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Unit 8: Emergent Behavior in Quantum Matter

© Deli Wang Laboratory at UCSD.

Unit Overview

This unit takes an approach to physics that differs markedly from much of what we have encountered in previous units. Rather than cataloging the elementary components of matter, we look at what happens at the macroscopic scale when the interactions of these components with one another and their environment lead to entirely new—emergent—behavior. After introducing the concept of emergence, the unit examines emergent behavior in solid matter, quantum plasmas, and the very different behavior of the liquid forms of two different isotopes of helium (He). The next two sections cover the search for a microscopic theory of superconductivity and its culmination in Bardeen-Cooper-Schrieffer (BCS) theory, which triumphantly accounted for the emergent properties of conventional superconductors. The final three sections focus on efforts to understand emergence in new and different contexts, from freshly discovered forms of superconductivity on Earth to the cosmic superfluidity observed in pulsars—rotating stars made up primarily of neutrons.