Journal articles: 'Approximation de la masse effective'

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Uechi, Schun T., and Hiroshi Uechi. "The Density-Dependent Correlations among Observables in Nuclear Matter and Hyperon-Rich Neutron Stars." Advances in High Energy Physics 2009 (2009): 1–15. http://dx.doi.org/10.1155/2009/640919.

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The conservingσ-ω-ρmean-field approximation with nonlinear interactions of hadrons has been applied to examine properties of nuclear matter and hyperonic neutron stars. The nonlinear interactions that will produce density-dependent effective masses and coupling constants of hadrons are included in order to examine density correlations among properties of nuclear matter and neutron stars such as binding energy, incompressibility,K, symmetry energy,a4, hyperon-onset density, and maximum masses of neutron stars. The conditions of conserving approximations in order to maintain thermodynamic consistency to an approximation are essential for the analysis of density-dependent correlations.

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Franz, Christian, Marcel Giar, Markus Heinemann, Michael Czerner, and Christian Heiliger. "Band Structure and Effective Masses of Zn1-xMgxO." MRS Proceedings 1494 (2012): 57–63. http://dx.doi.org/10.1557/opl.2012.1709.

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ABSTRACTWe analyze the influence of the Mg concentration on several important properties of the band structure of Zn1-xMgxO alloys in wurtzite structure using ab initio calculations. For this purpose, the band structure for finite concentrations is defined in terms of the Bloch spectral density, which can be calculated within the coherent potential approximation. We investigate the concentration dependence of the band gap and the crystal-field splitting of the valence bands. The effective electron and hole masses are determined by extending the effective mass model to finite concentrations. We compare our results with experimental results and other calculations.

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Hejlová, A., and J. Blahovec. "The modified CPEM (cooked potato effective mass) method: an instrumental assessment of potato sloughing." Czech Journal of Food Sciences 28, No. 5 (October 14, 2010): 407–11. http://dx.doi.org/10.17221/225/2008-cjfs.

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The cooked potato effective mass (CPEM) method for potato sloughing assessment involves cooking the potato flakes on the sieve in a stirred water bath and periodically determining their effective mass during cooking. The final cooking curve divided into the cooking and breaking parts provides two parameters: the cooking time (CT) is the time required for starting disintegration, while the slope of the breaking part (SBP) describes the disintegration rate. The method enables a detailed analysis of the cooking properties in relation to the tuber density. The modified analysis of the cooking curve is based on polynomial approximation of the breaking part. It provides the time of cooking (CT<sub>max</sub>) required to reach the maximal disintegration rate (MDR). These new parameters represent an alternative to the existing ones, their values are easier to obtain from the individual cooking curves, and therefore they can serve as a base for further development of the CPEM tests.  

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SHU, SONG, and JIA-RONG LI. "THE CJT CALCULATION IN STUDYING NUCLEAR MATTER BEYOND MEAN FIELD APPROXIMATION." Modern Physics Letters A 23, no. 21 (July 10, 2008): 1769–80. http://dx.doi.org/10.1142/s0217732308025814.

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We have introduced the Cornwall–Jackiw–Tomboulis (CJT) resummation scheme in studying nuclear matter. Based on the CJT formalism and using Walecka model, we have derived a set of coupled Dyson equations of nucleons and mesons. Neglecting the medium effects of the mesons, the usual mean field theory (MFT) results can be obtained. The beyond MFT calculations have been performed by thermodynamic consistently determining the meson effective masses and solving the coupled gap equations for nucleons and mesons together. The numerical results for the nucleon and meson effective masses at finite temperature and chemical potential in nuclear matter are discussed.

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Bouhassoune, Mohammed, and Arno Schindlmayr. "Ab InitioStudy of Strain Effects on the Quasiparticle Bands and Effective Masses in Silicon." Advances in Condensed Matter Physics 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/453125.

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Usingab initiocomputational methods, we study the structural and electronic properties of strained silicon, which has emerged as a promising technology to improve the performance of silicon-based metal-oxide-semiconductor field-effect transistors. In particular, higher electron mobilities are observed inn-doped samples with monoclinic strain along the [110] direction, and experimental evidence relates this to changes in the effective mass as well as the scattering rates. To assess the relative importance of these two factors, we combine density-functional theory in the local-density approximation with theGWapproximation for the electronic self-energy and investigate the effect of uniaxial and biaxial strains along the [110] direction on the structural and electronic properties of Si. Longitudinal and transverse components of the electron effective mass as a function of the strain are derived from fits to the quasiparticle band structure and a diagonalization of the full effective-mass tensor. The changes in the effective masses and the energy splitting of the conduction-band valleys for uniaxial and biaxial strains as well as their impact on the electron mobility are analyzed. The self-energy corrections withinGWlead to band gaps in excellent agreement with experimental measurements and slightly larger effective masses than in the local-density approximation.

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RAJASHABALA, S., and K. NAVANEETHAKRISHNAN. "EFFECTIVE MASSES FOR DONOR BINDING ENERGIES IN QUANTUM WELL SYSTEMS." Modern Physics Letters B 20, no. 24 (October 20, 2006): 1529–41. http://dx.doi.org/10.1142/s0217984906011633.

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The donor ionization energies in a quantum well and quantum dot with finite and infinite barriers are estimated for different well dimensions. Using the effective mass (EM) approximation, calculations are presented with constant effective mass and position dependent effective masses that are different for finite and infinite cases. Our results reduce to an approximate form used by X. H. Qi et al., Phys. Rev. B58 (1998) 10578 in the finite barrier model and that of L. E. Oliveira and L. M. Falicov, Phys. Rev. B34 (1986) 8676 in the infinite barrier case. Results are presented by taking the GaAs quantum well as an example. The use of constant effective mass of 0.067m0 is justified for well dimensions ≥a* where a* is an effective Bohr radius which is about 100 Å. While Qi et al. found a maximum of 22% variation in the binding energies due to mass variation, we obtained nearly 100% variation when mass variations are included correctly.

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BLOSSIER, B., G. VON HIPPEL, N. GARRON, and T. MENDES. "NONPERTURBATIVE HQET AT ORDER 1/m." International Journal of Modern Physics D 19, no. 08n10 (August 2010): 1661–66. http://dx.doi.org/10.1142/s0218271810017858.

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We summarize the first results for masses and decay constants of bottom-strange (pseudo-scalar and vector) mesons from nonperturbatively renormalized heavy-quark effective theory (HQET), using lattice-QCD simulations in the quenched approximation.

