Illinois Physicists Develop New Framework for Classifying Quantum Phases of Matter
Physicists at the Anthony J. Leggett Institute for Condensed Matter Theory at the University of Illinois Urbana-Champaign have developed a new framework for classifying nonequilibrium quantum phases of matter. This new method addresses the limitations of previous classification schemes, particularly for open, nonequilibrium systems that interact with their environment. The traditional approach, which relies on gapped Hamiltonians and pure states, is often insufficient because real-world quantum states, known as mixed states, decohere and lose their Hamiltonian structure. The Illinois team's framework utilizes an 'entanglement bootstrapping' procedure, which establishes stability criteria to define 'fixed points' in a quantum system. These fixed points act as anchors for defining phases, allowing physicists to identify regions of stable quantum states. The framework introduces three conditions (M0, P0, and M1) to ensure stability and incorporate topological ingredients, enabling a more accurate distinction ...
