Online Seminar “Effective speed of gravitational waves and the mirage of modified luminal gravitational wave propagation”

Star-UBB Seminar Series:- Effective speed of gravitational waves and the mirage of modified luminal gravitational wave propagation

The speaker and his team derive an effective equation and action for the propagation of Gravitational Waves(GW), encoding the effects of interaction and self-interaction in a time, frequency and polarization dependent effective speed. In terms of an appropriately defined effective metric, the effective action takes the form a massless Klein-Gordon action. This effective approach predicts that for theories with matter coupled to the Einstein frame metric the ratio between Gravitational and Electromagnetic(EM) luminosity distance depends on the effective speed, while for Jordan frame matter coupling it depends on the effective Planck mass. the speaker discusses how the frequency and polarization dependence of the GW-EM distance ratio and time delay provide a new test of general relativity and its modifications, and more in general of the interaction of GWs with other fields. As an application, consistent with the effective theory of dark energy, he shows that for a luminal modified gravity theory, the gravitational-wave propagation and luminosity distance are the same as in general relativity, but depending on the matter gravity coupling, the electromagnetic luminosity distance can be modified with respect to general relativity.

時間:2024.04.18(四) 16:00~17:30
頻道:Zoom ID:853-7454-4159 ←
講者:Dr. Antonio Enea Romano (Theoretical Physics Department, CERN, CH-1211 Geneva, Switzerland; Universidad de Antioquia, Medellin, Colombia)


Scientific and Technological Advanced Research- Babeș-Bolyai University(Star-UBB) Seminar Series in Gravitation, Cosmology and Astrophysics

Presently a period of rapid and intense change are being witnessed in our understanding of the gravitational force, at a rate that is quickly increasing since the important observational discoveries of the late 1990s. With the advent of new observational techniques, the emergence of important cosmological and astrophysical paradigms can be seen that lead to a deep change in our understanding of the Universe. Astronomical observations strongly suggest that at large scales the force of gravity may not behave according to standard general relativity, and that a generalization of the gravitational action, either at the geometric level, or at the matter level, may be required for a full understanding of the gravitational interaction.

The goal of the present seminar is to bring Theoretical Gravitational Physics closer to the observations and experiments, and to discuss current topics in general relativity, high-energy physics, astrophysics and cosmology.


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