6,024 research outputs found

    Alignments of parity even/odd-only multipoles in CMB

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    We compare the statistics of parity even and odd multipoles of the cosmic microwave background (CMB) sky from PLANCK full mission temperature measurements. An excess power in odd multipoles compared to even multipoles has previously been found on large angular scales. Motivated by this apparent parity asymmetry, we evaluate directional statistics associated with even compared to odd multipoles, along with their significances. Primary tools are the \emph{Power Tensor} and \emph{Alignment Tensor} statistics. We limit our analysis to the first sixty multipoles i.e., l=[2,61]l=[2,61]. We find no evidence for statistically unusual alignments of even parity multipoles. More than one independent statistic finds evidence for alignments of anisotropy axes of odd multipoles, with a significance equivalent to 2σ\sim 2 \sigma or more. The robustness of alignment axes is tested by making galactic cuts and varying the multipole range. Very interestingly, the region spanned by the (a)symmetry axes is found to broadly contain other parity (a)symmetry axes previously observed in the literature.Comment: 13 pages, 13 figures, Matches the version accepted in MNRA

    Numerical approach for retention characteristics of double floating-gate memories

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    We report on a numerical investigation in which memory characteristics of double floating-gate (DFG) structure were compared to those of the conventional single floating-gate structure, including an interference effect between two cells. We found that the advantage of the DFG structure is its longer retention time and the disadvantage is its smaller threshold voltage shift. We also provide an analytical form of charging energy including the interference effect.Comment: 4 pages, 4 figure

    (Anti-)Symmetrizing Wave Functions

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    The construction of fully (anti-)symmetric states with many particles, when the single particle state carries multiple quantum numbers, is a problem that seems to have not been systematically addressed in the literature. A quintessential example is the construction of ground state baryon wave functions where the color singlet condition reduces the problem to just two (flavor and spin) quantum numbers. In this paper, we address the general problem by noting that it can be re-interpreted as an eigenvalue equation, and provide a formalism that applies to generic number of particles and generic number of quantum numbers. As an immediate result, we find a complete solution to the two quantum number case, from which the baryon wave function problem with arbitrary number of flavors follows. As a more elaborate illustration that reveals complications not visible in the two quantum number case, we present the complete class of states possible for a system of five fermionic particles with three quantum numbers each. Our formalism makes systematic use of properties of the symmetric group and Young tableaux. Even though our motivations to consider this question have their roots in SYK-like tensor models and holography, the problem and its solution should have broader applications.Comment: v3: journal version, contains slightly expanded discussions and example

    HESS J1632-478: an energetic relic

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    HESS J1632-478 is an extended and still unidentified TeV source in the galactic plane. In order to identify the source of the very high energy emission and to constrain its spectral energy distribution, we used a deep observation of the field obtained with XMM-Newton together with data from Molonglo, Spitzer and Fermi to detect counterparts at other wavelengths. The flux density emitted by HESS J1632-478 peaks at very high energies and is more than 20 times weaker at all other wavelengths probed. The source spectrum features two large prominent bumps with the synchrotron emission peaking in the ultraviolet and the external inverse Compton emission peaking in the TeV. HESS J1632-478 is an energetic pulsar wind nebula with an age of the order of 10^4 years. Its bolometric (mostly GeV-TeV) luminosity reaches 10% of the current pulsar spin down power. The synchrotron nebula has a size of 1 pc and contains an unresolved point-like X-ray source, probably the pulsar with its wind termination shock.Comment: A&A accepted, 9 pages, 5 figures, 4 table

    Krill: An exploration in underwater sensor networks

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    While sensor networks have now become very popular on land, the underwater environment still poses some difficult problems. Communication is one of the difficult challenges under water. There are two options: optical and acoustic. We have designed an optical communication board that allows the Fleck’s to communicate optically. We have tested the resulting underwater sensor nodes in two different applications

    Time stamped Digital Signature Scheme with Message Recovery & Its Application in E-Cash System

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    We propose a Timestamped signature scheme which can be verified universally using signer’s public parameters. A trusted third party, the Timestamping System provides timestamp to a signature without even knowing the content of the document. The proposed scheme can withstand active attacks, such as forgery attack and chosen cipher text attack. It also provides the message recovery feature, i.e., from the timestamped signature, the message can be recovered by the receiver. Hence, the message need not be sent with the signature. The suggested scheme do not require any hash function and there by reduces the verification cost as compared to existing schemes at the expense of marginal increase in signature generation cost. Further, the scheme is more secured as its security lies in solving three computationally hard assumptions Performance analysis of both the schemes has been carried out in details. We applied the Time-stamped signature scheme with Message recovery in Ecash syste

    The Contribution of the Light Quark Condensate to the Pion-Nucleon Sigma Term

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    There has been a discrepancy between values of the pion-nucleon sigma term extracted by two different methods for many years. Analysis of recent high precision pion-nucleon data has widened the gap between the two determinations. It is argued that the two extractions correspond to different quantities and that the difference between them can be understood and calculated.Comment: Modern Physics Letters A (in press
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