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Ivanov Y.B.,National Research Nuclear University | Soldatov A.A.,National Research Nuclear University MEPhI
Physical Review C - Nuclear Physics | Year: 2015

The transverse-momentum-integrated elliptic flow of charged particles at midrapidity, v2(charged), and that of identified hadrons from Au+Au collisions are computed in a wide range of incident energies 2.7 ≤sNN≤39 GeV. The simulations are performed within a three-fluid model by employing three different equations of state (EoSs): a purely hadronic EoS and two versions of the EoS involving the deconfinement transition - a first-order phase transition and a smooth crossover one. The present simulations demonstrate low sensitivity of v2(charged) to the EoS. All considered scenarios equally well reproduce recent STAR data on v2(charged) for mid-central Au+Au collisions and properly describe its change of sign at the incident energy decrease below sNN≈3.5 GeV. The predicted integrated elliptic flow of various species exhibits a stronger dependence on the EoS. A noticeable sensitivity to the EoS is found for antibaryons and, to a lesser extent, for K- mesons. In particular, the v2 excitation functions of antibaryons exhibit a nonmonotonicity within the deconfinement scenarios that was predicted by Kolb, Sollfrank, and Heinz. However, low multiplicities of antibaryons at sNN≤10 GeV result in large fluctuations of their v2, which may wash out this nonmonotonicity. © 2015 American Physical Society.

Ivanov Y.B.,National Research Nuclear University | Soldatov A.A.,National Research Nuclear University MEPhI
Physical Review C - Nuclear Physics | Year: 2015

Analysis of directed flow (v1) of protons, antiprotons, and pions in heavy-ion collisions is performed in the range of incident energies sNN=2.7-27 GeV. Simulations have been done within a three-fluid model employing a purely hadronic equation of state (EoS) and two versions of the EoS involving deconfinement transitions: a first-order phase transition and a smooth crossover transition. High sensitivity of the directed flow, especially the proton one, to the EoS is found. The crossover EoS is favored by the most part of considered experimental data. A strong wiggle in the excitation function of the proton v1 slope at the midrapidity obtained with the first-order-phase-transition EoS and a smooth proton v1 with positive midrapidity slope, within the hadronic EoS unambiguously disagree with the data. The pion and antiproton v1 also definitely testify in favor of the crossover EoS. The results obtained with deconfinement EoS's apparently indicate that these EoS's in the quark-gluon sector should be stiffer at high baryon densities than those used in the calculation. © 2015 American Physical Society.

Grigorieva E.V.,Belarusian National Technical University | Kaschenko S.A.,National Research Nuclear University
Physica D: Nonlinear Phenomena | Year: 2015

Dynamics of laser with time-variable delayed feedback is analyzed in the neighborhood of the equilibrium. For the system, averaged over a rapidly variable, we obtain parameters at which the stationary state is stable. Stabilization of the stationary state due to modulation of the delay can be successful (unsuccessful) in domains adjacent to super (sub-) critical Hopf bifurcation boundaries. In a vicinity of the bifurcation points, stable and unstable periodic solutions are asymptotically described in dependence on the modulation frequency. © 2014 Elsevier B.V. All rights reserved.

Elesin V.F.,National Research Nuclear University
Journal of Experimental and Theoretical Physics | Year: 2014

An analytic solution to the problem on transient processes in a two-barrier nanostructure is found. Explicit expressions are obtained for a transient current produced by an instantly applied weak electric field. The current relaxes to a stationary state for a time Latin small letter h with stroke/Γ (Γ is the width of a resonance level), oscillating at a frequency of ξ = Γ - Γ R, where Γ is the energy of electrons coming from an emitter and Γ R is the resonance level energy. The transient current for interacting electrons is found in the quasi-classical approximation. It is shown that interaction between electrons can drastically change the transient current, especially in the presence of hysteresis of the current-voltage characteristic (CVC). Near extreme CVC values in the region of negative differential conductivity, the oscillation frequency tends to zero and becomes imaginary, compensating the decay. Thus, the transient current relaxes with very large times without oscillations. In contrast, in the case of positive differential conductivity, the oscillation frequency becomes very high, while the relaxation time remains the same, 1/Γ. © 2014 Pleiades Publishing, Inc.

Sadykov N.R.,National Research Nuclear University
Technical Physics | Year: 2014

The excitation of the nonlinear medium based on the zigzag nanotubes is analyzed. The terahertz emission is demonstrated under excitation in spite of an equidistant spectrum of a single nanotube. The system exhibits relatively high absorbance in the absence of pumping due to a relatively large oscillator strength. © 2014 Pleiades Publishing, Ltd.

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