Roman Höllwieser: Static quark operators based on Laplacian Eigenmodes

Monday 5 Dec 2022, 16:15 → 18:15 Europe/Berlin

Nußallee 14-16/3.013 (HISKP) - Seminar Room II (HISKP)

Static quark operators based on Laplacian Eigenmodes

We investigate a representation of static quark operators based on trial
states formed by eigenvector components of the covariant lattice Laplace
operator. We test the method for computing the static quark-antiquark
potential and compare the results to standard Wilson loop measurements. The
runtime of the new method is significantly smaller when computing the
static potential not only for on-axis, but also for many off-axis
quark-antiquark separations, i.e., when a fine spatial resolution is
required, e.g., for string breaking calculations. We further improve the
signal by using multiple eigenvector pairs, weighted with Gaussian profile
functions of the eigenvalues, providing a basis for a generalized
eigenvalue problem (GEVP), as it was recently introduced to improve meson
spectroscopy. It relies on a technique called distillation which defines
smearing for quark fields as a low-rank linear projection operator into a
small vector space of smooth gauge-covariant fields which has proven to be
both effective and versatile in hadron spectroscopy calculations. The
method presented here can be applied to extract flux tube profiles and
other potential functions for all possible excitations of a gluonic string
with fixed ends, hybrid or tetra-quark potentials, as well as static-light
systems.