dipolar approximations, in a wide range of energies.
Transport properties of quasi-two-dimensional dissipative systems with a screened Coulomb potential
NASA Astrophysics Data System (ADS)
Vaulina, O. S.; Dranzhevski?, I. E.
2007-06-01
Results are presented from numerical investigations of the dynamics of quasi-two-dimensional systems in the form of a monolayer of dust grains interacting by means of a screened Coulomb potential and suspended in the Earth’s gravitational field by an external electric field. The structural and transport characteristics of such a system, including the pair correlation functions and the viscosity and diffusion coefficients, were investigated over a broad parameter range corresponding to the conditions under which dust structures are observed in RF capacitive discharge plasmas. An analysis of the results obtained revealed that there is a specific topological transition typical of systems having a low spatial dimension.
Polarizabilities of two-electron positive ions with screened Coulomb potentials
Jiang Zishi; Kar, Sabyasachi [Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Ho, Y. K. [Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 106 (China)
2011-07-15
We have carried out calculations of the polarizabilities of the two-electron positive ions Li{sup +}, Be{sup 2+}, B{sup 3+}, C{sup 4+}, N{sup 5+}, and O{sup 6+} interacting with screened Coulomb potentials. Highly accurate correlated exponential wave functions are used to represent correlation effects on the charged particles. The dipole, quadrupole, and octupole polarizabilities for the screening parameters in the range 0-1a{sub 0}{sup -1} are reported. Reported results for the unscreened case are comparable with the available results and for the screened case show some interesting behavior with increasing nuclear charge.
NASA Astrophysics Data System (ADS)
Bykov, V. P.; Gerasimov, A. V.
1992-08-01
A new variational method without a basis set for calculation of the eigenvalues and eigenfunctions of Hamiltonians is suggested. The expansion of this method for the Coulomb potentials is given. Calculation of the energy and charge distribution in the two-electron system for different values of the nuclear charge Z is made. It is shown that at small Z the Coulomb forces disintegrate the electron cloud into two clots.
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
Berry, R. Stephen
Range effects of the Coulombic forces on structures, thermodynamic properties and potential energy of potential energy surfaces Dynamical and thermodynamical behavior a b s t r a c t By introducing two, thermodynamic properties and the potential energy landscapes of binary ionically bonded systems as illustrated
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.
Fluid modes of a spherically confined Yukawa plasma.
Kählert, H; Bonitz, M
2010-09-01
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 ?=?R , where R is the plasma radius and ? is the inverse screening length. The eigenfrequencies increase monotonically with ? and saturate in the limit ??? . Compared with the results in the Coulomb limit [D. H. E. Dubin, Phys. Rev. Lett. 66, 2076 (1991)10.1103/PhysRevLett.66.2076], 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. PMID:21230196
Sameer M. Ikhdair
2009-03-23
We study the effect of spatially dependent mass functions over the solution of the Klein-Gordon equation in the (3+1)-dimensions for spinless bosonic particles where the mixed scalar-vector Coulomb-like field potentials and masses are directly proportional and inversely proportional to the distance from force center. The exact bound state energy eigenvalues and the corresponding wave functions of the Klein-Gordon equation for mixed scalar-vector and pure scalar Coulomb-like field potentials are obtained by means of the Nikiforov-Uvarov (NU) method. The energy spectrum is discussed for different scalar-vector potential mixing cases and also for constant mass case.
Approximate k-state solutions to the Dirac-Yukawa problem based on the spin and pseudospin symmetry
Sameer M. Ikhdair
2012-03-09
Using an approximation scheme to deal with the centrifugal (pseudo-centrifugal) term, we solve the Dirac equation with the screened Coulomb (Yukawa) potential for any arbitrary spin-orbit quantum number {\\kappa}. Based on the spin and pseudospin symmetry, analytic bound state energy spectrum formulas and their corresponding upper- and lower-spinor components of two Dirac particles are obtained using a shortcut of the Nikiforov-Uvarov method. We find a wide range of permissible values for the spin symmetry constant C_{s} from the valence energy spectrum of particle and also for pseudospin symmetry constant C_{ps} from the hole energy spectrum of antiparticle. Further, we show that the present potential interaction becomes less (more) attractive for a long (short) range screening parameter {\\alpha}. To remove the degeneracies in energy levels we consider the spin and pseudospin solution of Dirac equation for Yukawa potential plus a centrifugal-like term. A few special cases such as the exact spin (pseudospin) symmetry Dirac-Yukawa, the Yukawa plus centrifugal-like potentials, the limit when {\\alpha} becomes zero (Coulomb potential field) and the non-relativistic limit of our solution are studied. The nonrelativistic solutions are compared with those obtained by other methods.
Volkov, M V; Yarevsky, E A; Elander, N
2011-01-01
In this paper we suggest a new approach for the multichannel Coulomb scattering problem. The Schr\\"{o}dinger equation for the problem is reformulated in the form of a set of inhomogeneous equations with a finite-range driving term. The boundary conditions at infinity for this set of equations have been proven to be purely outgoing waves. The formulation {presented here} is based on splitting the interaction potential into a finite range core part and a long range tail part. The conventional matching procedure coupled with the integral Lippmann-Schwinger equations technique are used in the formal theoretical basis of this approach. The reformulated scattering problem is suitable for application in the exterior complex scaling technique: the practical advantage is that after the complex scaling the problem is reduced to a boundary problem with zero boundary conditions. The Coulomb wave functions are used only at a single point: if this point is chosen to be at a sufficiently large distance, on using the asympto...
Energies and wave functions for a soft-core Coulomb potential
NASA Astrophysics Data System (ADS)
Hall, Richard L.; Saad, Nasser; Sen, K. D.; Ciftci, Hakan
2009-09-01
For the family of model soft-core Coulomb potentials represented by V(r)=-[Z/(rq+?q)1/q] , with the parameters Z>0,?>0,q?1 , it is shown analytically that the potentials and eigenvalues, E?? , are monotonic in each parameter. The potential envelope method is applied to obtain approximate analytic estimates in terms of the known exact spectra for pure power potentials. For the case q=1 , the asymptotic iteration method is used to find exact analytic results for the eigenvalues E?? and corresponding wave functions, expressed in terms of Z and ? . A proof is presented establishing the general concavity of the scaled electron density near the nucleus resulting from the truncated potentials for all q . Based on an analysis of extensive numerical calculations, it is conjectured that the crossing between the pair of states [(?,?),(?',?')] is given by the conditions ?'?(?+1) and ?'?(?+3) . The significance of these results for the interaction of intense laser field with an atom is pointed out. Differences in the observed level-crossing effects between the soft-core potentials and the hydrogen atom confined inside an impenetrable sphere are discussed.
Coulomb explosion potential sputtering induced by slow highly charged ion impact
NASA Astrophysics Data System (ADS)
Tona, Masahide; Takahashi, Satoshi; Nagata, Kazuo; Yoshiyasu, Nobuo; Yamada, Chikashi; Nakamura, Nobuyuki; Ohtani, Shunsuke; Sakurai, Makoto
2005-11-01
We have observed secondary ion emission from a hydrogen-terminated Si(111) 1×1 surface and a native SiO2 thin film on the Si substrate (SiO2/Si) irradiated with slow (vion
Coulomb explosion potential sputtering induced by slow highly charged ion impact
Tona, Masahide; Takahashi, Satoshi; Nagata, Kazuo; Yoshiyasu, Nobuo; Yamada, Chikashi; Nakamura, Nobuyuki; Ohtani, Shunsuke; Sakurai, Makoto
2005-11-28
We have observed secondary ion emission from a hydrogen-terminated Si(111) 1x1 surface and a native SiO{sub 2} thin film on the Si substrate (SiO{sub 2}/Si) irradiated with slow (v{sub ion}
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.
Borowska, L.; Terenetsky, K.; Verbitsky, V.; Fritzsche, S.
2009-04-15
An analytical expression for the dynamic polarization potential is derived for the elastic scattering of light halo nuclei in the Coulomb field of heavy targets. The derivation is based on the adiabatic motion of the projectile below and close to the Coulomb barrier together with a uniform approximation for the Coulomb functions. Detailed computations have been carried out for the elastic scattering of d+{sup 208}Pb and {sup 6}He+{sup 208}Pb at collision energies of 8 and 17.8 MeV and are compared with measurements as far as available. The obtained expression for the dynamic polarization potential is simple and can be applied for any arbitrary system with a dineutron configuration.
G. Van Hooydonk
2005-10-12
Comparing observed and theoretical potential energy curves for natural and exotic neutral 4-unit charge Coulomb systems like HH and HantiH leads to new conclusions on the effect of charge-antisymmetry in nature. With singularities in the HantiH PEC as found by Aldrovandi and Puget and by Junker and Bardsley, any cusp in the HantiH PEC significantly affects the annihilation cross section. This problem for the HantiH interaction generated many new wave mechanical calculations mainly to remove annoying cusps. We review all available PECs for 4-unit charge systems and find that corrections for the Morgan-Hughes HantiH PEC can either go to the repulsive side (to the conventionally expected annihilation channel) or to the opposite attractive side (to the attractive branch of the observed PEC of natural molecular HH). We observe that all theoretical HantiH PECs published thus far would intersect the observed PEC of natural HH. This is, however, impossible with the non-crossing rule. A classical ab initio calculation of the electrostatic perturbation brings the HantiH PEC much closer to the observed HH PEC than to the PEC of the annihilative channel. This new unprecedented result for long-range behavior in 4-unit charge Coulomb systems confirms that natural antiH must exist and that molecule HH must be interpreted as HantiH. In fact, this seems to be the only solution left, if PECs for systems HH and HantiH with the same symmetry cannot cross.
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.
Rajeev, S.G. [Department of Physics and Astronomy, University of Rochester, Rochester, NY14627 (United States)], E-mail: rajeev@pas.rochester.edu
2008-11-15
We solve exactly the classical non-relativistic Landau-Lifshitz equations of motion for a charged particle moving in a Coulomb potential, including radiation damping. The general solution involves the Painleve transcendent of type II. It confirms our physical intuition that a negatively charged classical particle will spiral into the nucleus, supporting the validity of the Landau-Lifshitz equation.
NASA Astrophysics Data System (ADS)
Ma, Qian; Dai, Jiayu; Kang, Dongdong; Zhao, Zengxiu; Yuan, Jianmin; Zhao, Xueqing
2014-12-01
Molecular dynamics (MD) simulations are performed to investigate the temperature relaxation between electrons and ions in a fully ionized, dense hydrogen plasma. We used HM (J. P. Hansen and I. R. McDonald) potential and introduced a truncated Coulomb interaction, which can avoid Coulomb catastrophe by choosing an appropriate cutting radius. The calculated results are compared with those from theoretical models (LS, GMS, BPS), whose applicability is also discussed. The effect of the interaction between ions and electrons on the temperature relaxation process is also investigated in the strong collision region. Finally, we discuss the effect of exchange interaction of electrons to the temperature relaxation.
Criterion for bulk behavior of a Yukawa disk
Sheridan, T. E.
2007-03-15
A Yukawa disk is a two-dimensional system of n particles interacting through a Yukawa potential (i.e., a screened Coulomb or Debye potential) with Debye length {lambda} and confined in an isotropic parabolic well where the single-particle oscillation frequency is {omega}{sub 0}. One example of a Yukawa disk is a two-dimensional complex (dusty) plasma. The emergence of bulk (macroscopic) behavior in a strongly coupled Yukawa disk is studied by considering the dependence of the normalized, squared breathing frequency {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2} (i.e., the bulk modulus) on n, {lambda}, the disk radius R{sub 0}, and the nearest-neighbor distance a. An analytical expression for {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2} is derived for the bulk limit, R{sub 0}>>{lambda}, with a/{lambda} finite. In the plasma regime a < or approx. {lambda}, so that each particle interacts with many other particles, {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2}{approx_equal}4 independent of a/{lambda}. In the nearest-neighbor regime a > or approx. {lambda}, short-range interactions dominate and {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2}{approx}a/{lambda}. Computational solutions of the model for n=100-3200 particles approach the theoretical bulk limit as n increases. Solutions with n=3200 and a/{lambda} between 0.25 and 0.5 are found to give the best approximation to an unbounded plasma.
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.
Macdonald, J. (Delaware, University, Newark (USA))
1991-05-01
The results of accurate calculations of collision integrals for the attractive static screened Coulomb potential are presented. To obtain high accuracy with minimal computational cost, the integrals are evaluated by a quadrature method based on the Whittaker cardinal function. The collision integrals for the attractive potential are needed for calculation of the electrical conductivity of a dense fully or partially ionized plasma, and the results presented here are appropriate for the conditions in the nondegenerate envelopes of white dwarf stars. 25 refs.
Analytic structure of the multichannel Jost matrix for potentials with Coulombic tails
Rakityansky, S. A. [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa)] [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Elander, N. [Division of Chemical Physics, Department of Physics, Stockholm University, Stockholm, SE-106 91 (Sweden)] [Division of Chemical Physics, Department of Physics, Stockholm University, Stockholm, SE-106 91 (Sweden)
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.
Asymptotic decay of pair correlations in a Yukawa fluid.
Hopkins, P; Archer, A J; Evans, R
2005-02-01
We analyze the r-->infinity asymptotic decay of the total correlation function h (r) for a fluid composed of particles interacting via a (point) Yukawa pair potential. Such a potential provides a simple model for dusty plasmas. The asymptotic decay is determined by the poles of the liquid structure factor in the complex plane. We use the hypernetted-chain closure to the Ornstein-Zernike equation to determine the line in the phase diagram, well removed from the freezing transition line, where crossover occurs in the ultimate decay of h (r) , from monotonic to damped oscillatory. We show that (i) crossover takes place via the same mechanism (coalescence of imaginary poles) as in the classical one-component plasma and in other models of Coulomb fluids and (ii) leading-order pole contributions provide an accurate description of h (r) at intermediate distances r as well as at long range. PMID:15783460
Dynamic simulation of sediment films of Yukawa-stabilized particles.
Brewer, Damien D; Kumar, Satish
2015-02-01
The fast lubrication dynamics method is applied to simulate the motion and deposition of charge-stabilized 100-nm-diam particles into sediment films from aqueous dispersions. Colloidal interactions are incorporated with a Yukawa potential and the effects of the screened-Coulomb potential strength and Péclet number (which controls the sedimentation driving force) on particle orientation are quantified with a sixfold bond order parameter. The effect of sediment growth rate on the order parameter is determined and related to a competition between the electrostatic interaction strength and sedimentation driving force. Increasing the electrostatic interaction strength and decreasing the Péclet number lead to lower sediment growth rates and consequently greater sixfold bond order. Our work demonstrates the feasibility of including lubrication interactions in dynamic simulations of sediment films and suggests that these interactions play a central role in the kinetics of film microstructure development and consequently in the degree of order within the film. PMID:25768502
Asymptotic decay of pair correlations in a Yukawa fluid
P. Hopkins; A. J. Archer; R. Evans
2005-12-16
We analyse the $r \\to \\infty$ asymptotic decay of the total correlation function, $h(r)$, for a fluid composed of particles interacting via a (point) Yukawa pair potential. Such a potential provides a simple model for dusty plasmas. The asymptotic decay is determined by the poles of the liquid structure factor in the complex plane. We use the hypernetted-chain closure to the Ornstein-Zernike equation to determine the line in the phase diagram, well-removed from the freezing transition line, where crossover occurs in the ultimate decay of $h(r)$, from monotonic to damped oscillatory. We show: i) crossover takes place via the same mechanism (coalescence of imaginary poles) as in the classical one-component plasma and in other models of Coulomb fluids and ii) leading-order pole contributions provide an accurate description of $h(r)$ at intermediate distances $r$ as well as at long range.
NASA Astrophysics Data System (ADS)
Takahashi, Hiroshi
2005-12-01
The Coulomb potential is screened by high density mobile deuterons more than the electrons in the PdDx deuteride, and the coherent motion of deuteron might play an important role for analysis of the low-energy nuclear reaction in condensed matter. Together with the group theoretical approach used in nuclear physics, the quantum field theory might provide a sound foundation for analysis of anomalous phenomena occurs through many coherent modes interaction among the electron, deuteron and nucleus and facilitate.
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.
Three-potential formalism for the three-body scattering problem with attractive Coulomb interactions
Papp, Z; Hlousek, Zvonimir T; Kónya, B; Yakovlev, S L
2001-01-01
A three-body scattering process in the presence of Coulomb interaction can be decomposed formally into a two-body single channel, a two-body multichannel and a genuine three-body scattering. The corresponding integral equations are coupled Lippmann-Schwinger and Faddeev-Merkuriev integral equations. We solve them by applying the Coulomb-Sturmian separable expansion method. We present elastic scattering and reaction cross sections of the $e^++H$ system both below and above the $H(n=2)$ threshold. We found excellent agreements with previous calculations in most cases.
Sameer M. Ikhdair; Ramazan Sever
2007-03-06
We present analytically the exact energy bound-states solutions of the Schrodinger equation in D-dimensions for an alternative (often used) pseudo-Coulomb potential-plus- ring-shaped potential of the form $V(r)=-% \\frac{a}{r}+\\frac{b}{r^{2}}+\\frac{\\beta \\cos ^{2}\\theta}{r^{2}\\sin ^{2}\\theta }+c$ by means of the conventional Nikiforov-Uvarov method. We give a clear recipe of how to obtain an explicit solution to the radial and angular parts of the wave functions in terms of orthogonal polynomials. The total energy of the system is different from the pseudo-Coulomb potential because of the contribution of the angular part. The general results obtained in this work can be reduced to the standard forms given in literature.
Exactness in the Path Integral of the Coulomb Potential in One Space Dimension
NASA Astrophysics Data System (ADS)
Sakoda, Sejii
We solve time-sliced path integrals of one-dimensional Coulomb system in an exact manner. In formulating path integrals, we make use of the Duru-Kleinert transformation with Fujikawa's gauge theoretical technique. Feynman kernels in the momentum representation both for bound states and scattering states will be obtained with clear pole structure that explains the exactness of the path integral. The path integrals presented here can be, therefore, evaluated exactly by making use of Cauchy's integral theorem.
NASA Astrophysics Data System (ADS)
Popescu, Radian; Müller, Erich; Wanner, Matthias; Gerthsen, Dagmar; Schowalter, Marco; Rosenauer, Andreas; Böttcher, Artur; Löffler, Daniel; Weis, Patrick
2007-12-01
Electron holography in a transmission electron microscope was applied to measure the phase shift ?? induced by Au clusters as a function of the cluster size. Large ?? observed for small Au clusters cannot be described by the well-known equation ??=CEV0t ( CE , interaction constant; V0 , 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 ?? can be explained by the compressive strain of surface atoms in the cluster.
Parabolic Behavior of Melting and Boiling Points versus Coulomb Potential in Ionic Substances
NASA Astrophysics Data System (ADS)
Nakamura, Tetsur?; Takagi, Yoshiki
1980-04-01
Melting points and boiling points of alkali fluorides, alkali chlorides, alkali bromides and alkali iodides, have been found to form parabolas as a function of Coulomb energy x{=}q2/(rc+ra). Melting points versus x for oxides of cations with rare gas-type outer electronic shells have been found to behave similarly. A primary explanation of such parabolic behaviors of melting points versus x is given and a quartic behaviors of enthalpy of fusion versus x for ionic substances which is caused by multipole interactions in ionic liquids is demonstrated.
Off-shell Jost solution for a Coulomb-like potential
Laha, U.
2006-07-15
The theory of ordinary differential equations together with judicious use of boundary conditions and certain properties of higher transcendental functions is exploited to derive a useful analytical expression for the Coulomb-Yamaguchi Jost solution through an r-space approach to the problem. Note that the off-shell Jost solution is expressed in its maximal reduced form involving confluent and Gaussian hypergeometric functions. As an application of the Jost solution the off-shell T matrix is also expressed in terms of Gaussian hypergeometric functions.
Time-dependent correlation buildup in spherical Yukawa balls
NASA Astrophysics Data System (ADS)
Kaehlert, Hanno; Bonitz, Michael
2009-11-01
In recent years it has become possible to create 3D dust crystals in experiments [1], where the particles arrange on concentric spherical shells. Compared to confined ions the interaction between the dust particles is screened, which has been shown to affect the shell occupation of the ground state [2], and the probability of metastable states [3,4]. Here we study dynamical processes in a trapped Yukawa plasma by means of Langevin dynamics simulations, which fully include the Coulomb correlations, the confinement and friction with the neutral gas. By cooling a weakly correlated initial state towards the strong coupling regime, the formation of concentric shells is observed. While in systems with Coulomb interaction the shells clearly emerge at the cluster boundary, they appear almost simultaneously for sufficiently large screening. Monte Carlo simulations are used to show that the sequence, in which radial order is established, is determined by the confinement potential.[4pt] [1] O. Arp, D. Block, A. Piel, and A. Melzer, PRL 93, 165004 (2004)[0pt] [2] H. Baumgartner et al., New J. Phys. 10, 093019 (2008)[0pt] [3] D. Block et al., Phys. Plasmas 15, 040701 (2008)[0pt] [4] H. K"ahlert et al., Phys. Rev. E 78, 036408 (2008)
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.
Phonons in a one-dimensional Yukawa chain: Dusty plasma experiment and model Bin Liu* and J. Goree
Goree, John
Phonons in a one-dimensional Yukawa chain: Dusty plasma experiment and model Bin Liu* and J. Goree interacting with a Yukawa potential, moving in a horizontal plane and confined by a harmonic potential
PHYSICAL REVIEW E 87, 013106 (2013) Longitudinal viscosity of two-dimensional Yukawa liquids
Goree, John
2013-01-01
PHYSICAL REVIEW E 87, 013106 (2013) Longitudinal viscosity of two-dimensional Yukawa liquids Yan. The interparticle potential used has the Debye-HÂ¨uckel or Yukawa form, which models a 2D dusty plasma differences for the entire range of temperatures that is considered. For a 2D Yukawa liquid, the bulk
Greensite, J.; Olejnik, S.
2003-09-26
We study the phase structure of SU(2) gauge theories at zero and high temperature, with and without scalar matter fields, in terms of the symmetric/broken realization of the remnant gauge symmetry which exists after fixing to Coulomb gauge. The symmetric realization is associated with a linearly rising color Coulomb potential (which we compute numerically), and is a necessary but not sufficient condition for confinement.
G-essence with Yukawa Interactions
I. Kulnazarov; K. Yerzhanov; O. Razina; Sh. Myrzakul; P. Tsyba; R. Myrzakulov
2011-07-25
We study the g-essence model with Yukawa interactions between a scalar field $\\phi$ and a Dirac field $\\psi$. For the homogeneous, isotropic and flat Friedmann-Robertson-Walker universe filled with the such g-essence, the exact solution of the model is found. Moreover, we reconstruct the corresponding scalar and fermionic potentials which describe the coupled dynamics of the scalar and fermionic fields. It is shown that some particular g-essence models with Yukawa interactions correspond to the usual and generalized Chaplygin gas unified models of dark energy and dark matter. Also we present some scalar-fermionic Dirac-Born-Infeld models corresponding g-essence models with Yukawa interactions which again describe the unified dark energy-dark matter system.
Mixing parameters of neutral beauty mesons from the Coulomb plus power potential (CPP?)
NASA Astrophysics Data System (ADS)
Patel, Bhavin; Vinodkumar, P. C.
2009-11-01
The investigation of mixing parameters in neutral B meson systems provides an important testing ground for standard model flavour dynamics. The spectroscopic parameters deduced from the potential model are used to calculate the pseudoscalar decay constant and mixing parameters of the B and Bs mesons.
Ashok K. Dham; Frederick R. W. McCourt; William J. Meath
2009-01-01
Exchange-Coulomb model potential energy surfaces have been developed for the Ne–CO interaction. The initial model is a three-dimensional potential energy surface based upon computed Heitler–London interaction energies and literature results for the long-range induction and dispersion energies, all as functions of interspecies distance, the orientation of CO relative to the interspecies axis, and the bond length of the CO molecule.
Ashok K. Dham; George C. McBane; Frederick R. W. McCourt; William J. Meath
2010-01-01
Four potential energy surfaces are of current interest for the Ne–CO interaction. Two are high-level fully ab initio surfaces obtained a decade ago using symmetry-adapted perturbation theory and supermolecule coupled-cluster methods. The other two are very recent exchange-Coulomb (XC) model potential energy surfaces constructed by using ab initio Heitler–London interaction energies and literature long range dispersion and induction energies, followed
Ashok K. Dham; Frederick R. W. McCourt; William J. Meath
2009-01-01
Exchange-Coulomb model potential energy surfaces have been developed for the Ne-CO interaction. The initial model is a three-dimensional potential energy surface based upon computed Heitler-London interaction energies and literature results for the long-range induction and dispersion energies, all as functions of interspecies distance, the orientation of CO relative to the interspecies axis, and the bond length of the CO molecule.
Ashok K. Dham; George C. McBane; Frederick R. W. McCourt; William J. Meath
2010-01-01
Four potential energy surfaces are of current interest for the Ne-CO interaction. Two are high-level fully ab initio surfaces obtained a decade ago using symmetry-adapted perturbation theory and supermolecule coupled-cluster methods. The other two are very recent exchange-Coulomb (XC) model potential energy surfaces constructed by using ab initio Heitler-London interaction energies and literature long range dispersion and induction energies, followed
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.
Coulomb Crystal Experiments in Dusty Plasmas
NASA Astrophysics Data System (ADS)
Goree, J.
2001-04-01
Over the past ten years, the most rapidly growing area of plasma physics has been "dusty plasmas." A dusty plasma is an ionized gas that also contains micron-size particles of solid matter, which gain a large electric charge Q -10,000 e. Because the inter-particle potential energy for the Coulomb interaction scales as the square of Q, the large charge results in an interparticle potential energy that can be larger than the particle thermal energy. This condition, which is typical of liquids and solids, is the opposite of what is usually true in a plasma consisting only of electrons and ions. In experiments, we shake polymer microspheres into a low-temperature gas discharge plasma, and image the icrospheres directly, using video microscopy. This allows us to image where all the particles are, and follow them as they move around. It is easy to perform an experiment where the particles arrange in a lattice, analogous to a crystal in an ordinary atomic solid. This lattice is sometimes termed a "Coulomb crystal" or "Wigner lattice." Like an ordinary crystal, it has both structure and dynamics. Early experiments in the field focused mainly on crystalline structure and the melting transition, whereby the lattice becomes disordered. The field is still immature, with new phenomena and research directions constantly developing. In this talk, I will report experiments with a monolayer crystalline lattice that is disturbed so that phonons, or sound waves, propagate through the lattice. There are two kinds of phonons, corresponding to compressional and shear motion, analogous to the P and S waves of seismology. Experiments have been performed to measure the dispersion relations (i.e., phonon spectra) of these two waves. To excite the wave, we stimulate the lattice using the radiation pressure of an argon laser. These experiments are compared to molecular dynamics simulations with a Yukawa interparticle potential.
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.
Coexistence of hexatic and isotropic phases in two-dimensional Yukawa systems
Wei-Kai Qi; Shao-Meng Qin; Xiao-Ying Zhao; Yong Chen
2008-09-03
We have performed Brownian dynamics simulations on melting of two-dimensional colloidal crystal in which particles interact with Yukawa potential. The pair correlation function and bond-orientational correlation function was calculated in the Yukawa system. An algebraic decay of the bond orientational correlation function was observed. By ruling out the coexistence region, only a unstable hexatic phase was found in the Yukawa systems. But our work shows that the melting of the Yukawa systems is a two-stage melting not consist with the KTHNY theory and the isotropic liquid and the hexatic phase coexistence region was found. Also we have studied point defects in two-dimensional Yukawa systems.
