scholarly journals Soliton solutions of the 3D Gross-Pitaevskii equation by a potential control method

2010 ◽  
Author(s):  
R. Fedele ◽  
B. Eliasson ◽  
F. Haas ◽  
P. K. Shukla ◽  
D. Jovanović ◽  
...  
Keyword(s):  
Control Method ◽  
Soliton Solutions ◽  
Pitaevskii Equation ◽  
Potential Control

Dynamics of matter-wave solitons in three-component Bose-Einstein condensates with time-modulated interactions and gain or loss effect

2022 ◽  
Author(s):  
Yajie Yang ◽  
Ying Dong
Keyword(s):  
Similarity Transformation ◽  
Soliton Solutions ◽  
Gain Coefficient ◽  
Loss Coefficient ◽  
Matter Wave ◽  
Pitaevskii Equation ◽  
Loss Parameter ◽  
Dynamical Properties ◽  
Bose Einstein ◽  
Loss Effect

Abstract The gain or loss effect on the dynamics of the matter-wave solitons in three-component Bose-Einstein condensates with time-modulated interactions trapped in parabolic external potentials are investigated analytically. Some exact matter-wave soliton solutions to the three-coupled Gross-Pitaevskii equation describing the three-component Bose-Einstein condensates are constructed by similarity transformation. The dynamical properties of the matter-wave solitons are analyzed graphically, and the effects of the gain or loss parameter and the frequency of the external potentials on the matter-wave solitons are explored. It is shown that the gain coefficient makes the atom condensate to absorb energy from the background, while the loss coefficient brings about the collapse of the condensate.

scholarly journals CH4 Adsorption Probability on GaN(0001) and (000−1) during Metalorganic Vapor Phase Epitaxy and Its Relationship to Carbon Contamination in the Films

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 972 ◽  
Author(s):  
Akira Kusaba ◽  
Guanchen Li ◽  
Pawel Kempisty ◽  
Michael von Spakovsky ◽  
Yoshihiro Kangawa
Keyword(s):  
Vapor Phase ◽  
Sequential Analysis ◽  
Chemical Potential ◽  
Control Method ◽  
Metalorganic Vapor Phase Epitaxy ◽  
Vapor Phase Epitaxy ◽  
Impurity Molecule ◽  
Surface Layers ◽  
Carbon Contamination ◽  
Potential Control

Suppression of carbon contamination in GaN films grown using metalorganic vapor phase epitaxy (MOVPE) is a crucial issue in its application to high power and high frequency electronic devices. To know how to reduce the C concentration in the films, a sequential analysis based on first principles calculations is performed. Thus, surface reconstruction and the adsorption of the CH4 produced by the decomposition of the Ga source, Ga(CH3)3, and its incorporation into the GaN sub-surface layers are investigated. In this sequential analysis, the dataset of the adsorption probability of CH4 on reconstructed surfaces is indispensable, as is the energy of the C impurity in the GaN sub-surface layers. The C adsorption probability is obtained based on steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic ensemble-based, non-phenomenological framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium. This framework is suitable especially when one studies the adsorption behavior of an impurity molecule because the conventional approach, the chemical potential control method, cannot be applied to a quantitative analysis for such a system. The proposed sequential model successfully explains the influence of the growth orientation, GaN(0001) and (000−1), on the incorporation of C into the film. This model can contribute to the suppression of the C contamination in GaN MOVPE.

scholarly journals A Simplified Finite Control Set Model Predictive Control for T-Type Three-Level Power Conversion System Based on LCL Filter

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Ning Gao ◽  
Huaiyu Fan ◽  
Weimin Wu
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Method ◽  
Power Conversion ◽  
Lcl Filter ◽  
Potential Control ◽  
Conversion System ◽  
Finite Control ◽  
Control Set ◽  
Battery Energy

Finite control set model predictive control (FCSMPC) is a highly attractive and potential control method for grid-tied converters. However, there are several challenges when employing FCSMPC in an LCL filter-based T-type three-level power conversion system (PCS) for battery energy storage applications. These challenges mainly include the increasing complexity of control algorithm and excessive cost of additional sensors, which deteriorate the performance of PCS and limit the application of FCSMPC. In order to overcome these issues, this paper proposes a simplified FCSMPC algorithm to reduce the computation complexity. Furthermore, full-dimensional state observers are adopted and implemented to estimate the instantaneous values of grid-side current and capacitor voltage for purpose of removing unnecessary electrical sensors. The implementation of proposed FCSMPC algorithm is described step by step in detail. Simulation results are provided as a verification for the correctness of theoretical analysis. Finally, a three-phase T-type three-level PCS prototype rated at 2.30 kVA/110 V is built up. Experimental results extracted from the prototype can verify the effectiveness of the proposed control strategy.

