Aidan Herderschee, speaking in the IAS High Energy Theory Seminar, argues that extracting signals from inflation requires loop-level, not just tree-level, calculations. Inflation may have occurred at energies up to 10^16 GeV, and the cosmological collider program tries to read the mass and spin of particles present then out of non-Gaussian correlators in the cosmic microwave background and large-scale structure. Herderschee explains that when a heavy particle carries a conserved charge, the leading signal in the bispectrum only appears at one loop, making loop-level Witten diagrams in de Sitter space unavoidable. He adapts tropical geometry, a technique built for multi-loop Feynman integrals in flat space, to evaluate these diagrams in full generality for the first time, working through the one-loop bubble bispectrum from a derivative portal interaction and a triangle diagram, then compares the resulting templates against CMB data.