| In my dissertation, I have investigated some of the basic principles and foundations of gauge theories of gravity. A gauge theory is a theory that uses gauge potentials to preserve a global symmetry on a local level. I gave special considerations to two main assumptions, namely the hypothesis of locality and the Einstein principle of equivalence. I have also discussed concepts that are global in nature, such as radiation and alternatives to the hypothesis of locality.; The investigation of the hypothesis of locality is of importance, since it is related to very basic measurements, such as the measurement of spatial distances and temporal durations. The basic nongravitational laws of physics refer to ideal inertial observers. On the other hand, actual observers are all (more or less) noninertial, i.e. accelerated, for example laboratories fixed on the rotating Earth; therefore, it is necessary to give a theoretical description of the measurements of accelerated observers.; I have demonstrated that within the confines of classical, i.e. nonquantum physics, there exist basic limitations on length measurement by accelerated observers in Minkowski space-time that follow from the hypothesis of locality. I have found that consistency can be achieved only in a rather limited neighborhood around the observer with linear dimensions that are negligibly small compared to the characteristic acceleration length of the observer.; I have shown that the principle of equivalence allows for general affine connections between neighboring affine tangential spaces. In general, this means that general metric-affine gauge theories of gravity could be viable. Specifically, I have studied teleparallel theories. One particular teleparallel theory is, in fact, equivalent to Einstein's theory of gravity. |
