Exact form factors in integrable quantum field theories: the sine-Gordon model (II)

A general model independent approach using the `off-shell Bethe Ansatz' is presented to obtain an integral representation of generalized form factors. The general techniques are applied to the quantum sine-Gordon model alias the massive Thirring model. Exact expressions of all matrix elements are obtained for several local operators. In particular soliton form factors of charge-less operators as for example all higher currents are investigated. It turns out that the various local operators correspond to specific scalar functions called p-functions. The identification of the local operators is performed. In particular the exact results are checked with Feynman graph expansion and full agreement is found. Furthermore all eigenvalues of the infinitely many conserved charges are calculated and the results agree with what is expected from the classical case. Within the frame work of integrable quantum field theories a general model independent `crossing' formula is derived. Furthermore the `bound state intertwiners' are introduced and the bound state form factors are investigated. The general results are again applied to the sine-Gordon model. The integrations are performed and in particular for the lowest breathers a simple formula for generalized form factors is obtained.Comment: LaTeX, 53 pages, Corrected typo

The Form Factors and Quantum Equation of Motion in the sine-Gordon Model

Using the methods of the 'form factor program' exact expressions of all matrix elements are obtained for several operators of the quantum sine-Gordon model alias the massive Thirring model. A general formula is presented which provides form factors in terms of an integral representation. In particular charge-less operators as for example the current of the topological charge, the energy momentum tensor and all higher currents are considered. In the breather sector it is found the quantum sine-Gordon field equation holds with an exact relation between the 'bare' mass and the normalized mass. Also a relation for the trace of the energy momentum is obtained. All results are compared with Feynman graph expansion and full agreement is found.Comment: TCI-LaTeX, 21 pages with 2 figur

Design of CubeSats for Formation Flying & for Extreme Low Earth Orbit

This project handled the design and analysis of the attitude determination and control, command and data handling, and structural subsystems of CubeSats designed for two distinct missions. One mission was to fly a CubeSat in extreme low earth orbit, while the other was to fly two CubeSats in formation. Attitude sensors and an onboard computer selected in previous years' designs were reviewed and updated. Structural analysis simulations were conducted in ANSYS. Additionally, the test bed for an attitude determination and control system experiment designed and constructed by the students in MAD-1701 was improved upon, and an attitude control system was designed. Finally, recommendations were provided for future teams looking to further develop this experimental setup

Breaking the Cycle of Congestion: An Examination of Bicycle Traffic in Copenhagen

Due to the large number of cyclists in Copenhagen, bicycle traffic congestion has recently become a significant problem. By modeling currently congested intersections in Copenhagen and interviewing experts, we evaluated strategies to reduce congestion along with the social implications of implementing those strategies. Each strategy we tested had different effects on the resulting traffic behavior, each with respective pros and cons. Based on our data, we found that altering the traffic light cycles and increasing the bicycle lane widths were the most effective strategies, although we concluded that changing traffic light timings was the most viable. Implementing these strategies will reduce traffic congestion at intersections throughout Copenhagen and allow traffic to flow more smoothly

Studies on plasma-sprayed thermal barrier coatings

The emphasis of this work has been the fundamental characterization of the material properties of thermal barrier coatings. Tests have been carried out on plasma sprayed ZrO//2-8wt%Y//2O//3 and ZrO//2-12wt%Y//2//3 (YSZ) coatings. The thermal expansion coefficient ( alpha ) is anisotropic in the longitudinal direction (planar to the substrate) compared to the transverse orientation (perpendicular to the substrate). The magnitude of alpha is dependent on prior heat treatment of the coating. The coating, deposited onto a superalloy substrate, was thermally cycled to 1200 degree C and failure followed via acoustic emission (AE) techniques. AE count rate distribution varies with temperature. Relationships of this nature lead to an understanding of cracking mechanisms within the coating