Magnetic Field Effects in Lowdimensional Quantum Magnets

The Committee to Assess the Current Status and Future Direction of High Magnetic Field Science in the United States was convened by the National Research Council in response to a …

This thesis presents profound insights into the origins and dynamics of beam instabilities using both experimental observations and numerical simulations. When the Recycler Ring, a high-intensity proton beam accelerator at Fermi National Accelerator Laboratory, was commissioned, it became evident that the Recycler beam experiences a very fast instability of unknown nature. This instability was so fast that the existing dampers were ineffective at suppressing it. The nature of this phenomenon, alongside several other poorly understood features of the beam, became one of the biggest puzzles in the accelerator community.

Among the subjects covered in this volume are the topological effects of quantum mechanics, including Bohm-Aharonov and Aharonov-Casher effects and their generalisations; the toroidal moments, anapoles and their generalisations; the numerical investigation of Tonomura experiments testing the foundations of quantum mechanics; the time-dependent Bohm-Aharonov effect, the thorough study of toroidal solenoids and their use as effective transmitters of electromagnetic waves; and the topical questions of the Vavilov-Cherenkov radiation. Furthermore, concrete advice is given for the construction of magnetic and electric solenoids and the performance of experiments on the Bohm-Aharonov effect. In addition, properties of remarkable charge-current configurations and practical applications are studied.

This thesis is devoted to the systematic study of non-local theories that respect Lorentz invariance and are devoid of new, unphysical degrees of freedom. Such theories are attractive for phenomenological applications since they are mostly unconstrained by current experiments. Non-locality has played an increasingly important role in the physics of the last decades, appearing in effective actions in quantum field theory, and arising naturally in string theory and non-commutative geometry.