Exact solution of a large class of interacting quantum systems exhibiting ground state singularities

We demonstrate how to construct a large class of interacting quantum systems for which an exact solution may be found for the ground state wave function and ground state energy for some range of interaction parameters. It is shown that the ground state exhibits singularities in these cases, and in some simple instances the exact ground state phase diagram and critical indices are also found.     

炸药爆轰产物Jones-Wilkins-Lee状态方程不确定参数

Jones-Wilkins-Lee (JWL)状态方程是一种不显含化学反应、由实验方法确定参数的半经验状态方程, 能比较精确地描述爆轰产物的膨胀驱动做功过程. 在JWL状态方程中有多个未知(不确定)参数需要确定. 传统的确定JWL状态方程参数的方法是“调参数”, 人为因素影响较大, 无法给出参数的不确定性信息. 本文利用贝叶斯分析方法研究了炸药的不确定参数, 该方法能够基于以往的认识、实验和模拟数据标定(calibration)不确定参数. 在本文结果中, 不确定参数的后验分布均值与文献结果相符合, 基于参数标定结果的数值模拟90%置信区间完全包含实验数据. 数值标定结果说明贝叶斯参数标定适用于确定样品炸药的JWL状态方程参数. 特别是, 在本文JWL状态方程参数标定过程中极大地减少了人为因素的影响.     

Controlling Decoherence from Fluctuating Magnetic Field

A different strategy is proposed to control decoherence from fluctuating magnetic field by adjusting external controllable parameters. The results show that the output states in terms of the fidelity are pure states, which correspond to the state vectors that are given by a renormalized Hamiltonian. Thus, the output states may perfectly preserve memory of initial single-qubit states at some critical magnetic field parameters.     

Bound states in many channel and single channel calculations

A distinction is made between bound states which can be calculated by a many channel method and those which can already be obtained parameter free by an inelastic single channel calculation. Two many channel models are investigated and it is shown that in some cases an inelastic single channel calculation needs additional parameters which are furnished by the many channel treatment only. The results may have some bearance on the problem whether the nucleon is a bound state.     

A simple feedback control for a chaotic oscillator with limited power supply

We proposed a simple feedback control method to suppress chaotic behavior in oscillators with limited power supply. The small-amplitude controlling signal is applied directly to the power supply system, so as to alter the characteristic curve of the driving motor. Numerical results are presented showing the method efficiency for a wide range of control parameters. Moreover, we have found that, for some parameters, this kind of control may introduce coexisting periodic attractors with complex basins of attraction and, therefore, serious problems with predictability of the final state the system will asymptote to.     

Temperature-dependence of phonons,solid state properties and liquid structure of noble metals: A comparison of pair-potentials

Two groups of effective pair-potentials are studied from the viewpoint of their suitability in being able to describe solid state properties and liquid state structure of noble metals Cu, Ag and Au over a wide temperature range. Since the effective pair-potentials are usually empirical in nature, with parameters obtained by fitting to some reference state properties, the objective of the present study is to determine whether a particular parametrization scheme has any definite advantage over another. We consider Morse potentials with parameters determined by equilibrium lattice parameter, cohesive/sublimation energies as well as bulk modulus values of the solid at low/room temperatures. The other group of potentials considered is Erkoç potentials, where the parameters were determined first by studying dimers and further modified using bulk stability condition and bulk cohesive energy values. The potentials were then used to study the energetics of microclusters containing 3–7 atoms. Quasiharmonic results for the solid obtained at different temperatures and Monte Carlo simulation for the liquid state show that phonon spectra, thermal expansion, temperature-dependence of specific heats and liquid structure are much better described by the latter group. The first group of potentials may have an advantage in reproducing the temperature-dependence of elastic constants and bulk moduli, since they are based on room temperature values of these properties, which show only weak temperature-dependence in general for all metals. It is argued that potentials based on parameters fitted to the properties at a single volume are less versatile in capturing the temperature-dependence of various thermodynamic properties over a wide range. Potentials capable of reproducing the energetics of clusters of different co-ordination numbers and volumes per atom may fare better in this regard.     

Operating a geometric quantum gate by external controllable parameters

A scheme to perfectly preserve an initial qubit state in geometric quantum computation is proposed for a single-qubit geometric quantum gate in a nuclear magnetic resonance system. At first, by adjusting some magnetic field parameters, one can let the dynamic phase be proportional to the geometric phase. Then, by controlling the azimuthal angle in the initial state, we may realize a geometric quantum gate whose fidelity is equal to one under cyclic evolution. This means that the quantum information is no distortion in the process of geometric quantum computation.     

