557 research outputs found
Nonrenormalization Theorem for Gauge Coupling in 2+1D
We prove that \be-function of the gauge coupling in gauge theory
coupled to any renormalizable system of spinor and scalar fields is zero. This
result holds both when the gauge field action is the Chern-Simons action and
when it is the topologically massive action.Comment: 8 pages, LaTeX file, CALT-68-191
In situ determination of the energy dependence of the high-frequency mobility in polymers
The high-frequency mobility in disordered systems is governed by transport
properties on mesoscopic length scales, which makes it a sensitive probe for
the amount of local order. Here we present a method to measure the energy
dependence of the high frequency mobility by combining an electrochemically
gated transistor with in-situ quasi-optical measurements in the sub-terahertz
domain. We apply this method to
poly([2-methoxy-5-(3',7'-dimethylocyloxy)]-p-phenylene vinylene) (OC_1C_10-PPV)
and find a mobility at least as high as 0.1 cm^2V^-1s^-1.Comment: 3 pages (incl. 3 figures) in Appl. Phys. Let
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
Optical conductivity and penetration depth in MgB2
The complex conductivity of a MgB2 film has been investigated in the
frequency range 4 cm^{-1}< nu < 30 cm^{-1} and for temperatures 2.7 K < T <300
K. The overall temperature dependence of both components of the complex
conductivity is reminiscent of BCS-type behavior, although a detailed analysis
reveals a number of discrepancies. No characteristic feature of the isotropic
BCS gap temperature evolution is observed in the conductivity spectra in the
superconducting state. A peak in the temperature dependence of the real part of
the conductivity is detected for frequencies below 9 cm^{-1}. The
superconducting penetration depth follows a T^2 behavior at low temperatures.Comment: 4 pages, 4 figure
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
Non-Renormalization Theorem for the Gauge Coupling in 2+1 Dimensions
We prove that the β-function of the gauge coupling in 2+1 dimensions gauge theory coupled to any renormalizable system of spinor and scalar fields is zero. This result holds both when the gauge field action is the Chern-Simons action and when it is the topologically massive action
Polarization control of direct (non-sequential) two-photon double ionization of He
An ab initio parametrization of the doubly-differential cross section (DDCS) for two-photon double ionization (TPDI) from an s2 subshell of an atom in a 1S0-state is presented. Analysis of the elliptic dichroism (ED) effect in the DDCS for TPDI of He and its comparison with the same effect in the concurrent process of sequential double ionization shows their qualitative and quantitative differences, thus providing a means to control and to distinguish sequential and non-sequential processes by measuring the relative ED parameter
Spin excitations of the correlated semiconductor FeSi probed by THz radiation
By direct measurements of the complex optical conductivity of
FeSi we have discovered a broad absorption peak centered at frequency
that develops at temperatures below 20 K.
This feature is caused by spin-polaronic states formed in the middle of the gap
in the electronic density of states. We observe the spin excitations between
the electronic levels split by the exchange field of . Spin
fluctuations are identified as the main factor determining the formation of the
spin polarons and the rich magnetic phase diagram of FeSi.Comment: 5 pages, 4 figure
The structure of the exact effective action and the quark confinement in MSSM QCD
An expression for the exact (nonperturbative) effective action of =1
supersymmetric gauge theories is proposed, supposing, that all particles except
for the gauge bosons are massive. Analysis of its form shows, that instanton
effects in the supersymmetric theories can lead to the quark confinement. The
typical scale of confinement in MSSM QCD, calculated from the first principles,
is in agreement with the experimental data. The proposed explanation is quite
different from the dual Higgs mechanism.Comment: Final version to appear in Sov.J.Nucl.Phys. Some insignificant errors
and misprints are correcte
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