A QMC Study of the Homogeneous Electron Gas

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. ? 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
• _at_rs0.5 increases VMC correlation energy
  by 5
• Three-body Jastrow terms
• Holtzmann et al., Phys. Rev. E 68
  046707
• _at_ rs20, 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
(No Transcript)
9
(No Transcript)
10
Pair Correlation Function
11
On top pair density
12
DFT Finite Size Corrections
13
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

14
Results for PCF
VMC, 162 electrons, rs3.0, ?0.0
PCF (anti-parallel spins)