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LIU, JIN-LONG, and JING ZHU. "VALENCE ENERGY LEVEL STRUCTURE OF Si1-xGex/Si QUANTUM DISK." International Journal of Modern Physics B 23, no. 27 (October 30, 2009): 5251–59. http://dx.doi.org/10.1142/s0217979209053758.

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In the framework of the effective mass approximation, we develop a method to study the valence energy level structure of a Si 1-x Ge x/ Si quantum disk system in the adiabatic approximation using an exact diagonalization technique. The effects of strain, finite offset, and the difference between effective masses of holes in different materials are taken into account. The influences of both the height and the radius of the disk, and the content of Ge on the valence energy level structure of the quantum disk system are discussed. Our theoretical results are useful for researching and making low-dimensional semiconductor optoelectronic devices.

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Faizan, M., Hayat Ullah, S. H. Khan, Shahid M. Ramay, Salem A. S. Qaid, Asif Mahmood, and Manzar Ali. "Carrier effective masses and thermoelectric properties of novel Ag3AuSe2 and Ag3AuTe2 compounds." International Journal of Modern Physics B 31, no. 32 (December 18, 2017): 1750253. http://dx.doi.org/10.1142/s0217979217502538.

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The carrier effective masses as well as thermoelectric and electronic properties of ternary chalcogenides compounds of the form Ag3AuX2(X = Se, Te) have been studied using first-principles method based on density functional theory. For the treatment of exchange-correlation energy, we have used the generalized gradient approximation (GGA) by Perdew, Burke and Ernzerhof (PBE-GGA) and Wu–Cohen (WU-GGA) schemes. Both the compounds (Ag3AuSe2 and Ag3AuTe2) are direct bandgap semiconductors. The p-type nature of these compounds is confirmed by the effective mass calculations. In thermoelectric measurements, different parameters (electrical conductivity, carrier concentration, Seebeck coefficient, thermal conductivity and thermoelectric power) are calculated. It is found that all these parameters increase with the increase in temperature for both the compounds. The obtained results for these compounds such as the direct bandgap nature and their high value of the thermoelectric power make them valuable candidates for different device applications.

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Vintaikin, B. Е., O. V. Kondakov, and K. G. Ivanov. "Determining Anisotropic Material Properties by Means of Simulating Transmission in a Planar Waveguide." Herald of the Bauman Moscow State Technical University. Series Natural Sciences, no. 83 (2019): 51–63. http://dx.doi.org/10.18698/1812-3368-2019-2-51-63.

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The paper presents investigation results concerning a magneto-optic effect occurring in the far infrared range in bismuth. The investigation involves recording transmission in a planar waveguide located in a variable magnetic field. We ran a numerical simulation of the magneto-optic spectrum shapes in the relaxation-time approximation and determined a set of parameters for the electron energy spectrum in bismuth in the effective mass tensor approximation. We found that there is a discrete function describing how relaxation time and charge carrier concentration depend on the magnetic field magnitude. The function stems from the presence of electrons with different effective masses, which are concentrated in the three equivalent L points of the Brillouin zone, and holes in the T point of the Brillouin zone, which have topologically unconnected anisotropic constant energy surfaces

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Hussain, Eman Ali, Jamil A. Al-Hawasy, and Lamyaa Hussein Ali. "Finite Element Method Linear Triangular Element for Solving Nanoscale InAs⁄GaAs Quantum Ring Structures." Al-Mustansiriyah Journal of Science 30, no. 2 (September 30, 2019): 19. http://dx.doi.org/10.23851/mjs.v30i2.150.

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This paper concerned with the solution of the nanoscale structures consisting of the with an effective mass envelope function theory, the electronic states of the quantum ring are studied. In calculations, the effects due to the different effective masses of electrons in and out the rings are included. The energy levels of the electron are calculated in the different shapes of rings, i.e., that the inner radius of rings sensitively change the electronic states. The energy levels of the electron are not sensitively dependent on the outer radius for large rings. The structures of quantum rings are studied by the one electronic band Hamiltonian effective mass approximation, the energy- and position-dependent on electron effective mass approximation, and the spin-dependent on the Ben Daniel-Duke boundary conditions. In the description of the Hamiltonian matrix elements, the Finite elements method with different base linear triangular element is adopted. The non-linear energy confinement problem is solved approximately by using the Finite elements method with linear triangular element, to calculate the energy of the electron states for the quantum ring.

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12

Давыдов, С. Ю. "Низкоразмерные структуры карбида кремния: аналитические оценки характеристик электронного спектра." Физика и техника полупроводников 54, no. 5 (2020): 446. http://dx.doi.org/10.21883/ftp.2020.05.49257.9274.

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Abstract Using the Green’s function method within the tight-binding approximation, the electronic structure of an infinite silicon-carbide sheet, and nanoribbons and one-dimensional chains cut from it, is considered. Analytical expressions for band gaps, electron effective masses and characteristic velocities are derived. The effect of metal and dielectric substrates on the band characteristics is discussed.

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BHATTACHARYYA, ABHIJIT. "σ AND ω, WITH ∆-BARYON, AT HIGH TEMPERATURE." International Journal of Modern Physics E 05, no. 03 (September 1996): 511–20. http://dx.doi.org/10.1142/s0218301396000256.

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The temperature dependence of σ and ω meson effective masses due to the presence of Δ-baryon has been studied. Starting from the Walecka model, containing both nucleon and Δ, the temperature dependence of effective masses of nucleon and Δ have been calculated at the Mean Field (MF) level. These results have been used to calculate the contribution to the effective masses of σ and ω from both [Formula: see text]- and [Formula: see text]-loops in Random Phase Approximation (RPA). The results are quite interesting. The σ-meson mass increases due to the [Formula: see text] loop whereas it decreases due to [Formula: see text]-loop with temperature. Further, the change in σ-meson mass due to [Formula: see text]-loop is much more compared to that due to [Formula: see text]-loop. For the ω-meson, both the loops are responsible for the increase in mass with temperature.

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14

GLADYSHEV, A. V., and D. I. KAZAKOV. "RENORMALIZATION GROUP IMPROVED RADIATIVE CORRECTIONS TO THE SUPERSYMMETRIC HIGGS BOSON MASSES." Modern Physics Letters A 10, no. 40 (December 28, 1995): 3129–37. http://dx.doi.org/10.1142/s0217732395003288.

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The one-loop radiative corrections to the Higgs boson potential in the MSSM, originating from the top quark and squark loops, are summed in the leading log approximation using the renormalization group (RG). The RG improved effective potential is minimized and the corrections to the CP-odd and CP-even Higgs boson masses are calculated. The resulting masses exhibit smoother top mass dependence than those calculated without RG summation. We have also found that for preferable values of the top mass the light Higgs mass does not exceed 100 GeV.

