We pioneer new techniques in precision studies of weak-field gravity and search for possible new interactions weaker than gravity.


1) Search for experimental signs of quantum gravity that violate Einstein's Equivalence Principle and/or the Newtonian inverse-square law.

2) Probe the largely unexplored region of possible interactions weaker than gravity.

3) Make sensitive tests for new interactions that couple to electron spin.

4) Develop sensitive low-noise instrumentation for the Laser Interferometer Gravitational Wave Observatory.

5) Provide understanding of small short range forces that may affect the LISA gravitational wave experiment.


Selected Publications:

New Test of the Gravitational 1/r2 Law at Separations down to 52 μm Phys. Rev. Lett. 124, 101101  (2020)
Short-Range, Spin-Dependent Interactions of Electrons: A Probe for Exotic Pseudo-Goldstone Bosons Phys. Rev. Lett. 115, 201801 (2015)
Torsion-balance tests of the weak equivalence principle Class. Quantum Grav. 29, 184002 (2012)
Review of torsion-balance experiments Prog. Part. Nucl. Phys 62, 102 (2009)
Gravitational constraints on new particle physics Phys. Rev. Lett 98, 131104 (2007)
Test of gravity below 100 microns Phys. Rev. Lett 98, 021101 (2007)
Torsion Balance Test of Spin-Coupled Forces Physical Review Letters 97, 021603 (2006)
Review of Inverse Square Law Tests Ann. Rev. Nucl. Part. Sci., 53 77 (2003)

Eöt-Wash on the web:

The Economist: The dark side of the universe
Nature: Frontier experiments: Tough science
Discovery Channel: Through The Wormhole with Morgan Freeman: Are There More Than Three Dimensions?
Physics for the 21st century: Gravity. Check out the video!!
Scientific American: String Theory's Extra Dimensions Must Be Less Than Half the Width of a Human Hair


Acknowledgement of Financial Support:

Our work is primarily supported by the National Science Foundation under Grant No. 0969199. We are grateful for resources from the Department of Energy support for the Center for Experimental Nuclear Physics and Astrophysics. Our experiments are conducted on the University of Washington campus.