59 research outputs found

    Measuring multipartite entanglement via dynamic susceptibilities

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    Entanglement plays a central role in our understanding of quantum many body physics, and is fundamental in characterising quantum phases and quantum phase transitions. Developing protocols to detect and quantify entanglement of many-particle quantum states is thus a key challenge for present experiments. Here, we show that the quantum Fisher information, representing a witness for genuinely multipartite entanglement, becomes measurable for thermal ensembles via the dynamic susceptibility, i.e., with resources readily available in present cold atomic gas and condensed-matter experiments. This moreover establishes a fundamental connection between multipartite entanglement and many-body correlations contained in response functions, with profound implications close to quantum phase transitions. There, the quantum Fisher information becomes universal, allowing us to identify strongly entangled phase transitions with a divergent multipartiteness of entanglement. We illustrate our framework using paradigmatic quantum Ising models, and point out potential signatures in optical-lattice experiments.Comment: 5+5 pages, 3+2 figure

    Resource flows and levels of spending for the response to HIV and AIDS in Belarus

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    <p>Abstract</p> <p>Background</p> <p>Belarus has a focused HIV epidemic concentrated among injecting drug users, female sex workers and men who have sex with men. However, until 2008, Belarus had no way of evaluating HIV spending priorities. In 2008, Belarus committed to undertaking a comprehensive National AIDS Spending Assessment (NASA) in order to analyze HIV spending priorities. NASA was used to 'follow the money' from the funding sources to agents and providers, and eventually to beneficiary populations.</p> <p>Findings</p> <p>Belarus spent the majority of its funding on prevention, diagnosis and treatment of sexually transmitted infections and on securing the blood supply. International donors and NGOs working within Belarus spent the majority of their funding on preventative activities for high risk groups while Global Fund to Fight AIDS, Tuberculosis, and Malaria (GFATM) solely funded antiretroviral treatment.</p> <p>Conclusions</p> <p>The data and experience obtained through conducting NASA will help build capacity for future resource tracking activities for HIV and other health priorities. This experience established the foundation for enhanced and future consistent quality-reporting of National Health Accounts. Monitoring the flow of resources for Belarus' HIV response provides valuable strategic information that can improve operations and planning as well as mobilize greater resources. NASA offers Belarusian policy makers an overview of HIV activities that merit their priority attention. In addition, the findings from Belarus are particularly relevant for the rest of the Commonwealth of Independent States due to their similar epidemiological profiles and centrally planned systems. The Belarusian government faces future challenges, especially in increasing public investments in HIV prevention for female sex workers and their clients, men who have sex with men, and among intravenous drug users.</p

    Self-affirmation improves music performance among performers high on the impulsivity dimension of sensation seeking

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    In the light of evidence that self-affirmation can mitigate the negative effects of stress on outcomes, this study tested whether a self-affirmation manipulation could improve undergraduate students’ achievement in a formal musical performance examination. The study also investigated the association between impulsivity and music performance and explored whether impulsivity moderated any impact of self-affirmation on exam performance. Methods: At baseline, participants provided demographic information and completed the UPPS-P Impulsive Behaviour Scale (short-form), which assesses five dimensions of impulsivity (negative and positive urgency, lack of premeditation, lack of perseverance, and sensation seeking). In the subsequent 14 days, participants (N = 65) completed either a self-affirmation manipulation or a control task, before reading a message about the impact of practice on music performance. Music performance was formally assessed 14 days later. Findings: Sensation seeking was the only dimension of impulsivity associated with exam performance, with participants high in sensation seeking receiving lower grades. Critically, self-affirmation promoted better music performance among those high in sensation seeking. Discussion: Self-affirmation may provide a useful intervention to augment the performance of musicians who would otherwise perform worse than their counterparts under formal evaluative circumstances, such as those high in sensation seeking

    Low loss coatings for the VIRGO large mirrors

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    présentée par L. PinardThe goal of the VIRGO program is to build a giant Michelson type interferometer (3 kilometer long arms) to detect gravitational waves. Large optical components (350 mm in diameter), having extremely low loss at 1064 nm, are needed. Today, the Ion beam Sputtering is the only deposition technique able to produce optical components with such performances. Consequently, a large ion beam sputtering deposition system was built to coat large optics up to 700 mm in diameter. The performances of this coater are described in term of layer uniformity on large scale and optical losses (absorption and scattering characterization). The VIRGO interferometer needs six main mirrors. The first set was ready in June 2002 and its installation is in progress on the VIRGO site (Italy). The optical performances of this first set are discussed. The requirements at 1064 nm are all satisfied. Indeed, the absorption level is close to 1 ppm (part per million), the scattering is lower than 5 ppm and the R.M.S. wavefront of these optics is lower than 8 nm on 150 mm in diameter. Finally, some solutions are proposed to further improve these performances, especially the absorption level (lower than 0.1 ppm) and the mechanical quality factor Q of the mirrors (thermal noise reduction)

    Detection chain and electronic readout of the QUBIC instrument

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    The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10⁻¹⁶ W/√Hz

    Detection chain and electronic readout of the QUBIC instrument

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    The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10⁻¹⁶ W/√Hz

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
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