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In the Newman–Penrose (NP) formalism of general relativity, independent components of the Ricci tensors of a four-dimensional spacetime are encoded into seven (or ten) Ricci scalars which consist of three real scalars , three (or six) complex scalars and the NP curvature scalar . Physically, Ricci-NP scalars are related with the energy–momentum distribution of the spacetime due to Einstein's field equation. ==Definitions== Given a complex null tetrad and with the convention , the Ricci-NP scalars are defined by〔Jeremy Bransom Griffiths, Jiri Podolsky. ''Exact Space-Times in Einstein's General Relativity''. Cambridge: Cambridge University Press, 2009. Chapter 2.〕〔Valeri P Frolov, Igor D Novikov. ''Black Hole Physics: Basic Concepts and New Developments''. Berlin: Springer, 1998. Appendix E.〕〔Abhay Ashtekar, Stephen Fairhurst, Badri Krishnan. ''Isolated horizons: Hamiltonian evolution and the first law''. Physical Review D, 2000, 62(10): 104025. Appendix B. (gr-qc/0005083 )〕 (where overline means complex conjugate) Remark I: In these definitions, could be replaced by its trace-free part 〔 or by the Einstein tensor because of the normalization (i.e. inner product) relations that : : Remark II: Specifically for electrovacuum, we have , thus and therefore is reduced to Remark III: If one adopts the convention , the definitions of should take the opposite values;〔Ezra T Newman, Roger Penrose. ''An Approach to Gravitational Radiation by a Method of Spin Coefficients''. Journal of Mathematical Physics, 1962, 3(3): 566-768.〕〔Ezra T Newman, Roger Penrose. ''Errata: An Approach to Gravitational Radiation by a Method of Spin Coefficients''. Journal of Mathematical Physics, 1963, 4(7): 998.〕〔Subrahmanyan Chandrasekhar. ''The Mathematical Theory of Black Holes''. Chicago: University of Chikago Press, 1983.〕〔Peter O'Donnell. ''Introduction to 2-Spinors in General Relativity''. Singapore: World Scientific, 2003.〕 that is to say, after the signature transition. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Ricci scalars (Newman–Penrose formalism)」の詳細全文を読む スポンサード リンク
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