894 research outputs found
Scaling and non-Abelian signature in fractional quantum Hall quasiparticle tunneling amplitude
We study the scaling behavior in the tunneling amplitude when quasiparticles
tunnel along a straight path between the two edges of a fractional quantum Hall
annulus. Such scaling behavior originates from the propagation and tunneling of
charged quasielectrons and quasiholes in an effective field analysis. In the
limit when the annulus deforms continuously into a quasi-one-dimensional ring,
we conjecture the exact functional form of the tunneling amplitude for several
cases, which reproduces the numerical results in finite systems exactly. The
results for Abelian quasiparticle tunneling is consistent with the scaling
anaysis; this allows for the extraction of the conformal dimensions of the
quasiparticles. We analyze the scaling behavior of both Abelian and non-Abelian
quasiparticles in the Read-Rezayi Z_k-parafermion states. Interestingly, the
non-Abelian quasiparticle tunneling amplitudes exhibit nontrivial k-dependent
corrections to the scaling exponent.Comment: 16 pages, 4 figure
Two new species of centipedes, Tygarrup daliensis sp. nov. (Mecistocephalidae) and Australobius cangshanensis sp. nov. (Lithobiidae), from Southwestern China
Two new species of Chilopoda from Yunnan Province, China, are described as new: Tygarrup daliensis sp. nov. (Geophilomorpha, Mecistocephalidae) and Australobius cangshanensis sp. nov. (Lithobiomorpha, Lithobiidae). Tygarrup daliensis sp. nov. differs from other Tygarrup species by its each side of clypeal plagula with up to 15 se-tae, arranged in three irregular rows; labral posterior ala rough, with about 10 longitudinal slanting stripes near to mid-piece tooth; mandible with 9 pectinate dentate lamellae, 1st mandibular pectinate lamella bearing 6 teeth; each coxopleuron of last leg-bearing segments with about 50 pores of various size. Australobius cangshanensis sp. nov. is distinguished from congeners by a row of about 60 short setae transversely on each posterior part of 6th and 7th sternites; forcipular coxosternite with 7–10 coxosternal teeth, and porodonts between 5th and 6th or between 4th and 5th innermost teeth
An Algorithm for Preferential Selection of Spectroscopic Targets in LEGUE
We describe a general target selection algorithm that is applicable to any
survey in which the number of available candidates is much larger than the
number of objects to be observed. This routine aims to achieve a balance
between a smoothly-varying, well-understood selection function and the desire
to preferentially select certain types of targets. Some target-selection
examples are shown that illustrate different possibilities of emphasis
functions. Although it is generally applicable, the algorithm was developed
specifically for the LAMOST Experiment for Galactic Understanding and
Exploration (LEGUE) survey that will be carried out using the Chinese Guo Shou
Jing Telescope. In particular, this algorithm was designed for the portion of
LEGUE targeting the Galactic halo, in which we attempt to balance a variety of
science goals that require stars at fainter magnitudes than can be completely
sampled by LAMOST. This algorithm has been implemented for the halo portion of
the LAMOST pilot survey, which began in October 2011.Comment: 17 pages, 7 figures, accepted for publication in RA
Generation of heralded optical `Schroedinger cat' states by photon-addition
Optical "Schr\"odinger cat" states, the non-classical superposition of two
quasi-classical coherent states, serve as a basis for gedanken experiments
testing quantum physics on mesoscopic scales and are increasingly recognized as
a resource for quantum information processing. Here, we report the first
experimental realization of optical "Schr\"odinger cats" by adding a photon to
a squeezed vacuum state, so far only photon-subtraction protocols have been
realized. Photon-addition gives us the advantage of using heralded signal
photons as experimental triggers, and we can generate "Schr\"odinger cats" at
rates exceeding counts per second; at least one order of
magnitude higher than all previously reported realizations. Wigner
distributions with pronounced negative parts are demonstrated at down to -8.89
dB squeezing, even when the initial squeezed vacuum input state has low purity.
