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: Only one independent parameter, r s, the “typical” distance between electrons. ζ is the spin polarization.

Pair Correlation Function

Momentum Density Gori-Giorgi and Ziesche, PRB 66,

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

PCF Size Convergence

PCF with Backflow

Pair Correlation Function

On top pair density

DFT Finite Size Corrections

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

Results for PCF PCF (anti-parallel spins) VMC, 162 electrons, r s =3.0, ζ=0.0