Yukawa Institute For Theoretical Physics
Shimizu, Akira
ÃÃ?Ã? Ã?Ã?Ã? Ã Ã? Ã?Ã?Ã?Ã? Yukawa Institute For Theoretical Physics Kyoto University Â¾Â¼Â¼Â½ Â¾Â¼Â¼Â¿ #12;#12;Foreword This is an `annual report' of the Yukawa Institute for Theoretical Physics to give a report on our, organisation, services and facilities of our institute, can be found in the WWW homepage, http://www.yukawa
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
Realistic Yukawa Couplings through Instantons in Intersecting Brane Worlds
Steven A. Abel; Mark D. Goodsell
2007-10-17
The Yukawa couplings of the simpler models of D-branes on toroidal orientifolds suffer from the so-called ``rank one'' problem -- there is only a single non-zero mass and no mixing. We consider the one-loop contribution of E2-instantons to Yukawa couplings on intersecting D6-branes, and show that they can solve the rank one problem. In addition they have the potential to provide a geometric explanation for the hierarchies observed in the Yukawa coupling. In order to do this we provide the necessary quantities for instanton calculus in this class of background.
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…
W. Y. So; T. Udagawa; K. S. Kim; S. W. Hong; B. T. Kim
2006-12-13
Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous $\\chi^{2}$ analyses are performed for elastic scattering and fusion cross section data for the $^{6}$Li+$^{208}$Pb system at near-Coulomb-barrier energies. A folding potential is used as the bare potential. It is found that the real part of the resultant DR part of the polarization potential is repulsive, which is consistent with the results from the Continuum Discretized Coupled Channel (CDCC) calculations and the normalization factors needed for the folding potentials. Further, it is found that both DR and fusion parts of the polarization potential satisfy separately the dispersion relation.
Color-Coulomb Force Calculated from Lattice Coulomb Hamiltonian
Cucchieri, A; Cucchieri, Attilio; Zwanziger, Daniel
1996-01-01
The static color-Coulomb potential is calculated as the solution of a non-linear integral equation. This equation has been derived recently as a self-consistency condition which arises in the Coulomb Hamiltonian formulation of lattice gauge theory when the restriction to the interior of the Gribov horizon is implemented. The potential obtained is in qualitative agreement with expectations, being Coulombic with logarithmic corrections at short range and confining at long range. The values obtained for the string tension and Carlo and phenomenological determinations.
Probability of metastable states in Yukawa clusters
NASA Astrophysics Data System (ADS)
Ludwig, Patrick; Kaehlert, Hanno; Baumgartner, Henning; Bonitz, Michael
2008-11-01
Finite strongly coupled systems of charged particles in external traps are of high interest in many fields. Here we analyze the occurrence probabilities of ground- and metastable states of spherical, three-dimensional Yukawa clusters by means of molecular dynamics and Monte Carlo simulations and an analytical method. We find that metastable states can occur with a higher probability than the ground state, thus confirming recent dusty plasma experiments with so-called Yukawa balls [1]. The analytical method [2], based on the harmonic approximation of the potential energy, allows for a very intuitive explanation of the probabilities when combined with the simulation results [3].[1] D. Block, S. Käding, A. Melzer, A. Piel, H. Baumgartner, and M. Bonitz, Physics of Plasmas 15, 040701 (2008)[2] F. Baletto and R. Ferrando, Reviews of Modern Physics 77, 371 (2005)[3] H. Kählert, P. Ludwig, H. Baumgartner, M. Bonitz, D. Block, S. Käding, A. Melzer, and A. Piel, submitted for publication (2008)
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.
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)
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).
Coulombic contribution and fat center vortex model
Rafibakhsh, Shahnoosh; Deldar, Sedigheh [Department of Physics, University of Tehran, P.O. Box 14395/547, Tehran 1439955961 (Iran, Islamic Republic of)
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
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.
Yukawa bosons in two-dimensional harmonic confinement
Rajagopal, K. K.
2007-08-01
The ground state property of Yukawa Bose fluid confined in a radial harmonic trap is studied. The calculation was carried out using the density functional theory formalism within the Kohn-Sham scheme. The excess-correlation energy for this inhomogeneous fluid is approximated via the local density approximation. A comparison is also made with the Gross-Piteavskii model. We found that the system of bosons interacting in terms of Yukawa potential in a harmonic trap is energetically favorable compared to the ones interacting via contact delta potential.
Spinless particles with unequal Scalar-Vector Yukawa interactions
Majid Hamzavi; Sameer M. Ikhdair
2012-07-03
We present analytical solutions of the spin-zero Klein-Gordon (KG) bosons in the field of unequal mixture of scalar and vector Yukawa potential within the framework of the approximation to the centrifugal potential term for any arbitrary -state. The explicit forms of the energy bound states including energy spectra and unnormalized wave functions are obtained using a simple shortcut of the Nikiforov-Uvarov (NU) method. Our numerical tests using energy calculations demonstrate the existence of inter dimensional degeneracy amongst energy states of the present quantum system consisting of the KG-Yukawa problem. The dependence of the energy on the dimension is numerically discussed for
P. Gerhold; K. Jansen
2007-06-26
We consider a chirally invariant lattice Higgs-Yukawa model based on the Neuberger overlap operator. As a first step towards the eventual determination of Higgs mass bounds we study the phase diagram of the model analytically in the large Nf-limit. We present an expression for the effective potential at tree-level in the regime of small Yukawa and quartic coupling constants and determine the order of the phase transitions. In the case of strong Yukawa couplings the model effectively becomes an O(4)-symmetric non-linear sigma-model for all values of the quartic coupling constant. This leads to the existence of a symmetric phase also in the regime of large values of the Yukawa coupling constant. On finite and small lattices, however, strong finite volume effects prevent the expectation value of the Higgs field from vanishing thus obscuring the existence of the symmetric phase at strong Yukawa couplings.
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 /) Yukawa's early U field: Scalar Isovect
Sameer M. Ikhdair; Ramazan Sever
2010-01-22
We study the effect of spatially dependent mass function over the solution of the Dirac equation with the Coulomb potential in the (3+1)-dimensions for any arbitrary spin-orbit $\\kappa $ state$.$ In the framework of the spin and pseudospin symmetry concept, the analytic bound state energy eigenvalues and the corresponding upper and lower two-component spinors of the two Dirac particles are obtained by means of the Nikiforov-Uvarov method, in closed form. This physical choice of the mass function leads to an exact analytical solution for the pseudospin part of the Dirac equation. The special cases $% \\kappa =\\pm 1$ ($l=\\widetilde{l}=0,$ i.e., s-wave)$,$ the constant mass and the non-relativistic limits are briefly investigated.
Voicu Dolocan
2015-07-27
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 a splitting of every energy level associated with a set of quantum numbers n,l and jinto two levels of slightly different energy, depending on the relative orientation of the proton magnetic dipole and the electron state. This is the hyperfine structure. Also, we have obtained the fine structure and Lamb shift.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.
Yukawa Couplings in Heterotic Compactification
Lara B. Anderson; James Gray; Dan Grayson; Yang-Hui He; Andre Lukas
2009-04-15
We present a practical, algebraic method for efficiently calculating the Yukawa couplings of a large class of heterotic compactifications on Calabi-Yau three-folds with non-standard embeddings. Our methodology covers all of, though is not restricted to, the recently classified positive monads over favourable complete intersection Calabi-Yau three-folds. Since the algorithm is based on manipulating polynomials it can be easily implemented on a computer. This makes the automated investigation of Yukawa couplings for large classes of smooth heterotic compactifications a viable possibility.
arXiv:cond-mat/0511209v18Nov2005 Test of the Stokes-Einstein relation in a two-dimensional Yukawa
Goree, John
arXiv:cond-mat/0511209v18Nov2005 Test of the Stokes-Einstein relation in a two-dimensional Yukawa-dynamics simulation was used with a Yukawa pair potential. Regimes are identified where motion is diffusive and D in strings [9]. Our 2D system is composed of molecules or particles that interact with a Yukawa pair
SO(10) Yukawa Unification with mu < 0
Ilia Gogoladze; Qaisar Shafi; Cem Salih Un
2011-07-06
We consider the low energy implications including particle spectroscopy of SO(10) inspired t-b-tau Yukawa coupling unification with mu Yukawa unified supersymmetric SO(10) models with universal gaugino masses and mu > 0. We find that t-b-tau Yukawa unification with mu Yukawa unification with mu > 0 and universal gaugino masses in which the gluino is the lightest colored sparticle and the sqaurks of the first two families have masses in the multi-TeV range.
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2009 #12;#12;Foreword We present here an annual report of the scientific activities of Yukawa Institute for Theo- retical Physics during the academic year 2009. From the year 2007 we started our new project of "Yukawa
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2006 #12;#12;Foreword We present here an annual report of the scientific activities of Yukawa Institute for Theo- retical in individual fields. From the year 2006 we started our new project of "Yukawa International Program of Quark
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2012 #12;#12;Foreword We present here an annual report of the scientific activities of Yukawa Institute for Theo- retical Physics during the academic year 2012. From the year 2007 we started our new project of "Yukawa
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2004 #12;#12;Foreword We here present the annual report of the Yukawa Institute for Theoretical Physics (YITP) to make in 1953, in com- memoration of Prof. Yukawa's winning of the first Nobel Prize in Japan, as the first
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2007 #12;#12;Foreword We present here an annual report of the scientific activities of Yukawa Institute for Theo- retical project of "Yukawa International Pro- gram of Quark-Hadron Sciences (YIPQS)" funded by Japan Minsitry
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2010 #12;#12;Foreword We present here an annual report of the scientific activities of Yukawa Institute for Theo- retical Physics during the academic year 2010. From the year 2007 we started our new project of "Yukawa
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2008 #12;#12;Foreword We present here an annual report of the scientific activities of Yukawa Institute for Theo- retical project of "Yukawa International Pro- gram of Quark-Hadron Sciences (YIPQS)" funded by Japan Minsitry
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2013 #12;#12;Foreword We present here an annual report of the scientific activities of Yukawa Institute for Theo- retical Physics during the academic year 2013. From the year 2007 we started our new project of "Yukawa
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2005 #12;#12;Foreword We here present the annual report of the Yukawa Institute for Theoretical Physics (YITP was founded in 1953, in commemoration of Prof. Yukawa's winning of the first Nobel Prize in Japan
On the corresponding states law of the Yukawa fluid
Pedro Orea; Yurko Duda
2008-01-24
We have analyzed the currently available simulation results, as well as performed some additional Monte Carlo simulation for the hard-core attractive Yukawa fluid in order to study its corresponding state behavior. We show that the values of reduced surface tension map onto the master curve, and a universal equation of state can be obtained in the wide range of the attractive Yukawa tail length after a certain re-scaling of the number density. Some comparisons with other nonconformal potentials are presented and discussed.
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.
Gravitational corrections to Yukawa systems
O. Zanusso; L. Zambelli; G. P. Vacca; R. Percacci
2010-04-26
We compute the gravitational corrections to the running of couplings in a scalar-fermion system, using the Wilsonian approach. Our discussion is relevant for symmetric as well as for broken scalar phases. We find that the Yukawa and quartic scalar couplings become irrelevant at the Gaussian fixed point.
Vacuum stability of asymptotically safe gauge-Yukawa theories
Litim, Daniel F; Sannino, Francesco
2015-01-01
We study the phase diagram and the stability of the ground state for certain four-dimensional gauge-Yukawa theories whose high-energy behaviour is controlled by an interacting fixed point. We also provide analytical and numerical results for running couplings, their crossover scales, the separatrix, and the Coleman-Weinberg effective potential. Classical and quantum stability of the vacuum is established.
Vacuum stability of asymptotically safe gauge-Yukawa theories
Daniel F. Litim; Matin Mojaza; Francesco Sannino
2015-01-13
We study the phase diagram and the stability of the ground state for certain four-dimensional gauge-Yukawa theories whose high-energy behaviour is controlled by an interacting fixed point. We also provide analytical and numerical results for running couplings, their crossover scales, the separatrix, and the Coleman-Weinberg effective potential. Classical and quantum stability of the vacuum is established.
Yukawa-unified natural supersymmetry
Howard Baer; Sabine Kraml; Suchita Kulkarni
2012-08-24
Previous work on t-b-\\tau Yukawa-unified supersymmetry, as expected from SUSY GUT theories based on the gauge group SO(10), tended to have exceedingly large electroweak fine-tuning (EWFT). Here, we examine supersymmetric models where we simultaneously require low EWFT ("natural SUSY") and a high degree of Yukawa coupling unification, along with a light Higgs scalar with m_h\\sim125 GeV. As Yukawa unification requires large tan\\beta\\sim50, while EWFT requires rather light third generation squarks and low \\mu\\sim100-250 GeV, B-physics constraints from BR(B\\to X_s\\gamma) and BR(B_s\\to \\mu+\\mu-) can be severe. We are able to find models with EWFT \\Delta\\lesssim 50-100 (better than 1-2% EWFT) and with Yukawa unification as low as R_yuk\\sim1.3 (30% unification) if B-physics constraints are imposed. This may be improved to R_yuk\\sim1.2 if additional small flavor violating terms conspire to improve accord with B-constraints. We present several Yukawa-unified natural SUSY (YUNS) benchmark points. LHC searches will be able to access gluinos in the lower 1-2 TeV portion of their predicted mass range although much of YUNS parameter space may lie beyond LHC14 reach. If heavy Higgs bosons can be accessed at a high rate, then the rare H, A\\to \\mu+\\mu- decay might allow a determination of tan\\beta\\sim50 as predicted by YUNS models. Finally, the predicted light higgsinos should be accessible to a linear e+e- collider with \\sqrt{s}\\sim0.5 TeV.
NASA Astrophysics Data System (ADS)
Drewsen, Michael
2015-03-01
The following text will give a brief introduction to the physics of the spatially ordered structures, so-called Coulomb crystals, that appear when confined ions are cooled to sufficiently low temperatures. It will as well briefly comment on the very diverse scientific applications of such crystals, which have emerged the past two decades. While this document lacks figures, it includes a substantial number of references in which more detailed information can be found. It is the hope that the text will stimulate the reader to dig deeper into one or more of the discussed subjects and inspire her/him to think about new potential applications.
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.
Off-shell Jost solutions for Coulomb and Coulomb-like interactions in all partial waves
Laha, U.; Bhoi, J. [Department of Physics, National Institute of Technology, Jamshedpur 831014 (India)] [Department of Physics, National Institute of Technology, Jamshedpur 831014 (India)
2013-01-15
By exploiting the theory of ordinary differential equations, with judicious use of boundary conditions, interacting Green's functions and their integral transforms together with certain properties of higher transcendental functions, useful analytical expressions for the off-shell Jost solutions for motion in Coulomb and Coulomb-nuclear potentials are derived in maximal reduced form through different approaches to the problem in the representation space. The exact analytical expressions for the off-shell Jost solutions for Coulomb and Coulomb-like potentials are believed to be useful for the description of the charged particle scattering/reaction processes.
Yukawa Couplings on Quintic Threefolds
Ron Donagi; Rene Reinbacher; Shing-Tung Yau
2011-11-02
We compute the particle spectrum and some of the Yukawa couplings for a family of heterotic compactifications on quintic threefolds X involving bundles that are deformations of TX+O_X. These are then related to the compactifications with torsion found recently by Li and Yau. We compute the spectrum and the Yukawa couplings for generic bundles on generic quintics, as well as for certain stable non-generic bundles on the special Dwork quintics. In all our computations we keep the dependence on the vector bundle moduli explicit. We also show that on any smooth quintic there exists a deformation of the bundle TX+O_X whose Kodaira-Spencer class obeys the Li-Yau non-degeneracy conditions and admits a non-vanishing triple pairing.
Minimal Yukawa-Gauge Mediation
Federica Bazzocchi; Maurizio Monaco
2011-11-04
We consider a scenario in which Supersymmetry breaking is communicated to the MSSM fields through the interplay of yukawa and gauge interactions. The MSSM spectrum resembles that of split SUSY scenarios, but on top of that it develops some peculiar features like heavy higgsinos and an inverted hierarchy of sfermion masses. The predictions obtained are consistent with the most recent LHC SUSY and Higgs boson searches.
NASA Astrophysics Data System (ADS)
McClarty, P. A.; O'Brien, A.; Pollmann, F.
2014-05-01
We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.
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.
Leading Log Solution for Inflationary Yukawa
Shun-Pei Miao; R. P. Woodard
2008-05-11
We generalize Starobinskii's stochastic technique to the theory of a massless, minimally coupled scalar interacting with a massless fermion in a locally de Sitter geometry. The scalar is an ``active'' field that can engender infrared logarithms. The fermion is a ``passive'' field that cannot cause infrared logarithms but which can carry them, and which can also induce new interactions between the active fields. The procedure for dealing with passive fields is to integrate them out, then stochastically simplify the resulting effective action following Starobinski\\u{\\i}. Because Yukawa theory is quadratic in the fermion this can be done explicitly using the classic solution of Candelas and Raine. We check the resulting stochastic formulation against an explicit two loop computation. We also derive a nonperturbative, leading log result for the stress tensor. Because the scalar effective potential induced by fermions is unbounded below, back-reaction from this model might dynamically cancel an arbitrarily large cosmological constant.
Invariants in the Yukawa system's thermodynamic phase diagram
Veldhorst, Arno A; Dyre, Jeppe C
2015-01-01
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-squ...
A mean spherical model for soft potentials: The hard core revealed as a perturbation
NASA Technical Reports Server (NTRS)
Rosenfeld, Y.; Ashcroft, N. W.
1978-01-01
The mean spherical approximation for fluids is extended to treat the case of dense systems interacting via soft-potentials. The extension takes the form of a generalized statement concerning the behavior of the direct correlation function c(r) and radial distribution g(r). From a detailed analysis that views the hard core portion of a potential as a perturbation on the whole, a specific model is proposed which possesses analytic solutions for both Coulomb and Yukawa potentials, in addition to certain other remarkable properties. A variational principle for the model leads to a relatively simple method for obtaining numerical solutions.
Mean-spherical model for soft potentials - The hard core revealed as a perturbation
NASA Technical Reports Server (NTRS)
Rosenfeld, Y.; Ashcroft, N. W.
1979-01-01
The mean-spherical approximation for fluids is extended to treat the case of dense systems interacting via soft potentials. The extension takes the form of a generalized statement concerning the behavior of the direct-correlation function c(r) and the radial-distribution function g(r). From a detailed analysis that views the hard-core portion of a potential as a perturbation on the whole, a specific model is proposed which possesses analytic solutions for both Coulomb and Yukawa potentials, in addition to certain other remarkable properties. A variational principle for the model leads to a relatively simple method for obtaining numerical solutions.
YITP Annual Report Yukawa Institute For
Shimizu, Akira
YITP Annual Report Yukawa Institute For Theoretical Physics Kyoto University 2011 #12;#12;Foreword Physics during the academic year 2011. From the year 2007 we started our new project of "Yukawa International program of Quark-Hadron Sciences (YIPQS)" funded by Japan Ministry of Education, Culture, Sports
Successful Yukawa structures in Warped Extra Dimensions
J. I. Silva-Marcos
2007-03-27
For a RS model, with SM fields in the bulk and the Higgs boson on the TeV-brane, we suggest two specific structures for the Yukawa couplings, one based on a permutation symmetry and the other on the Universal Strength of Yukawa couplings hypothesis (USY). In USY, all Yukawa couplings have equal strength and the difference in the Yukawa structure lies in some complex phase. In both scenarios, all Yukawa couplings are of the same order of magnitude. Thus, the main features of the fermion hierarchies are explained through the RS geometrical mechanism, and not because some Yukawa coupling is extremely small. We find that the RS model is particularly appropriate to incorporate the suggested Yukawa configurations. Indeed, the RS geometrical mechanism of fermion locations along the extra dimension, combined with the two Yukawa scenarios, reproduces all the present experimental data on fermion masses and mixing angles. It is quite remarkable that in the USY case, only two complex phases of definite value +-Pi/2 are sufficient to generate the known neutrino mass differences, while at same time, permitting large leptonic mixing in agreement with experiment.
Power law behavior of the zigzag transition in Yukawa clusters
Sheridan, T. E.; Magyar, Andrew L.
2010-11-15
We provide direct experimental evidence that the width of a Yukawa cluster exhibits power law behavior during the one-dimensional (1D) to two-dimensional (2D) zigzag transition. Configurations of small dusty (complex) plasma clusters confined in a biharmonic potential well are characterized as the well anisotropy is varied. When the anisotropy is large the particles are in a 1D straight-line configuration. As the anisotropy is decreased the cluster undergoes a zigzag transition to a 2D configuration. The measured dependence of cluster width on anisotropy follows a power law. A second transition from the zigzag to an elliptical configuration is also observed. The results are in very good agreement with a model of identical particles interacting through a Yukawa potential.
Richard C. Thompson
2014-11-18
Ion Coulomb crystals (ICC), formed by atomic ions at low temperatures in radiofrequency and Penning ion traps, are structures that have remarkable properties and many applications. Images of Coulomb crystals are striking and reveal the crystal structure, which arises from a balance between the trapping forces acting on the ions and their mutual Coulomb repulsion. Applications of these structures range from frequency standards and quantum simulation through to measurement of the cross sections of chemical reactions of ions.
Gaussian and finite-element Coulomb method for the fast evaluation of Coulomb integrals
NASA Astrophysics Data System (ADS)
Kurashige, Yuki; Nakajima, Takahito; Hirao, Kimihiko
2007-04-01
The authors propose a new linear-scaling method for the fast evaluation of Coulomb integrals with Gaussian basis functions called the Gaussian and finite-element Coulomb (GFC) method. In this method, the Coulomb potential is expanded in a basis of mixed Gaussian and finite-element auxiliary functions that express the core and smooth Coulomb potentials, respectively. Coulomb integrals can be evaluated by three-center one-electron overlap integrals among two Gaussian basis functions and one mixed auxiliary function. Thus, the computational cost and scaling for large molecules are drastically reduced. Several applications to molecular systems show that the GFC method is more efficient than the analytical integration approach that requires four-center two-electron repulsion integrals. The GFC method realizes a near linear scaling for both one-dimensional alanine ?-helix chains and three-dimensional diamond pieces.
W. Y. So; T. Udagawa; S. W. Hong; B. T. Kim
2008-01-15
Simultaneous $\\chi^{2}$ analyses are performed for elastic scattering and fusion cross section data for the $^{12}$C+$^{208}$Pb system at near-Coulomb-barrier energies by using the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and also that both DR and fusion parts of the polarization potential determined from the $\\chi^{2}$ analyses satisfy separately the dispersion relation. Furthermore, it is shown that the imaginary parts of both DR and fusion potentials at the strong absorption radius change very rapidly, which results in a typical threshold anomaly in the total imaginary potential as observed with tightly bound projectiles such as $\\alpha$-particle and $^{16}$O.
W. Y. So; T. Udagawa; K. S. Kim; S. W. Hong; B. T. Kim
2007-06-05
Simultaneous $\\chi^{2}$ analyses previously made for elastic scattering and fusion cross section data for the $^{6}$Li+$^{208}$Pb system is extended to the $^{7}$Li+$^{208}$Pb system at near-Coulomb-barrier energies based on the extended optical model approach, in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and that both the DR and fusion parts of the polarization potential determined from the $\\chi^{2}$ analyses satisfy separately the dispersion relation. Further, we find that the real part of the fusion portion of the polarization potential is attractive while that of the DR part is repulsive except at energies far below the Coulomb barrier energy. A comparison is made of the present results with those obtained from the Continuum Discretized Coupled Channel (CDCC) calculations and a previous study based on the conventional optical model with a double folding potential. We also compare the present results for the $^7$Li+$^{208}$Pb system with the analysis previously made for the $^{6}$Li+$^{208}$Pb system.
Coulomb Distortion in the Inelastic Regime
Patricia Solvignon, Dave Gaskell, John Arrington
2009-09-01
The Coulomb distortion effects have been for a long time neglected in deep inelastic scattering for the good reason that the incident energies were very high. But for energies in the range of earlier data from SLAC or at JLab, the Coulomb distortion could have the potential consequence of affecting the A-dependence of the EMC effect and of the longitudinal to transverse virtual photon absorption cross section ratio $R(x,Q^2)$.
NASA Astrophysics Data System (ADS)
Gonzalez-Melchor, Minerva; Mendez, Arlette; Alejandre, Jose
2015-03-01
When the movement of particles is performed predominantly in two dimensions, the systems can be considered at a good extent as two-dimensional. For instance the lipids in a bilayer, micrometric particles in a quasi-two-dimensional colloidal suspension, colloids in a monolayer deposited on the air-water interface, and DNA complexes trapped at the water surface can be described at a first approach as bidimensional fluids. These systems are important for many applications in surface and colloidal science. In simulations where the explicit interface between liquid and vapor is present, the line tension can be directly computed. In this work we present molecular dynamics results obtained for the liquid/vapor coexistence curve of 2D Yukawa fluids and for the line tension. A comparison with the three-dimensional case is also presented.
ERIC Educational Resources Information Center
Noll, Ellis; Koehlinger, Mervin; Kowalski, Ludwik; Swackhamer, Gregg
1998-01-01
Describes the use of a computer-linked camera to demonstrate Coulomb's law. Suggests a way of reducing the difficulties in presenting Coulomb's law by teaching the inverse square law of gravity and the inverse square law of electricity in the same unit. (AIM)
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.
Flavour constraints on multi-Higgs-doublet models: Yukawa alignment
NASA Astrophysics Data System (ADS)
Pich, A.
2010-12-01
In multi-Higgs-doublet models, the alignment in flavour space of all Yukawa matrices coupling to a given right-handed fermion guarantees the absence of tree-level flavour-changing neutral couplings, while introducing new sources of CP violation. With N Higgs doublets (and no right-handed neutrinos) the Yukawa Lagrangian is characterized by the fermion masses, the CKM quark mixing matrix and 3(N-1) complex couplings. Quantum corrections break the alignment, generating a minimal-flavour-violation structure with flavour-blind phases. The aligned multi-Higgs-doublet models lead to a rich and viable phenomenology with an interesting hierarchy of flavour-changing neutral current effects, suppressing them in light-quark systems while allowing potentially relevant signals in heavy-quark transitions.
Some Unfinished Thoughts on Strong Yukawa Couplings
Wei-Shu Hou
2012-01-29
Yukawa couplings of electroweak Goldstone bosons can be inferred from experiment, but the existence of an elementary Higgs boson is not yet an established fact. If a sequential chiral quark generation does exist, it would bring us now into the strong Yukawa coupling regime. Guided by a Bethe--Salpeter equation approach, we postulate that the leading collapse state, the (heavy) isotriplet and color-singlet $\\pi_1$ meson, becomes the Goldstone boson $G$ itself. Viewing it as a deeply bound state, a gap equation is constructed. This "`bootstrap" picture for electroweak symmetry breaking relies on strong Yukawa coupling, without providing any theory of the latter.
Comment on "Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit".