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Kataev, A. L., and V. S. Molokoedov. "On the relation between pole and running heavy quark masses beyond the four-loop approximation." EPJ Web of Conferences 191 (2018): 04005. http://dx.doi.org/10.1051/epjconf/201819104005.

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The effective charges motivated method is applied to the relation between pole and M̅S̅-scheme heavy quark masses to study high order perturbative QCD corrections in the observable quantities proportional to the running quark masses. The non-calculated five- and six-loop perturbative QCD coefficients are estimated. This approach predicts for these terms the sign-alternating expansion in powers of number of lighter flavors nl, while the analyzed recently infrared renormalon asymptotic expressions do not reproduce the same behavior. We emphasize that coefficients of the quark mass relation contain proportional to π2 effects, which result from analytical continuation from the Euclidean region, where the scales of the running masses and QCD coupling constant are initially fixed, to the Minkowskian region, where the pole masses and the running QCD parameters are determined. For the t-quark the asymptotic nature of the non-resummed PT mass relation does not manifest itself at six-loops, while for the b-quark the minimal PT term appears at the probed by direct calculations four-loop level. The recent infrared renormalon based studies support these conclusions.

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Löfås, Henrik, Anton Grigoriev, Jan Isberg, and Rajeev Ahuja. "Effective masses and electronic structure of diamond including electron correlation effects in first principles calculations using the GW-approximation." AIP Advances 1, no. 3 (September 2011): 032139. http://dx.doi.org/10.1063/1.3630932.

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Ishii, N., H. Asami, W. Bentz, and K. Yazaki. "Faddeev Approach to the Nucleon in the NJL model." Australian Journal of Physics 50, no. 1 (1997): 123. http://dx.doi.org/10.1071/p96033.

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The nucleon and the delta are described as solutions of the relativistic Faddeev equation in the NJL model. We discuss the dependence of the baryon masses on the particular form of the four-Fermi interaction Lagrangians. Using the quark–diquark wave function, we calculate some bound state matrix elements such as the axial coupling constants, magnetic moments of the nucleon, the pion-nucleon sigma term and the proton-neutron mass difference. We also try to compare two pictures of describing the baryons in the NJL model, i.e. the mean-field approximation and the relativistic Faddeev approach. As a first step, we discuss how to improve the mean-field approximation by introducing an effective interaction. We also discuss the perturbative estimate of the deformation of the `vacuum" in the Faddeev approach.

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Подливаев, А. И. "Динамика распада водородных кластеров на поверхности графена и стоун-уэльсовского графена." Физика твердого тела 62, no. 12 (2020): 2181. http://dx.doi.org/10.21883/ftt.2020.12.50223.177.

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Green’s function method together with the tight-binding approach are used to get analytical estimations for the electron bands dispersions. The parabolic approximation is proposed which permits to find carriers effective masses and quantum capacitance. With the use of the Koster – Slater and Haldane – Anderson models the problem on the local states of defects is considered. Analytical estimates of the specific phonon frequencies and elastic constants are given. The obtained results are compared with the data available.

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Давыдов, С. Ю. "Модельные оценки свойств флюорографена." Физика твердого тела 63, no. 1 (2021): 158. http://dx.doi.org/10.21883/ftt.2021.01.50416.179.

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Green’s function method together with the tight-binding approach are used to get analytical estimations for the electron bands dispersions. The parabolic approximation is proposed which permits to find carriers effective masses and quantum capacitance. With the use of the Koster – Slater and Haldane – Anderson models the problem on the local states of vacancies is considered. Analytical estimates of the specific phonon frequencies and elastic constants are given. The obtained results are compared with the data available.

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Duan, Xiu Zhi, and Guang Xin Wang. "Electron in a Quantum Wire in the Presence of Parallel and Perpendicular Magnetic Fields." Applied Mechanics and Materials 380-384 (August 2013): 4837–40. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.4837.

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The electron states of self-assembled rectangular quantum wires (QWRs) are investigated in detail in the presence of a magnetic field. The calculations are done in the single band effective mass approximation. We study the electron states for the magnetic fields applied along and perpendicular to the wire, taking into account the different masses of the various particles inside and outside the QWRs. The electron energy and the influence of the magnetic field are discussed in this paper.

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MIZRACHI, LEAH. "FERMIONIC CONDENSATES IN SUPERSYMMETRIC COMPOSITE MODELS." Modern Physics Letters A 01, no. 05 (August 1986): 355–63. http://dx.doi.org/10.1142/s0217732386000440.

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Fermionic condensates are calculated in a background of instantons in a supersymmetric composite model based upon SU(2) hypercolor symmetry. Due to the effective 4-fermi interaction of the composites, the quasi-Goldstone fermion acquires a mass which is much smaller than ΛHC provided the gauge symmetry breaking scale, υ, is large enough for the approximation to be valid. (Typically υ≃eΛHC.) This provides a dynamical mechanism for generating the masses of quarks and leptons in this class of models.

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EL HAJ HASSAN, F., A. ALAEDDINE, M. ZOAETER, and I. RACHIDI. "FIRST-PRINCIPLES INVESTIGATION OF SnO2 AT HIGH PRESSURE." International Journal of Modern Physics B 19, no. 27 (October 30, 2005): 4081–92. http://dx.doi.org/10.1142/s0217979205032644.

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The ground state properties and the structural phase transformation of tin dioxide ( SnO 2) have been investigated using first principle full potential-linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). We used local density approximation (LDA) and the generalized gradient approximation (GGA), which are based on exchange-correlation energy optimization, to optimize the internal parameters by relaxing the atomic positions in the force directions and to calculate the total energy. For band structure calculations, we utilized both the Engel-Vosko's generalized gradient approximation (EVGGA), which optimizes the exchange-correlation potential, and also GGA. From the obtained band structures, the electron (hole) valance and conduction effective masses are deduced. For compressed volumes SnO 2 is shown to undergo two structural phase transitions with increasing pressure from the rutile- to the CaCl 2-type phase at 12.4 GPa and to a cubic phase, space group [Formula: see text] at 22.1 GPa. The calculated total energy allowed us to investigate several structural properties, in particular, the equilibrium lattice constants, bulk modulus, cohesive energy, interatomic distances and the angles between different atomic bonds. In addition, we discuss the bonding parameter in term of charge density, which show the localization of charge around the anion side.

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NESTERENKO, V. O., W. KLEINIG, J. KVASIL, P. VESELY, and P. G. REINHARD. "GIANT DIPOLE RESONANCE IN DEFORMED NUCLEI: DEPENDENCE ON SKYRME FORCES." International Journal of Modern Physics E 16, no. 02 (February 2007): 624–33. http://dx.doi.org/10.1142/s0218301307006071.

