9,394 research outputs found

    Special values of derivatives of LL-series and generalized Stieltjes constants

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    The connection between derivatives of L(s,f)L(s,f) for periodic arithmetical functions ff at s=1s=1 and generalized Stieltjes constants has been noted earlier. In this paper, we utilize this link to throw light on the arithmetic nature of L(1,f)L'(1,f) and certain Stieltjes constants. In particular, if pp is an odd prime greater than 77, then we deduce the transcendence of at least (p7)/2(p-7)/2 of the generalized Stieltjes constants, {γ1(a,p):1a<p}\{ \gamma_1(a,p) : 1 \leq a < p \}, conditional on a conjecture of S. Gun, M. R. Murty and P. Rath.Comment: 11 page

    On the production mechanism of radio-pulses from large extensive air showers

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    None of the theories put forward so far to explain the radio emission from cosmic ray showers, has been successful in giving a satisfactory explanation for all the experimental data obtained from various laboratories over the globe. It is apprehended that emission mechanism at low and high frequencies may be quite different. This calls for new theoretical look into the phenomenon. Theoretical as well as the experimental results indicate that the frequency spectrum is rather flat in the frequency range (40 to 60 MHz. Above 80 MHz, the radio emission can be explained with the help of geomagnetic mechanism. But at very low frequency ( 10 MHz), mechanisms other than geomagnetic are involved

    Effects on Amorphous Silicon Photovoltaic Performance from High-temperature Annealing Pulses in Photovoltaic Thermal Hybrid Devices

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    There is a renewed interest in photovoltaic solar thermal (PVT) hybrid systems, which harvest solar energy for heat and electricity. Typically, a main focus of a PVT system is to cool the photovoltaic (PV) cells to improve the electrical performance, however, this causes the thermal component to under-perform compared to a solar thermal collector. The low temperature coefficients of amorphous silicon (a-Si:H) allow for the PV cells to be operated at higher temperatures and are a potential candidate for a more symbiotic PVT system. The fundamental challenge of a-Si:H PV is light-induced degradation known as the Staebler-Wronski effect (SWE). Fortunately, SWE is reversible and the a-Si:H PV efficiency can be returned to its initial state if the cell is annealed. Thus an opportunity exists to deposit a-Si:H directly on the solar thermal absorber plate where the cells could reach the high temperatures required for annealing. In this study, this opportunity is explored experimentally. First a-Si:H PV cells were annealed for 1 hour at 100\degreeC on a 12 hour cycle and for the remaining time the cells were degraded at 50\degreeC in order to simulate stagnation of a PVT system for 1 hour once a day. It was found that, when comparing the cells after stabilization at normal 50\degreeC degradation, this annealing sequence resulted in a 10.6% energy gain when compared to a cell that was only degraded at 50\degreeC

    Non-destructive Orthonormal State Discrimination

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    We provide explicit quantum circuits for the non-destructive deterministic discrimination of Bell states in the Hilbert space CdnC^{d^{n}}, where dd is qudit dimension. We discuss a method for generalizing this to non-destructive measurements on any set of orthogonal states distributed among nn parties. From the practical viewpoint, we show that such non-destructive measurements can help lower quantum communication complexity under certain conditions.Comment: 11 pages, 6 fugure

    Dynamics of interacting quintessence

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    In this paper, we investigate coupled quintessence with scaling potential assuming specific forms of the coupling as AA namely, αρm˙\alpha \dot{\rho_m}, βρϕ˙\beta \dot{\rho_{\phi}} and σ(ρm˙+ρϕ˙)\sigma (\dot{\rho_m}+\dot{\rho_{\phi}}), and present phase space analysis for three different interacting models. We focus on the attractor solutions that can give rise to late time acceleration with ΩDE/ΩDM\Omega_{DE}/\Omega_{DM} of order unity in order to alleviate the coincidence problem.Comment: 11 pages, 3 figures, matches with the published versio
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