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Showing 1 to 20 of 27 for “"local density approximation"”.
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Study of Ultracold Fermi Gases in the BCS-BEC Crossover: Quantum Monte Carlo Methods, Hydrodynamics and Local Density Approximation.
… number of particles, a fruitful combined use of Density Functional Theory (DFT) and QMC is necessary. The study of the dynamics of ultracold gases has received little attention with QMC techniques, due to the intrinsic computational difficulty of the many-body problem, so that general …
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Theory of density functionals
<p>Density functional theory is an alternative quantum mechanical theory that offers simple ways of performing calculations of the electronic properties of matter. Many different methods derive from density functional theory. The most appealing for its simplicity and rigor is the theory of Kohn and …
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The development of a local orbital method and its applications to aluminum and platinum clusters
… based on the ab initio Harris functional of the local density approximation of density functional theory, by adding d orbitals into the original local orbital basis set of $sp\sp3$ orbitals. This enables the treatment of most elements in the periodic table including all $sp\sp3$ bonding elements …
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Temperature dependent structural, electronic and optical properties of the Si(100) surface from first principles
… results presented here were obtained using the local density approximation (LDA) to density functional theory (DFT), within the pseudo-potentials scheme. We present the results of the numerical simulations for the Si bulk and Si(100) surface; ab-initio molecular dynamics (AIMD) using the …
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Ab initio Beschreibung der elektronischen Struktur und der Transporteigenschaften von metallischen Nanodrähten
… are presented. The calculations are based on density functional theory in local density approximation using a Screened Korringa-Kohn-Rostoker-Green's function method. The method was extended for the description of quasi-onedimensional systems. Translational invariance in direction of the wire …
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Computer Modeling of Silicon Quantum Dot Floating -Gate Flash Memory Devices
… (3-D) Poisson and Kohn-Sham equations within the density functional formalism, where the quantum many-body interactions are treated according to the local-density approximation. We investigate the quantum-dot electronic structure, device capacitance-voltage characteristics and derive the threshold …
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Computational modelling of the electronic and structural properties of chalcopyrite-type semiconductors and platinum group metal chalcogenides
… gaps. Electronic structure calculations based on Density Functional Theory (DFT) have been extensively used to study and to describe such properties of many condensed matter systems. In this work, we have utilized DFT to study the electronic properties of eight chalcopyrite-type semiconductors …
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Besetzte und unbesetzte elektronische Struktur von geordneten Dünnschichtverbindungen der Seltenen Erden Eu und Yb mit den Übergangsmetallen Pd und Ni
… structure is in good accordance with results of local-density-approximation band-structure calculations.
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Quasi-condensation in low-dimensional Bose gases
… is possible, which exhibits suppressed density fluctuations, but whose phase fluctuates strongly. It is shown that modified mean-field theories based on a symmetry-breaking approach can even characterise phase coherence properties of such a quasi-condensate properly. A correct …
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Spin waves in doped graphene
… waves are described using time-dependent spin-density-functional response theory, treating dynamical xc effects within the Slater and Singwi-Tosi-Land-Sjolander approximations. We obtain spin-wave dispersions and spin stiffnesses as a function of doping and spin polarization, and discuss …
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Tunneling spectroscopy of highly ordered organic thin films
… of the Landauer transport formalism with a density-functional-parametrized tight-binding scheme within the Local Density Approximation (LDA) as well as semiempirical quantum chemistry calculations.
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MICROSCOPIC THEORY OF INFINITE NUCLEAR MATTER AND NON-EMPIRICAL ENERGY FUNCTIONALS
Nuclear density functional theory (DFT) and ab initio theory are complementary approaches to nuclear structure. DFT can be applied to the whole nuclear chart, but relies on empirical energy density functionals (EDFs). As a consequence, predictions in regions where experimental data are lacking, …
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Quantum Monte Carlo: Applications of the Twist -Averaged Boundary Conditions and the Calculation of Forces
… Lande g factor. At the experimental equilibrium density of liquid 3He, we computed the spin polarization energy and found the unpolarized state is stable, in agreement with experiments. We also studied the electronic energy in a slab geometry using both density functional theory within the local …
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Fission dynamics in a microscopic theory
… with the application of the time-dependent density functional theory (TDDFT) to investigate the fission dynamics of atomic nucleus, which is still one of the most complicated problem in nuclear physics and a full microscopic interpretation is still missing. The establishment of the …
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Mean-field theory for the dynamics of superfluid fermions in the BCS-BEC crossover
… Bogoliubov-de Gennes theory and also Superfluid Local Density Approximation. We have derived the expression of the linear response function and the dynamic structure factor in the random phase approximation. At zero temperature, the SLDA+RPA formalism indeed provides a better accuracy at low …
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Quantum Monte Carlo: Applications of the Twist-averaged Boundary Conditions and the Calculation of Forces
… Lande g factor. At the experimental equilibrium density of liquid 3He, we computed the spin polarization energy and found the unpolarized state is stable, in agreement with experiments. We also studied the electronic energy in a slab geometry using both density functional theory within the local …
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First principles investigation of the thermodynamic and kinetic properties of lithium transition metal oxides
… properties of Lix CoO2, we have used density functional theory within the local density approximation (LDA) along with the cluster expansion formalism. We have also developed a scheme to calculate from first principles, the diffusion coefficient in systems with significant …
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Fermi Mixtures: Effects of Engineered Confinements
… calculate experimental observables such as the density profiles and the angular momenta. From the study of Bose-Einstein condensates it is well known that an adiabatic rotation induces a quadrupole deformation of the trapped atomic cloud when the rotation exceeds a certain angular velocity. In …
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Spin-gap materials from first principles: properties and applications of half-metallic ferromagnets
… on NiMnSb. The investigations arebased on the Density Functional Theory (DFT), the most successful ab-initio theory for real solid state materials. We investigate the bulk properties, the properties of selected low index surfaces and for the case of NiMnSb/InP also a junction with a …
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Properties of dirty bosons in disordered optical lattices
… by studying trap-free situations. Constant density calculations show that, although the qualitative features of the phase diagram remain robust between speckle disorder and uniform box disorder, there are quantitative differences. Studies of the Bose-glass phase ex- plicitly show that it is …
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