2021/11/18 by Christof Gattringer, Gattringer, Christof, Oliver Orasch +1
Physics and Astronomy · #Atomic and Subatomic Physics Research #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #Physics of Superconductivity and Magnetism #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2111.09535
openalex publication_date 2021/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We discuss a new density of states (DoS) approach to solve the complex action\nproblem that is caused by topological terms. The key ingredient is to use open\nboundary conditions for (at least) one of the directions, such that the\nquantization of the topological charge is lifted and the density becomes a\nregular function. We employ the DoS FFA method and compute the density of\nstates as a function of the topological charge. Subsequent integration with\nsuitable factors gives rise to the observables we are interested in. We here\nexplore two test cases: U(1) lattice gauge theory in two dimensions, and SU(2)\nlattice gauge theory in four dimensions. Since the 2-d case has an exact\nsolution we may use it to assess the method, in particular to establish the\nequivalence of the open boundary results with the usual choice of periodic\nboundary conditions. The SU(2) case is a first step of developing the\ntechniques towards their eventual application in full QCD.\n