Monopole Condensation in Lattice SU(2) QCD

This is the short review of Monte-Carlo studies of quark confinement in lattice QCD. After abelian projections both in the maximally abelian and Polyakov gauges, it is seen that the monopole part alone is responsible for confinement. A block spin transformation on the dual lattice suggests that lattice $SU(2)$ QCD is always ( for all $\beta$) in the monopole condensed phase and so in the confinement phase in the infinite volume limit.Comment: Contribution to Confinement '95, March 1995, Osaka, Japan. Names of figure files are corrected. 8 page uuencoded latex file and 10 ps figure

Hole-trapping by Ni, Kondo effect and electronic phase diagram in non-superconducting Ni-substituted La2-xSrxCu1-yNiyO4

In order to investigate the electronic state in the normal state of high-Tc cuprates in a wide range of temperature and hole-concentration, specific-heat, electrical-resistivity, magnetization and muon-spin-relaxation (muSR) measurements have been performed in non-superconducting Ni-substituted La2-xSrxCu1-yNiyO4 where the superconductivity is suppressed through the partial substitution of Ni for Cu without disturbing the Cu-spin correlation in the CuO2 plane so much. In the underdoped regime, it has been found that there exist both weakly localized holes around Ni and itinerant holes at high temperatures. With decreasing temperature, all holes tend to be localized, followed by the occurrence of variable-range hopping conduction at low temperatures. Finally, in the ground state, it has been found that each Ni2+ ion traps a hole strongly and that a magnetically ordered state appears. In the overdoped regime, on the other hand, it has been found that a Kondo-like state is formed around each Ni2+ spin at low temperatures. In conclusion, the ground state of non-superconducting La2-xSrxCu1-yNiyO4 changes upon hole doping from a magnetically ordered state with the strong hole-trapping by Ni2+ to a metallic state with Kondo-like behavior due to Ni2+ spins, and the quantum phase transition is crossover-like due to the phase separation into short-range magnetically ordered and metallic regions.Comment: 9 pages, 8 figures, accepted for publication in Phys. Rev.

Time-Dependent Dynamics of the Bose-Fermi Mixed Condensed System

We study the monopole oscillation in the bose-fermi mixed condensed system by performing the time-dependent Gross-Pitaevsky (GP) and Vlasov equations. We find that the big damping exists for the fermion oscillation in the mixed system even at zero temperatureComment: 5pages, 2 figure

Isoscalar and Isovector spin response in sd−sd- shell nuclei

The spin magnetic dipole transitions and the neutron-proton spin-spin correlations in $sd-$shell even-even nuclei with $N=Z$ are investigated using shell model wave functions taking into accout enhanced isoscalar (IS) spin-triplet pairing as well as the effective spin operators. It was shown that the IS pairing and the effective spin operators gives a large quenching effect on the IV spin transitions to be consistent with observed data by $(p,p')$ experiments. On the other hand, the observed IS spin strength show much smaller quenching effect than expected by the calculated results. The IS pairing gives a substantial quenching effect on the spin magnetic dipole transitions, especially on the isovector (IV) ones. Consequently, an enhanced isoscalar spin-triplet pairing interaction enlarges the proton-neutron spin-spin correlation deduced from the difference between the isoscalar (IS) and the IV sum rule strengths. The beta-decay rates and the IS magnetic moments of $sd-$shell are also examined in terms of the IS pairing as well as the effective spin operators.Comment: 13pages, 12figures, 3tables. arXiv admin note: text overlap with arXiv:1607.0588

Effective Monopole Action at Finite Temperature in SU(2) Gluodynamics

Effective monopole action at finite temperature in SU(2) gluodynamics is studied on anisotropic lattices. Using an inverse Monte-Carlo method and the blockspin transformation for space directions, we determine 4-dimensional effective monopole action at finite temperature. We get an almost perfect action in the continuum limit under the assumption that the action is composed of two-point interactions alone. It depends on a physical scale $b_s$ and the temperature $T$. The temperature-dependence appears with respect to the spacelike monopole couplings in the deconfinement phase, whereas the timelike monopole couplings do not show any appreciable temperature-dependence. The dimensional reduction of the 4-dimensional SU(2) gluodynamics ((SU(2))$_{4D}$) at high temperature is the 3-dimensional Georgi-Glashow model ($(GG)_{3D}$). The latter is studied at the parameter region obtained from the dimensional red uction. We compare the effective instanton action of $(GG)_{3D}$ with the timelike monopole action obtained from (SU(2))$_{4D}$. We find that both agree very well for $T \ge 2.4T_c$ at large $b$ region. The dimensional reduction works well also for the effective action.Comment: 34 pages, 23 figure