Unified view on multiconfigurational time propagation for systems consisting of identical particles

We show that the successful and formally exact multiconfigurational time- dependent Hartree method (MCTDH) takes on a unified and compact form when specified for systems of identical particles (MCTDHF for fermions MCTDHB for bosons). In particular the equations of motion for the orbitals depend explicitly and solely on the reduced one- and two- body density matrices of the system's many- particle wave function. We point out that this appealing representation of the equations of motion opens up further possibilities for approximate propagation schemes. (C) 2007 American Institute of Physics. [DOI: 10.1063/ 1.2771159]