Carrillo-Bernal, M A; Núñez-Yépez, H N; Salas-Brito, A L; Solis, Didier A
2015-02-01
In the referred paper, the authors use a numerical method for solving ordinary differential equations and a softened Coulomb potential -1/?[x(2)+?(2)] to study the one-dimensional Coulomb problem by approaching the parameter ? to zero. We note that even though their numerical findings in the soft potential scenario are correct, their conclusions do not extend to the one-dimensional Coulomb problem (?=0). Their claims regarding the possible existence of an even ground state with energy -? with a Dirac-? eigenfunction and of well-defined parity eigenfunctions in the one-dimensional hydrogen atom are questioned. PMID:25768644
Resolutions of the Coulomb Operator
NASA Astrophysics Data System (ADS)
Gill, Peter
2007-03-01
The ``Resolution of the Identity Operator'' I ?| ?n>=
Minimal SUSY SO(10) and Yukawa unification
Okada, Nobuchika
2013-05-23
The minimal supersymmetric (SUSY) SO(10) model, where only two Higgs multiplets {l_brace}10 Circled-Plus 126-bar{r_brace} are utilized for Yukawa couplings with matter fields, can nicely fit the neutrino oscillation parameters as well as charged fermion masses and mixing angles. In the fitting of the fermion mass matrix data, the largest element in the Yukawa coupling with the 126-bar -plet Higgs (Y{sup 126}) is found to be of order one, so that the right see-saw scale should be provided by Higgs vacuum expectation values (VEVs) of {beta}(10{sup 14}GeV). This fact causes a serious problem, namely, the gauge coupling unification is spoiled because of the presence of many exotic Higgs multiples emerging at the see-saw scale. In order to solve this problem, we consider a unification between bottom-quark and tau Yukawa couplings (b - {tau} Yukawa coupling unification) at the grand unified theory (GUT) scale, due to threshold corrections of superpartners to the Yukawa couplings at the 1 TeV scale. When the b - {tau} Yukawa coupling unification is very accurate, the largest element in Y{sub 126} can become {beta}(0.01), so that the right see-saw scale is realized by the GUT scale VEV and the usual gauge coupling unification is maintained. Since the b - {tau} Yukawa unification alters the Yukawa coupling data at the GUT scale, we re-analyze the fitting of the fermion mass matrix data by taking all the relevant free parameters into account. Unfortunately, we find that no parameter region shows up to give a nice fit for the current neutrino oscillation data and therefore, the usual picture of the gauge coupling unification cannot accommodate the fermion mass matrix data fitting in our procedure.
Uniform derivation of Coulomb collisional transport thanks to Debye shielding
NASA Astrophysics Data System (ADS)
Escande, D. F.; Elskens, Yves; Doveil, F.
2015-01-01
The effective potential acting on particles in plasmas being essentially the Debye-shielded Coulomb potential, the particles collisional transport in thermal equilibrium is calculated for all impact parameters b, with a convergent expression reducing to Rutherford scattering for small b. No cutoff at the Debye length scale is needed, and the Coulomb logarithm is only slightly modified.
Shear Viscosity of Two-Dimensional Yukawa Systems in the Liquid State Bin Liu and J. Goree
Goree, John
]. At an atomic scale, gas atoms adsorb on the surface of substrates such as graphite [7]. Here we are concerned vertical motion, so that the system was 2D. The microspheres interacted with a Yukawa pair potential [17
An Alternative Yukawa Unified SUSY Scenario
James S. Gainer; Ran Huo; Carlos E. M. Wagner
2011-11-15
Supersymmetric SO(10) Grand Unified Theories with Yukawa unification represent an appealing possibility for physics beyond the Standard Model. However Yukawa unification is made difficult by large threshold corrections to the bottom mass. Generally one is led to consider models where the sfermion masses are large in order to suppress these corrections. Here we present another possibility, in which the top and bottom GUT scale Yukawa couplings are equal to a component of the charged lepton Yukawa matrix at the GUT scale in a basis where this matrix is not diagonal. Physically, this weak eigenstate Yukawa unification scenario corresponds to the case where the charged leptons that are in the 16 of SO(10) containing the top and bottom quarks mix with their counterparts in another SO(10) multiplet. Diagonalizing the resulting Yukawa matrix introduces mixings in the neutrino sector. Specifically we find that for a large region of parameter space with relatively light sparticles, and which has not been ruled out by current LHC or other data, the mixing induced in the neutrino sector is such that $sin^2 2\\Theta_{23} \\approx 1$, in agreement with data. The phenomenological implications are analyzed in some detail.
W. Y. So; T. Udagawa; K. S. Kim; S. W. Hong; B. T. Kim
2010-03-14
Based on the extended optical model with the double folding potential, in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous $\\chi^{2}$ analyses are performed of elastic scattering and fusion cross section data for the $^{9}$Be+$^{28}$Si, $^{144}$Sm, and $^{208}$Pb systems at near-Coulomb-barrier energies. We find that the real part of the resultant DR part of the polarization potential is systematically repulsive for all the targets considered, which is consistent with the results deduced from the Continuum Discretized Coupled Channel (CDCC) calculations taking into account the polarization effects due to breakup. Further, it is found that both DR and fusion parts of the extracted polarization potentials satisfy the dispersion relation.
Efficient evaluation of the Coulomb force in the Gaussian and finite-element Coulomb method.
Kurashige, Yuki; Nakajima, Takahito; Sato, Takeshi; Hirao, Kimihiko
2010-06-28
We propose an efficient method for evaluating the Coulomb force in the Gaussian and finite-element Coulomb (GFC) method, which is a linear-scaling approach for evaluating the Coulomb matrix and energy in large molecular systems. The efficient evaluation of the analytical gradient in the GFC is not straightforward as well as the evaluation of the energy because the SCF procedure with the Coulomb matrix does not give a variational solution for the Coulomb energy. Thus, an efficient approximate method is alternatively proposed, in which the Coulomb potential is expanded in the Gaussian and finite-element auxiliary functions as done in the GFC. To minimize the error in the gradient not just in the energy, the derived functions of the original auxiliary functions of the GFC are used additionally for the evaluation of the Coulomb gradient. In fact, the use of the derived functions significantly improves the accuracy of this approach. Although these additional auxiliary functions enlarge the size of the discretized Poisson equation and thereby increase the computational cost, it maintains the near linear scaling as the GFC and does not affects the overall efficiency of the GFC approach. PMID:20590181
Efficient evaluation of the Coulomb force in the Gaussian and finite-element Coulomb method
NASA Astrophysics Data System (ADS)
Kurashige, Yuki; Nakajima, Takahito; Sato, Takeshi; Hirao, Kimihiko
2010-06-01
We propose an efficient method for evaluating the Coulomb force in the Gaussian and finite-element Coulomb (GFC) method, which is a linear-scaling approach for evaluating the Coulomb matrix and energy in large molecular systems. The efficient evaluation of the analytical gradient in the GFC is not straightforward as well as the evaluation of the energy because the SCF procedure with the Coulomb matrix does not give a variational solution for the Coulomb energy. Thus, an efficient approximate method is alternatively proposed, in which the Coulomb potential is expanded in the Gaussian and finite-element auxiliary functions as done in the GFC. To minimize the error in the gradient not just in the energy, the derived functions of the original auxiliary functions of the GFC are used additionally for the evaluation of the Coulomb gradient. In fact, the use of the derived functions significantly improves the accuracy of this approach. Although these additional auxiliary functions enlarge the size of the discretized Poisson equation and thereby increase the computational cost, it maintains the near linear scaling as the GFC and does not affects the overall efficiency of the GFC approach.
Proton-proton scattering without Coulomb force renormalization
Skibinski, R; Witala, H; Glöckle, W
2009-01-01
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.
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.
Finite Coulomb Crystal Formation
NASA Astrophysics Data System (ADS)
Vasut, J.; Hyde, T.; Barge, L.
Dust particles immersed within a plasma environment, such as those in planetary rings or cometary environments, will acquire an electric charge. If the ratio of inter- particle potential energy to average kinetic energy is high enough the particles will form either a "liquid" structure with short-range ordering or a crystalline structure with long-range ordering. Since their discovery in laboratory environments in 1994 such crystals have been the subject of a variety of experimental, theoretical and numerical investigations. Most numerical and theoretical investigations have examined infinite systems assuming periodic boundary conditions. Since experimentally observed crystals are typically comprised of a few hundred particles this often leads to discrepancies between predicted theoretical results and experimental data. In addition, recent studies have concentrated on the importance of random charge variations between individual dust particles, but very little on the importance of size variations between the grains. Such size variations naturally lead to intergrain charge variations which can easily become much more important than those due to random charge fluctuations (which are typically less than one percent). Although such size variations can be largely eliminated experimentally by introducing mono-dispersive particles, many laboratory systems and all astrophysical environments contain significant size distributions. This study utilizes a modified Barnes -H u t code to conduct numerical modeling of Coulomb crystallization. It will be shown that finite systems can behave much differently than systems of infinite extent and that the particle size distribution plays an important role in determining the overall ordering of the system, particularly for the most-highly ordered states.
Rapid heating and cooling in two-dimensional Yukawa systems
Yan Feng; Bin Liu; J. Goree
2011-04-19
Simulations are reported to investigate solid superheating and liquid supercooling of two-dimensional (2D) systems with a Yukawa interparticle potential. Motivated by experiments where a dusty plasma is heated and then cooled suddenly, we track particle motion using a simulation with Langevin dynamics. Hysteresis is observed when the temperature is varied rapidly in a heating and cooling cycle. As in the experiment, transient solid superheating, but not liquid supercooling, is observed. Solid superheating, which is characterized by solid structure above the melting point, is found to be promoted by a higher rate of temperature increase.
Determining the SUSY-QCD Yukawa Coupling
Ayres Freitas; Peter Z Skands
2006-06-09
Among the firm predictions of softly broken supersymmetry is the identity of gauge couplings and the corresponding Yukawa couplings between gauginos, sfermions and fermions. In the event that a SUSY-like spectrum of new particles is discovered at future colliders, a key follow-up will be to test these relations experimentally. In detailed studies it has been found that the SUSY-Yukawa couplings of the electroweak sector can be studied with great precision at the ILC, but a similar analysis for the Yukawa coupling of the SUSY-QCD sector is far more challenging. Here a first phenomenological study for determining this coupling is presented, using a method which combines information from LHC and ILC.
Yukawa Textures, New Physics and Nondecoupling
Gustavo C. Branco; M. N. Rebelo; J. I. Silva-Marcos
2006-12-20
We point out that New Physics can play an important r\\^ ole in rescuing some of the Yukawa texture zero ans\\" atze which would otherwise be eliminated by the recent, more precise measurements of $V_{CKM}$. As an example, a detailed analysis of a four texture zero ansatz is presented, showing how the presence of an isosinglet vector-like quark which mixes with standard quarks, can render viable this Yukawa texture. The crucial point is the nondecoupling of the effects of the isosinglet quark, even for arbitrary large values of its mass.
Deviation of Yukawa coupling in gauge-Higgs unification
NASA Astrophysics Data System (ADS)
Adachi, Yuki; Maru, Nobuhito
2015-08-01
We study the deviation of the Yukawa coupling in the gauge-Higgs unification scenario from the Standard Model one. Taking into account the brane mass terms necessary for generating the flavor mixing and removing the exotic massless fermions, we derive an analytic formula determining the KK mass spectrum and Yukawa coupling. Applying the obtained results to the tau and bottom Yukawa couplings, we numerically calculate the ratio of the Yukawa couplings in the gauge-Higgs unification and in the Standard Model.
Deviation of Yukawa Coupling in Gauge-Higgs Unification
Yuki Adachi; Nobuhito Maru
2015-01-26
We study the deviation of yukawa coupling in the gauge-Higgs unification scenario from the Standard Model one. Taking into account the brane mass terms necessary for generating the flavor mixing and removing the exotic massless fermions, we derive an analytic formula determining the KK mass spectrum and yukawa coupling. Applying the obtained results to the tau and bottom yukawa couplings, we numerically calculate the ratio of the yukawa couplings in the gauge-Higgs unification and in the Standard Model.
Charge Neutral Yukawa Lattice Gas on a FCC Lattice
NASA Astrophysics Data System (ADS)
Huang, He; Mahanti, S. D.
2011-03-01
Structural phase transitions associated with the ordering of Ag and Sb ions in the quaternary systems, (AgSbTe2)x (PbTe)2 (1 - x) (of current thermoelectric interest) has been investigated using an anti-ferromagnetic 3-state Ising model on a FCC lattice with screened Coulomb interaction (Yukawa lattice gas (YLG) model). We have carried out Monte Carlo simulations (MCs) to study phase transitions (PT) in YLG. The nature and the strength of PT depend on the screening parameter ? . The transition is 1st order and the transition temperature Tc is a weak function of the concentration x (excepting when x ~ 0 or 1), in agreement with earlier work for ? = 0 . We find Tc (x , ?) = f (x) g (?) , where g (?) --> const when ? --> 0 and g (?) --> 0 when ? --> ? . For x = 0.5 , there are two special structures, layered and tubular which have the same ground state energy, independent of ? . This is understood by looking at the connectivity and ordering of ions. Above but near Tc , the generation rates of different micro structures have been analyzed using a simple surface energy density picture. MCs results agree with this analysis and show that the energy barriers decide the generation rates of different micro structures.
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.
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.
CP violation in hierarchical Yukawa models
Peccei, R. D.
2011-04-01
Because 4-dimensional CP is a good symmetry of many higher-dimensional theories, this suggests the possible existence of an universal CP-violating phase originating from the process of compactification. Such a phase, if it existed, would not be easy to uncover since the phases in Yukawa matrices are not simply related to the observed Cabibbo-Kobayashi-Maskawa phase {delta}. Hierarchical Yukawa models, of the type arising in F-theory GUT models provide an interesting exception. Recently, Heckman and Vafa studied a particular F-theory GUT model with hierarchical Yukawa matrices with complex phases of O(1) and showed, by examining the Jarlskog invariant, that this model leads to sin{delta}{approx}O(1). A more detailed examination of the model, although confirming their results, is seen to be also compatible with having a phase {delta}{sub o}={pi}/3 imprinted on the Hermitian Yukawa matrices, leading to sin{delta}{approx_equal}sin{delta}{sub o}.
Melting criteria for mesoscopic Yukawa crystals
Bonitz, Michael
to calculate the melting transition points as accurate as possible. The Lindemann definition of the meltingMelting criteria for mesoscopic Yukawa crystals Henning Baumgartner, Volodymyr Golubnichiy, Alexei] A. Melzer, A. Homann and A. Piel. Experimental investigation of the melting transition of the plasma
Neumann-type expansion of Coulomb functions
Marksteiner, P.; Badralexe, E.; Freeman, A.J. (Northwestern Univ., Evanston, IL (United States))
1994-03-01
An expansion is derived for the regular (power series) part of the Coulomb function, G[sub o]([eta], [rho]), in terms of Whittaker functions, which are closely related to the regular Coulomb functions F[sub l]([eta], [rho]). The expansion coefficients are given as a sum of three terms; each of the terms obeys a simple three-term recurrence relation. In conjunction with the downward recurrence method for the regular functions (which is also discussed), this expansion is very useful for computing the irregular Coulomb functions G[sub l]([eta], [rho]), in particular for an attractive potential ([eta] < O) and for small or moderately large values of [rho]. 10 refs., 1 tab.
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 ...
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
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
Multi-meson Yukawa interactions at criticality
Vacca, Gian Paolo
2015-01-01
The critical behavior of a relativistic $\\mathbb{Z}_2$-symmetric Yukawa model at zero temperature and density is discussed for a continuous number of fermion degrees of freedom and of spacetime dimensions, with emphasis on the role played by multi-meson exchange in the Yukawa sector. We argue that this should be generically taken into account in studies based on the functional renormalization group, either in four-dimensional high-energy models or in lower-dimensional condensed-matter systems. By means of the latter method, we describe the generation of multi-critical models in less then three dimensions, both at infinite and finite number of flavors. We also provide different estimates of the critical exponents of the chiral Ising universality class in three dimensions for various field contents, from a couple of massless Dirac fermions down to the supersymmetric theory with a single Majorana spinor.
Yukawa Couplings in Heterotic Standard Models
Volker Braun; Yang-Hui He; Burt A. Ovrut
2006-01-27
In this paper, we present a formalism for computing the Yukawa couplings in heterotic standard models. This is accomplished by calculating the relevant triple products of cohomology groups, leading to terms proportional to Q*H*u, Q*Hbar*d, L*H*nu and L*Hbar*e in the low energy superpotential. These interactions are subject to two very restrictive selection rules arising from the geometry of the Calabi-Yau manifold. We apply our formalism to the "minimal" heterotic standard model whose observable sector matter spectrum is exactly that of the MSSM. The non-vanishing Yukawa interactions are explicitly computed in this context. These interactions exhibit a texture rendering one out of the three quark/lepton families naturally light.
Coulomb-Sturmian matrix elements of the Coulomb Green's operator
Demir, F.; Hlousek, Z. T.; Papp, Z.
2006-07-15
The two-body Coulomb Hamiltonian, when calculated in Coulomb-Sturmian basis, has an infinite symmetric tridiagonal--i.e., Jacobi-matrix form. This Jacobi-matrix structure involves a continued-fraction representation for the inverse of the Green's matrix. The continued fraction can be transformed to a ratio of two {sub 2}F{sub 1} hypergeometric functions. From this result we find an exact analytic formula for the matrix elements of the Green's operator of the Coulomb Hamiltonian.
Coulomb Bound States of Strongly Interacting Photons.
Maghrebi, M F; Gullans, M J; Bienias, P; Choi, S; Martin, I; Firstenberg, O; Lukin, M D; Büchler, H P; Gorshkov, A V
2015-09-18
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. PMID:26430994
The box diagram in Yukawa theory
Bernard L. G. Bakker; Jorn K. Boomsma; Chueng-Ryong Ji
2006-10-30
We present a light-front calculation of the box diagram in Yukawa theory. The covariant box diagram is finite for the case of spin-1/2 constituents exchanging spin-0 particles. In light-front dynamics, however, individual time-ordered diagrams are divergent. We analyze the corresponding light-front singularities and show the equivalence between the light-front and covariant results by taming the singularities.
Nonlinear Magnetoplasmons in Strongly Coupled Yukawa Plasmas
Bonitz, M.; Ott, T.; Kaehlert, H.; Donko, Z.; Hartmann, P.
2010-07-30
The existence of plasma oscillations at multiples of the magnetoplasmon frequency in a strongly coupled two-dimensional magnetized Yukawa plasma is reported, based on extensive molecular dynamics simulations. These modes are the analogues of Bernstein modes which are renormalized by strong interparticle correlations. Their properties are theoretically explained by a dielectric function incorporating the combined effect of a magnetic field, strong correlations and finite temperature.
Nonperturbative Yukawa Couplings from String Instantons
Blumenhagen, Ralph [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany); Cvetic, Mirjam; Richter, Robert; Weigand, Timo [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6996 (United States); Luest, Dieter [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany); Arnold-Sommerfeld-Center, LMU Muenchen, Theresienstrasse 37, 80333 Munich (Germany)
2008-02-15
Nonperturbative D-brane instantons can generate perturbatively absent though phenomenologically relevant couplings for type II orientifold compactifications with D-branes. We discuss the generation of the perturbatively vanishing SU(5) GUT Yukawa coupling of type <10 10 5{sub H}>. Moreover, for a simple globally consistent intersecting D6-brane model, we discuss the generation of mass terms for matter fields. This can serve as a mechanism for decoupling exotic matter.
Yukawa Textures From Heterotic Stability Walls
Lara B. Anderson; James Gray; Burt Ovrut
2010-01-13
A holomorphic vector bundle on a Calabi-Yau threefold, X, with h^{1,1}(X)>1 can have regions of its Kahler cone where it is slope-stable, that is, where the four-dimensional theory is N=1 supersymmetric, bounded by "walls of stability". On these walls the bundle becomes poly-stable, decomposing into a direct sum, and the low energy gauge group is enhanced by at least one anomalous U(1) gauge factor. In this paper, we show that these additional symmetries can strongly constrain the superpotential in the stable region, leading to non-trivial textures of Yukawa interactions and restrictions on allowed masses for vector-like pairs of matter multiplets. The Yukawa textures exhibit a hierarchy; large couplings arise on the stability wall and some suppressed interactions "grow back" off the wall, where the extended U(1) symmetries are spontaneously broken. A number of explicit examples are presented involving both one and two stability walls, with different decompositions of the bundle structure group. A three family standard-like model with no vector-like pairs is given as an example of a class of SU(4) bundles that has a naturally heavy third quark/lepton family. Finally, we present the complete set of Yukawa textures that can arise for any holomorphic bundle with one stability wall where the structure group breaks into two factors.
Gebremedhin, Daniel H; Weatherford, Charles A
2015-02-01
This is a response to the comment we received on our recent paper "Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit." In that paper, we introduced a computational algorithm that is appropriate for solving stiff initial value problems, and which we applied to the one-dimensional time-independent Schrödinger equation with a soft Coulomb potential. We solved for the eigenpairs using a shooting method and hence turned it into an initial value problem. In particular, we examined the behavior of the eigenpairs as the softening parameter approached zero (hard Coulomb limit). The commenters question the existence of the ground state of the hard Coulomb potential, which we inferred by extrapolation of the softening parameter to zero. A key distinction between the commenters' approach and ours is that they consider only the half-line while we considered the entire x axis. Based on mathematical considerations, the commenters consider only a vanishing solution function at the origin, and they question our conclusion that the ground state of the hard Coulomb potential exists. The ground state we inferred resembles a ?(x), and hence it cannot even be addressed based on their argument. For the excited states, there is agreement with the fact that the particle is always excluded from the origin. Our discussion with regard to the symmetry of the excited states is an extrapolation of the soft Coulomb case and is further explained herein. PMID:25768645
Polonyi, J. [Theoretical Physics Laboratory, Louis Pasteur University, Strasbourg (France)
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.
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.
Yukawa sector in minimal D-brane models
NASA Astrophysics Data System (ADS)
Ennadifi, Salah Eddine
2015-07-01
We investigate the Yukawa couplings sector in the minimal gauge theory U(3) × U(2) × U(1) with the Standard Model chiral and Higgs spectrum based on three stacks of intersecting D-branes. In this model, stringy corrections are required to induce the missing Yukawa couplings and generate hierarchical pattern. Under the known data, we assign the realistic Yukawa texture and then bound their strengths.
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 $D\\geq 4$.
NASA Astrophysics Data System (ADS)
Caruso, F.; Martins, J.; Perlingeiro, L. D.; Oguri, V.
2015-08-01
The relativistic hydrogen atom in a 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 ? 4.
NASA Astrophysics Data System (ADS)
Akpan, N. Ikot; Zarrinkamar, S.; Eno, J. Ibanga; Maghsoodi, E.; Hassanabadi, H.
2014-01-01
We investigate the approximate solution of the Dirac equation for a combination of Möbius square and Mie type potentials under the pseudospin symmetry limit by using supersymmetry quantum mechanics. We obtain the bound-state energy equation and the corresponding spinor wave functions in an approximate analytical manner. We comment on the system via various useful figures and tables.
Local mirror symmetry of curves: Yukawa couplings and genus 1
Brian Forbes; Masao Jinzenji
2006-09-14
We continue our study of equivariant local mirror symmetry of curves, i.e. mirror symmetry for X_k=O(k)+O(-2-k) over P^1 with torus action (lambda_1,lambda_2) on the bundle. For the antidiagonal action lambda_1=-lambda_2, we find closed formulas for the mirror map and a rational B model Yukawa coupling for all k. Moreover, we give a simple closed form for the B model genus 1 Gromov-Witten potential. For the diagonal action lambda_1=lambda_2, we argue that the mirror symmetry computation is equivalent to that of the projective bundle P(O+O(k)+O(-2-k)) over P^1. Finally, we outline the computation of equivariant Gromov-Witten invariants for A_n singularities and toric tree examples via mirror symmetry.
Nonlinear compressional waves in a two-dimensional Yukawa lattice.
Avinash, K; Zhu, P; Nosenko, V; Goree, J
2003-10-01
A modified Korteweg-de Vries (KdV) equation is obtained for studying the propagation of nonlinear compressional waves and pulses in a chain of particles including the effect of damping. Suitably altering the linear phase velocity makes this equation useful also for the problem of phonon propagation in a two-dimensional (2D) lattice. Assuming a Yukawa potential, we use this method to model compressional wave propagation in a 2D plasma crystal, as in a recent experiment. By integrating the modified KdV equation the pulse is allowed to evolve, and good agreement with the experiment is found. It is shown that the speed of a compressional pulse increases with its amplitude, while the speed of a rarefactive pulse decreases. It is further discussed how the drag due to the background gas has a crucial role in weakening nonlinear effects and preventing the emergence of a soliton. PMID:14683049
Wave Functions and Yukawa Couplings in Local String Compactifications
Joseph P. Conlon; Anshuman Maharana; Fernando Quevedo
2008-07-06
We consider local models of magnetised D7 branes in IIB string compactifications, focussing on cases where an explicit metric can be written for the local 4-cycle. The presence of an explicit metric allows analytic expressions for the gauge bundle and for the chiral matter wavefunctions through solving the Dirac and Laplace equations. The triple overlap of the normalised matter wavefunctions generates the physical Yukawa couplings. Our main examples are the cases of D7 branes on P1xP1 and P2. We consider both supersymmetric and non-supersymmetric gauge backgrounds and both Abelian and non-Abelian gauge bundles. We briefly outline potential phenomenological applications of our results.
Coulomb Breakup of Deformed Halo Nuclei
NASA Astrophysics Data System (ADS)
Shubhchintak; Chatterjee, Rajdeep
We present a fully quantum mechanical theory to study the effects of deformation on various reaction observables in the Coulomb breakup of neutron rich exotic medium mass nuclei on heavy targets within the framework of post-form finite range distorted wave Born approximation by using a deformed Woods-Saxon potential. We study the cases of 31Ne and 37Mg, possible halo candidates in the medium mass region, of the nuclear chart.
The Nuclear Yukawa Model on a Lattice
F. de Soto; J. C. Angles d'Auriac; J. Carbonell
2011-04-11
We present the results of the quantum field theory approach to nuclear Yukawa model obtained by standard lattice techniques. We have considered the simplest case of two identical fermions interacting via a scalar meson exchange. Calculations have been performed using Wilson fermions in the quenched approximation. We found the existence of a critical coupling constant above which the model cannot be numerically solved. The range of the accessible coupling constants is below the threshold value for producing two-body bound states. Two-body scattering lengths have been obtained and compared to the non relativistic results.
Crystalline multilayers of the confined Yukawa system
Erdal Celal O?uz; René Messina; Hartmut Löwen
2009-03-18
The phase diagram of Yukawa particles confined between two parallel hard walls is calculated at zero-temperature beyond the bilayer regime by lattice-sum-minimization. Tuning the screening, a rich phase behavior is found in the regime bounded by stable two-triangular layers and 3-square layers. In this regime, alternating prism phases with square and triangular basis, structures derived from a hcp bulk lattice, and a structure with two outer layers and two inner staggered rectangular layers, reminiscent of a Belgian waffle iron, are stable. These structures are verifiable in experiments on charged colloidal suspensions and dusty plasma sheets.
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.
Measuring the Top Yukawa Coupling at 100 TeV
Michelangelo L. Mangano; Tilman Plehn; Peter Reimitz; Torben Schell; Hua-Sheng Shao
2015-09-01
We propose a measurement of the top Yukawa coupling at a 100 TeV hadron collider, based on boosted Higgs and top decays. We find that the top Yukawa coupling can be measured to 1%, with excellent handles for reducing systematic and theoretical uncertainties, both from side bands and from $t\\bar{t}H/t\\bar{t}Z$ ratios.
