Olexei I. Motrunich

Nov 27, 2024 | link.aps.org | Sanjay Moudgalya |Technische Universität München |Olexei I. Motrunich

Symmetry is a fundamental concept in physics, which helps us to understand and predict the universal behavior of large classes of systems. Most symmetries considered in the literature, such as “charge conservation,” have very simple structures. However, recent research has uncovered new, more complex symmetries in quantum many-body systems, such as those exhibiting “Hilbert space fragmentation” where the system’s Hilbert space splits into a large number of disconnected sectors.

Jun 27, 2023 | link.aps.org | Sanjay Moudgalya |Olexei I. Motrunich

Abstract For families of Hamiltonians defined by parts that are local, the most general definition of a symmetry algebra is the commutant algebra, i.e., the algebra of operators that commute with each local part. Thinking about symmetry algebras as commutant algebras allows for the treatment of conventional symmetries and unconventional symmetries (e.g., those responsible for weak ergodicity breaking phenomena) on equal algebraic footing.