Stabilization of the Soliton Transported Bio-energy in Protein Molecules in the Improved Model

We study the stabilization of the soliton transported bio-energy by the dynamic equations in the improved Davydov theory from four aspects containing the feature of free motion and states of the soliton at the long-time motion and at biological temperature 300 K and behaviors of collision of the solitons by Runge-Kutta method and physical parameter values appropriate to the $\alpha$-helix protein molecules. We prove that the new solitons can move without dispersion at a constant speed retaining its shape and energy in free and long-time motions and can go through each other without scattering. If considering further influence of the temperature effect of heat bath on the soliton, it is still thermally stable at biological temperature 300 K and in a time as long as 300 ps and amino acid spacings as large as 400, which shows that the lifetime of the new soliton is at least 300 ps, which is consistent with analytic result obtained by quantum perturbation theory. These results exhibit that the new soliton is a possible carrier of bio-energy transport and the improved model is possibly a candidate for the mechanism of this transport.     

Bio-energy in s-Helix Protein Molecules with Three Properties of Soliton-Transported Channels

We study numerically the propagating properties of soliton-transported bio-energy excited in the a-helix protein molecules with three channels in the cases of the short-time and long-time motions and its features of collision at temperature T = 0 and biological temperature T = 300 K by the dynamic equations in the improved Davydov theory and fourth-order Runge-Kutta method, respectively. From these simulation experiments we see that the new solitons in the improved model can move without dispersion at a constant speed retaining its shape and energy in the cases of motion of both short-time or T = 0 and long time or T = 300 K and can go through each other without scattering in their collisions. In these cases its lifetime is, at least, 120 ps at 300 K, in which the soliton can travel over about 700 amino acid residues. This result is consistent with analytic result obtained by quantum perturbed theory in this model. In the meanwhile, the influences of structure disorder of a-helix protein molecules, including the inhomogeneous distribution of amino acids with different masses and fluctuations of spring constant, dipole-dipole interaction, exciton-phonon coupling constant and diagonal disorder, on the solitons are also studied by the fourth-order Runge-Kutta method. The results show that the soliton still is very robust against the structure disorders and thermal perturbation of proteins at biological temperature 300 K. Therefore we can conclude that the new soliton in the a-helix protein molecules with three channels is a possible carrier of bio-energy transport and the improved model is possibly a candidate for the mechanism of this transport.     

Quantum Model of Energy Transport in Collagen Molecules

A semi-quantum model for energy transport in collagen molecules is presented.Soliton-like dynamics of this model is investigated numerically without and with the temperature efect taking into account.It is found that in both the cases energy can transport for a long distance along the collagen chain.This indicates that collagen molecules can be taken as a candidate for the acupuncture channel.     

Quantum Squeezing of Dark Solitons in Optical Fibers

The quantum theory of dark soliton propagation in fibers is studied based on the linearization approximation. Then the uncertainties in photon number, phase, position (time) and momentum of quantized dark solitons are calculated. Finally, the squeezing of the dark soliton is investigated by using homodyne detection and compared with bright soliton case.     

Quantum Solitons and Localized Modes in a One-Dimensional Lattice Chain with Nonlinear Substrate Potential

In the classical lattice theory, solitons and localized modes can exist in many one-dimensional nonlinear lattice chains, however, in the quantum lattice theory, whether quantum solitons and localized modes can exist or not in the one-dimensional lattice chains is an interesting problem. By using the number state method and the Hartree approximation combined with the method of multiple scales, we investigate quantum solitons and localized modes in a one-dimensional lattice chain with the nonlinear substrate potential. It is shown that quantum solitons do exist in this nonlinear lattice chain, and at the boundary of the phonon Brillouin zone, quantum solitons become quantum localized modes, phonons are pinned to the lattice of the vicinity at the central position j=j₀.     

Collisions of Two Soatial Solitons in Inhomogeneous Nonlinear Media

Collisions of spatial solitons occurring in the nonlinear Schroeinger equation with harmonic potential are studied, using conservation laws and the split-step Fourier method. We find an analytical solution for the separation distance between the spatial solitons in an inhomogeneous nonlinear medium when the light beam is self-trapped in the transverse dimension. In the self-focusing nonlinear media the spatial solitons can be transmitted stably, and the interaction between spatial solitons is enhanced due to the linear focusing effect （and also diminished for the linear defocusing effect）. In the self-defocusing nonlinear media, in the absence of self-trapping or in the presence of linear self-defocusing, no transmission of stable spatial solitons is possible. However, in such media the linear focusing effect can be exactly compensated, and the spatial solitons can propagate through.     

