Quantum embedding based on the (one-electron reduced) density matrix is revisited by means of unitary Householder transformation. While being exact and equivalent to (but formally simpler than) theory (DMET) in non-interacting case, resulting transformed functional (Ht-DMFET) preserves, construction, single-particle character bath when electron correlation introduced. In Ht-DMFET, projected "im...

Abstract The physical properties of a quantum many-body system can, in principle, be determined by diagonalizing the respective Hamiltonian, but dimensions its matrix representation scale exponentially with number degrees freedom. Hence, only small systems that are described through simple models can tackled via exact diagonalization. To overcome this limitation, numerical methods based on reno...

It is proved that the one-particle density matrix $\gamma(x, y)$ for multi-particle systems analytic away from nuclei and diagonal $x = y$.