diff --git a/Manuscript/eDFT.tex b/Manuscript/eDFT.tex index 5eaef6f..f376f8b 100644 --- a/Manuscript/eDFT.tex +++ b/Manuscript/eDFT.tex @@ -38,6 +38,7 @@ \newcommand{\hT}{\Hat{T}} \newcommand{\vne}{v_\text{ne}} \newcommand{\hWee}{\Hat{W}_\text{ee}} +\newcommand{\WHF}{W_\text{HF}} % functionals, potentials, densities, etc \newcommand{\eps}{\epsilon} @@ -262,7 +263,7 @@ from the exact expression in Eq.~\ref{eq:exact_ens_Hx} that \beq \E{Hx}{\bxi}[\n{}{\bxi,\bxi}] = \sum_{K \geq 0} \xi_K \mel*{\Det{(K),\bxi}}{\hWee}{\Det{(K),\bxi}} \eeq -with $\xi_0=1-\sum_{K>0}\xi_K$ +with $\xi_0 = 1 - \sum_{K>0}\xi_K$ and \beq \E{Hx}{\bw}[\n{}{\bw,\bxi}] = \sum_{K \geq 0} \ew{K} \mel*{\Det{(K),\bxi}}{\hWee}{\Det{(K),\bxi}}, @@ -317,12 +318,12 @@ ensemble KS spinorbitals [from which the latter are constructed] in an atomic or then the density matrix elements obtained from the determinant $\Det{(K)}$ can be expressed as follows in the AO basis: \beq - \bmg^{(K)} \equiv \eGam{\mu\nu}{(K)} = \sum_{\SO{p}{} \in (K)} \cMO{\mu p}{} \cMO{\nu p}{}, + \bGam{(K)} \equiv \eGam{\mu\nu}{(K)} = \sum_{\SO{p}{} \in (K)} \cMO{\mu p}{} \cMO{\nu p}{}, \eeq where the summation runs over the spinorbitals that are occupied in $\Det{(K)}$. Note that the density of the $K$th KS state reads \beq - \n{\bmg^{(K)}}{}(\br{}) = \sum_{\mu\nu} \AO{\mu}(\br{}) \eGam{\mu\nu}{(K)} \AO{\nu}(\br{}). + \n{\bGam{(K)}}{}(\br{}) = \sum_{\mu\nu} \AO{\mu}(\br{}) \eGam{\mu\nu}{(K)} \AO{\nu}(\br{}). \eeq %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Manu's derivation %%% @@ -347,29 +348,29 @@ p}}c^\sigma_{{\nu p}} We can then construct the ensemble density matrix and the ensemble density as follows: \beq - \bmg^{\bw} - = \sum_{K\geq 0} \ew{K} \bmg^{(K)} + \bGam{\bw} + = \sum_{K\geq 0} \ew{K} \bGam{(K)} \equiv \eGam{\mu\nu}{\bw} = \sum_{K\geq 0} \ew{K} \eGam{\mu\nu}{(K)} \eeq and \beq - \n{\bmg^\bw}{}(\br{}) = \sum_{\mu\nu} \AO{\mu}(\br{}) \eGam{\mu\nu}{\bw} \AO{\nu}(\br{}), + \n{\bGam{\bw}}{}(\br{}) = \sum_{\mu\nu} \AO{\mu}(\br{}) \eGam{\mu\nu}{\bw} \AO{\nu}(\br{}), \eeq respectively. The exact energy level expression in Eq.~\eqref{eq:exact_ener_level_dets} can be rewritten as follows: \beq\label{eq:exact_ind_ener_rdm} \begin{split} \E{}{(I)} - & =\Tr[\bmg^{(I)} \bh] - + \frac{1}{2} \Tr[\bmg^{(I)} \bG \bmg^{(I)}] - + \E{c}{{\bw}}[\n{\bmg^{\bw}}{}] + & =\Tr[\bGam{(I)} \bh] + + \frac{1}{2} \Tr[\bGam{(I)} \bG \bGam{(I)}] + + \E{c}{{\bw}}[\n{\bGam{\bw}}{}] \\ - & + \int d\br{} \fdv{\E{c}{\bw}[\n{\bmg^{\bw}}{}]}{\n{}{}(\br{})} - \qty[ \n{\bmg^{(I)}}{}(\br{}) - \n{\bmg^{\bw}}{}(\br{}) ] + & + \int