qmcpack/manual/spo_heg.tex

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\subsection{Homogeneous electron gas}
\label{sec:hegbasis}
The interacting Fermi Liquid has its own special determinantset for filling up a
Fermi surface. The shell number can be specified separately for both spin up and spin down.
This determines how many electrons to include of each time, only closed shells are currently
implemented. The shells are filled according to the rules of a square box, if other lattice
vectors are used, the electrons may not fill up a complete shell.
This following example can also be used for Helium simulations too, by specifying the
proper pair interaction in the Hamiltonian section.
\begin{lstlisting}[caption=2D Fermi Liquid example: particle specification ]
<qmcsystem>
<simulationcell name="global">
<parameter name="rs" pol="0" condition="74">6.5</parameter>
<parameter name="bconds">p p p</parameter>
<parameter name="LR_dim_cutoff">15</parameter>
</simulationcell>
<particleset name="e" random="yes">
<group name="u" size="37">
<parameter name="charge">-1</parameter>
<parameter name="mass">1</parameter>
</group>
<group name="d" size="37">
<parameter name="charge">-1</parameter>
<parameter name="mass">1</parameter>
</group>
</particleset>
</qmcsystem>
\end{lstlisting}
\begin{lstlisting}[caption=2D Fermi Liquid example (Slater Jastrow wave function) ]
<qmcsystem>
<wavefunction name="psi0" target="e">
<determinantset type="electron-gas" shell="7" shell2="7" randomize="true">
</determinantset>
<jastrow name="J2" type="Two-Body" function="Bspline" print="no">
<correlation speciesA="u" speciesB="u" size="8" cusp="0">
<coefficients id="uu" type="Array" optimize="yes">
</correlation>
<correlation speciesA="u" speciesB="d" size="8" cusp="0">
<coefficients id="ud" type="Array" optimize="yes">
</correlation>
</jastrow>
\end{lstlisting}