12:00–1:00 pm ERC 401
Gautam Venugopalan (Stanford University) "Suspended animation - optical tweezers as a fundamental physics probe"
Quantum-limited metrology has opened new frontiers in several landmark experiments in the last decade. The field of “levitodynamics”, where an object is subject to a trapping potential that provides a restoring force against gravity, is one such area. Among the available levitation schemes, optical tweezers are attractive because of the availability of ultra-stable laser sources, and the ability to read out the motion of the trapped object close to (or even below) the shot-noise limit. I will describe a single-beam, vertically oriented optical trapping scheme that uses ∼ 10μm sized silica spheres to realize exquisite force sensitivity. Coupled with a novel measurement scheme to efficiently reject electromagnetic backgrounds that often plague such measurements, we have demonstrated its sensitivity to monopole charges on the trapped object as small as ∼ 3.3 × 10−5 e. With modest improvements, we anticipate using the next iteration of this experiment to look for deviations from Newtonian gravity at the 1μm – 100μm length scale, providing a complementary technique to previous searches that have largely relied on variations of mechanical springs. Finally, the rich dynamics of the levitated object offers the opportunity to cool specific modes to their quantum ground state, making the system a playground for testing quantum mechanics at the mesoscopic scale.
