  Direct detection experiments are still one of the most promising ways to
unravel the nature of dark matter. To fully understand how well these
experiments constrain the dark matter interactions with the Standard Model
particles, all the uncertainties affecting the calculations must be known. It
is especially critical now because direct detection experiments recently moved
from placing limits only on the two elementary spin independent and spin
dependent operators to the complete set of possible operators coupling dark
matter and nuclei in nonrelativistic theory. In our work, we estimate the
effect of nuclear configuration-interaction uncertainties on the exclusion
bounds for one of the existing xenon-based experiments for all fifteen
operators. We find that for operator number 13 the $\pm 1\sigma$ uncertainty on
the coupling between the dark matter and nucleon can reach more than 50% for
dark matter masses between 10 and 1000 GeV. In addition, we discuss how quantum
computers can help to reduce this uncertainty and how the uncertainties are
affected for couplings obtained for the nonrelativistic reductions of the
relativistic interactions.
