SIMIS Seminar on Field Theory and String Theory: The Applications of String Dualities on Black Hole Superradiance and Neutron Star Equation of States

Speaker: Kilar Zhang (Shanghai University)

Abstract: The newly established Seiberg-Witten (SW)/Quasinormal Modes (QNM) correspondence offers an efficient analytical approach to calculate the QNM frequencies, which was only available numerically before. This is based on the fact that both sides are characterized by Heun-type equations. We find that a similar duality exists between Seiberg-Witten theory and black hole superradiance, since the latter can also be linked to confluent Heun equation after proper transformation. Then a dictionary is constructed, with the superradiance frequencies written in terms of gauge parameters. Further by instanton counting, and taking care of the boundary conditions through connection formula, the relating frequencies are obtained analytically, which show consistency with known numerical results.

Neutron stars are among the main targets for gravitational wave observatories, however, their equation of state is still not well established. Mainly phenomenological models with many parameters are widely used by far, while theoretical models are not so practical. In arXiv:1902.08477, a theoretical equation of state with only one parameter is derived from Sakai-Sugimoto model, as an application of AdS/QCD, where pointlike instanton case is taken into consideration. When the tidal deformability constraint from gravitational wave event is satisfied, the maximum mass is about 1.7 solar masses. Now we upgrade this model to instanton gas, with one more variable, the instanton width. This is not naively a free parameter, but a function of the chemical potential. Thus we end up with a more complicated and accurate model, but still with only one adjustable parameter. In this case, we find the maximum mass becomes 1.85 solar masses. This is an encouraging and exiting result, as a theoretically derived model.

Time: 16:00 ~ 17:00, Wed., Apr. 17, 2024

Location: Floor 6, Innovation Center Building 3, Weicheng Road 62, Yangpu District, Shanghai, China

Zoom Meeting No.: 423 317 8953
Password: SIMIS

Organizer: Sen Hu, Andrey Losev, Bong Lian, Wen-Jie Ma, Hao Zou

Scroll to Top