# Lessons on electronic decoherence in molecules from exact modeling. (arXiv:1801.05846v1 [physics.chem-ph])

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.