10,436 research outputs found

    Excited Field of Particle in Quantum Theory

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    A model about excited field of a particle is discussed. We found this model will give wave-particle duality clearly and its Lagrangian is consistent with Quantum Theory. A new interpretation of quantum mechanics but not statistical interpretation[1] is presented.Comment: 9 page

    A Model of Quantum Field Theory with Inter Source

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    By putting a confined inter source, we construct a model which can give us convergent solution from free field equation. On the other hand, the solution of new field equation can be separated into two parts, one part is just same as the one in Quantum Field Theory and make it survived in this model, and the other part, which we will see doesn't take energy and momentum, just gives us a negative propagator which can soften quadratic divergence.Comment: 6 pages, RevTe

    D rare/forbidden decays at BESIII

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    In this document we present the latest result on rare/forbidden decays for D mesons at the BESIII experiment. Based on 2.92/fb data taken at the center-of-mass energy 3.773 GeV with the BESIII detector, the flavor-changing neutral current process of neutral D decays into two gammas is searched using a double tag technique, while the decays of charged D decays into a charged kaon/pion plus two electrons/positrons are studied based on a single tag method. The resulting upper limits are still above the Standard Model predictions.Comment: To be published in the proceedings of CHARM-2015, Detroit, MI, 18-22 May 201

    The Milky Way's circular velocity curve and its constraint on the Galactic mass with RR Lyrae stars

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    We present a sample of 1148 ab-type RR Lyrae (RRLab) variables identified from Catalina Surveys Data Release 1, combined with SDSS DR8 and LAMOST DR4 spectral data. We firstly use a large sample of 860 Galactic halo RRLab stars and derive the circular velocity distributions for the stellar halo. With the precise distances and carefully determined radial velocities (the center-of-mass radial velocities) by considering the pulsation of the RRLab stars in our sample, we can obtain a reliable and comparable stellar halo circular velocity curve. We take two different prescriptions for the velocity anisotropy parameter {\beta} in the Jeans equation to study the circular velocity curve and mass profile. We test two different solar peculiar motions in our calculation. Our best result with the adopted solar peculiar motion 1 of (U, V, W) = (11.1, 12, 7.2) km/s is that the enclosed mass of the Milky Way within 50 kpc is (3.75 +/- 1.33) *10^11Msun based on \beta = 0 and the circular velocity 180 +/- 31.92 (km/s) at 50 kpc. This result is consistent with dynamical model results, and it is also comparable to the previous similar works.Comment: 20 pages, 8 figures, accepted by Ap

    Complexity/Action duality of shock wave geometry in a massive gravity theory

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    On the holographic complexity dual to the bulk action, we investigate the action growth for a shock wave geometry in a massive gravity theory within the Wheeler-De Witt (WDW) patch at the late time limit. For a global shock wave, the graviton mass does not affect the action growth in the bulk, i.e. the complexity on the boundary, showing that the action growth (complexity) is the same for both the Einstein gravity and the massive gravity. Nevertheless, for a local shock wave that depends on transverse coordinates, the action growth (complexity) is proportional to the butterfly velocity for the two gravity theories, but the butterfly velocity of the massive gravity theory is smaller than that of the Einstein gravity theory, indicating that the action growth (complexity) of the massive gravity is depressed by the graviton mass. In addition, we extend the black hole thermodynamics of the massive gravity and obtain the right Smarr formula.Comment: v1: 19 pages, 2 figures; v2: clarifications added, the final version to appear in Physical Review

    First- and Second-order Fermi Acceleration at Parallel Shocks

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    We report on a new Monte Carlo method for simulating diffusive shock acceleration (DSA) of solar energetic particles at upstream and downstream regions of quasi-parallel collisionless shock waves under the influence of self-generated turbulence. By way of example, we apply the model to a fast 1500 km \mathrm{s}^{-1} coronal mass ejection at ten solar radii. Results indicate that the maximum energies at outer corona are likely to be limited to few MeV, due to lack of suprathermal protons for appreciable wave growth, and insufficient time required acceleration. We find that the second-order Fermi acceleration, although being a too slow process to have a notable effect at the highest energies, significantly flattens energy spectra at low energy end. Simulations indicate that protons continue to damp waves efficiently several solar radii from the shock in the downstream region, which may be an important mechanism for heating suprathermals. Our simulations also suggest that models assuming a simple isotropic scattering are likely to predict too efficient acceleration.Comment: 16 pages, 10 color figure

    The Ages of M31 Star Clusters: Spectral Energy Distribution Versus Color-Magnitude Diagram

