Interferometric detection of gravitational waves arising from extended theories of gravity

Even if Einstein’s General Relativity achieved a great success and overcame lots of experimental tests, it also showed some shortcomings and flaws which today advise theorists to ask if it is the definitive theory of gravity. In this letter Proceeding we show that, by assuming that advanced projects on the detection of Gravitational Waves (GWs) will improve their sensitivity, allowing to perform a GWs astronomy, accurate angular and frequency dependent response functions of interferometers for GWs arising from various Theories of Gravity, i.e. General Relativity and Extended Theories of Gravity, could aim in discriminating among various theories. Recently, the data analysis of interferometric GWs detectors has been started (for the current status of GWs interferometers see [1]) and the scientific community aims at a first direct detection of GWs in next years. Detectors for GWs will be important for a better knowledge of the Universe and also to confirm or ruling out the physical consistency of General Relativity or of any other theory of gravitation [2, 3, 4, 5, 6, 7]. This is because, in the context of Extended Theories of Gravity, some differences between General Relativity and the others theories can be pointed out starting by the linearized theory of gravity [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]. In this picture, detectors for GWs are in principle sensitive also to a hypothetical scalar component of gravitational radiation, that appears in extended theories of gravity like scalar-tensor gravity [4, 8, 9, 10, 12], bi-metric theory [5], high order theories [2, 3, 6, 7], Brans-Dicke theory [13] and string theory [14].