295 research outputs found
Characterization of nonlinear effects in edge filters
A specially designed and produced edge filter with pronounced nonlinear
effects is carefully characterized. The nonlinear effects are estimated at the
intensities close to the laser-induced damage.Comment: 3 page
Optical study of superconducting Ga-rich layers in silicon
We performed phase-sensitive terahertz (0.12 - 1.2 THz) transmission
measurements of Ga-enriched layers in silicon. Below the superconducting
transition, T_{c} = 6.7 K, we find clear signatures of the formation of a
superconducting condensate and of the opening of an energy gap in the optical
spectra. The London penetration depth, \lambda(T), and the condensate density,
n_{s} = \lambda^{2} 0)/\lambda^{2}(T), as functions of temperature demonstrate
behavior, typical for conventional superconductors with \lambda(0) = 1.8 \mu m.
The terahertz spectra can be well described within the framework of Eliashberg
theory with strong electron-phonon coupling: the zero-temperature energy gap is
2\Delta(0) = 2.64 meV and 2\Delta(0)/k_{B}T_{c} = 4.6 \pm 0.1, consistent with
the amorphous state of Ga. At temperatures just above T_{c}, the optical
spectra demonstrate Drude behavior.Comment: 5 pages, 4 figure
Far-infrared and submillimeter-wave conductivity in electron-doped cuprate La_{2-x}Ce_xCuO_4
We performed far-infrared and submillimeter-wave conductivity experiments in
the electron-doped cuprate La_{2-x}Ce_xCuO_4 with x = 0.081 (underdoped regime,
T_c = 25 K). The onset of the absorption in the superconducting state is
gradual in frequency and is inconsistent with the isotropic s-wave gap.
Instead, a narrow quasiparticle peak is observed at zero frequency and a second
peak at finite frequencies, clear fingerprints of the conductivity in a d-wave
superconductor. A far-infrared conductivity peak can be attributed to 4Delta_0,
or to 2Delta_0 + Delta_spin, where Delta_spin is the resonance frequency of the
spin-fluctuations. The infrared conductivity as well as the suppression of the
quasiparticle scattering rate below T_c are qualitatively similar to the
results in the hole-doped cuprates.Comment: 5 pages, 4 figures include
Renormalization of the asymptotically expanded Yang-Mills spectral action
We study renormalizability aspects of the spectral action for the Yang-Mills
system on a flat 4-dimensional background manifold, focusing on its asymptotic
expansion. Interpreting the latter as a higher-derivative gauge theory, a
power-counting argument shows that it is superrenormalizable. We determine the
counterterms at one-loop using zeta function regularization in a background
field gauge and establish their gauge invariance. Consequently, the
corresponding field theory can be renormalized by a simple shift of the
spectral function appearing in the spectral action.
This manuscript provides more details than the shorter companion paper, where
we have used a (formal) quantum action principle to arrive at gauge invariance
of the counterterms. Here, we give in addition an explicit expression for the
gauge propagator and compare to recent results in the literature.Comment: 28 pages; revised version. To appear in CMP. arXiv admin note:
substantial text overlap with arXiv:1101.480
QUINQUESERIALIS QUINQUESERIALIS - SPECIFIC PARASITE OF MUSKRAT, AND ITS INFLUENCE ON SOME HEMATOLOGIC PARAMETERS OF THE HOST
Data on infection of muskrat by trematoda species Quinqueserialis quinqueserialis in the Selenga River Delta are presented in this paper. The indexes of infection of muskrat by parasite in 2011 are similar to those in 1981 and 1982. The study is the first attempt to assess the influence of infestation on structure and. quantity leucocytes of blood of infected muskrat in Lake Baikal basin
Geological-morphological description of the Ishtar Terra (photomap of the Venusian surface sheet B-5)
The main part of the Ishtar Terra east of the Maxwell Montes is covered with systems of areal dislocations of several directions, which are called Parquet. According to the structural patterns these may be divided into: (1) the central stable block; (2) the lesser peripheral blocks separated from the central one by gaps and grabens; (3) the zones of mobilized parquet, whose substance flowed downward at an incline in the directions away from the central block in the form of plastic flows; and (4) the partially parqueted lava sheets. The Maxwell Montes were formed as a result of the collision between the central parquet block and the Lakshmi Planum
Geological-morphological description of the Sedna and Guinevre planitiae on Venus (photomap sheets B-11, B-20, B-21)
Presented are descriptions and maps of the region of Sedna and Guinevra Planitiae--representatives of the largest geological providense on Venus comprised of volcanic rock. Units of different age are isolated and their relations are given, as well as interpretations of proposed mechanisms of formation
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