Considering the model of a scalar massive Fermion, it is shown that by means of deformation techniques it is possible to obtain all integrable quantum field theoretic models on two-dimensional Minkowski space which have factorizing S-matrices corresponding to two-particle scattering functions S 2 satisfying S 2 (0) = −1. Among these models there is for example the Sinh-Gordon model. Our analysis provides a complement to recent developments regarding deformations of quantum field theories. The deformed model is investigated also in higher dimensions. In particular, locality and covariance properties are analyzed. The model of a scalar massive Fermion The modelThis section is devoted to the specification of the model which describes a scalar massive Fermion. The model at least goes back to the 1960's and can be found in R. Jost's book [18, p. 103] in connection with weak local commutativity of field operators.In [5], D. Buchholz and S. Summers studied this model in more detail. In particular, they were interested in the degree of nonlocality of the model and investigated if there are any remnants of locality which have physical significance. We recall those findings which are of particular interest for our purposes.

We present a solution method for the inverse scattering problem for integrable twodimensional relativistic quantum field theories, specified in terms of a given massive single particle spectrum and a factorizing S-matrix. An arbitrary number of massive particles transforming under an arbitrary compact global gauge group is allowed, thereby generalizing previous constructions of scalar theories. The two-particle S-matrix S is assumed to be an analytic solution of the Yang-Baxter equation with standard properties, including unitarity, TCP invariance, and crossing symmetry.Using methods from operator algebras and complex analysis, we identify sufficient criteria on S that imply the solution of the inverse scattering problem. These conditions are shown to be satisfied in particular by so-called diagonal S-matrices, but presumably also in other cases such as the O(N )-invariant nonlinear σ-models.

Recent technological advances in vehicle automation and connectivity have furthered the development of a wide range of innovative mobility concepts such as autonomous driving, on-demand services and electric mobility. Our study aimed at investigating the interplay of these concepts to efficiently reduce vehicle counts in urban environments, thereby reducing congestion levels and creating new public spaces to promote the quality of live in urban cities. For analysis, we implemented the aforementioned factors by introducing the concept of robo-taxis as an autonomous and shared mobility service. Using SUMO as the simulation framework, custom functionalities such as ride sharing, autonomous driving and advanced data processing were implemented as python methods via, and around, the TraCI interface. A passenger origin-destination matrix for our region of interest in Milan was derived from publically available mobile phone usage data and used for route input. Key evaluation parameters were the density-flow relationship, particulate-matter emissions, and person waiting- times. Based on these parameters, the critical transition rate from private cars to robo- taxis to reach a free-flow state was calculated. Our simulations show, that a transition rate of about 50% is required to achieve a significant reduction of traffic congestion levels in peak hours as indicated by mean travel times and vehicle flux. Assuming peak- shaving, e.g. through dynamic pricing promised by digitalization, of about 10%, the threshold transition rate drops to 30%. Based on these findings, we propose that introducing a robo-taxi fleet of 9500 vehicles, centered around mid-size 6 seaters, can solve traffic congestion and emission problems in Milan.

We consider a Haag-Kastler net in a positive energy representation, admitting massive Wigner particles and asymptotic fields of massless bosons. We show that states of the massive particles are always vacua of the massless asymptotic fields. Our argument is based on the Mean Ergodic Theorem in a certain extended Hilbert space. As an application of this result we construct the outgoing isometric wave operator for Compton scattering in QED in a class of representations recently proposed by Buchholz and Roberts. In the course of this analysis we use our new technique to further simplify scattering theory of massless bosons in the vacuum sector. A general discussion of the status of the infrared problem in the setting of Buchholz and Roberts is given.

The subject of this thesis is the rigorous construction of quantum field theoretic models with nontrivial interaction. For this task techniques available in the framework of Algebraic Quantum Field Theory are applied and two different approaches are discussed.On the one hand, an inverse scattering problem is considered. A given scattering matrix is thereby taken as the starting point of the construction. In two spacetime dimensions one may work with factorizing scattering matrices which exhibit a simple structure. The particle spectrum taken into account involves an arbitrary number of massive particle species which transform under some global gauge group. It is a known fact that auxiliary fields with weakened localization, namely in wedges, can be constructed. In the main part of this thesis the more involved transition to local theories is shown by means of operator algebraic methods. Concretely, we make use of the so-called modular nuclearity condition. To this end, we investigate certain maps from the wedge algebras, generated by the auxiliary fields, to the considered Hilbert space. Under a very plausible conjecture it is shown that these maps are nuclear, which implies the nontriviality of algebras associated with bounded regions in the sense that the Reeh-Schlieder property holds. This construction method yields a large class of integrable models with factorizing S-matrices in two spacetime dimensions, complying with localization in bounded regions above a minimal size. The constructed family contains, for example, the multifaceted O(N )-invariant nonlinear σ-models.On the other hand, deformation techniques constitute a method of construction which may be applied in arbitrary spacetime dimensions. This approach starts from a known quantum field theoretic model which is subjected to a certain modification. Here, concretely, the model of a scalar massive Fermion was deformed. It is shown that the correspondingly emerging models are based on fields with weakened localization properties again with regard to wedges. Due to this remnant of locality scattering theory can be applied and the two-particle S-matrix can be computed. The resulting scattering matrix depends on the deformation and has a very simple structure, not allowing for particle production nor momentum transfer in scattering processes. However, it differs from the S-matrix of the initial model. By restricting the spacetime dimension to two, it is shown that the considered deformation method yields a large class of integrable models with factorizing S-matrices which, moreover, comply with localization in bounded regions above a minimal size. Among the integrable models arising by deformation is the famous Sinh-Gordon model. ZusammenfassungGegenstand dieser Arbeit ist die rigorose Konstruktion von quantenfeldtheoretischen Modellen mit nicht-trivialer Wechselwirkung. Dazu werden Techniken aus dem Rahmen der Algebraischen Quantenfeldtheorie angewandt und zwei verschiedene Verfahren diskutiert. Zum einen wird ein inverses Streuproblem betrachtet. Dabei ...