📣 IF invites you to the No.18 IF Colloquium (Online Seminar Series)
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📌 Title: ” Inspiral gravitational waves from compact binary systems in scalar-tensor theories ”
📌 Speaker : Prof. Shinji Tsujikawa, Ph.D., Professor of Physics at Department of Physics, Waseda University, Japan
📌 Abstract : In a class of scalar-tensor theories with the speed of gravity equivalent to that of light, we study gravitational radiation emitted during the inspiral phase of compact binary systems. We compute the waveform of scalar perturbations under a post-Newtonian expansion of energy-momentum tensors of point-like particles that depend on a scalar field. This scalar mode not only gives rise to breathing and longitudinal polarizations of gravitational waves, but it is also responsible for scalar gravitational radiation in addition to energy loss associated with transverse and traceless tensor polarizations. We calculate the Fourier-transformed gravitational waveform of two tensor polarizations under a stationary phase approximation and show that the resulting waveform reduces to the one in a parametrized post-Einsteinian (ppE) formalism. The ppE parameters are directly related to a scalar charge in the Einstein frame, whose existence is crucial to allow the deviation from General Relativity (GR). We apply our general framework to several concrete theories and show that a new theory of spontaneous scalarization with a higher-order scalar kinetic term leaves interesting deviations from GR that can be probed by the observations of gravitational waves emitted from neutron star-black hole binaries.
📌 Keywords : Compact Binary Systems , Inspiral Gravitacional waves
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📌 Date and Time : 02:00 p.m. – 03:00 p.m. Monday, March 13, 2023
📌 Venue : The Academia Room (with online broadcasting)
📌 Live on #IFChannel : https://www.youtube.com/live/vlB-jN8dlOs?si=cQzYCSJEjXMajaZ9
#GravitacionalWaves #Cosmology #Physics #TheoreticalPhysics #IFNU #PhysicsNaresuan #IFColloquium
