3,316,906 research outputs found

    T>0 ensemble state density functional theory revisited

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    A logical foundation of equilibrium state density functional theory in a Kohn-Sham type formulation is presented on the basis of Mermin's treatment of the grand canonical state. it is simpler and more satisfactory compared to the usual derivation of ground state theory, and free of remaining open points of the latter. It may in particular be relevant with respect to cases of spontaneous symmetry breaking like non-collinear magnetism and orbital order.Comment: 7 pages, no figure

    Ground-State Quantum-Electrodynamical Density-Functional Theory

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    In this work we establish a density-functional reformulation of coupled matter-photon problems subject to general external electromagnetic fields and charge currents. We first show that for static minimally-coupled matter-photon systems an external electromagnetic field is equivalent to an external charge current. We employ this to show that scalar external potentials and transversal external charge currents are in a one-to-one correspondence to the expectation values of the charge density and the vector-potential of the correlated matter-photon ground state. This allows to establish a Maxwell-Kohn-Sham approach, where in conjunction with the usual single-particle Kohn-Sham equations a classical Maxwell equation has to be solved. In the magnetic mean-field limit this reduces to a current-density-functional theory that does not suffer from non-uniqueness problems and if furthermore the magnetic field is zero recovers standard density-functional theory

    Ground-state Wigner functional of linearized gravitational field

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    The deformation quantization formalism is applied to the linearized gravitational field. Standard aspects of this formalism are worked out before the ground state Wigner functional is obtained. Finally, the propagator for the graviton is also discussed within the context of this formalism.Comment: 18 pages, no figure

    Functional genre in Illinois State Government digital documents

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    Provisions for collecting or archiving digital documents can be informed by knowledge of the genres of documents likely to be encountered. Although different aspects of collecting and curation may classify documents into genres based on differing criteria (e.g., size, file format, subject), this document addresses classification based on the functional role the document plays in state government, akin to (Toms, 2001), but here specifically Illinois State Government (ISG). The classifications listed herein are based on an overview of ISG digital documents, encountered in over nine years of gathering and archiving work with and for the Illinois State Library (ISL), and on discussions with practitioners in cataloging and in government documents librarianship. This report states definitions, and including examples of each such genre. State government documents are interesting in this regard in that they are presumably somewhat comparable to both federal government documents and business documents. Perhaps surprisingly, there are also portions of the State Web that are somewhat less than businesslike, either in tone or in technological proficiency of implementation. In this respect state government digital documents may also be useful approximations to documents produced either personally or by small activities. Having a list of government document genres can inform work in information promulgation (e.g., through website design, or the design of a series of printed materials), and the grouping of documents for digital library or archival purposes.Library of Congress / NDIIPP-2 A6075unpublishednot peer reviewe

    Transverse spin gradient functional for non-collinear spin density functional theory

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    We present a novel functional for spin density functional theory aiming at the description of non-collinear magnetic structures. The construction of the functional employs the spin-spiral-wave state of the uniform electron gas as reference system. We show that the functional depends on transverse gradients of the spin magnetization, i.e., in contrast to the widely used local spin density approximation, the functional is sensitive to local changes of the direction of the spin magnetization. As a consequence the exchange-correlation magnetic field is not parallel to the spin magnetization and a local spin-torque is present in the ground state of the Kohn-Sham system. As a proof-of-principle we apply the functional to a Chromium mono-layer in the non-collinear 120{120^{\circ}}-N{\'e}el state.Comment: Paper: 4 pages, 3 figures, Supplemental Material: 2 page
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