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The giant dipole resonance (GDR) in deformed nuclei is analyzed using the self-consistent separable random-phase-approximation (SRPA) with Skyrme forces SkT6, SkM*, SLy6 and SkI3. The deformed nuclei 150 Nd and 238 U are used as representative rare-earth and actinide samples. Dependences of the dipole strength distributions on some basic characteristics of the Skyrme functional and nuclear matter properties (isoscalar and isovector effective masses, time-odd contributions) are discussed. Particular attention is paid to the fragmentation structure of the GDR strength which is shown to depend sensitively to spin-orbit intruder states with large angular momentum.

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MENEZES, DÉBORA PERES, SIDNEY SANTOS AVANCINI, and CONSTANÇA PROVIDÊNCIA. "FINITE TEMPERATURE MATTER SUBJECT TO STRONG MAGNETIC FIELDS." International Journal of Modern Physics E 20, supp02 (December 2011): 93–99. http://dx.doi.org/10.1142/s0218301311040657.

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Quark matter at finite temperature and subject to strong magnetic fields is possibly present in the early stages of heavy ion collisions and in the interior of protoneutron stars. We use the mean field approximation to investigate this type of quark matter described by the Nambu–Jona-Lasinio model. The effect of the magnetic field on the effective quark masses and chemical potentials is only felt for quite strong magnetic fields, above 5 × 1018 G , with larger effects for the lower densities. Spin polarizations are more sensitive to weaker magnetic fields and are larger for lower temperatures and lower densities.

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KHANH, NGUYEN QUOC. "MAGNETOPLASMA OSCILLATIONS OF A TWO-DIMENSIONAL, TWO-COMPONENT PLASMA." Modern Physics Letters B 10, no. 16 (July 10, 1996): 737–44. http://dx.doi.org/10.1142/s0217984996000821.

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We investigate the magnetoplasma excitations in a system comprised of two parallel two-dimensional conducting layers separated by a distance 2d>0. The individual layers are assumed to have, in general, different effective masses, particle densities and charges. The dispersion equations are derived quantum mechanically within the random phase approximation and the spectrum of the long wavelength collective modes is calculated. We also investigate the mutual phase of two-dimensional magnetoplasma oscillations and show that this mutual phase is similar to that in the three-dimensional case and does not depend on the interlayer distance.

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MARTINEZ, A. PEREZ, A. ZEPEDA, and H. PEREZ ROJAS. "NEUTRINO SELF-ENERGY AND DISPERSION EQUATION IN DENSE MATTER." International Journal of Modern Physics A 11, no. 28 (November 10, 1996): 5093–108. http://dx.doi.org/10.1142/s0217751x96002352.

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General expressions for the neutrino self-energy and dispersion equations are found in a medium at finite temperature and density. The neutrino self-energy is calculated in the one-loop approximation and using the unitary gauge. The singularities and the absorption mechanisms are discussed. The low momentum (as compared with the vector boson masses) limit of the self-energy is obtained and from it, the dispersion equations for the quasiparticles are found. These solutions exhibit a group velocity smaller than unity which decreases with increasing density and an energy gap leading to a superfluid-type spectrum. In the particle–antiparticle asymmetric case, a negative effective mass is found for neutrinos.

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GUO, Z. Z., X. X. LIANG, and S. L. BAN. "PRESSURE EFFECT ON THE INTERFACE EXCITONS IN A TYPE-II ZnTe/CdSe HETEROJUNCTION." Modern Physics Letters B 17, no. 27n28 (November 30, 2003): 1425–35. http://dx.doi.org/10.1142/s0217984903006475.

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A variational method is used to study the ground-state binding energies of interface light-hole excitons in ZnTe/CdSe type-II heterojunctions under the influence of hydrostatic pressure. The finite triangle potential well approximation is introduced considering the band bending near the interface. The asymptotic transfer method is adopted to obtain the sub-band energies and wave functions of the electrons and light holes. The pressure influence on the band offsets, the effective masses and the dielectric constant are considered in the calculation. The obvious pressure-induced increase of the exciton binding energy is demonstrated and the influences of the pressure-depended parameters on the binding energy are compared.

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SAFONOV, VLADIMIR L. "CONDUCTION ELECTRON IN THE ANISOTROPIC MEDIUM." International Journal of Modern Physics B 07, no. 22 (October 10, 1993): 3899–905. http://dx.doi.org/10.1142/s0217979293003528.

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A new model for describing free electrons and holes in crystals in the long-wavelength approximation is proposed. The crystalline anisotropy in the framework of this model is introduced by means of corresponding space-time geometry. The generalized Dirac’s equation is constructed and non-relativistic Hamiltonian containing energy terms of the order of c–2 is calculated. It is shown that the spin magnetic components depend on corresponding effective cyclotron masses. Applicability of the results of the proposed model to different experiments is discussed. For the one-dimensional case, a hypothesis of para-Fermi statistics is suggested which may appear to explain one more mechanism of high-T c superconductivity.

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MIKHAIL, I. F. I., and S. B. A. EL-SAYED. "HYDROGENIC IMPURITY IN A QUANTUM WIRE: EFFECT OF DIFFERENT MASSES OF WIRE AND BARRIER." International Journal of Modern Physics B 23, no. 08 (March 30, 2009): 2107–25. http://dx.doi.org/10.1142/s0217979209049346.

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A variational calculation is given within the effective mass approximation of the binding energy of a hydrogenic donor impurity located on the axis of an infinitely long circular quantum well wire. A uniform magnetic field is applied along the axis of the wire. The different effective masses of the wire and the barrier are taken into consideration. This has not been done hitherto in the presence of the magnetic field. New analytical expressions for the electron energy levels and the binding energies of the hydrogenic impurity in the ground and the first four excited states have been derived. Moreover, the form of the binding energy reported in earlier works in the special case of zero magnetic field has been amended. A new form of the trial wavefunction has also been introduced. It has the advantage of satisfying the required boundary conditions in the case of different masses of the wire and barrier, and thus it resembles the exact solution in this respect. The new form of the trial wavefunction has been applied to the case of the ground state. It has improved the results of binding energy considerably as they tend to approach the exact solution from below.

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Bensaid, Djillali, Mohammed Ameri, Nadia Benseddik, Ali Mir, Nour Eddine Bouzouira, and Fethi Benzoudji. "Band Gap Engineering of Cd1-xBexSe Alloys." International Journal of Metals 2014 (May 13, 2014): 1–7. http://dx.doi.org/10.1155/2014/286393.

