Axion Searches III

The singular behavior of the beta function in axion electrodynamics at large length scales can be resolved by letting the axion-photon coupling run to imaginary values, thereby rendering the Hamiltonian ΡΤ-symmetric (Phys. Rev. D 86.12 (2012): 125014). Such transitions from a Hermitian to a ΡΤ-symmetric Hamiltonian in the infrared may also be important in other contexts, such as in string-inspired Chern-Simons gravity (Phys. Rev. D 110.4 (2024): 045004). However, ΡΤ-symmetric approaches in field theory suffer from long-standing controversies about the physical interpretation of non-hermiticity. Notably, almost all previous works on this problem implicitly assume the orthodox quantum interpretation. In this talk, I will argue for and outline a novel perspective on this problem using the pilot-wave (deBroglie-Bohm) interpretation. I will outline how to implement this interpretation to the ΡΤ-symmetric axion electrodynamic field theory, and highlight its key conclusions regarding the state space, inner product, unitarity etc. I will outline the implications of our approach and future research directions.