Prospects for detecting periodic or sharp fast-time features in the supernova neutrino lightcurve with IceCube

Neutrinos produced in core-collapse supernova offer a direct probe into the hydrodynamics and energy transport mechanisms during the collapse and play a pivotal role in the shock revival and success of the supernova explosion. Fast-time features of the neutrino luminosity and energy spectrum encode information about phenomena such as turbulence, convection, shock revival and potential quark-hadron phase transitions. In this study, we explore the detection capabilities of large-volume neutrino telescopes with a focus on IceCube and the planned extension IceCube-Gen2. Furthermore, we consider the effect on the detection sensitivity from wavelength shifters through enhanced light collection. A variety of models predict periodic fast-time features in supernova light curves; to quantify their detectability without relying on specific models, we investigate the detector response to a generic parameterisation of such features. We find that independent of feature frequency, IceCube-Gen2 instrumented with wavelength shifters has sensitivity to weaker modulations ($>25\%$ amplitude) as compared to only the strongest modulations ($>50\%$ amplitude) with IceCube. In addition, we examine the sensitivity of the neutrino lightcurve to sharp features from a quark-hadron phase transition. Phase transitions leading to a quark star remnant are detectable with IceCube at $5\sigma$ up to the edge of the Galaxy, and throughout the Small Magellanic Cloud with IceCube-Gen2 equipped with wavelength-shifters. In contrast, models collapsing into a black hole are observable only within the Galaxy, covering $41\%$ of the CCSNe population for IceCube and nearly all ($91\%$) for IceCube-Gen2 complemented by wavelength shifters. These results highlight the potential of IceCube-Gen2 for detecting Galactic sources more reliably and with greater reach.