TheResearch interests of Clifford Will: Experimental Gravity

Selection of Viewgraphs	Testing Scalar-Tensor Gravity We explored the possibility of testing scalar-tensor gravity using gravitational-wave observations of neutron-star inspiral into massive black holes using LIGO (Will 1994). Unfortunately, the bounds achievable are no longer competitive with the current solar-system bound of better than 40,000 (here). But observations by LISA could do better. Scharre and Will (2002),and Will and Yunes (2004), analysed the bounds achievable for a 1.4 solar mass neutron star inspiralling into an intermediate-mass black hole (100 to 10000 solar masses) here. Berti, Buonanno and Will (2005a,2005b) incorporated the effects of aligned spins, which tend to weaken the bounds (example).	Bounding the Mass of the Graviton We studied the possibility of placing a bound on the mass of the graviton using gravitational-wave data from inspiralling compact binaries (Will 1998). Will and Yunes 2004 refined these bounds using recent LISA noise curves here. Berti, Buonanno and Will (2005a,2005b) incorporated the effects of aligned spins, which tend to weaken the bounds. However, if one include higher harmonics of the gravitational waveform, the bounds improve again (Arun and Will 2009); the bounds also improve when the precessions induced by non-aligned spins are included (Stavridis and Will 2009)
Tests of the Weak Equivalence Principle
Tests of Local Lorentz Invariance
Tests of Local Position Invariance
Bounds on the PPN parameter gamma	Testing the "no-hair" theorems with the Galactic Center Black Hole SgrA* We showed that future high-precision observations of the orbits of stars very close to the galactic center black hole could test whether the hole's quadrupole moment matches the no-hair requirement that Q=-J^2/M (Will 2008)	The Multiple Deaths of Whitehead's Theory of Gravity In a jab at some philosophers of science, who continue to love Whitehead's theory, despite evidence presented in 1971 that it violates experiment, we (Gibbons and Will 2006) became serial killers, and showed that the theory violates 5 different kinds of experiments.
Mercury's Perihelion Advance	Other Recent Work
Summary of Bounds on the PPN parameters	Has the speed of gravity been measured? Find out why not here.	We showed (here) that there exists, in Newtonian gravity, stationary axisymmetric systems that admit a third integral of the motion akin to the Carter constant of rotating Kerr black holes provided their multipole moments obey the exact relationship as those of Kerr. Is this a complete fluke or is there something deep here (story)?
The Hulse-Taylor Binary Pulsar	Review Articles
Bounds on variations of fundamental constants	The Confrontation between General Relativity and Experiment. A Living Review (here) Special Relativity: A Centenary Perspective (here) Was Einstein Right? Testing Relativity at the Centenary (here)	Other Review articles: Ingrid Stairs on Binary Pulsars (here) David Mattingly on tests of Lorentz Invariance(here) Jean-Phillippe Uzan on Varying Fundamental Constants (here)