2,071 research outputs found

    Certified quantum non-demolition measurement of material systems

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    An extensive debate on quantum non-demolition (QND) measurement, reviewed in Grangier et al. [Nature, {\bf 396}, 537 (1998)], finds that true QND measurements must have both non-classical state-preparation capability and non-classical information-damage tradeoff. Existing figures of merit for these non-classicality criteria require direct measurement of the signal variable and are thus difficult to apply to optically-probed material systems. Here we describe a method to demonstrate both criteria without need for to direct signal measurements. Using a covariance matrix formalism and a general noise model, we compute meter observables for QND measurement triples, which suffice to compute all QND figures of merit. The result will allow certified QND measurement of atomic spin ensembles using existing techniques.Comment: 11 pages, zero figure

    How far does the analogy between causal horizon-induced thermalization with the standard heat bath situation go?

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    After a short presentation of KMS states and modular theory as the unifying description of thermalizing systems we propose the absence of transverse vacuum fluctuations in the holographic projections as the mechanism for an area behavior (the transverse area) of localization entropy as opposed to the volume dependence of ordinary heat bath entropy. Thermalization through causal localization is not a property of QM, but results from the omnipresent vacuum polarization in QFT and does not require a Gibbs type ensemble avaraging (coupling to a heat bath).Comment: 10 pages, based on talk given at the 2002 Londrina Winter Schoo

    Backgrounding calves part 1 : assessing the opportunity (1993)

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    Backgrounding is the growing of steers and heifers from weaning until they enter the feedlot for finishing. It is suited to farmers who do not want to maintain a cow herd, do not want to finish cattle, but do want to put added weight on calves after weaning

    Backgrounding calves part 2 : herd health and feeding (1993)

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    Backgrounding calves, or taking weaned calves at about 450 pounds and feeding them up to 750 pounds or so, is becoming more popular among cattle producers. It can be a profit maker for the producer who wants an alternative to the cow/calf business, wants to use excess forage or other roughages, has extra time during parts of the year, or wants to add flexibility to his current cattle operation

    Backgrounding calves. Part 2. Herd health and feeding

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    "In Part 1 of this Agricultural Guide (number 2095) we discussed basic backgrounding strategies and compared profitability with other cattle enterprises. In this section, we will focus on herd health requirements and feeding for successful backgrounding. There are many animal health problems to consider, especially if you will be purchasing most or all of the calves to be backgrounded."--First page.Homer B. Sewell (Department of Animal Sciences), Victor E. Jacobs (Department of Agricultural Economics), and James R. Gerrish (Department of Agronomy)New 12/88/5

    Backgrounding calves

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    "Backgrounding is the growing of steers and heifers from weaning until they enter the feedlot for finishing. It is suited to farmers who do not want to maintain a cow herd, do not want to finish cattle but do want to put added weight on calves after weaning."--First page.Homer B. Sewell (Department of Animal Sciences), Victor E. Jacobs (Department of Agricultural Economics), James R. Gerrish (Department of Agronomy)New 12/88/5

    Growth, processing, and optical properties of epitaxial Er_2O_3 on silicon

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    Erbium-doped materials have been investigated for generating and amplifying light in low-power chip-scale optical networks on silicon, but several effects limit their performance in dense microphotonic applications. Stoichiometric ionic crystals are a potential alternative that achieve an Er^(3+) density 100× greater. We report the growth, processing, material characterization, and optical properties of single-crystal Er_2O_3 epitaxially grown on silicon. A peak Er^(3+) resonant absorption of 364 dB/cm at 1535nm with minimal background loss places a high limit on potential gain. Using high-quality microdisk resonators, we conduct thorough C/L-band radiative efficiency and lifetime measurements and observe strong upconverted luminescence near 550 and 670 nm

    Full abstraction for fair testing in CCS

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    In previous work with Pous, we defined a semantics for CCS which may both be viewed as an innocent presheaf semantics and as a concurrent game semantics. It is here proved that a behavioural equivalence induced by this semantics on CCS processes is fully abstract for fair testing equivalence. The proof relies on a new algebraic notion called playground, which represents the 'rule of the game'. From any playground, two languages, equipped with labelled transition systems, are derived, as well as a strong, functional bisimulation between them.Comment: 15 pages, to appear in CALCO '13. To appear Lecture notes in computer science (2013

    Quantum macrostatistical picture of nonequilibrium steady states

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    We employ a quantum macrostatistical treatment of irreversible processes to prove that, in nonequilibrium steady states, (a) the hydrodynamical observables execute a generalised Onsager-Machlup process and (b) the spatial correlations of these observables are generically of long range. The key assumptions behind these results are a nonequilibrium version of Onsager's regression hypothesis, together with certain hypotheses of chaoticity and local equilibrium for hydrodynamical fluctuations.Comment: TeX, 13 page
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