# Time-Dependent Density Functional Theory of Open Quantum Systems in the Linear-Response Regime

 Title: Time-Dependent Density Functional Theory of Open Quantum Systems in the Linear-Response Regime Author: Tempel, David Gabriel; Watson, Mark A.; Olivares-Amaya, Roberto; Aspuru-Guzik, Alán Note: Order does not necessarily reflect citation order of authors. Citation: Tempel, David Gabriel, Mark A. Watson, Roberto Olivares-Amaya, and Alán Aspuru-Guzik. 2011. Time-dependent density functional theory of open quantum systems in the linear-response regime. Journal of Chemical Physics 134(7): 074116. Full Text & Related Files: TDDFT_of_Open_Quantum_Systems_in_the_Linear.pdf (315.5Kb; PDF) Abstract: Time-dependent density functional theory (TDDFT) has recently been extended to describe many-body open quantum systems evolving under nonunitary dynamics according to a quantum master equation. In the master equation approach, electronic excitation spectra are broadened and shifted due to relaxation and dephasing of the electronic degrees of freedom by the surrounding environment. In this paper, we develop a formulation of TDDFT linear-response theory (LR-TDDFT) for many-body electronic systems evolving under a master equation, yielding broadened excitation spectra. This is done by mapping an interacting open quantum system onto a noninteracting open Kohn–Sham system yielding the correct nonequilibrium density evolution. A pseudoeigenvalue equation analogous to the Casida equations of the usual LR-TDDFT is derived for the Redfield master equation, yielding complex energies and Lamb shifts. As a simple demonstration, we calculate the spectrum of a $$C^{2 +}$$ atom including natural linewidths, by treating the electromagnetic field vacuum as a photon bath. The performance of an adiabatic exchange-correlation kernel is analyzed and a first-order frequency-dependent correction to the bare Kohn–Sham linewidth based on the Görling–Levy perturbation theory is calculated. Published Version: doi:10.1063/1.3549816 Other Sources: http://arxiv.org/abs/1004.0189 Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:8403541

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