Momentum of Φ Field and Inflation

With quantum mechanical method, we discuss the metastable states of the quantum universe, and give two eigenstates corresponding to nonzero and zero conjugate momenta P_Φ under the assumption of p=-5, where p is the ordering factor. Analyaea for their classical evolution are made, and there comes a conclusion: The mom-entum of the scalar field of quantum state has very little effect on its later classical evolution. This gives a favourable support to the classical theory of inflation.     

Quantum anomalous hall effect in Hg1-yMnyTe quantum wells

The quantum Hall effect is usually observed when a two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{1-y}Mn{y}Te quantum wells, without an external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.     

Investigation of Dynamical Parameters of Exciton Confined in CdS Spherical Quantum Dots with a B-Spline Technique

Exciton energies as a function of radii of quantum dots in the range of 5-35 A are calculated based on effective mass approximation model with the B-spline technique and compared with experimental and other theoretical data for the CdS dots. This method leads to accurate and fast convergent exciton energy, which are in good agreement with experimental data in the whole confinement regime. The effect of penetration of wave function from the inside to the outside of the dots and the effect of dielectric constants are taken into account. The magnitudes of dynamical parameters are discussed. It is found that the different materials surrounding the CdS quantum dot affect not only the potential energy and Coulomb interaction energy of the system, but also the effective masses. The comparison shows that the effective mass approximation model can describe very well the quantum size effects observed experimentally on the exciton ground state energy.     

Laser-induced quantum coherence in a semiconductor quantum well

The phenomenon of electromagnetically induced quantum coherence is demonstrated between three confined electron subband levels in a quantum well which are almost equally spaced in energy. Applying a strong coupling field, two-photon resonant with the 1-3 intersubband transition, produces a pronounced narrow transparency feature in the 1-2 absorption line. This result can be understood in terms of all three states being simultaneously driven into "phase-locked" quantum coherence by a single coupling field. We describe the effect theoretically with a density matrix method and an adapted linear response theory.     

若丹明6G溶液体系的荧光量子效率

本文对八种若丹明6G溶液的荧光量子效率进行了测量,并着重讨论了染料若丹明6G溶液体系的量子效率的溶剂效应.在研究中发现:若丹明6G溶渡的荧光量子效率与溶液极性(ε-1)/(2ε+1)之间存在线性关系,体系的荧光量子效率随溶剂极性的增加而下降.由于染料分子与成氢键溶剂作用愈强,能量散逸愈快将是导致这一结果的主要原因.这一规律也适用于ANS染料溶液体系中.     

湍流大气对量子密钥分布系统性能的影响

自由空间量子密钥分布系统是全球性量子保密通信的关键组成部分之一。因此研究湍流大气信道对量子密钥分布系统性能的影响就非常重要。使用光束近场传播和统计分析的方法定量分析了湍流大气信道对基于BB84协议的自由空间量子密钥分布系统的误码率的影响。数值计算结果表明,大气衰减系数超过-3dB/km时,大气衰减对量子密钥分布系统的误码率影响很大;在大气传输因子小于0.5的区域,系统误码率比无湍流影响时的系统误码率高出一个数量级。     

Blockade of tunneling in a suspended single-electron transistor

The tunneling of electrons that is limited by the Coulomb blockade effect in a single-electron transistor with a quantum dot based on a narrow GaAs/AlGaAs quantum wire suspended over a substrate is investigated. By means of a direct comparison experiment, the tunneling features associated with the separation of the quantum dot from the substrate are revealed. In addition to an increase in the charge energy (Coulomb gap), which reaches 170 K in temperature units, the dependence of this energy on the number of electrons in the quantum dot, which varies from zero to four, is observed. This dependence is explained by a change in the effective size of the dot due to the effect of the depleting gate voltage. Moreover, the additional blockade of tunneling that is different from the Coulomb blockade and is specific for suspended structures is observed. It is shown that this blockade is not associated with the dynamical effect of exciting local phonon modes and can be attributed to the change in the static elastic strains in the quantum wire that accompany the tunneling of an electron to/from the quantum dot.     

