Results 351 to 360 of about 13,167,523 (376)

Density matrix formulation for quantum renormalization groups.

Physical Review Letters, 1992
A generalization of the numerical renormalization-group procedure used first by Wilson for the Kondo problem is presented. It is shown that this formulation is optimal in a certain sense.
S. White
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Density matrices from densities

Chemical Physics Letters, 1990
Abstract The density matrix can be reconstructed from the density alone, if a basis set is used whose product functions are all linearly independent. This is not the case for quantum-chemical basis sets, except for small s-type sets. In case of the idempotency constraint on the density matrix - justified in the density functional approach, but in ...
W. H. E. Schwarz, B. Müller
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Density and Density Matrices in Density Functional Theory

1990
Publisher Summary This chapter discusses density and density matrices in density functional theory. It also discusses particle number and order; fundamental Hilbert spaces; matrices and restricted operators; local and nonlocal operators; equidensity orbitals and n representability; and negative consequences of a finite model.
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The capacity of low-density parity-check codes under message-passing decoding

IEEE Transactions on Information Theory, 2001
We present a general method for determining the capacity of low-density parity-check (LDPC) codes under message-passing decoding when used over any binary-input memoryless channel with discrete or continuous output alphabets.
T. Richardson, R. Urbanke
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Correction of flux measurements for density effects due to heat and water vapour transfer

, 1980
When the atmospheric turbulent flux of a minor constituent such as CO2 (or of water vapour as a special case) is measured by either the eddy covariance or the mean gradient technique, account may need to be taken of variations of the constituent's ...
E. K. Webb, G. Pearman, R. Leuning
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The density in density functional theory

Journal of Molecular Structure: THEOCHEM, 2010
Abstract The paper begins with the definition of the electron density given by Schrodinger in 1926 and traces its use and many applications directed at the understanding of the properties of matter to its present day role in density functional theory and the development of the quantum mechanics of an open system.
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Density functions and density functionals

Philosophical Magazine B, 1994
Abstract This paper is concerned with the electron density and other ‘property densities’ and, through the use of concrete examples, touches upon some of the fundamental aspects of density functional theory (DFT) that are seldom considered. In particular, this paper considers what density functions are needed in discussing observable electronic ...
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Density Matrices and Density Operators

1996
As was repeatedly seen in the last chapter, for computing most of the usual matrix elements only a few of the many coordinates of an N-particle wavefunction are used, where due to the symmetry properties it is irrelevant which ones. Density matrices are a tool to extract the relevant information out of such monstrous constructs as are N-particle ...
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Semiempirical GGA‐type density functional constructed with a long‐range dispersion correction

Journal of Computational Chemistry, 2006
S. Grimme
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Density Operator, Density Matrix

2011
The density matrix is especially suited for a description of an arbitrary (pure or mixed) polarization state (differently from a wave function). With it averages and expectation values as well as statistical distributions of measurable quantities can be described.
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