A no-go result for the quantum damped harmonic oscillator

In this letter we show that it is not possible to set up a canonical quantization for the damped harmonic oscillator using the Bateman Lagrangian. In particular, we prove that no square integrable vacuum exists for the natural ladder operators of the system, and that the only vacua can be found as distributions. This implies that the procedure proposed by some authors is only formally correct, and requires a much deeper analysis to be made rigorous.     

用自洽平均值法计算非线性谐振子本征值

提出了一种自洽平均值法计算非线性谐振子本征值的方法.研究结果表明,等效势能曲线、坐标算符的一次项和二次项的平均值及能量本征值均在主量子数n较小时与微扰量子理论相吻合,在n=0时两者完全一致.     

Quantum phases for a generalized harmonic oscillator

An effective Hamiltonian for the generalized harmonic oscillator is determined by using squeezed state wavefunctions. The equations of motion over an extended phase space are determined and then solved perturbatively for a specific choice of the oscillator parameters. These results are used to calculate the dynamic and geometric phases for the generalized oscillator with this choice of parameters.      

Thermal state of the general time-dependent harmonic oscillator

Taking advantage of dynamical invariant operator, we derived quantum mechanical solution of general time-dependent harmonic oscillator. The uncertainty relation of the system is always larger than ħ/2 not only in number but also in the thermal state as expected. We used the diagonal elements of density operator satisfying Leouville-von Neumann equation to calculate various expectation values in the thermal state. We applied our theory to a special case which is the forced Caldirola-Kanai oscillator.     

Wave function of the harmonic oscillator in classical statistical mechanics

The notion of wave function of the classical harmonic oscillator is discussed. The evolution equation for this wave function is obtained using the classical Liouville equation for the probability-distribution function of the harmonic oscillator. The tomographic-probability distribution of the classical oscillator is studied. Examples of the ground-like state and the coherent state of the classical harmonic oscillator are considered.     

谐振子径向幂坐标矩阵元的一般递推关系

利用谐振子径向波函数的渐近行为和积分特性,导出了谐振子径向幂坐标矩阵元〈n′_rl′|r~k|n_rl〉的递推关系,从而把有关文献中关于对角元〈n_rl|r~k|n_rl〉的递推关系推广到更为一般的形式。     

用不变量方法求含时谐振子的波函数

利用辅助方程从含量谐振子的哈密量出发得到了两个不变量，利用这两个不变量求得了系统薛定谔方程的解。     

Coherent states of general time-dependent harmonic oscillator

By introducing an invariant operator, we obtain exact wave functions for a general time-dependent quadratic harmonic oscillator. The coherent states, both inx- andp-spaces, are calculated. We confirm that the uncertainty product in coherent state is always larger thankh/2 and is equal to the minimum of the uncertainty product of the number states. The displaced wave packet for Caldirola-Kanai oscillator in coherent state oscillates back and forth with time about the center as for a classical oscillator. The amplitude of oscillation with no driving force decreases due to the dissipation in the system. However, the oscillation with resonant frequency oscillates with a large amplitude, even after a sufficient time elapse.     

受与速度平方成正比的力的变频率谐振子

受与速度平方成正比的力的变频率谐振子(THOFQV)可以用一个适当的Lagrangian量来描述，可以求出THOFQV的普遍解.再利用不变量算子求解该系统的Schrdinger方程，得到本征函数和本征值. 关键词： 谐振子 不变量 本征函数 本征值     

Exact solution to two-dimensional isotropic charged harmonic oscillator in uniform magnetic field in non-commutative phase space

In this paper, the isotropic charged harmonic oscillator in uniform magnetic field is researched in the non-commutative phase space; the corresponding exact energy is obtained, and the analytic eigenfunction is presented in terms of the confluent hypergeometric function. It is shown that in the non-commutative space,the isotropic charged harmonic oscillator in uniform magnetic field has the similar behaviors to the Landau problem.     

阻尼谐振子的拉格朗日函数和哈密顿函数

利用一种直接方法将阻尼谐振动微分方程变换成等价的自伴随形式,并构造出阻尼振子的两个拉格朗日函数和哈密顿函数,导出了阻尼谐振子的Noether守恒量.     

过阻尼谐振子的随机共振

研究了由交叉相关高斯白噪声驱动的过阻尼谐振子的随机共振,其中加法噪声被周期信号所调制,运用平稳关联函数的傅里叶变换,导出了过阻尼谐振子随机模型信噪比的精确表达式.结果揭示:在过阻尼谐振子的随机模型中存在二类随机共振.一类随机共振表现为信噪比随乘法噪声强度Q变化的曲线存在共振峰,另一类随机共振表现为信噪比随振子频率ω变化的曲线存在共振峰.大幅度改变信号频率Ω值的大小,信噪比随乘法噪声强度Q变化的曲线有单峰,一峰一谷和单调变化三种不同的形式.     

谐振子基在复标度方法中的应用

在利用薛定谔方程求解共振态能量的过程中,成功的将谐振子基应用于复标度方法,求解出共振态的能量公式,并以一个比较成熟的势作为检验势,得出比较精确的结果,也作出共振态能量在复能量坐标系中的能量分布.对其中的两个参数基数N和转动角θ进行讨论与分析,验证了共振态的一个原理:在对共振态的计算过程中,计算参数的改变不会影响共振态的位置.     

耦合谐振子的双波描述

采用双波函数量子理论 ,研究了耦合谐振子力学量的时间演化方程及其经典极限 ,进一步验证了双波函数描述的是单个粒子 ,而单个波函数描述的是量子系综的结论     

Quantum harmonic oscillator presented in a nonorthodox approach

An example of nonequivalent but s-equivalent Lagrange function for a one-dimensional harmonic oscillator are presented and discussed. The quantum approach displays a quite different structure from the usual standard one.     

量子阻尼振子的两种解析解法

应用u变换与不变量理论，求解一维量子阻尼振子，两种解法的不同仅在于交换了u变换与相因子的顺序。     

三维各向同性谐振子的径向基本算符

采用新的方法,推导出三维各向同性谐振子径向基本算符r,r,1r对本征函数的作用结果,由此得出其升降算符及其他新的公式,并证明文献[1]中的结论有误 关键词： 基本算符 升降算符 三维谐振子     

用拉普拉斯变换得到N维谐振子的精确解

通过拉普拉斯变换可以把N维谐振子的Schr?dinger方程退化为一次微分方程，然后得到精确的束缚态解。结果显示这种求解Schr?dinger方程方法跟低维一样可以代替标准的函数分析方法。     

谐振子基在复标度方法中的应用

在利用薛定谔方程求解共振态能量的过程中,成功的将谐振子基应用于复标度方法,求解出共振态的能量公式,并以一个比较成熟的势作为检验势,得出比较精确的结果,也作出共振态能量在复能量坐标系中的能量分布。对其中的两个参数基数N和转动角µ进行讨论与分析,验证了共振态的一个原理：在对共振态的计算过程中,计算参数的改变不会影响共振态的位置。