428 research outputs found
Observation of Jonscher Law in AC Hopping Conduction of Electron-Doped Nanoporous Crystal 12CaO7Al2O3 in THz Frequency Range
We have performed terahertz time-domain spectroscopy of carrier-doped
nanoporous crystal 12CaO7Al2O3 showing the Mott variable range hopping at room
temperature. The real part of the dielectric constant clearly demonstrates the
nature of localized carriers. The frequency dependence of both the real and
imaginary parts of the dielectric constant can be simply explained by assuming
two contributions: a dielectric response by the parent compound with no
carriers and an AC hopping conduction with the Jonscher law generally reported
up to GHz range. The possible obedience to the Jonscher law in the THz range
suggests a relaxation time of the hopping carriers much faster than 1ps in the
carrier-doped 12CaO7Al2O3.Comment: 4pages 3figures. to be published in Phys. Rev.
THz Wave Propagation on Strip Lines: Devices, Properties, and Applications
We report the propagation characteristics of THz pulses on micro-strip-lines and coplanar strip-lines, in which low permittivity polymer materials are used as the dielectric layer or the substrate. As a result of the low attenuation and small dispersion in the devices, the spectral width up to 3 THz can be achieved even after the 1 mm propagation. Spectroscopic characterizations of liquid or powder specimens are demonstrated using the devices. We also show a possibility of realizing a very low attenuation using a quadrupole mode in three strip coplanar lines on the polymer substrate
An Analysis of Mutual Communication between Qubits by Capacitive Coupling
A behavior of a two qubit system coupled by the electric capacitance has been
studied quantum mechanically. We found that the interaction is essentially the
same as the one for the dipole-dipole interaction; i.e., qubit-qubit coupling
of the NMR quantum gate. Therefore a quantum gate could be constructed by the
same operation sequence for the NMR device if the coupling is small enough. The
result gives an information to the effort of development of the devices
assuming capacitive coupling between qubits.Comment: 8 pages, 2 figures Revised and Replaced on Apr. 8 200
Enantiopure and racemic radical-cation salts of B(malate)2−anions with BEDT-TTF
We have synthesized the first examples of radical-cation salts of BEDT-TTF with chiral borate anions, [B(malate)2]−, prepared from either enantiopure or racemic bidentate malate ligands. In the former case only one of two diastereoisomers of the borate anion is incorporated, while for the hydrated racemic salt one racemic pair of borate anions containing a R and a S malate ligand is incorporated. Their conducting and magnetic properties are reported. The tight-binding band calculation indicates that the chiral salt has an effective half-filled flat band, which is likely to be caused by the chiral structural feature
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