In cosmology we measure correlation functions (cosmological correlators) which we can trace back to the boundary at the end of inflation. In the spirit of the S-matrix in flat space and holography in AdS, the cosmological bootstrap allows us to compute these boundary observables by sidestepping cumbersome Lagrangians, and instead using dS isometries and fundamental principles with no explicit...
This talk will provide an introduction to the first quantised "worldline approach" to quantum field theory. Here, physical information is encoded in path integrals over relativistic point particle trajectories. The path integrals typically lead to "Master Formulae" for scattering amplitudes that combine multiple Feynman diagrams.
I will review the historic development of the worldline...
