79 research outputs found
Precise measurement of positronium hyperfine splitting using the Zeeman effect
Positronium is an ideal system for the research of the quantum
electrodynamics (QED) in bound state. The hyperfine splitting (HFS) of
positronium, , gives a good test of the bound state
calculations and probes new physics beyond the Standard Model. A new method of
QED calculations has revealed the discrepancy by 15\,ppm (3.9) of
between the QED prediction and the experimental
average. There would be possibility of new physics or common systematic
uncertainties in the previous all experiments. We describe a new experiment to
reduce possible systematic uncertainties and will provide an independent check
of the discrepancy. We are now taking data and the current result of
has been obtained so far. A measurement with a precision of (ppm) is
expected within a year.Comment: 8 pages, 8 figures, 2 tables, proceeding of LEAP2011, accepted by
Hyperfine Interaction
A comprehensive survey on quantum computer usage: How many qubits are employed for what purposes?
Quantum computers (QCs), which work based on the law of quantum mechanics,
are expected to be faster than classical computers in several computational
tasks such as prime factoring and simulation of quantum many-body systems. In
the last decade, research and development of QCs have rapidly advanced. Now
hundreds of physical qubits are at our disposal, and one can find several
remarkable experiments actually outperforming the classical computer in a
specific computational task. On the other hand, it is unclear what the typical
usages of the QCs are. Here we conduct an extensive survey on the papers that
are posted in the quant-ph section in arXiv and claim to have used QCs in their
abstracts. To understand the current situation of the research and development
of the QCs, we evaluated the descriptive statistics about the papers, including
the number of qubits employed, QPU vendors, application domains and so on. Our
survey shows that the annual number of publications is increasing, and the
typical number of qubits employed is about six to ten, growing along with the
increase in the quantum volume (QV). Most of the preprints are devoted to
applications such as quantum machine learning, condensed matter physics, and
quantum chemistry, while quantum error correction and quantum noise mitigation
use more qubits than the other topics. These imply that the increase in QV is
fundamentally relevant, and more experiments for quantum error correction, and
noise mitigation using shallow circuits with more qubits will take place.Comment: 14 pages, 5 figures, figures regenerate
The Quiescent Intracluster Medium in the Core of the Perseus Cluster
Clusters of galaxies are the most massive gravitationally-bound objects in
the Universe and are still forming. They are thus important probes of
cosmological parameters and a host of astrophysical processes. Knowledge of the
dynamics of the pervasive hot gas, which dominates in mass over stars in a
cluster, is a crucial missing ingredient. It can enable new insights into
mechanical energy injection by the central supermassive black hole and the use
of hydrostatic equilibrium for the determination of cluster masses. X-rays from
the core of the Perseus cluster are emitted by the 50 million K diffuse hot
plasma filling its gravitational potential well. The Active Galactic Nucleus of
the central galaxy NGC1275 is pumping jetted energy into the surrounding
intracluster medium, creating buoyant bubbles filled with relativistic plasma.
These likely induce motions in the intracluster medium and heat the inner gas
preventing runaway radiative cooling; a process known as Active Galactic
Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus
cluster core, which reveal a remarkably quiescent atmosphere where the gas has
a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from
the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s
is found across the 60 kpc image of the cluster core. Turbulent pressure
support in the gas is 4% or less of the thermodynamic pressure, with large
scale shear at most doubling that estimate. We infer that total cluster masses
determined from hydrostatic equilibrium in the central regions need little
correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July
The ASTRO-H X-ray Observatory
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly
successful X-ray missions initiated by the Institute of Space and Astronautical
Science (ISAS). ASTRO-H will investigate the physics of the high-energy
universe via a suite of four instruments, covering a very wide energy range,
from 0.3 keV to 600 keV. These instruments include a high-resolution,
high-throughput spectrometer sensitive over 0.3-2 keV with high spectral
resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in
the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers
covering 5-80 keV, located in the focal plane of multilayer-coated, focusing
hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12
keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and
a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the
40-600 keV band. The simultaneous broad bandpass, coupled with high spectral
resolution, will enable the pursuit of a wide variety of important science
themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical
Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to
Gamma Ray
Hitomi (ASTRO-H) X-ray Astronomy Satellite
The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month
Hitomi X-Ray Studies of Giant Radio Pulses from the Crab Pulsar
To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2300 keV band and the Kashima NICT radio telescope in the 1.41.7 GHz band with a net exposure of about 2 ks on 2016 March 25, just before the loss of the Hitomi mission. The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1000 and 100 GRPs were simultaneously observed at the main pulse and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main pulse or inter-pulse phase. All variations are within the 2 fluctuations of the X-ray fluxes at the pulse peaks, and the 3 upper limits of variations of main pulse or inter-pulse GRPs are 22% or 80% of the peak flux in a 0.20 phase width, respectively, in the 2300 keV band. The values for main pulse or inter-pulse GRPs become 25% or 110%, respectively, when the phase width is restricted to the 0.03 phase. Among the upper limits from the Hitomi satellite, those in the 4.510 keV and 70300 keV bands are obtained for the first time, and those in other bands are consistent with previous reports. Numerically, the upper limits of the main pulse and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) 10(exp 11) erg cm(exp 2), respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magnetosphere. Although the number of photon-emitting particles should temporarily increase to account for the brightening of the radio emission, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a >0.02% brightening of the pulse-peak flux under such conditions
Apparent and True Availabilities of Amino Acids from Several Protein Sources for Fingerling Rainbow Trout, Common Carp, and Red Sea Bream
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