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The structural and electronic properties of the ternary Cd1-xBexSe alloys have been calculated using the full-potential linear muffin-tin-orbital (FP-LMTO) method based on density functional theory within local density approximation (LDA). The calculated equilibrium lattice constants and bulk moduli are compared with previous results. The concentration dependence of the electronic band structure and the direct and indirect band gaps are investigated. Moreover, the refractive index and the optical dielectric constant for Cd1-xBexSe are studied. The thermodynamic stability of the alloys of interest is investigated by means of the miscibility. This is the first quantitative theoretical prediction to investigate the effective masses, optical and thermodynamic properties for Cd1-xBexSe alloy, and still awaits experimental.

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Menezes, Debora. "Revisiting quark stars under the influence of strong magnetic fields." Proceedings of the International Astronomical Union 8, S291 (August 2012): 458. http://dx.doi.org/10.1017/s1743921312024507.

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AbstractQuark matter at finite temperature and subject to strong magnetic fields is possibly present in the early stages of heavy ion collisions and in the interior of protoneutron stars. We use the mean field approximation to investigate this type of quark matter described by the Nambu–Jona-Lasinio model. The energy per baryon of magnetized quark matter becomes more bound than nuclear matter made of iron nuclei, for magnetic fields around 1019 G. When the su(3) NJL model is applied to stellar matter, the maximum mass configurations are always above 1.45 solar masses and may be as high as 1.9 solar masses for a central magnetic field of 1018 G. These numbers are within the masses of observed neutron stars but exclude the recently measured star with 1.97 solar mass.The effect of the magnetic field on the effective quark masses and chemical potentials is only felt for quite strong magnetic fields, above 5 × 1018 G, with larger effects for the lower densities. Spin polarizations are more sensitive to weaker magnetic fields and are larger for lower temperatures and lower densities.

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PETER, A. JOHN. "THE EFFECT OF POSITION DEPENDENT EFFECTIVE MASS OF HYDROGENIC IMPURITIES IN PARABOLIC GaAs/GaAlAs QUANTUM DOTS IN A STRONG MAGNETIC FIELD." International Journal of Modern Physics B 23, no. 26 (October 20, 2009): 5109–18. http://dx.doi.org/10.1142/s0217979209053394.

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The binding energy of shallow hydrogenic impurities in parabolic GaAs/GaAlAs quantum dots is calculated as a function of dot radius in the influence of magnetic field. The binding energy has been calculated following a variational procedure within the effective-mass approximation. Calculations are presented with constant effective-mass and position dependent effective masses. A finite confining potential well with depth is determined by the discontinuity of the band gap in the quantum dot and the cladding. The results show that the impurity binding energy (i) increases as the dot radius decreases for the infinite case, (ii) reaches a peak value around 1R* as the dot radius decreases and then diminishes to a limiting value corresponding to the radius for which there are no bound states in the well for the infinite case, and (iii) increases with the magnetic field. Also it is found that (i) the use of constant effective mass (0.067 m0) is justified for dot sizes ≥ a* where a* is the effective Bohr radius which is about 100 Å for GaAs , in the estimation of ionization energy and (ii) the binding energy shows complicated behavior when the position dependent mass is included for the dot size ≤ a*. These results are compared with the available existing literatures.

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Lee, Jaehyun, Oves Badami, Hamilton Carrillo-Nuñez, Salim Berrada, Cristina Medina-Bailon, Tapas Dutta, Fikru Adamu-Lema, Vihar Georgiev, and Asen Asenov. "Variability Predictions for the Next Technology Generations of n-type SixGe1−x Nanowire MOSFETs." Micromachines 9, no. 12 (December 5, 2018): 643. http://dx.doi.org/10.3390/mi9120643.

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Using a state-of-the-art quantum transport simulator based on the effective mass approximation, we have thoroughly studied the impact of variability on Si x Ge 1 − x channel gate-all-around nanowire metal-oxide-semiconductor field-effect transistors (NWFETs) associated with random discrete dopants, line edge roughness, and metal gate granularity. Performance predictions of NWFETs with different cross-sectional shapes such as square, circle, and ellipse are also investigated. For each NWFETs, the effective masses have carefully been extracted from s p 3 d 5 s ∗ tight-binding band structures. In total, we have generated 7200 transistor samples and performed approximately 10,000 quantum transport simulations. Our statistical analysis reveals that metal gate granularity is dominant among the variability sources considered in this work. Assuming the parameters of the variability sources are the same, we have found that there is no significant difference of variability between SiGe and Si channel NWFETs.

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Wang, Guang Xin, and Xiu Zhi Duan. "Influence of Al Composition on Donor Impurity States in Self-Formed GaAs-Al_xGa_1-xAs Quantum Rings." Applied Mechanics and Materials 380-384 (August 2013): 4284–89. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.4284.

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Based on the the effective mass approximation and variational approach, the donor impurity states confined in self-formed GaAs/AlxGa1-xAs quantum rings (QRs) are investigated theoretically. A uniform electric field is applied along the growth direction of the QR. The different effective masses in the different regions of the GaAs/AlxGa1-xAs QR are taken into consideration. Numerical results show that the binding energy of a donor impurity increases gradually, reaches a maximum value, and then decreases quickly to the special value as the QR height decreases. Given a fixed QR size, the binding energy increases for the impurity located at the center of the QR when the Al composition increases. In addition, it can also be found that when the applied electric field strength increases, the donor binding energy increases for impurities localized at the negative z axis of the QR; however, the donor binding energy decreases slightly for impurities located at the center and positive z axis of the QR.

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SEN, SURAJIT, and B. BAGCHI. "CHIRAL AND UA(1) PHASE TRANSITIONS IN π0, η AND η′ MESONS." Modern Physics Letters A 21, no. 19 (June 21, 2006): 1529–39. http://dx.doi.org/10.1142/s0217732306019529.

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We have generalized the Pisarsky–Wilczek model of studying the UA(1) phase transition in π0, η and η′ system by incorporating the chiral phase transition. The mass-squared matrix of the neutral pseudoscalar mesons is revisited explicitly from the chiral effective action which necessitates the mixing among the unmixed states to get the physical states. The derivation of the mass spectra of the neutral pseudoscalar mesons shows that apart from their masses, the mixing angles also become temperature dependent. Based on the dilute instanton gas approximation we show that, the UA(1) phase transition along with the chiral phase transition plays an important role in the process of hadronization of the quark–gluon plasma with the quarks of three flavors.

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Gomes, William Silva, José Carlos Teixeira de Oliveira, Hilário Rodrigues, and Sérgio B. Duarte. "Delta Resonance Coupling with Walecka’s Mesons: Implications to Stellar Matter EoS." International Journal of Modern Physics: Conference Series 45 (January 2017): 1760034. http://dx.doi.org/10.1142/s2010194517600345.

