Four-dimensional CP1+^1+ U(1) lattice gauge theory for 3D antiferromagnets: Phase structure, gauge bosons and spin liquid

In this paper we study the lattice CP$^1$ model in (3+1) dimensions coupled with a dynamical compact U(1) gauge field. This model is an effective field theory of the $s={1 \over 2}$ antiferromagnetic Heisenberg spin model in three spatial dimensions. By means of Monte Carlo simulations, we investigate its phase structure. There exist the Higgs, Coulomb and confinement phases, and the parameter regions of these phases are clarified. We also measure magnetization of O(3) spins, energy gap of spin excitations, and mass of gauge boson. Then we discuss the relationship between these three phases and magnetic properties of the high-$T_{\rm c}$ cuprates, in particular the possibility of deconfined-spinon phase. Effect of dimer-like spin exchange coupling and ring-exchange coupling is also studied.Comment: 4pages, 10 figure

X-ray magnetic circular dichroism and photoemission study of the diluted ferromagnetic semiconductor Zn1−x_{1-x}Crx_xTe

We have performed x-ray magnetic circular dichroism (XMCD) and valence-band photoemission studies of the diluted ferromagnetic semiconductor Zn$_{1-x}$Cr$_x$Te. XMCD signals due to ferromagnetism were observed at the Cr 2p absorption edge. Comparison with atomic multiplet calculations suggests that the magnetically active component of the Cr ion was divalent under the tetrahedral crystal field with tetragonal distortion along the crystalline a-, b-, and c-axes. In the valence-band spectra, spectral weight near the Fermi level was strongly suppressed, suggesting the importance of Jahn-Teller effect and the strong Coulomb interaction between the Cr 3d electrons

Hadron resonances with coexistence of different natures

We discuss coexistence/mixing of different natures of hadronic composite (molecule) and elementary (quark-intrinsic) ones in hadron resonances. The discussions here are based on our previous publications on the origin of hadron resonances \cite{Hyodo:2008xr}, exotic $\bar D$ meson-nucleons as hadronic composites containing one anti-heavy quark \cite{Yamaguchi:2011xb}, and the study of $a_1$ as a typical example to show explicitly the mixing of the two different natures \cite{Nagahiro:2011jn}. In all cases, interactions are derived from the chiral dynamics of the light flavor sector. These interactions generate in various cases hadronic composite/molecule states, serving varieties of structure beyond the conventional quark model.Comment: Proceedings for Hadron Nuclear Physics (HNP) 2011, Pohang, Korea, February 21-24 (2011

ニホン シカ ダイガク リンショウ ジッシュウ シサツ ホウコク

We made a field trip to Nippon Dental University Hospital to observe its clinical training practices on February 16, 2011. Distinctive features of the clinical training system were as follows. 1) Clinical training is given to fifth-year students. Students in the sixth-year are intent on their studies. 2) There is a one-month overlap in the training periods between these two groups, as patients are handed over from the fifth- to the fourth-year students. This handover is a student-led event. 3) After this period, pre-clinical training is given to the fifth-year students for three months, and then clinical training begins. 4) Patients are requested to evaluate and give feedback to the students treating them. Each student should receive five or more evaluations. 5) A mentor system was introduced in 2005. According to our findings and the results of the“ World Café” held on the same day with trainee dentists and fifth-year students, we identified the following means of improving our clinical training system. First, students under clinical training are now permitted to participate in case-report conferences of trainee dentists, as of 2011. This program was introduced based on the concept of top-down processing to help students form perceptions about cases and treatment. Second, the necessity of a faculty-development program focused on clinical training is recognized, to standardize and improve the guidance given to students by advising doctors. Third, the mentor system and the“ World Café” need more attention as elements of clinical training to support students and motivate improvement

High Energy Particle Measurements during Long Discharge in LHD

The spatial resolved energy spectra can be observed during a long discharge of NBI plasma bycontinuously scanning the neutral particle analyzer. In these discharges, the plasmas are initiated by the ECH heating, after that NBI#2 (Co-injection) sustains the plasma during 40-60 seconds. The scanned pitch angle is from 44 degrees to 74 degrees. The injected neutral beam (hydrogen) energy of NBI#2 is only 130 keV because the original ion source polarity is negative. The shape of spectra is almost similar from 44 degrees to 53 degrees. However the spectra from 55 degrees are strongly varied. It reflects the injection pitch angle of the beam according to the simulation (53 degrees ot R* = 3.75 m in simulation). The beam keeps the pitch angle at incidence until the beam energy becomes to the energy, which the pitch angle scattering is occurred by the energy loss due to the electron collision. The low flux region can be observed around 10-15 keV, which is 15 times of the electron temperature. The energy region may be equal to the energy at which the pitch angle scattering is occurred. At the energy, the particle is scattered by the collision with the plasma ions and some of particles may run away from the plasma because they have a possibility to enter the loss cone. According to the simulation, the loss cone can be expected at the 10 keV with the small angular dependence. The depth of the loss cone is deep at the small pitch angle. The hollow in the spectrum may be concluded to be the loss cone as the tendency is almost agreed with the experimental result

