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Showing 1 to 20 of 26 for “"Path integral Monte Carlo"”.
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Path integral Monte Carlo and the electron gas
Path integral Monte Carlo is a proven method for accurately simulating quantum mechanical systems at finite-temperature. By stochastically sampling Feynman's path integral representation of the quantum many-body density matrix, path integral Monte Carlo includes non-perturbative effects like …
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Path integral Monte Carlo simulations of hot dense hydrogen
Submitted by William Weathers (weathrs2@illinois.edu) on 2012-05-29T19:07:56Z No. of bitstreams: 1 2000_militzer.pdf: 5843643 bytes, checksum: 9fb0d3463540b28660c4173dd81b5730 (MD5)
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Path integral Monte Carlo simulations and their relation to recent advances in nanophysics
… three parts. In part one an introduction to the path integral Monte Carlo method (PIMC) and an overview on the experimental techniques for making nanoscopic semiconductor structures are given. Part two consists of two already published articles on the application of PIMC to nanoscopic quantum …
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Path Integral Monte Carlo Simulations of Helium: From Superfluid Droplets to Quantum Crystals
Finally, we have calculated the Deybe-Waller factor in solid helium for a range of temperatures and densities, and compared the scaling behavior with the predictions of harmonic theory. The first non-Gaussian contribution to the density distribution was calculated.
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Path Integral Monte Carlo Simulations of Helium: From Superfluid Droplets to Quantum Crystals
… in microscopic, inhomogeneous helium systems. Path Integral Monte Carlo is a powerful method for calculating the equilibrium properties of quantum systems at finite temperature. We have achieved linear scaling of computer time with number of particles through the use of neighbor lists, allowing …
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Advancements in the Path Integral Monte Carlo Method for Many -Body Quantum Systems at Finite Temperature
After describing these advancements in methodology, we apply our new technology to fluid sodium near its liquid-vapor critical point. In particular, we explore the microscopic mechanisms which drive the continuous change from a dense metallic liquid to an expanded insulating vapor above the …
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Advancements in the Path Integral Monte Carlo Method for Many-Body Quantum Systems at Finite Temperature
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Path integral Monte Carlo simulations of solid H2 surfaces and thin 4He films on H2 substrates
… P. Feynman's formulation of quantum mechanics, Path Integral Monte Carlo is a computational ab-initio method to calculate finite temperature equilibrium properties of quantum many-body systems. As input, only fundamental physical constants and pair-potentials are required. We carry out the first …
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A continuum path integral approach to the simulation of a unitary gas
… i.e.the scattering length $a_{s}=-\infty$. A path integral Monte Carlo simulation of such a system is performed using an exact novel zero-range, delta function pair propagator which has been tuned to the unitary limit so that essentially all interactions amongst the interacting particles are …
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Statistical Analysis of Highly Correlated Systems in Biology and Physics
I have also used Path Integral Monte Carlo techniques to explore the limit of rapid rotations, where the Gross-Pitaevskii equation is no longer valid. Interestingly, the Gross-Pitaevskii equation seems to be valid for much higher densities than expected if properly renormalized. I show that, in …
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X-Ray Debye -Waller Factor Measurements of Helium Crystals
… agree well with computational values, made using path integral Monte Carlo methods. The Lindemann ratios were around 0.11 for both isotopes, with the 3He values being larger at similar densities. A 3He-4He mass-scaling factor of 4/3 for the equivalent Debye temperature for the measured …
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Novel Quantum Monte Carlo Approaches for Quantum Liquids
Quantum Monte Carlo methods are a powerful suite of techniques for solving the quantum many-body problem. By using random numbers to stochastically sample quantum properties, QMC methods are capable of studying low-temperature quantum systems well beyond the reach of conventional deterministic …
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Physics under extreme conditions: Magnetized atoms and hot dense plasmas
… random walks (correlation function quantum Monte Carlo). We present the first calculations for magnetized lithium and carbon for field strengths ${\le}10\sp{11}$G, and construct a very accurate spectrum for magnetized helium. For the electron gas, or one component plasma (OCP), we carefully …
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Pairing and entanglement: quantum Monte Carlo studies
… in this dissertation is the use of quantum Monte Carlo methods to study two ideas in quantum many-body problems: superfluidity and entanglement. Density matrices are presented a central tool in the analysis, as are discussed in the review of path integral Monte Carlo (PIMC) and variational …
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Quantum Monte Carlo studies of dense hydrogen and two-dimensional Bose liquids
Quantum Monte Carlo techniques; in their various incarnations, calculate ground state or finite temperature properties of many-body quantum systems. We apply the path-integral Monte Carlo method to hydrogen at densities and temperatures in the regime of cooperative thermal and pressure …
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Quantum Monte Carlo: Applications of the Twist -Averaged Boundary Conditions and the Calculation of Forces
Quantum Monte Carlo (QMC) method is a powerful simulation tool for studying the properties of physical and chemical systems. The application of QMC to extended systems subjects to finite size effects because the simulation is often done with a small system in a super cell geometry. Periodic …
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Quantum Monte Carlo: Applications of the Twist-averaged Boundary Conditions and the Calculation of Forces
Quantum Monte Carlo(QMC) method is a powerful simulation tool for studying the properties of physical and chemical systems. The application of QMC to extended systems subjects to finite size effects because the simulation is often done with a small system in a super cell geometry. Periodic boundary …
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Fluctuations and Instantons in Complex Landscapes: From Ligand Unbinding to Proton Transfer
… ab initio molecular dynamics (AIMD) and quantum Monte Carlo methods (QMC) for computational enzymology. An ideal system for the application of AIMD, are the cytochromes P450 (CYP450s). Most AIMD calculations are performed using plane-wave (PW) density functional theory as an electronic structure …
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Quantum Monte Carlo simulations of electrons and holes
… systems 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 …
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Topics in the Theory of Quantum Degenerate Gases
… potential by Janzen and Aziz and using the Path Integral Monte Carlo (PIMC) technique. We show that, for the calculation of the second coefficient, the method is successful whereas for the third the particular implementation that we chose (free particle sampling) is not sufficient to produce …
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