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In this work we have obtained the equation of state to the highly asymmetric dense stellar matter, using the nonlinear Walecka model in the mean field approximation. We discussed the implication of changes in coupling constant of the delta baryonic resonance on the observable of the neutron star. A detailed analysis of the equation of state and of the baryonic effective mass in respect to changes in the delta coupling constants is carried out. We focus attention on a new aspect observed for pressure when varying the baryonic density of the medium; a first order phase transition like a liquid-gas phase transition was observed for an acceptable range of delta coupled constant values. We have explored the implication of this aspect for the neutron star structure and their maximum masses.

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NESTERENKO, V. O., W. KLEINIG, J. KVASIL, P. VESELY, and P. G. REINHARD. "TDDFT WITH SKYRME FORCES: EFFECT OF TIME-ODD DENSITIES ON ELECTRIC GIANT RESONANCES." International Journal of Modern Physics E 17, no. 01 (January 2008): 89–99. http://dx.doi.org/10.1142/s0218301308009586.

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Time-odd densities and their effect on electric giant resonances are investigated within the self-consistent separable random-phase-approximation (SRPA) for a variety of Skyrme forces (SkT6, SkO, SkM*, SIII, SGII, SLy4, SLy6, SkI3). Time-odd densities are essential for maintaining the Galilean invariance of the Skyrme functional. Their contribution is determined by the values and signs of the isovector and isoscalar effective-mass parameters of the force. In even-even nuclei these densities are not active in the ground state but can affect the dynamics. As a particular case, we explore the role of the current density in the description of isovector E1 and isoscalar E2 giant resonances in a chain of spherical and deformed Nd isotopes with A=134-158. The relation of the current to the effective masses and relevant parameters of the Skyrme functional is analyzed. It is shown that the current contributes substantially to E1 and E2 and the contribution is the same for all the isotopes along the chain, i.e. for both standard and exotic nuclei.

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Stumpf, H. "Formfactors of Relativistic Composite Particle Interactions in Unified Nonlinear Spinorfield Models." Zeitschrift für Naturforschung A 40, no. 7 (July 1, 1985): 752–73. http://dx.doi.org/10.1515/zna-1985-0717.

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Unified nonlinear spinorfield models are self-regularizing quantum field theories in which all observable (elementary and non-elementary) particles are assumed to be bound states of fermionic preon fields. Due to their large masses the preons themselves are confined and below the threshold of preon production the effective dynamics of the model is only concerned with bound state reactions. In preceding papers a functional energy representation, the statistical interpretation and the dynamical equations were derived and the effective dynamics for preon-antipreon boson states and three preon-fermion states (with corresponding anti-fermions) was studied in the low energy limit. The transformation of the functional energy representation of the spinorfield into composite particle functional operators produced a hierarchy of effective interactions at the composite particle level, the leading terms of which are identical with the functional energy representation of a phenomenological boson-fermion coupling theory. In this paper these calculations are extended into the high energy range. This leads to formfactors for the composite particle interaction terms which are calculated in a rough approximation and which in principle are observable. In addition, the mathematical and physical interpretation of nonlocal quantum field theories and the meaning of the mapping procedure, its relativistic invariance etc. are discussed.

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Martínez, Gerardo, and Peter Horsch. "A single hole in a quantum antiferromagnet: selfconsistent Green’s function approach." International Journal of Modern Physics B 05, no. 01n02 (January 1991): 207–17. http://dx.doi.org/10.1142/s0217979291000146.

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We solved numerically the integral equation for the selfenergy which describes the motion of a single hole in a two-dimensional quantum antiferromagnet (AF) within the selfconsistent Born approximation. This formulation stresses the similarity of the AF-spin polaron with the standard polaron problem. We confine our calculation to finite cluster geometries and compare with results from previous exact diagonalization studies. The spectral function is characterized by a narrow quasiparticle (qp) peak at the low energy side of the spectra, which appears to be well separated from the incoherent band part for large enough J values. For small J we find a reduced width of ~7t for the incoherent band. The bottom of the coherent qp band always occurs at (±π/2, ±π/2). Its bandwidth initially increases with J until J≃t and then decreases as 2t2/J. A complete characterization of our solution is given, including the dispersion relation and effective masses of this quasiparticle. The comparison with exact diagonalization studies for a 4×4 cluster is remarkably good. From our results we see that a lattice of 16×16 sites describes adequately the thermodynamic limit. We conclude that the simple Born approximation is a valuable scheme to characterize the dynamics of one hole in the t-J model. both in the perturbative and the strong coupling regimes.

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Bochorishvili, Beka, and Hariton M. Polatoglou. "Interacting Double InAs/GaAs Quantum Dots of Cylindrical Symmetry." Journal of Nano Research 10 (April 2010): 87–92. http://dx.doi.org/10.4028/www.scientific.net/jnanor.10.87.

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The electron and hole energy states and oscillator strengths for interband transitions of two interacting Quantum dots (QDs) are theoretically studied. We explore how the properties of the system depend on the distance between them. Calculations are done for InAs QDs which are embedded in GaAs. The QDs have cylindrical form and are situated one on top of the other in such way that their symmetry axes coincide. The calculations are done in the envelope function approximation using position dependent effective masses. Finite Element Method (FEM) is utilized to find energy spectra, wavefunctions and oscillator strengths. We find that the hole states show less tunneling compared to the electron states, transitions in general show some anisotropy which decreases as the distance between the dots decrease and that the total oscillator strength for each particular transition is constant.

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Mykhaylova, Valeriya. "Shear viscosity to electrical conductivity ratio in the quasiparticle models." European Physical Journal Special Topics 229, no. 22-23 (December 2020): 3487–96. http://dx.doi.org/10.1140/epjst/e2020-000116-9.

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AbstractWe examine the temperature dependence of the shear viscosity η to electrical conductivity σ ratio, as well as the specific shear viscosity and the scaled electrical conductivity in QCD with light and strange quarks. Our calculations are performed in kinetic theory under the relaxation time approximation combined with the quasiparticle model. We compute all transport parameters using the isotropic and transport cross sections and compare our results to a class of quasiparticle models for the QGP with Nf = 2 + 1. The results depending on different schemes are examined. The ratio (η∕s)∕(σ∕T) quantifies the relation between the relaxation times of gluons and quarks and specifies their comparative role in the evolution of the QGP. We find an excellent agreement with the (η∕s)∕(σ∕T) ratio deduced from the dynamical quasiparticle model in which the quasiparticles are characterized not only by their effective masses but also by finite widths.

