Date Thesis Awarded
Honors Thesis -- Open Access
Bachelors of Science (BS)
We consider nonlocal Lorentz-violating theories, with infinite-derivative quadratic terms. The nonlocal modifications in the form of exponential damping in the propagator lead to a better convergence of amplitudes than in the local theories. Moreover, the nonlocal Lorentz-violating theories are ghost-free and unitary when formulated in Minkowski space. We compute the loop effects assuming one-parameter and two-parameter nonlocal functions. By comparing the lower bound of the nonlocality scale with the Planck scale, we rule out these theories. We then review a more general argument, developed by Collins et al. (2004), that a microscopic theory with Lorentz violation around the Planck scale has no suppression at low energy. Additionally, we consider the possibility of suppressing Lorentz violation in these theories when there is a hard cutoff.
Niu, Qian, "Nonlocal Lorentz-violating Modifications of QED" (2021). Undergraduate Honors Theses. William & Mary. Paper 1735.