부산대학교 도서관

We study lattice wouldsheet theory with continuous time describing free motion of a system of bound string bits. We use a non-local lattice derivative that allows us to preserve all the symmetries of the continuum including the worldsheet local symmetries. There exists a ``local correspondence'' between the continuum and lattice theories in the sense that every local dynamical or constraint equation in the continuum also holds true on the lattice, site-wise. We perform a detailed symmetry analysis for the bits and establish conservation laws. In particular, for a bosonic non-linear sigma model with arbitrary target space, we demonstrate both the global symmetry algebra and classical Virasoro algebra (in position space) on the lattice. Our construction is generalizable to higher dimensions for any generally covariant theory that can be studied by expanding around a globally hyperbolic spacetime with conformally flat Cauchy slices.
Comment: 43 pages