Zhang, Yubo; Zhang, Jiawei; Wang, Youwei; Gao, Weiwei; Abtew, Tesfaye A.; Zhang, Peihong E-mail: wqzhang@mail.sic.ac.cn; Beijing Computational Science Research Center, Beijing 100084 ; Zhang, Wenqing E-mail: wqzhang@mail.sic.ac.cn; School of Chemistry and Chemical Engineering and Sate Key Laboratory of Coordination Chemistry, Nanjing University, Jiangsu 210093
2013-11-14
Diamond-like Cu-based multinary semiconductors are a rich family of materials that hold promise in a wide range of applications. Unfortunately, accurate theoretical understanding of the electronic properties of these materials is hindered by the involvement of Cu d electrons. Density functional theory (DFT) based calculations using the local density approximation or generalized gradient approximation often give qualitative wrong electronic properties of these materials, especially for narrow-gap systems. The modified Becke-Johnson (mBJ) method has been shown to be a promising alternative to more elaborate theory such as the GW approximation for fast materials screening and predictions. However, straightforward applications of the mBJ method to these materials still encounter significant difficulties because of the insufficient treatment of the localized d electrons. We show that combining the promise of mBJ potential and the spirit of the well-established DFT + U method leads to a much improved description of the electronic structures, including the most challenging narrow-gap systems. A survey of the band gaps of about 20 Cu-based semiconductors calculated using the mBJ + U method shows that the results agree with reliable values to within ±0.2 eV.
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
Properties of Coulomb crystals: rigorous results.
Cioslowski, Jerzy
2008-04-28
Rigorous equalities and bounds for several properties of Coulomb crystals are presented. The energy e(N) per particle pair is shown to be a nondecreasing function of the particle number N for all clusters described by double-power-law pairwise-additive potentials epsilon(r) that are unbound at both r-->0 and r-->infinity. A lower bound for the ratio of the mean reciprocal crystal radius and e(N) is derived. The leading term in the asymptotic expression for the shell capacity that appears in the recently introduced approximate model of Coulomb crystals is obtained, providing in turn explicit large-N asymptotics for e(N) and the mean crystal radius. In addition, properties of the harmonic vibrational spectra are investigated, producing an upper bound for the zero-point energy. PMID:18447485
Goree, John
then rarefactive, due to the strongly coupled crystalline state. Molecular dynamics simulations using a Yukawa of Mach cones in a crystalline Coulomb lattice (Wigner crystal), i.e., a periodic structure of repulsive predicted that boulders moving through the dust of Saturn's rings should produce Mach cones. We sustained
Towards a precise measurement of the top quark Yukawa coupling at the ILC
Juste, A.
2005-12-01
A precise measurement of the top quark Yukawa coupling is of great importance, since it may shed light on the mechanism of EWSB. We study the prospects of such measurement during the first phase of the ILC at {radical}s = 500 GeV, focusing in particular on recent theoretical developments as well as the potential benefits of beam polarization. It is shown that both yield improvements that could possibly lead to a measurement competitive with the LHC.
Thermodynamics of Thomas-Fermi screened Coulomb systems
NASA Technical Reports Server (NTRS)
Firey, B.; Ashcroft, N. W.
1977-01-01
We obtain in closed analytic form, estimates for the thermodynamic properties of classical fluids with pair potentials of Yukawa type, with special reference to dense fully ionized plasmas with Thomas-Fermi or Debye-Hueckel screening. We further generalize the hard-sphere perturbative approach used for similarly screened two-component mixtures, and demonstrate phase separation in this simple model of a liquid mixture of metallic helium and hydrogen.
Application of the Optimized Baxter Model to the hard-core attractive Yukawa system
Peter Prinsen; Josep C. Pamies; Theo Odijk; Daan Frenkel
2006-03-27
We perform Monte Carlo simulations on the hard-core attractive Yukawa system to test the Optimized Baxter Model that was introduced in [P.Prinsen and T. Odijk, J. Chem. Phys. 121, p.6525 (2004)] to study a fluid phase of spherical particles interacting through a short-range pair potential. We compare the chemical potentials and pressures from the simulations with analytical predictions from the Optimized Baxter Model. We show that the model is accurate to within 10 percent over a range of volume fractions from 0.1 to 0.4, interaction strengths up to three times the thermal energy and interaction ranges from 6 to 20 % of the particle diameter, and performs even better in most cases. We furthermore establish the consistency of the model by showing that the thermodynamic properties of the Yukawa fluid computed via simulations may be understood on the basis of one similarity variable, the stickiness parameter defined within the Optimized Baxter Model. Finally we show that the Optimized Baxter Model works significantly better than an often used, naive method determining the stickiness parameter by equating the respective second virial coefficients based on the attractive Yukawa and Baxter potentials.
A perturbative treatment for the bound states of the Hellmann potential
Sameer M. Ikhdair; Ramazan Sever
2006-03-23
A new approximation formalism is applied to study the bound states of the Hellmann potential, which represents the superposition of the attractive Coulomb potential $-a/r$ and the Yukawa potential $b\\exp (-\\delta r)/r$ of arbitrary strength $b$ and screening parameter $\\delta $. Although the analytic expressions for the energy eigenvalues $E_{n,l\\text{}}$ yield quite accurate results for a wide range of $n,\\ell $ in the limit of very weak screening, the results become gradually worse as the strength $b$ and the screening coefficient $\\delta $ increase. This is because that the expansion parameter is not sufficiently small enough to guarantee the convergence of the expansion series for the energy levels.
Renormalization group invariant of lepton Yukawa couplings
NASA Astrophysics Data System (ADS)
Tsuyuki, Takanao
2015-04-01
By using quark Yukawa matrices only, we can construct renormalization invariants that are exact at the one-loop level in the standard model. One of them, Iq, is accidentally consistent with unity, even though quark masses are strongly hierarchical. We calculate a lepton version of the invariant Il for Dirac and Majorana neutrino cases and find that Il can also be close to unity. For the Dirac neutrino and inverted hierarchy case, if the lightest neutrino mass is 3.0 meV to 8.8 meV, an equality Iq=Il can be satisfied. These invariants are not changed even if new particles couple to the standard model particles, as long as those couplings are generation independent.
Quasi-Coulomb series in a two-dimensional three-body system
Maxim A. Efremov; Wolfgang P. Schleich
2014-07-12
We show that the bound states in a three-body system display a Coulomb series with a Gaussian cut-off provided: (i) the system consists of a light particle and two heavy bosonic ones, (ii) the heavy-light short-range potential has a resonance in the $p$-wave scattering amplitude, and (iii) all three particles move in two space dimensions. For a decreasing mass ratio this quasi-Coulomb series merges into a pure Coulombic one.
Poisson's equation solution of Coulomb integrals in atoms and molecules
NASA Astrophysics Data System (ADS)
Weatherford, Charles A.; Red, Eddie; Joseph, Dwayne; Hoggan, Philip
The integral bottleneck in evaluating molecular energies arises from the two-electron contributions. These are difficult and time-consuming to evaluate, especially over exponential type orbitals, used here to ensure the correct behaviour of atomic orbitals. In this work, it is shown that the two-centre Coulomb integrals involved can be expressed as one-electron kinetic-energy-like integrals. This is accomplished using the fact that the Coulomb operator is a Green's function of the Laplacian. The ensuing integrals may be further simplified by defining Coulomb forms for the one-electron potential satisfying Poisson's equation therein. A sum of overlap integrals with the atomic orbital energy eigenvalue as a factor is then obtained to give the Coulomb energy. The remaining questions of translating orbitals involved in three and four centre integrals and the evaluation of exchange energy are also briefly discussed. The summation coefficients in Coulomb forms are evaluated using the LU decomposition. This algorithm is highly parallel. The Poisson method may be used to calculate Coulomb energy integrals efficiently. For a single processor, gains of CPU time for a given chemical accuracy exceed a factor of 40. This method lends itself to evaluation on a parallel computer.
Ion sphere model for Yukawa systems (dusty plasmas)
S. A. Khrapak; A. G. Khrapak; A. V. Ivlev; H. M. Thomas
2014-12-12
Application of the ion sphere model (ISM), well known in the context of the one-component-plasma, to estimate thermodynamic properties of model Yukawa systems is discussed. It is shown that the ISM approximation provides fairly good estimate of the internal energy of the strongly coupled Yukawa systems, in both fluid and solid phases. Simple expressions for the excess pressure and isothermal compressibility are derived, which can be particularly useful in connection to wave phenomena in strongly coupled dusty plasmas. It is also shown that in the regime of strong screening a simple consideration of neighboring particles interactions can be sufficient to obtain quite accurate estimates of thermodynamic properties of Yukawa systems.
Ion sphere model for Yukawa systems (dusty plasmas)
NASA Astrophysics Data System (ADS)
Khrapak, S. A.; Khrapak, A. G.; Ivlev, A. V.; Thomas, H. M.
2014-12-01
Application of the ion sphere model (ISM), well known in the context of the one-component-plasma, to estimate thermodynamic properties of model Yukawa systems is discussed. It is shown that the ISM approximation provides fairly good estimate of the internal energy of the strongly coupled Yukawa systems, in both fluid and solid phases. Simple expressions for the excess pressure and isothermal compressibility are derived, which can be particularly useful in connection to wave phenomena in strongly coupled dusty plasmas. It is also shown that in the regime of strong screening a simple consideration of neighboring particles interactions can be sufficient to obtain quite accurate estimates of thermodynamic properties of Yukawa systems.
Interplay between Yukawa and Tomonaga in the Birth of Mesons
Toshimitsu Yamazaki
2008-03-19
Light is shed on the early stage in the birth of Yukawa's meson theory, particularly on the interplay between Yukawa and Tomonaga in 1933. The discovery of the muon by Nishina' group in 1937 is also reviewed. It is pointed out that Heisenberg's attempt to explain the nuclear force in terms of the Heitler-London scheme, overcome by Yukawa and abandoned since then, is now being revived as a mechanism for a super strong nuclear force caused by a migrating real Kbar meson.
Jose R. Espinosa; Chee Sheng Fong; Enrico Nardi
2012-11-27
The tree level potential for a scalar multiplet of `Yukawa fields' $Y$ for one type of quarks admits the promising vacuum configuration $ \\propto {\\rm diag}(0,0,1)$ that breaks spontaneously $SU(3)_L\\times SU(3)_R$ flavour symmetry. We investigate whether the vanishing entries could be lifted to nonvanishing values by slightly perturbing the potential, thus providing a mechanism to generate the Yukawa hierarchies. For theories where at the lowest order the only massless states are Nambu-Goldstone bosons we find, as a general result, that the structure of the tree-level vacuum is perturbatively stable against corrections from scalar loops or higher dimensional operators. We discuss the reasons for this stability, and give an explicit illustration in the case of loop corrections by direct computation of the one-loop effective potential of Yukawa fields. Nevertheless, a hierarchical configuration $\\propto {\\rm diag}(\\epsilon',\\epsilon,1)$ (with $\\epsilon', \\epsilon\\ll 1$) can be generated by enlarging the scalar Yukawa sector. We present a simple model in which spontaneous breaking of the flavour symmetry can give rise to the fermion mass hierarchies.
Two body scattering length of Yukawa model on a lattice
F. De Soto; J. Carbonell; C. Roiesnel; Ph. Boucaud; J. P. Leroy; O. Pène
2006-10-13
The extraction of scattering parameters from Euclidean simulations of a Yukawa model in a finite volume with periodic boundary conditions is analyzed both in non relativistic quantum mechanics and in quantum field theory.
Lessons from All Logs Summation in Yukawa Theories
I. F. Ginzburg
2009-10-25
Some features of old results in the total summation of all logarithmic contributions of all diagrams in Yukawa theory are presented. We discuss some lessons from this picture for the description of Pomeron, odderon, etc. in QCD.
Phase diagrams of colloidal spheres with a constant zeta-potential
Frank Smallenburg; Niels Boon; Maarten Kater; Marjolein Dijkstra; René van Roij
2010-09-30
We study suspensions of colloidal spheres with a constant zeta-potential within Poisson-Boltzmann theory, quantifying the discharging of the spheres with increasing colloid density and decreasing salt concentration. We use the calculated renormalized charge of the colloids to determine their pairwise effective screened-Coulomb repulsions. Bulk phase diagrams in the colloid concentration-salt concentration representation follow, for various zeta-potentials, by a mapping onto published fits of phase boundaries of point-Yukawa systems. Although the resulting phase diagrams do feature face-centered cubic (fcc) and body-centered cubic (bcc) phases, they are dominated by the (re-entrant) fluid phase due to the colloidal discharging with increasing colloid concentration and decreasing salt concentration.
Kelvin Helmholtz Instability in Strongly Coupled Yukawa Liquids
Ashwin, J.; Ganesh, R.
2010-05-28
Using 'first principles' molecular dynamics simulations Kelvin Helmholtz instability has been observed for the first time at the particle level in two-dimensional strongly coupled Yukawa liquids. At a given coupling strength {Gamma} a subsonic shear profile is superposed on an equilibrated Yukawa liquid and instability is observed. Linear growth rates computed directly from MD simulations are seen to increase with strong coupling. Vortex-roll formation in the nonlinear regime is reported.
Dark Matter and Yukawa Unification with Massive Neutrinos
M. E. Gomez; S. Lola; P. Naranjo; J. Rodriguez-Quintero
2009-01-27
We revisit the WMAP dark matter constraints on Yukawa Unification in the presence of massive neutrinos. The large neutrino mixing indicated by the data modifies the predictions for the bottom quark mass, and enables Yukawa also for large $\\tan\\beta$, and for positive $\\mu$ that were previously disfavoured. As a result, the allowed parameter space for neutralino dark matter also increases, particularly for areas with resonant enhancement of the neutralino relic density.
Causality in 1+1 Dimensional Yukawa Model-II
Asrarul Haque; Satish D. Joglekar
2010-04-26
We discuss the limits g tending to large, M tending to large with g^3/M = const. of the 1 + 1 dimensional Yukawa model. We take into account conclusion of the results on bound states of the Yukawa Model in this limit (obtained in [7]). We find that model reduces to an effective nonlocal phi 3 theory in this limit. We observe causality violation in this limit. We discuss the result.
Kelvin Helmholtz instability in strongly coupled Yukawa liquids.
J, Ashwin; Ganesh, R
2010-05-28
Using "first principles" molecular dynamics simulations Kelvin Helmholtz instability has been observed for the first time at the particle level in two-dimensional strongly coupled Yukawa liquids. At a given coupling strength ? a subsonic shear profile is superposed on an equilibrated Yukawa liquid and instability is observed. Linear growth rates computed directly from MD simulations are seen to increase with strong coupling. Vortex-roll formation in the nonlinear regime is reported. PMID:20867109
Investigation of Coulomb dipole polarization effects on reactions involving exotic nuclei
NASA Astrophysics Data System (ADS)
Fernández-García, J. P.; Alvarez, M. A. G.; Chamon, L. C.
2015-07-01
We have analyzed elastic scattering angular distributions and total reaction cross sections of the exotic nuclei 11,9Li on 208Pb, at energies below and above the Coulomb barrier. For this purpose, we have used an optical potential with no adjustable parameters, composed by the nuclear São Paulo potential, derived from the nonlocal nature of the interaction, and the Coulomb dipole polarization potential, derived from the semiclassical theory of Coulomb excitation. Within this formalism, we identified an unusual long-range absorption for the +208Pb 11Li system, which is dominated by the Coulomb interaction. We compare it to the absorption mechanisms observed for +208Pb6He which, unlike those of +208Pb11Li, take place at small interacting distances, where both Coulomb and nuclear interactions are important. The proposed approach shows to be a fundamental basis to study reactions involving exotic nuclei.
Three-body Coulomb systems using generalized angular-momentum S states
NASA Technical Reports Server (NTRS)
Whitten, R. C.; Sims, J. S.
1974-01-01
An expansion of the three-body Coulomb potential in generalized angular-momentum eigenfunctions developed earlier by one of the authors is used to compute energy eigenvalues and eigenfunctions of bound S states of three-body Coulomb systems. The results for He, H(-), e(-)e(+)e(-), and pmu(-)p are compared with the results of other computational approaches.
Calculations for the one-dimensional soft Coulomb problem and the hard Coulomb limit.
Gebremedhin, Daniel H; Weatherford, Charles A
2014-05-01
An 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 boundaries of each element. We also 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/sqrt[x(2)+?(2)], which becomes numerically intractable (because of extreme stiffness) 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 insight into the controversial one-dimensional hydrogen atom, which is a limiting case of the soft Coulomb problem as ? ? 0. PMID:25353926
Interfacial and wetting properties of a binary point Yukawa fluid
Paul Hopkins; Andrew J. Archer; Robert Evans
2008-10-29
We investigate the interfacial phase behavior of a binary fluid mixture composed of repulsive point Yukawa particles. Using a simple approximation for the Helmholtz free energy functional, which yields the random phase approximation (RPA) for the pair direct correlation functions, we calculate the equilibrium fluid density profiles of the two species of particles adsorbed at a planar wall. We show that for a particular choice (repulsive exponential) of the wall potentials and the fluid pair-potential parameters, the Euler-Lagrange equations for the equilibrium fluid density profiles may be transformed into a single ordinary differential equation and the profiles obtained by a simple quadrature. For certain other choices of the fluid pair-potential parameters fluid-fluid phase separation of the bulk fluid is observed. We find that when such a mixture is exposed to a planar hard-wall, the fluid exhibits complete wetting on the species 2 poor side of the binodal, i.e. we observe a thick film of fluid rich in species 2 adsorbed at the hard-wall. The thickness of the wetting film grows logarithmically with the concentration difference between the fluid state-point and the binodal and is proportional to the bulk correlation length of the intruding (wetting) fluid phase. However, for state points on the binodal that are further from the critical point, we find there is no thick wetting film. We determine the accompanying line of first-order (pre-wetting) surface phase transitions which separate a thin and thick adsorbed film. We show that for some other choices of repulsive wall potentials the pre-wetting line is still present, but its location and extent in the phase diagram is strongly dependent on the wall-fluid interaction parameters.
Supersymmetric Yukawa sum rule and LHC tests
Blanke, Monika; Curtin, David; Perelstein, Maxim
2010-08-01
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.
Asymptotic safety of simple Yukawa systems
Holger Gies; Michael M. Scherer
2009-01-22
We study the triviality and hierarchy problem of a Z_2-invariant Yukawa system with massless fermions and a real scalar field, serving as a toy model for the standard-model Higgs sector. Using the functional RG, we look for UV stable fixed points which could render the system asymptotically safe. Whether a balancing of fermionic and bosonic contributions in the RG flow induces such a fixed point depends on the algebraic structure and the degrees of freedom of the system. Within the region of parameter space which can be controlled by a nonperturbative next-to-leading order derivative expansion of the effective action, we find no non-Gaussian fixed point in the case of one or more fermion flavors. The fermion-boson balancing can still be demonstrated within a model system with a small fractional flavor number in the symmetry-broken regime. The UV behavior of this small-N_f system is controlled by a conformal Higgs expectation value. The system has only two physical parameters, implying that the Higgs mass can be predicted. It also naturally explains the heavy mass of the top quark, since there are no RG trajectories connecting the UV fixed point with light top masses.
Solitons and Yukawa Couplings in Nearly Kahler Flux Compactifications
Brian P. Dolan; Richard J. Szabo
2013-08-18
We study vacuum states and symmetric fermions in equivariant dimensional reduction of Yang-Mills-Dirac theory over the six-dimensional homogeneous space SU(3)/U(1)x U(1) endowed with a family of SU(3)-structures including a nearly Kahler structure. We derive the fixed tree-level scalar potentials of the induced Yang-Mills-Higgs theory, and compute the dynamically generated gauge and Higgs boson masses as functions of the metric moduli of the coset space. We find an integrable subsector of the Higgs field theory which is governed by a sine-Gordon type model whose topological soliton solutions are determined nonperturbatively by the gauge coupling and which tunnel between families of infinitely degenerate vacua. The reduction of the Dirac action for symmetric fermions yields exactly massless chiral fermions, containing subsectors which have fixed tree-level Yukawa interactions. We compute dynamical fermion mass matrices explicitly and compare them at differents points of the moduli space, some of which support consistent heterotic flux vacua.
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.
Infrared Critical Exponents in Finite-Temperature Coulomb Gauge QCD
Klaus Lichtenegger; Daniel Zwanziger
2009-11-28
We investigate the infrared critical exponents of Coulomb gauge Yang-Mills theory in the limit of very high temperature. This allows us to focus on one scale (the spatial momentum) since all but the lowest Matsubara frequency decouple from the deep infrared. From the first-order Dyson-Schwinger equations in a bare-vertex truncation we obtain infrared exponents which correspond to confining or overconfining (yet mathematically well-defined) solutions. For three spatial dimensions the exponents are close to what is expected for a linearly rising color-Coulomb potential.
One-dimensional Coulomb problem in Dirac materials
C. A. Downing; M. E. Portnoi
2014-11-21
We investigate the one-dimensional Coulomb potential with application to a class of quasirelativistic systems, so-called Dirac-Weyl materials, described by matrix Hamiltonians. We obtain the exact solution of the shifted and truncated Coulomb problems, with the wavefunctions expressed in terms of special functions (namely Whittaker functions), whilst the energy spectrum must be determined via solutions to transcendental equations. Most notably, there are critical bandgaps below which certain low-lying quantum states are missing in a manifestation of atomic collapse.
One-dimensional Coulomb problem in Dirac materials
NASA Astrophysics Data System (ADS)
Downing, C. A.; Portnoi, M. E.
2014-11-01
We investigate the one-dimensional Coulomb potential with application to a class of quasirelativistic systems, so-called Dirac-Weyl materials, described by matrix Hamiltonians. We obtain the exact solution of the shifted and truncated Coulomb problems, with the wave functions expressed in terms of special functions (namely, Whittaker functions), while the energy spectrum must be determined via solutions to transcendental equations. Most notably, there are critical band gaps below which certain low-lying quantum states are missing in a manifestation of atomic collapse.
Coulomb versus physical string tension on the lattice
NASA Astrophysics Data System (ADS)
Burgio, Giuseppe; Quandt, Markus; Reinhardt, Hugo; Vogt, Hannes
2015-08-01
From continuum studies it is known that the Coulomb string tension ?C gives an upper bound for the physical (Wilson) string tension ?W [D. Zwanziger, Phys. Rev. Lett. 90, 102001 (2003)]. How does such a relationship translate to the lattice, however? In this paper we give evidence that on the lattice, 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 us 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.
Yukawa unification predictions for the LHC
NASA Astrophysics Data System (ADS)
Anandakrishnan, Archana; Raby, Stuart; Wingerter, Ak?n
2013-03-01
This paper is divided into two parts. In the first part 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 unification scale. 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 nine grand unification-scale parameters, while tan?? and ? are fixed at the weak scale. Good fits suggest an upper bound on the gluino mass, Mg˜?2TeV. This constraint comes predominantly from fitting the bottom-quark and Higgs masses (assuming a 125 GeV Higgs). Gluinos should be visible at the LHC in the 14 TeV run but they cannot be described by the typical simplified models. This is because the branching ratios for g˜?tt¯?˜1,20, bb¯?˜1,20, tb¯?˜1,2-, bt¯?˜1,2+, g?˜1,2,3,40 are comparable. Top squarks and sbottoms may also be visible. Charginos and neutralinos can be light, with the lightest supersymmetric particle predominantly bino-like. In the second part of the paper we analyze a complete three-family model and discuss the quality of the global ?2 fits and the differences between the third-family analysis and the full three-family analysis for overlapping observables. We note that the light Higgs in our model couples to matter like the Standard Model Higgs. Any deviation from this would rule out this model.
Test of the Stokes-Einstein relation in a two-dimensional Yukawa liquid
Bin Liu; J. Goree
2005-11-08
The Stokes-Einstein relation, relating the diffusion and viscosity coefficients D and eta, is tested in two dimensions. An equilibrium molecular-dynamics simulation was used with a Yukawa pair potential. Regimes are identified where motion is diffusive and D is meaningful. The Stokes-Einstein relation, D ~ kT, was found to be violated near the disordering transition; under these conditions collective particle motion exhibits dynamical heterogeneity. At slightly higher temperatures, however, the Stokes-Einstein relation is valid. These results may be testable in strongly-coupled dusty plasma experiments.
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.
SU(5) orientifolds, Yukawa couplings, Stringy Instantons and Proton Decay
Elias Kiritsis; Michael Lennek; Bert Schellekens
2009-09-07
We construct a large class of SU(5) orientifold vacua with tadpole cancellation both for the standard and the flipped case. We give a general analysis of superpotential couplings up to quartic order in orientifold vacua and identify the properties of needed Yukawa couplings as well as the baryon number violating couplings. We point out that successful generation of the perturbatively forbidden Yukawa couplings entails a generically disastrous rate for proton decay from an associated quartic term in the superpotential, generated from the same instanton effects. We search for the appropriate instanton effects that generate the missing Yukawa couplings in the SU(5) vacua we constructed and find them in a small subset of them.
NASA Astrophysics Data System (ADS)
Beceiro Novo, S.; Sümmerer, K.; Cortina-Gil, D.; Wimmer, C.; Plag, R.; Alvarez-Pol, H.; Aumann, T.; Behr, K.; Boretzky, K.; Casarejos, E.; Chatillon, A.; Datta-Pramanik, U.; Elekes, Z.; Fulop, Z.; Galaviz, D.; Geissel, H.; Giron, S.; Greife, U.; Hammache, F.; Heil, M.; Hoffman, J.; Johansson, H.; Karagiannis, C.; Kiselev, O.; Kurz, N.; Larsson, K.; Le Bleis, T.; Litvinov, Y.; Mahata, K.; Muentz, C.; Nociforo, C.; Ott, W.; Paschalis, S.; Prokopowicz, W.; Rodriguez-Tajes, C.; Rossi, D.; Simon, H.; Stanoiu, M.; Stroth, J.; Typel, S.; Wagner, A.; Wamers, F.; Weick, H.
2012-09-01
In this work the astrophysical 26Si(p,?)27P reaction is studied using the Coulomb dissociation technique. We performed a 27P Coulomb Dissociation experiment at GSI, Darmstadt (28 May-5 June 2007) using the ALADIN-LAND setup which allows complete-kinematic studies. A secondary 27P beam at 498 AMeV impinging a 515mg/cm2 Pb target was used. The relative energy of the outgoing system (26Si+p) is measured obtaining the resonant states of the 27P. Preliminary results show four resonant states measured at 0.36±0.07, 0.88±0.09, 1.5±0.2, 2.3±0.3 MeV and evidence of a higher state at around 3.1 MeV. The preliminary total cross section obtained for relative energies between 0 and 3 MeV has been measured and yields 55±7 mb.
The Coulomb phase shift revisited
J. C. A. Barata; L. F. Canto; M. S. Hussein
2010-05-08
We investigate the Coulomb phase shift, and derive and analyze new and more precise analytical formulae. We consider next to leading order terms to the Stirling approximation, and show that they are important at small values of the angular momentum $l$ and other regimes. We employ the uniform approximation. The use of our expressions in low energy scattering of charged particles is discussed and some comparisons are made with other approximation methods.
Nonperturbative Effects on Seven-Brane Yukawa Couplings
Marchesano, Fernando; Martucci, Luca
2010-06-11
We analyze nonperturbative corrections to the superpotential of seven-brane gauge theories on type IIB and F-theory warped Calabi-Yau compactifications. We show, in particular, that such corrections modify the holomorphic Yukawa couplings by an exponentially suppressed contribution, generically solving the Yukawa rank-one problem of certain F-theory local models. We provide explicit expressions for the nonperturbative correction to the seven-brane superpotential, and check that it is related to a noncommutative deformation to the tree-level superpotential via a Seiberg-Witten map.
