We pioneer new techniques to test weak-field gravity, search for new interactions weaker than gravity, and develop instrumentation for LIGO.


1) Search for violations of Einstein's Equivalence Principle and the Newtonian inverse-square law.

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

3) Develop precision instrumentation for the Laser Interferometer Gravitational Wave Observatory (LIGO).

Selected Publications:

A torsion-balance search for ultra low-mass bosonic dark matter Phys. Rev. D 105, 042007 (2022)
Initial Results from the LIGO Newtonian Calibrator Phys. Rev. D 104, 082006 (2021)
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), Phys. Rev. Lett. 100, 041101 (2008)
Gravitational constraints on new particle physics Phys. Rev. Lett 98, 131104 (2007)
Torsion Balance Test of Spin-Coupled Forces Physical Review Letters 97, 021603 (2006)
Measurement of the gravitational constant Phys. Rev. Lett 85 2869 (2000)

Eöt-Wash in the news:

LiveScience: Physicists who disproved '5th force' win $3 million 'Breakthrough' prize
Nature: Even at short range, Newton’s law still rules
Ars Technica: Experiment finds that gravity still works down to 50 micrometers
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 PHY-1607385, PHY-1607391, PHY-1912380, and PHY1912514. 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.


Group Wiki: https://eotwash.npl.washington.edu/eotwiki/index.php/Main_Page