Multiconfigurational time-dependent Hartree method for describing particle loss due to absorbing boundary conditions
This work provides a method for modeling particle loss in quantum systems, which is important for simulations of reactive scattering and open quantum systems.
The authors formulate a multiconfigurational time-dependent Hartree method for a Lindblad master equation to describe particle loss due to absorbing boundary conditions, generalizing standard MCTDH. They demonstrate the formulation with a numerical experiment.
Absorbing boundary conditions in the form of a complex absorbing potential are routinely introduced in the Schrödinger equation to limit the computational domain or to study reactive scattering events using the multi-configurational time-dependent Hartree method (MCTDH). However, it is known that a pure wave-function description does not allow the modeling and propagation of the remnants of a system of which some parts are removed by the absorbing boundary. It was recently shown [S. Selstø and S. Kvaal, J. Phys. B: At. Mol. Opt. Phys. {\bfseries 43} (2010), 065004] that a master equation of Lindblad form was necessary for such a description. We formulate a multiconfigurational time-dependent Hartree method for this master equation, usable for any quantum system composed of any mixture of species. The formulation is a strict generalization of pure-state propagation using standard MCTDH. We demonstrate the formulation with a numerical experiment.