The decay of excited He from stochastic density-functional theory: a quantum measurementtheory interpretation

Abstract

Recently, time-dependent current-density-functional theory has been extended to includethe dynamical interaction of quantum systems with external environments (Di Ventra andD’Agosta 2007 Phys. Rev. Lett. 98 226403). Here we show that such a theory allows us tostudy a fundamentally important class of phenomena previously inaccessible by standarddensity-functional methods: the decay of excited systems. As an example we study thedecay of an ensemble of excited He atoms, and discuss these results in the context ofquantum measurement theory.