TY - JOUR

T1 - Quantum energy density

T2 - Improved efficiency for quantum Monte Carlo calculations

AU - Krogel, Jaron T.

AU - Yu, Min

AU - Kim, Jeongnim

AU - Ceperley, David M.

PY - 2013/7/29

Y1 - 2013/7/29

N2 - We establish a physically meaningful representation of a quantum energy density for use in quantum Monte Carlo calculations. The energy density operator, defined in terms of Hamiltonian components and density operators, returns the correct Hamiltonian when integrated over a volume containing a cluster of particles. This property is demonstrated for a helium-neon "gas," showing that atomic energies obtained from the energy density correspond to eigenvalues of isolated systems. The formation energies of defects or interfaces are typically calculated as total-energy differences. Using a model of δ-doped silicon (where dopant atoms form a thin plane) we show how interfacial energies can be calculated more efficiently with the energy density, since the region of interest is small. We also demonstrate how the energy density correctly transitions to the bulk limit away from the interface where the correct energy is obtainable from a separate total-energy calculation.

AB - We establish a physically meaningful representation of a quantum energy density for use in quantum Monte Carlo calculations. The energy density operator, defined in terms of Hamiltonian components and density operators, returns the correct Hamiltonian when integrated over a volume containing a cluster of particles. This property is demonstrated for a helium-neon "gas," showing that atomic energies obtained from the energy density correspond to eigenvalues of isolated systems. The formation energies of defects or interfaces are typically calculated as total-energy differences. Using a model of δ-doped silicon (where dopant atoms form a thin plane) we show how interfacial energies can be calculated more efficiently with the energy density, since the region of interest is small. We also demonstrate how the energy density correctly transitions to the bulk limit away from the interface where the correct energy is obtainable from a separate total-energy calculation.

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U2 - 10.1103/PhysRevB.88.035137

DO - 10.1103/PhysRevB.88.035137

M3 - Article

AN - SCOPUS:84881174804

VL - 88

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 0163-1829

IS - 3

M1 - 035137

ER -