Jesse Berezovsky (Physics, CWRU)

Date: Thu. February 20th, 2025, 4:00 pm-5:00 pm
Location: Rockefeller 301

Catland: A Journey Through the Quantum Multiverse

100 years after the origins of quantum theory, there remains no consensus on how best to understand what this theory is telling us about our universe. Quantum theory rests on two legs. The first is the idea that matter can be described as a wave, whose evolution in the non-relativistic case is given by the Schrodinger equation. The second is the idea that we cannot directly observe these waves, but instead postulate a set of probabilistic rules that govern what we do observe when we make a “measurement.” The first leg results in phenomena such as interference and tunneling that would be surprising if one imagined matter to consist of billiard-ball-like particles. Stranger still is the phenomenon of entanglement of multiple particles. But the second leg is truly puzzling. In the last few decades, a picture has started to develop of how the second leg may not be required at all, but instead may emerge as a consequence of the first leg. In this talk, I will present some simple examples of simulated few-particle wave functions that illustrate how our perceived classical reality can emerge from the behavior of quantum waves. This emergence will be illustrated by a demonstration of a macroscopic quantum measurement. The essential result is that the enormously complicated behavior of quantum entanglement at the macroscopic scale can be usefully understood using the concept of a multiverse: that the strange quantum superpositions that we know to occur for a few microscopic particles are amplified into “many worlds” that all exist simultaneously, and play out independently of each other.

This talk will be based on material drawn from my web tutorial here