Benchmarking against such a degraded squeezed input state we report a maximum
fidelity of more than 80% with a maximum cat amplitude of . Our experiment uses photon-addition from pairs, one of those photons is
used for monitoring, giving us enhanced control; moreover the pair production
rates are high and should allow for repeated application of photon-addition via
repeat-stages.Comment: 5 pages, 2 figures, 1 tabl
Manipulation Therapy Relieved Pain More Rapidly Than Acupuncture among Lateral Epicondylalgia (Tennis Elbow) Patients: A Randomized Controlled Trial with 8-Week Follow-Up
Radial bone adjustment manipulation treatment may be effective to reduce pain rapidly in lateral epicondylalgia patients and the pathological tension in the biceps brachii muscle is highly concerned. To prove this hypothesis, we conducted a randomized controlled trial and included 35 patients with lateral epicondylalgia for more than 2 months. Either manipulation treatment (n=16) or acupuncture (n=19) was given to these patients for 2 weeks and all patients’ symptoms were followed up for 8 weeks after treatment. Both groups demonstrated changes in pain VAS score, grip strength, and DASH questionnaire. Lateral epicondylalgia patients who received manipulation treatment felt pain relief sooner than those who had acupuncture treatments during the first few treatments. However, both acupuncture and manipulation are effective, while the difference has no significance at the 8-week follow-up. The trial was registered with Current Controlled Trials ISRCTN81308551 on 5 February 2016
Scintillation Arc from FRB 20220912A
We present the interstellar scintillation analysis of fast radio burst (FRB)
20220912A during its extremely active episode in 2022 using data from the
Five-hundred-meter Aperture Spherical Radio Telescope (FAST). We detect a
scintillation arc in the FRB's secondary spectrum, which describes the power in
terms of the scattered FRB signals' time delay and Doppler shift. The arc
indicates that the scintillation is caused by a highly localized region of the
ionized interstellar medium (IISM). Our analysis favors a Milky Way origin for
the localized scattering medium but cannot rule out a host galaxy origin. We
present our method for detecting the scintillation arc, which can be applied
generally to sources with irregularly spaced bursts or pulses. These methods
could help shed light on the complex interstellar environment surrounding the
FRBs and in our Galaxy.Comment: SCIENCE CHINA Physics, Mechanics & Astronomy , Volume 67, Issue 1:
219512 (2024
LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) The survey science plan
We describe the current plans for a spectroscopic survey of millions of stars
in the Milky Way galaxy using the Guo Shou Jing Telescope (GSJT, formerly the
Large Area Multi-Object Spectroscopic Telescope - LAMOST). The survey will
obtain spectra for 2.5 million stars brighter than during dark/grey
time, and 5 million stars brighter than or on nights that are
moonlit or have low transparency. The survey will begin in fall of 2012, and
will run for at least four years. The telescope design constrains the optimal
declination range for observations to , and site
conditions lead to an emphasis on stars in the direction of the Galactic
anticenter. The survey is divided into three parts with different target
selection strategies: disk, anticenter, and spheroid. The resulting dataset
will be used to study the merger history of the Milky Way, the substructure and
evolution of the disks, the nature of the first generation of stars through
identification of the lowest metallicity stars, and star formation through
study of open clusters and the OB associations. Detailed design of the LEGUE
survey will be completed after a review of the results of the pilot survey in
summer 2012.Comment: 19 pages, 1 figure, accepted for publication in RA
FAST observations of an extremely active episode of FRB 20201124A: IV. Spin Period Search
We report the properties of more than 800 bursts detected from the repeating
fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter
Aperture Spherical radio telescope (FAST) during an extremely active episode on
UTC September 25th-28th, 2021 in a series of four papers. In this fourth paper
of the series, we present a systematic search of the spin period and linear
acceleration of the source object from both 996 individual pulse peaks and the
dedispersed time series. No credible spin period was found from this data set.
We rule out the presence of significant periodicity in the range between 1 ms
to 100 s with a pulse duty cycle (when the profile is defined
by a von-Mises function, not a boxcar function) and linear acceleration up to
m s in each of the four one-hour observing sessions, and up to
m s in all 4 days. These searches contest theoretical scenarios
involving a 1 ms to 100 s isolated magnetar/pulsar with surface magnetic field
G and a small duty cycle (such as in a polar-cap emission mode) or a
pulsar with a companion star or black hole up to 100 M and
hours. We also perform a periodicity search of the fine structures and
identify 53 unrelated millisecond-timescale "periods" in multi-components with
the highest significance of 3.9 . The "periods" recovered from the fine
structures are neither consistent nor harmonically related. Thus they are not
likely to come from a spin period. We caution against claiming spin periodicity
with significance below 4 with multi-components from one-off
FRBs. We discuss the implications of our results and the possible connections
between FRB multi-components and pulsar micro-structures.Comment: Accepted by Research in Astronomy and Astrophysics (RAA
FAST observations of an extremely active episode of FRB 20201124A: III. Polarimetry
As the third paper in the multiple-part series, we report the statistical
properties of radio bursts detected from the repeating fast radio burst (FRB)
source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio
telescope (FAST) during an extremely active episode between the 25th and the
28th of September 2021 (UT). We focus on the polarisation properties of 536
bright bursts with . We found that the Faraday rotation
measures (RMs) monotonically dropped from to in the 4-day window. The RM values were compatible with
the values ( to ) reported 4 month ago (Xu et
al. 2022). However, the RM evolution rate in the current observation window was
at least an order of magnitude smaller than the one ($\sim 500\ {\rm rad \
m^{-2}\, day^{-1}}\le 1\ {\rm rad \ m^{-2} day^{-1}}L/IV/I\sigma$) were observed in 33% of
all bursts. The polarisation of single pulses seems to follow certain complex
trajectories on the Poincar\'e sphere, which may shed light on the radiation
mechanism at the source or the plasma properties along the path of FRB
propagation.Comment: 25 pages, 16 figures. Accepted by Research in Astronomy and
Astrophysics (RAA
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