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Title: Finite-temperature properties of strongly correlated systems via variational Monte Carlo

Authors:
;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1355960
Grant/Contract Number:
FG02-12ER46875
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 20; Related Information: CHORUS Timestamp: 2017-05-08 22:13:19; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Claes, Jahan, and Clark, Bryan K. Finite-temperature properties of strongly correlated systems via variational Monte Carlo. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.205109.
Claes, Jahan, & Clark, Bryan K. Finite-temperature properties of strongly correlated systems via variational Monte Carlo. United States. doi:10.1103/PhysRevB.95.205109.
Claes, Jahan, and Clark, Bryan K. Mon . "Finite-temperature properties of strongly correlated systems via variational Monte Carlo". United States. doi:10.1103/PhysRevB.95.205109.
@article{osti_1355960,
title = {Finite-temperature properties of strongly correlated systems via variational Monte Carlo},
author = {Claes, Jahan and Clark, Bryan K.},
abstractNote = {},
doi = {10.1103/PhysRevB.95.205109},
journal = {Physical Review B},
number = 20,
volume = 95,
place = {United States},
year = {Mon May 08 00:00:00 EDT 2017},
month = {Mon May 08 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevB.95.205109

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  • A new effective Monte Carlo algorithm based on principles of continuous time is presented. It allows calculating, in an arbitrary discrete basis, thermodynamic quantities and linear response of mixed boson-fermion, spin-boson, and other strongly correlated systems which admit no analytic description.
  • Using the Metropolis Monte Carlo integration technique, we calculate upper bounds to the correlation energy of a Be atom for a variety of wave functions. With this method, it is simple to treat unconventional wave functions, including those which depend on the interelectronic distance r/sub i/j. We obtain about 40% of the correlation energy by using only a simple two-parameter Jastrow function of r/sub i/j with a single Slater determinant of Hartree--Fock orbitals. A four configuration wave function with this Jastrow function yields 87% of the correlation energy. Several wave functions derived from nonvariational methods are shown to give nomore » correlation energy when used in a strictly variational computation.« less
  • Accurate numerical solution of the five-body Schroedinger equation is effected via variational Monte Carlo. The spectrum is assumed to exhibit a narrow resonance with strangeness S = +1. A fully antisymmetrized and pair-correlated five-quark wave function is obtained for the assumed non-relativistic Hamiltonian which has spin, isospin, and color dependent pair interactions and many-body confining terms which are fixed by the non-exotic spectra. Gauge field dynamics are modeled via flux tube exchange factors. The energy determined for the ground states with J{pi} (1/2){sup -}((1/2){sup +}) is 2.22 GeV (2.50 GeV). A lower energy negative parity state is consistent with recentmore » lattice results. The short-range structure of the state is analyzed via its diquark content.« less
  • We present a many-body diffusion quantum Monte Carlo (DMC) study of the bulk and defect properties of NiO. We find excellent agreement with experimental values, within 0.3%, 0.6%, and 3.5% for the lattice constant, cohesive energy, and bulk modulus, respectively. The quasiparticle bandgap was also computed, and the DMC result of 4.72 (0.17) eV compares well with the experimental value of 4.3 eV. Furthermore, DMC calculations of excited states at the L, Z, and the gamma point of the Brillouin zone reveal a flat upper valence band for NiO, in good agreement with Angle Resolved Photoemission Spectroscopy results. To studymore » defect properties, we evaluated the formation energies of the neutral and charged vacancies of oxygen and nickel in NiO. A formation energy of 7.2 (0.15) eV was found for the oxygen vacancy under oxygen rich conditions. For the Ni vacancy, we obtained a formation energy of 3.2 (0.15) eV under Ni rich conditions. These results confirm that NiO occurs as a p-type material with the dominant intrinsic vacancy defect being Ni vacancy.« less
  • We present a many-body diffusion quantum Monte Carlo (DMC) study of the bulk and defect properties of NiO. We find excellent agreement with experimental values, within 0.3%, 0.6%, and 3.5% for the lattice constant, cohesive energy, and bulk modulus, respectively. The quasiparticle bandgap was also computed, and the DMC result of 4.72 (0.17) eV compares well with the experimental value of 4.3 eV. Furthermore, DMC calculations of excited states at the L, Z, and the gamma point of the Brillouin zone reveal a flat upper valence band for NiO, in good agreement with Angle Resolved Photoemission Spectroscopy results. To studymore » defect properties, we evaluated the formation energies of the neutral and charged vacancies of oxygen and nickel in NiO. A formation energy of 7.2 (0.15) eV was found for the oxygen vacancy under oxygen rich conditions. For the Ni vacancy, we obtained a formation energy of 3.2 (0.15) eV under Ni rich conditions. Lastly, these results confirm that NiO occurs as a p-type material with the dominant intrinsic vacancy defect being Ni vacancy. (C) 2015 AIP Publishing LLC.« less