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1.
采用二维谐振子相干态为初始态,在形变原子核系统分别为规则和混沌两种情况下,对其在相空间中的时间行为进行了傅里叶分析,特别比较了混沌系统中波包宽度在整个时间段与达到饱和后两个阶段的傅里叶分析结果.指出系统的混沌运动是由于大量能级免交叉的出现在波包运动的初始阶段就破坏了波包内部的规则结构,波包各成分间的协同性被破坏,波包的运动成为混沌.此后,波包内各成分对波包运动的贡献开始相同,能级之间的免交叉对波包运动的影响也不再明显. 相似文献
2.
用数值方法研究了一耦合自旋模型的最近邻能级间距涨落和能级随参数变化曲线的免交叉行为。计算结果表明,当变化参数,系统的经典运动出现从规则→混沌→规则的转变时,间距涨落分布P(s)的Brody参数很好地反映了混沌区域在相空间中占据的比例。在有大量混沌运动的参数范围里,计算观察到了大量的免交叉及它们的重叠,并且能级曲线图呈现相对无规的形貌。这些结果被看作经典混沌在量子能谱中的表现或痕迹。
关键词: 相似文献
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我们利用非绝热相关方法 ,通过关闭所有的振动模式间的耦合项并追溯到零级本征态 ,以得到体系的形式量子数 ,将形式量子数对高激发振动态的能级谱图进行归属 ,并重构本征能级图谱 ,使本征能级以有序的方式排列。这有助于对高激发振动态的能级进行分类和归属。形式量子数是体现高激发振动态的重要特征 ,是高激发振动态的近似运动守恒量。我们将多维陪集相空间的经典方法应用于高激发态的研究 ,发现形式量子数对应的李雅普诺夫指数为零或最小 ,并且它对应于较大的相空间密度 相似文献
5.
用自洽方程模拟了波-粒相互作用过程中的电子混沌行为.结果表明:随着电流的增大,电子在相空间的运动轨道将变得混沌,混沌轨道受失谐量的影响.在时间上,电子混沌比场的极限环和混沌振荡出现要早.与场出现极限环振荡的电流阈值相比,出现电子混沌的电流阈值要小;在场呈极限环状态的“软”非线性区域,电子的混沌轨道占据大部分相空间;而在场混沌的“硬”非线性区域,混沌轨道则弥漫在整个相空间.当电流一定时,电子的混沌运动图样是不变的;在一定的电流范围内, 场的极限环和混沌振荡特征是确定的, 但它们的输出功率是不确定的.
关键词:
行波管放大器
电子混沌
相空间轨道
非线性相互作用 相似文献
6.
非旋波近似条件下Dicke模型表现为量子混沌动力学特征.在详细考察Dicke模型经典相空间结构特点的基础上,采用经典-量子"一对多"的思想,即经典相空间中的一点对应于量子体系两个初始相干态的演化,利用对两个初态量子纠缠动力学演化取统计平均的方法,得到了与经典相空间对应非常好的量子相空间结构.数值计算结果表明:经典混沌有利地促进系统两体纠缠的产生,平均纠缠可以作为量子混沌的标识,利用平均纠缠可以得到一种较好的量子动力学与经典相空间的对应关系.
关键词:
Dicke模型
非旋波近似
量子混沌
经典量子对应 相似文献
7.
本文评述了高技术项目之一自由电子激光(下文中简记为FEL)中的混沌问题。着重讨论了FEL中电子运动和光场发展的不稳定性与混沌现象,以及电子相空间运动轨道的混沌与光场混沌的控制、利用等。在讨论过程中,利用了混沌理论研究中的一些典型方法,如作Poincare截面,画电子的相空间运动轨道,计算Lia-punov指数,作功率谱等。从而揭示FEL中各种稳定、不稳定、及混沌等现象的内在规律性。最后,针对探索FEL的新概念、FEL技术的发展等问题,本文提出了一些具体的建议。 相似文献
8.
考虑赝势近似下囚禁于Paul阱中的单离子与双δ脉冲型周期势相互作用系统的规则与混沌运动.应用积分方程方法得到系统的经典运动精确解,通过数值方法作出相空间轨道图和平均能量的时间演化曲线.结合分析与数值结果,发现两个有趣的结论.即在离子与单δ脉冲作用出现共振失稳的情形,在双δ脉冲作用下却出现了稳定的规则运动;离子随着双δ脉冲中两个脉冲之间的时间间隔减小而由规则运动转为混沌运动,其平均能量扩散的快慢与混沌运动的混乱程度相关.还研究了系统的共振失稳,发现通过调节激光波矢可以控制这种不稳定性. 相似文献
9.
自由电子激光中的混沌现象及控制 总被引:1,自引:0,他引:1
本文评述了高技术项目之一自由电子激光(下文中简记为FEL)中的混沌问题。着重讨论了FEL中电子运动和光场发展的不稳定性与混沌现象,以及电子相空间运动轨道的混沌与光场混沌的控制、利用等。在讨论过程中,利用了混沌理论研究中的一些典型方法,如作Poincare截面,画电子的相空间运动轨道,计算Lia-punov指数,作功率谱等。从而揭示FEL中各种稳定、不稳定、及混沌等现象的内在规律性。最后,针对探索FEL的新概念、FEL技术的发展等问题,本文提出了一些具体的建议。 相似文献
10.
