一维介观结链中的双电荷孤子

采用半经典模型研究了一维介观结链中两个岛上各存在一个剩余电子时的电势分布,发现在一维介观链中存在双电荷孤子.双电荷孤子的主要特征是它的电势峰发生了劈裂,形成双峰,两峰在通常情况下不等高.研究了双电荷孤子电势峰和阈电压对一维介观结链结构参数的依赖关系.提出了研究双电荷孤子的等效单电荷孤子方法,表明在等效电荷区域,双电荷孤子的电势分布与等效单电荷孤子在同一区域的电势分布相同. 关键词： 双电荷孤子 介观结 单电子效应     

介观电路中电荷的量子效应

基于介观电路中电荷是量子化的基本事实，给出了介观电路的量子理论，并讨论了介观ＬＣ电路的量子涨落 关键词：     

电荷离散化时相干态下介观金属环中电荷与电流以及能量的量子涨落

基于电荷量子化的事实,运用最小平移算符Q∧的性质等,计算对应的相干态下介观金属环中电荷、电流及能量的量子涨落,研究影响量子涨落的因素.结果表明:计及电荷的离散性,在相干态下介观金属环中电荷、能量的量子涨落不为零,分别与电荷量子、相干态参量等因素有关;此外,能量的量子涨落还决定于金属环的电感、外磁通及其时间变化率的大小.     

压缩真空态下介观RLC电路中电荷和电流的量子涨落

发展了一种有源RLC电路的量子力学处理方案,在此基础上研究了压缩真空态下介观RLC电路中电荷和电流的量子涨落,着重研究了电阻和压缩参数对量子涨落的影响. 关键词：     

单离子各向异性影响下的一维铁磁链中的孤子

利用行波解法，研究了考虑交换各向异性和单离子各向异性的一维铁磁链，得出椭圆函数波解和孤子解,并讨论了单离子各向异性对椭圆函数波和孤子的影响.研究表明：单离子各向异性对一维铁磁链中椭圆函数波和孤子的激发及其稳定性有显著影响.单离子各向异性不利于易轴铁磁链中椭圆函数波和孤子解的激发，但有利于它们的稳定；而在易平面铁磁链中，单离子各向异性使椭圆函数波和孤子激发变得容易，但不利于它们的稳定.此外，还讨论了单离子各向异性对一维各向同性铁磁链中的孤子激发具有的影响. 关键词： 各向异性 单离子各向异性 孤子 铁磁链     

介观RLC电路中电荷和电流的量子涨落

发展了一种将有源RLC电路量子化的方法,在此基础上,研究了真空态下介观RLC电路中电荷、电流的量子涨落,特别是研究了电阻对量子涨落的影响.     

电荷不连续时电容耦合介观电路的量子回路方程及其能谱

考虑电荷具有不连续性的事实对双LC介观电路进行量子化,给出耦合形式的量子回路方程以及无相互作用Hamilton本征基矢下的电路能谱.结果表明,计及电荷离散性将使回路方程的形式发生明显变化;介观电路的能谱除与电路参数相关外,还明显地依赖于电荷的量子化性质.     

纳米隧道结的量子电容现象

利用STM针尖和二维Au纳米团簇构造的双隧道结，通过对单电子隧穿谱的测量，研究了纳米隧道结的电容随隧道结宽度的变化，发现电容随结宽度的变化偏离了经典电容的行为，为纳米隧道结的量子电容效应提供了实验证据。     

介观体系的物理

从对无序电子系统低温输运性质－弱局域电性的讨论出发，介绍了弹性散射和非弹发型用射的基本区别，引进了介观体系的概念，特别强调了与宏观体系不同之处，简单讲述了主要的物理发现，最后对本领域的现状做了简短的评述。     

无耗散介观电感耦合电路的库仑阻塞和电荷的量子效应

基于介观电路中电荷应是量子化的这一基本事实,给出了介观电感耦合电路的量子理论和库仑阻塞条件,并讨论了该介观电感耦合电路的量子涨落. 关键词： 介观电路 电感耦合 电荷的不连续性 库仑阻塞 量子涨落     

Optical soliton in a one-dimensional array of a metal nanoparticle-microcavity complex

Quantum coherence can be enhanced by placing metal nanoparticles (MNPs) in optical microcavities. Combining localized-surface plasmon resonances (LSPRs), nonlinear interaction between the LSPR and microcavity arrays of a MNP-microcavity complex offer a unique playground to observe novel optical phenomena and develop novel concepts for quantum manipulation. Here we theoretically demonstrate that optical solitons are achievable with a one-dimensional array which consists of a chain of periodically spaced identical MNP-microcavity complex systems. These differ from the solitons which stem from the MNPs with nonlinear Kerr-like response; the optical soliton here originates from LSPR-microcavity interaction. Using experimentally achievable parameters, we identify the conditions under which the nonlinearity induced by LSPR-microcavity interaction allows us to compensate for the dispersion caused by photon hopping of adjacent microcavities. More interestingly, the dynamics of solitons can be modulated by varying the radius of the MNP. The presented results illustrate the potential to utilize the MNP-microcavity complex for light manipulation, as well as to guide the design of photon switch and on-chip photon architecture.     

