Markus Quandt – författare

In den Wochen vor der Bundestagswahl 2002 deutete alles auf einen Regierungswechsel hin. Gleichwohl wurde die rot-grüne Bundesregierung unter Gerhard Schröder am 22. September 2002 knapp im Amt bestätigt. Dieser Last-Minute-Swing wird im Zusammenhang mit langfristigen Veränderungstrends des Wählerverhaltens als das Ergebnis einer zunehmenden Individualisierung der Wahlentscheidung gedeutet. Kurzfristige Einflussfaktoren gewinnen demnach gegenüber den langfristigen Prägekräften der Wahlentscheidung an Bedeutung. Professionelle Wahlkampfführung und ein geschicktes Themenmanagement werden zu wichtigen Voraussetzungen des Wahlerfolgs. Vor diesem allgemeinen Hintergrund wird aufgezeigt, welche Rolle der drohende Krieg im Irak, die Flutkatastrophe und die "TV-Duelle" von Gerhard Schröder und Edmund Stoiber für die Wahlentscheidung bei der Bundestagswahl 2002 gespielt haben.

In this monograph we apply scattering theory methods to calculations in quantum ?eld theory, with a particular focus on properties of the quantum vacuum. These methods will provide e?cient and reliable solutions to a - riety of problems in quantum ?eld theory. Our approach will also elucidate in a concrete context many of the subtleties of quantum ?eld theory, such as divergences, regularization, and renormalization, by connecting them to more familiar results in quantum mechanics. We will use tools of scattering theory to characterize the spectrum of energyeigenstatesinapotentialbackground,hencethetermspectralmethods. This mode spectrum comprises both discrete bound states and a continuum of scattering states. We develop a powerful formalism that parameterizes the e?ects of the continuum by the density of states, which we compute from scattering data. Summing the zero-point energies of these modes gives the energy of the quantum vacuum, which is one of the central quantities we study.Althoughthemostcommonlystudiedbackgroundpotentialsarisefrom static soliton solutions to the classical equations of motion, these methods are not limited to such cases.

In this monograph we apply scattering theory methods to calculations in quantum ?eld theory, with a particular focus on properties of the quantum vacuum. These methods will provide e?cient and reliable solutions to a - riety of problems in quantum ?eld theory. Our approach will also elucidate in a concrete context many of the subtleties of quantum ?eld theory, such as divergences, regularization, and renormalization, by connecting them to more familiar results in quantum mechanics. We will use tools of scattering theory to characterize the spectrum of energyeigenstatesinapotentialbackground,hencethetermspectralmethods. This mode spectrum comprises both discrete bound states and a continuum of scattering states. We develop a powerful formalism that parameterizes the e?ects of the continuum by the density of states, which we compute from scattering data. Summing the zero-point energies of these modes gives the energy of the quantum vacuum, which is one of the central quantities we study.Althoughthemostcommonlystudiedbackgroundpotentialsarisefrom static soliton solutions to the classical equations of motion, these methods are not limited to such cases.