204 research outputs found

    Single spin universal Boolean logic

    Full text link
    Recent advances in manipulating single electron spins in quantum dots have brought us close to the realization of classical logic gates based on representing binary bits in spin polarizations of single electrons. Here, we show that a linear array of three quantum dots, each containing a single spin polarized electron, and with nearest neighbor exchange coupling, acts as the universal NAND gate. The energy dissipated during switching this gate is the Landauer-Shannon limit of kTln(1/p) [T = ambient temperature and p = intrinsic gate error probability]. With present day technology, p = 1E-9 is achievable above 1 K temperature. Even with this small intrinsic error probability, the energy dissipated during switching the NAND gate is only ~ 21 kT, while today's nanoscale transistors dissipate about 40,000 - 50,000 kT when they switch

    An integrated software system for geometric correction of LANDSAT MSS imagery

    Get PDF
    A system for geometrically correcting LANDSAT MSS imagery includes all phases of processing, from receiving a raw computer compatible tape (CCT) to the generation of a corrected CCT (or UTM mosaic). The system comprises modules for: (1) control of the processing flow; (2) calculation of satellite ephemeris and attitude parameters, (3) generation of uncorrected files from raw CCT data; (4) creation, management and maintenance of a ground control point library; (5) determination of the image correction equations, using attitude and ephemeris parameters and existing ground control points; (6) generation of corrected LANDSAT file, using the equations determined beforehand; (7) union of LANDSAT scenes to produce and UTM mosaic; and (8) generation of output tape, in super-structure format

    Radiological Pitfalls in Patients with Inducible Dynamic Proptosis

    Get PDF
    We report two patients presenting with marked clinical unilateral enophthalmos who had positional variability and dynamic proptosis on valsalva. On orbital imaging, enophthalmos was not documented and in fact, globe proptosis of the same side was reported for one of the patients. During CT and MRI scanning patients are often instructed to hold their breath to eliminate motion artefact. This may inadvertently induce dynamic proptosis. The radiological pitfalls of imaging patients with inducible dynamic proptosis and how to identify such patients are discussed

    Scanning Quantum Decoherence Microscopy

    Full text link
    The use of qubits as sensitive magnetometers has been studied theoretically and recent demonstrated experimentally. In this paper we propose a generalisation of this concept, where a scanning two-state quantum system is used to probe the subtle effects of decoherence (as well as its surrounding electromagnetic environment). Mapping both the Hamiltonian and decoherence properties of a qubit simultaneously, provides a unique image of the magnetic (or electric) field properties at the nanoscale. The resulting images are sensitive to the temporal as well as spatial variation in the fields created by the sample. As an example we theoretically study two applications of this technology; one from condensed matter physics, the other biophysics. The individual components required to realise the simplest version of this device (characterisation and measurement of qubits, nanoscale positioning) have already been demonstrated experimentally.Comment: 11 pages, 5 low quality (but arXiv friendly) image

    Resource Utilization Due to Breakthrough Pain in Patients With Chronic Painful Conditions

    Get PDF
    Objectives Primary: To capture healthcare resource consumption and work loss in a population of patients with chronic pain who have pain flares from one or more non-cancer conditions. Secondary: To explore the relationship between anxiety, depression, and pain in this population

    Perception of Breakthrough Pain in Patients with Chronic Painful Conditions

    Get PDF
    Objective: To understand how patients with chronic non-cancer pain define and describe pain flares

    Renormalized Path Integral for the Two-Dimensional Delta-Function Interaction

    Get PDF
    A path-integral approach for delta-function potentials is presented. Particular attention is paid to the two-dimensional case, which illustrates the realization of a quantum anomaly for a scale invariant problem in quantum mechanics. Our treatment is based on an infinite summation of perturbation theory that captures the nonperturbative nature of the delta-function bound state. The well-known singular character of the two-dimensional delta-function potential is dealt with by considering the renormalized path integral resulting from a variety of schemes: dimensional, momentum-cutoff, and real-space regularization. Moreover, compatibility of the bound-state and scattering sectors is shown.Comment: 26 pages. The paper was significantly expanded and numerous equations were added for the sake of clarity; the main results and conclusions are unchange
    • …
    corecore