Yukawa Couplings and Effective Interactions in Gauge-Higgs Unification
Yutaka Hosotani; Yoshikazu Kobayashi
2009-03-11
The wave functions and Yukawa couplings of the top and bottom quarks in the SO(5) x U(1) gauge-Higgs unification model are determined. The result is summarized in the effective interactions for \\hat \\theta_H(x) = \\theta_H + H(x)/f_H where \\theta_H is the Wilson line phase and H(x) is the 4D Higgs field. The Yukawa, WWH and ZZH couplings vanish at \\theta_H = \\onehalf \\pi. There emerges the possibility that the Higgs particle becomes stable.
Finite coulomb crystal formation
NASA Astrophysics Data System (ADS)
Vasut, J.; Hyde, T. W.; Barge, L.
2004-01-01
Dust particles immersed within a plasma environment, such as those found in planetary rings or comets, will acquire an electric charge. If the ratio of the inter-particle potential energy to average kinetic energy is large enough the particles will form either a "liquid" structure with short-range ordering or a crystalline structure with long-range ordering. Since their discovery in laboratory environments in 1994, such crystals have been the subject of a variety of experimental, theoretical and numerical investigations. Most numerical and theoretical investigations have examined infinite systems assuming periodic boundary conditions. Since experimentally observed crystals can be comprised of a few hundred particles, this often leads to discrepancies between predicted theoretical results and experimental data. In addition, recent studies have concentrated on the importance of random charge variations between individual dust particles, but very little on the importance of size variations between the grains. Such size variations naturally lead to inter-grain charge variations which can easily become more important than those due to random charge fluctuations (which are typically less than one percent). Although such size variations can be largely eliminated experimentally by introducing mono-dispersive particles, many laboratory systems and all astrophysical environments contain significant size distributions. This study utilizes a program to find the equilibrium positions of a dusty plasma system as well as a modified Barnes-Hut code to model the dynamic behavior of such systems. It is shown that in terms of inter-particle spacing and ordering, finite systems are significantly different than infinite ones, particularly for the most-highly ordered states.
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.
Fluid approach to evaluate sound velocity in Yukawa systems and complex plasmas
NASA Astrophysics Data System (ADS)
Khrapak, Sergey A.; Thomas, Hubertus M.
2015-03-01
The conventional fluid description of multicomponent 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 quasilocalized 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.
Fluid approach to evaluate sound velocity in Yukawa systems and complex plasmas.
Khrapak, Sergey A; Thomas, Hubertus M
2015-03-01
The conventional fluid description of multicomponent 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 quasilocalized 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. PMID:25871227
(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
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-Bing Cheng Li-Tien Cheng Bo Li October 10, 2011 Abstract A Yukawa-field approximation of the electrostatic the molecular conformation, stability, and dynamics. An explicit formula of such forces with the Yukawa
Yu.V. Kalyuzhnyi, S.P. Hlushak PHASE COEXISTENCE IN POLYDISPERSE MULTI-YUKAWA
MULTI-YUKAWA HARD-SPHERE FLUID ICMP0410E I : 532; 532.74; 532.772 PACS: 05.70.Ce; 61.20.Gy; 82.70.Dd in polydisperse multi-Yukawa hard-sphere fluid Yu.V. Kalyuzhnyi, S.P. Hlushak Abstract. Polydisperse multi-Yukawa
PHYSICAL REVIEW E 88, 063103 (2013) Collisional and collisionless expansion of Yukawa balls
Goree, John
2013-01-01
PHYSICAL REVIEW E 88, 063103 (2013) Collisional and collisionless expansion of Yukawa balls; published 10 December 2013) The expansion of Yukawa balls is studied by means of molecular dynamics the parallel computing power of graphics processing units. When the radius of the Yukawa ball is large compared
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)
Renormalization of the Yukawa Theory Physics 230A (Spring 2007), Hitoshi Murayama
Murayama, Hitoshi
Renormalization of the Yukawa Theory Physics 230A (Spring 2007), Hitoshi Murayama We solve Problem,s the number of fermion or scalar propagators, respectively, and VY the number of Yukawa vertices. Since each Yukawa vertex comes with two fermion lines and one scalar line, VY = 1 2 (2Pf + Nf ) = 2Ps + Ns. (6) Here
Shear viscosity and shear thinning in two-dimensional Yukawa , J. Goree2
Goree, John
Shear viscosity and shear thinning in two-dimensional Yukawa liquids Z. DonkÂ´o1 , J. Goree2 , P of Iowa, Iowa City, Iowa 52242, USA (March 22, 2006) Abstract A two-dimensional Yukawa liquid is studied will exhibit this effect. Typeset using REVTEX 1 #12;Many-particle systems characterized by the Yukawa
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 information such as the triviality property of the Higgs- Yukawa sector or indirect arguments like vacuum-perturbative investigation of a chirally invariant lattice Higgs-Yukawa model, serving here as a reasonable simplification
On the phase structure of a chiral invariant Higgs-Yukawa model
On the phase structure of a chiral invariant Higgs-Yukawa model Philipp Gerholda Karl Jansenb Higgs-Yukawa model Â p.1/18 #12;Organization of the talk Â· 1. Introduction and motivation Â· 2. The model On the phase structure of a chiral invariant Higgs-Yukawa model Â p.2/18 #12;1. Introduction and motivation
Spectroscopy as a test of Coulomb's law: A probe of the hidden sector
NASA Astrophysics Data System (ADS)
Jaeckel, Joerg; Roy, Sabyasachi
2010-12-01
High precision spectroscopy can provide a sensitive tool to test Coulomb’s law on atomic length scales. This can then be used to constrain particles such as extra “hidden” photons or minicharged particles that are predicted in many extensions of the standard model, and which cause small deviations from Coulomb’s law. In this paper we use a variety of transitions in atomic hydrogen, hydrogenic ions, and exotic atoms to probe Coulomb’s law. This extends the region of pure Coulomb’s law tests to larger masses. For hidden photons and minicharged particles this region is already tested by other astrophysical and laboratory probes. However, future tests of true muonium and muonic atoms are likely to probe new parameter space and therefore have good discovery potential for new physics. Finally, we investigate whether the discrepancy between the theoretical calculation of the 2s1/2F=1-2p3/2F=2 transition in muonic hydrogen and its recent experimental measurement at PSI can be explained by the existence of a hidden photon. This explanation is ruled out by measurements of the Lamb shift in ordinary hydrogen.
Coulomb-interacting billiards in circular cavities
NASA Astrophysics Data System (ADS)
Solanpää, J.; Nokelainen, J.; Luukko, P. J. J.; Räsänen, E.
2013-06-01
We apply a molecular dynamics scheme to analyze classically chaotic properties of a two-dimensional circular billiard system containing two Coulomb-interacting electrons. As such, the system resembles a prototype model for a semiconductor quantum dot. The interaction strength is varied from the noninteracting limit with zero potential energy up to the strongly interacting regime where the relative kinetic energy approaches zero. At weak interactions the bouncing maps show jumps between quasi-regular orbits. In the strong-interaction limit we find an analytic expression for the bouncing map. Its validity in the general case is assessed by comparison with our numerical data. To obtain a more quantitative view on the dynamics as the interaction strength is varied, we compute and analyze the escape rates of the system. Apart from very weak or strong interactions, the escape rates show consistently exponential behavior, thus suggesting strongly chaotic dynamics and a phase space without significant sticky regions within the considered time scales.
Coulomb disorder in three-dimensional Dirac materials
NASA Astrophysics Data System (ADS)
Skinner, Brian
2015-03-01
In three-dimensional materials with a Dirac spectrum, weak short-ranged disorder is essentially irrelevant near the Dirac point. This is manifestly not the case for Coulomb disorder, where the long-ranged nature of the potential produced by charged impurities implies large fluctuations of the disorder potential even when impurities are sparse, and these fluctuations are screened by the formation of electron/hole puddles. Here I outline a theory of such nonlinear screening of Coulomb disorder in three-dimensional Dirac systems, and present results for the typical magnitude of the disorder potential, the corresponding density of states, and the size and density of electron/hole puddles. The resulting conductivity is also discussed.
An Exact Solution to the Yukawa System in Four Dimensions
T. Mark Harder; Thomas K. DeLillo
2010-06-20
An exact, closed form solution to the scalar Yukawa system in four dimensions is presented. The formalism is used to state and prove a theorem on the initial value problem. The method also works for a general, iso-vector form of the interacting system. We close with some comments on the quantum version of this problem.
Dynamical symmetry breaking in models with the Yukawa interaction
Ksenzov, V. G. [State Scientific Center Institute for Theoretical and Experimental Physics (Russian Federation)] [State Scientific Center Institute for Theoretical and Experimental Physics (Russian Federation); Romanov, A. I. [National Research Nuclear University MEPhI (Russian Federation)] [National Research Nuclear University MEPhI (Russian Federation)
2013-04-15
The models with a massless fermion and a self-interacting massive scalar field with the Yukawa interaction are discussed. The chiral condensate and the fermion mass are calculated analytically through a one-loop approximation in (1 + 1)-dimensions. It is shown that the models have a phase transition as a function of the squared mass of the scalar field.
Gravitational corrections to Yukawa and phi{4} interactions.
Rodigast, Andreas; Schuster, Theodor
2010-02-26
We consider the lowest order quantum gravitational corrections to Yukawa and phi{4} interactions. Our results show that quantum gravity leads to contributions to the running coupling constants if the particles are massive and therefore alters the scaling behavior of the standard model. Furthermore, we find that the gravitational contributions to the running of the masses vanish. PMID:20366925
Gravitational Corrections to Yukawa and phi{sup 4} Interactions
Rodigast, Andreas; Schuster, Theodor
2010-02-26
We consider the lowest order quantum gravitational corrections to Yukawa and phi{sup 4} interactions. Our results show that quantum gravity leads to contributions to the running coupling constants if the particles are massive and therefore alters the scaling behavior of the standard model. Furthermore, we find that the gravitational contributions to the running of the masses vanish.
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.
Dynamical Symmetry Breaking in Models with the Yukawa Interaction
V. G. Ksenzov; A. I. Romanov
2012-04-19
We discuss models with a massless fermion and a self-interacting massive scalar field with the Yukawa interaction. The chiral condensate and the fermion mass are calculated analytically. It is shown that the models have a phase transition as a function of the squared mass of the scalar field.
Practical thermodynamics of Yukawa systems at strong coupling.
Khrapak, Sergey A; Kryuchkov, Nikita P; Yurchenko, Stanislav O; Thomas, Hubertus M
2015-05-21
Simple practical approach to estimate thermodynamic properties of strongly coupled Yukawa systems, in both fluid and solid phases, is presented. The accuracy of the approach is tested by extensive comparison with direct computer simulation results (for fluids and solids) and the recently proposed shortest-graph method (for solids). Possible applications to other systems of softly repulsive particles are briefly discussed. PMID:26001480
Practical thermodynamics of Yukawa systems at strong coupling
Sergey A. Khrapak; Nikita P. Kryuchkov; Stanislav O. Yurchenko; Hubertus M. Thomas
2015-05-20
Simple practical approach to estimate thermodynamic properties of strongly coupled Yukawa systems, in both fluid and solid phases, is presented. The accuracy of the approach is tested by extensive comparison with direct computer simulation results (for fluids and solids) and the recently proposed shortest-graph method (for solids). Possible applications to other systems of softly repulsive particles are briefly discussed.
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.
Yukawa model on a lattice: two body states
F. De Soto; J. Carbonell; C. Roiesnel; Ph. Boucaud; J. P. Leroy; O. Pène
2006-10-13
We present first results of the solutions of the Yukawa model as a Quantum Field Theory (QFT) solved non perturbatively with the help of lattice calculations. In particular we will focus on the possibility of binding two nucleons in the QFT, compared to the non relativistic result.
Yukawa's Pion, Low-Energy QCD and Nuclear Chiral Dynamics
Wolfram Weise
2007-04-16
A survey is given of the evolution from Yukawa's early work, via the understanding of the pion as a Nambu-Goldstone boson of spontaneously broken chiral symmetry in QCD, to modern developments in the theory of the nucleus based on the chiral effective field theory representing QCD in its low-energy limit.
On the phase structure of a chiral invariant Higgs-Yukawa model
Philipp Gerhold; Karl Jansen
2007-01-09
In the past the construction of Higgs-Yukawa models on the lattice was blocked by the lack of a consistent definition of a chiral invariant Yukawa coupling term. Here, we consider a chiral invariant Higgs-Yukawa model based on the overlap operator, realized by the Neuberger-Dirac operator. As a first step towards a numerical examination of this model we study its phase diagram by means of an analytic 1/N-expansion, which is possible for small and for large values of the Yukawa coupling constant. In the case of strong Yukawa couplings the model effectively becomes an O(4)-symmetric non-linear sigma-model.
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).
Coulomb force as an entropic force
NASA Astrophysics Data System (ADS)
Wang, Tower
2010-05-01
Motivated by Verlinde’s theory of entropic gravity, we give a tentative explanation to the 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.
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.
Lee, C. M. E-mail: apkschan@cityu.edu.hk; Chan, K. S. E-mail: apkschan@cityu.edu.hk
2014-07-28
Employing numerical diagonalization, we study the optical properties of an electron in a monolayer-graphene magnetic dot bound to an off-center negatively charged Coulomb impurity based on the massless Dirac-Weyl model. Numerical results show that, since the electron-hole symmetry is broken by the Coulomb potential, the optical absorption spectra of the magnetic dot in the presence of a Coulomb impurity are different between the electron states and the hole states. Effects of both the magnetic field and the dot size on the absorption coefficient are presented as functions of the incident photon energies.
Unified analysis of multipole and finite-mass corrections in long-range Coulombic interactions
NASA Technical Reports Server (NTRS)
Au, C. K.
1988-01-01
Simple expressions are derived for all multipole nonadiabatic and finite-nuclear-mass corrections to the long-range effective potential due to two-Coulomb-photon exchange at threshold energy, and also for first-order energy corrections for the scattering between a spinles point charged particle and a spinless Coulombic complex and between two spinless Coulombic complexes. All these corrections are treated on equal footing, and the results are expressed, respectively, in terms of single-center and London-analog two-center atomic-multipole spectral sums.
Quantum solution for the one-dimensional Coulomb problem
Nunez-Yepez, H. N.; Salas-Brito, A. L.; Solis, Didier A.
2011-06-15
The one-dimensional hydrogen atom has been a much studied system with a wide range of applications. Since the pioneering work of Loudon [R. Loudon, Am. J. Phys. 27, 649 (1959).], a number of different features related to the nature of the eigenfunctions have been found. However, many of the claims made throughout the years in this regard are not correct--such as the existence of only odd eigenstates or of an infinite binding-energy ground state. We explicitly show that the one-dimensional hydrogen atom does not admit a ground state of infinite binding energy and that the one-dimensional Coulomb potential is not its own supersymmetric partner. Furthermore, we argue that at the root of many such false claims lies the omission of a superselection rule that effectively separates the right side from the left side of the singularity of the Coulomb potential.
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.
Probing Minicharged Particles with Tests of Coulomb's Law
Joerg Jaeckel
2009-04-09
Minicharged particles arise in many extensions of the Standard Model. Their contribution to the vacuum polarization modifies Coulomb's law via the Uehling potential. In this note we argue that tests for electromagnetic fifth forces can therefore be a sensitive probe of minicharged particles. In the low mass range <~micro-eV existing constraints from Cavendish type experiments provide the best model-independent bounds on minicharged particles.
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
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.
NASA Astrophysics Data System (ADS)
Gabrielli, Emidio; Raidal, Martti
2014-01-01
We propose a new paradigm for generating exponentially spread standard model Yukawa couplings from a new U(1)F gauge symmetry in the dark sector. Chiral symmetry is spontaneously broken among dark fermions that obtain nonvanishing masses from a nonperturbative solution to the mass gap equation. The necessary ingredient for this mechanism to work is the existence of higher-derivative terms in the dark U(1)F theory, or equivalently the existence of Lee-Wick ghosts, that (i) allow for a nonperturbative solution to the mass gap equation in the weak coupling regime of the Abelian theory and (ii) induce exponential dependence of the generated masses on dark fermion U(1)F quantum numbers. The generated flavor and chiral symmetry breaking in the dark sector is transferred to the standard model Yukawa couplings at the one-loop level via Higgs portal-type scalar messenger fields. The latter carry quantum numbers of squarks and sleptons. A new intriguing phenomenology is predicted that could be potentially tested at the LHC, provided the characteristic mass scale of the messenger sector is accessible at the LHC as is suggested by naturalness arguments.
Gabrielli, Emidio
2014-01-01
We propose a new paradigm for generating exponentially spread standard model Yukawa couplings from a new $U(1)_F$ gauge symmetry in the dark sector. Chiral symmetry is spontaneously broken among dark fermions that obtain non-vanishing masses from a non-perturbative solution to the mass gap equation. The necessary ingredient for this mechanism to work is the existence of higher derivative terms in the dark $U(1)_F$ theory, or equivalently the existence of Lee-Wick ghosts, that (i) allow for a non-perturbative solution to the mass gap equation in the weak coupling regime of the Abelian theory; (ii) induce exponential dependence of the generated masses on dark fermion $U(1)_F$ quantum numbers. The generated flavor and chiral symmetry breaking in the dark sector is transferred to the standard model Yukawa couplings at one loop level via Higgs portal type scalar messenger fields. The latter carry quantum numbers of squarks and sleptons. A new intriguing phenomenology is predicted that could be potentially tested a...
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).
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.
Yukawa unification and sparticle spectroscopy in gauge mediation models
NASA Astrophysics Data System (ADS)
Gogoladze, Ilia; Mustafayev, Azar; Shafi, Qaisar; Ün, Cem Salih
2015-05-01
We explore the implications of the t -b -? (and b -? ) Yukawa coupling unification condition on the fundamental parameter space and sparticle spectroscopy in the minimal gauge mediated supersymmetry breaking model. We find that this scenario prefers values of the C P -odd Higgs mass mA?1 TeV , with all colored sparticle masses above 3 TeV. These predictions will be hard to test at LHC13 but they may be testable at the high-energy LHC (HE-LHC) 33 TeV or a 100 TeV collider. Both the t -b -? and the b -? Yukawa coupling unification prefer a relatively light gravitino with mass ?30 eV , which makes it a candidate hot dark matter particle. However, it cannot account for more than 15% of the observed dark matter density.
Effective Hamiltonian for bound states in Yukawa theory
Weber, Axel
2013-07-15
A generalization of the Gell-Mann–Low theorem is applied to lowest nontrivial order to determine an effective Hamiltonian for two-fermion states in relativistic Yukawa theory. The consistency of the corresponding effective Schrödinger equation is thoroughly investigated in various aspects, among others the nonrelativistic and one-body limits, and the small-distance or large-momentum regime of the bound state solutions is discussed in detail. -- Highlights: •A generalization of the Gell-Mann–Low theorem is applied to Yukawa theory. •The effective Hamiltonian for two-fermion states is derived to lowest order. •The nonrelativistic and one-body limits are consistent. •The large-momentum behavior of the bound-state solutions is analyzed. •A critical value for the coupling constant is determined.
Non-renormalizable Yukawa Interactions and Higgs Physics
Z. Murdock; S. Nandi; Santosh Kumar Rai
2010-10-07
We explore a scenario in the Standard Model in which dimension four Yukawa couplings are either forbidden by a symmetry, or happen to be very tiny, and the Yukawa interactions are dominated by effective dimension six interactions. In this case, the Higgs interactions to the fermions are enhanced in a large way, whereas its interaction with the gauge bosons remains the same as in the Standard Model. In hadron colliders, Higgs boson production via gluon gluon fusion increases by a factor of nine. Higgs decay widths to fermion anti-fermion pairs also increase by the same factor, whereas the decay widths to photon photon and gamma Z are reduced. Current Tevatron exclusion range for the Higgs mass increases to ~ 142-200 GeV in our scenario, and new physics must appear at a scale below a TeV.
Large-N_f chiral transition in the Yukawa model
Sergio Caracciolo; Bortolo Matteo Mognetti; Andrea Pelissetto
2006-01-14
We investigate the finite-temperature behavior of the Yukawa model in which $N_{f}$ fermions are coupled with a scalar field $\\phi$ in the limit $N_f \\to \\infty$. Close to the chiral transition the model shows a crossover between mean-field behavior (observed for $N_f = \\infty$) and Ising behavior (observed for any finite $N_f$). We show that this crossover is universal and related to that observed in the weakly-coupled $\\phi^4$ theory. It corresponds to the renormalization-group flow from the unstable Gaussian fixed point to the stable Ising fixed point. This equivalence allows us to use results obtained in field theory and in medium-range spin models to compute Yukawa correlation functions in the crossover regime.
Effects of supersymmetric threshold corrections on the Yukawa matrix unification
NASA Astrophysics Data System (ADS)
Iskrzy?ski, Mateusz
2015-02-01
We present an updated analysis of the Yukawa matrix unification within the renormalizable R-parity-conserving Minimal Supersymmetric Standard Model. It is assumed that the soft terms are non-universal but flavour-diagonal in the super-CKM basis at the GUT scale. Trilinear Higgs-squark-squark -terms can generate large threshold corrections to the Yukawa matrix at the superpartner decoupling scale. In effect, the boundary condition at the GUT scale can be satisfied. However, such large trilinear terms make the usual Higgs vacuum metastable (though long-lived). We broaden previous studies by including results from the first LHC phase, notably the measurement of the Higgs particle mass, as well as a quantitative investigation of flavour observables.
Why should we care about the top quark Yukawa coupling?
Shapshnikov, Mikhail; Bezrukov, Fedor
2015-03-01
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. We overview the most recent theoretical computations of and the experimental measurements of ytcrit and the experimental measurements of yt. Within themore »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
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.
Defect Fluctuations and Lifetimes in Disordered Yukawa Systems
C. Reichhardt; C. J. Olson Reichhardt
2007-03-01
We examine the time dependent defect fluctuations and lifetimes for a bidisperse disordered assembly of Yukawa particles. At high temperatures, the noise spectrum of fluctuations is white and the coordination number lifetimes have a stretched exponential distribution. At lower temperatures, the system dynamically freezes, the defect fluctuations exhibit a 1/f spectrum, and there is a power law distribution of the coordination number lifetimes. Our results indicate that topological defect fluctuations may be a useful way to characterize systems exhibiting dynamical heterogeneities.
Fourth Generation -- Towards Effect of Large Yukawa Coupling
George W. S. Hou
2010-07-14
In this talk we cover two threads regarding the 4th generation: on CP violation, from Earth up to the Heavens, i.e. from accelerator-based experimental studies, towards baryon asymmetry of the Universe; and on direct search bounds on $m_{t'}$ and $m_{b'}$, towards the possibility of electroweak symmetry breaking through large Yukawa couplings. Prospects and discussions are presented.
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.
Nonstandard Yukawa Couplings and Higgs Portal Dark Matter
Fady Bishara; Joachim Brod; Patipan Uttayarat; Jure Zupan
2015-05-15
We study the implications of non-standard Higgs Yukawa couplings to light quarks on Higgs-portal dark matter phenomenology. Saturating the present experimental bounds on up-quark, down-quark, or strange-quark Yukawa couplings, the predicted direct dark matter detection scattering rate can increase by up to four orders of magnitude. The effect on the dark matter annihilation cross section, on the other hand, is subleading unless the dark matter is very light -- a scenario that is already excluded by measurements of the Higgs invisible decay width. We investigate the expected size of corrections in multi-Higgs-doublet models with natural flavor conservation, the type-II two-Higgs-doublet model, the Giudice-Lebedev model of light quark masses, minimal flavor violation new physics models, Randall-Sundrum, and composite Higgs models. We find that an enhancement in the dark matter scattering rate of an order of magnitude is possible. Finally, we point out that a discovery of Higgs-portal dark matter could lead to interesting bounds on the light-quark Yukawa couplings.
Yukawa unification: The good, the bad, and the ugly
Rattazzi, R. [Rutgers Univ., Piscataway, NJ (United States). Dept. of Physics and Astronomy; Sarid, U. [Stanford Univ., Stanford, CA (United States). Dept. of Physics; Hall, L.J. [Lawrence Berkeley Lab., CA (United States)
1993-05-01
We analyze some consequences of grand unification of the third-generation Yukawa couplings, in the context of the minimal supersymmetric standard model. We address two issues: the prediction of the top quark mass, and the generation of the top-bottom mass hierarchy through a hierarchy of Higgs vacuum expectation values. The top mass is strongly dependent on a certain ratio of superpartner masses. And the VEV hierarchy always entails some tuning of the GUT-scale parameters. We study the RG equations and their semi-analytic solutions, which exhibit several interesting features, such as a focusing effect for a large Yukawa coupling in the limit of certain symmetries and a correlation between the A terms (which contribute to b {yields} s{gamma}) and the gaugino masses. This study shows that non-universal soft-SUSY-breaking masses are favored (in particular for splitting the Higgs-doublets via D-terms and for allowing more natural scenarios of symmetry breaking), and hints at features desired in Yukawa-unified models. Several phenomenological implications are also revealed.
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.
Relativistic Coulomb scattering of spinless bosons
NASA Astrophysics Data System (ADS)
Garcia, M. G.; de Castro, A. S.
2015-03-01
The relativistic scattering of spin-0 bosons by spherically symmetric Coulomb fields is analyzed in detail with an arbitrary mixing of vector and scalar couplings. It is shown that the partial wave series reduces the scattering amplitude to the closed Rutherford formula exactly when the vector and scalar potentials have the same magnitude, and as an approximation for weak fields. The behavior of the scattering amplitude near the conditions that furnish its closed form is also discussed. Strong suppressions of the scattering amplitude when the vector and scalar potentials have the same magnitude are observed either for particles or antiparticles with low incident momentum. We point out that such strong suppressions might be relevant in the analysis of the scattering of fermions near the conditions for the spin and pseudospin symmetries. From the complex poles of the partial scattering amplitude the exact closed forms of bound-state solutions for both particles and antiparticles with different scenarios for the coupling constants are obtained. Perturbative breaking of the accidental degeneracy appearing in a pair of special cases is related to the nonconservation of the Runge-Lenz vector.
Coulomb impurity problem of graphene in magnetic fields
Kim, S C
2014-01-01
Analytical solutions of the Coulomb impurity problem of graphene in the absence of a magnetic field show that when the dimensionless strength of the Coulomb potential $g$ reaches a critical value the solutions become supercritical with imaginary eigenenergies. Application of a magnetic field is a singular perturbation, and no analytical solutions are known except at a denumerably infinite set of magnetic fields. We find solutions of this problem by numerical diagonalization of large Hamiltonian matrices. Solutions are qualitatively different from those of zero magnetic field. All energies are discrete and no complex energies allowed. We have computed the finite-size scaling function of the probability density containing s-wave component of Dirac wavefunctions. This function depends on the coupling constant, regularization parameter, and the gap. In the limit of vanishing regularization parameter our findings are consistent with the expected values exponent $\
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.
Probing wrong-sign Yukawa couplings at the LHC and a future linear collider
California at Santa Cruz, University of
Probing wrong-sign Yukawa couplings at the LHC and a future linear collider P. M. Ferreira* and Rui- Higgs mass allowed by tree-level unitarity bounds when the b-quark Yukawa coupling has the opposite sign possibility of a sign change in one of the Higgs Yukawa couplings, hD for down-type fermions or hU for up
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.