Raman磁共振谱中强单量子信号的压抑

通常单量子信号的强度在Raman磁共振谱中要比其它多量子信号的强度大得多,因而易引起接收机饱和,使信号发生变形,不利于多量子信号的检测,因此压抑强的单量子峰是必要的.积算符理论分析表明,异核体系Raman磁共振谱的单,多量子峰的共振频率及其信号强度关于频偏满足对称关系:当频偏由正变为负时,单量子信号的强度亦随之改变了符号.因此,对正负频偏(数值相等)的两次Raman磁共振实验的FID信号进行累加,就可压抑强的单量子峰,而对于多量子峰则在大的频偏条件下不会相互抵消.因此,这样的实验累加可以保持多量子信号的强度而压抑掉强的单量子峰.作为实验验证,我们给出了异核AX_n体系(CHCl₃,CH₂Cl₂,CH₃OH)的按上述正负频偏循环累加采样方法得到Raman磁共振¹³C实验谱.实验结果同理论预言完全一致.     

Modular variables in quantum theory

The non-local aspects of interaction between quantum systems are investigated. These aspects are particularly conspicuous in quantum phenomena without a classical analog, such as the quantum effects of electromagnetic potentials. The study of the potential effect leads to the introduction of a new type of dynamical variable, the modular variable, which brings out the physical features of quantum mechanical non-locality.The material contained in this article is based on work done in the period 1965–67. This work was supported in part by O.A.R. Air Force Cambridge Research Laboratories, Bedford, Mass., U.S.A., under Contracts No. AF 19(629)-5143 and AF 19(628)-5833.     

Gravity-induced geometric spin Hall effect of freely falling quantum particle

We discuss a new gravitational effect that the wave packet of a free-fall quantum particle undergoes a spin-dependent transverse shift in Earth's gravitational field. This effect is similar to the geometric spin Hall effect (GSHE) (Aiello 2009 et al Phys. Rev. Lett. 103 100401 ), and can be called gravity-induced GSHE. This effect suggests that the free-fall wave packets of opposite spin-polarized quantum particles can be split in the direction perpendicular to spin and gravity.     

Atomic Scale of an Electrical Area for Unipolar Light Pulses

JETP Letters - A new parameter of “the atomic scale of an electrical area” has been introduced. It shows the effect of unipolar pulses on a quantum system. This parameter is equal to...     

Organic quantum well and superlattice characteristics in quasi-one-dimensional multiblock copolymers

A tight-binding calculation was presented to describe multiblock copolymers, such as [...-(PA)x-(PPP)y-...] composed of PA (polyacetylene) and PPP (poly(p-phenylene). It is found that a copolymer has a quantum well and superlattice characteristics, and evident is the effect of the composite lengths, the interfacial couplings and the electron-phonon interactions on the electronic properties of a copolymer. The quantum tunneling, the Franz-Keldysh effect and the quantum confinement can be generated under an applied electric field. These results were compared to those of traditional inorganic quantum well and superlattice systems.     

Multiple coherence resonances by time-periodic coupling strength in scale-free networks of bursting neurons

We investigate the algebraic structure of flat energy bands a partial filling of which may give rise to a fractional quantum anomalous Hall effect (or a fractional Chern insulator) and a fractional quantum spin Hall effect. Both effects arise in the case of a sufficiently flat energy band as well as a roughly flat and homogeneous Berry curvature, such that the global Chern number, which is a topological invariant, may be associated with a local non-commutative geometry. This geometry is similar to the more familiar situation of the fractional quantum Hall effect in two-dimensional electron systems in a strong magnetic field.     

