Superfluid Optomechanics: Coupling of a Superfluid to a Superconducting Condensate

We investigate the low loss acoustic motion of superfluid $^4$He parametrically coupled to a very low loss, superconducting Nb, TE$_{011}$ microwave resonator, forming a gram-scale, sideband resolved, optomechanical system. We demonstrate the detection of a series of acoustic modes with quality factors as high as $7\cdot 10^6$. At higher temperatures, the lowest dissipation modes are limited by an intrinsic three phonon process. Acoustic quality factors approaching $10^{11}$ may be possible in isotopically purified samples at temperatures below 10 mK. A system of this type may be utilized to study macroscopic quantized motion and as an ultra-sensitive sensor of extremely weak displacements and forces, such as continuous gravity wave sources

Sensor/Actuator Selection for the Constrained Variance Control Problem

The problem of designing a linear controller for systems subject to inequality variance constraints is considered. A quadratic penalty function approach is used to yield a linear controller. Both the weights in the quadratic penalty function and the locations of sensors and actuators are selected by successive approximations to obtain an optimal design which satisfies the input/output variance constraints. The method is applied to NASA's 64 meter Hoop-Column Space Antenna for satellite communications. In addition the solution for the control law, the main feature of these results is the systematic determination of actuator design requirements which allow the given input/output performance constraints to be satisfied

Ultra-high Q Acoustic Resonance in Superfluid 4He

We report the measurement of the acoustic quality factor of a gram-scale, kilo-hertz frequency superfluid resonator, detected through the parametric coupling to a superconducting niobium microwave cavity. For temperature between 400mK and 50mK, we observe a $T^{-4}$ temperature dependence of the quality factor, consistent with a 3-phonon dissipation mechanism. We observe Q factors up to $1.4\cdot10^8$, consistent with the dissipation due to dilute $^3$He impurities, and expect that significant further improvements are possible. These experiments are relevant to exploring quantum behavior and decoherence of massive macroscopic objects, the laboratory detection of continuous wave gravitational waves from pulsars, and the probing of possible limits to physical length scales.Comment: 5 pages, 2 figure

English Writing Through Content and Language Integrated Learning for Korean University Students

The purpose of this project was to discover how to adapt Content and Language Integrated Learning (CLIL) classes to serve the learning needs of Korean university students who want to learn content and English communication skills, particularly writing. The project outlines a goal focused curriculum unit. The curriculum unit includes a content portion focused on discussing current news events, and a portion for teaching writing using those same readings as authentic examples. The writing portion includes strategies to teach basic writing organization such as topic introduction paragraphs, body paragraphs, topic sentences, through process writing, as well as strategies to teach writing styles that fit certain genres. The project includes both detailed lesson plans for teachers as well as handouts for students. The author concludes that while the project is largely a success, in the future the writing portion could be expanded upon