Bandwidth-Limited Control and Ringdown Suppression in High-Q Resonators

We describe how the transient behavior of a tuned and matched resonator circuit and a ringdown suppression pulse may be integrated into an optimal control theory (OCT) pulse-design algorithm to derive control sequences with limited ringdown that perform a desired quantum operation in the presence of resonator distortions of the ideal waveform. Inclusion of ringdown suppression in numerical pulse optimizations significantly reduces spectrometer deadtime when using high quality factor (high-Q) resonators, leading to increased signal-to-noise ratio (SNR) and sensitivity of inductive measurements. To demonstrate the method, we experimentally measure the free-induction decay of an inhomogeneously broadened solid-state free radical spin system at high Q. The measurement is enabled by using a numerically optimized bandwidth-limited OCT pulse, including ringdown suppression, robust to variations in static and microwave field strengths. We also discuss the applications of pulse design in high-Q resonators to universal control of anisotropic-hyperfine coupled electron-nuclear spin systems via electron-only modulation even when the bandwidth of the resonator is significantly smaller than the hyperfine coupling strength. These results demonstrate how limitations imposed by linear response theory may be vastly exceeded when using a sufficiently accurate system model to optimize pulses of high complexity.Comment: 20 pages, 5 figures; Replaced with version accepted for publication and added journal referenc

CS Circles: An In-Browser Python Course for Beginners

Computer Science Circles is a free programming website for beginners that is designed to be fun, easy to use, and accessible to the broadest possible audience. We teach Python since it is simple yet powerful, and the course content is well-structured but written in plain language. The website has over one hundred exercises in thirty lesson pages, plus special features to help teachers support their students. It is available in both English and French. We discuss the philosophy behind the course and its design, we describe how it was implemented, and we give statistics on its use.Comment: To appear in SIGCSE 201

Nanofluidic tuning of photonic crystal circuits

By integrating soft-lithography-based nanofluidics with silicon nanophotonics, we demonstrate dynamic, liquid-based addressing and high Delta n/n(~0.1) refractive index modulation of individual features within photonic structures at subwavelength length scales. We show ultracompact tunable spectral filtering through nanofluidic targeting of a single row of holes within a planar photonic crystal. We accomplished this with an optofluidic integration architecture comprising a nanophotonic layer, a nanofluidic delivery structure, and a microfluidic control engine. Variants of this technique could enable dynamic reconfiguration of photonic circuits, selective introduction of optical nonlinearities, or delivery of single molecules into resonant cavities for biodetection

Does the Form of Physician Compensation Affect the Quality of Care in Medicaid HMOS?

In the United States a growing fraction of Medicaid participants are enrolled in Health Maintenance Organizations (HMOs). The HMOs contract with physicians to provide health care services to the enrollees. Generally the physicians are compensated either via fee for service (FFS) or capitated arrangements. This paper investigates whether the means by which the physicians are compensated influences the quality of care received by enrollees. Using data for all Medicaid HMO enrollees in a large state, we find that enrollees in HMOs that pay their Primary Care Physicians (PCPs) exclusively via FFS arrangements are more likely to receive services for which the HMO’s PCPs receive additional compensation. Further, these enrollees are less likely to receive services for which the HMO’s PCPs do not receive additional compensation. These findings suggest that financial incentives may influence the behavior of PCPs in Medicaid HMOs, and thus the health care received by Medicaid participants enrolled in HMOs.

Phasing the Mirror Segments of the Keck Telescopes: The Broadband Phasing Algorithm

To achieve its full diffraction limit in the infrared, the primary mirror of the Keck telescope (now telescopes) must be properly phased: The steps or piston errors between the individual mirror segments must be reduced to less than 100 nm. We accomplish this with a wave optics variation of the Shack–Hartmann test, in which the signal is not the centroid but rather the degree of coherence of the individual subimages. Using filters with a variety of coherence lengths, we can capture segments with initial piston errors as large as ± 30 µm and reduce these to 30 nm—a dynamic range of 3 orders of magnitude. Segment aberrations contribute substantially to the residual errors of ~75 nm

