High-energy (TeV-PeV) and ultra-high-energy (> 100 PeV) neutrinos of cosmic origin have a vast potential to probe neutrino physics in regimes of energy and distance otherwise unreachable. Notable examples include precision tests using the flavor composition of the neutrino flux, looking for new neutrino-neutrino interactions, and measuring the neutrino-nucleon cross section beyond accelerator energies. Today, we are already tapping into this potential at high energies, thanks to spectacular discoveries by the IceCube neutrino telescope. In the coming decade, we may extend our reach to ultra-high energies, thanks to an ambitious experimental program under planning. By means of illustration, I will survey the rich landscape of high-energy physics with cosmic neutrinos, from the perspectives of theory and experiment. Along the way, I will point out manifest instances of the natural synergy between low-energy and high-energy experiments, and the unavoidable need to account for astrophysical unknowns.
Dr. Ivan Heredia de la Cruz