4,463 research outputs found
Cornering the unphysical vertex
In the classical pure spinor worldsheet theory of AdS5xS5 there are some
vertex operators which do not correspond to any physical excitations. We study
their flat space limit. We find that the BRST operator of the worldsheet theory
in flat space-time can be nontrivially deformed without deforming the
worldsheet action. Some of these deformations describe the linear dilaton
background. But the deformation corresponding to the nonphysical vertex differs
from the linear dilaton in not being worldsheet parity even. The nonphysically
deformed worldsheet theory has nonzero beta-function at one loop. This means
that the classical Type IIB SUGRA backgrounds are not completely characterized
by requiring the BRST symmetry of the classical worldsheet theory; it is also
necessary to require the vanishing of the one-loop beta-function.Comment: LaTeX 40pp; v2: explained the relation to the linear dilaton
background (Section 6), changes in Introduction and Abstrac
Data availability and data archeology from the former Soviet Union
Acquisition of data on the ocean is believed to start in 1872, when the Royal Navy ship 'Challenger' performed oceanographic stations in its round-world voyage (1872-1876). The first oceanographic studies of the World Ocean refer to the 80s second half of the 19th century. During its round-world expedition 'Vityaz' (1886-1889) headed by S.O. Markov, performed hydrological measurements in the Baltic Sea, Atlantic and Pacific Oceans. According to information available the regular expedition observations (prototype of future complex international program on the ocean research) started in the second half of 80s last century under the auspice of Kiev commission for exploration of German Seas. Systematic hydrological observations were organized by Hydrographic Department of Russia in 1876-1879 according to the program similar to the Kiev one and observations were regularly made by ships of custom service over the Russian area of the Baltic Sea. The increasing demands in oceanographic data contributed to considerable progress in exploration of the World Ocean during current century whole tendency to increase and become more significant has been observed for the last 30-40 years. Most probably various expeditions which were carried out during International Geophysical Year in different regions of the World Ocean are to be reference point in performing intensive oceanographic observations of Marine environment. In the former USSR oceanographic observations are made by research and hydrographic vessels, commercial and fishery ships as well as oil production platforms, coastal hydrometeorological station and other observing platforms. Oceanographic observations data, available from main sources of information on the ocean-research vessels, are also considered in the report
Microwave response of a two-dimensional electron stripe
Electromagnetic response of a finite-width two-dimensional electron stripe is
theoretically studied. It is shown that retardation and radiative effects
substantially modify the absorption spectrum of the system at microwave
frequencies, leading to a non-trivial zigzag behavior of the
magnetoplasmon-polariton modes in magnetic fields, similar to that recently
observed by Kukushkin et al. [Phys. Rev. Lett. {\bf 90}, 156801 (2003)].Comment: 7 pages, 4 figure
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