Totsuji, Hiroo
2008-07-15
The thermodynamics is analyzed for a system composed of particles with hard cores, interacting via the repulsive Yukawa potential (Yukawa particulates), and neutralizing ambient (background) plasma. An approximate equation of state is given with proper account of the contribution of ambient plasma and it is shown that there exists a possibility for the total isothermal compressibility of Yukawa particulates and ambient plasma to diverge when the coupling between Yukawa particulates is sufficiently strong. In this case, the system undergoes a transition into separated phases with different densities and we have a critical point for this phase separation. Examples of approximate phase diagrams related to this transition are given. It is emphasized that the critical point can be in the solid phase and we have the possibility to observe a solid-solid phase separation. The applicability of these results to fine particle plasmas is investigated. It is shown that, though the values of the characteristic parameters are semiquantitative due to the effects not described by this model, these phenomena are expected to be observed in fine particle plasmas, when approximately isotropic bulk systems are realized with a very strong coupling between fine particles.
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.
Scalar mass stability bound in a simple Yukawa-theory from renormalisation group equations
Jakovac, A; Patkos, A
2015-01-01
Functional Renormalisation Group equations are constructed for a simple fermion-scalar Yukawa-model with discrete chiral symmetry, including also the effect of a nonzero composite fermion background beyond the conventional scalar condensate. Two approximate versions consistent with the scale dependent equations of motion are solved, taking into account also field renormalisation. The lower bound for the mass of the scalar field is determined requiring the stability of effective potential in the full momentum range, from the cutoff down to vanishing momentum. Close agreement is demonstrated with the results of previous studies done exclusively in presence of scalar condensate. A semiquantitative explanation is provided both for the negligible effect of the wave-function renormalisation and the narrow dispersion in the scalar mass bounds found from different approximation schemes.
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.
Martial Mazars
2008-10-24
We present a study of the structural properties of the crystalline phases for a planar bilayer of particles interacting via repulsive Yukawa potentials in the weak screening region. The study is done with Monte Carlo computations and the long ranged contributions to energy are taken into account with the Ewald method for quasi-two dimensional systems. Two first order phase transitions (fluid-solid and solid-solid) and one second order transition (solid-solid) are found when the surface density is varied at constant temperature. A particular attention is pay to the characteristics of the crystalline phases by the analysis of bond orientational order parameters and center-to-center correlations functions.
Beaumel, D.; Blumenfeld, Y.; Fortier, S.; Frascaria, N.; Lima, V.; Gibelin, J.; Motobayashi, T.; Aoi, N.; Baba, H.; Fukuda, N.; Gomi, T.; Kubo, T.; Takeuchi, S.; Yanagisawa, Y.; Yoshida, K.; Elekes, Z.; Ishikawa, K.; Kondo, Y.; Nakamura, T.; Satou, Y.
2007-02-26
Coulomb excitation of the exotic neutron-rich nucleus 26Ne on a 208Pb target was measured at 58 A.MeV in order to search for low-lying E1 strength above the neutron emission threshold. Data were also taken on an Al target to estimate the nuclear contribution. The radioactive beam was produced by fragmentation of a 95 A.MeV Ar beam delivered by the RIKEN Research Facility. The set-up included a NaI gamma-ray array, a charged fragment hodoscope and a neutron wall. Using the invariant mass method in the 25Ne+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV excitation energy. By performing a multipole decomposition of the differential cross-section, a reduced dipole transition probability of B(E1)=0.49{+-}0.16 e2fm2 is deduced. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is measured.
Laser Coulomb explosion imaging of molecular dynamics
NASA Astrophysics Data System (ADS)
Bocharova, Irina A.
2009-11-01
The goal of this dissertation project was to study the dynamics of nuclear motion in diatomic (H2, N2, O2, CO) and triatomic (CO2) molecules initiated by the ionization and/or excitation of these molecules with near-IR few-cycle laser pulses. This dynamics includes vibrational and rotational motion on the electronic potential surfaces of the molecules and their molecular ions. The experimental techniques used included the pump-probe approach, laser Coulomb explosion imaging and the COLTRIMS technique. The results are presented in four chapters. A study of rotational and vibrational nuclear dynamics in H2 and D2 molecules and ions initiated by 8 fs near-IR pulses is presented in Chapter 4. Transient alignment of the neutral molecules was observed and simulated; rotational frequency components contributing to the rotational wavepacket dynamics were recovered. Chapter 5 is dedicated to revealing the contribution of excited dissociative states of D2+ ions to the process of fragmentation by electron recollision. It was shown that it is possible to isolate the process of resonant excitation and estimate the individual contributions of the 2Sigmau+ and 2? u states. In Chapter 6 the subject of investigation is the nuclear dynamics of N2, O2 and CO molecules initiated by ionization of a neutral molecule by a short intense laser pulse. It was shown that the kinetic energy release of the Coulomb explosion fragments, measured as a function of the delay time between pump and probe pulses, reveals the behavior of nuclear wave packet evolution on electronic states of the molecular ions. It was shown that information on the dissociation and excitation pathways can be extracted from the experimental spectra and the relative contributions of particular electronic states can be estimated. Chapter 7 is focused on studying the fragmentation of CO2 following the interaction of this molecule with the laser field. The most important result of this study was that it presented direct experimental evidence of charge-resonant enhanced ionization (CREI), a phenomenon well-studied for diatomic molecules and predicted theoretically for triatomic molecules. The critical internuclear distance, the relevant ionic charge state and a pair of charge-resonant states responsible for the CREI were also found.
Modelling Coulomb Collisions in Anisotropic Plasmas
NASA Astrophysics Data System (ADS)
Hellinger, P.; Travnicek, P. M.
2009-12-01
Collisional transport in anisotropic plasmas is investigated comparing the theoretical transport coefficients (Hellinger and Travnicek, 2009) for anisotropic particles with the results of the corresponding Langevin equation, obtained as a generalization of Manheimer et al. (1997). References: Hellinger, P., and P. M. Travnicek (2009), On Coulomb collisions in bi-Maxwellian plasmas, Phys. Plasmas, 16, 054501. Manheimer, W. M., M. Lampe and G. Joyce (1997), Langevin representation of Coulomb collisions in PIC simulations, J. Comput. Phys., 138, 563-584.
Scattering states of Dirac equation in the presence of cosmic string for Coulomb interaction
NASA Astrophysics Data System (ADS)
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.
Diffusion coefficient of three-dimensional Yukawa liquids
Dzhumagulova, K. N.; Ramazanov, T. S.; Masheeva, R. U. [IETP, Al Farabi Kazakh National University, 71, al Farabi ave., Almaty 050040 (Kazakhstan)] [IETP, Al Farabi Kazakh National University, 71, al Farabi ave., Almaty 050040 (Kazakhstan)
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.
Collective modes of quasi-two-dimensional Yukawa liquids.
Donkó, Z; Hartmann, P; Kalman, G J
2004-06-01
Particles in dusty plasmas are often confined to a quasi-two-dimensional arrangement. In such layers--besides the formation of compressional and (in-plane) shear waves--an additional collective excitation may also show up, as small-amplitude oscillations of the particles perpendicular to the plane are also possible. We explore through molecular dynamics simulations the properties (fluctuation spectra, dispersion relation, Einstein frequency) of this out-of-plane transverse mode in the strongly coupled liquid phase of Yukawa systems. PMID:15244656
Probing the Charm Yukawa Coupling in Higgs + Charm Production
Ilaria Brivio; Florian Goertz; Gino Isidori
2015-07-10
We propose a new method to determine the coupling of the Higgs boson to charm quarks, via Higgs production in association with a charm-tagged jet: $pp\\to hc$. 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 SM value of the charm Yukawa coupling. As a byproduct of this analysis, we present an estimate of the exclusive $pp \\to hD^{(*)}$ electroweak cross section. Within the SM, the latter turns out to be not accessible at the LHC even in the high-luminosity phase.
One-loop Yukawa Couplings in Local Models
Joseph P. Conlon; Mark Goodsell; Eran Palti
2010-07-29
We calculate the one-loop Yukawa couplings and threshold corrections for supersymmetric local models of branes at singularities in type IIB string theory. We compute the corrections coming both from wavefunction and vertex renormalisation. The former comes in the IR from conventional field theory running and in the UV from threshold corrections that cause it to run from the winding scale associated to the full Calabi-Yau volume. The vertex correction is naively absent as it appears to correspond to superpotential renormalisation. However, we find that while the Wilsonian superpotential is not renormalised there is a physical vertex correction in the 1PI action associated to light particle loops.
Probing the Charm Yukawa Coupling in Higgs + Charm Production
Brivio, Ilaria; Isidori, Gino
2015-01-01
We propose a new method to determine the coupling of the Higgs boson to charm quarks, via Higgs production in association with a charm-tagged jet: $pp\\to hc$. 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 SM value of the charm Yukawa coupling. As a byproduct of this analysis, we present an estimate of the exclusive $pp \\to hD^{(*)}$ electroweak cross section. Within the SM, the latter turns out to be not accessible at the LHC even in the high-luminosity phase.
On the contribution of plasminos to the shear viscosity of a hot and dense Yukawa-Fermi gas
Sadooghi, N
2015-01-01
Using the standard Green-Kubo formalism, we determine the shear viscosity $\\eta$ of a hot and dense Yukawa-Fermi gas. In particular, we study the effect of particle and plasmino excitations on thermal properties of the fermionic part of the shear viscosity, and explore the effects of thermal corrections to particle masses on bosonic and fermionic shear viscosities, $\\eta_b$ and $\\eta_f$. It turns out that the effects of plasminos on $\\eta_f$ become negligible with increasing (decreasing) temperature (chemical potential).
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
Wu, Jianzhong
A self-consistent approach for modelling the interfacial properties and phase diagrams of Yukawa the phase behaviour and interfacial tensions of van der Waals fluids represented by the hard-core Yukawa
Testing the SUSY-QCD Yukawa coupling in a combined LHC/ILC analysis
Freitas, A
2007-01-01
In order to establish supersymmetry (SUSY) at future colliders, the identity of gauge couplings and the corresponding Yukawa couplings between gauginos, sfermions and fermions needs to be verified. Here a first phenomenological study for determining the Yukawa coupling of the SUSY-QCD sector is presented, using a method which combines information from LHC and ILC.
Practical expressions for the internal energy and pressure of Yukawa fluids
NASA Astrophysics Data System (ADS)
Khrapak, Sergey A.; Thomas, Hubertus M.
2015-02-01
Simple practical expressions that allow estimation of thermodynamic properties of Yukawa fluids in a wide range of coupling, up to the fluid-solid phase transition, are presented. These expressions demonstrate excellent agreement with the available results from numerical simulations. The approach provides simple and accurate tools to estimate thermodynamic properties of Yukawa fluids and related systems in a broad range of parameters.
Deviation of yukawa coupling and Higgs decay in gauge-Higgs Unification
Yuki Adachi; Nobuhito Maru
2015-07-28
We study the deviation of yukawa coupling in the gauge-Higgs unification scenario from the Standard Model one. Applying the obtained results to the tau and bottom yukawa couplings, we numerically calculate the signal strength of $gg \\to H \\to \\bar b b, \\bar {\\tau} \\tau$in the gauge-Higgs unification.
Deviation of yukawa coupling and Higgs decay in gauge-Higgs Unification
Adachi, Yuki
2015-01-01
We study the deviation of yukawa coupling in the gauge-Higgs unification scenario from the Standard Model one. Applying the obtained results to the tau and bottom yukawa couplings, we numerically calculate the signal strength of $gg \\to H \\to \\bar b b, \\bar {\\tau} \\tau$in the gauge-Higgs unification.
Practical expressions for the internal energy and pressure of Yukawa fluids
Sergey Khrapak; Hubertus Thomas
2015-02-13
Simple practical expressions are put forward, which allow to estimate thermodynamic properties of Yukawa fluids in a wide range of coupling, up to the fluid-solid phase transition. These expressions demonstrate excellent agreement with the available results from numerical simulations. The approach provides simple and accurate tool to estimate thermodynamic properties of Yukawa fluids and related systems in a broad range of parameters.
alpha-particle nuclear surface absorption below the Coulomb barrier in heavy nuclei
Avrigeanu, M.; Avrigeanu, V.
2010-07-15
An analysis of all available alpha-particle-induced reaction cross sections on nuclei within the mass number range 121<=A<=197, below the Coulomb barrier, is carried out. This analysis leads to an optical potential that describes the alpha-particle elastic scattering at low energies as well and both elastic-scattering and reaction data for 45<=A<=124. The energy dependence of the surface imaginary potential depth is proved to be essential for understanding alpha-particle interaction behavior below the Coulomb barrier.
Exact solution to the Coulomb wave using the linearized phase-amplitude method
NASA Astrophysics Data System (ADS)
Kiyokawa, Shuji
2015-08-01
The author shows that the amplitude equation from the phase-amplitude method of calculating continuum wave functions can be linearized into a 3rd-order differential equation. Using this linearized equation, in the case of the Coulomb potential, the author also shows that the amplitude function has an analytically exact solution represented by means of an irregular confluent hypergeometric function. Furthermore, it is shown that the exact solution for the Coulomb potential reproduces the wave function for free space expressed by the spherical Bessel function. The amplitude equation for the large component of the Dirac spinor is also shown to be the linearized 3rd-order differential equation.
Fermion Wavefunctions in Magnetized branes: Theta identities and Yukawa couplings
Ignatios Antoniadis; Alok Kumar; Binata Panda
2009-08-10
Computation of Yukawa couplings, determining superpotentials as well as the K\\"{a}hler metric, with oblique (non-commuting) fluxes in magnetized brane constructions is an interesting unresolved issue, in view of the importance of such fluxes for obtaining phenomenologically viable models. In order to perform this task, fermion (scalar) wavefunctions on toroidally compactified spaces are presented for general fluxes, parameterized by Hermitian matrices with eigenvalues of arbitrary signatures. We also give explicit mappings among fermion wavefunctions, of different internal chiralities on the tori, which interchange the role of the flux components with the complex structure of the torus. By evaluating the overlap integral of the wavefunctions, we give the expressions for Yukawa couplings among chiral multiplets arising from an arbitrary set of branes (or their orientifold images). The method is based on constructing certain mathematical identities for general Riemann theta functions with matrix valued modular parameter. We briefly discuss an application of the result, for the mass generation of non-chiral fermions, in the SU(5) GUT model presented by us in arXiv:0709.2799.
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.
Elementary excitations of a Higgs-Yukawa system
E. R. Takano Natti; A. F. R. de Toledo Piza; P. L. Natti; Chi-Yong Lin
2013-04-02
This work investigates the physics of elementary excitations for the so-called relativistic quantum scalar plasma system, also known as the Higgs-Yukawa system. Following the Nemes-Piza-Kerman-Lin many-body procedure, the Random-Phase Approximation (RPA) equations were obtained for this model by linearizing the Time-Dependent Hartree-Fock-Bogoliubov equations of motion around equilibrium. The resulting equations have a closed solution, from which the spectrum of excitation modes are studied. We show that the RPA oscillatory modes give the one-boson and two-fermion states of the theory. The results indicate the existence of bound states in certain regions in the phase diagram. Applying these results to recent LHC observations concerning the mass of the Higgs boson, we determine limits for the intensity of the coupling constant g of the Higgs-Yukawa model, in the RPA mean-field approximation, for three decay channels of the Higgs boson. Finally, we verify that, within our approximations, only Higgs bosons with masses larger than 190 GeV/c^2 can decay into top quarks.
Nonstandard Yukawa Couplings and Higgs Portal Dark Matter
Bishara, Fady; Uttayarat, Patipan; Zupan, Jure
2015-01-01
We study the implications of non-standard Higgs Yukawa couplings to light quarks on Higgs-portal dark matter phenomenology. Saturating the present experimental bounds on up-quark, down-quark, or strange-quark Yukawa couplings, the predicted direct dark matter detection scattering rate can increase by up to four orders of magnitude. The effect on the dark matter annihilation cross section, on the other hand, is subleading unless the dark matter is very light -- a scenario that is already excluded by measurements of the Higgs invisible decay width. We investigate the expected size of corrections in multi-Higgs-doublet models with natural flavor conservation, the type-II two-Higgs-doublet model, the Giudice-Lebedev model of light quark masses, minimal flavor violation new physics models, Randall-Sundrum, and composite Higgs models. We find that an enhancement in the dark matter scattering rate of an order of magnitude is possible. Finally, we point out that a discovery of Higgs-portal dark matter could lead to i...
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. .
NASA Astrophysics Data System (ADS)
Fadanelli, Raul C.; Dias, Johnny F.; Behar, Moni
2014-01-01
In this work we report on the results for the Coulomb heating of H+2, B+2 and C+2 diclusters traveling in Si < 110 ? direction covering an energy range from 200 keV/ion to 2400 keV/ion. Those results were obtained by combining the Rutherford backscattering spectrometry (RBS) and the particle induced X-ray emission (PIXE) techniques. By comparing the present results to those obtained previously for ions traveling in the narrower Si ? 100 ? channel, several common features are observed for the Coulomb heating values; especially, they follow a linear relationship as a function of the stored potential per ion. However, at variance with previous results, it is shown that the use of a Dirac-Hartree-Fock-Slater (DHFS) potential based on the ion mean charge states in amorphous targets leads to a considerable disagreement between the Coulomb heating values and the expected potential energies stored in the dicluster prior to the Coulomb explosion. In order to investigate this problem, a numerical procedure was developed in order to calculate the mean charge state values for ions traveling under channeling conditions. The use of the resulting charge states led to a linear relationship between the Coulomb heating values and the stored potential energy per ion of the diclusters. Moreover, the Coulomb heating/stored potential energy ratio amounts to about 2/3, which is in full agreement with those results obtained for the Si ? 100 ? direction.
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.
Enhancement of the Coulomb collision rate by individual particle wakes
NASA Astrophysics Data System (ADS)
Baalrud, Scott; Scheiner, Brett
2013-09-01
Charged particles moving in a plasma leave a trailing wake in their electric potential profile associated with the response function of the medium. For superthermal particles, these wakes can cause significant departures from the oft-assumed screened Coulomb potential profile. The wakes extend the interaction length scale beyond the Debye screening length for collisions between fast test particles and field particles in their wake. This can increase the Coulomb collision rate for velocities beyond the thermal speed. To demonstrate this effect, we consider the relaxation rate due to electron-electron collisions of an electron distribution function with initially depleted tails, as is common near boundary sheaths or double layers. This problem is related to Langmuir's paradox. We compare the standard Landau (Fokker-Planck) collision operator, which does not account for wakes, with the Lenard-Balescu collision operator, which includes wake effects through the linear dielectric response function. For this distribution, the linear dielectric is described by the incomplete plasma dispersion function. We compare the collision operators directly as well as the relaxation rate determined from a hybrid kinetic-fluid model. Charged particles moving in a plasma leave a trailing wake in their electric potential profile associated with the response function of the medium. For superthermal particles, these wakes can cause significant departures from the oft-assumed screened Coulomb potential profile. The wakes extend the interaction length scale beyond the Debye screening length for collisions between fast test particles and field particles in their wake. This can increase the Coulomb collision rate for velocities beyond the thermal speed. To demonstrate this effect, we consider the relaxation rate due to electron-electron collisions of an electron distribution function with initially depleted tails, as is common near boundary sheaths or double layers. This problem is related to Langmuir's paradox. We compare the standard Landau (Fokker-Planck) collision operator, which does not account for wakes, with the Lenard-Balescu collision operator, which includes wake effects through the linear dielectric response function. For this distribution, the linear dielectric is described by the incomplete plasma dispersion function. We compare the collision operators directly as well as the relaxation rate determined from a hybrid kinetic-fluid model. S. D. Baalrud, Phys. Plasmas 20, 012118 (2013).
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.
Roma "La Sapienza", UniversitÃ di
Critical indices for the Yukawa 2 quantum field theory F.Bonetto Dipartimento di Matematica'' di Roma Abstract The understanding of the Yukawa2 quantum field theory is still incomplete of the more investigated is the Yukawa 2 model describing the interaction between a massive boson, described
NASA Astrophysics Data System (ADS)
Wilcox, Bethany R.; Caballero, Marcos D.; Pepper, Rachel E.; Pollock, Steven J.
2013-01-01
Utilizing the integral expression of Coulomb's Law to determine the electric potential from a continuous charge distribution is a canonical exercise in Electricity and Magnetism (E&M). In this study, we use both think-aloud interviews and responses to traditional exam questions to investigate student difficulties with this topic at the upper-division level. Leveraging a theoretical framework for the use of mathematics in physics, we discuss how students activate, construct, execute and reflect on the integral form of Coulomb's Law when solving problems with continuous charge distributions. We present evidence that junior-level E&M students have difficulty mapping physical systems onto the mathematical expression for the Coulomb potential. Common challenges include difficulty expressing the difference vector in appropriate coordinates as well as determining expressions for the differential charge element and limits of integration for a specific charge distribution. We discuss possible implications of these findings for future research directions and instructional strategies.
Polynomial Solution of Non-Central Potentials
Sameer M. Ikhdair; Ramazan Sever
2007-02-19
We show that the exact energy eigenvalues and eigenfunctions of the Schrodinger equation for charged particles moving in certain class of non-central potentials can be easily calculated analytically in a simple and elegant manner by using Nikiforov and Uvarov (NU) method. We discuss the generalized Coulomb and harmonic oscillator systems. We study the Hartmann Coulomb and the ring-shaped and compound Coulomb plus Aharanov-Bohm potentials as special cases. The results are in exact agreement with other methods.
B. Kónya; G. Lévai; Z. Papp
1999-10-27
If a quantum mechanical Hamiltonian has an infinite symmetric tridiagonal (Jacobi) matrix form in some discrete Hilbert-space basis representation, then its Green's operator can be constructed in terms of a continued fraction. As an illustrative example we discuss the Coulomb Green's operator in Coulomb-Sturmian basis representation. Based on this representation, a quantum mechanical approximation method for solving Lippmann-Schwinger integral equations can be established, which is equally applicable for bound-, resonant- and scattering-state problems with free and Coulombic asymptotics as well. The performance of this technique is illustrated with a detailed investigation of a nuclear potential describing the interaction of two $\\alpha$ particles.
A family of attenuated Coulomb operators
NASA Astrophysics Data System (ADS)
Gill, Peter M. W.; Adamson, Ross D.
1996-10-01
We discuss a family of computationally useful approximations to the Coulomb operator. These operators, which we term CAP( m), are systematic improvements to our earlier CASE operator. In particular, we have CAP(0) ? CASE and CAP(?) ? 1/r. Because the CAP( m) approximations are all short-ranged, the computational cost of using one to compute the Coulomb energy of N localized charge distributions scales linearly with N. To investigate their accuracy, we have applied a number of CAP( m) approximations to the computation of the hydrogen atom energy and the NaCl Madelung constant. We find that the higher approximations model the original Coulomb operator quite well and the half-integer approximations, though non-vanishing at infinity, are especially accurate.
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.
Coulomb force as an entropic force
Wang Tower
2010-05-15
Motivated by Verlinde's theory of entropic gravity, we give a tentative explanation to the 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.
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.
Coulomb balls in Experiment and Simulation
Block, D.; Arp, O.; Piel, A.; Melzer, A.
2005-10-31
Recently, it was shown that it is possible to confine spherical dust clouds in a plasma. It was found that these dust clouds have a crystalline structure which differs notably from the well known fcc, bcc and hcp order in extended crystalline systems. The experiments show that the particles arrange in nested shells with hexagonal order on individual shells. The high transparency and the rather slow time scales of Coulomb balls allow to observe individual particles with video microscopy techniques and therefore to determine the structural properties of Coulomb balls with high accuracy. This contribution presents a comparison of experimental results and MD-Simulations.
Infrared divergence of the color-Coulomb self-energy in Coulomb gauge QCD
Y. Nakagawa; T. Saito; H. Toki; A. Nakamura
2006-10-31
We investigate the spectrum of the Faddeev-Popov operator in Coulomb gauge QCD using quenched SU(3) lattice simulation. In the confinement phase, we observe the accumulation of the near-zero modes of the FP operator at large lattice volumes, and the color-Coulomb self-energy diverges in the infrared limit. Moreover, even in the deconfinement phase, the behavior of the FP eigenvalue density is qualitatively the same as in the confinement phase and the color-Coulomb self-energy is infrared divergent.
NASA Astrophysics Data System (ADS)
Przybytek, Michal; Helgaker, Trygve
2013-08-01
We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (?H = 2) and eight (?1st = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (? _min^G=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d4 with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step—namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems; however, this scaling can be reduced to linear by introducing more effective techniques for recognizing significant three-center overlap distributions.
Przybytek, Michal; Helgaker, Trygve
2013-08-01
We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (?(H) = 2) and eight (?(1st) = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (?min (G)=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d(4) with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step-namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems; however, this scaling can be reduced to linear by introducing more effective techniques for recognizing significant three-center overlap distributions. PMID:23927250
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.
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.
Phase structure of a three-dimensional Yukawa model
Hidenori Sonoda
2011-05-09
We use the method of the exact renormalization group to study the renormalization group flows of an O(N) invariant Yukawa model in three dimensional Euclidean space consisting of one real scalar and N real spinor fields. We obtain a phase structure similar to that of the N-vector model with cubic anisotropy, possessing a region of parameters exhibiting a first order transition. The particular case with one real fermion (N=1) belongs to the same universality class as the Wess-Zumino model with one supersymmetry. For the critical exponents of the Wilson-Fisher type fixed points, our 1-loop approximations are generally consistent with the results of previous studies.
Ultraviolet Properties of the Spinless, One-Particle Yukawa Model
D. -A. Deckert; A. Pizzo
2012-09-30
We consider the one-particle sector of the spinless Yukawa model, which describes the interaction of a nucleon with a real field of scalar massive bosons (neutral mesons). The nucleon as well as the mesons have relativistic dispersion relations. In this model we study the dependence of the nucleon mass shell on the ultraviolet cut-off $\\Lambda$. For any finite ultraviolet cut-off the nucleon one-particle states are constructed in a bounded region of the energy-momentum space. We identify the dependence of the ground state energy on $\\Lambda$ and the coupling constant. More importantly, we show that the model considered here becomes essentially trivial in the limit $\\Lambda\\to\\infty$ regardless of any (nucleon) mass and self-energy renormalization. Our results hold in the small coupling regime.
The twisted open string partition function and Yukawa couplings
Rodolfo Russo; Stefano Sciuto
2007-09-12
We use the operator formalism to derive the bosonic contribution to the twisted open string partition function in toroidal compactifications. This amplitude describes, for instance, the planar interaction between g+1 magnetized or intersecting D-branes. We write the result both in the closed and in the open string channel in terms of Prym differentials on the appropriate Riemann surface. Then we focus on the g=2 case for a 2-torus. By factorizing the twisted partition function in the open string channel we obtain an explicit expression for the 3-twist field correlator, which is the main ingredient in the computation of Yukawa couplings in D-brane phenomenological models. This provides an alternative method for computing these couplings that does not rely on the stress-energy tensor technique.
Collective excitations of a spherically confined Yukawa plasma
Kaehlert, H.; Bonitz, M.
2011-05-15
The complete spectrum of eigenmodes of a spherically confined Yukawa plasma is presented, based on first-principle molecular dynamics simulations. These results are compared with a recent fluid theory for the multipole modes of this system [H. Kaehlert and M. Bonitz, Phys. Rev. E 82, 036407 (2010)] and with the exact N-particle eigenmodes in the crystalline phase. Simulations confirm the existence of high-order modes found in cold fluid theory. We investigate the influence of screening, coupling, and friction on the mode spectra in detail. Good agreement between theory and simulation is found for weak to moderate screening and low-order modes. In addition, a number of new modes are observed which are missing in the fluid theory. The relations between the breathing mode in the fluid theory, simulation, and the crystal eigenmode are investigated in further detail.
