Exact generator and its high order expansions in the time-convolutionless generalized master equation: Applications to the spin-boson model and exictation energy transfer

The time-convolutionless (TCL) quantum master equation provides a powerful tool to simulate reduced dynamics of a quantum system coupled to a bath. The key quantity in the TCL master equation is the so-called kernel or generator, which describes effects of the bath degrees of freedom. Since the exact TCL generators are usually hard to calculate analytically, most applications of the TCL generalized master equation have relied on approximate generators using second and fourth order perturbative expansions. By using the hierarchical equation of motion (HEOM) and extended HEOM methods, we present a new approach to calculate the exact TCL generator and its high order perturbative expansions. The new approach is applied to the spin-boson model with different sets of parameters, to investigate the convergence of the high order expansions of the TCL generator. We also discuss circumstances where the exact TCL generator becomes singular for the spin-boson model, and a model of excitation energy transfer in the Fenna-Matthews-Olson complex

The code of manzana: invariability, simplicity and changeability

Originally, City is an enormous and intricate system. However, Cerdá simplified the complicated system into a basic unit, the Manzana, which is the unique code belonging to Barcelona found by Cerdá and based on his analysis to the history of the city, life of its citizens, and some other cases. Being at the core of Barcelona Eixample plan, it gradually formulates the enormous city system of Barcelona and thus paves the way for its future development. Starting with the rules of Invariability, Simplicity and Changeability, the three principles in Yi, this thesis regards the Manzana as a Yin-Yang body, with Yin and Yang power complementing and coexisting with each other. By restoring the codes hidden behind the 550 Manzanas in Barcelona, the thesis tries to explore the common ground between the physical space of the city and the binary life of the people living in it.Peer Reviewe

Mean Reversion-Effekte auf dem deutschen Aktienmarkt: Statistische Analysen der Entwicklung des DAX-KGV

This paper investigates mean reversion effects in the German stock market. Recent studies have shown that stock prices tend to follow random walks over short horizons while there is empirical evidence for a mean-reverting behavior over long horizons. Considering fundamental values, we examine mean reversion in the price/earnings ratio of the German blue-chip index DAX for different time horizons to be able to compare the relative strength of the corresponding mean reversion effects.