Ab-initio variational wave functions for the time-dependent many-electron Schrödinger equation
Jannes Nys, Gabriel Pescia, Alessandro Sinibaldi, Giuseppe Carleo
Abstract
Understanding the real-time evolution of many-electron quantum systems is essential for studying dynamical properties in condensed matter, quantum chemistry, and complex materials, yet it poses a significant theoretical and computational challenge. Our work introduces a variational approach for fermionic time-dependent wave functions, surpassing mean-field approximations by accurately capturing many-body correlations. We employ time-dependent Jastrow factors and backflow transformations, enhanced through neural networks parameterizations. To compute the optimal time-dependent parameters, we employ the time-dependent variational Monte Carlo technique and introduce a new method based on Taylor-root expansions of the propagator, enhancing the accuracy of our simulations. The approach is demonstrated in three distinct systems. In all cases, we show clear signatures of many-body correlations in the dynamics. The results showcase the ability of our variational approach to accurately describe the time evolution, providing insight into quantum dynamical effects in interacting electronic systems, beyond the capabilities of mean-field. Variational parameterization of many-body wavefunctions using neural network quantum states is a powerful technique for studying many-body quantum systems but has been limited to time-independent cases. Nys et al. extend this approach to real-time evolution, providing improved accuracy over traditional methods.