Quantum Information in the Action of the Cosmic Web: Entropy in a Coherent Universe

Richard Bond (University of Toronto)

November 22, 2023

–

Abstract: Shannon asked the truly great von Neumann, the identifier of (thermal) quantum entropy, what his famous classical information content measure should be called. Johnnie said entropy, nobody understands it anyway – a truism. Nowadays information entropy and thermal entropy have merged as ideas, to me anyway, and expanded to encompass phase info as well as counting info, aka quantum information. Its development and transport through all of the great cosmic epochs of instability accompanying transitions of phase is a unifying story of the Universe. Tis a big topic which I will meander through, from the speculative emergence of coherence through inflation, preheating (the greatest matter-entropy generator), with attention on the cosmic neutrino background decoupling, photon thermal then scattering decouplings, entropy development in the gravitationally-unstable cosmic web. With applications to the cosmic infrared background, line intensity mapping, and the thermal state of clusters and groups, and the quest for entropic relics such as primordial non-Gaussianites. Whew. And that’s not all. The talk will provide a blurred snapshot of where I am in my entropic thinking of cosmic flows, which, after all, is the all-physics flow.