Constraining the Charm Yukawa and Higgs-quark Coupling Universality
Gilad Perez; Yotam Soreq; Emmanuel Stamou; Kohsaku Tobioka
2015-09-07
We introduce four different types of data-driven analyses with different level of robustness that constrain the size of the Higgs-charm Yukawa coupling: (i) recasting the vector-boson associated, Vh, analyses that search for bottom-pair final state. We use this mode to directly and model independently constrain the Higgs to charm coupling, y_c/y_c^{SM} J/\\psi\\gamma, y_c/y_c^{SM} < 220; (iv) a global fit to the Higgs signal strengths, y_c/y_c^{SM} < 6.2. A comparison with t\\bar{t}h data allows us to show that current data eliminates the possibility that the Higgs couples to quarks in a universal way, as is consistent with the Standard Model (SM) prediction. Finally, we demonstrate how the experimental collaborations can further improve our direct bound by roughly an order of magnitude by charm-tagging, as already used in new physics searches.
Early LHC phenomenology of Yukawa-bound heavy QQ mesons
Enkhbat, Tsedenbaljir; Hou, Wei-Shu; Yokoya, Hiroshi
2011-11-01
Current limits from the LHC on fourth generation quarks are already at the unitarity bound of 500 GeV or so. If they exist, the strong Yukawa couplings are turning nonperturbative, and may form bound states. We study the domain of m{sub b'} and m{sub t'} in the range of 500 to 700 GeV, where we expect binding energies are mainly of Yukawa origin, with QCD subdominant. To be consistent with electroweak precision tests, the t' and b' quarks have to be nearly degenerate, exhibiting a new 'isospin'. Comparing relativistic expansion with a relativistic bound state approach, we find the most interesting is the production of a color octet, isosinglet vector meson (a 'gluon-prime') via qq-bar{yields}{omega}{sub 8}. Leading decay modes are {pi}{sub 8}{sup {+-}}W{sup {+-}}, {pi}{sub 8}{sup 0}Z{sup 0}, and constituent quark decay, with qq and tt-bar' and bb' subdominant. The color octet, isovector pseudoscalar {pi}{sub 8} meson decays via constituent quark decay, or to Wg. These decay rates are parameterized by the decay constant, the binding energy and mass differences, and V{sub tb'}. For small V{sub t'b}, one could have a spectacular signal of WWg, where a soft W accompanies a very massive Wg pair. In general, however, one has high multiplicity signals with b, W, and t jet substructures that are not so different from the t't-bar' and b'b-bar' search.
Accelerated expansion in modified gravity with a Yukawa-like term
K. Atazadeh; H. R. Sepangi
2006-10-01
We discuss the Palatini formulation of modified gravity including a Yukawa-like term. It is shown that in this formulation, the Yukawa term offers an explanation for the current exponential accelerated expansion of the universe and reduces to the standard Friedmann cosmology in the appropriate limit. We then discuss the scalar-tensor formulation of the model as a metric theory and show that the Yukawa term predicts a power-law acceleration at late-times. The Newtonian limit of the theory is also discussed in context of the Palatini formalism.
Investigation of the phase structure of a chirally-invariant Higgs-Yukawa model
John Bulava; Philipp Gerhold; George W. -S. Hou; Karl Jansen; Bastian Knippschild; C. -J. David Lin; Kei-Ichi Nagai; Attila Nagy; Kenji Ogawa
2012-10-31
We present new data on our ongoing project on the investigation of the phase structure of the Higgs-Yukawa model at large bare Yukawa couplings. The data presented last year are extended in terms of statistics, the number of bare Yukawa couplings at existing, and new larger volumes. In addition, this study is extended by a finite temperature project at the physical top quark mass m_t =175 GeV and a hypothetical fourth generation top quark with a mass of m_t' =700 GeV .
Tennessee, University of
attraction by acceptors F. Popescu,1, * C. en,1,2 E. Dagotto,3,4 and A. Moreo3,4 1Department of Physics magnetic semiconductors DMSs is studied systematically by taking into consideration the Coulomb attraction Carlo MC calculations. It is shown that the addition of a square-well-like attractive potential can
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.
Two-centre Dirac-Coulomb operators: Regularity and bonding properties
Two-centre Dirac-Coulomb operators: Regularity and bonding properties Ph. Briet * and H. Hogreve y properties of the Dirac operator for homonuclear two-centre one-electron sys- tems are studied. This includes, the continuity and di#11;erentiability of the electronic contribution to the potential energy curves are shown
Statistical theory of Coulomb blockade oscillations: Quantum chaos in quantum dots
Jalabert, R.A.; Stone, A.D.; Alhassid, Y. )
1992-06-08
We develop a statistical theory of the amplitude of Coulomb blockade oscillations in semiconductor quantum dots based on the hypothesis that chaotic dynamics in the dot potential leads to behavior described by random-matrix theory. Breaking time-reversal symmetry is predicted to cause an experimentally observable change in the distribution of amplitudes. The theory is tested numerically and good agreement is found.
CHALLENGES AND PROSPECTS OF COULOMB SPACECRAFT FORMATIONS
King, Lyon B.
Coulomb forces is a relatively new technology for spacecraft control, and may have application for a wide. Formation flying on the order of tens of meters is very difficult using conventional ion propulsion methods will attain a negative charge due to a higher electron mobility, as compared to the mobility of heavier ions
Coulomb's law particle flow for nonlinear filters
Fred Daum; Jim Huang; Arjang Noushin
2011-01-01
We have invented a new theory of exact particle flow for nonlinear filters. The flow of particles corresponding to Bayes' rule is computed from the gradient of the solution of Poisson's equation, and it is analogous to Coulomb's law. Our theory is a radical departure from other particle filters in several ways: (1) we compute Bayes' rule using a flow
Boltzmann-Langevin theory of Coulomb drag
NASA Astrophysics Data System (ADS)
Chen, W.; Andreev, A. V.; Levchenko, A.
2015-06-01
We develop a Boltzmann-Langevin description of the Coulomb drag effect in clean double-layer systems with large interlayer separation d as compared to the average interelectron distance ?F. Coulomb drag arises from density fluctuations with spatial scales of order d . At low temperatures, their characteristic frequencies exceed the intralayer equilibration rate of the electron liquid, and Coulomb drag may be treated in the collisionless approximation. As temperature is raised, the electron mean free path becomes short due to electron-electron scattering. This leads to local equilibration of electron liquid, and consequently drag is determined by hydrodynamic density modes. Our theory applies to both the collisionless and the hydrodynamic regimes, and it enables us to describe the crossover between them. We find that drag resistivity exhibits a nonmonotonic temperature dependence with multiple crossovers at distinct energy scales. At the lowest temperatures, Coulomb drag is dominated by the particle-hole continuum, whereas at higher temperatures of the collision-dominated regime it is governed by the plasmon modes. We observe that fast intralayer equilibration mediated by electron-electron collisions ultimately renders a stronger drag effect.
Coulomb's Electrical Measurements. Experiment No. 14.
ERIC Educational Resources Information Center
Devons, Samuel
Presented is information related to the life and work of Charles Coulomb as well as detailed notes of his measurements of the distribution of electricity on conductors. The two methods that he used (the large torsion balance, and the timing of "force" oscillations) are described. (SA)
An alternative simple solution of the sextic anharmonic oscillator and perturbed Coulomb problems
Sameer M. Ikhdair
2007-02-26
Utilizing an appropriate ansatz to the wave function, we reproduce the exact bound-state solutions of the radial Schrodinger equation to various exactly solvable sextic anharmonic oscillator and confining perturbed Coulomb models in $D$-dimensions. We show that the perturbed Coulomb problem with eigenvalue $E$ can be transformed to a sextic anharmonic oscillator problem with eigenvalue E. We also check the explicit relevance of these two related problems in higher-space dimensions. It is shown that exact solutions of these potentials exist when their coupling parameters with $k=D+2\\ell $ appearing in the wave equation satisfy certain constraints.
Exact Path-Integral Solution of the Dirac-Coulomb Problem
NASA Astrophysics Data System (ADS)
Kayed, M. A.; Inomata, A.
1984-07-01
An exact path-integral solution of the Dirac equation with a Coulomb potential is found. The energy-dependent Green's function of the second-order Dirac-Coulomb equation, expressed as a polar-coordinate path integral, is reduced to the exactly solvable path integral for an isotropic harmonic oscillator by a coordinate transformation combined with a local time rescaling. The Green's function of the linear Dirac equation is evaluated with the help of the Biedenharn transformation. The energy spectrum for the bound states is also obtained.
Laser-dressed vacuum polarization in a Coulomb field
Milstein, A. I.; Terekhov, I. S.; Jentschura, U. D.; Keitel, C. H.
2005-11-15
We investigate quantum electrodynamic effects under the influence of an external, time-dependent electromagnetic field, which mediates dynamic modifications of the radiative corrections. Specifically, we consider the quantum electrodynamic vacuum-polarization tensor under the influence of two external background fields: a strong laser field and a nuclear Coulomb field. We calculate the charge and current densities induced by a nuclear Coulomb field in the presence of a laser field. We find the corresponding induced scalar and vector potentials. The induced potential, in first-order perturbation theory, leads to a correction to atomic energy levels. The external laser field breaks the rotational symmetry of the system. Consequently, the induced charge density is not spherically symmetric, and the energy correction therefore leads to a ''polarized Lamb shift.'' In particular, the laser generates an additional potential with a quadrupole moment. The corresponding laser-dressed vacuum-polarization potential behaves like 1/r{sup 3} at large distances, unlike the Uehling potential, which vanishes exponentially for large r. The energy corrections are of the same order of magnitude for hydrogenic levels, irrespective of the angular momentum quantum number. The induced current leads to a transition dipole moment which oscillates at the second harmonic of the laser frequency and is mediated by second-order harmonic generation in the vacuum-polarization loop. In the far field, at distances r>>1/{omega} from the nucleus ({omega} is the laser frequency), the laser induces mutually perpendicular electric and magnetic fields, which give rise to an energy flux that corresponds to photon fusion leading to the generation of real photons, again at the second harmonic of the laser. Our investigation might be useful for other situations where quantum field theoretic phenomena are subjected to external fields of a rather involved structure.
Crystallization in Two-Component Coulomb Systems M. Bonitz,1
Bonitz, Michael
Crystallization 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 parameters for the existence of Coulomb crystals are derived for both classical and quantum crystals
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.
NASA Astrophysics Data System (ADS)
Casterman, D.; De Souza, M. M.
2010-03-01
An efficient numerical method for the evaluation of the Green's function used in the calculation of the Coulomb-limited electron mobility in high-? metal oxide semiconductor field effect transistors is presented. This simple method is applicable to gate stacks with an arbitrary number of layers of varying dielectric permittivity. A charge profile with varying dielectric profile is demonstrated to show an increase in Coulomb-limited mobility of 16% in comparison to a point charge located at the interface. A metal gate reduces the scattering potential due to its infinite dielectric constant which leads to lesser impact of charge in comparison to a polysilicon gate. The Coulomb-limited mobility for devices having identical equivalent oxide thickness of 0.5-0.8 nm with (a) a hafnium silicate interfacial layer (IL) and (b) zero IL is presented.
Pair correlation functions and phase separation in a two component point Yukawa fluid
P. Hopkins; A. J. Archer; R. Evans
2005-12-16
We investigate the structure of a binary mixture of particles interacting via purely repulsive (point) Yukawa pair potentials with a common inverse screening length $\\lambda$. Using the hyper-netted chain closure to the Ornstein-Zernike equations, we find that for a system with `ideal' (Berthelot mixing rule) pair potential parameters for the interaction between unlike species, the asymptotic decay of the total correlation functions crosses over from monotonic to damped oscillatory on increasing the fluid total density at fixed composition. This gives rise to a Kirkwood line in the phase diagram. We also consider a `non-ideal' system, in which the Berthelot mixing rule is multiplied by a factor $(1+\\delta)$. For any $\\delta>0$ the system exhibits fluid-fluid phase separation and remarkably the ultimate decay of the correlation functions is now monotonic for all (mixture) state points. Only in the limit of vanishing concentration of either species does one find oscillatory decay extending to $r = \\infty$. In the non-ideal case the simple random phase approximation provides a good description of the phase separation and the accompanying Lifshitz line.
Coulomb impurity scattering in topological insulator thin films
NASA Astrophysics Data System (ADS)
Yin, Gen; Wickramaratne, Darshana; Zhao, Yuanyuan; Lake, Roger K.
2014-07-01
Inter-surface coupling in thin-film topological insulators can reduce the surface state mobility by an order of magnitude in low-temperature transport measurements. The reduction is caused by a reduction in the group velocity and an increased sz component of the surface-state spin which weakens the selection rule against large-angle scattering. An intersurface potential splits the degenerate bands into a Rashba-like bandstructure. This reduces the intersurface coupling, it largely restores the selection rule against large angle scattering, and the ring-shaped valence band further reduces backscattering by requiring, on average, larger momentum transfer for backscattering events. The effects of temperature, Fermi level, and intersurface potential on the Coulomb impurity scattering limited mobility are analyzed and discussed.
Confronting Four Zero Neutrino Yukawa Textures with $N_2^{}$-dominated Leptogenesis
Jue Zhang
2015-04-10
We consider a restricted Type-I seesaw scenario with four texture zeros in the neutrino Yukawa matrix, in the weak basis where both the charged-lepton Yukawa matrix and the Majorana mass matrix for right-handed neutrinos are diagonal and real. Inspired by grand unified theories, we further require the neutrino Yukawa matrix to exhibit a similar hierarchical pattern to that in the up-type quark Yukawa matrix. With such a hierarchy requirement, we find that leptogenesis, which would operate in a $N_2^{}$-dominated scenario with the asymmetry generated by the next-to-lightest right-handed neutrino $N_2^{}$, can greatly reduce the number of allowed textures, and disfavors the scenario that three light neutrinos are quasi-degenerate. Such a quasi-degenerate scenario of light neutrinos may soon be tested in upcoming neutrino experiments.
Confronting Four Zero Neutrino Yukawa Textures with $N_2^{}$-dominated Leptogenesis
Jue Zhang
2015-09-17
We consider a restricted Type-I seesaw scenario with four texture zeros in the neutrino Yukawa matrix, in the weak basis where both the charged-lepton Yukawa matrix and the Majorana mass matrix for right-handed neutrinos are diagonal and real. Inspired by grand unified theories, we further require the neutrino Yukawa matrix to exhibit a similar hierarchical pattern to that in the up-type quark Yukawa matrix. With such a hierarchy requirement, we find that leptogenesis, which would operate in a $N_2^{}$-dominated scenario with the asymmetry generated by the next-to-lightest right-handed neutrino $N_2^{}$, can greatly reduce the number of allowed textures, and disfavors the scenario that three light neutrinos are quasi-degenerate. Such a quasi-degenerate scenario of light neutrinos may soon be tested in upcoming neutrino experiments.
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.
Constraining General Two Higgs Doublet Models by the Evolution of Yukawa Couplings
Johan Bijnens; Jie Lu; Johan Rathsman
2012-05-04
We study how general two Higgs doublet models can be constrained by considering their properties under renormalization group evolution of the Yukawa couplings. We take into account both the appearance of a Landau pole as well as off-diagonal Yukawa couplings leading to flavour changing neutral currents in violation with experimental constraints at the electroweak scale. We find that the latter condition can be used to limit the amount of Z2 symmetry breaking allowed in a given model.
Practical expressions for the internal energy and pressure of Yukawa fluids.
Khrapak, Sergey A; Thomas, Hubertus M
2015-02-01
Simple practical expressions that allow estimation of thermodynamic properties of Yukawa fluids in a wide range of coupling, up to the fluid-solid phase transition, are presented. These expressions demonstrate excellent agreement with the available results from numerical simulations. The approach provides simple and accurate tools to estimate thermodynamic properties of Yukawa fluids and related systems in a broad range of parameters. PMID:25768619
3D dust clouds (Yukawa Balls) in strongly coupled dusty plasmas
Melzer, A.; Passvogel, M.; Miksch, T.; Ikkurthi, V. R.; Schneider, R.; Block, D.; Piel, A.
2010-06-16
Three-dimensional finite systems of charged dust particles confined to concentric spherical shells in a dusty plasma, so-called 'Yukawa balls', have been studied with respect to their static and dynamic properties. Here, we review the charging of particles in a dusty plasma discharge by computer simulations and the respective particle arrangements. The normal mode spectrum of Yukawa balls is measured from the 3D thermal Brownian motion of the dust particles around their equilibrium positions.
Instanton induced Yukawa couplings from distant E3 and E(-1) instantons
Mark D. Goodsell; Lukas T. Witkowski
2015-09-02
We calculate non-perturbative contributions to Yukawa couplings on D3-branes at orbifold singularities due to E3 and fractional E(-1) instantons which do not intersect the visible sector branes. While distant E3 instantons on bulk cycles typically contribute to Yukawa couplings, we find that distant fractional E(-1) can also give rise to new Yukawa couplings. However, fractional E(-1) instantons only induce Yukawa couplings if they are located at a singularity which shares a collapsed homologous two-cycle with the singularity supporting the visible sector. The non-perturbative contributions to Yukawa couplings exhibit a different flavour structure than the tree-level Yukawa couplings and, as a result, they can be sources of flavour violation. This is particularly relevant for schemes of moduli stabilisation which rely on superpotential contributions from E3 instantons, such as KKLT or the Large Volume Scenario. As a byproduct of our analysis, we shed some new light on the properties of annulus diagrams with matter field insertions in stringy instanton calculus.
Instanton induced Yukawa couplings from distant E3 and E(-1) instantons
Goodsell, Mark D
2015-01-01
We calculate non-perturbative contributions to Yukawa couplings on D3-branes at orbifold singularities due to E3 and fractional E(-1) instantons which do not intersect the visible sector branes. While distant E3 instantons on bulk cycles typically contribute to Yukawa couplings, we find that distant fractional E(-1) can also give rise to new Yukawa couplings. However, fractional E(-1) instantons only induce Yukawa couplings if they are located at a singularity which shares a collapsed homologous two-cycle with the singularity supporting the visible sector. The non-perturbative contributions to Yukawa couplings exhibit a different flavour structure than the tree-level Yukawa couplings and, as a result, they can be sources of flavour violation. This is particularly relevant for schemes of moduli stabilisation which rely on superpotential contributions from E3 instantons, such as KKLT or the Large Volume Scenario. As a byproduct of our analysis, we shed some new light on the properties of annulus diagrams with m...
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.
Feynman rules for Coulomb gauge QCD
Andrasi, A.; Taylor, J.C.
2012-10-15
The Coulomb gauge in nonabelian gauge theories is attractive in principle, but beset with technical difficulties in perturbation theory. In addition to ordinary Feynman integrals, there are, at 2-loop order, Christ-Lee (CL) terms, derived either by correctly ordering the operators in the Hamiltonian, or by resolving ambiguous Feynman integrals. Renormalization theory depends on the sub-graph structure of ordinary Feynman graphs. The CL terms do not have a sub-graph structure. We show how to carry out renormalization in the presence of CL terms, by re-expressing these as 'pseudo-Feynman' integrals. We also explain how energy divergences cancel. - Highlights: Black-Right-Pointing-Pointer In Coulomb gauge QCD, we re-express Christ-Lee terms in the Hamiltonian as pseudo-Feynman integrals. Black-Right-Pointing-Pointer This gives a subgraph structure, and allows the ordinary renormalization process. Black-Right-Pointing-Pointer It also leads to cancellation of energy-divergences.
Bionic Coulomb phase on the pyrochlore lattice
NASA Astrophysics Data System (ADS)
Khemani, V.; Moessner, R.; Parameswaran, S. A.; Sondhi, S. L.
2012-08-01
A class of three-dimensional classical lattice systems with macroscopic ground state degeneracies, most famously the spin ice system, are known to exhibit “Coulomb” phases wherein long wavelength correlations within the ground state manifold are described by an emergent Maxwell electrodynamics. We discuss a more elaborate example of this phenomenon—the four-state Potts model on the pyrochlore lattice—where the long wavelength description now involves three independent gauge fields, as we confirm via simulation. The excitations above the ground state manifold are bions, defects that are simultaneously charged under two of the three gauge fields, and they exhibit an entropic interaction dictated by these charges. We also show that the distribution of flux loops exhibits a scaling with loop length and system size previously identified as characteristic of Coulomb phases.
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.
Nonlinear screening theory of the Coulomb glass.
Pankov, Sergey; Dobrosavljevi?, Vladimir
2005-02-01
A nonlinear screening theory is formulated to study the problem of gap formation and its relation to glassy freezing in classical Coulomb glasses. We find that a pseudogap ("plasma dip") in a single-particle density of states begins to open already at temperatures comparable to the Coulomb energy. This phenomenon is shown to reflect the emergence of short-range correlations in a liquid (plasma) phase, a process which occurs even in the absence of disorder. Glassy ordering emerges when disorder is present, but this occurs only at temperatures roughly an order of magnitude lower. Our result demonstrate that the formation of the plasma dip at high temperatures is a process distinct from the formation of the Efros-Shklovskii pseudogap, which in our model emerges only within the glassy phase. PMID:15783578
Non-commutative relativistic equation with a Coulomb potential
Zaim, Slimane; Khodja, Lamine; Delenda, Yazid [Departement de Physique, Faculte des Sciences, Universite Hadj Lakhdar - Batna (Algeria); Departement de Physique, Faculte des Sciences Exactes, Universite de Bejaia (Algeria); Departement de Physique, Faculte des Sciences, Universite Hadj Lakhdar - Batna (Algeria)
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.
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 dissociation of {sup 27} P
Beceiro, S.; Cortina-Gil, D.; Suemmerer, K.
2010-04-26
The {sup 26}Al nucleus has a shorter life-time than the Universe showing that the nucleosynthesis of this element might be an ongoing process in stars. The reaction {sup 26}Si(p,gamma){sup 27} P competes with the production of {sup 26}Al. Coulomb dissociation of {sup 27} P is an indirect method to measure that reaction. An experiment was performed at GSI with a {sup 36}Ar primary beam at 500 MeV to measure this reaction.
Generalized Coulomb pairing in the condensed state
K. Moulopoulos; N. W. Ashcroft
1991-01-01
Starting with a view of condensed matter as a neutral assembly of electrons and nuclei, with mutual Coulomb interactions, a coherent-state functional-integral approach gives a first-principles theory of pairing phases that requires no adiabatic separation of time scales. For electrons and protons, both fermions, we show that an interdependent pairing of electrons and of protons can arise at low temperature
Coulomb collision effects on linear Landau damping
Callen, J. D., E-mail: callen@engr.wisc.edu [University of Wisconsin, Madison, Wisconsin 53706-1609 (United States)
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.
Fermionic dark matter with pseudo-scalar Yukawa interaction
Ghorbani, Karim, E-mail: k-ghorbani@araku.ac.ir [Physics Department, Faculty of Sciences, Arak University, Arak, 38156-8-8349 (Iran, Islamic Republic of)
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.
Sliding along Coulombic shear faults in ice
NASA Astrophysics Data System (ADS)
Fortt, A.; Schulson, E. M.; Russell, E.
2003-01-01
New experiments have been performed on the resistance to inelastic deformation through frictional sliding along naturally-formed Coulombic shear faults in ice Ih. Coulombic faults mark terminal failure of virgin material when loaded rapidly under a moderate degree of confinement. The experiments were performed on S2 fresh-water ice at -10degreesC, proportionally loaded biaxially across the columns along a variety of all-compressive paths. Two kinds of behavior were observed. At higher sliding velocities (8 x 10(-2) and 8 x 10(-1) mm s(-1)) sliding was noisy and the process exhibited velocity weakening. At a lower sliding velocity (8 x 10(-4) mm s(-1)) sliding was quiet and fault healing occurred. The two kinds of sliding are indicative of brittle-like (at higher speeds) and ductile-like (at lower speeds) behavior, and are explained in terms of fracture and creep. Within the brittle regime, a power law describes the relationship between the shear strength of the fault and the normal stress across it at the onset of sliding, while Coulomb's law describes the relationship once sliding has progressed by about 2 mm.
Itinerant electrons in the Coulomb phase
NASA Astrophysics Data System (ADS)
Jaubert, L. D. C.; Piatecki, Swann; Haque, Masudul; Moessner, R.
2012-02-01
We study the interplay between magnetic frustration and itinerant electrons. For example, how does the coupling to mobile charges modify the properties of a spin liquid, and does the underlying frustration favor insulating or conducting states? Supported by Monte Carlo simulations, our goal is in particular to provide an analytical picture of the mechanisms involved. The models under consideration exhibit Coulomb phases in two and three dimensions, where the itinerant electrons are coupled to the localized spins via double exchange interactions. Because of the Hund coupling, magnetic loops naturally emerge from the Coulomb phase and serve as conducting channels for the mobile electrons, leading to doping-dependent rearrangements of the loop ensemble in order to minimize the electronic kinetic energy. At low electron density ?, the double exchange coupling mainly tends to segment the very long loops winding around the system into smaller ones while it gradually lifts the extensive degeneracy of the Coulomb phase with increasing ?. For higher doping, the results are strongly lattice dependent, displaying loop crystals with a given loop length for some specific values of ?. By varying ?, they can melt into different mixtures of these loop crystals, recovering extensive degeneracy in the process. Finally, we contrast this to the qualitatively different behavior of analogous models on kagome or triangular lattices.
Transport properties for an electroneutral Yukawa-type fluid in the MSA
NASA Astrophysics Data System (ADS)
Montes-Perez, J.; Herrera, J. N.
2014-01-01
In the framework of a linear response theory, in which Onsager’s continuity equations are combined with the Mean Spherical Approximation (MSA) from the theory of correlation functions in equilibrium, and using a Green’s function formalism, we consider the transport properties of electrolytes. The interaction between the ions in the electrolyte is represented by an intermolecular Yukawa potential which satisfies the electroneutrality condition. The model contains an adjustable parameter z which takes into account the effects of the solvent. Transport processes in an ionic solution are determined by two dominant forces: the relaxation and the electrophoretic forces; their contributions to the transport properties are calculated using the Fuoss-Onsager theory. We find the conductivity and the self-diffusion coefficient for a family of electrolytes using the linear response theory. The predictions of our model can be adjusted by means of the parameter z. The electrophoretic effect, due to the hydrodynamic interaction between the ions, is calculated using the Rotne-Prager tensor. Our theoretical results are in good agreement with experimental data for electrolytes 1-1, even for high concentrations. We applied this theory also to two unsymmetrical electrolytes, namely the aqueous solutions of MgCl2 and CaCl2, with results in good accord with experimental data.
Critical fluctuations and anomalous transport in soft Yukawa-Langevin systems.
Ratynskaia, S; Regnoli, G; Rypdal, K; Klumov, B; Morfill, G
2009-10-01
Simulation of a Langevin-dynamics model demonstrates emergence of critical fluctuations and anomalous grain transport which have been observed in experiments on "soft" quasi-two-dimensional dusty plasma clusters. Our model does not contain external drive or plasma interactions that serve to drive the system away from thermodynamic equilibrium. The grains are confined by an external potential, interact via static Yukawa forces, and are subject to stochastic heating and dissipation from neutrals. One remarkable feature is emergence of leptokurtic probability distributions of grain displacements xi(tau) on time scales tau < tau(Delta), where tau(Delta) is the time at which the standard deviation sigma(tau) identical with (xi(2)(tau))(1/2) approaches the mean intergrain distance Delta. Others are development of humps in the distributions on multiples of Delta , anomalous Hurst exponents, and transitions from leptokurtic toward Gaussian displacement distributions on time scales tau > tau(Delta). The latter is a signature of intermittency, here interpreted as a transition from bursty transport associated with hopping on intermediate time scales to vortical flows on longer time scales. These intermittency features are quantitatively modeled by a single-particle Itô-Langevin stochastic equation with a nonlinear drift term. PMID:19905458
Critical fluctuations and anomalous transport in soft Yukawa-Langevin systems
NASA Astrophysics Data System (ADS)
Ratynskaia, S.; Regnoli, G.; Rypdal, K.; Klumov, B.; Morfill, G.
