Showing papers on "Spin-½ published in 1973"
TL;DR: In this paper, the ground state energy of a system of interacting electrons is expressed as a functional function of the current density of the system, and a spin-dependent term which leads, in the nonrelativistic limit, to a local potential which is also spin dependent.
Abstract: This work is a generalization of the Hohenberg---Kohn---Sham theory of the inhomogeneous electron gas, with emphasis on spin effects. An argument based on quantum electrodynamics is used to express the ground-state energy of a system of interacting electrons as a functional of the current density. Expressions are derived for coefficients appearing in an expansion of the correlation functional in terms of the linear-response functions of the homogeneous system, for a gas of almost constant four-current density. The current density contains a spin-dependent term which leads, in the nonrelativistic limit, to a local potential which is also spin dependent. This potential is applied to the problems of spin splitting of energy bands in ferromagnets and spin-density-wave antiferromagnets. The relations between the present approach, that of Slater, and the collective electron theory of ferromagnetism of Stoner are described.
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TL;DR: In this article, the authors studied the interface between regions of opposite spin in the simple cubic Ising model and found that the interface width diverges at a temperature about half the critical temperature.
Abstract: We have studied the interface between regions of opposite spin in the simple cubic Ising model. Low-temperature expansions of moments of the gradient of the density profile and of the slope at its midpoint suggest that the interface width diverges at a temperature ${T}_{R}$ about half the critical temperature. We discuss the physical significance of this transition and implications for general theories of interfacial properties.
159 citations
TL;DR: A review of the theoretical and experimental work available until now with respect to spin paramagnetism in thin films is given in this paper, which includes a study of the excitation spectrum of thin films in a parallel magnetic field.
Abstract: Thin films provide an ideal means for studying the role of spin paramagnetism in the theory of superconductivity. A review is given of the theoretical and experimental work available until now with respect to this problem. It includes a study of the excitation spectrum of thin films in a parallel magnetic field and the experimental evidence of Zeeman splitting of superconducting quasiparticles. The role of spin-orbit interaction is discussed in detail. The application of spin selective tunnelling is shown. Furthermore, it includes a study of the order of phase transition between the normal state and the paramagnetically limited superconducting state. A detailed discussion is given of the generalized Ginzburg-Landau equation including numerical evaluations. The applicability of Tinkham's formula is discussed, which is relevant for the determination of critical fields of arbitrary orientations to the film. Finally, account is given of the work which deals with the influence of spin paramagnetism on...
157 citations
Journal Article•
TL;DR: In this paper, the introduction of gauge fields and the Higgs effect for Goldstone particles with spin 1/2 are considered, and the results show that they can be used to detect the presence of Higgs effects.
Abstract: Translated from Zh. Eksp. Teor. Fiz., Pis'ma Red.; 18: No. 8, The introduction of gauge fields and the Higgs effect for Goldstone particles with spin 1/2 are considered. (auth)
157 citations
TL;DR: In this article, a method for eliminating the off-diagonal lagrangian multipliers which appear in open-shell SCF theory is given, which leads to a set of coupled eigenvalue equations which can be easily solved for a new guess to the SCF orbitals.
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TL;DR: In this paper, the requirements of spin conservation in the form of a Ward identity, are exploited to make a selfconsistent theory of itinerant ferromagnetism in terms of electron-magnon interactions.
Abstract: The requirements of spin conservation in the form of a Ward identity, are exploited to make a selfconsistent theory of itinerant ferromagnetism in terms of electron-magnon interactions. Earlier results are extended to weak ferromagnets and the structure of self energies and single particle spectral weight functions is discussed. The theory is also applied to the calculation of the spin wave stiffness constant.
100 citations
TL;DR: In this paper, the authors examined the Bjorken scaling and Regge behaviours expected in the high enery inelastic scattering of polarized electrons on a polarized nucleon target, and showed that the usual expansion already fully includes the M ≠ 0 bilocals.
TL;DR: In this article, the spin projected Hartree-Fock equations are derived and discussed in the general (many λi) case, based on the corresponding generalized Brillouin theorem, substituting in its expression a spin projected DODS Slater determinant as a linear combination of determinants.
