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Events on Wednesday, January 25th, 2023

Atomic Physics Seminar
Precision measurements to search for gravitational waves and dark matter
Time: 11:00 am - 12:00 pm
Place: 5310 Chamberlin Hall
Speaker: Nancy Aggarwal
Abstract: Precision measurements are the key to unlocking various fundamental physics mysteries. In my talk, I will focus on two specific precision measurement experiments - a novel, optomechanical (OM) squeezer for third-generation gravitational wave (GW) detectors, and an experiment searching for the QCD axion mediating new forces in the laboratory. I will also give a sneak-peak into the future research plans for my group.

LIGO and VIRGO detectors deploy squeezed states of electromagnetic vacuum to reduce the quantum noise and enable detection of fainter GWs coming from sources further out in the universe. OM squeezers are based on radiation pressure interaction and hence can be used at any wavelength of light - a big advantage over currently used crystal squeezers that require a special nonlinearity at the desired wavelength. However, OM squeezing comes with its own problems, e.g. Brownian thermal motion washing away the quantum squeezing. For this reason, all previous OM squeezing effors have been at high frequencies and cryogenic temperatures. I will describe what it takes to generate and observe this quantum effect at room temperature and present the first room-temperature optomechanical squeezing results.

The axion is a novel particle proposed to solve the strong-CP problem in QCD, and is also one of the top candidates for dark matter. ARIADNE, under construction right now, will search for spin-dependent forces mediated by the QCD axion in the mass range 10^-6 - 10^-2 eV.
This is a precision measurement experiment that requires isolating a force equivalent to a magnetic field of 10^-20 T between golf-ball sized, moving objects, placed 50 um away from each other. I will describe the experiment concept, engineering challenges associated with it, and current experimental progress, including a new method to isolate magnetic dipoles as small as 10^-9 Am^2.
Host: Thad Walker
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Department Meeting
Time: 12:15 pm - 1:15 pm
Place: B343 Sterling Hall
Speaker: Mark Eriksson, UW-Madison
Host: Mark Eriksson
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