34,991 research outputs found

    EFFECT OF RACCOON (PROCYON LOTOR) REDUCTION ON BLANDING’S TURTLE (EMYDOIDEA BLANDINGII) NEST SUCCESS

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    The Lake County Forest Preserve District has monitored a state-endangered Blanding’s Turtle (Emydoidea blandingii) population at two adjoining nature preserves along the Illinois–Wisconsin border since 2004. Prior to predator management, 92.3% of documented and unprotected natural Blanding’s Turtle nests (12 of 13) and 88% of monitored artificial nests have been at least partially depredated. The goal of this study was to determine the efficacy of subsidized Raccoon (Procyon lotor) removal efforts in increasing the nest success of Blanding’s Turtles. During April–May 2013 and 2014, we captured and euthanized 78 Raccoons from our 2 km2 study area. We estimated pre-removal abundance estimates using the Leslie depletion method; it appeared that we removed 83–89% of the Raccoons from the study area each year and pre-removal density estimates were 37.5% lower in 2014 than 2013. During the study period, we monitored 22 Blanding’s Turtle in situ unprotected nests. In 2013, one of seven (14%) Blanding’s Turtle nests was partially depredated and no nests were completely depredated, indicative of a successful impact of Raccoon removal on Blanding’s Turtle nest success. However in 2014, nine of 15 (60%) Blanding’s Turtle nests were depredated. Our results provide some evidence that removal of Raccoons may have increased Blanding’s Turtle nest success but other factors, such as a functional response of surviving Raccoons or depredation by other subsidized predators may be contributing to decreased nest success

    Entanglement versus mixedness for coupled qubits under a phase damping channel

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    Quantification of entanglement against mixing is given for a system of coupled qubits under a phase damping channel. A family of pure initial joint states is defined, ranging from pure separable states to maximally entangled state. An ordering of entanglement measures is given for well defined initial state amount of entanglement.Comment: 9 pages, 2 figures. Replaced with final published versio

    Analysis of a convenient information bound for general quantum channels

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    Open questions from Sarovar and Milburn (2006 J.Phys. A: Math. Gen. 39 8487) are answered. Sarovar and Milburn derived a convenient upper bound for the Fisher information of a one-parameter quantum channel. They showed that for quasi-classical models their bound is achievable and they gave a necessary and sufficient condition for positive operator-valued measures (POVMs) attaining this bound. They asked (i) whether their bound is attainable more generally, (ii) whether explicit expressions for optimal POVMs can be derived from the attainability condition. We show that the symmetric logarithmic derivative (SLD) quantum information is less than or equal to the SM bound, i.e.\ H(Ξ)≀C΄(Ξ)H(\theta) \leq C_{\Upsilon}(\theta) and we find conditions for equality. As the Fisher information is less than or equal to the SLD quantum information, i.e. FM(Ξ)≀H(Ξ)F_M(\theta) \leq H(\theta), we can deduce when equality holds in FM(Ξ)≀C΄(Ξ)F_M(\theta) \leq C_{\Upsilon}(\theta). Equality does not hold for all channels. As a consequence, the attainability condition cannot be used to test for optimal POVMs for all channels. These results are extended to multi-parameter channels.Comment: 16 pages. Published version. Some of the lemmas have been corrected. New resuts have been added. Proofs are more rigorou

    Directly estimating non-classicality

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    We establish a method of directly measuring and estimating non-classicality - operationally defined in terms of the distinguishability of a given state from one with a positive Wigner function. It allows to certify non-classicality, based on possibly much fewer measurement settings than necessary for obtaining complete tomographic knowledge, and is at the same time equipped with a full certificate. We find that even from measuring two conjugate variables alone, one may infer the non-classicality of quantum mechanical modes. This method also provides a practical tool to eventually certify such features in mechanical degrees of freedom in opto-mechanics. The proof of the result is based on Bochner's theorem characterizing classical and quantum characteristic functions and on semi-definite programming. In this joint theoretical-experimental work we present data from experimental optical Fock state preparation, demonstrating the functioning of the approach.Comment: 4+1 pages, 2 figures, minor change

    Error correction in ensemble registers for quantum repeaters and quantum computers

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    We propose to use a collective excitation blockade mechanism to identify errors that occur due to disturbances of single atoms in ensemble quantum registers where qubits are stored in the collective population of different internal atomic states. A simple error correction procedure and a simple decoherence-free encoding of ensemble qubits in the hyperfine states of alkali atoms are presented.Comment: 4 pages, 2 figure

    Study of the D∗ρD^*\rho system using QCD sum rules

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    In this talk I present a study of the D∗ρD^* \rho system made by using the method of QCD sum rules. Considering isospin and spin projectors, we investigate the different configurations and obtain three D∗D^* mesons with isospin I=1/2I=1/2, spin S=0S=0, 11, 22 and with masses 2500±672500\pm 67 MeV, 2523±602523\pm60 MeV, and 2439±1192439\pm119 MeV, respectively. The last state can be related to D2∗(2460)D^*_2(2460) (spin 2) listed by the Particle Data Group, while one of the first two might be associated with D∗(2640)D^*(2640), whose spin-parity is unknown. In the case of I=3/2I=3/2 we also find evidences of three states with spin 0, 1 and 2, respectively, with masses 2467±822467\pm82 MeV, 2420±1282420\pm128 MeV, and 2550±562550\pm56 MeV.Comment: Contribution to the proceedings of the XXXVI Reuni\~ao de Trabalho sobre F\'isica Nuclear no Brasil, Maresias, S\~ao Paulo, Brazi

    Quantum state engineering, purification, and number resolved photon detection with high finesse optical cavities

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    We propose and analyze a multi-functional setup consisting of high finesse optical cavities, beam splitters, and phase shifters. The basic scheme projects arbitrary photonic two-mode input states onto the subspace spanned by the product of Fock states |n>|n> with n=0,1,2,.... This protocol does not only provide the possibility to conditionally generate highly entangled photon number states as resource for quantum information protocols but also allows one to test and hence purify this type of quantum states in a communication scenario, which is of great practical importance. The scheme is especially attractive as a generalization to many modes allows for distribution and purification of entanglement in networks. In an alternative working mode, the setup allows of quantum non demolition number resolved photodetection in the optical domain.Comment: 14 pages, 10 figure
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