Effects of Spin Quantum Force in Magnetized Quantum Plasma

Starting from the governing equations for a quantum magnetoplasma including the electron spin -1/2 effects and quantum Bohm potential, we derive Korteweg-de Vries (KdV) equation of the system of quantum magnetohydrodynamics (QMHD). The amplitude and width of magnetosonic soliton with different parameters in the system are studied. It is found that the normalized Zeeman energy E plays a crucial role, for E≥1 the amplitude r_mξ and the width w_ξ of solitary wave all decrease as E increases. That is, the introduction of spin quantum force modifies the shape of solitary magnetosonic waves and makes them more narrower and shallower.     

Collisions of Two Spatial Solitons in Inhomogeneous Nonlinear Media

Collisions of spatial solitons occurring in the nonlinear Schröinger equation with harmonic potential are studied, using conservation laws and the split-step Fourier method. We find an analytical solution for the separation distance between the spatial solitons in an inhomogeneous nonlinear medium when the light beam is self-trapped in the transverse dimension. In the self-focusing nonlinear media the spatial solitons can be transmitted stably, and the interaction between spatial solitons is enhanced due to the linear focusing effect (and also diminished for the linear defocusing effect). In the self-defocusing nonlinear media, in the absence of self-trapping or in the presence of linear self-defocusing, no transmission of stable spatial solitons is possible. However, in such media the linear focusing effect can be exactly compensated, and the spatial solitons can propagate through.     

Influences of a Side-Coupled Triple Quantum Dot on Kondo Transport Through a Quantum Dot

Kondo transport properties through a Kondo-type quantum dot (QD) with a side-coupled triple-QD structure are systematically investigated by using the non-equilibrium Green's function method. We firstly derive the formulae of the current, the linear conductance, the transmission coefficient, and the local density of states. Then we carry out the analytical and numerical studies and some universal conductance properties are obtained. It is shown that the number of the conductance valleys is intrinsically determined by the side-coupled QDs and at most equal to the number of the QDs included in theside-coupled structure in the asymmetric limit. In the process of forming the conductance valleys, the side-coupled QD system plays the dominant role while the couplings between the Kondo-type QD and the side-coupled structure play the subsidiary and indispensable roles. To testify the validity of the universal conductance properties, another different kinds of side-coupled triple-QD structures are considered. It should be emphasized that these universal properties are applicable in understanding this kind of systems with arbitrary many-QD side structures.     

Superconductivity and Temperature Effects on Davydov Model of α-Helix Protein

We study the thermodynamic properties of α-helix protein on the basis of Davydov theory. The Hamiltonian of Davydov theory can be represented as a form of pairing Hamiltonian in the momentum space. We prove that the quasi-classical Davydov theory is essentially a theory with Bose condensation no matter whether the molecular excitations are treated as fermions or bosons. The transition temperature of superconductivity theory gives the existence condition of the Davydov soliton.     

线性聚焦和线性散焦效应对空间光孤子间相互作用的影响

考虑非均匀一维自聚焦介质的横向不均匀性,利用非线性薛定谔方程满足的守恒律给出了相邻空间孤子间隔的解析式,并对空间孤子之间的相互作用进行了数值模拟.结果表明,线形聚焦效应增强了空间孤子之间的相互作用;而线形散焦效应减弱了空间孤子之间的相互作用.当不考虑介质横向不均匀时,空间孤子之间发生周期性的碰撞.线性散焦效应使相邻空间孤子之间的间隔随传输距离发生周期性的变化,但孤子之间并不发生碰撞.线性聚焦效应使相邻空间孤子随传输距离发生周期性的碰撞,线性聚焦效应具有压制损耗使相邻空间孤子间隔变大的作用.     

The Features of Infrared Absorption of the Protein Molecules in the Living System

We utilize a vibron-soliton model for amide-I vibrational quanta interacting with optical phonons to study the feature of infrared absorption of the protein molecules with finite temperatuse.The self-trapping of amide-Ik vibrational quantum results in red shift of the main peak and largely anomalous band to occur in the infrared absorption for the protein molecules.utilizing the concise model of vibron and improved theory of color centers we have given theoretically the value of red shifts of the main peak and the intensity of anomalous band in infrared absorption,respectively,the latter reduces with increasing temperature which is consistent with the experimental result.     

