2,185 research outputs found
Dark filaments observed at 8.3mm and 3.1mm wavelength
Mapping of the sun was made at 3.1mm (98 GHz) and 8.3mm (36 GHz) wavelengths with a 45m dish radio telescope at the Nobeyama Cosmic Radio Observatory. The depressions associated with large H alpha filaments are derived to be -0.2 at 8.3mm and -0.05 at 3.1mm, which are darker than the values inferred by Raoult et al. (1979
Regulation of the terminal steps in peptidoglycan biosynthesis in ether-treated cells of Escherichia coli
Phase diagram of the one dimensional Hubbard-Holstein Model at 1/2 and 1/4 filling
The Hubbard-Holstein model is one of the simplest to incorporate both
electron-electron and electron-phonon interactions. In one dimension at half
filling the Holstein electron-phonon coupling promotes onsite pairs of
electrons and a Peierls charge density wave while the Hubbard onsite Coulomb
repulsion U promotes antiferromagnetic correlations and a Mott insulating
state. Recent numerical studies have found a possible third intermediate phase
between Peierls and Mott states. From direct calculations of charge and spin
susceptibilities, we show that (i) As the electron-phonon coupling is
increased, first a spin gap opens, followed by the Peierls transition. Between
these two transitions the metallic intermediate phase has a spin gap, no charge
gap, and properties similar to the negative-U Hubbard model. (ii) The
transitions between Mott/intermediate and intermediate/Peierls states are of
the Kosterlitz-Thouless form. (iii) For larger U the two transitions merge at a
tritical point into a single first order Mott/Peierls transition. In addition
we show that an intermediate phase also occurs in the quarter-filled model.Comment: 10 pages, 10 eps figure
Nodal Superconducting Order Parameter and Thermodynamic Phase Diagram of (TMTSF)2ClO4
The organic materials (TMTSF)2X are unique unconventional superconductors
with archetypal quasi-one-dimensional (Q1D) electronic structures. Here, based
on our comprehensive field-angle-resolved calorimetry of (TMTSF)2ClO4, we
succeeded in mapping the nodal gap structure for the first time in Q1D systems,
by discriminating between the Fermi wavevectors and Fermi velocities. In
addition, the thermodynamic phase diagrams of (TMTSF)2ClO4 for all principal
field directions are obtained. These findings, providing strong evidence of
nodal spin-singlet superconductivity, serves as solid bases for further
elucidation of anomalous superconducting phenomena in (TMTSF)2X.Comment: 7 pages, 7 figures, including Supplemental Information added at the
end of the manuscrip
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