10,788 research outputs found
Excited Field of Particle in Quantum Theory
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
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
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
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
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
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
Dynamic radiation force of a pulsed Gaussian beam acting on a Rayleigh dielectric sphere
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
The Ages of M31 Star Clusters: Spectral Energy Distribution Versus Color-Magnitude Diagram
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 bands, as well as the Wide-field Infrared
Survey Explorer ({\sl WISE}) / 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} / 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
Stability for the inverse source problems in elastic and electromagnetic waves
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
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 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 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 and weighted oscillator strengths 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 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 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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