共查询到20条相似文献,搜索用时 31 毫秒
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Li X. P. Li C. F. Wang L. C. Zhou L. 《International Journal of Theoretical Physics》2019,58(5):1590-1602
The anomalous end modes are generated in a one-dimensional p-wave superconducting wire with second-neighbor couplings and a periodic driving in pairing potential. We show that the driving on the amplitude or the phase of the first-neighbor and second-neighbor pairing potential can both generate conventional end modes and anomalous end modes, with corresponding Floquet eigenvalues equal to ± 1 or appear in complex conjugate pairs. We have numerically studied the driving of the first-neighbor and second-neighbor pairing potential, and also analyzed the end modes, Floquet eigenvalues and the Fourier transform of these end modes.
相似文献3.
Longwen Zhou Hailong Wang Derek Y.H. Ho Jiangbin Gong 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(9):1-13
The recent creation of novel topological states of matter via periodic driving fields has attracted much attention. To contribute to the growing knowledge on this subject, we study the well-known Harper-Aubry-André model modified by a continuous time-periodic modulation and report on its topological properties along with several other interesting features. The Floquet bands are found to have non-zero Chern numbers which are generally different from those in the original static model. Topological phase transitions (discontinuous change of Chern numbers) take place as we tune the amplitude or period of the driving field. We demonstrate that the non-trivial Floquet band topology manifests via the quantized transport of Wannier states in the lattice space. For certain parameter choices, very flat yet topologically non-trivial Floquet bands emerge, a feature potentially useful for simulating the physics of strongly correlated systems. In some cases with an even number of Floquet bands, the spectrum features linearly dispersing Dirac cones which hold potential for the simulation of high energy physics or Klein tunnelling. Taking open boundary conditions, we observe anomalous counter-propagating chiral edge modes and degenerate zero modes. We end by discussing how these theoretical predictions may be verified experimentally. 相似文献
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We consider wave propagation in a model of a deep ocean acoustic wave guide with a periodic range dependence. It is assumed that the wave field is governed by the parabolic equation. Formally the mathematical model of the wave guide coincides with that of a quantum system with time-dependent Hamiltonian. From the analysis of Floquet modes of the wave guide it is shown that there exists a "scarring" effect similar to that observed in quantum systems. It turns out that the segments of an unstable periodic ray trajectory may be distinguished in the spatial distribution of the wave field intensity at a finite wavelength. Besides the scarring effect, it is found that the so-called "stable islands" in the phase space of ray dynamics reveal themselves in the coarse-grained Wigner functions of the Floquet modes. 相似文献
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Ingo Scholz Jacco D. van Beek Matthias Ernst 《Solid state nuclear magnetic resonance》2010,37(3-4):39-59
This article reviews the application of operator-based Floquet theory in solid-state NMR. Basic expressions for calculating effective Hamiltonians based on van Vleck perturbation theory are reviewed for problems with a single frequency or multiple incommensurate frequencies. Such a treatment allows calculation of effective Hamiltonians for resonant and non-resonant problems. Examples from literature are given for single-mode to triple-mode Floquet problems, covering a wide range of applications in solid-state NMR under magic-angle spinning and radio-frequency irradiation of a single nucleus or multiple nuclei. 相似文献
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针对交流激励下电阻-电容分路的约瑟夫森结,采用增量谐波平衡法推导了系统中周期解的解析表达式,并运用Floquet理论分析了周期解的稳定性.发现系统处于稳定周期状态的同时,还存在着丰富的不稳定周期解.通过计算Floquet乘数,得到了系统稳定周期解失稳时的临界参数值,并确定了系统发生的分岔类型,从理论上证明了系统随激励电流幅值的增加由倍周期分岔通向混沌.解析分析与数值计算结果具有很好的一致性.
关键词:
约瑟夫森结
增量谐波平衡法
周期解
分岔 相似文献
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We present explicit expressions for the Floquet states of a periodically kicked particle in coordinate and momentum representations.
