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Showing 1 to 20 of 44 for “"qmc"”.
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Establishing framework of quantum Monte Carlo calculation on II-V semiconductor
… Therefore, we introduces quantum Monte Carlo (QMC) method, which is an exciting technique with benchmark quality results. Instead of the mean- field interaction, QMC use stochastic approaches to solve the real Schr ̈odinger equation, which includes the many body interaction of electrons …
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Quantum Monte Carlo With a *Stochastic Poisson Solver
"Quantum Monte Carlo (QMC) is an extremely powerful method to treat many-body systems. Usually QMC has been applied in cases where the interaction potential has a simple analytic form, like the 1/r Coulomb potential. However, in a complicated environment as in a semiconductor heterostructure, the …
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Quantum monte carlo with a stochastic potential solver
"Quantum Monte Carlo (QMC) is an extremely powerful method to treat many-body systems. Usually QMC has been applied in cases where the interaction potential has a simple analytic form, like the 1=r Coulomb potential. However, in a complicated environment as in a semiconductor heterostructure, the …
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Accurate Treatments of Electronic Correlation: Phase Transitions in an Idealized One-Dimensional Ferroelectric and Modelling Experimental Quantum Dots
… quasi-2D structures, are analyzed. In the first QMC is contrasted with a large set of commonly used electronic structure methods including MSFT, KLI, LSDA, and CCSD, and in the second we scrutinize whether SDW states truly exist as predicted by LSDA. In conjunction with the Computational …
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Application of quantum Monte Carlo methods to molecular potential energy surfaces
… technique called quantum Monte Carlo (QMC). QMC methods scale with the number of electrons as n<sup>3</sup> and have been found to scale almost linearly with the number of processors, even beyond 500,000 cores. However, despite the favorable scaling towards large systems, the cost of …
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Accurate Treatments of Electronic Correlation: Phase Transitions in an Idealized 1D Ferroelectric and Modelling Experimental Quantum Dots
"Quantum Monte Carlo (QMC) is one of the most powerful methods for solving many body problems in Physics and Chemistry. MC sampling allows one to measure physical properties systems with very complicated wave functions that incorporate correlation between the electrons. Additionally, QMC has O(N3) …
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Quantum Monte Carlo for accurate energies and materials design
Quantum Monte Carlo (QMC) is an electronic structure calculation method that is capable of calculating incredibly accurate solutions of Schrödinger equation of quantum mechanics for real systems. However, QMC is computationally very expensive compared to density functional theory (DFT) method, such …
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Study of Ultracold Fermi Gases in the BCS-BEC Crossover: Quantum Monte Carlo Methods, Hydrodynamics and Local Density Approximation.
… in some regimes. However Quantum Monte Carlo (QMC) techniques provide more accurate results especially in the strongly interacting regimes. For confined systems it is possible to use QMC only for a few particles, so that, for large number of particles, a fruitful combined use of Density …
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Quantum Monte Carlo Study of Hydrogen Adsorption on Carbon and Transition Metal Systems
… thesis research has successfully carried out a QMC study of hydrogen adsorption on Ti-ethylene molecular systems demonstrating reversible hydrogen adsorption on molecular TiH$_2$C$_2$H$_4$. This system is chosen as representative of larger carbon-transition-metal systems that may be relevant for …
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Understanding and extending the role of first-principles quantum Monte Carlo
… trial wavefunctions in quantum Monte Carlo (QMC) calculations. Trial wavefunction quality is one of the key limiting factors to the accuracy of QMC, and in this study I demonstrate one way to systematically overcome this barrier. I also present a study comparing the energetic accuracy of QMC …
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Quantum Monte Carlo methods for molecular systems: New developments and applications
… the applicability of the quantum Monte Carlo (QMC) methods to larger molecular systems and check the reliability of traditional approaches, (ii) determine the impact of correlation energy on a variety of systems in which correlation is important, (iii) investigate new silicon clusters which may …
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Quantum Monte Carlo methods for molecular systems: New developments and applications
… the applicability of the quantum Monte Carlo (QMC) methods to larger molecular systems and check the reliability of traditional approaches, (ii) determine the impact of correlation energy on a variety of systems in which correlation is important, (iii) investigate new silicon clusters which may …
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High-accuracy electronic structure quantum Monte Carlo for molecular systems
Quantum Monte Carlo (QMC) is one of the most promising methods for solving quantum many-body problems. QMC combines known analytical properties of wave functions, results from other methods, and stochastic techniques, into a powerful tool for investigation of the electronic structure of real …
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Monte Carlo methods: application to hydrogen gas and hard spheres
Quantum Monte Carlo (QMC) methods are among the most accurate for computing ground state properties of quantum systems. The two major types of QMC we use are Variational Monte Carlo (VMC), which evaluates integrals arising from the variational principle, and Diffusion Monte Carlo (DMC), which …
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Application of quantum Monte Carlo methods to excitonic and electronic systems
… and development of quantum Monte Carlo (QMC) methods. We begin by proposing a technique to maximise the efficiency of the extrapolation of DMC results to zero time step, finding that a relative time step ratio of 1:4 is optimal. We discuss the post-processing of QMC data and the …
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Quantum Monte Carlo study of correlated electronic systems
… Instead of making approximations to Hamiltonian, QMC methods work with the wave functions, and the computational cost scales well with the system size. With the development of parallel computing, QMC calculations on large systems are becoming more and more feasible. We have investigated two …
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Quantum Monte Carlo simulations of electrons and holes
… of electrons and holes with quantum Monte Carlo (QMC) techniques, covering three related areas: (1) elastic scattering of excitons, (2) thermodynamics of electron-hole plasmas, and (3) electrons confined in a quantum dot. Excitons are bound states of an electron and a hole, and obey Bose …
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Ab initio investigations of low Z materials under extreme conditions
… is suitable not only for direct applications of QMC to problems of interest, but also to benchmark and establish confidence in widely used density functional theory (DFT) calculations. The purpose of my thesis will be two-fold: to use ab initio methods like quantum Monte Carlo to shed light on …
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Quasi-Monte Carlo and Picard Iteration Algorithms for the Nonlinear Hydrodynamics, Dynamics and Controls of Wave Energy Converters
… The proposed framework debuts Quasi-Monte Carlo (QMC) spatial integration in nonlinear wave-body interactions, in conjunction with a new extension of Modified Chebyshev Picard Iteration compatible with the fluid force impulses. A mesh-free geometric representation using signed distance functions …
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First principles quantum Monte Carlo study of correlated electronic systems
… we apply first principles quantum Monte Carlo (QMC) method to several representative systems to study the electron correlations in transition metal oxides (vanadium dioxide) and low dimensional electronic systems (graphene and graphene-like two dimensional systems). Vanadium dioxide (VO2) is a …
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