Development of new technologies for precision torsion-balance experiments

Abstract

Torsion balances were first used for precision measurements of physics centuries ago and continue to be used to probe physical forces and test for new physics. Improving beyond current limits requires better sensitivity and better ability to monitor or reduce unwanted systematic effects. This dissertation describes two technologies developed to aid in these improvements. The first is an interferometric quasi-autocollimator---an optical readout device inspired by quantum weak-value amplification and capable of an angular sensitivity of 10 picoradians per root hertz. The second is a gravity gradiometer torsion balance with a mass quadrupole that can be changed in situ. This balance uses a wirelessly powered non-magnetic rotary actuator, also developed as part of this work, which will enable additional approaches to systematics and torsion-balance science.