2T-physics and its application in cosmology
Shih-Hung Chen · 2015
This dissertation addresses the recent progress in 2T-physics and 2T field theory that I have participated in. To make it more logically connected, the dissertation contains not only my own work but also some of the previous work by Professor Bars, especially in chapter 1, where a lot of research at the worldline level was done by Professor Bars and his colleagues. My contribution to the field is mainly from chapter 2 to chapter 4. Each chapter focuses on one paper that I have published with Professor Bars as well as my colleague Guillaume Qu�lin. A review of the fundamental principle of 2T-physics is presented in the first chapter. In the second chapter, I explain how 2T-physics is generalized to 2T field theory, which describes that the creation and annihilation of particles and their interactions. The interactions among dynamical 2T-fields were missing without 2T field theory formalism. My works in 2T field theory extend the duality relation between one-time (1T) systems from the worldline level to the field theory level. The predictions of 2T-physics are also demonstrated in this chapter. Those predictions include revealing hidden symmetries of many 1T field theories and the duality relations among them. In the third chapter, I have generalized the gravitational background fields in the 2T field theory to dynamical gravitational fields. The properties of the conformal shadow that produces usual General Relativity from 2T gravity have been studied extensively. These properties could be used for future phenomenological tests of 2T-physics in 1T shadows. In chapter four, I explicitly apply the method of 2T-physics to solve a scalar-tensor theory that is difficult to solve exactly without 2T method. Using this technique, I build an interesting phenomenological model of inflation that matches most of the current observational constraints coming from WMAP 5 years? data except for the running of the spectral index.