12,364 research outputs found
Non-Abelian Dual Superconductor Picture for Quark Confinement
We give a theoretical framework for defining and extracting non-Abelian
magnetic monopoles in a gauge-invariant way in SU(N) Yang-Mills theory to study
quark confinement. Then we give numerical evidences that the non-Abelian
magnetic monopole defined in this way gives a dominant contribution to
confinement of fundamental quarks in SU(3) Yang-Mills theory, which is in sharp
contrast to the SU(2) case in which Abelian magnetic monopoles play the
dominant role for quark confinement.Comment: 9 pages, 3 figures (4 ps files); The paper was extensively revised,
focusing especially on the lattice par
Dynamical instability of differentially rotating stars
We study the dynamical instability against bar-mode deformation of
differentially rotating stars. We performed numerical simulation and linear
perturbation analysis adopting polytropic equations of state with the
polytropic index . It is found that rotating stars of a high degree of
differential rotation are dynamically unstable even for the ratio of the
kinetic energy to the gravitational potential energy of .
Gravitational waves from the final nonaxisymmetric quasistationary states are
calculated in the quadrupole formula. For rotating stars of mass
and radius several 10 km, gravitational waves have frequency several 100 Hz and
effective amplitude at a distance of Mpc.Comment: 5 pages, 7 figures, accepted for publication in MNRA
Josephson Plasma in RuSr2GdCu2O8
Josephson plasma in RuSrGdCuO,
RuSrGdCuO (x = 0.3), and
RuSrEuCeCuO (x = 0.5) compounds is
investigated by the sphere resonance method. The Josephson plasma is observed
in a low-frequency region (around 8.5 cm at T ) for
ferromagnetic RuSrGdCuO, while it increases to 35 cm
for non-ferromagnetic RuSrGdCuO (x = 0.3), which
represents a large reduction in the Josephson coupling at ferromagnetic
RuO block layers. The temperature dependence of the plasma does not shift
to zero frequency ({\it i.e.} = 0) at low temperatures, indicating that
there is no transition from the 0-phase to the -phase in these compounds.
The temperature dependence and the oscillator strength of the peak are
different from those of other non-magnetic cuprates, and the origins of these
anomalies are discussed.Comment: to appear in Phys. Rev.B Rapid Com
Vsop2/Astro-G Project
We introduce a new space VLBI project, the Second VLBI Space Observatory
Program (VSOP2), following the success of the VLBI Space Observatory Program
(VSOP1). VSOP2 has 10 times higher angular resolution, up to about 40 micro
arcseconds, 10 times higher frequency up to 43 GHz, and 10 times higher
sensitivity compared to VSOP1. Then VSOP2 should become a most powerful tool to
observe innermost regions of AGN and astronomical masers. ASTRO-G is a
spacecraft for VSOP2 project constructing in ISAS/JAXA since July 2007. ASTRO-G
will be launched by JAXA H-IIA rocket in fiscal year 2012. ASTRO-G and
ground-based facilities are combined as VSOP2. To achieve the good observation
performances, we must realize new technologies. They are large precision
antenna, fast-position switching capability, new LNAs, and ultra wide-band down
link, etc.. VSOP2 is a huge observation system involving ASTRO-G, ground radio
telescopes, tracking stations, and correlators, one institute can not prepare a
whole system of VSOP2. Then we must need close international collaboration to
get sufficient quality of resultant maps and to give a sufficient quantity of
observation time for astronomical community. We formed a new international
council to provide guidance on scientific aspects related of VSOP2, currently
called the VSOP2 International Science Council (VISC2).Comment: 10 pages, 9 figures, proceedings of The Universe under the Microscope
Astrophysics at High Angular Resolutio
The Nagoya cosmic-ray muon spectrometer 3, part 2: Track detector
The twelve wide gap spark chambers were utilized as the track detectors of the Nagoya cosmic-ray muon spectrometer not only to obtain the precise locations of particles, but also to get some information about the correspondences between segments of trajectories. The area of each chamber is 150 x 70 sq cm and the width of a gap is 5 cm. The gas used is He at the atmospheric pressure. Each three pairs of them are placed on both sides of the deflection magnet. All images of sparks for each event are projected through the mirror system and recorded by two cameras stereoscopically. The mean detection efficiency of each chamber is 95 + or - 2% and the spacial resolution (jitter and drift) obtained from the prototype-experiment is 0.12 mm. Maximum detectable momentum of the spectrometer is estimated at about 10 TeV/c taking into account these characteristics together with the effects of the energy loss and multiple Coulomb scattering of muons in the iron magnet
Angular and Abundance Distribution of High-energy Gamma Rays and Neutrons Simulated by GEANT4 Code for Solar Flares
In the solar flare observed on June 3, 2012, high energy gamma-rays and
neutrons were observed. The event includes a remarkable feature of a high
neutron/gamma-ratio in the secondary particles. We have examined whether this
high n/-ratio can be explained by simulation. As a result of
simulations using the GEANT4 program, the high n/-ratio may be
reproduced for the case that helium and other heavy ions were dominantly
accelerated in the flare.Comment: submitted to the Proceeding of The 20th International Symposium on
Very High Energy Cosmic Ray Interaction (ISVHECRI 2018, Nagoya, Japan),
Europian Physics Journa
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