318,494 research outputs found

    Calderon-Type Uniqueness Theorem for Stochastic Partial Differential Equations

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    In this Note, we present a Calder\'on-type uniqueness theorem on the Cauchy problem of stochastic partial differential equations. To this aim, we introduce the concept of stochastic pseudo-differential operators, and establish their boundedness and other fundamental properties. The proof of our uniqueness theorem is based on a new Carleman-type estimate.Comment:

    Extended phase space thermodynamics for third order Lovelock black holes in diverse dimensions

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    Treating the cosmological constant as thermodynamic pressure and its conjugate as thermodynamic volume, we investigate the critical behavior of the third order Lovelock black holes in diverse dimensions. For black hole horizons with different normalized sectional curvature k=0,±1k=0,\pm1, the corresponding critical behaviors differ drastically. For k=0k=0, there is no critical point in the extended thermodynamic phase space. For k=1k=-1, there is a single critical point in any dimension d7d\geq 7, and for k=+1k=+1, there is a single critical point in 77 dimension and two critical points in 8,9,10,118,9,10,11 dimensions. We studied the corresponding phase structures in all possible cases.Comment: pdflatex, 22 pages, 36 eps figures included. V2: minor corrections and new reference

    Coupling tunable D-band directional coupler for millimeter-wave applications

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    A coupling tunable D-band directional coupler is designed based on a novel coupling grid structure proposed in this letter. The designed directional coupler has excellent performance with ultra-wideband. The coupling can be tuned from -28.2 dB to -33.2 dB at 140 GHz by changing the angle of the coupling grid, and the dynamic range of the coupling is about 5 dB. The return loss is smaller than -15 dB in the whole D-band from 110 GHz to 170 GHz. A 3-dB coupler use the similar coupling structure is also designed. The coupling is 3.3144 dB at the center frequency of 140 GHz.Comment: 2 pages, 6figure

    Gauss-Bonnet coupling constant as a free thermodynamical variable and the associated criticality

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    The thermodynamic phase space of Gauss-Bonnet (GB) AdS black holes is extended, taking the inverse of the GB coupling constant as a new thermodynamic pressure PGBP_{\mathrm{GB}}. We studied the critical behavior associated with PGBP_{\mathrm{GB}} in the extended thermodynamic phase space at fixed cosmological constant and electric charge. The result shows that when the black holes are neutral, the associated critical points can only exist in five dimensional GB-AdS black holes with spherical topology, and the corresponding critical exponents are identical to those for Van der Waals system. For charged GB-AdS black holes, it is shown that there can be only one critical point in five dimensions (for black holes with either spherical or hyperbolic topologies), which also requires the electric charge to be bounded within some appropriate range; while in d>5d>5 dimensions, there can be up to two different critical points at the same electric charge, and the phase transition can occur only at temperatures which are not in between the two critical values.Comment: 23 pages. V2: modified all P_{GB}-r_+ plots using dimensionless variables, added comments on the relationship to Einstein limi
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