共查询到17条相似文献,搜索用时 93 毫秒
1.
Bifurcation,chaotic phenomena and control of chaos in a one—dimensional discrete Josephson lattice 下载免费PDF全文
We have investigated the fluxon dynamical behaviour in a one-dimensional parallel array of small Josephson junctions in the presence of an externally applied magnetic field. In the case of high damping,the system is in stable state. On the contrary, in the case of low damping, bifurcation and chaotic phenomena have been observed. Control of chaos is achieved by a delayed feedback mechanism, which drives the chaotic system into a selected unstable periodic orbit embadded within the associated strange attractor. It is attractive to control chaos to a periodic state, rather than operating always outside the device parameter space where chaos dominates. 相似文献
2.
Periodic, Quasiperiodic and Chaotic Discrete Breathers in a Parametrical Driven Two-Dimensional Discrete Klein-Gordon Lattice 下载免费PDF全文
We study a two-dimensional lattice of anharmonic oscillators with only quartic nearest-neighbor interactions, in which discrete breathers can be explicitly constructed by an exact separation of their time and space dependence. DBs can stably exist in the two-dimensional Klein-Gordon lattice with hard on-site potential. When a parametric driving term is introduced in the factor multiplying the harmonic part of the on-site potential of the system, we can obtain the stable quasiperiodic discrete breathers and chaotic discrete breathers by changing the amplitude of the driver. 相似文献
3.
We study the features of a single q-breather (SQB) in a Fermi-Pasta-Ulam lattice by the numerical method, and obtain that the stability of SQB correlates to coupling constant K and nonlinear parameter β. No matter whether K or β increases, the periodic SQB can be transformed into a quasiperiodic SQB or a chaotic SQB. We also obtain the conditions of excitation of periodic, quasiperiodic and chaotic SQBs. 相似文献
4.
XU Quan TIAN Qiang 《理论物理通讯》2009,51(1):153-156
We restrict our attention to the discrete two-dimensional monatomic β-FPU lattice. We look for two- dimensional breather lattice solutions and two-dimensional compact-like discrete breathers by using trying method and analyze their stability by using Aubry's linearly stable theory. We obtain the conditions of existence and stability of two-dimensional breather lattice solutions and two-dimensional compact-like discrete breathers in the discrete two- dimensional monatomic β-FPU lattice. 相似文献
5.
We investigate the unconventional Landau levels of ultracold fermionic atoms on the two-dimensional honeycomb optical lattice subjected to an effective magnetic field, which is created with optical means. In the presence of the effective magnetic field, the energy spectrum of the unconventional Landau levels is calculated. Furthermore, we propose to detect the unconventional Landau levels with Bragg scattering techniques. 相似文献
6.
早期关于二维磁流体力学方程组的描述都是在Lagrangian或Eulerian坐标内进行的。在Lagrangian描述中,计算网格固定在物体上随物体一起运动,网格点与物质点在物体的变形过程中始终保持一致,因此能准确描述物体的移动界面。但对于大变形问题,物质的扭曲将导致计算网格的畸形而使计算无法进行下去。在Eulerian描述中,网格固定在空间中,因而计算网格在物体的变形过程中保持不变,因此很容易处理物质的扭曲。但对于运动界面,需要引入非常复杂的数学映射,将可能导致较大的误差。 相似文献
7.
戴自换 《工程物理研究院科技年报》2009,(1):55-56
靶球在辐射驱动下内爆的物理过程是惯性约束聚变(ICF)研究的重要组成部分之一。由于流场的大变形和物理力学过程的复杂性,相关的数值模拟具有相当大的难度。根据研究工作的需求,符尚武等人克服了数值模拟方法上的重重困难,研制成功了二维三温流体动力学程序-LARED-I第一版。该程序是ICF数值模拟中主要的大型程序之一,在应用中取得了多方面的成果。 相似文献
8.
Periodic, quasiperiodic and chaotic discrete breathers in a parametrical driven two-dimensional discrete diatomic Klein--Gordon lattice 下载免费PDF全文
We study a two-dimensional (2D) diatomic lattice of anharmonic
oscillators with only quartic nearest-neighbor interactions, in
which discrete breathers (DBs) can be explicitly constructed by an
exact separation of their time and space dependence. DBs can stably
exist in the 2D discrete diatomic Klein--Gordon lattice with hard
and soft on-site potentials. When a parametric driving term is
introduced in the factor multiplying the harmonic part of the
on-site potential of the system, we can obtain the stable
quasiperiodic discrete breathers (QDBs) and chaotic discrete
breathers (CDBs) by changing the amplitude of the driver. But the
DBs and QDBs with symmetric and anti-symmetric profiles that are
centered at a heavy atom are more stable than at a light atom,
because the frequencies of the DBs and QDBs centered at a heavy atom
are lower than those centered at a light atom. 相似文献
9.
