Figure 3

Figure 3: Selected tests of local position invariance via gravitational redshift experiments, showing bounds on $α$ , which measures degree of deviation of redshift from the formula $Δ ν∕ν = ΔU ∕c2$ . In null redshift experiments, the bound is on the difference in $α$ between different kinds of clocks.

	Abstract
1	Introduction
2	Tests of the Foundations of Gravitation Theory
	2.1	The Einstein equivalence principle
	2.2	Theoretical frameworks for analyzing EEP
	2.3	EEP, particle physics, and the search for new interactions
3	Metric Theories of Gravity and the PPN Formalism
	3.1	Metric theories of gravity and the strong equivalence principle
	3.2	The parametrized post-Newtonian formalism
	3.3	Competing theories of gravity
4	Tests of Post-Newtonian Gravity
	4.1	Tests of the parameter $γ$
	4.2	The perihelion shift of Mercury
	4.3	Tests of the strong equivalence principle
	4.4	Other tests of post-Newtonian gravity
	4.5	Prospects for improved PPN parameter values
5	Strong Gravity and Gravitational Waves: Tests for the 21st Century
	5.1	Strong-field systems in general relativity
	5.2	Motion and gravitational radiation in general relativity: A history
	5.3	Compact binary systems in general relativity
	5.4	Compact binary systems in scalar–tensor theories
6	Stellar System Tests of Gravitational Theory
	6.1	The binary pulsar and general relativity
	6.2	A zoo of binary pulsars
	6.3	Binary pulsars and alternative theories
	6.4	Binary pulsars and scalar–tensor gravity
7	Gravitational-Wave Tests of Gravitational Theory
	7.1	Gravitational-wave observatories
	7.2	Gravitational-wave amplitude and polarization
	7.3	Gravitational-wave phase evolution
	7.4	Speed of gravitational waves
8	Astrophysical and Cosmological Tests
9	Conclusions
	Acknowledgments
	References
	Footnotes
	Updates
	Figures
	Tables