Some Conceptual Aspects of Operator Design for Quantum Simulations of Non-Abelian Lattice Gauge Theories

In the Kogut-Susskind formulation of lattice gauge theories, a set of quantum numbers resides at the ends of each link to characterize the vertex-local gauge field. We discuss the role of these quantum numbers in propagating correlations and supporting entanglement that ensures each vertex remains gauge invariant, despite time evolution induced by operators with (only) partial access to each vertex Hilbert space. Applied to recent proposals for eliminating vertex-local Hilbert spaces in quantum simulation, we describe how the required entanglement is generated via delocalization of the time evolution operator with nearest-neighbor controls. These hybridizations, organized with qudits or qubits, exchange classical operator preprocessing for reductions in quantum resource requirements that extend throughout the lattice volume.
Comment: 4 pages, 1 figure, Contribution to proceedings of the 2021 Quantum Simulation for Strong Interactions (QuaSi) Workshops at the InQubator for Quantum Simulation (IQuS)