Loop-string-hadron formulation of an SU(3) gauge theory with dynamical quarks
Saurabh V. Kadam, Indrakshi Raychowdhury, Jesse R. Stryker
Abstract
Toward the goal of quantum computing for lattice quantum chromodynamics, we present a loop-string-hadron (LSH) framework in $1+1$ dimensions for describing the dynamics of SU(3) gauge fields coupled to staggered fermions. This novel framework was previously developed for an SU(2) lattice gauge theory in $d\ensuremath{\le}3$ spatial dimensions, and its advantages for classical and quantum algorithms have thus far been demonstrated in $d=1$. The LSH approach uses gauge-invariant degrees of freedoms such as loop segments, string ends, and on-site hadrons, it is free of all non-Abelian gauge redundancy, and it is described by a Hamiltonian containing only local interactions. In this work, the SU(3) LSH framework is systematically derived from the reformulation of Hamiltonian lattice gauge theory in terms of irreducible Schwinger bosons, including the addition of staggered quarks. Furthermore, the superselection rules governing the LSH dynamics are identified directly from the form of the Hamiltonian. The SU(3) LSH Hamiltonian with open boundary conditions has been numerically confirmed to agree with the completely gauge-fixed Hamiltonian, which contains long-range interactions and does not generalize either to periodic boundary conditions or to $d>1$.