Can LIGO Directly Detect the Scalar Field Dark Energy of 5D Gravity?

The observed acceleration of the present universe is commonly attributed to the existence of dark energy as a dominant component throughout the universe. A direct detection of dark energy has become one of the most important issues in the modern astrophysics and cosmology. Two widely accepted candidates of the dark energy are the cosmological constant Λ and the quintessence. Unlike the cosmological constant, the quintessence is a scalar field Φ that varies throughout spacetime, and has been modelled in various ways such as the four-dimensional (4D) Brans-Dicke scalar-tensor theory of gravitation and the five-dimensional (5D) Kaluza-Klein scalar-vector-tensor theory of gravitation. The scalar field of 5D gravity was shown to be capable of polarizing the space or vacuum and thus can extend the optical length of the path of a laser beam that passes through the polarized space or vacuum. Recently, the author, in terms of his 5D fully covariant Kaluza-Klein scalar-vector-tensor theory of gravitation, has quantitatively related the dielectric constant of the polarized vacuum (and thus the optical length of the path in the polarized vacuum) to the charge-mass ratio of a charged object. This study further demonstrates that the vacuum polarization by the scalar field dark energy of 5D gravity, when the object is highly charged, can be significant enough for the extremely accurate LIGO, which has recently detected first ever the gravitational waves from the binary black hole merger, to directly detect. It is shown that a some-thousand-kilogram sphere electrically charged to tens of kilovolts can polarize the vacuum by its scalar field dark energy and thus extend the optical path length of a laser beam that travels through one LIGO arm with some hundred reflections by approximately 10^-18 m, which is one-order higher than that to be detected by the LIGO detectors. Therefore, being added a highly charged sphere into the experimental setup, LIGO may directly discover the scalar field dark energy of 5D gravity. Details on this new approach and experiment for detecting the scalar field dark energy of 5D gravity will be presented. This work was partially supported by NSF/REU (Grant #: PHY-1559870) at Alabama A & M University.