Searching for New Physics With High-Energy Neutrinos at IceCube

The IceCube neutrino observatory has established the existence of an astrophysical diffuse high-energy neutrino component. This discovery was made using the high-energy starting event sample, which uses a veto to significantly reduce atmospheric background. In this talk I will present the latest astrophysical neutrino flux measurement using high-energy starting events. This latest iteration of the analysis updates the event properties with the newer glacier ice models and has an improved systematic treatment. Using this sample I will report on the first search for anomalous space time effects using astrophysical neutrino flavour data in IceCube. Introducing new effective operators can drive non-standard neutrino flavour mixing, modifying the flavour ratios compared to standard cases. We found no evidence of such flavour anomalies. However, we demonstrate the sensitivity of this new approach goes far beyond any known techniques. Importantly, we achieve the necessary precision to probe new physics using neutrino flavour expected by Planck scale theories. Our quest continues.