6,286 research outputs found
Stability of linear and non-linear lambda and tripod systems in the presence of amplitude damping
We present the stability analysis of the dark states in the adiabatic passage
for the linear and non-linear lambda and tripod systems in the presence of
amplitude damping (losses). We perform an analytic evaluation of the real parts
of eigenvalues of the corresponding Jacobians, the non-zero eigenvalues of
which are found from the quadratic characteristic equations, as well as by the
corresponding numerical simulations. For non-linear systems, we evaluate the
Jacobians at the dark states. Similarly to the linear systems, here we also
find the non-zero eigenvalues from the characteristic quadratic equations. We
reveal a common property of all the considered systems showing that the
evolution of the real parts of eigenvalues can be split into three stages. In
each of them the evolution of the stimulated Raman adiabatic passage (STIRAP)
is characterized by different effective dimension. This results in a possible
adiabatic reduction of one or two degrees of freedom.Comment: 30 pages, 12 figure
In-orbit demonstration of X-ray pulsar navigation with the Insight-HXMT satellite
In this work, we report the in-orbit demonstration of X-ray pulsar navigation
with Insight-Hard X-ray Modulation Telescope (Insight-HXMT), which was launched
on Jun. 15th, 2017. The new pulsar navigation method 'Significance Enhancement
of Pulse-profile with Orbit-dynamics' (SEPO) is adopted to determine the orbit
with observations of only one pulsar. In this test, the Crab pulsar is chosen
and observed by Insight-HXMT from Aug. 31th to Sept. 5th in 2017. Using the
5-day-long observation data, the orbit of Insight-HXMT is determined
successfully with the three telescopes onboard - High Energy X-ray Telescope
(HE), Medium Energy X-ray Telescope (ME) and Low Energy X-ray Telescope (LE) -
respectively. Combining all the data, the position and velocity of the
Insight-HXMT are pinpointed to within 10 km (3 sigma) and 10 m/s (3 sigma),
respectively.Comment: Accepted by the Astrophysical Journal Supplemen
Identification of an intraocular microbiota
The current dogma in ophthalmology and vision research presumes the intraocular environment to be sterile. However, recent evidence of intestinal bacterial translocation into the bloodstream and many other internal organs including the eyes, found in healthy and diseased animal models, suggests that the intraocular cavity may also be inhabited by a microbial community. Here, we tested intraocular samples from over 1000 human eyes. Using quantitative PCR, negative staining transmission electron microscopy, direct culture, and high-throughput sequencing technologies, we demonstrated the presence of intraocular bacteria. The possibility that the microbiome from these low-biomass communities could be a contamination from other tissues and reagents was carefully evaluated and excluded. We also provide preliminary evidence that a disease-specific microbial signature characterized the intraocular environment of patients with age-related macular degeneration and glaucoma, suggesting that either spontaneous or pathogenic bacterial translocation may be associated with these common sight-threatening conditions. Furthermore, we revealed the presence of an intraocular microbiome in normal eyes from non-human mammals and demonstrated that this varied across species (rat, rabbit, pig, and macaque) and was established after birth. These findings represent the first-ever evidence of intraocular microbiota in humans
Discovery of delayed spin-up behavior following two large glitches in the Crab pulsar, and the statistics of such processes
Glitches correspond to sudden jumps of rotation frequency () and its
derivative () of pulsars, the origin of which remains not well
understood yet, partly because the jump processes of most glitches are not well
time-resolved. There are three large glitches of the Crab pulsar, detected in
1989, 1996 and 2017, which were found to have delayed spin-up processes before
the normal recovery processes. Here we report two additional glitches of the
Crab pulsar occurred in 2004 and 2011 for which we discovered delayed spin up
processes, and present refined parameters of the largest glitch occurred in
2017. The initial rising time of the glitch is determined as hour. We
also carried out a statistical study of these five glitches with observed
spin-up processes. The two glitches occurred in 2004 and 2011 have delayed
spin-up time scales () of \,days and \,days,
respectively. We find that the vs. relation
of these five glitches is similar to those with no detected delayed spin-up
process, indicating that they are similar to the others in nature except that
they have larger amplitudes. For these five glitches, the amplitudes of the
delayed spin-up process () and recovery process
(), their time scales (, ), and
permanent changes in spin frequency () and total frequency
step () have positive correlations. From these
correlations, we suggest that the delayed spin-up processes are common for all
glitches, but are too short and thus difficult to be detected for most
glitches.Comment: 25 pages, 8 figure
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