4,189 research outputs found
Interaction Between Supernova Remnant G22.7-0.2 And The Ambient Molecular Clouds
We have carried out 12CO (J=1-0 and 2-1), 13CO (J=1-0), and C18O (J=1-0)
observations in the direction of the supernova remnant (SNR) G22.7-0.2. A
filamentary molecular gas structure, which is likely part of a larger molecular
complex with VLSR~75-79 km/s, is detected and is found to surround the southern
boundary of the remnant. In particular, the high-velocity wing (77-110 km/s) in
the 12CO (J=1-0 and J=2-1) emission shows convincing evidence of the
interaction between SNR G22.7-0.2 and the 75-79 km/s molecular clouds (MCs).
Spectra with redshifted profiles, a signature of shocked molecular gas, are
seen in the southeastern boundary of the remnant. The association between the
remnant and the 77 km/s MCs places the remnant at the near distance of 4.0-4.8
kpc, which agrees with a location on the Scutum-Crux arm. We suggest that SNR
G22.7-0.2, SNR W41, and HII region G022.760-0.485 are at the same distance and
are associated with GMC G23.0-0.4.Comment: 9 pages, 9 figures, 3 tables, accepted for publication in Ap
Spectral and optical properties in the antiphase stripe phase of the cuprate superconductors
We investigate the superconducting order parameter, the spectral and optical
properties in a stripe model with spin (charge) domain-derived scattering
potential (). We show that the charge domain-derived scattering
is less effective than the spin scattering on the suppression of
superconductivity. For , the spectral weight concentrates on
the () antinodal region, and a finite energy peak appears in the optical
conductivity with the disappearance of the Drude peak. But for , the spectral weight concentrates on the () nodal region,
and a residual Drude peak exists in the optical conductivity without the finite
energy peak. These results consistently account for the divergent observations
in the ARPES and optical conductivity experiments in several high-
cuprates, and suggest that the "insulating" and "metallic" properties are
intrinsic to the stripe state, depending on the relative strength of the spin
and charge domain-derived scattering potentials.Comment: 7 pages, 4 figure
Coexistence of the antiferromagnetic and superconducting order and its effect on spin dynamics in electron-doped high- cuprates
In the framework of the slave-boson approach to the model, it is
found that for electron-doped high- cuprates, the staggered
antiferromagnetic (AF) order coexists with superconducting (SC) order in a wide
doping level ranged from underdoped to nearly optimal doping at the mean-field
level. In the coexisting phase, it is revealed that the spin response is
commensurate in a substantial frequency range below a crossover frequency
for all dopings considered, and it switches to the incommensurate
structure when the frequency is higher than . This result is in
agreement with the experimental measurements. Comparison of the spin response
between the coexisting phase and the pure SC phase with a
-wave pairing plus a higher harmonics term (DP+HH) suggests
that the inclusion of the two-band effect is important to consistently account
for both the dispersion of the spin response and the non-monotonic gap behavior
in the electron-doped cuprates.Comment: 6 pages, 5 figure
Self-organization and phase transition in financial markets with multiple choices
Market confidence is essential for successful investing. By incorporating
multi-market into the evolutionary minority game, we investigate the effects of
investor beliefs on the evolution of collective behaviors and asset prices.
When there exists another investment opportunity, market confidence, including
overconfidence and under-confidence, is not always good or bad for investment.
The roles of market confidence is closely related to market impact. For low
market impact, overconfidence in a particular asset makes an investor become
insensitive to losses and a delayed strategy adjustment leads to a decline in
wealth, and thereafter, one's runaway from the market. For high market impact,
under-confidence in a particular asset makes an investor over-sensitive to
losses and one's too frequent strategy adjustment leads to a large fluctuation
in asset prices, and thereafter, a decrease in the number of agents. At an
intermediate market impact, the phase transition occurs. No matter what the
market impact is, an equilibrium between different markets exists, which is
reflected in the occurrence of similar price fluctuations in different markets.
A theoretical analysis indicates that such an equilibrium results from the
coupled effects of strategy updating and shift in investment. The runaway of
the agents trading a specific asset will lead to a decline in the asset price
volatility and such a decline will be inhibited by the clustering of the
strategies. A uniform strategy distribution will lead to a large fluctuation in
asset prices and such a fluctuation will be suppressed by the decrease in the
number of agents in the market. A functional relationship between the price
fluctuations and the numbers of agents is found
Topological Dirac states beyond orbitals for silicene on SiC(0001) surface
The discovery of intriguing properties related to the Dirac states in
graphene has spurred huge interest in exploring its two-dimensional group-IV
counterparts, such as silicene, germanene, and stanene. However, these
materials have to be obtained via synthesizing on substrates with strong
interfacial interactions, which usually destroy their intrinsic
()-orbital Dirac states. Here we report a theoretical study on the
existence of Dirac states arising from the orbitals instead of
orbitals in silicene on 4H-SiC(0001), which survive in spite of the strong
interfacial interactions. We also show that the exchange field together with
the spin-orbital coupling give rise to a detectable band gap of 1.3 meV. Berry
curvature calculations demonstrate the nontrivial topological nature of such
Dirac states with a Chern number , presenting the potential of realizing
quantum anomalous Hall effect for silicene on SiC(0001). Finally, we construct
a minimal effective model to capture the low-energy physics of this system.
This finding is expected to be also applicable to germanene and stanene, and
imply great application potentials in nanoelectronics.Comment: 6 Figures , Accepted by Nano Letter
Revisiting the distance, environment and supernova properties of SNR G57.2+0.8 that hosts SGR 1935+2154
We have performed a multi-wavelength study of supernova remnant (SNR)
G57.2+0.8 and its environment. The SNR hosts the magnetar SGR 1935+2154, which
emitted an extremely bright ms-duration radio burst on 2020 Apr 28 (The
Chime/Frb Collaboration et al. 2020; Bochenek et al. 2020). We used the 12CO
and 13CO J=1-0 data from the Milky Way Image Scroll Painting (MWISP) CO line
survey to search for molecular gas associated with G57.2+0.8, in order to
constrain the physical parameters (e.g., the distance) of the SNR and its
magnetar. We report that SNR G57.2+0.8 is likely impacting the molecular clouds
(MCs) at the local standard of rest (LSR) velocity V_{LSR} ~ 30 km/s and
excites a weak 1720 MHz OH maser with a peak flux density of 47 mJy/beam. The
chance coincidence of a random OH spot falling in the SNR is <12%, and the
OH-CO correspondence chance is 7% at the maser spot. This combines to give < 1%
false probability of the OH maser, suggesting a real maser detection. The LSR
velocity of the MCs places the SNR and magnetar at a kinematic distance of
d=6.6 +/- 0.7 kpc. The nondetection of thermal X-ray emission from the SNR and
the relatively dense environment suggests G57.2+0.8 be an evolved SNR with an
age (d/6.6 kpc) yr. The explosion energy of G57.2+0.8 is
lower than erg,
which is not very energetic even assuming a high ambient density = 10
cm. This reinforces the opinion that magnetars do not necessarily result
from very energetic supernova explosions.Comment: 9 pages, 5 figures, accepted for publication in the Astrophysical
Journa
Editorial: Unravelling Copper-Regulatory Systems and Copper-Affected Pathways in Cancer Cells to Improve Current Therapies
Unravelling Copper-Regulatory Systems and Copper-Affected Pathways in Cancer Cells to Improve Current Therapie
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