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    It is well-known that fitting the Color Magnitude Diagrams (CMDs) to the theoretical isochrones is the main method to determine star cluster ages. However, when the CMDs are not available, the Spectral Energy Distribution (SED)-fitting technique is the only other approach, although it suffers the age-metallicity-reddening degeneracy. In this work, we gather the ages, metallicities and masses of dozens of M31 star clusters from the CMD-fitting with HST images from the literatures for comparison. We check the reliability of the SED-fitting results with different models, i.e., Bruzual \& Charlot 2003 model (BC03), Galaxy Evolutionary Synthesis Models ({\sl GALEV}) and Advanced Stellar Population Synthesis (ASPS) for the simple stellar populations (SSPs) with single stars (ss)-SSP/binary star (bs)-SSPs models. The photometry bands includes the Galaxy Evolution Explorer {\sl GALEX} FUV/NUV bands, optical/near-infrared UBVRIJHKUBVRIJHK bands, as well as the Wide-field Infrared Survey Explorer ({\sl WISE}) W1W1/W2W2 bands. The comparisons show that the SED-fitting ages agree well with the CMD-fitting ages, either with the fixed metallicity or with the free metallicity for both the BC03 and the {\sl GALEV} model. However, for the ASPS models, it seems that SED-fitting results are systematic older than the CMD ages, especially for the ages log t <9.0 (yr). The fitting also shows that the {\sl GALEX} FUV/NUV-band are more important than the {\sl WISE} W1W1/W2W2 for constraining the ages, which confirms the previous findings. We also derived the masses of our sample star clusters from the BC03 and {\sl GALEV} models and it is found that the values agree well with that in the literature.Comment: 33 pages, 8 figures. Accepted for publication in A

    Dynamic radiation force of a pulsed Gaussian beam acting on a Rayleigh dielectric sphere

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    We investigate the dynamic evolution of the radiation forces produced by the pulsed Gaussian beams acting on a Rayleigh dielectric sphere. We derive the analytical expressions for the scattering force and all components of the ponderomotive force induced by the pulsed Gaussian beams. Our analysis shows that the radiation force, for both the transverse and longitudinal components, can be greatly enhanced as the pulse duration decreases. It is further found that for the pulse with long pulse duration, it can be used for the stable trapping and manipulating the particle, while for the pulse with short pulse duration it may be used for guiding and moving the small dielectric particle. Finally we discuss the stability conditions of the effective manipulating the particle by the pulsed beam.Comment: 6 pages,5 figures

    Stability for the inverse source problems in elastic and electromagnetic waves

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    This paper concerns the inverse source problems for the time-harmonic elastic and electromagnetic wave equations. The goal is to determine the external force and the electric current density from boundary measurements of the radiated wave field, respectively. The problems are challenging due to the ill-posedness and complex model systems. Uniqueness and stability are established for both of the inverse source problems. Based on either continuous or discrete multi-frequency data, a unified increasing stability theory is developed. The stability estimates consist of two parts: the Lipschitz type data discrepancy and the high frequency tail of the source functions. As the upper bound of frequencies increases, the latter decreases and thus becomes negligible. The increasing stability results reveal that ill-posedness of the inverse problems can be overcome by using multi-frequency data. The method is based on integral equations and analytical continuation, and requires the Dirichlet data only. The analysis employs asymptotic expansions of Green's tensors and the transparent boundary conditions by using the Dirichlet-to-Neumann maps. In addition, for the first time, the stability is established on the inverse source problems for both the Navier and Maxwell equations

    Electron impact collision strengths in Si IX, Si X and Si XI

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    Electron impact collision strengths among 560 levels of Si IX, 320 levels of Si X and 350 levels of Si XI have been calculated using the Flexible Atomic Code (FAC) of Gu (2003). Collision strengths Ω\Omega at ten scattered electron energies covering an entire energy range, namely 10, 50, 100, 200, 400, 600, 800, 1000, 1500 and 2000 eV, are reported. Assuming a Maxwellian energy distribution, effective collision strengths Υ\Upsilon are obtained at a finer electron temperature grids of 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 MK, which covers the typical temperature range of astrophysical hot plasma. Additionally, radiative rates AA and weighted oscillator strengths gfgf are given for more possible transitions among these levels. Comparisons of our results with available predictions reported in earlier literatures are made, and the accuracy of the data is assessed. Most transitions exhibit a better agreement, whereas large differences in gfgf appear for a few cases, which are due to the different inclusion of configuration interaction in different theoretical calculations. In excitations among levels of ground and lower excited configurations, large discrepancies of Υ\Upsilon maybe resulted from the consideration of resonance effects in earlier works.Comment: 42 pages, 7 figures, in press of Atom. Data and Nucl. Data Table
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