8,311 research outputs found
Dynamical System of Scalar Field from 2-Dimension to 3-D and its Cosmological Implication
We give the three-dimensional dynamical autonomous systems for most of the
popular scalar field dark energy models including (phantom) quintessence,
(phantom) tachyon, k-essence and general non-canonical scalar field models,
change the dynamical variables from variables to observable
related variables , and show the intimate
relationships between those scalar fields that the three-dimensional system of
k-essence can reduce to (phantom) tachyon, general non-canonical scalar field
can reduce to (phantom) quintessence and k-essence can also reduce to (phantom)
quintessence for some special cases. For the applications of the
three-dimensional dynamical systems, we investigate several special cases and
give the exactly dynamical solutions in detail. In the end of this paper, we
argue that, it is more convenient and also has more physical meaning to express
the differential equations of dynamical systems in instead of variables and to investigate the
dynamical system in 3-Dimension instead of 2-Dimension. We also raise a
question about the possibility of the chaotic behavior in the spatially flat
single scalar field FRW cosmological models in the presence of ordinary matter.Comment: 20 pages, 8 figures,some references added. Minor changes according to
the suggestions from referee
A simple and natural interpretations of the DAMPE cosmic-ray electron/positron spectrum within two sigma deviations
The DArk Matter Particle Explorer (DAMPE) experiment has recently announced
the first results for the measurement of total electron plus positron fluxes
between 25 GeV and 4.6 TeV. A spectral break at about 0.9 TeV and a tentative
peak excess around 1.4 TeV have been found. However, it is very difficult to
reproduce both the peak signal and the smooth background including spectral
break simultaneously. We point out that the numbers of events in the two energy
ranges (bins) close to the 1.4 TeV excess have deficits. With the
basic physics principles such as simplicity and naturalness, we consider the
, , and deviations due to statistical
fluctuations for the 1229.3~GeV bin, 1411.4~GeV bin, and 1620.5~GeV bin.
Interestingly, we show that all the DAMPE data can be explained consistently
via both the continuous distributed pulsar and dark matter interpretations,
which have and (for all the 38
points in DAMPE electron/positron spectrum with 3 of them revised),
respectively. These results are different from the previous analyses by
neglecting the 1.4 TeV excess. At the same time, we do a similar global fitting
on the newly released CALET lepton data, which could also be interpreted by
such configurations. Moreover, we present a dark matter model with
Breit-Wigner mechanism, which can provide the proper dark matter annihilation
cross section and escape the CMB constraint. Furthermore, we suggest a few ways
to test our proposal.Comment: 18 pages, 6 figures, 5 tables. Figures and Bibs update
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