[2022.09.29] 12:30-13:30 ❘ Dr. Wei-Xiang Feng (UC Riverside):Gravothermal phase transition, black holes and space dimensionality.
| ******** NCTS/CTC/NTHU HEP Seminar ******** Speaker： Mr. Wei-Xiang Feng ( UC Riverside ) Title ： Gravothermal phase transition, black holes and space dimensionality Time ： 12:30-13:30, Thursday, 2022/9/29 Place ： R019, Physics Building, Nat'l Tsing Hua Univ. Host ： Prof. Po-Yen Tseng (NTHU) Abstract: In the framework of gravothermal evolution of an ideal monatomic fluid, I examine the dynamical instability of the fluid sphere in (N+1) dimensions by exploiting Chandrasekhar’s criterion to each quasi-static equilibrium along the sequence of the evolution. Once the instability is triggered, it would probably collapse into a black hole if no other interaction halts the process. From this viewpoint, the privilege of (3+1)-dimensional spacetime is manifest, as it is the marginal dimensionality in which the ideal monatomic fluid is stable but not too stable. Moreover, it is the unique dimensionality that allows stable hydrostatic equilibrium with positive cosmological constant. While all higher dimensional (N>3) spheres are genuinely unstable. In contrast, in (2+1)-dimensional spacetime it is too stable either in the context of Newton’s theory of gravity or Einstein’s general relativity. The implications of spacetime dimensionality will be briefly discussed. Online link: https://cern.zoom.us/j/ ****************************** If you will attend the seminar and would like to have a lunchbox on that day, please register for it online by 10:00AM Sept. 28th (Wednesday morning). Late registration will not be accepted. Link for the online registration: https://forms. *Note: 1. The lunchboxes will only be prepared for the participation of professors and postdoctoral researchers. Please sign up for your attendance and receive your lunchbox at the lobby of NCTS on 5F between 11:40AM - 12:00PM on Sept. 29th. Thank you. 2. In order to prevent the potential spread of COVID-19, we suggest that you bring your own face mask and wear it while attending the seminar.
|