1,679 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
The Effect of Mechanical Resonance on Josephson Dynamics
We study theoretically dynamics in a Josephson junction coupled to a
mechanical resonator looking at the signatures of the resonance in d.c.
electrical response of the junction. Such a system can be realized
experimentally as a suspended ultra-clean carbon nanotube brought in contact
with two superconducting leads. A nearby gate electrode can be used to tune the
junction parameters and to excite mechanical motion. We augment theoretical
estimations with the values of setup parameters measured in the samples
fabricated.
We show that charging effects in the junction give rise to a mechanical force
that depends on the superconducting phase difference. The force can excite the
resonant mode provided the superconducting current in the junction has
oscillating components with a frequency matching the resonant frequency of the
mechanical resonator. We develop a model that encompasses the coupling of
electrical and mechanical dynamics. We compute the mechanical response (the
effect of mechanical motion) in the regime of phase bias and d.c. voltage bias.
We thoroughly investigate the regime of combined a.c. and d.c. bias where
Shapiro steps are developed and reveal several distinct regimes characteristic
for this effect. Our results can be immediately applied in the context of
experimental detection of the mechanical motion in realistic superconducting
nano-mechanical devices.Comment: 18 pages, 11 figure
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
Development of the Vychegda-Vyatka-Kama drainage basin and changes in the outflow directions related to the Late-Glacial morphological conditions (North-Eastern European Russia)
The paper describes the features of the drainage system development in the upper Kama basin. Two buried river valleys were identified within the Kama-Pechora-Vychegda watershed. The upper courses of the Kama, the Vychegda, the Pechora and their tributaries likely belonged either to the White Sea basin, or the Caspian Basin. The southern direction of the outflow corresponded to the location of the palaeovalleys of the Pra-Kolva and the Pra-Vishera. The northern direction corresponded to the location of ancient hollows in the present valleys of the tributaries of the Kama. It is believed that the upper Kama was connected with the Vychegda basin. The geological structure of the palaeovalley has recorded a long period of joint development of the hydrosystems of the Kama and the Vyatka. The basins were divided only in the Late Neo-Pleistocene. The rivers regenerated in the Middle and Late Neo-Pleistocene after the lakes had flowed into the Kolva-Vishera basin in the east and into the Pra-Vyatka basin in the west
Factorial cumulants reveal interactions in counting statistics
Full counting statistics concerns the stochastic transport of electrons in
mesoscopic structures. Recently it has been shown that the charge transport
statistics for non-interacting electrons in a two-terminal system is always
generalized binomial: it can be decomposed into independent single-particle
events and the zeros of the generating function are real and negative. Here we
investigate how the zeros of the generating function move into the complex
plane due to interactions and demonstrate that the positions of the zeros can
be detected using high-order factorial cumulants. As an illustrative example we
consider electron transport through a Coulomb blockade quantum dot for which we
show that the interactions on the quantum dot are clearly visible in the
high-order factorial cumulants. Our findings are important for understanding
the influence of interactions on counting statistics and the characterization
in terms of zeros of the generating function provides us with a simple
interpretation of recent experiments, where high-order statistics have been
measured.Comment: 12 pages, 7 figures, Editors' Suggestion in Phys. Rev.
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