Rocking a scalar to wake
The nature of dark matter and dark energy remains one of the greatest mysteries in physics. In order to understand this dark sector of the Universe, not only particle experiments on the ground but also astrophysical phenomena are important. In particular, the recent direct detections of gravitational waves open a new window to this problem.
Taishi Ikeda and collaborators at IST-Lisbon, Vitor Cardoso and Miguel Zilhao, have recently shown that vibrating neutron stars are a wonderful probe of new physics, and can awaken otherwise dormant degrees of freedom.
They focused on a scalar field coupled to matter, which is one of the simplest models proposed for dark matter and dark energy, and performed a detailed analysis of its behavior around oscillating neutron stars. They discovered that the excited scalar field around the oscillating star can efficiently remove energy away from the star due to two different mechanisms, called parametric and blueshift instabilities. These phenomena may provide a new hint for future searches of dark matter and dark energy using gravitational wave observations.
Instabilities of Scalar Fields around Oscillating Stars
Taishi Ikeda, Vitor Cardoso, and Miguel Zilhão
Phys. Rev. Lett. 127, 191101 (2021)