d\br{} \fdv{\E{c}{\bw}[\n{\bGam{\bw}}{}]}{\n{}{}(\br{})} + \qty[ \n{\bGam{(I)}}{}(\br{}) - \n{\bGam{\bw}}{}(\br{}) ] \\ & + \sum_{K>0} \qty(\delta_{IK} - \ew{K}) - \left. \pdv{\E{c}{\bw}[\n{}{}]}{\ew{K}}\right|_{\n{}{} = \n{\bmg^{\bw}}{}} + \left. \pdv{\E{c}{\bw}[\n{}{}]}{\ew{K}}\right|_{\n{}{} = \n{\bGam{\bw}}{}} , \end{split} \eeq @@ -380,20 +381,18 @@ where denote the one-electron integrals matrix. The individual Hx energy is obtained from the following trace \beq - \Tr(\bmg^{(K)} \bG \bmg^{(L)}) - = \sum_{\mu\nu\lambda\omega}\sum_{\sigma=\alpha,\beta}\sum_{\tau=\alpha,\beta}G_{\mu\nu\lambda\omega}^{\sigma\tau} -\eGam{\mu\nu}{(K)\sigma} \eGam{\lambda\omega}{(L)\tau} -\nonumber\\ + \Tr[\bGam{(K)} \bG \bGam{(L)}] + = \sum_{\mu\nu\la\si} \eGam{\mu\nu}{(K)} \eG{\mu\nu\la\si} \eGam{\la\si}{(L)}, \eeq where the two-electron Coulomb-exchange integrals read \beq - G_{\mu\nu\lambda\omega} = - \dbERI{\mu\nu}{\la\si} + G_{\mu\nu\la\omega} + = \dbERI{\mu\nu}{\la\si} = \ERI{\mu\nu}{\la\si} - \ERI{\mu\si}{\la\nu}, \eeq with \beq -\ERI{\mu\nu}{\la\si} = \iint \frac{\AO{\mu}(\br{1}) \AO{\nu}(\br{1}) \AO{\la}(\br{2}) \AO{\si}(\br{2})}{\abs{\br{1} - \br{2}}} d\br{1} d\br{2}. + \ERI{\mu\nu}{\la\si} = \iint \frac{\AO{\mu}(\br{1}) \AO{\nu}(\br{1}) \AO{\la}(\br{2}) \AO{\si}(\br{2})}{\abs{\br{1} - \br{2}}} d\br{1} d\br{2}. \eeq %Note that, in Sec.~\ref{sec:results}, the theory is applied to (1D) spin %polarized systems in which $\eGam{\mu\nu}{(K)\beta}=0$ and @@ -493,18 +492,15 @@ As Hartree and exchange energies cannot be separated in the one-dimension systems considered in the rest of this work, we will substitute the Hartree--Fock density-matrix-functional interaction energy, \beq\label{eq:eHF-dens_mat_func} -W_{\rm -HF}\left[{\bmg}\right]=\frac{1}{2} \Tr(\bmg \, \bG \, \bmg), + \WHF[\bGam{}] = \frac{1}{2} \Tr[\bGam{} \bG \bGam{}], \eeq for the Hx density-functional energy in the variational energy expression of Eq.~\eqref{eq:var_ener_gokdft}: \beq - {\bmg}^{\bw} + \bGam{\bw} \approx \argmin_{\bgam{\bw}} \qty{ - \Tr[\bgam{\bw} \bh ] - + W_{\rm HF}[ \bgam{\bw}] - + \E{c}{\bw}[\n{\bgam{\bw}}{}] + \Tr[\bgam{\bw} \bh ] + \WHF[ \bgam{\bw}] + \E{c}{\bw}[\n{\bgam{\bw}}{}] }. \eeq The minimizing ensemble density matrix fulfills the following @@ -514,12 +510,12 @@ stationarity condition \eeq where $\bS \equiv \eS{\mu\nu} = \braket*{\AO{\mu}}{\AO{\nu}}$ is the metric and the ensemble Fock-like matrix reads \beq - \eF{\mu\nu}{\bw} = \eh{\mu\nu}{\bw} + \sum_{\lambda\si} \eG{\mu\nu\la\si} \eGam{\la\si}{\bw} + \eF{\mu\nu}{\bw} = \eh{\mu\nu}{\bw} + \sum_{\la\si} \eG{\mu\nu\la\si} \eGam{\la\si}{\bw} \eeq