4,791 research outputs found
On the electric charge of quantized vortices and the dipole moment of vortex pairs and rings in a magnetic field
It is shown that, in the presence of a magnetic field, a quantized vortex
line in a superfluid liquid acquires a linear polarization charge, which is
localized near the vortex axis over a length on the order of the coherence
length. It is found that the total charge of a rectilinear vortex is nonzero,
while the vortex pair and vortex ring have a nonzero dipole moment. The
electric fields of rectilinear vortices near the end surface of a cylindrical
vessel filled with a superfluid liquid are calculated. The electric
polarization of superfluid systems in the presence of thermally activated
vortex pairs and vortex rings has been studied. It is shown that such a
polarization arises in the presence of relative motion of the normal and
superfluid components.Comment: 16 pages, 3 figure
Simulation of the software-defined network for a high-performance computing cluster
The study considers the issues of using the software-defined networks, the current state of the research trends in this area and the most significant projects. The simulation of a high-performance computer network for increase in the performance of the university computing cluster due to the optimization of topology and network traffic between the computational nodes is describe
Causal signal transmission by quantum fields. IV: The causal Wick theorem
Wick's theorem in the Schwinger-Perel-Keldysh closed-time-loop formalism is
written in a form where the place of contractions is taken by the linear
response function of the field. This result demonstrates that the physical
information supplied by Wick's theorem for operators is propagation of the free
field in space and time.Comment: Final version, to appear in Phys Rev
Mathematical model of message delivery in a mobile ad hoc network
Analytic expressions for calculating the average time for delivery of a message, taking into account the effect of subscriber mobility and destructive factors are obtained. The effect of premature discontinuities of virtual connections on the efficiency of data delivery is studie
Model of neuro-fuzzy prediction of confirmation timeout in a mobile ad hoc network
This article represents an RTT prediction model based on application of fuzzy neural network theory. This model relies upon zeroorder Sugeno-Type Fuzzy Inference algorith
Tunneling-assisted impact ionization fronts in semiconductors
We propose a novel type of ionization front in layered semiconductor
structures. The propagation is due to the interplay of band-to-band tunneling
and impact ionization. Our numerical simulations show that the front can be
triggered when an extremely sharp voltage ramp () is
applied in reverse direction to a Si structure that is connected in
series with an external load. The triggering occurs after a delay of 0.7 to 0.8
ns. The maximal electrical field at the front edge exceeds .
The front velocity is 40 times faster than the saturated drift velocity
. The front passes through the base with a thickness of
within approximately 30 ps, filling it with dense electron-hole plasma. This
passage is accompanied by a voltage drop from 8 kV to dozens of volts. In this
way a voltage pulse with a ramp up to can be applied to the
load. The possibility to form a kilovolt pulse with such a voltage rise rate
sets new frontiers in pulse power electronics.Comment: 12 pages, 6 figure
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