The Feasibility of a Fully Miniaturized Magneto-Optical Trap for Portable Ultracold Quantum Technology

Experiments using laser cooled atoms and ions show real promise for practical applications in quantum- enhanced metrology, timing, navigation, and sensing as well as exotic roles in quantum computing, networking and simulation. The heart of many of these experiments has been translated to microfabricated platforms known as atom chips whose construction readily lend themselves to integration with larger systems and future mass production. To truly make the jump from laboratory demonstrations to practical, rugged devices, the complex surrounding infrastructure (including vacuum systems, optics, and lasers) also needs to be miniatur- ized and integrated. In this paper we explore the feasibility of applying this approach to the Magneto-Optical Trap; incorporating the vacuum system, atom source and optical geometry into a permanently sealed micro- litre system capable of maintaining $10^{-10}$ mbar for more than 1000 days of operation with passive pumping alone. We demonstrate such an engineering challenge is achievable using recent advances in semiconductor microfabrication techniques and materialsComment: 23 pages, 10 figure

Scientific Knowledge and Philosophic Thought

Originally published in 1986. Are there two kinds of problems—the scientific and the philosophic—each requiring different methods for solution? Or are there, rather, two different ways of approaching a problem, each yielding a different answer according to the method used? Biomedical researcher Sir Harold Himsworth urges scientists not to shy away from using scientific methods to grapple with problems traditionally accepted as belonging to the province of philosophy. The difference between science and philosophy lies not in the problems to which they are directed, Himsworth argues, but rather in the methods they use for solving them. To the scientist, a proposition is something to be investigated; to the philosopher, something to be accepted as a basis for thought. Since the development of the scientific method, substantial progress has been made toward mastering problems in the natural environment. If we are ever to attain a degree of control over problems that derive from human activities, Himsworth claims that we only succeed by approaching them in a comparably objective way

Art and Medicine: A Collaborative Project Between Virginia Commonwealth University in Qatar and Weill Cornell Medicine in Qatar

Four faculty researchers, two from Virginia Commonwealth University in Qatar, and two from Weill Cornell Medicine in Qatar developed a one semester workshop-based course in Qatar exploring the connections between art and medicine in a contemporary context. Students (6 art / 6 medicine) were enrolled in the course. The course included presentations by clinicians, medical engineers, artists, computing engineers, an art historian, a graphic designer, a painter, and other experts from the fields of art, design, and medicine. To measure the student experience of interdisciplinarity, the faculty researchers employed a mixed methods approach involving psychometric tests and observational ethnography. Data instruments included pre- and post-course semi-structured audio interviews, pre-test / post-test psychometric instruments (Budner Scale and Torrance Tests of Creativity), observational field notes, self-reflective blogging, and videography. This book describes the course and the experience of the students. It also contains images of the interdisciplinary work they created for a culminating class exhibition. Finally, the book provides insight on how different fields in a Middle Eastern context can share critical /analytical thinking tools to refine their own professional practices

Marine geophysical studies between northwest Scotland and the Faeroe plateau

A marine geophysical survey of the northern Rockall Trough including the Banks to the north and northwest, the Wyville-Thomson Rise and the Hebridean continental shelf was carried out in 1970 and 1971,Gravity, magnetic and seismic reflection data indicates that the central Rockall Trough is underlain by about 5 km of sediment overlying a normal oceanic crust. The sedimentary thickness decreases to about 3 km and the crust becomes anomalously thick at the northern end of the Trough. Gravity and magnetic interpretation suggests that the Faeroe-Shetland channel is also underlain by anomalously thick oceanic crust. Gravity interpretation indicates that George Bligh, Bill Bailey's and Faeroe Bank are underlain by crust of continental thickness. The Wyville-Thomson Rise, which connects Faeroe Bank to the Scottish continental margin, is composed of two basement ridges of pre-Lower Oligocene age shrouded by sediments up to 1.5 km thick. The north easterly ridge is continuous from the Bank to the continental margin but the south westerly ridge terminates about 50 km from the margin. Magnetic and gravity evidence indicates that the ridges are composed of igneous material and that crustal thickening occurs beneath the ridges. An intrusive complex of unknown age lies beneath the southwest flank of the Rise. Gravity, magnetic and bathymetric interpretation indicates that the Hebridean continental shelf is underlain by Lewisian basement. Gravity and magnetic interpretation indicates that a NNE-SSW trending sedimentary basin about 1.5 km deep and with a partial covering of Tertiary lavas lies between Lewis and the Flannan Isles. Tertiary intrusive complexes, recognisable by their magnetic, gravitational and bathymetric effects, are present beneath St. Kilda, below the continental slope 75 km northwest of St. Kilda and beneath the shelf kO km north-northwest of the Butt of Lewis

Polarization Properties of the "Photon Pistol"