These states have been used to evaluate the energy of the particle after an arbitrary number of kicks. 相似文献
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We calculate exactly the two bound Floquet modes of a periodic linear waveguide induced in a medium by a second-order soliton of the nonlinear Schr?dinger equation. The modes are degenerate at the writing frequency, having the same quasi-propagation constant, which suggests applications of our method to spectral filtering. 相似文献
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Mazo JJ 《Physical review letters》2002,89(23):234101
We have proposed theoretically and studied numerically the existence of discrete breathers (intrinsic localized modes) in the dynamics of a two-dimensional Josephson-junction array biased by radio-frequency fields. The solutions are linearly stable in the framework of the Floquet theory and robust in the presence of thermal fluctuations. We have also discussed the conditions for realizing an experimental detection of these modes. 相似文献
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Propagation in perturbed one-dimensional phononic or photonic crystals, with bothcompositional and positional disorder, is considered. The coherent potential approximationis used to obtain the band structure and the Floquet normal form of theperiodic-on-average perturbed crystal, which is modified differently with respect to thetwo kinds of disorder. For finite size crystals, the transmission amplitude is calculatedand compared to direct numerical simulations and to an estimate based on localizationlength. The transmission spectrum is found to be better described using the fullexpression of the Floquet modes of the disordered, but periodic on average, medium. 相似文献
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Periodic structures like Bragg-gratings are important components of optical circuits. The analysis of these devices can be done very efficiently by combining eigenmode propagation methods with Floquet's theorem. A particular problem is the determination of the Floquet modes. Transfer matrix formulas are stable only in case of low losses and when the length of the periods is not too big. A stable method, also in the mentioned cases, is presented in this paper. Reflection coefficients are transformed from the output of a periodic segment to its input and the fields are computed in opposite direction. By this, the exponential increasing terms, which lead to the numerical problems are avoided. The formulas are applied to determine eigenmodes in various waveguide structures. Particular periodic structures are photonic crystals (PC), who have very promising features. For tailoring these PCs the knowledge of the band structure is required. With the Floquet modes that have been determined before this band structure has been calculated. A comparison with the literature showed a very good agreement. 相似文献
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We explore quantum signatures of classical chaos by studying the rate of information gain in quantum tomography. The tomographic record consists of a time series of expectation values of a Hermitian operator evolving under the application of the Floquet operator of a quantum map that possesses (or lacks) time-reversal symmetry. We find that the rate of information gain, and hence the fidelity of quantum state reconstruction, depends on the symmetry class of the quantum map involved. Moreover, we find an increase in information gain and hence higher reconstruction fidelities when the Floquet maps employed increase in chaoticity. We make predictions for the information gain and show that these results are well described by random matrix theory in the fully chaotic regime. We derive analytical expressions for bounds on information gain using random matrix theory for different classes of maps and show that these bounds are realized by fully chaotic quantum systems. 相似文献
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采用等离子体流体模型和线性场理论,导出了在强引导磁场下,一无限薄环形等离子体加载 波纹波导中电磁波传播的色散关系.数值计算并分析了在不同的等离子体填充密度下,低频 等离子体模式的色散特性和行波管的小信号增益.研究发现,低频等离子体模式可与相对论 电子束发生同步互作用使高频信号放大.同时,在无限薄环形等离子体填充条件下,波纹波 导中的低频等离子体模式严格满足Floquet定理所要求的周期性,其上截止频率不再受到等 离子体频率的限制,当密度较大时,等离子体模式还可与TM模式发生耦合.
关键词:
等离子体
波纹波导
色散关系
增益 相似文献
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Nguyen Vinh Quang 《Czechoslovak Journal of Physics》1985,35(1):86-94
Explicit analytical expressions are derived for Floquet states and the quasienergy spectrum of semiconductors with zinc-blende structure and direct band gaps, taking into account the real symmetry properties of the degenerate valence bands.The author would like to thank Academician professor Nguyen Van Hieu for suggesting the problem and for valuable discussions. 相似文献
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L.S. Zhang L. Cai C.W. Feng 《Physica C: Superconductivity and its Applications》2011,471(5-6):150-155
The calculation scheme for periodic solutions in an rf-driven Josephson junction including interference current is derived by using the incremental harmonic balance method. The approximate analytical expressions of stable and unstable periodic orbits are obtained. The stability and bifurcation of the periodic solutions are analyzed based on Floquet theory. The results show that, with the increase of the driving amplitude, one of the periodic solutions undergoes symmetry-breaking and period-doubling bifurcation, which leads to chaos eventually. However, the other periodic solution of the system disappears via a saddle-node bifurcation. 相似文献
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The complex behavior of a reaction-diffusion system is investigated in two dimensions near a
codimension-2 point between a Hopf and a Wave bifurcation with resonant critical modes. As a result of coupling of a (ω, 0)-mode
with modes (ω, k), standing waves arise in an extended region of the control parameters. Near
threshold they appear with hexagonal symmetry. The selected wavenumber and
the competition of two different spatial scales as a function of the control
parameter agree with results calculated from Floquet analysis. 相似文献
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The theory for current fluctuations in ac-driven transport through nanoscale systems is put forward. By use of a generalized, non-Hermitian Floquet theory we derive novel explicit expressions for the time-averaged current and the zero-frequency component of the power spectrum of current fluctuations. A distinct suppression of both the zero-frequency noise and the dc current occurs for suitably tailored ac fields. The relative level of transport noise, being characterized by a Fano factor, can selectively be manipulated by ac sources; in particular, it exhibits both characteristic maxima and minima near current suppression. 相似文献
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De Cupis P 《Optics letters》2003,28(10):849-850
The solution to the problem of optical or electromagnetic-wave scattering from perfectly conducting rough surfaces modeled by a multiscale fractal function is generalized to the case of relative uniform translating motion with respect to the observer. The presence of motion can be treated by the relativistic frame hopping method by means of plane-wave simplification techniques, since the solution relevant to the static case is expressed in terms of a generalized expansion of Floquet modes. 相似文献