Could quantum gravity be tested with high intensity Lasers?

Abstract

In quantum gravity theories Planckian behavior is triggered by the energy of {\it elementary} particles approaching the Planck energy, $E_P$, but it's also possible that anomalous behavior strikes systems of particles with total energy near $E_P$. This is usually perceived to be pathological and has been labelled ``the soccer ball problem''. We point out that there is no obvious contradiction with experiment if {\it coherent} collections of particles with bulk energy of order $E_P$ do indeed display Planckian behavior, a possibility that would open a new experimental window. Unfortunately field theory realizations of deformed special relativity never exhibit a ``soccer ball problem''; we present several formulations where this is undeniably true. Upon closer scrutiny we discover that the only chance for Planckian behavior to be triggered by large coherent energies involves the details of second quantization. We find a formulation where the quanta have their energy-momentum (mass-shell) relations deformed as a function of the bulk energy of the coherent packet to which they belong, rather than the frequency. Given ongoing developments in Laser technology, such a possibility would be of great experimental interest.