A Broader Perspective on the Phenomenology of Quantum-Gravity-Induced Infrared/Ultraviolet Mixing

I revisit some arguments that motivate infrared/ultraviolet (IR/UV) mixing, a mechanism such that ultraviolet quantum-gravity structures produce novel features also in a far-infrared regime. On the conceptual side, I highlight in particular an apparently general connection between IR/UV mixing and departures from the standard relativistic symmetries of classical spacetimes. In addition to its conceptual appeal, interest in IR/UV mixing has also been driven by the availability of some opportunities for experimental testing, and my main focus is on phenomenological models of IR/UV mixing that can provide guidance to the experimental efforts. While usually each formulation of IR/UV mixing is investigated within an isolated research program, some parts of my analysis point to possible connections among different formulations and with other quantum-gravity studies.