  We present calculations of the $^{40}$Ca transverse response function
obtained from coupled-cluster theory used in conjunction with the Lorentz
integral transform method. We employ nuclear forces derived at next-to-next-to
leading order in chiral effective field theory with and without $\Delta$
degrees of freedom. We first benchmark this approach on the $^4$He nucleus and
compare both the transverse sum rule and the response function to earlier
calculations based on different methods. As expected from the power counting of
the chiral expansion of electromagnetic currents and from previous studies, our
results retaining only one-body term underestimate the experimental data for
$^4$He by about $20\%$. However, when the method is applied to $^{40}$Ca at the
same order of the expansion, response functions do not lack strength and agree
well with the world electron scattering data. We discuss various sources of
theoretical uncertainties and comment on the comparison of our results with the
available experiments.
