1,227 research outputs found
Irreducibility of fusion modules over twisted Yangians at generic point
With any skew Young diagram one can associate a one parameter family of
"elementary" modules over the Yangian \Yg(\g\l_N). Consider the twisted
Yangian \Yg(\g_N)\subset \Yg(\g\l_N) associated with a classical matrix Lie
algebra \g_N\subset\g\l_N. Regard the tensor product of elementary Yangian
modules as a module over \Yg(\g_N) by restriction. We prove its
irreducibility for generic values of the parameters.Comment: Replaced with journal version, 18 page
On irreducibility of tensor products of evaluation modules for the quantum affine algebra
Every irreducible finite-dimensional representation of the quantized
enveloping algebra U_q(gl_n) can be extended to the corresponding quantum
affine algebra via the evaluation homomorphism. We give in explicit form the
necessary and sufficient conditions for irreducibility of tensor products of
such evaluation modules.Comment: 22 pages. Some references are adde
Statistics of Transmission Eigenvalues for a Disordered Quantum Point Contact
We study the distribution of transmission eigenvalues of a quantum point
contact with nearby impurities. In the semi-classical case (the chemical
potential lies at the conductance plateau) we find that the transmission
properties of this system are obtained from the ensemble of Gaussian random
reflection matrices. The distribution only depends on the number of open
transport channels and the average reflection eigenvalue and crosses over from
the Poissonian for one open channel to the form predicted by the circuit theory
in the limit of large number of open channels.Comment: 8 pages, 3 figure
Tunnelling density of states at Coulomb blockade peaks
We calculate the tunnelling density of states (TDoS) for a quantum dot in the
Coulomb blockade regime, using a functional integral representation with
allowing correctly for the charge quantisation. We show that in addition to the
well-known gap in the TDoS in the Coulomb-blockade valleys, there is a
suppression of the TDoS at the peaks. We show that such a suppression is
necessary in order to get the correct result for the peak of the differential
conductance through an almost close quantum dot.Comment: 6 pages, 2 figure
Zero bias anomaly in a two dimensional granular insulator
We compare tunneling density of states (TDOS) into two ultrathin Ag films,
one uniform and one granular, for different degrees of disorder. The uniform
film shows a crossover from Altshuler-Aronov (AA) zero bias anomaly to Efros
Shklovskii (ES) like Coulomb gap as the disorder is increased. The granular
film, on the other hand, exhibits AA behavior even deeply in the insulating
regime. We analyze the data and find that granularity introduces a new regime
for the TDOS. While the conductivity is dominated by hopping between clusters
of grains and is thus insulating, the TDOS probes the properties of an
individual cluster which is "metallic".Comment: 4 pages, 4 figure
Josephson effect in SXS junctions
We investigate the Josephson effect in SXS junctions,
where S is a superconducting material with a ferromagnetic exchange
field, and X a weak link. The critical current increases with the
(antiparallel) exchange fields if the distribution of transmission eigenvalues
of the X-layer has its maximum weight at small values. This exchange field
enhancement of the supercurrent does not exist if X is a diffusive normal
metal. At low temperatures, there is a correspondence between the critical
current in an SIS junction with collinear orientations of
the two exchange fields, and the AC supercurrent amplitude in an SIS tunnel
junction. The difference of the exchange fields in an SIS junction corresponds to the potential difference in
an SIS junction; i.e., the singularity in [in an SIS
junction] at is the analogue of the Riedel peak.
We also discuss the AC Josephson effect in SIS junctions.Comment: 5 pages, 5 figure
РАСЧЕТ ПОЛНОТЫ РЕАКЦИЙ И ПРЕВРАЩЕНИЯ ВЕЩЕСТВ ПРИ ВОДОУГОЛЬНОЙ ГАЗИФИКАЦИИ
Process of water-coal gasification is satisfactorily described by three thermal and chemical equations; using these equations composition of gasification product (water carbon monoxide gas) has been calculated in accordance with a temperature. Results of the calculations are presented in the form of charts. Процесс водоугольной газификации удовлетворительно описывается тремя термохимическими уравнениями, по которым рассчитан состав продукта газификации (водородоугарного газа) в зависимости от температуры. Результаты расчета представлены в виде графиков
- …