Spin-dependent Hedin's equations

Hedin's equations for the electron self-energy and the vertex were originally derived for a many-electron system with Coulomb interaction. In recent years it has been increasingly recognized that spin interactions can play a major role in determining physical properties of systems such as nanoscale magnets or of interfaces and surfaces. We derive a generalized set of Hedin's equations for quantum many-body systems containing spin interactions, e.g. spin-orbit and spin-spin interactions. The corresponding spin-dependent GW approximation is constructed.Comment: 5 pages, 1 figur

The Quicksands of Originalism: Interpreting Minnesota’s Constitutional Past

There are several varieties of the “originalist” school of constitutional thought, but all subscribe in one degree or another to the belief that a constitutional clause should be interpreted according to its original meaning or the original intent of its authors. That original understanding or intent can be discerned from the text of the clause, the history of its drafting and ratification and, sometimes, early practices and court decisions interpreting that clause. It rightly has been called a “grand theory” because it is simple and clear, explains so much, and it has the almost irresistible attraction of being anchored firmly in history, a past illuminated by the writings and speeches of heroic figures -- the “founding fathers.” Like frontier settlers in the novels of O. E. Rölvaag, lawyers, legal scholars and jurists who attempt to interpret Minnesota\u27s Constitution on the basis of its original understanding or the framers\u27 intent encounter unexpected hardships, hazards, and deprivations. This article explores practical reasons why a strict originalist interpretation of the Minnesota Constitution has never taken hold, and probably never will. It does not address the worthiness of the originalist school of adjudication at all. It is both provoked and inspired by an essay published in these pages a year ago by Professor Russell Pannier on the decision of the Minnesota Supreme Court in the case of Abraham v. Hennepin County. There, the court held that an employee claiming retaliatory discharge under the state “whistleblower act” had a right to a jury trial under Article 1, section 4 of the Minnesota Constitution. Professor Pannier concluded that the Abraham court attempted to ride “originalist” and “non-originalist” horses in the same race; not mincing words, he found the court\u27s reasoning “incoherent” and “internally inconsistent.” But there is another view of Abraham, that with it, the court boldly built a contemporary structure for the analysis of the jury right that is faithful to the democratic order and harmonious with this state\u27s constitutional past

The Quicksands of Originalism: Interpreting Minnesota’s Constitutional Past

There are several varieties of the “originalist” school of constitutional thought, but all subscribe in one degree or another to the belief that a constitutional clause should be interpreted according to its original meaning or the original intent of its authors. That original understanding or intent can be discerned from the text of the clause, the history of its drafting and ratification and, sometimes, early practices and court decisions interpreting that clause. It rightly has been called a “grand theory” because it is simple and clear, explains so much, and it has the almost irresistible attraction of being anchored firmly in history, a past illuminated by the writings and speeches of heroic figures -- the “founding fathers.” Like frontier settlers in the novels of O. E. Rölvaag, lawyers, legal scholars and jurists who attempt to interpret Minnesota\u27s Constitution on the basis of its original understanding or the framers\u27 intent encounter unexpected hardships, hazards, and deprivations. This article explores practical reasons why a strict originalist interpretation of the Minnesota Constitution has never taken hold, and probably never will. It does not address the worthiness of the originalist school of adjudication at all. It is both provoked and inspired by an essay published in these pages a year ago by Professor Russell Pannier on the decision of the Minnesota Supreme Court in the case of Abraham v. Hennepin County. There, the court held that an employee claiming retaliatory discharge under the state “whistleblower act” had a right to a jury trial under Article 1, section 4 of the Minnesota Constitution. Professor Pannier concluded that the Abraham court attempted to ride “originalist” and “non-originalist” horses in the same race; not mincing words, he found the court\u27s reasoning “incoherent” and “internally inconsistent.” But there is another view of Abraham, that with it, the court boldly built a contemporary structure for the analysis of the jury right that is faithful to the democratic order and harmonious with this state\u27s constitutional past

Empirical modeling of the thermosphere: An overview

A summary is given of thermospheric density modeling history and standard atmospheres. In particular, the approaches of the Jacchia and MSIS models were compared and contrasted. It was concluded that the Jacchia models are best if drag is the primary concern. MSIS is superior for variations in composition and temperature variations and comparison with theoretical models is facilitated by the use of spherical harmonics, which also provide a simple and consistent way of obtaining simplifications. Advantages and disadvantages of both models are listed and discussed

Lifetime reduction of surface states at Cu, Ag and Au(111) caused by impurity scattering

We present density-functional results on the lifetime of the (111) surface state of the noble metals. We consider scattering on the Fermi surface caused by impurity atoms belonging to the 3d and 4sp series. The results are analyzed with respect to film thickness and with respect to separation of scattering into bulk or into surface states. While for impurities in the surface layer the overall trends are similar to the long-known bulk-state scattering, for adatom-induced scattering we find a surprising behavior with respect to the adatom atomic number. A plateau emerges in the scattering rate of the 3d adatoms, instead of a peak characteristic of the d resonance. Additionally, the scattering rate of 4sp adatoms changes in a zig-zag pattern, contrary to a smooth parabolic increase following Linde's rule that is observed in bulk. We interpret these results in terms of the weaker charge-screening and of interference effects induced by the lowering of symmetry at the surface

Frequency-dependent local interactions and low-energy effective models from electronic structure calculations

We propose a systematic procedure for constructing effective models of strongly correlated materials. The parameters, in particular the on-site screened Coulomb interaction U, are calculated from first principles, using the GW approximation. We derive an expression for the frequency-dependent U and show that its high frequency part has significant influence on the spectral functions. We propose a scheme for taking into account the energy dependence of U, so that a model with an energy-independent local interaction can still be used for low-energy properties.Comment: 16 pages, 5 figure

The quasiparticle spectral function in doped graphene

We calculate the real and imaginary electron self-energy as well as the quasiparticle spectral function in doped graphene taking into account electron-electron interaction in the leading order dynamically screened Coulomb coupling. Our theory provides the basis for calculating {\it all} one-electron properties of extrinsic graphene. Comparison with existing ARPES measurements shows broad qualitative agreement between theory and experiment. We also calculate the renormalized graphene momentum distribution function, finding a typical Fermi liquid discontinuity at k_F. We also provide a critical discussion of the relevant many body approximations (e.g. RPA) for graphene.Comment: 5 pages, 3 figure

Electron self-energy in A3C60 (A=K, Rb): Effects of t1u plasmon in GW approximation

The electron self-energy of the t1u states in A3C60 (A=K, Rb) is calculated using the so-called GW approximation. The calculation is performed within a model which considers the t1u charge carrier plasmon at 0.5 eV and takes into account scattering of the electrons within the t1u band. A moderate reduction (35 %) of the t1u band width is obtained.Comment: 4 pages, revtex, 1 figure more information at http://www.mpi-stuttgart.mpg.de/dokumente/andersen/fullerene