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Item type:Publication, Access status: with files , Quantum information theory for engineers : free climbing through physics and probability(2019-06-13)The aim of this supplement to my lecture notes ''Quantum Information Theory for Engineers: An Interpretative Approach`` is to develop a probabilistic framework that can be applied to classical stochastic problems as well as to quantum mechanical problems with interference phenomena. In particular, many paradoxes in quantum theory are demystified. Our approach replaces spacetime by a trinity of time, namely future, present, and past leading to a distinction between outcomes, possibilities, and internal possibilities. Our approach unifies the Dirac-Feynman rules with classical probability theory. We discuss polarization and slit experiments, the measurement problem, quantum electrodynamics, and Hardy's paradox, a spectacular experimental setup where simple logical arguments about its physical constraints lead to a surprising contradiction.Publicationtype: Book498 306 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Quantum information theory for engineers: an interpretative approach(2017)These lecture notes comprise lectures on quantum computing and quantum information theory that I taught during the last ten years for students of electrical engineering, mathematics, and computer science. The notes present an alternative entrance to quantum information theory that is suitable for students studying engineering, but perhaps also for people interested in physics and philosophy of physics.Publicationtype: Book1864 1215 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Rigorous results in electronic structure calculationsElectronic structure calculations, in particular the computation of the ground state energy, lead to challenging problems in optimization. These problems are of enormous importance in quantum chemistry for calculations of properties of solids and molecules. Minimization methods for computing the ground state energy can be developed by employing a variational approach, where the second-order reduced density matrix defines the variable. This concept leads to large-scale semidefinite programming problems that provide a lower bound for the ground state energy. Upper bounds of the ground state energy can be calculated for example with the Hartree-Fock method. However, Nakata, Nakatsuji, Ehara, Fukuda, Nakata, and Fujisawa observed, that due to numerical errors the semidefinite solver produced erroneous results with a lower bound significantly larger than the Hartree-Fock upper bound. Violations within one mhartree were observed. We present here a method for solving electronic structure problems where all numerical errors are taken into consideration. In particular this method provides rigorous error bounds without violations as mentioned above.Publicationtype: Journal Article47