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Bhandari, Uttam, Blaise Awola Ayirizia, Yuriy Malozovsky, Lashounda Franklin, and Diola Bagayoko. "First Principle Investigation of Electronic, Transport, and Bulk Properties of Zinc-Blende Magnesium Sulfide." Electronics 9, no. 11 (October 29, 2020): 1791. http://dx.doi.org/10.3390/electronics9111791.

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We have studied electronic, structural, and transport properties of zinc-blende magnesium sulfide (zb-MgS). We employed a local density approximation (LDA) potential and the linear combination of atomic orbitals (LCAO) method. Our computational method is able to reach the ground state of a material, as dictated by the second theorem of density functional theory (DFT). Consequently, our findings have the physical content of DFT and agree with available, corresponding experimental ones. The calculated band gap of zb-MgS, a direct gap equal to 4.43 eV, obtained at the experimental lattice constant of 5.620 Å, completely agrees with the experimental band gap of 4.45 ± 0.2 eV. We also report total (DOS) and partial (pDOS) densities of states, electron and hole effective masses, the equilibrium lattice constant, and the bulk modulus. The calculated pDOS also agree with the experiment for the description of the states at the top and the bottom of the valence and conduction bands, respectively.

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MARRANGHELLO, GUILHERME F., CESAR A. Z. VASCONCELLOS, MANFRED DILLIG, and J. A. DE FREITAS PACHECO. "A NUCLEAR MANY-BODY THEORY AT FINITE TEMPERATURE APPLIED TO A PROTONEUTRON STAR." International Journal of Modern Physics E 11, no. 02 (April 2002): 83–104. http://dx.doi.org/10.1142/s0218301302000727.

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Thermodynamical properties of nuclear matter are studied in the framework of an effective many-body field theory at finite temperature, considering the Sommerfeld approximation. We perform the calculations by using the nonlinear Boguta and Bodmer model, extended by the inclusion of the fundamental baryon octet and leptonic degrees of freedom. Trapped neutrinos are also included in order to describe protoneutron star properties through the integration of the Tolman–Oppenheimer–Volkoff equations, from which we obtain, beyond the standard relations for the masses and radii of protoneutron stars as functions of the central density, new results of these quantities as functions of temperature. Our predictions include: the determination of an absolute value for the limiting mass of protoneutron stars; new structural aspects on the nuclear matter phase transition via the behavior of the specific heat and, through the inclusion of quark degrees of freedom, the properties of a hadron-quark phase transition and hybrid protoneutron stars

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BEDNYAKOV, A. V. "ON THE TWO-LOOP DECOUPLING CORRECTIONS TO τ-LEPTON AND b-QUARK RUNNING MASSES IN THE MSSM." International Journal of Modern Physics A 25, no. 12 (May 10, 2010): 2437–56. http://dx.doi.org/10.1142/s0217751x10048494.

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Masses of heavy Standard Model (SM) fermions (top-quark, bottom-quark and tau-lepton) play an important role in the analysis of theories beyond the SM. They serve as low-energy input and reduce the parameter space of such theories. In this paper Minimal supersymmetric extension of the SM is considered and two-loop relations between known SM values of fermion masses and running parameters of the MSSM are studied within the effective theory approach. Both b-quark and τ-lepton have the same quantum numbers with respect to SU(2) group and in the MSSM acquire their masses due to interactions with the same Higgs doublet. As a consequence, for large values of tan β parameter corresponding Yukawa couplings also become large and together with tan β can significantly enhance radiative corrections. In the case of b-quark two-loop [Formula: see text] contribution to the relation between running bottom-quark mass in QCD and MSSM is known in literature. This paper is devoted to calculation of the NNLO corrections proportional to Yukawa couplings. For the τ-lepton obtained contribution can be considered as a good approximation to the full two-loop result. For the b-quark numerical analysis given in the paper shows that only the sum of strong and Yukawa corrections can play such a role.

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Chang, Pengying, Xiaoyan Liu, Fei Liu, and Gang Du. "Remote Phonon Scattering in Two-Dimensional InSe FETs with High-κ Gate Stack." Micromachines 9, no. 12 (December 19, 2018): 674. http://dx.doi.org/10.3390/mi9120674.

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This work focuses on the effect of remote phonon arising from the substrate and high-κ gate dielectric on electron mobility in two-dimensional (2D) InSe field-effect transistors (FETs). The electrostatic characteristic under quantum confinement is derived by self-consistently solving the Poisson and Schrödinger equations using the effective mass approximation. Then mobility is calculated by the Kubo–Greenwood formula accounting for the remote phonon scattering (RPS) as well as the intrinsic phonon scatterings, including the acoustic phonon, homopolar phonon, optical phonon scatterings, and Fröhlich interaction. Using the above method, the mobility degradation due to remote phonon is comprehensively explored in single- and dual-gate InSe FETs utilizing SiO2, Al2O3, and HfO2 as gate dielectric respectively. We unveil the origin of temperature, inversion density, and thickness dependence of carrier mobility. Simulations indicate that remote phonon and Fröhlich interaction plays a comparatively major role in determining the electron transport in InSe. Mobility is more severely degraded by remote phonon of HfO2 dielectric than Al2O3 and SiO2 dielectric, which can be effectively insulated by introducing a SiO2 interfacial layer between the high-κ dielectric and InSe. Due to its smaller in-plane and quantization effective masses, mobility begins to increase at higher density as carriers become degenerate, and mobility degradation with a reduced layer number is much stronger in InSe compared with MoS2.

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Ullah, Shahid, Hayat Ullah, Abdullah Yar, Sikander Azam, and A. Laref. "First-principles investigation of the electronic band structures and optical properties of quaternary ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) metal chalcogenides." International Journal of Modern Physics B 32, no. 30 (December 10, 2018): 1850337. http://dx.doi.org/10.1142/s021797921850337x.

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In this paper, we study the optoelectronic properties of quaternary metal chalcogenide semiconductor ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) compounds using state-of-the-art density functional theory (DFT) with TB-mBJ approximation for the treatment of exchange-correlation energy. In particular, the electronic and optical properties of the relaxed geometries of these compounds are investigated. Our first-principles ab-initio calculations show that the CsBaPS4 and RbBaPS4 compounds have direct bandgaps whereas the CsBaVS4 compound exhibits indirect bandgap nature. Importantly, the theoretically calculated values of the bandgaps of the compounds are consistent with experiment. Furthermore, our analysis of the electronic charge densities of these compounds indicates that the above quaternary chalcogenides have mixed covalent and ionic bonding characters. The effective masses of these compounds are also calculated which provide very useful information about the band structure and transport characteristics of the investigated compounds. Similarly, high absorptivity in the visible and ultraviolet regions of the electromagnetic spectrum possibly predicts and indicates the importance of these materials for potential optoelectronic applications in this range.

