  We present a study of the mid-IR (MIR) emission of quiescent galaxies (QGs)
beyond the local universe. Using deep $JWST$ imaging in the SMACS-0723 cluster
field we identify a mass limited ($M_{*} >10^{9}$M$_{\odot}$) sample of
intermediate redshift QGs ($0.2<z<0.7$) and perform modeling of their
rest-frame UV to MIR photometry. We find that QGs exhibit a range of MIR
spectra that are composed of a stellar continuum and a dust component that is
1-2 orders of magnitude fainter to that of star-forming galaxies. The observed
scatter in the MIR spectra, especially at $\lambda_{\rm rest} > 5 \mu$m, can be
attributed to different dust continuum levels and/or the presence of Polycyclic
Aromatic Hydrocarbons (PAHs) features. The latter would indicate enhanced 11.3-
and 12.7 $\mu$m PAHs strengths with respect to those at 6.2- and 7.7$ \mu$m,
consistent with the observed spectra of local ellipticals and indicative of
soft radiation fields. Finally, we augment the average UV-to-MIR spectrum of
the population with cold dust and gas emission in the far-IR/mm and construct a
panchromatic UV-to-radio SED that can serve as a template for the future
exploration of the interstellar medium of $z>0$ QGs with ALMA and $JWST$.