Resonances in the current-voltage characteristics of a dissipative Josephson junction

The I-V characteristics of a Josephson junction shunted by an Ohmic resistor shows sharp peaks when levels in neighbouring wells are crossing. We consider the shape and size of these peaks using a double-well model where the wells are given in parabolic approximation. The friction of arbitrary strength is included by the help of a bath of infinitely many degrees of freedom. 74.50.+z.     

Interaction of counterpropagating discrete solitons in a nonlinear one-dimensional waveguide array

We experimentally investigate the interaction of counterpropagating discrete solitons in a one-dimensional waveguide array in photorefractive lithium niobate. While for low input powers only weak interaction and formation of counterpropagating vector solitons are observed, for higher input powers a growing instability results in discrete lateral shifting of the formed discrete solitons. Numerical modeling shows the existence of three different regimes: stable propagation of vector solitons at low power, instability for intermediate power levels leading to discrete shifting of the two discrete solitons, and an irregular temporal dynamic behavior of the two beams for high input power.     

A comparison of barrier type tunnel junction and point contact tunnel junction formed on the same highT c material

By making a combination of both point contact and barrier type tunnel junctions on a single sample of the highT _c superconductor BSCCO (2212) single crystal, we have shown that as the tunneling tip is slowly retracted from the surface a point contact junction gradually evolves from a N-S short to a high resistance tunnel junction. The scaled dynamic conductance (dI/dV) of this point contact tunnel junction becomes almost identical to that of a conventional barrier type tunnel junction and both show a linear dI/dV —V curve. The observation implies that at high resistance a point contact junction behaves in the same way as a barrier type tunnel junction. We suggested that the almost linear tunneling conductance obtained in both the cases most likely arises due to an intrinsic characteristic of the surface of the crystal comprising of a mosaic of superconducting regions of the order of a few nanometers. We also conclude that the barrierless (N-S) point contact obtained by piercing the surface oxide layer of the crystal shows Andreev reflection which we suggest as the origin of the zero bias anomaly often observed in point contact junctions.     

Magnetoresistance in silicon based ferrite magnetic tunnel junction

We report magnetoresistance for silicon based magnetic tunnel junction. We used cobalt ferrite & cobalt nickel ferrite as free layer and pinned layer. The magnetoresistance measured at room temperature through silicon by fabricating FM/Si/FM magnetic tunnel junction. Magnetoresistance shows a loop type behavior with 3.7%. We have successfully demonstrated spin tunneling through silicon with ferrite junction that opens the door for potential candidate for spintronics devices. The spin-filtering effect for this double spin-filter junction is also discussed.     

超导隧道结中的电流相位关系

计算了等自旋配对超导隧道结中的直流Josephson电流.结果表明,当两侧超导体中配对势的轨道对称性分别属于磁点群D₄的A不可约表示和 ²E不可约表示的情况下,电流相位关系是I∝sin4φ. 关键词： 超导隧道结 Josephson电流     

Coherent multiple charge transfer in a superconducting NbN tunnel junction

We measured shot noise and submillimeter-wave response in a superconducting NbN tunnel junction that had a subharmonic gap structure on the current-voltage (I-V) curve. We found that the observed effective charge, defined from the noise-current ratio, tends to a steplike function of voltage. In the presence of submillimeter-wave radiation of frequency v, novel step structures spaced by hv/2e below and above the half-gap voltage clearly appeared on the I-V curve, overlapping the ordinary photon-assisted tunneling steps spaced by hv/e. Observation of these features provides clear evidence that coherent multiple Andreev reflection processes occur in the NbN tunnel junction with low barrier transparency.     

具有格点各向异性的一维铁磁链中的量子孤子和内禀局域模(英文)

基于Hartree-Fock方法和多标度方法,我们考察了具有格点各向异性的一维铁磁链中的量子孤子和内禀局域模,量子磁振子的波函数由量子包络孤子来描述.在布里渊区边界,量子包络孤子变成了量子内禀局域模,它的量子本征频率在简谐波带的顶部上方,量子磁振子主要集中在中心位置j=j0的附近.