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Parameterized Newtonian Theory. Tomoyuki Nakayama December 11, 2008. Outline. Introduction Why is it useful?/How is it used? Theory General formulation of PPN formalism Application to GR and Brans-Dicke theory Experimental tests Time delay/Light deflection. What is PPN formalism?.
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Parameterized Newtonian Theory Tomoyuki Nakayama December 11, 2008
Outline • Introduction • Why is it useful?/How is it used? • Theory • General formulation of PPN formalism • Application to GR and Brans-Dicke theory • Experimental tests • Time delay/Light deflection
What is PPN formalism? • Parameterized Post-Newtonian formalism express Einstein's’ equation in terms of deviation from Newtonian theory. • Well describes weak field. Bring us further comprehension on Solar-system. • Theoretical foundation for experimental tests for alternative (metric) gravitational theory.
Alternative Gravitational Theories • Metric theories • Have symmetric metric • Test bodies follow geodesics of the metric • In local Lorentz frames, non-gravitational laws are those of SR.
Historical Background • A. S. Eddington (1922) – Analysis of vacuum gravitational field outside the Sun. • K. Nordtvedt (1968) developed the first full PPN formalism. • C. M. Will introduced hydrodynamical description.
PPN Formalism by Will • γ - How much space curvature gij is produced by unit rest mass ? • β - How much nonlinearity is there in the superposition law for gravity g00 ? • β1 - How much gravity is produced by unit kinetic energy ? • β2 - How much gravity is produced by unit gravitational potential energy ρ0 / U ? • β3 - How much gravity is produced by unit internal energy ρ0Π ? • β4 - How much gravity is produced by unit pressure p ? • ζ - Difference between radial and transverse kinetic energy on gravity • η - Difference between radial and transverse stress on gravity • Δ1 - How much dragging of inertial frames g0j is produced by unit momentum ρ0v ? • Δ2 - Difference between radial and transverse momentum on dragging of inertial frames
GR Solution in PPN approximation Brans-Dicke Application of PPN formalism to GR & Brans-Dicke theory
Deflection/Time Delay of Light • One of the PPN parameter (γ) is related to the deflection of light. • It also describes the time delay of light.
Experimental Results • VLBI light deflection 0.02 % from unity (1995). • Cassini spacecraft agrees with GR to 10-3 %. γ-1 = (2.1±2.3)×10-5 (2003)
Summary • PPN formalism, with sophistication of experimental technique, enabled to test the validity of metric theories. • GR has survived through all the experimental testing so far, while myriads of alternative gravitational theories disappeared.
Thank you! • Reference • Misner, Thorne, Wheeler, (1973) Gravitation • Nordvedt (1976) Phys. Rev. 169, 1017-1025 • Will. Living Rev. Relativity 9 (2006), 3 • Chandrasekhar, Phys. Rev. Lett. vol 14, 1965 • Nutku, Astro. Journal, vol 155, March 1969 • Blanchet, Living Rev. Relativity 9 (2006), 4