ABSTRACT
Special relativity and the equivalence principle can be considered as the most basic foundations of the theory of gravity. However, string theories allow for or even predict the violation of these laws (see [1, 2] and references therein). Many experiments hunt for these exotics (figure 1), which have been tested to a very high level of accuracy [3] for ordinary matter - generally for quarks and leptons of the first generation. These precision tests of local Lorentz invariance - violation of the equivalence principle
l"igure 1. The hunt for exotics is still going on and may be successful in neutrinoless double beta decay
should produce a similar effect [4] - probe for any dependence of the (nongravitational) laws of physics on a laboratory's position, orientation or velocity relative to some preferred frame of reference, such as the frame in which the cosmic microwave background is isotropic .
