Adaptive time-dependent coupled cluster method for multiparticle wavepacket dynamics
This work provides a new theoretical framework for quantum dynamics simulations, potentially improving accuracy for complex molecular systems.
The authors derived a variational formulation of coupled cluster theory with time-dependent single-particle functions, enabling high-accuracy simulations of complex multiparticle wavepacket dynamics. The method generalizes standard coupled cluster response theory and includes time-dependent Hartree-Fock as a trivial case.
A dynamical formulation of coupled cluster theory is derived using a variational principle. By allowing time-dependent single-particle functions, a high degree of adaptivity is introduced, allowing complex systems to be simulated with high accuracy. Equations of motion are derived which are shown to be suitable for computer implementation. The method, called adaptive time-dependent coupled cluster, is a strict generalization of the formulation used in standard coupled cluster response theory, and also represents a systematic hierarchy of size-consistent approximations, including standard time-dependent Hartree--Fock as a trivial case.