scholarly journals HYDRODYNAMICS OF THE VACUUM

2006 ◽  
Vol 21 (13n14) ◽  
pp. 2877-2903 ◽  
Author(s):  
P. M. STEVENSON
Keyword(s):  
Soliton Solutions ◽  
Empty Space ◽  
Effective Theory ◽  
Pitaevskii Equation ◽  
Hydrodynamic Equations ◽  
Wave Regime ◽  
Hydrodynamic Description ◽  
Normal Medium ◽  
Fluid Medium ◽  
Vacuum Case

Hydrodynamics is the appropriate "effective theory" for describing any fluid medium at sufficiently long length scales. This paper treats the vacuum as such a medium and derives the corresponding hydrodynamic equations. Unlike a normal medium the vacuum has no linear sound-wave regime; disturbances always "propagate" nonlinearly. For an "empty vacuum" the hydrodynamic equations are familiar ones (shallow water-wave equations) and they describe an experimentally observed phenomenon — the spreading of a clump of zero-temperature atoms into empty space. The "Higgs vacuum" case is much stranger; pressure and energy density, and hence time and space, exchange roles. The speed of sound is formally infinite, rather than zero as in the empty vacuum. Higher-derivative corrections to the vacuum hydrodynamic equations are also considered. In the empty-vacuum case the corrections are of quantum origin and the post-hydrodynamic description corresponds to the Gross–Pitaevskii equation. We conjecture the form of the post-hydrodynamic corrections in the Higgs case. In the (1+1)-dimensional case the equations possess remarkable "soliton" solutions and appear to constitute a new exactly integrable system.

scholarly journals Harmonic Analysis and Neutral-Point Potential Control of Interleaved Parallel Three-Level Inverters for Flywheel Energy Storage System

2022 ◽  
Vol 9 ◽  
Author(s):  
Zhongrui Li ◽  
Ziling Nie ◽  
Jie Xu ◽  
Huayu Li ◽  
Sheng Ai
Keyword(s):  
Energy Storage ◽  
Harmonic Analysis ◽  
Control Method ◽  
Storage System ◽  
Energy Storage System ◽  
Neutral Point ◽  
Flywheel Energy Storage System ◽  
Potential Control ◽  
Point Potential ◽  
Analysis Models

Flywheel energy storage system is a popular energy storage technology, in which inverters are the center of electrical energy conversion, directly affecting the power capacity. Parallel operation of three-level inverters is an effective approach to achieve larger motor drive power and the interleaved operation can improve the harmonic characteristics. However, harmonic analysis models of the interleaved parallel three-level inverters are rare in the literature and how the neutral-point potential imbalance affects the harmonics characteristics has not been discussed. This article establishes the harmonic calculation for balanced and unbalanced neutral-point potential through the five-level voltage capability of the interleaved parallel three-level inverters. Moreover, a neutral-point potential control method based on zero-sequence voltage injection is proposed. The implement process of the method is proposed, and how the operating frequency affect the ability of the neutral-point potential balance is studied. Finally, the simulation and experiment results verify the feasibility and practicability of the established harmonic analysis models and the neutral-point potential control method.

scholarly journals Soliton Solutions and Collisions for the Multicomponent Gross–Pitaevskii Equation in Spinor Bose–Einstein Condensates

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ming Wang ◽  
Guo-Liang He
Keyword(s):  
Soliton Solutions ◽  
Auxiliary Function ◽  
Einstein Condensate ◽  
Polarization Parameter ◽  
One Dimension ◽  
Pitaevskii Equation ◽  
Bose Einstein Condensate ◽  
The One ◽  
Bose Einstein ◽  
Two Peaks

In this paper, we investigate a five-component Gross–Pitaevskii equation, which is demonstrated to describe the dynamics of an F=2 spinor Bose–Einstein condensate in one dimension. By employing the Hirota method with an auxiliary function, we obtain the explicit bright one- and two-soliton solutions for the equation via symbolic computation. With the choice of polarization parameter and spin density, the one-soliton solutions are divided into four types: one-peak solitons in the ferromagnetic and cyclic states and one- and two-peak solitons in the polar states. For the former two, solitons share the similar shape of one peak in all components. Solitons in the polar states have the one- or two-peak profiles, and the separated distance between two peaks is inversely proportional to the value of polarization parameter. Based on the asymptotic analysis, we analyze the collisions between two solitons in the same and different states.

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