2009-10-01
Simulation of a Langevin-dynamics model demonstrates emergence of critical fluctuations and anomalous grain transport which have been observed in experiments on “soft” quasi-two-dimensional dusty plasma clusters. Our model does not contain external drive or plasma interactions that serve to drive the system away from thermodynamic equilibrium. The grains are confined by an external potential, interact via static Yukawa forces, and are subject to stochastic heating and dissipation from neutrals. One remarkable feature is emergence of leptokurtic probability distributions of grain displacements ?(?) on time scales ??? . The latter is a signature of intermittency, here interpreted as a transition from bursty transport associated with hopping on intermediate time scales to vortical flows on longer time scales. These intermittency features are quantitatively modeled by a single-particle Itô-Langevin stochastic equation with a nonlinear drift term.
The Higgs-Yukawa model with higher dimension operators via EMFT
Akerlund, Oscar
2015-01-01
Using Extended Mean Field Theory (EMFT) on the lattice, we study properties of the Higgs-Yukawa model as an approximation of the Standard Model Higgs sector, and the effect of higher dimension operators. We note that the discussion of vacuum stability is completely modified in the presence of a $\\phi^6$ term, and that the Higgs mass no longer appears fine tuned. We also study the finite temperature transition. Without higher dimension operators the transition is found to be second order (crossover with gauge fields) for the experimental value of the Higgs mass $M_h=125$ GeV. By taking a $\\phi^6$ interaction in the Higgs potential as a proxy for a UV completion of the Standard Model, the transition becomes stronger and turns first order if the scale of new physics, i.e. the mass of the lightest mediator particle, is around $1.5$ TeV. This implies that electroweak baryogenesis may be viable in models which introduce new particles around that scale.
Observation of the Rayleigh-Bénard convection cells in strongly coupled Yukawa liquids
NASA Astrophysics Data System (ADS)
Charan, Harish; Ganesh, Rajaraman
2015-08-01
Using "first principles" molecular dynamics simulation, we report for the first time the formation of Rayleigh-Bénard convection cells (RBCC) in two-dimensional strongly coupled Yukawa liquids, characterized by coupling strength ? (ratio of average potential energy to kinetic energy per particle) and screening parameter ? (ratio of average inter-particle distance to Debye length). For typical values of (?, ?), existence of a critical external temperature difference is demonstrated, beyond which RBCC are seen to set in. Beyond this critical external temperature difference, the strength of the maximum convective flow velocity is shown to exhibit a new, hitherto unsuspected linear relationship with external temperature difference and with a slope independent of (?, ?). The time taken for the transients to settle down (?s) to a steady state RBCC is found to be maximum close to the above said critical external temperature difference and is seen to reduce with increasing external temperature difference. For the range of values of (?, ?) considered here, ?s ? 10 000-20 000 ?pd-1 , where ?pd is dust plasma frequency. As ? is increased to very high values, due to strong coupling effects, cells are seen to be in a transient state without attaining a steady state for as long as 100 000 ?pd-1 , even for a very high external temperature difference. Role of system size, aspect ratio, and dust-neutral collisions has also been addressed.
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.
Coulomb quantum kinetics in a dense electron gas
NASA Astrophysics Data System (ADS)
Haug, Hartmut; Ell, Claudia
1992-07-01
The semiclassical Boltzmann equation for a dense electron gas is generalized to a quantum kinetic equation beyond the approximation of isolated collisions. The resulting quantum kinetic equation for the Wigner function contains memory effects, which are determined by the retarded and advanced non- equilibrium Green's functions of the scattered electrons and the screened Coulomb potential. A closed set of equations for the distribution and the spectral functions is given which is exact within the generalized Kadanoff-Baym ansatz and the random-phase approximation. Simplifying approximations are given which result in a quantum kinetic equation with memory kernels similar to those obtained for the electron-phonon scattering. In the limit of completed collisions, the quantum kinetic equation reduces to a Boltzmann equation in which the energy conservation is smeared out due to the finite time interval and due to collision broadening.
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.
Dynamic stresses, coulomb failure, and remote triggering: corrected
Hill, David P.
2012-01-01
Dynamic stresses associated with crustal surface waves with 15–30 s periods and peak amplitudes <1??MPa are capable of triggering seismicity at sites remote from the generating mainshock under appropriate conditions. Coulomb failure models based on a frictional strength threshold offer one explanation for instances of rapid?onset triggered seismicity that develop during the surface?wave peak dynamic stressing. Evaluation of the triggering potential of surface?wave dynamic stresses acting on critically stressed faults using a Mohr’s circle representation together with the Coulomb failure criteria indicates that Love waves should have a higher triggering potential than Rayleigh waves for most fault orientations and wave incidence angles. That (1) the onset of triggered seismicity often appears to begin during the Rayleigh wave rather than the earlier arriving Love wave, and (2) Love?wave amplitudes typically exceed those for Rayleigh waves suggests that the explanation for rapid?onset dynamic triggering may not reside solely with a simple static?threshold friction mode. The results also indicate that normal faults should be more susceptible to dynamic triggering by 20?s Rayleigh?wave stresses than thrust faults in the shallow seismogenic crust (<10??km) while the advantage tips in favor of reverse faults greater depths. This transition depth scales with wavelength and coincides roughly with the transition from retrograde?to?prograde particle motion. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems. The result is consistent with the apparent elevated susceptibility of extensional or transtensional tectonic regimes to remote triggering by Rayleigh?wave dynamic stresses than compressional or transpressional regimes.
Hollik, Wolfgang Gregor
2015-01-01
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 mu Yb in a non-trivial way. Contrary to famous A-parameter bounds, we relate the bottom Yukawa coupling with the supersymmetry breaking masses. The exclusion follows from the ...
Runge-Lenz vector in the Calogero-Coulomb problem
NASA Astrophysics Data System (ADS)
Hakobyan, Tigran; Nersessian, Armen
2015-08-01
We construct the Runge-Lenz vector and the symmetry algebra of the rational Calogero-Coulomb problem using the Dunkl operators. We reveal that they are proper deformations of their Coulomb counterpart. Together with similar correspondence between the Calogero oscillator and oscillator models, this observation permits the claim that most of the properties of the Coulomb and oscillator systems can be lifted to their Calogero-extended analogs by the proper replacement of the momenta by the Dunkl momenta operators.
Dynamical realization of democratic Yukawa matrices and alignment of A terms
NASA Astrophysics Data System (ADS)
Kobayashi, Tatsuo; Omura, Yuji; Terao, Haruhiko
2006-09-01
We study realization of the democratic form of Yukawa matrices by infrared fixed points. We investigate renormalization-group flows of Yukawa couplings in models with a single Yukawa matrix for three families, and up and down-sector Yukawa matrices. It is found that each model has its certain pattern of renormalization-group flows of Yukawa matrices. We apply them to the charged lepton sector and quark sector, and examine in which situation our class of models can lead to realistic results for the mass ratios and mixing angles between the second and third families. We also study corresponding A-terms. The A-terms approach toward the universal form with no physical CP-violating phase. Thus, constraints due to various neutral flavor changing processes except for ??e? are found to be satisfied by this dynamics. In order to suppress the electric dipole moments as well as ??e? sufficiently, more alignment of the A-terms with some reason is required.
Parabolic Sturmians approach to the three-body continuum Coulomb problem
S. A. Zaytsev; Yu. V. Popov; B. Piraux
2011-08-22
The three-body continuum Coulomb problem is treated in terms of the generalized parabolic coordinates. Approximate solutions are expressed in the form of a Lippmann-Schwinger type equation, where the Green's function includes the leading term of the kinetic energy and the total potential energy, whereas the potential contains the non-orthogonal part of the kinetic energy operator. As a test of this approach, the integral equation for the $(e^-,\\, e^-,\\, {{He}^{++}})$ system is solved numerically by using the parabolic Sturmian basis representation of the (approximate) potential. Convergence of the expansion coefficients of the solution is obtained as the basis set used to describe the potential is enlarged.
Equation of state for magnetized Coulomb plasmas
NASA Astrophysics Data System (ADS)
Potekhin, A. Y.; Chabrier, G.
2013-02-01
We have developed an analytical equation of state (EOS) for magnetized fully-ionized plasmas that 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 have constructed 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 approximations has been made publicly available. Using this code, we calculate and discuss the effects of electron screening and magnetic quantization on the position of the melting point in a range of densities and magnetic fields relevant to white dwarfs and outer envelopes of neutron stars. We consider also the thermal and mechanical structure of a magnetar envelope and argue that it can have a frozen surface which covers the liquid ocean above the solid crust. The Fortran code that realizes the analytical approximations described in this paper is available at http://www.ioffe.ru/astro/EIP/ and at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/550/A43
NASA Astrophysics Data System (ADS)
Ootuka, Y.
1998-03-01
A role of the magnetism upon the single electron transport was investigated in a single electron transistor (SET) made of ferromagnetic metals. The system consisted of a small Co island connected to Ni leads via thin NiO tunnel barriers. The zero bias resistance showed the Coulomb oscillations as a function of the gate voltage at low temperatures. The device had a characteristic magnetoresistance (MR): When a large biasing current was applied, the magnetic valve effect with MR ratio 3.6% appeared. In Coulomb blockade regime, the ON-resistance had essentially the same MR, but the OFF-state MR was extremely enhanced and exceeded even 40%. This enhancement is analyzed in terms of the effective charging energy which depends on tunnel resistance. We also found a monotonic phase shift of the Coulomb oscillations in the magnetic field, which resulted in the Coulomb oscillations as a function of the magnetic field at a fixed gate voltage. This phenomenon is explained in terms of a magnetic-field-induced change in the electrochemical potential of electrons. reference
Renormalized energy equidistribution and local charge balance in 2D Coulomb systems
Simona Rota Nodari; Sylvia Serfaty
2014-02-12
We consider two related problems: the first is the minimization of the "Coulomb renormalized energy" of Sandier-Serfaty, which corresponds to the total Coulomb interaction of point charges in a uniform neutralizing background (or rather variants of it). The second corresponds to the minimization of the Hamiltonian of a two-dimensional "Coulomb gas" or "one-component plasma", a system of n point charges with Coulomb pair interaction, in a confining potential (minimizers of this energy also correspond to "weighted Fekete sets"). In both cases we investigate the microscopic structure of minimizers, i.e. at the scale corresponding to the interparticle distance. We show that in any large enough microscopic set, the value of the energy and the number of points are "rigid" and completely determined by the macroscopic density of points. In other words, points and energy are "equidistributed" in space (modulo appropriate scalings). The number of points in a ball is in particular known up to an error proportional to the radius of the ball. We also prove a result on the maximal and minimal distances between points. Our approach involves fully exploiting the minimality by reducing to minimization problems with fixed boundary conditions posed on smaller subsets.
Two-body Coulomb problems with sources
Gasaneo, G.; Ancarani, L. U.
2010-10-15
The two-body Coulomb Schroedinger equation with different types of nonhomogeneities are studied. The particular solution of these nonhomogeneous equations is expressed in closed form in terms of a two-variable hypergeometric function. A particular representation of the latter allows one to study efficiently the solution in the asymptotic limit of large values of the coordinate and hence the associated physics. Simple sources are first considered, and a complete analysis of scattering and bound states is performed. The solutions corresponding to more general (arbitrary) sources are then provided and written in terms of more general hypergeometric functions.
Multiple Coulomb scattering in thin silicon
NASA Astrophysics Data System (ADS)
Berger, N.; Buniatyan, A.; Eckert, P.; Förster, F.; Gredig, R.; Kovalenko, O.; Kiehn, M.; Philipp, R.; Schöning, A.; Wiedner, D.
2014-07-01
We present a measurement of multiple Coulomb scattering of 1 to 6 GeV/c electrons in thin (50-140 ?m) silicon targets. The data were obtained with the EUDET telescope Aconite at DESY and are compared to parametrisations as used in the Geant4 software package. We find good agreement between data and simulation in the scattering distribution width but large deviations in the shape of the distribution. In order to achieve a better description of the shape, a new scattering model based on a Student's t distribution is developed and compared to the data.
Coulomb Explosion Imaging with Shaped Pulses
NASA Astrophysics Data System (ADS)
Wang, Z.; Chen, G. Y.; Minker, G.; Iacangelo, S.; Hill, W. T., III
2008-05-01
Pulse shaping has wide application from coherent control of chemical reactions to quantum computing. We have built a system capable of creating and characterizing optimized pulse shapes with large bandwidths -- > 25 nm. Phase and amplitude shaping are controlled with a liquid crystal spatial light modulator (SLM) while a combination of spectral interferometry techniques -- FROG, SPIDER, and SEA TADPOLE -- are exploited to reconstruct the temporal and spectral phase along with the amplitude of the electric field. Optimized shapes are generated via closed-loop feedback, enabled by a Genetic Algorithm (GA). This poster outlines the application of the GA in combination with Coulomb explosion imaging of small molecular systems.
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.
Expectation values in relativistic Coulomb problems
NASA Astrophysics Data System (ADS)
Suslov, Sergei K.
2009-09-01
We evaluate the matrix elements langOrprang, where O =\\left\\{1,\\beta,i{\\bm \\alpha \\bf n}\\beta \\right\\} are the standard Dirac matrix operators and the angular brackets denote the quantum-mechanical average for the relativistic Coulomb problem, in terms of generalized hypergeometric functions 3F2(1) for all suitable powers. Their connections with the Chebyshev and Hahn polynomials of a discrete variable are emphasized. As a result, we derive two sets of Pasternack-type matrix identities for these integrals, when p ? -p - 1 and p ? -p - 3, respectively. Some applications to the theory of hydrogenlike relativistic systems are reviewed.
Mathematical structure of relativistic Coulomb integrals
Suslov, Sergei K.
2010-03-15
We show that the diagonal matrix elements
NASA Astrophysics Data System (ADS)
Barnhart, W. D.; Lohman, R. B.
2009-05-01
In this research, we examine the Coulomb stress changes that occurred between two earthquakes (Mw 5.9, Nov. 7, 2005 and Mw 6.0, Sep 10, 2008) on Qeshm Island in the Iranian Zagros Mountains. Coulomb stress change has been proposed as a possible mechanism that may advance or retard the timing of ruptures of adjacent faults following an earthquake event. While magnitudes of Coulomb stress changes are often small compared to total seismic stress releases, they may accelerate the timing of rupture on faults nearing their critical failure state. Using inversions of Interferometric Synthetic Aperture Radar (InSAR), we present various potential slip distributions for each event as well as a range of fault plane solutions that are consistent with the data. From our family of models of slip and orientation for each faulting surface we calculate the Coulomb stress change on the 2008 fault surface caused by the 2005 event using the program Coulomb 3.1. Preliminary results indicate that, depending on the models used, the region where maximum slip occurred during the 2008 event can be associated with either positive or negative Coulomb stress changes due to the 2005 earthquake. This suggests that further a priori constraints are necessary to better constrain fault orientations and slip distributions, or that other post-seismic recovery mechanisms are needed to accurately model the stress evolution of the 2008 fault plane and other potential faults within the region. We then build on our models of Coulomb stress drop through finite element models of dynamic stress evolution to explore the relationship between stress fields in bedrock and local salt domes.
Effect of Coulomb interaction on multi-electronwave packet dynamics
Shiokawa, T. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8571 (Japan); Takada, Y. [Faculty of Engineering, Tokyo University of Science, Chiyoda, Tokyo, 102-0073, Japan and CREST, Japan Science and Technology Agency (Japan); Konabe, S.; Hatsugai, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8571, Japan and CREST, Japan Science and Technology Agency (Japan); Muraguchi, M. [Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan and CREST, Japan Science and Technology Agency (Japan); Endoh, T. [Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan and Center for Spintronics Integrated Systems, Tohoku University, Sendai, 980-8577, Japan and CREST, Japan Science and Technology Agency (Japan); Shiraishi, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8571, Japan and Center for Computational Science, University of Tsukuba, Tsukuba, 305-8577, Japan and CREST, Japan Science and Technology Agency (Japan)
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.
'Complete' measurement of molecular Coulomb-explosions
Werner, U.; Lutz, H. O.
1996-02-25
The multiple ionization and fragmentation of small molecules, e.g. H2, D2, H2O, and CF4, by fast H{sup +}, He{sup +}, and highly charged O{sup q+}-ions was studied utilizing a position- and time-sensitive multi-particle detector. The coincident measurement of the momenta of correlated fragment-ions yields a kinematically complete image of the molecular break-up process. Thereby, apart from relative cross-sections for specific reaction channels, the fragmentation energy as well as angular correlations can be derived for each individual event. Of special interest are 'Coulomb-explosion' processes like H2{yields}H{sup +}+H{sup +} or H2O{yields}H{sup +}+H{sup +}+O{sup n+}. Whereas the H2 and D2 data are in good agreement with a pure Coulomb-explosion model, this model is insufficient to explain the detailed behaviour of more complex systems. In case of H2O better agreement is achieved with ab initio MCSCF-calculations of the intermediate H2O{sup (n+2)+} parent-ion.
Thermodynamic properties of screened Coulomb balls
NASA Astrophysics Data System (ADS)
Bonitz, M.; Baumgartner, H.; Filinov, A.
2006-10-01
Complex plasmas in parabolic traps [1,2], especially Coulomb balls, can easily reach a strongly coupled state which is of great current interest in many fields, including trapped ions, ultracold plasmas and condensed matter. The advantage of the dust crystals is the direct experimental access to the individual particle positions, allowing for precision comparisons with theoretical models and numerical simulations. In this work the dependence of melting points of mesoscopic spherical crystals on the screening and particle number is analyzed. We present analytical results which are compared with simulation and experimental data [3,4,5]. It is shown that the influence of the screening on structural properties of these mesoscopic systems exhibts also a strong impact on the melting behavior. This analysis is based on Metropolis thermodynamic Monte Carlo simulations to obtain first principle thermodynamic properties of the strongly correlated Coulomb clusters. Finally, our results allow to propose a new non-invasive diagnostic to determine the dust temperature. [1] O. Arp, A. Piel and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004).[2] P. Ludwig, S. Kosse and M. Bonitz, Phys. Rev. E 71, 046403 (2005).[3] M. Bonitz, D. Block, O. Arp, V. Golunychiy, H. Baumgartner, P. Ludwig, A. Piel and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006). [4] O.S. Vaulina, S.A. Khrapak and G.E. Morfill, Phys. Rev. E 66, 016404 (2002). [5] J.P. Schiffer, Phys. Rev. Lett. 88, 205003 (2002)
Non-homogeneous solutions of a Coulomb Schrödinger equation as basis set for scattering problems
Del Punta, J. A.; Ambrosio, M. J.; Gasaneo, G.; Zaytsev, S. A.; Ancarani, L. U.
2014-05-15
We introduce and study two-body Quasi Sturmian functions which are proposed as basis functions for applications in three-body scattering problems. They are solutions of a two-body non-homogeneous Schrödinger equation. We present different analytic expressions, including asymptotic behaviors, for the pure Coulomb potential with a driven term involving either Slater-type or Laguerre-type orbitals. The efficiency of Quasi Sturmian functions as basis set is numerically illustrated through a two-body scattering problem.
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].
Non-minimal coupling in Higgs-Yukawa model with asymptotically safe gravity
Oda, Kin-ya
2015-01-01
We study the fixed point structure of the Higgs-Yukawa model, with its scalar being non-minimally coupled to the asymptotically safe gravity, using the functional renormalization group. We have obtained the renormalization group equations for the cosmological and Newton constants, the scalar mass-squared and quartic coupling constant, and the Yukawa and non-minimal coupling constants, taking into account all the scalar, fermion, and graviton loops. We find that switching on the fermionic quantum fluctuations makes the non-minimal coupling constant irrelevant around the Gaussian-matter fixed point with the asymptotically safe gravity.
Yukawa Interactions and Dynamical Generation of Mass in an External Magnetic Field
Efrain J. Ferrer; Vivian de la Incera
1998-07-01
In this work we study the dynamical generation of a fermion mass induced by a constant and uniform external magnetic field in an Abelian gauge model with a Yukawa term. We show that the Yukawa coupling not only enhances the dynamical generation of the mass, but it substantially decreases the magnetic field required for the mass to be generated at temperatures comparable to the electroweak critical temperature. These results indicate that if large enough primordial magnetic fields were present during the early universe evolution, the field-induced generation of fermion masses, which in turn corresponds to the generation of fermion bound states, may play an important role in the electroweak phase transition.
New constraints on Yukawa-type interactions from the Casimir effect
V. M. Mostepanenko; V. B. Bezerra; G. L. Klimchitskaya; C. Romero
2012-01-27
Measurements of the Casimir force are used to obtain stronger constraints on the parameters of hypothetical interactions predicted in different unification schemes beyond the Standard Model. We review new strong constraints on the Yukawa-type interactions derived during the last two years from recent experiments on measuring the lateral Casimir force, Casimir force in configurations with corrugated boundaries and the Casimir-Polder force. Specifically, from measurements of the lateral Casimir force compared with the exact theory the strengthening of constraints up to a factor of 24 millions was achieved. We also discuss further possibilities to strengthen constraints on the Yukawa interactions from the Casimir effect.
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.
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.
Non-minimal coupling in Higgs-Yukawa model with asymptotically safe gravity
Kin-ya Oda; Masatoshi Yamada
2015-10-13
We study the fixed point structure of the Higgs-Yukawa model, with its scalar being non-minimally coupled to the asymptotically safe gravity, using the functional renormalization group. We have obtained the renormalization group equations for the cosmological and Newton constants, the scalar mass-squared and quartic coupling constant, and the Yukawa and non-minimal coupling constants, taking into account all the scalar, fermion, and graviton loops. We find that switching on the fermionic quantum fluctuations makes the non-minimal coupling constant irrelevant around the Gaussian-matter fixed point with the asymptotically safe gravity.
Tan(beta) enhanced Yukawa couplings for supersymmetric Higgs singlets at one loop
Robert N. Hodgkinson
2007-10-23
Extensions of the MSSM generically feature gauge singlet Higgs bosons. These singlet Higgs bosons have tan(beta)-enhanced Yukawa couplings to down-type quarks and leptons at the one-loop level. We present an effective Lagrangian incorporating these Yukawa couplings and use it to study their effect on singlet Higgs boson phenomenology within both the mnSSM and NMSSM. It is found that the loop-induced couplings represent an appreciable effect for the singlet pseudoscalar in particular, and may dominate its decay modes in some regions of parameter space.
Nonadiabatic Coulomb effects in strong-field ionization in circularly polarized laser fields
NASA Astrophysics Data System (ADS)
Kaushal, Jivesh; Smirnova, Olga
2013-07-01
We develop the recently proposed analytical R-matrix (ARM) method to encompass strong-field ionization by circularly polarized fields, for atoms with arbitrary binding potentials. Through the ARM method, the effect of the core potential can now be included consistently both during and after ionization. We find that Coulomb effects modify the ionization dynamics in several ways, including modification of (i) the ionization times, (ii) the initial conditions for the electron continuum dynamics, (iii) the “tunneling angle” at which the electron “enters” the barrier, and (iv) the electron drift momentum. We derive analytical expressions for the Coulomb-corrected ionization times, initial velocities, momentum shifts, and ionization rates in circularly polarized fields, for arbitrary angular momentum of the initial state. We also analyze how nonadiabatic Coulomb effects modify (i) the calibration of the attoclock in the angular streaking method and (ii) the ratio of ionization rates from p- and p+ orbitals, predicted by Barth and Smirnova [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.84.063415 84, 063415 (2011)] for short-range potentials.
Quantifying the {sup 12}C+{sup 12}C sub-Coulomb fusion with the time-dependent wave-packet method
Diaz-Torres, Alexis; Wiescher, Michael
2012-10-20
This contribution provides a preliminary study of the {sup 12}C+{sup 12}C sub-Coulomb fusion reaction using the time-dependent wave-packet method within a nuclear molecular picture. 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.
Numerical experiments for Coulomb's law particle flow for nonlinear filters
Fred Daum; Jim Huang; Arjang Noushin
2011-01-01
We show numerical results for a new nonlinear filtering algorithm that is analogous to Coulomb's law. We have invented a new theory of exact particle flow for nonlinear filters. The flow of particles corresponding to Bayes' rule is computed from the gradient of the solution of Poisson's equation, and it is analogous to Coulomb's law. Our theory is a radical
Dynamical effects in the Coulomb expansion following nuclear fragmentation
Chung, K.C.; Donangelo, R.; Schechter, H.
1987-09-01
The effects of the Coulomb expansion on the fragment kinetic energy spectrum for a fragmentating hot nuclear system is investigated. In particular, /sup 12/C-fragment spectra are calculated and compared with those predicted by the uniform expansion approximation. The results indicate that the energy spectra of fragments are quite sensitive to the details of the Coulomb expansion treatment.
Coulomb crystals in neutron star crust D. A. Baiko
Coulomb crystals in neutron star crust D. A. Baiko A.F. Ioffe Physical Technical Institute, Saint in a wide range of mass densities and temperatures is in a crystal state. At a given density, the crystal crystal model. In this talk we analyze thermodynamic and elastic properties of the Coulomb crystals
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…
Physics Calendar from Yukawa Inst for Theor Phys field A:Astrophysics E:Elementary Particle N 3:00 pm Seminar field:E/lang:J Seminar Room K202, Yukawa Institute, Kyoto NonPerturbative Aspects:N/lang:J Seminar Room K202, Yukawa Institute, Kyoto Hydrodynamical evolution near the QCD critical end point Nonaka
The Examination of the {sup 12}C + {sup 24}Mg Elastic Scattering around the Coulomb Barrier
Boztosun, I.; Dagdemir, Y.; Bayrak, O. [Department of Physics, Erciyes University, Kayseri (Turkey)
2005-07-01
The investigation of nuclear reactions near the Coulomb barrier poses a number of problematic issues which have remained unsolved for a long time: The out-of-phase problem between theoretical predictions and experimental data, the reproduction of the oscillatory structure near the Coulomb barrier, and the consistent description of angular distributions together with the excitation functions data are just some of these issues. To address and overcome them, we examine the elastic scattering of the {sup 12}C + {sup 24}Mg system within the framework of the optical model with two small potentials in addition to the nuclear potential. The experimental data have been analyzed in the laboratory system from 16.0 to 24.0 MeV and excellent agreement between theoretical results and the measured experimental data has been obtained by using this modified optical potential. We show that the presence of the two small additional potentials creates a deepening in the surface region of the nuclear potential, which is very effective for the interference of the internal and barrier waves. This work is important in showing the sensitivity of the cross section to the fine details of the optical potential. It is also argued that the two small additional potentials take into account the coupling effect like that of the coupled channels and as a result reduce the strength of the imaginary potential. In this context, the results of the optical model are compared with that of the coupled channels.
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.
Virial coefficients and vapor-liquid equilibria of the EXP6 and 2-Yukawa fluids
J. Krejcí; I. Nezbeda; R. Melnyk; A. Trokhymchuk
2011-07-20
Virial coefficients $B_2$ through $B_4$ and the vapor-liquid equilibria for the EXP6 and 2-Yukawa (2Y) fluids have been determined using numerical integrations and Gibbs ensemble simulations, respectively. The chosen 2Y models have been recently determined as an appropriate reference fluid for the considered EXP6 models.