Multi-functional Diagnostic Method with Tracer-encapsulated Pellet Injection

In order to obtain a better understanding of impurity transport in magnetically confined plasmas, a Tracer-Encapsulated Soild PELlet (TESPEL) has been developed. The essential points of the TESPEL are as follows: the TESPEL has a double-layered structure, and a tracer impurity, the amount of which can be known precisely, is embedded as an inner core. This structure enables us to deposit the tracer impurity locally inside the plasma. From experiences of developing the TESPEL production technique and its injection experiments, it became clear that various plasma properties can be studied by the TESPEL injection. There are not only impurity transport in the plasma but also transport both outside and inside of the magnetic island O-point, heat transport and high-energy neutral particle flux. Therefore, the TESPEL injection has a favorable multi-functional diagnostic capability. Furthermore a Tracer-Encapsulated Cryogenic PELlet (TECPEL) has been also developed. The TECPEL has an advantage over the TESPEL in terms of no existence of carbons in the outer layer. The TECPEL injector was installed at LHD in December 2005, and the preliminary injection experiments have been carried out

Magnetized Fast Isochoric Laser Heating for Efficient Creation of Ultra-High-Energy-Density States

The quest for the inertial confinement fusion (ICF) ignition is a grand challenge, as exemplified by extraordinary large laser facilities. Fast isochoric heating of a pre-compressed plasma core with a high-intensity short-pulse laser is an attractive and alternative approach to create ultra-high-energy-density states like those found in ICF ignition sparks. This avoids the ignition quench caused by the hot spark mixing with the surrounding cold fuel, which is the crucial problem of the currently pursued ignition scheme. High-intensity lasers efficiently produce relativistic electron beams (REB). A part of the REB kinetic energy is deposited in the core, and then the heated region becomes the hot spark to trigger the ignition. However, only a small portion of the REB collides with the core because of its large divergence. Here we have demonstrated enhanced laser-to-core energy coupling with the magnetized fast isochoric heating. The method employs a kilo-tesla-level magnetic field that is applied to the transport region from the REB generation point to the core which results in guiding the REB along the magnetic field lines to the core. 7.7 $\pm$ 1.3 % of the maximum coupling was achieved even with a relatively small radial area density core ($\rho R$ $\sim$ 0.1 g/cm$^2$). The guided REB transport was clearly visualized in a pre-compressed core by using Cu-$K_\alpha$ imaging technique. A simplified model coupled with the comprehensive diagnostics yields 6.2\% of the coupling that agrees fairly with the measured coupling. This model also reveals that an ignition-scale areal density core ($\rho R$ $\sim$ 0.4 g/cm$^2$) leads to much higher laser-to-core coupling ($>$ 15%), this is much higher than that achieved by the current scheme

Spatial resolved high-energy particle diagnostic system using time-of-flight neutral particle analyzer in Large Helical Device

The time-of-flight-type neutral particle analyzer has an ability of horizontal scanning from 40 to 100° of the pitch angle. The information from the spatially resolved energy spectrum gives not only the ion temperature but also the information of the particle confinement and the electric field in plasmas. We have been studying the energy distributions at various magnetic configurations in the neutral beam injection (NBI) plasma. The spatially resolved energy spectra can be observed during long discharges of the NBI plasma by continuous scanning of the neutral particle analyzer. The shape of spectra is almost similar from 44° to 53°. However, the spectra from 55° are strongly varied. They reflect the injection pitch angle of the beam. The pitch angle scanning experiment during the long discharge of NBI plasma has also been made under the reversal of the magnetic field direction. NBI2 becomes counter injected with the reversal. We can easily observe the difference between co- and counter injections of NBI. During the electron cyclotron heating in the low-density plasma for the formation of the internal thermal barrier, large neutral particle increase or decease can be observed. The degree of the increase/decrease depends on the energy and the density. The reason for the variation of the particle flux is that the orbit of the trapped particle changes due to the electric field formed by the strong electron cyclotron heating