6,356 research outputs found

    Anomaly inflow mechanism using Wilson line

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    It is shown that the anomaly inflow mechanism can be implemented using Wilson line in odd dimensional gauge theories. An action of Wess-Zumino-Witten (WZW) type can be constructed using Wilson line. The action is understood in the odd dimensional bulk space-time rather than in the even dimensional boundary. This action is not gauge invariant. It gives anomalous gauge variations of the consistent form on boundary space-times. So it can be used to cancel the quantum anomalies localized on boundary space-times. This offers a new way to cancel the gauge anomaly and construct anomaly-free gauge theory in odd dimensional space-time.Comment: 4 pages, 1 figure; title changed; text and figure improved; references adde

    Stationary Light Pulses in Cold Atomic Media

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    Stationary light pulses (SLPs), i.e., light pulses without motion, are formed via the retrieval of stored probe pulses with two counter-propagating coupling fields. We show that there exist non-negligible hybrid Raman excitations in media of cold atoms that prohibit the SLP formation. We experimentally demonstrate a method to suppress these Raman excitations and realize SLPs in laser-cooled atoms. Our work opens the way to SLP studies in cold as well as in stationary atoms and provides a new avenue to low-light-level nonlinear optics.Comment: 4 pages, 4 figure

    Improving the Performance and Stability of Flexible Pressure Sensors with an Air Gap Structure

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    A highly sensitive flexible resistive pressure sensor based on an air gap structure was presented. The flexible pressure sensor consists of two face to face polydimethylsiloxane (PDMS) films covered with carbon nanotubes (CNTs). The pressure sensor with a 230 μm thickness air gap has relatively high sensitivity (58.9 kPa−1 in the range of 1–5 Pa, 0.66 kPa−1 in the range of 5–100 Pa), low detectable pressure limit (1 Pa), and a short response time (less than 1 s). The test results showed that the pressure sensor with an appropriate air gap has excellent pressure sensitive performance and application potential

    On the Use of Perceptual Properties for Melody Estimation

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    cote interne IRCAM: Liao11aInternational audienceThis paper is about the use of perceptual principles for melody estimation. The melody stream is understood as generated by the most dominant source. Since the source with the strongest energy may not be perceptually the most dominant one, it is proposed to study the perceptual properties for melody estimation: loudness, masking effect and timbre similarity. The related criteria are integrated into a melody estimation system and their respective contributions are evaluated. The effectiveness of these perceptual criteria is confirmed by the evaluation results using more than one hundred excerpts of music recordings
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