146,133 research outputs found

    Quantum radiation by an Unruh-DeWitt detector in oscillatory motion

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    Quantum radiated power emitted by an Unruh-DeWitt (UD) detector in linear oscillatory motion in (3+1)D Minkowski space, with the internal harmonic oscillator minimally coupled to a massless scalar field, is obtained non-perturbatively by numerical method. The signal of the Unruh-like effect experienced by the detector is found to be pronounced in quantum radiation in the highly non-equilibrium regime with high averaged acceleration and short oscillatory cycle, and the signal would be greatly suppressed by quantum interference when the averaged proper acceleration is sufficiently low. An observer at a fixed angle would see periods of negative radiated power in each cycle of motion, while the averaged radiated power over a cycle is always positive as guaranteed by the quantum inequalities. Coherent high harmonic generation and down conversion are identified in the detector's quantum radiation. Due to the overwhelming largeness of the vacuum correlators of the free field, the asymptotic reduced state of the harmonics of the radiation field is approximately a direct product of the squeezed thermal states.Comment: 30 pages, 10 figures, partly based on [arXiv:1601.07006

    Measurement of the ZZ production cross section and limits on anomalous neutral triple gauge couplings in proton-proton collisions at sqrt{s} =7 TeV with the ATLAS detector

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    A measurement of the ZZ production cross section in proton-proton collisions at sqrt{s} = 7 TeV using data collected by the ATLAS experiment at the LHC is presented. In a data sample corresponding to an integrated luminosity of 1.02fb-1, 12 events containing two Z boson candidates decaying to electrons and/or muons were observed. The expected background contribution is 0.3^{+0.9}_{-0.3} (stat) ^{+0.4}_{-0.3} (syst) events. The total cross section for on-shell ZZ production has been determined to be \sigma_{ZZ}_{tot}= 8.4^{+2.7}_{-2.3}(stat) ^{+0.4}_{-0.7}(syst)\pm 0.3 (lumi) pb$ and is compatible with the Standard Model expectation of 6.5^{+0.3}_{-0.2} pb calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived.Comment: 8 pages, Proceedings of the DPF-2011 Conference, Providence, RI, August 8-13, 201

    Interrelationships between consumers’ attitudes, behaviour toward organic food and dietary habits

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    This study examined the relationship between Taiwanese consumers’ attitudes and purchase behaviour toward organic food. A preliminary effort was made to identify the influence of consumers’ socio-demographic backgrounds on the variations in their responses. The dietary habits of organic product consumers are another aspect of this study

    Assisted Suicide, the Due Process Clause and Fidelity in Translation

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