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A QMC Study of the Homogeneous Electron Gas

A QMC Study of the Homogeneous Electron Gas. Graham Spink and Richard Needs, TCM, University of Cambridge. Homogeneous Electron Gas. Electrons move in uniform, positive background potential: Used in Local Density Approximation in DFT:

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A QMC Study of the Homogeneous Electron Gas

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  1. A QMC Study of the Homogeneous Electron Gas Graham Spink and Richard Needs, TCM, University of Cambridge

  2. Homogeneous Electron Gas • Electrons move in uniform, positive background potential: • Used in Local Density Approximation in DFT: • Only one independent parameter, rs, the “typical” distance between electrons. ζ is the spin polarization.

  3. Pair Correlation Function

  4. Momentum Density Gori-Giorgi and Ziesche, PRB 66, 235116

  5. “New” Techniques • More accurate Jastrow factor • Backflow López Ríos et al., submitted to Phys. Rev. E; @rs=0.5 increases VMC correlation energy by 5% • Three-body Jastrow terms Holtzmann et al., Phys. Rev. E 68 046707; @ rs=20, increases VMC correlation energy by over 1% • Different treatment of finite-size effects Drummond et al.,

  6. PCF Size Convergence

  7. PCF with Backflow

  8. Pair Correlation Function

  9. On top pair density

  10. DFT Finite Size Corrections

  11. Conclusions and Future Work • New techniques in QMC simulations make significant difference to quantities considered • With new data we can test recently proposed fitting procedures • Now continuing the above at intermediate densities and with DMC

  12. Results for PCF VMC, 162 electrons, rs=3.0, ζ=0.0 PCF (anti-parallel spins)

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