Chiral pumping effect induced by rotating electric fields

We propose an experimental setup using 3D Dirac semimetals to access a novel phenomenon induced by the chiral anomaly. We show that the combination of a magnetic field and a circularly polarized laser induces a finite charge density with an accompanying axial current. This is because the circularly polarized laser breaks time-reversal symmetry and the Dirac point splits into two Weyl points, which results in an axial-vector field. We elucidate the appearance of the axial-vector field with the help of the Floquet theory by deriving an effective Hamiltonian for high-frequency electric fields. This anomalous charge density, i.e. the chiral pumping effect, is a phenomenon reminiscent of the chiral magnetic effect with a chiral chemical potential. We explicitly compute the pumped density and the axial-current expectation value. We also take account of coupling to the chiral magnetic effect to calculate a balanced distribution of charge and chirality in a material that behaves as a chiral battery.Comment: 6 pages, 3 figures; a new section added to discuss coupling of the CPE and the CME, a wrong sign corrected, typos fixed, elaborated for better readabilit

Weak Decay of Λ\Lambda in Nuclei: Direct Quark Mechanism vs Meson Exchange

Nonmesonic decays of $\Lambda$ in nuclear medium and light hypernuclei are studied by using the $\Lambda N \to NN$ weak transition potential derived from the meson exchange mechanism and the direct quark mechanism. The long range part of the transition potential is described by exchanges of the pseudoscalar mesons ($\pi$, $K$, $\eta$), while the vector mesons ($\rho$, $\omega$, $K^\ast$) may be considered as the medium- and short-range part in the meson exchange picture. We propose the direct quark transition potential as the short range part, which is derived from the matrix elements of the $\Delta S=1$ effective weak Hamiltonian in the two baryon states. The results indicate that the direct quark contribution is significantly large and its behavior is qualitatively different from the vector meson exchanges. We also find that the decay rate is sensitive to the choice of form factor and that a soft cutoff must be used for the pion-baryon verteces so that the strong tensor transition is suppressed. We find that the $\pi + K + DQ$ results are compatible with experiment although the $n/p$ ratio is still too large. The $\pi^+$ decays of light hypernuclei are related to the \DI=3/2 amplitudes of the nonmesonic decay. The role of chiral symmetry for the pionic decays are discussed.Comment: 10 pages, Talk presented by Makoto Oka at the APCTP Workshop on Strangeness Nuclear Physics (SNP'99), February, 199

Charmonium spectra at finite temperature from QCD sum rules with the maximum entropy method

Charmonia spectral functions at finite temperature are studied using QCD sum rules in combination with the maximum entropy method. This approach enables us to directly obtain the spectral function from the sum rules, without having to introduce any specific assumption about its functional form. As a result, it is found that while J/psi and eta_c manifest themselves as significant peaks in the spectral function below the deconfinement temperature T_c, they quickly dissolve into the continuum and almost completely disappear at temperatures between 1.0 T_c and 1.1 T_c.Comment: 4 pages, 1 figure; typos corrected, version published in Phys. Rev. Let

A Research on the Treatment of Complex Sulphide Ores. V : On the Recovery of Sulphur

Hydrogen sulphide was oxidized with air in the presence of iron, manganese or vanadium oxide as catalyst. The main product of the oxidation was either elementary sulphur or sulphur dioxide according to the ratio of air to hydrogen sulphide. When hydrogen sulphide was mixed to about 29% with air, a maximum yield of sulphur was obtained amounting to about 90% and sulphur dioxide which was formed simultaneously was a little. Amount of sulphur formed decreased and that of sulphur dioxide increased as the ratio of air to hydrogen sulphide was increased. With a mixture containing 12% of hydrogen sulphide, 80% of the sulphur was oxidized to sulphur dioxide and the remainder was found as elementary sulphur. The oxidation took place at relatively low temperature At 200～400℃, 90% of the sulphur was recoreved as elementary sulphur with a mixture which contained 28% of hydrogen sulphide. An effect of flowing rate on the reaction was little

Stress Wave Propagation through Cohesive Soil

Generally, there exist an inelastic deformation and an energy dissipation during the stress wave propagation through cohesive soil. In order to describe these characteristics, the authors proposed the constitutive equation of normally consolidated clay. The phenomenological nature of the parameters involved in the stress-strain relation was investigated in detail by using the triaxial test results and the stress wave propagation test results. In these test the pore water pressure was measured and its value was compared with the calculated result by using the constitutive equation of clay. As a result, the proposed stress-strain relation was very effective for interpreting the behavior of cohesive soil

Multilayer graphene shows intrinsic resistance peaks in the carrier density dependence

Since the advent of graphene, a variety of studies have been performed to elucidate its fundamental physics, or to explore its practical applications. Gate-tunable resistance is one of the most important properties of graphene and has been studied in 1-3 layer graphene in a number of efforts to control the band gap to obtain a large on-off ratio. On the other hand, the transport property of multilayer graphene with more than three layers is less well understood. Here we show a new aspect of multilayer graphene. We found that four-layer graphene shows intrinsic peak structures in the gate voltage dependence of its resistance at zero magnetic field. Measurement of quantum oscillations in magnetic field confirmed that the peaks originate from the specific band structure of graphene and appear at the carrier density for the bottoms of conduction bands and valence bands. The intrinsic peak structures should generally be observed in AB-stacked multilayer graphene. The present results would be significant for understanding the physics of graphene and making graphene FET devices

シカヨウ レーザー ノ リンショウ オウヨウ ニツイテ

Several types of lasers have been developed and tried to be clinically applied to the oral area. Lasers have been used for various clinical practices, diagnosis and prevention of dental caries, treatment for periodontal disease, hypersensitive dentin, relieving pain, and root canal infections. The Er:YAG laser is the only dental laser that has the potential to ablate both dental hard tissue and soft tissue. In this report, I introduce the practical procedure of some cases using the Er:YAG laser, and discuss the utility of Er:YAG laser application on oral soft tissue or hard tissue