Cavity cooling of an ensemble spin system

We describe how sideband cooling techniques may be applied to large spin ensembles in magnetic resonance. Using the Tavis-Cummings model in the presence of a Rabi drive, we solve a Markovian master equation describing the joint spin-cavity dynamics to derive cooling rates as a function of ensemble size. Our calculations indicate that the coupled angular momentum subspaces of a spin ensemble containing roughly $10^{11}$ electron spins may be polarized in a time many orders of magnitude shorter than the typical thermal relaxation time. The described techniques should permit efficient removal of entropy for spin-based quantum information processors and fast polarization of spin samples. The proposed application of a standard technique in quantum optics to magnetic resonance also serves to reinforce the connection between the two fields, which has recently begun to be explored in further detail due to the development of hybrid designs for manufacturing noise-resilient quantum devices.Comment: 14 pages + 5 figure

Myaamiaataweenki eekincikoonihkiinki eeyoonki aapisaataweenki: A Miami Language Digital Tool for Language Reclamation

In 1988, a young graduate student at the University of California, Berkeley began searching for materials on a little-known Algonquian language called Miami, which had ceased to be spoken sometime in the mid-twentieth century. Prompted by curiosity to describe this little-known language, the search uncovered two and a half centuries of documentation. This archival record would serve as the basis for the grammatical reconstruction of what is known today as the Miami-Illinois language, a central Algonquian language of the southern Great Lakes region. These materials are crucial not only to the reconstruction of Miami-Illinois, but also for the growing interests of Myaamia (Miami) people to reclaim their language and cultural heritage. The next twenty years proved to be a struggle in locating, duplicating, organizing and building a physical corpus of data for linguistic analysis and use in community revitalization. Language reconstruction from documentation requires tools for archival interaction and access that linguistically-based software and database applications lacked at the time. This prompted Myaamia researchers and language educators to seek out support for the construction of a digital archival database that met the needs of both tribal linguists and community culture and language revitalizationists. The first version of the Miami-Illinois Digital Archive (MIDA) became a reality in 2012 after support from the National Endowment for the Humanities (NEH) was provided to Miami University’s Myaamia Center to develop this unique research tool. This paper describes the challenges of working with digitized archival materials and how MIDA has filled the software tool gap between archives, linguists and revitalizationists. The Miami-Illinois Digital Archive can be found at http://www.ilaatawaakani.org.National Foreign Language Resource Cente

Ground Testing A 20-Meter Inflation Deployed Solar Sail

Solar sails have been proposed for a variety of future space exploration missions and provide a cost effective source of propellantless propulsion. Solar sails span very large areas to capture and reflect photons from the Sun and are propelled through space by the transfer of momentum from the photons to the solar sail. The thrust of a solar sail, though small, is continuous and acts for the life of the mission without the need for propellant. Recent advances in materials and ultra-low mass gossamer structures have enabled a host of useful space exploration missions utilizing solar sail propulsion. The team of L Garde, NASA Jet Propulsion Laboratory (JPL), Ball Aerospace, and NASA Langley Research Center, under the direction of the NASA In-Space Propulsion Office (ISP), has been developing a scalable solar sail configuration to address NASA s future space propulsion needs. The 100-m baseline solar sail concept was optimized around the one astronomical unit (AU) Geostorm mission, and features a Mylar sail membrane with a striped-net sail suspension architecture with inflation-deployed sail support beams consisting of inflatable sub-Tg (glass transition temperature) rigidizable semi-monocoque booms and a spreader system. The solar sail has vanes integrated onto the tips of the support beams to provide full 3-axis control of the solar sail. This same structural concept can be scaled to meet the requirements of a number of other NASA missions. Static and dynamic testing of a 20m scaled version of this solar sail concept have been completed in the Space Power Facility (SPF) at the NASA Glenn Plum Brook facility under vacuum and thermal conditions simulating the operation of a solar sail in space. This paper details the lessons learned from these and other similar ground based tests of gossamer structures during the three year solar sail project