deletions | additions       diff --git a/section_What_do_we_mean__.tex b/section_What_do_we_mean__.tex  index ac46ec0..776863d 100644  --- a/section_What_do_we_mean__.tex  +++ b/section_What_do_we_mean__.tex 
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In quantum chemistry~\cite{Mori_S_nchez_2008}, there is a classification of the errors introduced by the use of approximate density functionals, as being of two types, static correlation and dynamic correlation\cite{Yang_2012}. Similar ideas, also appear in the solid state context, but the nomenclature is exchanged. A \emph{static} self energy (i.e. a self energy which varies weakly with frequency at low energies) corresponds to the concept of dynamical correlations.  % TODO: Define the problem: What IS design of correlated materials? Describe the intersection of materials design with correlated materials. Also describe the need for large computable databases.  % [Chuck: cite examples where LDA+U doesn't quite construct the correct convex hull -- maybe Gutzwiller could do better.]  % Materials design also necessarily involves handling and organizing large bodies of data since the process of check => machine learning.  % The ability to design new materials with desired properties is a key challenge.  % Its solution would have far-reaching implications in both fundamental science  % and technological applications. Whether it is a new class of semiconductors for  % the next generation of integrated circuits, superconductors for dissipationless  % transport of electricity, or thermoelectrics for efficient recovery of waste  % heat, advances in underlying materials results in advances in technology.  % Ingredients of materials design.  % The underlying workhorse for all materials design is a box which takes as input  % the coordinates of the atoms within a unit cell and produces the total energy  % of the configuration. For materials without partially-filled $d$ or $f$ shells,  % density functional theory performs quite well, providing total energies that  % are accurate to within 50meV.  % \begin{itemize}  % \item define the material design challenge  % \item say that in weakly correlated systems it has been fulfilled within DFT. Can mention Zunger’s Heussler compound.