Probing the quantum vacuum
Recently, a new type of experiments has allowed direct access to vacuum fluctuations using the interaction of two coherent laser pulses with the fluctuating field in a nonlinear crystal.
Using this result, our experimental collaborators from the experimental group of Prof. Faist (ETH Zürich), were able to demonstrate correlations in the vacuum outside the light-cone.
Our theory also predicts how the medium-assisted or polaritonic quantum vacuum can be probed, e.g. close to a material resonance, inside a cavity, or close to a plate with a surface plasmon polariton.