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Das digitale Repositorium erfasst, speichert, erhält, erschließt und verbreitet digitale Forschungsergebnisse.2024-02-29T19:27:00ZEssays in Labor Economics
https://hdl.handle.net/20.500.11811/11377
Essays in Labor Economics
Simon, Lenard Paul
As Western societies age, their working-age populations are declining, resulting in a scarcity of labor. Consequently, these societies face reduced production opportunities while shouldering an increasing burden of elderly care. This leads to governments encountering rising expenditures alongside a decreasing tax base. One potential avenue to mitigate this problem is by increasing the labor supply among the working-age population.
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In the canonical model of the labor market, an individual's labor supply is her optimal choice of working hours derived from the trade-off between consumption and leisure, given equilibrium wages and consumption prices. However, in reality, numerous institutional frictions impact labor supply as well, such as misaligned incentives, limited geographic mobility, and inadequate work-family compatibility, among others. Due to these frictions, individuals may choose to work fewer hours than what they would consider optimal when faced with a mere leisure-consumption trade-off. Hence, reducing these frictions could potentially expand the labor supply of the working-age population and, consequently, alleviate the prevailing scarcity of labor in Western societies today. This thesis consists of three independent chapters covering the causes and consequences of such frictions and how they can be eliminated with the help of policies.
2024-02-29T00:00:00ZEssays in Economic Theory
https://hdl.handle.net/20.500.11811/11376
Essays in Economic Theory
Kreutzkamp, Sophie Alexandra
This dissertation consists of three self-contained essays in microeconomic theory and statistics. The first chapter contributes to the literature on information economics. It examines strategic information transmission in a sender-receiver game with endogenous learning. The second chapter on search and matching theory analyses a dynamic matching market in which match values increase over time, and agents have the option to rematch. The third chapter on cluster analysis deals with a constrained clustering model.
2024-02-29T00:00:00ZNeural Network-based Signal Isolation and Cross Section Estimation of the <em>tH</em> Process with the ATLAS Detector
https://hdl.handle.net/20.500.11811/11375
Neural Network-based Signal Isolation and Cross Section Estimation of the <em>tH</em> Process with the ATLAS Detector
Kirfel, Christian
A measurement of the single top quark production in association with a Higgs boson (tH) gives insight into the properties of not only the top quark but also the Higgs boson. The associated production is sensitive to the magnitude and the relative sign of the top quark Higgs boson Yukawa coupling even in the presence of physics beyond the Standard Model. Additionally, the decay of the Higgs boson into two tau leptons, of which successively one or both decay hadronically, allows for precise reconstruction of the Higgs mass. The desired precision is limited by the plethora of background processes with higher cross sections. <br />
In consequence, the analysis is a perfect application area for neural networks for signal isolation. <br />
The method and subsequently the estimation of the cross section are presented using the Run 2 data from the ATLAS detector at the LHC.
2024-02-29T00:00:00ZUnitary fermionic topological field theory
https://hdl.handle.net/20.500.11811/11374
Unitary fermionic topological field theory
Stehouwer, Luuk Daniël
Atiyah's axioms are one way to define rigorously what is a topological quantum field theory. He defined it as a symmetric monoidal functor from a bordism category to the category of vector spaces. To include fermions in this definition, we take instead a functor from a spin bordism category to the category of super vector spaces. In quantum field theory, we can ask whether there is a connection between the spin (integer or half-integer) and its statistics (fermionic or bosonic). The spin-statistics theorem says that every unitary quantum field theory has a spin-statistics connection. In fermionic topological quantum field theory, a spin-statistics connection is a relationship between the 360 degree rotation in spacetime and the fermion parity operator on state space. Not every such field theory has a spin-statistics connection. We construct a symmetric monoidal dagger category of spin bordisms and define a unitary fermionic topological quantum field theory to be a symmetric monoidal dagger functor from this category to the symmetric monoidal category of super Hilbert spaces. The main goal of the thesis is to show that every unitary fermionic topological quantum field theory has a spin-statistics connection.
To achieve this, we develop a theory on how to construct dagger categories from categories with anti-involutions equipped with Hermitian pairings. This construction is analogous to the construction of the dagger category of Hilbert spaces out of the category of vector spaces. In case the category we started with admits duals, we study lifts of the dual functor to a symmetric monoidal dagger functor. As observed by Dave Penneys, dagger dual functors are subtle. We shed some light on their existence and uniqueness. The dagger categories studied in this thesis additionally come equipped with a unitary BZ/2-action. This action is provided by the 360 degree rotation in the bordism category and the parity operator in the category of Hilbert spaces. The essential categorical property of these dagger categories is that they admit dagger dual functors that are `twisted by the BZ/2-action'. Given a bordism dagger category with this property, a dagger functor to super Hilbert spaces will have a spin-statistics connection. We prove that our construction of the spin bordism category satisfies this property and the spin-statistics theorem for topological quantum field theory follows.
2024-02-29T00:00:00Z