Simulation of quantum systems with random walks: A new algorithm for charged systems
Journal Article
·
· J. Comput. Phys.; (United States)
Random walks with branching have been used to calculate exact properties of the ground state of quantum many-body systems. In this paper, a more general Green's function identity is derived which relates the potential energy, a trial wavefunction, and a trial density matrix to the rules of a branched random walk. It is shown that an efficient algorithm requires a good trial wavefunction, a good trial density matrix, and a good sampling of this density matrix. An accurate density matrix is constructed for Coulomb systems using the path integral formula. The random walks from this new algorithm diffuse through phase space an order of magnitude faster than the previous Green's Function Monte Carlo method. In contrast to the simple diffusion Monte Carlo algorithm, it is exact method. Representative results are presented for several molecules.
- Research Organization:
- University of California, Lawrence Livermore National Laboratory, Livermore, California 94550
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5385609
- Journal Information:
- J. Comput. Phys.; (United States), Journal Name: J. Comput. Phys.; (United States) Vol. 51:3; ISSN JCTPA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
657002* -- Theoretical & Mathematical Physics-- Classical & Quantum Mechanics
657006 -- Theoretical Physics-- Statistical Physics & Thermodynamics-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALGORITHMS
ALKALI METAL COMPOUNDS
ALKALI METALS
CHARGED-PARTICLE TRANSPORT
DENSITY MATRIX
ELEMENTS
ENERGY
ENERGY LEVELS
FEYNMAN PATH INTEGRAL
FLUIDS
FUNCTIONS
GASES
GREEN FUNCTION
GROUND STATES
HELIUM
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
INTEGRALS
LITHIUM
LITHIUM COMPOUNDS
LITHIUM HYDRIDES
MANY-BODY PROBLEM
MATHEMATICAL LOGIC
MATHEMATICAL SPACE
MATRICES
MECHANICS
METALS
MONTE CARLO METHOD
NONMETALS
PHASE SPACE
POTENTIAL ENERGY
QUANTUM MECHANICS
RADIATION TRANSPORT
RANDOMNESS
RARE GASES
SPACE
STOCHASTIC PROCESSES
WAVE FUNCTIONS
657006 -- Theoretical Physics-- Statistical Physics & Thermodynamics-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALGORITHMS
ALKALI METAL COMPOUNDS
ALKALI METALS
CHARGED-PARTICLE TRANSPORT
DENSITY MATRIX
ELEMENTS
ENERGY
ENERGY LEVELS
FEYNMAN PATH INTEGRAL
FLUIDS
FUNCTIONS
GASES
GREEN FUNCTION
GROUND STATES
HELIUM
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
INTEGRALS
LITHIUM
LITHIUM COMPOUNDS
LITHIUM HYDRIDES
MANY-BODY PROBLEM
MATHEMATICAL LOGIC
MATHEMATICAL SPACE
MATRICES
MECHANICS
METALS
MONTE CARLO METHOD
NONMETALS
PHASE SPACE
POTENTIAL ENERGY
QUANTUM MECHANICS
RADIATION TRANSPORT
RANDOMNESS
RARE GASES
SPACE
STOCHASTIC PROCESSES
WAVE FUNCTIONS