Utsunomiya University

About: Utsunomiya University is a education organization based out in Utsunomiya, Japan. It is known for research contribution in the topics: Laser & Holography. The organization has 4139 authors who have published 6812 publications receiving 91975 citations. The organization is also known as: Utsunomiya daigaku.

Effects of the quark field on the ghost propagator of lattice Landau gauge QCD

Abstract: Infrared features of the ghost propagator of color-diagonal and color antisymmetric ghost propagator of quenched SU(2) and quenched SU(3) are compared with those of unquenched Kogut-Susskind fermion SU(3) lattice Landau gauge. We compare (i) the fluctuation of the ghost propagator, (ii) the ghost condensate parameter $v$ of the local composite operator (LCO) approach, and (iii) the Binder cumulant of color antisymmetric ghost propagator between quenched and unquenched configurations. The color-diagonal SU(3) ghost dressing function of unquenched configurations has weaker singularity than the quenched configurations. In both cases fluctuations become large in $ql0.5\text{ }\text{ }\mathrm{GeV}$. The ghost condensate parameter $v$ in the ghost propagator of the unquenched ${\mathrm{MILC}}_{c}$ configuration samples is $\ensuremath{\sim}0.002--0.04\text{ }\text{ }{\mathrm{GeV}}^{2}$ while that of the SU(2) parallel tempering samples is consistent with 0. The Binder cumulant defined as $U(q)=1\ensuremath{-}\frac{1}{3}\frac{⟨{\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\phi}}}^{4}⟩}{(⟨{\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\phi}}}^{2}⟩{)}^{2}}$, where $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\phi}}(q)$ is the color antisymmetric ghost propagator measured by the sample average of gauge fixed configurations via parallel tempering method, becomes $\ensuremath{\sim}4/9$ in all the momentum region. The Binder cumulant of the color antisymmetric ghost propagator of quenched SU(2) can be explained by the 3D Gaussian distribution, but that of the unquenched ${\mathrm{MILC}}_{c}$ deviates slightly from that of the eight-dimensional Gaussian distribution. The stronger singularity and large fluctuation in the quenched configuration could be the cause of the deviation of the Kugo-Ojima confinement parameter $c$ from 1, and the presence of ordering in the ghost propagator of unquenched configurations makes it closer to 1.

Propagation of short intense laser pulses in gas-filled capillaries.

Abstract: The guided laser pulse propagation and wake-field generation are studied in a wide (in comparison with the laser spot size) gas-filled capillary with an on-axis gas density depletion, which can be produced by a rapid spin of the capillary around its axis or by radially propagating shock waves generated in a piezoceramic tube. A single equation for the wake-field potential, which describes the fully relativistic plasma response in the presence of optical field ionization (OFI) of a gas, is derived and used to demonstrate a guided propagation of a short intense laser pulse over many Rayleigh lengths in a leaky plasma channel produced by the pulse due to OFI in the capillary filled with a radially inhomogeneous gas. The efficient generation of a regular wake field over long distances suitable for the laser wake-field accelerators is shown.

Complex-amplitude single-pixel imaging.

Abstract: A single-pixel camera can be represented using complex-amplitude. The complex-amplitude representation of input signals and output signals enables us to perform complex-amplitude imaging of an object, particularly profilometry with reflectance measurements or quantitative phase imaging with transmittance measurements. The complex-amplitude representation of optical coding masks and the coherent addition that is performed by interference can directly represent Hadamard patterns having positive and negative values. Furthermore, the residual area of the mask can be used for a reference beam with phase shifting. Such a complex-amplitude imaging system with a single-beam line structure is highly stabile against external disturbances.

Hybrid emulsion spectrometer for the detection of hadronically produced heavy flavor states

Abstract: A hybrid apparatus consisting of a movable emulsion target and a magnetic spectrometer was used in a fixed target Fermilab Tevatron experiment to study the production of heavy quarks by high-energy hadron beams. High-resolution silicon microstrip detectors were used for precise tracking in the dense particle environment. Details of the experimental apparatus, including the data acquisition system, are described.

Altered cerebellum development and dopamine distribution in a rat genetic model with congenital hypothyroidism.

Abstract: Thyroid hormones play crucial roles in the development and functional maintenance of the central nervous system. Despite extensive studies of the neural function of thyroid hormones, little is known about the effects of hypothyroidism on behavioural traits and the mechanisms underlying such effects. In the present study, we report an investigation of congenitally hypothyroid mutant rdw rats, revealing a novel function of thyroid hormones in the central nervous system. The rdw rats were subjected to behavioural analyses such as the rotarod test, open field test and circadian activity measurement. To determine the cause of behavioural disorders, cerebellar morphogenesis was examined by immunohistochemical analysis, and the axonal transport of dopamine in the nigrostriatal pathway was analysed by high-performance liquid chromatography and western blotting. The effects of thyroxine administration to the rdw rats were examined by behavioural analysis. The rdw rats showed severe impairment of motor coordination and balance. This could be explained by the fact that the rats showed severe retardation of cerebellar morphogenesis, which correlates with the small somata and poor dendritic arborisation of Purkinje cells and retarded migration of granule cells particularly during the first two postnatal weeks. Moreover, the rdw rats showed hypoactivity, characterised by decreased circadian locomotor activity. After weaning, thyroxine administration improved the dwarfism in rdw rats but had no effect on cerebellar function. In addition, the rdw rats showed anxiety and depression intrinsically to novel surroundings. Interestingly, the rdw rats showed high levels of dopamine in the substantia nigra and low levels in the striatum, an important centre for the coordination of behaviour. Furthermore, low levels of tubulin in the striatum were detected, indicating the aberrant axonal transport of dopamine in the nigrostriatal pathway as a result of the reduced delivery of microtubules. These findings indicate an important function of thyroid hormones in cerebellar formation and in the regulation of axonal transport of dopamine. Moreover, rdw rats will be useful for studies of brain function and behavioural disorders in congenital hypothyroidism.