Lessons on electronic decoherence in molecules from exact modeling

TL;DR

This paper presents exact quantum mechanical simulations of electronic decoherence in a model molecular system, explicitly including both electronic and nuclear degrees of freedom, to establish a benchmark and explore fundamental decoherence mechanisms.

Contribution

The study introduces an exact computational approach for modeling electronic decoherence in molecules, explicitly accounting for electron-nuclear interactions using the Su-Schreefer-Heeger Hamiltonian.

Findings

Provides a benchmark for electronic decoherence dynamics.

Demonstrates the impact of electron-electron interactions on decoherence.

Offers a platform to test and improve approximation schemes.

Abstract

Electronic decoherence processes in molecules and materials are usually thought and modeled via schemes for the system-bath evolution in which the bath is treated either implicitly or approximately. Here we present computations of the electronic decoherence dynamics of a model many-body molecular system described by the Su-Schreefer-Heeger Hamiltonian with Hubbard electron-electron interactions using an exact method in which both electronic and nuclear degrees of freedom are taken into account explicitly and fully quantum mechanically. To represent the electron-nuclear Hamiltonian in matrix form and propagate the dynamics, the computations employ a Jordan-Wigner transformation for the fermionic creation/annihilation operators and the discrete variable representation for the nuclear operators. The simulations offer a standard for electronic decoherence that can be used to test approximations. They also provide a useful platform to answer fundamental questions about electronic decoherence that cannot be addressed through approximate or implicit schemes.