6,133 research outputs found

    Observation of quantum spin noise in a 1D light-atoms quantum interface

    Get PDF
    We observe collective quantum spin states of an ensemble of atoms in a one-dimensional light-atom interface. Strings of hundreds of cesium atoms trapped in the evanescent fiel of a tapered nanofiber are prepared in a coherent spin state, a superposition of the two clock states. A weak quantum nondemolition measurement of one projection of the collective spin is performed using a detuned probe dispersively coupled to the collective atomic observable, followed by a strong destructive measurement of the same spin projection. For the coherent spin state we achieve the value of the quantum projection noise 40 dB above the detection noise, well above the 3 dB required for reconstruction of the negative Wigner function of nonclassical states. We analyze the effects of strong spatial inhomogeneity inherent to atoms trapped and probed by the evanescent waves. We furthermore study temporal dynamics of quantum fluctuations relevant for measurement-induced spin squeezing and assess the impact of thermal atomic motion. This work paves the road towards observation of spin squeezed and entangled states and many-body interactions in 1D spin ensembles

    Uncomfortable but Necessary: White Faculty Identity Development and Race Conversations

    Get PDF
    In recent years, diversity, equity, and inclusion initiatives have been highlighted in college mission statements, but there is a gap between college-wide initiatives and classroom practices. Research shows that White Americans, in particular, remain silent, express colorblindness, and incorporate avoidance strategies when discussing race (Bryan et al., 2012). As classrooms become increasingly diverse, White faculty must be equipped to serve all students equitably. To address White faculty discomfort with discussing race in their courses, I provided educational resources and used restorative justice circle practice to create a safe, low stakes environment for faculty to explore this topic. Through circle practices, faculty were able to reflect on their White identity, engage in role-playing, share ideas, and learn alongside one another. White faculty reported being more comfortable engaging in race conversations with students. They also moved beyond conversations to implementation by incorporating diverse authors and identity statements into their syllabi and created plans to adjust class practices to be more inviting and equitable

    Adjustable thermal ''tree''

    Get PDF
    Tree mounts 10 thermocouples on extensible arms to provide a reliable heat profile of conditions within heat treating devices, such as ovens and autoclaves, and within environmental test chambers

    Formalizing Size-Optimal Sorting Networks: Extracting a Certified Proof Checker

    Full text link
    Since the proof of the four color theorem in 1976, computer-generated proofs have become a reality in mathematics and computer science. During the last decade, we have seen formal proofs using verified proof assistants being used to verify the validity of such proofs. In this paper, we describe a formalized theory of size-optimal sorting networks. From this formalization we extract a certified checker that successfully verifies computer-generated proofs of optimality on up to 8 inputs. The checker relies on an untrusted oracle to shortcut the search for witnesses on more than 1.6 million NP-complete subproblems.Comment: IMADA-preprint-c

    Whats Wrong with Punishment

    Get PDF

    Whats Wrong with Punishment

    Get PDF

    Model Data Fusion: developing Bayesian inversion to constrain equilibrium and mode structure

    Full text link
    Recently, a new probabilistic "data fusion" framework based on Bayesian principles has been developed on JET and W7-AS. The Bayesian analysis framework folds in uncertainties and inter-dependencies in the diagnostic data and signal forward-models, together with prior knowledge of the state of the plasma, to yield predictions of internal magnetic structure. A feature of the framework, known as MINERVA (J. Svensson, A. Werner, Plasma Physics and Controlled Fusion 50, 085022, 2008), is the inference of magnetic flux surfaces without the use of a force balance model. We discuss results from a new project to develop Bayesian inversion tools that aim to (1) distinguish between competing equilibrium theories, which capture different physics, using the MAST spherical tokamak; and (2) test the predictions of MHD theory, particularly mode structure, using the H-1 Heliac.Comment: submitted to Journal of Plasma Fusion Research 10/11/200

    Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice

    Full text link
    We demonstrate preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance −14-14 dB below the Poissonian noise level. A mesoscopic ensemble containing a few thousand atoms is trapped in the evanescent field of a nanofiber. The atom number is measured through dual-color homodyne interferometry with a pW-power shot noise limited probe. Strong coupling of the evanescent probe guided by the nanofiber allows for a real-time measurement with a precision of ±8\pm 8 atoms on an ensemble of some 10310^3 atoms in a one-dimensional trap. The method is very well suited for generating collective atomic entangled or spin-squeezed states via a quantum non-demolition measurement as well as for tomography of exotic atomic states in a one-dimensional lattice

    Mainstreaming prevention: Prescribing fruit and vegetables as a brief intervention in primary care

    Get PDF
    This is the author's PDF version of an article published in Public health© 2005.This articles discusses a project at the Castlefields Health Centre in Halton whereby primary care professionals issue a prescription for discounts on fruit and vegetables. The prescription is explicitly linked to the five-a-day message
    • …
    corecore