Aharonov-Bohm Effect at liquid-nitrogen temperature: Frohlich superconducting quantum device

The Aharonov-Bohm (AB) effect has been accepted and has promoted interdisciplinary scientific activities in modern physics. To observe the AB effect in condensed matter physics, the whole system needs to maintain phase coherence, in a tiny ring of the diameter 1 micrometer and at low temperatures below 1 K. We report that AB oscillations have been measured at high temperature 79 K by use of charge-density wave (CDW) loops in TaS3 ring crystals. CDW condensate maintained macroscopic quantum coherence, which extended over the ring circumference 85 micrometer. The periodicity of the oscillations is h/2e in accuracy within a 10 percent range. The observation of the CDW AB effect implies Frohlich superconductivity in terms of macroscopic coherence and will provide a novel quantum interference device running at room temperature.Comment: 11 pages, 4 figure

A Microscopic Mechanism for Muscle's Motion

The SIRM (Stochastic Inclined Rods Model) proposed by H. Matsuura and M. Nakano can explain the muscle's motion perfectly, but the intermolecular potential between myosin head and G-actin is too simple and only repulsive potential is considered. In this paper we study the SIRM with different complex potential and discuss the effect of the spring on the system. The calculation results show that the spring, the effective radius of the G-actin and the intermolecular potential play key roles in the motion. The sliding speed is about $4.7\times10^{-6}m/s$ calculated from the model which well agrees with the experimental data.Comment: 9 pages, 6 figure

XAFS analyses of molten metal fluorides

X-ray absorption fine structure studies of molten metal fluorides containing the materials related to nuclear engineering are intensively summarized. By using XAFS spectra data of divalent and trivalent cation metal fluorides in molten state which have been collected by authors’ group for a few years, local structure have been extracted and discussed systematically in conjunction with other spectroscopic studies and numerical calculations. In molten divalent fluorides, tetrahedral coordination of fluorides around a cation is predominant. In the case of pure molten trivalent fluorides, structure with more than 6-coordination has been suggested in some cases, but octahedral coordination structure is much stabilized at heavier rare earth metal fluorides. By mixing with alkali metal fluorides, it is a general trend that inter-ionic distances keep constant, but coordination number of fluorides decreases. In experimental chapter, all the details of sample preparation, furnace installation, X-ray optics setups and data analyses procedures are explained. Finally, future expectations of XAFS technique are also suggested

Melting Pattern of Diquark Condensates in Quark Matter

Thermal color superconducting phase transitions in high density three-flavor quark matter are investigated in the Ginzburg-Landau approach. Effects of nonzero strange quark mass, electric and color charge neutrality, and direct instantons are considered. Weak coupling calculations show that an interplay between the mass and electric neutrality effects near the critical temperature gives rise to three successive second-order phase transitions as the temperature increases: a modified color-flavor locked (mCFL) phase (ud, ds, and us pairings) -> a ``dSC'' phase (ud and ds pairings) -> an isoscalar pairing phase (ud pairing) -> a normal phase (no pairing). The dSC phase is novel in the sense that while all eight gluons are massive as in the mCFL phase, three out of nine quark quasiparticles are gapless.Comment: minor changes in the text, fig.2 modifie

Electric Polarization Induced by a Proper Helical Magnetic Ordering in a Delafossite Multiferroic CuFe1-xAlxO2

Multiferroic CuFe1-xAlxO2 (x=0.02) exhibits a ferroelectric ordering accompanied by a proper helical magnetic ordering below T=7K under zero magnetic field. By polarized neutron diffraction and pyroelectric measurements, we have revealed a one-to-one correspondence between the spin helicity and the direction of the spontaneous electric polarization. This result indicates that the spin helicity of the proper helical magnetic ordering is essential for the ferroelectricity in CuFe1-xAlxO2. The induction of the electric polarization by the proper helical magnetic ordering is, however, cannot be explained by the Katsura-Nagaosa-Balatsky model, which successfully explains the ferroelectricity in the recently explored ferroelectric helimagnets, such as TbMnO3. We thus conclude that CuFe1-xAlxO2 is a new class of magnetic ferroelectrics.Comment: 4 pages, 4 figure