Cirio, MauroDebnath, KamanasishLambert, NeillNori, Franco2017-09-052017-09-052017-09-05201710.1103/PhysRevLett.119.053601https://infoscience.epfl.ch/handle/20.500.14299/140165WOS:000406665400007Here we describe how, utilizing a time-dependent optomechanical interaction, a mechanical probe can provide an amplified measurement of the virtual photons dressing the quantum ground state of an ultrastrongly coupled light-matter system. We calculate the thermal noise tolerated by this measurement scheme and discuss an experimental setup in which it could be realized.text::journal::journal article::research article