考虑赝势近似下囚禁于Paul阱中的单离子与双δ脉冲型周期势相互作用系统的规则与混沌运动.应用积分方程方法得到系统的经典运动精确解,通过数值方法作出相空间轨道图和平均能量的时间演化曲线.结合分析与数值结果,发现两个有趣的结论.即在离子与单δ脉冲作用出现共振失稳的情形,在双δ脉冲作用下却出现了稳定的规则运动;离子随着双δ脉冲中两个脉冲之间的时间间隔减小而由规则运动转为混沌运动,其平均能量扩散的快慢与混沌运动的混乱程度相关.还研究了系统的共振失稳,发现通过
关键词:
双δ脉冲
囚禁离子
精确解
混沌 相似文献
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Hessel Posthuma 《Letters in Mathematical Physics》2011,95(1):89-107
Using a coset version of the cubic Dirac operators for affine Lie algebras, we give an algebraic construction of the Dirac
induction homomorphism for loop group representations. With this, we prove a homogeneous generalization of the Weyl–Kac character
formula and show compatibility with Dirac induction for compact Lie groups. 相似文献
13.
A. Nazarov 《JETP Letters》2012,96(2):90-93
Schramm-Loewner evolution (SLE) and conformal field theory (CFT) are popular and widely used instruments to study critical behavior of two-dimensional models, but they use different objects. While SLE has natural connection with lattice models and is suitable for strict proofs, it lacks computational and predictive power of conformal field theory. To provide a way for the concurrent use of SLE and CFT, CFT correlation functions, which are martingales with respect to SLE, are considered. A relation between parameters of Schramm-Loewner evolution on coset space and algebraic data of coset conformal field theory is revealed. The consistency of this approach with the behavior of parafermionic and minimal models is tested. Coset models are connected with off-critical massive field theories and implications of SLE are discussed. 相似文献
14.
N. A. Batakis K. Farakos D. Kapetanakis G. Koutsoumbas G. Zoupanos 《Physics letters. [Part B]》1989,220(4):513-519
We consider the compactification of ten-dimensional Einstein-Yang-Mills theories over non-symmetric, six-dimensional homogeneous coset spaces with torsion. We examine the Einstein-Yang-Mills equations of motion requiring vanishing cosmological constant at ten and four dimensions and we present examples of compactictifying solutions. It appears that the introduction of more than one radii in the coset space, when possible, may be mandatory for the existence of compactifying solutions. 相似文献
15.
Samuel W. Macdowell 《Physics letters. [Part B]》1979,80(3):212-216
The methods of algebraic geometry are used to construct supergravity theories in a homogeneous superspace OSp(N|4) with structure group Sl(2C) ? ON and base supermanifold the coset space OSp(N|4)/(Sl(2C)? ON). The nature and origin of the supersymmetry transformations is completely elucidated. The equations of motion for O1 and O2 supergravity are obtained, as the realization of this symmetry on the space-time components hμ of the “supervierbein”. 相似文献
16.
The algebraic approach to the theory of collective motion is applied to the pairing interaction with two or three non-degenerate levels of arbitrary degeneracy each. A closed set of non-linear algebraic equations for observables referring to the lowest-lying levels of even nuclei is derived from the relevant quasispin algebra and from the equations of motion. Number conservation and blocking can both be taken into account. The solutions agree remarkably well with exact solutions even for small systems. 相似文献
17.
We give a direct Lie algebraic characterisation of conformal inclusions of chiral current algebras associated with compact, reductive Lie algebras. We use quantum field theoretic arguments and prove a longstanding conjecture of Schellekens and Warner on grounds of unitarity and positivity of energy. We explore the structures found to characterise conformal covariance subalgebras and coset current algebras. 相似文献
18.
Feng Xu 《Communications in Mathematical Physics》2000,211(1):1-43
All unitary Rational Conformal Field Theories (RCFT) are conjectured to be related to unitary coset Conformal Field Theories,
i.e., gauged Wess–Zumino–Witten (WZW) models with compact gauge groups. In this paper we use subfactor theory and ideas of
algebraic quantum field theory to approach coset Conformal Field Theories. Two conjectures are formulated and their consequences
are discussed. Some results are presented which prove the conjectures in special cases. In particular, one of the results
states that a class of representations of coset W
N
(N≥ 3) algebras with critical parameters are irreducible, and under the natural compositions (Connes' fusion), they generate
a finite dimensional fusion ring whose structure constants are completely determined, thus proving a long-standing conjecture
about the representations of these algebras.
Received: 5 November 1998 / Accepted: 18 October 1999 相似文献
19.
The highly excited vibrational levels of HCO in the electronic
ground state, \tilde {X}1A',are employed to determine the
coefficients of an algebraic Hamiltonian, by which the dynamical
potential is derived and shown to be very useful for interpreting
the intramolecular vibrational relaxation (IVR) which operates via
the HCO bending motion. The IVR inhibits the dissociation of H atom
and enhances the stochastic degree of dynamical character. This
approach is from a global viewpoint on a series of levels classified
by the polyad number which is a constant of motion in a certain
dynamical domain. In this way, the seemingly complicated level
structure shows very regular picture, dynamically. 相似文献
20.
We consider the dynamics invariant under the action of l-conformal Galilei group using the method of nonlinear realizations. We find that by an appropriate choice of the coset space parametrization one can achieve the complete decoupling of the equations of motion. The Lagrangian and Hamiltonian are constructed. The results are compared with those obtained by Galajinsky and Masterov (2013) [14]. 相似文献