量子点浮置栅量子线沟道三栅结构单电子场效应管存储特性的数值模拟

通过建立二维薛定谔方程和泊松方程数值模型,对基于硅量子点浮置栅和硅量子线沟道三栅结构单电子场效应管(FET)存储特性进行了研究.通过在不同尺寸、栅压和不同写入电荷条件下,对硅量子线沟道中电子浓度的二维有限元自洽数值求解,研究了在纳米尺度下硅量子线沟道中量子限制效应和电荷分布对于器件特性的影响.模拟结果发现,沟道的导通阈值电压随着尺寸的缩小而提高,并随浮置栅内存储的电子数目的增加而明显升高.然而,这样的增加趋势在受到纳米尺度沟道中高电荷密度的影响下将出现非线性饱和趋势.进一步研究发现,当沟道尺寸较小时,沟道 关键词： 三栅单电子FET存储器 量子效应 薛定谔方程 泊松方程     

Influence of superpositional wave function oscillations on Shor's quantum algorithm

We investigate the influence of superpositional wave function oscillations on the performance of Shor's quantum algorithm for factorization of integers. It is shown that wave function oscillations can modify the required quantum interference. This undesirable effect can be routinely eliminated using a resonant pulse implementation of quantum computation, but requires special analysis for nonresonant implementations. We also discuss the influence of this effect on implementation of other quantum algorithms.     

Propagation of Surface Modes in a Warm Non-Magnetized Quantum Plasma System

The propagation of surface modes in warm non-magnetized quantum plasma is investigated.The surface modes are assumed to propagate on the plane between vacuum and warm quantum plasma.The quantum hydrodynamic model including quantum diffraction effect(the Bohm potential) and quantum statistical pressure is used to derive a new dispersion relation of surface modes.The new dispersion relation of surface modes is analyzed in some special interesting cases.It is shown that the dispersion relation can be reduced to the earlier results in some special cases.The results indicate that the quantum effects can facilitate the propagation of surface modes in such a semi-bounded plasma system.This work is helpful to understand the physical characteristics of the surface modes and the bounded quantum plasma.     

The stability of the fractional quantum Hall effect in topological insulators

With the recent observation of graphene-like Landau levels at the surface of topological insulators, the possibility of fractional quantum Hall effect, which is a fundamental signature of strong correlations, has become of interest. Some experiments have reported intra-Landau level structure that is suggestive of fractional quantum Hall effect. This paper discusses the feasibility of fractional quantum Hall effect from a theoretical perspective, and argues that while this effect should occur, ideally, in the n=0 and |n|=1 Landau levels, it is ruled out in higher |n| Landau levels. Unlike graphene, the fractional quantum Hall effect in topological insulators is predicted to show an interesting asymmetry between n=1 and n=−1 Landau levels due to spin-orbit coupling.     

Controlling of entropic uncertainty in open quantum system via proper placement of quantum register

We investigate the dynamical behaviors of quantum-memory-assisted entropic uncertainty and its lower bound in the amplitude-damping channel. The influences of different placement positions of the quantum register on the dynamics of quantum coherence, quantum entanglement, and quantum discord are analyzed in detail. The numerical simulation results show that the quantum register should be placed in the channel of the non-Markovian effect. This option is beneficial to reduce the entropic uncertainty and its lower bound. We also find that this choice does not change the evolution of the quantum coherence and quantum entanglement, but changes the dynamical process of the quantum discord of the system.These results show that quantum coherence, quantum entanglement, and quantum discord are different quantum resources with unique characteristics and properties, and quantum discord can play a key role in reducing the uncertainty of quantum systems.     

Quantum simulations of classical annealing processes

We describe a quantum algorithm that solves combinatorial optimization problems by quantum simulation of a classical simulated annealing process. Our algorithm exploits quantum walks and the quantum Zeno effect induced by evolution randomization. It requires order 1/sqrt delta steps to find an optimal solution with bounded error probability, where delta is the minimum spectral gap of the stochastic matrices used in the classical annealing process. This is a quadratic improvement over the order 1/delta steps required by the latter.     

Observation of Electron Spin Resonance in the Microwave-Induced Photovoltage

JETP Letters - The microwave-induced photovoltage in two-dimensional electron systems in an AlAs quantum well and a ZnO/MgZnO heterojunction under the conditions of the quantum Hall effect is...