Sensitivity to Dark Energy candidates by searching for four-wave mixing   of high-intensity lasers in the vacuum
  Theoretical challenges to understand Dark Matter and Dark Energy suggest the existence of low-mass and weakly coupling fields in the universe. The quasi-parallel photon-photon collision system (QPS) can provide chances to probe the resonant production of these light dark fields and the induced decay by the coherent nature of laser fields simultaneously. By focusing high-intensity lasers with different colors in the vacuum, new colors emerge as the signature of the interaction. Because four photons in the initial and final states interplay via the dark field exchange, this process is analogous to four-wave mixing in quantum optics, where the frequency sum and difference among the incident three waves generate the fourth wave with a new frequency via the nonlinear property of crystals. The interaction rate of the four-wave mixing process has the cubic dependence on the intensity of each wave. Therefore, if high-intensity laser fields are given, the sensitivity to the weakly coupling of dark fields to photons rapidly increases over the wide mass range below sub-eV. Based on the experimentally measurable photon energies and the linear polarization states, we formulate the relation between the accessible mass-coupling domains and the high-intensity laser parameters, where the effects of the finite spectrum width of pulse lasers are taken into account. The expected sensitivity suggests that we have a potential to explore interactions at the Super-Planckian coupling strength in the sub-eV mass range, if the cutting-edge laser technologies are properly combined. 
Kensuke Homma
hep-ph gr-qc hep-ex