Quantum Interference of Dual-Channel Excited Magnons in Spin-1 Bose-Einstein Condensates Atomic Chain

We investigate the quantum interference of spin wave excitations of a spin-1 atomic Bose condensate confined in an optical lattice. Single-channel and dual-channel interactions are employed in our system, and their induced excitations are compared. Also we consider the interplay of magneto-optical excitations, which leads to a constructive or destructive effect for the creation of magnons based on background excitations. The population distributions of excited magnons can be well controlled by steering the long-range dipole-dipole interactions. Such a scheme can be used to demonstrate conventional quantum-optical phenomena like dynamical Casimir effect at finite temperatures.     

Quantum Interference of Dual-Channel Excited Magnons in Spin-1 Bose-Einstein Condensates Atomic Chain

We investigate the quantum interference of spin wave excitations of a spin-1 atomic Bose condensate confined in an optical lattice. Single-channel and dual-channel interactions are employed in our system, and their induced excitations are compared. Also we consider the interplay of magneto-optical excitations, which leads to a constructive or destructive effect for the creation of magnons based on background excitations. The population distributions of excited magnons can be well controlled by steering the long-range dipole-dipole interactions. Such a scheme can be used to demonstrate conventional quantum-optical phenomena like dynamical Casimir effect at finite temperatures.     

Rashba效应对量子线中极化子激发态性质的影响

采用线性组合算符和幺正变换相结合的方法研究了Rashba效应对抛物量子线中强耦合束缚极化子激发态性质的影响,计算了束缚极化子的第一内部激发态能量、激发能量和振动频率。讨论了这些量对约束强度、自旋轨道耦合强度和库伦束缚势的依赖关系。数值计算结果表明:束缚极化子的第一内部激发态能量、激发能量和振动频率都随约束强度的增加而增大;但第一激发态能量随库仑束缚势和自旋与轨道之间耦合强度的增加而减少,而激发能量和振动频率随库仑束缚势的增加而增大。     

施加电场的半抛物量子阱中的电光效应

利用量子力学中的紧致密度矩阵方法，研究了施加电场的半抛物量子阱中的电光效应。通过位移谐振子变换，得到了系统中的电子态的精确解。对典型的GaAs材料进行数值计算的结果表明，随着电场强度的增加，电光效应系数几乎线性随之增加；但是随着半抛物量子阱受限势频率的增加，电光效应系数单调地减小；而且在同样的电场强度及抛物束缚势频率作用下，半抛物量子阱模型中的电光效应系数比抛物量子阱模型中的值大两个数量级，这是由于我们所选模型本身的非对称性以及电场进一步使这种非对称性增强的缘故。     

激发相干态下双模介观传输线的量子效应

将介观无损耗传输线中的驻波场看成作相对运动的两列同频率的行波的叠加，此电路量子化后成为两个频率相同、不同模的光子场。计算和分析了激发相干态下电压和电流梯度的量子涨落，指出了双模传输线与一般的LC电路、双模传输线与单模传输线量子涨落的异同之处。     

色散补偿光纤通信系统中孤子之间的相互作用

采用变分原理与位力定理研究了非线性光通信系统色散补偿方案中,相邻孤子之间的相互作用对孤子传输特性的影响。结果表明:在相位匹配与等幅孤子注入时,在普通单模光纤中这两个孤子先相互吸引,而后又相互排斥,显现周期性碰撞的变化规律,形成束缚孤子态,而在色散补偿光纤中传输的孤子之间不发生碰撞;对相位不匹配与等幅孤子注入,孤子之间发生分离;对相位匹配和不等幅孤子注入,在色散补偿光纤中传输的孤子,如果初始间隔φ0越小,应注入较大的初始幅值差η0,以利于孤子的传输。     

An Algebra of Effects in the Formalism of Quantum Mechanics on Phase Space

Defining an addition of the effects in the formalism of quantum mechanics on phase space, we obtain a new effect algebra that is strictly contained in the effect algebra of all effects. A new property of the phase space formalism comes to light, namely that the new effect algebra does not contain any pair of noncommuting projections. In fact, in this formalism, there are no nontrivial projections at all. We illustrate this with the spin-1/2 algebra and the momentum/position algebra. Next, we equip this algebra of effects with the sequential product and get an interpretation of why certain properties fail to hold. PACS: 02.10.Gd, 03.65.Bz. This paper was a submission to the Fifth International Quantum Structure Association Conference (QS5), which took place in Cesena, Italy, March 31–April 5, 2001.