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Hamers, Adrian S. "Properties of von Zeipel–Lidov–Kozai oscillations in triple systems at the quadrupole order: relaxing the test particle approximation." Monthly Notices of the Royal Astronomical Society 500, no. 3 (November 11, 2020): 3481–96. http://dx.doi.org/10.1093/mnras/staa3498.

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ABSTRACT Von Zeipel–Lidov–Kozai (ZLK) oscillations in hierarchical triple systems have important astrophysical implications such as triggering strong interactions and producing, e.g. Type Ia supernovae and gravitational wave sources. When considering analytic properties of ZLK oscillations at the lowest (quadrupole) expansion order, as well as complications due to higher order terms, one usually assumes the test particle limit, in which one of the bodies in the inner binary is massless. Although this approximation holds well for, e.g. planetary systems, it is less accurate for systems with more comparable masses such as stellar triples. Although non-test-particle effects are usually taken into account in numerical simulations, a more analytic approach focusing on the differences between the test particle and general case (at quadrupole order) has, to our knowledge, not been presented. Here, we derive several analytic properties of secular oscillations in triples at the quadruple expansion order. The latter applies even to relatively compact triples, as long as the inner bodies are similar in mass such that octupole-order effects are suppressed. We consider general conditions for the character of the oscillations (circular versus librating), minimum and maximum eccentricities, and time-scales, all as a function of $\gamma \equiv (1/2) \, L_1/G_2$, a ratio of inner-to-outer orbital angular momenta variables (γ = 0 in the test particle limit). In particular, eccentricity oscillations are more effective at retrograde orientations for non-zero γ; assuming zero initial inner eccentricity, the maximum eccentricity peaks at $\cos (i_{\mathrm{rel},0}) = -\gamma$, where $i_{\mathrm{rel},0}$ is the initial relative inclination. We provide a python script that can be used to quickly compute these properties.

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MALOZOVSKY, Y., L. FRANKLIN, E. C. EKUMA, G. L. ZHAO, and D. BAGAYOKO. "AB-INITIO CALCULATIONS OF ELECTRONIC PROPERTIES OF InP AND GaP." International Journal of Modern Physics B 27, no. 15 (June 4, 2013): 1362013. http://dx.doi.org/10.1142/s0217979213620130.

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We present results from ab-initio, self-consistent local density approximation (LDA) calculations of electronic and related properties of zinc blende indium phosphide (InP) and gallium phosphide (GaP) . We employed a LDA potential and implemented the linear combination of atomic orbitals (LCAO) formalism. This implementation followed the Bagayoko, Zhao and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW–EF). This method searches for the optimal basis set that yields the minima of the occupied energies. This search entails increases of the size of the basis set and the related modifications of angular symmetry and of radial orbitals. Our calculated, direct band gap of 1.398 eV (1.40 eV), at the Γ point, is in excellent agreement with experimental values, for InP , and our preliminary result for the indirect gap of GaP is 2.135 eV, from the Γ to X high symmetry points. We have also calculated electron and hole effective masses for both InP and GaP . These calculated properties also agree with experimental findings. We conclude that the BZW–EF method could be employed in calculations of electronic properties of high-Tc superconducting materials to explain their complex properties.

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Dell’Anna, Luca, and Stefano Grava. "Critical Temperature in the BCS-BEC Crossover with Spin-Orbit Coupling." Condensed Matter 6, no. 2 (April 30, 2021): 16. http://dx.doi.org/10.3390/condmat6020016.

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We review the study of the superfluid phase transition in a system of fermions whose interaction can be tuned continuously along the crossover from Bardeen–Cooper–Schrieffer (BCS) superconducting phase to a Bose–Einstein condensate (BEC), also in the presence of a spin–orbit coupling. Below a critical temperature the system is characterized by an order parameter. Generally a mean field approximation cannot reproduce the correct behavior of the critical temperature Tc over the whole crossover. We analyze the crucial role of quantum fluctuations beyond the mean-field approach useful to find Tc along the crossover in the presence of a spin–orbit coupling, within a path integral approach. A formal and detailed derivation for the set of equations useful to derive Tc is performed in the presence of Rashba, Dresselhaus and Zeeman couplings. In particular in the case of only Rashba coupling, for which the spin–orbit effects are more relevant, the two-body bound state exists for any value of the interaction, namely in the full crossover. As a result the effective masses of the emerging bosonic excitations are finite also in the BCS regime.

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Viñas, Xavier, Claudia Gonzalez-Boquera, Mario Centelles, Chiranjib Mondal, and Luis M. Robledo. "Unified Equation of State for Neutron Stars Based on the Gogny Interaction." Symmetry 13, no. 9 (September 2, 2021): 1613. http://dx.doi.org/10.3390/sym13091613.

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The effective Gogny interactions of the D1 family were established by D. Gogny more than forty years ago with the aim to describe simultaneously the mean field and the pairing field corresponding to the nuclear interaction. The most popular Gogny parametrizations, namely D1S, D1N and D1M, describe accurately the ground-state properties of spherical and deformed finite nuclei all across the mass table obtained with Hartree–Fock–Bogoliubov (HFB) calculations. However, these forces produce a rather soft equation of state (EoS) in neutron matter, which leads to predict maximum masses of neutron stars well below the observed value of two solar masses. To remove this limitation, we built new Gogny parametrizations by modifying the density dependence of the symmetry energy predicted by the force in such a way that they can be applied to the neutron star domain and can also reproduce the properties of finite nuclei as good as their predecessors. These new parametrizations allow us to obtain stiffer EoS’s based on the Gogny interactions, which predict maximum masses of neutron stars around two solar masses. Moreover, other global properties of the star, such as the moment of inertia and the tidal deformability, are in harmony with those obtained with other well tested EoSs based on the SLy4 Skyrme force or the Barcelona–Catania–Paris–Madrid (BCPM) energy density functional. Properties of the core-crust transition predicted by these Gogny EoSs are also analyzed. Using these new Gogny forces, the EoS in the inner crust is obtained with the Wigner–Seitz approximation in the Variational Wigner–Kirkwood approach along with the Strutinsky integral method, which allows one to estimate in a perturbative way the proton shell and pairing corrections. For the outer crust, the EoS is determined basically by the nuclear masses, which are taken from the experiments, wherever they are available, or by HFB calculations performed with these new forces if the experimental masses are not known.

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Journal articles on the topic 'Approximation de la masse effective'

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