On the first Townsend coefficient at high electric field

Based on the simplified approach it is shown and experimentally confirmed that gas gain in wire chambers at very low pressure becomes higher on thicker wires at the same applied high voltage. This is a consequence of the fact that the first Townsend coefficient at high reduced electric field depends almost entirely on the mean free path of electrons.Comment: 10 pages, 3 figures; version 2: revised, a few references adde

N=2 minimal conformal field theories and matrix bifactorisations of x^d

We establish an action of the representations of N=2-superconformal symmetry on the category of matrix factorisations of the potentials x^d and x^d-y^d for d odd. More precisely we prove a tensor equivalence between (a) the category of Neveu–Schwarz-type representa-tions of the N = 2 minimal super vertex operator algebra at central charge 3–6/d, and (b) a full subcategory of graded matrix factorisations of the potential x^d − y^d . The subcategory in (b) is given by permutation-type matrix factorisations with consecutive index sets. The physical motivation for this result is the Landau–Ginzburg/conformal field theory correspondence, where it amounts to the equivalence of a subset of defects on both sides of the correspondence. Our work builds on results by Brunner and Roggenkamp [BR], where an isomorphism of fusion rules was established

Atomic States Entanglement in Carbon Nanotubes

The entanglement of two atoms (ions) doped into a carbon nanotube has been investigated theoretically. Based on the photon Green function formalism for quantizing electromagnetic field in the presence of carbon nanotubes, small-diameter metallic nanotubes are shown to result in a high degree of the two-qubit atomic entanglement for long times due to the strong atom-field coupling.Comment: 4 pages, 2 figure

Taxonomy, Nomenclature, and Evolution of the Early Schubertellid Fusulinids

The types of the species belonging to the fusulinid genera Schubertella and Eoschubertella were examined from publications and type collections. Eoschubertella in general possesses all the features of Schubertella and therefore is a junior synonym of the latter. However, the concept of Eoschubertella best describes the genus Schubertina with its type species Schubertina curculi. Schubertina is closely related to the newly established genus Grovesella the concept of which is emended in this paper. Besides Schubertella, Schubertina, and Grovesella, the genera Mesoschubertella, Biwaella are reviewed and three new species, Grovesella nevadensis, Biwaella zhikalyaki, and Biwaella poletaevi, are described. The phylogenetic relationships of all Pennsylvanian—Cisuralian schubertellids are also proposed. Barrel-shaped Grovesella suggested being the very first schubertellid that appears sometimes in the middle—late Bashkirian time. In late Bashkirian it is then developed into ovoid to fusiform Schubertina. The latter genus gave rise into Schubertella in early Moscovian. First Fusiella derived from Schubertella in late Moscovian, Biwaella—in early Gzhelian and Boultonia—in late Gzhelian time. Genus Mesoschubertella also developed from Schubertella at least in Artinskian, but may be in late Sakmarian

Directed current in the Holstein system

We propose a mechanism to rectify charge transport in the semiclassical Holstein model. It is shown that localised initial conditions, associated with a polaron solution, in conjunction with a nonreversion symmetric static electron on-site potential constitute minimal prerequisites for the emergence of a directed current in the underlying periodic lattice system. In particular, we demonstrate that for unbiased spatially localised initial conditions, violation of parity prevents the existence of pairs of counter-propagating trajectories, thus allowing for a directed current despite the time-reversibility of the equations of motion. Occurrence of long-range coherent charge transport is demonstrated

Discovery of Shallow-Marine Biofacies Conodonts in a Bioherm Within the Carboniferous-Permian Transition in the Omalon Massif, NE Russia near the North Paleo-Pole: Correlation with a Warming Spike in the Southern Hemisphere

The conodont genera Hindeodus and Streptognathodus are reported for the first time within the Carboniferous-Permian transition in the northern high latitudes of the Paren’ River, Omolon Massif, NE Russia. Several fossil groups, including brachiopods, bivalves, scaphopods and microgastropods were found to be prolific in the invertebrate-dominated bioherms. These bioherms occur within predominantly siliciclastic sequences with extremely poor fauna, whereas in the studied bioherms the diversity of the bivalves and brachiopods exceeded observed diversity elsewhere in coeval facies in NE Russia. The bioherms are biostratigraphically constrained as uppermost Pennsylvanian to lowermost Cisuralian based on ammonoids. The very unusual peak of bivalve and brachiopod diversity and the occurrence of conodonts that require minimum sea water temperatures of at least 10-12 °C indicate a short lived, but significant warming event at that time, at least of provincial significance. This event most likely corresponds with a short-lived warming event recently discovered in the east of the southern hemisphere, in Timor and Australia. Thus, the event is possibly of global significance

Laboratory device for demonstration electric and magnetic crosstalk in the cable lines

Проведены измерения емкостной и индуктивной связи в кабельных линиях. Стенд для измерений емкостной и индуктивной связи состоит из двух близкорасположенных кабеля: источника и рецептора помех. Источник помех подключен к генератору NI PXI–5421. Кабель-рецептор нагружен на переменный резистор 500 Ом. Первый канал осциллографа подключен к кабелю — источнику помех, второй к кабелю-рецептору. Величина емкостной и индуктивной связи оценивается коэффициентом передачи. Коэффициент передачи равен отношению амплитуды напряжения на кабеле-рецепторе к напряжению на кабеле-источнике. Для изучения влияния сопротивления нагрузки на величину емкостной и индуктивной связи измерения проводились при минимальном и максимальном положении переменного резистора. В результате проведенных измерений было установлено, что увеличение нагрузки на кабеле-рецепторе приводит к увеличению коэффициента передачи.We have done the measures of electric and magnetic crosstalk in the cable lines. Laboratory device for measurement consists of two closely spaced cable: the source and receptor interference. The source of interference is connected to the generator NI PXI-5421. Receptor of interference is connected to a variable resistor 500 ohms. The first channel oscilloscope is connected to the source of interference, the second is connected to the receptor. The value of electric and magnetic crosstalk is estimated by transmission coefficient. Transfer coefficient is equal relation of the voltage amplitude on the cable-receptor, to the voltage amplitude on the cable-source. Measurements were performed at the minimum and maximum position of the variable resistor. As a result of measurement, it was found that the load increasing on the cable-receptor leads to the increase of the transmission coefficient