with \beq \eh{\mu\nu}{\bw} - = \eh{\mu\nu}{} + \int d\br{} \AO{\mu}(\br{}) \fdv{\E{c}{\bw}[\n{\bmg^\bw}{}]}{\n{}{}(\br{})} \AO{\nu}(\br{}). + = \eh{\mu\nu}{} + \int d\br{} \AO{\mu}(\br{}) \fdv{\E{c}{\bw}[\n{\bGam{\bw}}{}]}{\n{}{}(\br{})} \AO{\nu}(\br{}). \eeq %%%%%%%%%%%%%%% @@ -649,19 +645,17 @@ optimized from a non-local exchange potential [rather than a local one, as expected from Eq.~\eqref{eq:var_ener_gokdft}] is applicable to real (three-dimension) systems. As readily seen from Eq.~\eqref{eq:eHF-dens_mat_func}, \textit{ghost interactions}~\cite{Gidopoulos_2002, Pastorczak_2014, Alam_2016, Alam_2017, Gould_2017} -and curvature~\cite{} will be -introduced in the Hx energy: +and curvature~\cite{} will be introduced in the Hx energy: \beq \begin{split} - W_{\rm HF}[{\bmg}^\bw] - & = \frac{1}{2}\sum_{K\geq 0} \ew{K}^2 - \Tr(\bmg^{(K)} \bG \bmg^{(K)}) + \WHF[\bGam{\bw}] + & = \frac{1}{2} \sum_{K\geq 0} \ew{K}^2 \Tr[\bGam{(K)} \bG \bGam{(K)}] \\ - & + \sum_{L>K\geq 0} \ew{K} \ew{L}\Tr(\bmg^{(K)} \bG \bmg^{(L)}). + & + \sum_{L>K\geq 0} \ew{K} \ew{L}\Tr[\bGam{(K)} \bG \bGam{(L)}]. \end{split} \eeq These errors will be removed when computing individual energies -according to Eq.~\eqref{eq:exact_ind_ener_rdm}.\\ +according to Eq.~\eqref{eq:exact_ind_ener_rdm}. Turning to the density-functional ensemble correlation energy, the following eLDA will be employed: @@ -677,17 +671,16 @@ within eLDA: \beq \begin{split} \E{}{(I)} - & \approx \Tr[\bmg^{(I)} \bh] - + \frac{1}{2} \Tr(\bmg^{(I)} \bG \bmg^{(I)}) + & \approx \Tr[\bGam{(I)} \bh] + \frac{1}{2} \Tr[\bGam{(I)} \bG \bGam{(I)}] \\ - & + \int d\br{} \e{c}{\bw}(\n{\bmg^{\bw}}{}(\br{})) \n{\bmg^{(I)}}{}(\br{}) + & + \int d\br{} \e{c}{\bw}[\n{\bGam{\bw}}{}(\br{})] \n{\bGam{(I)}}{}(\br{}) \\ & - + \int d\br{} \n{\bmg^{\bw}}{}(\br{}) \qty[ \n{\bmg^{(I)}}{}(\br{}) - \n{\bmg^{\bw}}{}(\br{}) ] - \left. \pdv{\e{c}{{\bw}}(\n{}{})}{\n{}{}} \right|_{\n{}{} = n{\bmg^{\bw}}{}(\br{})} + + \int d\br{} \n{\bGam{\bw}}{}(\br{}) \qty[ \n{\bGam{(I)}}{}(\br{}) - \n{\bGam{\bw}}{}(\br{}) ] + \left. \pdv{\e{c}{{\bw}}(\n{}{})}{\n{}{}} \right|_{\n{}{} = \n{\bGam{\bw}}{}(\br{})} \\ - & + \int d\br{} \sum_{K>0} \qty(\delta_{IK} - \ew{K} ) \n{\bmg^{\bw}}{}(\br{}) - \left. \pdv{\e{c}{\bw}(\n{}{})}{\ew{K}} \right|_{\n{}{}=\n{\bmg^{\bw}}{}(\br{})}. + & + \int d\br{} \sum_{K>0} \qty(\delta_{IK} - \ew{K} ) \n{\bGam{\bw}}{}(\br{}) + \left. \pdv{\e{c}{\bw}(\n{}{})}{\ew{K}} \right|_{\n{}{}=\n{\bGam{\bw}}{}(\br{})}. \end{split} \eeq