The deterministic single-photon emission by means of STIRAP through the atoms with degenerate levels is studied. The expression for the polarization matrix of the emitted photon is obtained and its dependence on the polarization of the driving laser field and on the initial atomic state is examined.Comment: 13 pages, 3 figure

Harnessing Population Genetics for Pest Management: Theory and Application for Urban Rats

Effective management of rodent pests requires an ecological understanding of how they move through their environment and how those movements influence the invasion, persistence, or reinvasion of problematic colonies. Traditional methodologies used to describe rodent movement patterns, such as mark-recapture, are hindered by their time-consuming nature and limited geographic scope. As such, our understanding of how rodents interact with urban environments remains limited. Population genetic principles and tools have the capacity to greatly increase our understanding of rodent population dynamics, ecological relationships, and movements across space, but this field is often unapproachable to non-scientist pest management professionals (PMPs). In this commentary, we aim to promote collaborative and integrative rodent pest management by introducing relevant population genetic principles, providing examples of their applications in studies of urban brown rats (Rattus norvegicus), and proposing future initiatives that link scientific, private, and government entities. We reinterpret results from a 2018 study of brown rats in Vancouver, British Columbia, Canada to show how genetic relationships among individual brown rats can be used to understand the geographic distribution of genetic clusters (i.e., colonies), natural barriers to migration, and the spatial scale of dispersal. While the 2018 study originally aimed to describe patterns of population genetic structure to understand the influence of urban landscapes on rats, here we describe how these results can be exploited by PMPs to directly inform the creation of management units and decrease the likelihood of rapid post-treatment reinvasion. Further, we discuss the difficulties inherent in population genetic studies and the potential for high-quality model sites to develop generalizable strategies. Overall, we hope to expand the toolbox of PMPs, foster collaboration, and move toward more informed and sustainable management strategies

Control and Manipulation of Cold Atoms in Optical Tweezers

Neutral atoms trapped by laser light are amongst the most promising candidates for storing and processing information in a quantum computer or simulator. The application certainly calls for a scalable and flexible scheme for addressing and manipulating the atoms. We have now made this a reality by implementing a fast and versatile method to dynamically control the position of neutral atoms trapped in optical tweezers. The tweezers result from a spatial light modulator (SLM) controlling and shaping a large number of optical dipole-force traps. Trapped atoms adapt to any change in the potential landscape, such that one can re-arrange and randomly access individual sites within atom-trap arrays.Comment: 6 pages, 4 figure

Linear array CMOS detectors for laser doppler blood flow imaging

Laser Doppler blood flow imaging is well established as a tool for clinical research. The technique has considerable potential as an aid to diagnosis and as a treatment aid in a number of situations. However, to make widespread clinical use of a blood flow imager feasible a number of refinements are required to make the device easy to use, accurate and safe. Existing LDBF systems consist of 2D imaging systems, and single point scanning systems. 2D imaging systems can offer fast image acquisition time, and hence high frame rate. However, these require high laser power to illuminate the entire target area with sufficient power. Single point scanning systems allow lower laser power to be used, but building up an image of flow in skin requires mechanical scanning of the laser, which results in a high image acquisition time, making the system awkward to use. A new approach developed here involves scanning a line along a target, and imaging the line with a 1D sensor array. This means that only one axis of mechanical scanning is required, reducing the scanning speed, and the laser power is vastly reduced from that required for a 2D system. This approach lends itself well to the use of integrated CMOS detectors, as the smaller pixel number means that a linear sensor array can be implemented on an IC which has integrated processing while keeping overall IC size, and hence cost, lower than equivalent 2D imaging systems. A number of front-end and processing circuits are investigated in terms of their suitability for this application. This is done by simulating a range of possible designs, including several logarithmic pixels, active pixel sensors and opamp-based linear front-ends. Where possible previously fabricated ICs using similar sensors were tested in a laser Doppler flowmetry system to verify simulation results. A first prototype IC (known as BVIPS1) implements a 64x1 array of buffered logarithmic pixels, chosen for their combination of sufficient gain and bandwidth and compact size. The IC makes use of the space available to include two front-end circuits per pixel, allowing other circuits to be prototyped. This allows a linear front-end based on opamps to be tested. It is found that both designs can detect changes in blood flow despite significant discrepancies between simulated and measured IC performance. However, the signal-noise ratio for flux readings is high, and the logarithmic pixel array suffers from high fixed pattern noise, and noise and distortion that makes vein location impossible. A second prototype IC (BVIPS2) consists of dual 64x1 arrays, and integrated processing. The sensor arrays are a logarithmic array, which addresses the problems of the first IC and uses alternative, individually selectable front-ends for each pixel to reduce fixed-pattern noise, and an array of opamp-based linear detectors. Simulation and initial testing is performed to show that this design operates as intended, and partially overcomes the problems found on the previous IC - the IC shows reduced fixed pattern noise and better spatial detection of blood flow changes, although there is still significant noise