We analytically and numerically study a 1 D tight-binding model with tunable incommensurate potentials.We utilize the self-dual relation to obtain the critical energy,namely,the mobility edge.Interestingly,we analytically demonstrate that this critical energy is a constant independent of strength of potentials.Then we numerically verify the analytical results by analyzing the spatial distributions of wave functions,the inverse participation rate and the multifractal theory.All numerical results are in excellent agreement with the analytical results.Finally,we give a brief discussion on the possible experimental observation of the invariable mobility edge in the system of ultracold atoms in optical lattices. 相似文献
10.
The properties of discrete breathers in dissipative one-dimensional lattices of nonlinear oscillators subject to periodic driving forces are reviewed. We focus on oscillobreathers in the Frenkel-Kontorova chain and rotobreathers in a ladder of Josephson junctions. Both types of exponentially localized solutions are easily obtained numerically using adiabatic continuation from the anticontinuous limit. Linear stability (Floquet) analysis allows the characterization of different types of bifurcations experienced by periodic discrete breathers. Some of these bifurcations produce nonperiodic localized solutions, namely, quasiperiodic and chaotic discrete breathers, which are generally impossible as exact solutions in Hamiltonian systems. Within a certain range of parameters, propagating breathers occur as attractors of the dissipative dynamics. General features of these excitations are discussed and the Peierls-Nabarro barrier is addressed. Numerical scattering experiments with mobile breathers reveal the existence of two-breather bound states and allow a first glimpse at the intricate phenomenology of these special multibreather configurations. 相似文献
11.
Quantum Ising models in a transverse field are related to continuous-time percolation processes whose oriented percolation versions are contact processes. We study such models in the presence of quasiperiodic disorder and prove localization in the ground state, no percolation, and extinction, respectively, for sufficiently large disorder. 相似文献
12.
Mobility edges and reentrant localization in one-dimensional dimerized non-Hermitian quasiperiodic lattice 下载免费PDF全文
《中国物理 B》2021,30(9):97202-097202
The mobility edges and reentrant localization transitions are studied in one-dimensional dimerized lattice with nonHermitian either uniform or staggered quasiperiodic potentials.We find that the non-Hermitian uniform quasiperiodic disorder can induce an intermediate phase where the extended states coexist with the localized ones,which implies that the system has mobility edges.The localization transition is accompanied by the PT symmetry breaking transition.While if the non-Hermitian quasiperiodic disorder is staggered,we demonstrate the existence of multiple intermediate phases and multiple reentrant localization transitions based on the finite size scaling analysis.Interestingly,some already localized states will become extended states and can also be localized again for certain non-Hermitian parameters.The reentrant localization transitions are associated with the intermediate phases hosting mobility edges.Besides,we also find that the non-Hermiticity can break the reentrant localization transition where only one intermediate phase survives.More detailed information about the mobility edges and reentrant localization transitions are presented by analyzing the eigenenergy spectrum,inverse participation ratio,and normalized participation ratio. 相似文献
13.
Maria Serra 《Journal of statistical physics》1986,42(5-6):961-977
We study the scattering of radiation by a medium presenting inhomogeneities distributed in a quasiperiodic way. We show the existence of quasiperiodic solutions of the two-dimensional stationary wave equation, under certain conditions on the index of refraction, using a technique based on Dinaburg-Sinai method for one-dimensional Schrödinger equation with a quasiperiodic potential. Moreover we show that the energy spctrum contains a nonempty absolutely continuous component, with a subset having high degeneracy, provided the inhomogeneities are small enough. 相似文献
14.
15.
In this paper we study the existence and stability of two-dimensional discrete gap
breathers in a two-dimensional diatomic face-centered square lattice
consisting of alternating light and heavy atoms, with on-site
potential and coupling potential. This study is focused on
two-dimensional breathers with their frequency in the gap that
separates the acoustic and optical bands of the phonon spectrum. We
demonstrate the possibility of the existence of two-dimensional gap
breathers by using a numerical method. Six types of two-dimensional
gap breathers are obtained, i.e., symmetric, mirror-symmetric and
asymmetric, whether the center of the breather is on a light or a
heavy atom. The difference between one-dimensional discrete gap
breathers and two-dimensional discrete gap breathers is also
discussed. We use Aubry's theory to analyze the stability of
discrete gap breathers in the two-dimensional diatomic face-centered
square lattice. 相似文献
16.
A new dynamical system based on Thomas' system is described with infinitely many strange attractors on a 3-D spatial lattice. The mechanism for this multistability is associated with the disturbed offset boosting of sinusoidal functions with different spatial periods. Therefore, the initial condition for offset boosting can trigger a bifurcation, and consequently infinitely many attractors emerge simultaneously. One parameter of the sinusoidal nonlinearity can increase the frequency of the second order derivative of the variables rather than the first order and therefore increase the Lyapunov exponents accordingly. We show examples where the lattice is periodic and where it is quasiperiodic, that latter of which has an infinite variety of attractor types. 相似文献