Abstract: The (spin projected) extended Hartree-Fock equations are derived and discussed in the general (“many λi”) case. The derivation is based on the corresponding generalized Brillouin theorem, substituting in its expression the spin projected DODS Slater determinant as a linear combination of determinants. The expressions obtained for the elements of the different matrices ecd (c = a or b, and d = a or b) occurring in the equations are analyzed. The transformation of the equations into the form of a pseudoeigenvalue problem and the LCAO form of the equations are given, too. Finally the relation to the Goddard's GF equations is discussed in detail.
TL;DR: In this article, a Bethe-Salpeter equation for the amplitudes of the Dirac quark fields with heavy spin 12 quarks is discussed for the mesons.
TL;DR: In this paper, an investigation of density-dependent interactions, such as those of Vautherin and Brink, and Moszkowski and Ehlers, is carried out.
TL;DR: In this article, a simple technique is decribed for extracting from two-body effective interaction matrix elements the separate contributions of the parts of the effective interaction of tensor rank zero, one and two in spin space.
TL;DR: The theory of the magnetic excitations at low temperatures has been developed with the aid of the pseudo-boson technique in terms of the crystal field and spin-orbit parameters of the individual ions and of the exchange interactions between neighbouring ions.
Abstract: The magnetic excitations of cobalt fluoride have been studied both theoretically and experimentally. The theory of the magnetic excitations at low temperatures has been developed with the aid of the pseudo-boson technique in terms of the crystal field and spin-orbit parameters of the individual ions and of the exchange interactions between neighbouring ions. The model with surprisingly simple forms of exchange interaction gives a very good description of many of the experimental results. Measurements of the longitudinal spin correlations near the Neel temperature have been made with slow neutron inelastic scattering techniques. The results show that the longitudinal spin correlations have a small frequency width; the width at half maximum of the quasi-elastic peak is, at all temperatures and wavevectors, less than 0.12 THz.
TL;DR: In this paper, the authors derived explicit expressions for the free energy per spin, the z component of the magnetization per spin in the finite a-cyclic XY model for the thermodynamic limit.
TL;DR: In this article, it was shown that the equation of motion for spin-1 particles with an anomalous magnetic moment in a homogeneous magnetic field can be diagonalized by applying the Foldy-Wouthuysen transformation.
Abstract: We find that the equation of motion for spin-$\frac{1}{2}$ and spin-1 particles with an anomalous magnetic moment in a homogeneous magnetic field can be diagonalized by applying the Foldy-Wouthuysen transformation. The energy eigenvalues are then easily obtained by observation.
TL;DR: In this paper, the spin-hamiltonian parameters for Mn2+ in K2MgF4, K2ZnF4 and Rb2CdF4 have been determined by means of ENDOR experiments at 4.2K.
TL;DR: The 1960 version of the Nuclear DAta Sheets for A = 94 has bee revised on the basis of experimental data received prior to April 1, 1973 as mentioned in this paper, and information from approximately 165 papers and communications has been included in the present evaluation.
TL;DR: In this article, a detailed discussion of the generalized susceptibilities and spectral functions rho alpha beta of the Ising model in a transverse field Gamma is provided, and the leading contributions to the damping of the excitations as well as the first-order shift in their energy and in the critical temperature are obtained.
Abstract: For Pt. I see ibid., vol. 6, no. 15, 2459 (1973). By taking the (1/z) expansion one order beyond that considered in Pt. I, a detailed discussion is provided of the generalized susceptibilities and spectral functions rho alpha beta of the Ising model in a transverse field Gamma . The leading contributions to the damping of the excitations as well as the first-order shift in their energy and in the critical temperature, are obtained. The damping arises from break-up into (i) a spin wave and a spin fluctuation or (ii) a pair of spin waves.
TL;DR: In this article, the sum rules form a set of 8 equations connecting 16 partial sums of spectroscopic factors for stripping and pick-up to states of different spin, and fits to experimental data enable further spin assignments to be made to states in 44 Sc and 46 Sc.
TL;DR: In this paper, it was shown that the free energy of a system of n-dimensional spins with Kac type potential is equal to the Curie-Weiss system in which every spin interacts equally with every other spin.
Abstract: It is proved that the free energy of a system ofn-dimensional spins with Kac type potential is equal, in the infinite range zero strength limit, to the free energy of the corresponding Curie-Weiss system in which every spin interacts equally with every other spin.