Only 20% of the matter in our universe is visible to us, while the remaining "dark" matter has so far remained elusive to our best experimental efforts. Upcoming detector technology however makes it possible to search for much lighter dark matter candidates than every before. For these dark matter candidates, DeBroglie wavelength would be comparable or larger than the interparticle spacing in a noble liquid or solid state target. This means that collective effects in the target material, such as phonons, must be included in scattering rate calculations. These calculations take place on the interface between particle physics and theoretical material science.