The BSSN formalism is a formalism of general relativity that was developed by Thomas W. Baumgarte, Stuart L. Shapiro, Masaru Shibata and Takashi Nakamura between 1987 and 1999. It is a modification of the ADM formalism developed during the 1950s.
The ADM formalism is a Hamiltonian formalism that does not permit stable and long-term numerical simulations. In the BSSN formalism, the ADM equations are modified by introducing auxiliary variables. The formalism has been tested for a long-term evolution of linear gravitational waves and used for a variety of purposes such as simulating the non-linear evolution of gravitational waves or the evolution and collision of black holes.
- Jinho Kim (2008-07-28). "General Relativistic Hydrodynamics Using BSSN formalism" (PDF). Seoul National University. Archived from the original (PDF) on 2012-03-27. Retrieved 2009-10-19.
- Masaru Shibata (October 2004). "Status of numerical relativity". Indian Academy of Sciences. Retrieved 2009-10-19.
- Takashi Nakamura (2006). "Formation of black hole and emission of gravitational waves". Proceedings of the Japan Academy, Series B. 82 (9): 311–327. Bibcode:2006PJAB...82..311N. doi:10.2183/pjab.82.311. PMC 4338837. PMID 25792793.