在非线性J—C模型系统中制备“薛定谔猫态”

证明在含有克尔介质的双光子Ｊ－Ｃ模型系统中通过对原子的测量可以制备“薛定谔猫态”。选择适当的测量时间，原子初态及非线性系数，即可产生偶相干态，奇相干态和Ｙ－Ｓ相干态。     

Performance of a quantum key distribution protocol with dual-rail displaced photon states

We propose a scheme for a quantum key distribution (QKD) protocol with dual-rail displaced photon states. Displaced single-photon states with different amplitudes carry bit values of code that may be extracted, while coherent states carry nothing and only provide an inconclusive outcome. A real resource of single photons is used, involving imperfections associated with experimental technique that result in a photon state with an admixture of the vacuum state. The protocol is robust against the loss of a single photon and the inefficiency of the detectors. Pulses with large amplitudes, unlike the conventional QKD relying on faint laser pulses, are used that may approximate it to standard telecommunication and may show resistance to eaves-dropping even in settings with high attenuation. Information leakage to the eavesdropper is determined from comparison of the output distributions of the outcomes with ideal ones that are defined by two additional parameters accessible to only those send the pulses. Robustness to some possible eavesdropping attacks is shown.     

与二项式光场相互作用的运动原子熵压缩

运用量子信息熵理论,研究了二项式光场与运动二能级原子相互作用过程中运动原子的信息熵压缩。讨论了不同的原子初态和场的有关参数对原子信息熵压缩的影响。结果表明：选择原子初态、场模结构、场调节参数及原子运动速度可以调控原子信息熵的压缩方向、偶极矩分量值和压缩周期;适当的选择参数可得到持续性的原子信息熵压缩。     

Decoherence of spin-deformed bosonic model

The decoherence rate and some parameters affecting it are investigated for the generalized spin-boson model. We consider the spin-bosonic model when the bosonic environment is modeled by the deformed harmonic oscillators. We show that the state of the environment approaches a non-linear coherent state. Then, we obtain the decoherence rate of a two-level system which is in contact with a deformed bosonic environment which is either in thermal equilibrium or in the ground state. By using some recent realization of f$f$-deformed oscillators, we show that some physical parameters strongly affect the decoherence rate of a two-level system.     

Spontaneous switching in cavityless optically bistable systems

Relaxation cavityless optical bistability is studied when a semiconductor is exposed to light quanta with an energy exceeding the transition energy and the free-electron relaxation time depends on temperature. The numerical analysis of dynamic equations for temperature and free-electron density demonstrates that 11 regimes of light-semiconductor interaction are possible. The regimes are classified in terms of the features of temperature-intensity characteristic curves, namely, by the number and arrangement of instability and quasistability segments and by the presence or absence of bistability. It is found that both the upper and the lower branch of a bistable characteristic curve may be unstable, which results in spontaneous switchings between the respective states. Similarly, if the upper state is unstable and the lower state is stable, a small perturbation of the parameters (free-electron temperature and density) near the former causes the transition to the oscillatory regime. If the upper state is unstable and a small perturbation of the lower (stable) state excites a damped oscillation, spontaneous switchings result if the fluctuating temperature exceeds some critical value for the lower state.     

Formation of large‐scale structures in four‐component dusty plasmas

A possibility of self‐organization of magnetized four‐component dusty plasmas to double Beltrami (DB) state is explored. It is found that for a specific set of Beltrami parameters, the four‐component dusty plasma self‐organizes to DB state. The DB state characterized by two scale parameters may represent a paramagnetic or diamagnetic field structure. The impact of Beltrami parameters, charge and densities of dust grains on formation of self‐organized structures has also been investigated. This study has potential relevance to the formation of large‐scale structures in astrophysical plasmas.     

Some studies of the interaction between two two-level atoms and SU(1,1) quantum systems

Herein, we present an approach to look for the best phenomenon to measure quantum correlation. The system of two isolated qubits each interacting with a single-mode cavity was theoretically created to study the quantum correlation. Some of the phenomena, such as the quantum discord and concurrence, were generated through such a system. The influences of initial state purity, qubit motion, and detuning parameters were discussed for the phenomena. These parameters for a specific value show that the behavior of phenomena are analogous. It is interesting to mention that some values of detuning undergo a sudden death of phenomena, and the quantum discord still captures the qubits quantum correlation. We predict that the quantum discord may be a better measure of quantum correlation than concurrence.     

分子聚集理论在医药学研究中的应用

本文利用聚集型状态方程，克拉贝龙方程以及临界条件推出聚集活性参量方程．分析结果表明，医药的药理活性是可以用聚集活性参量予以定量表征．本文给出了某些医药的主要的药物成分，如氧化亚氮 乙醚、氯仿和水杨酸甲酯等嘛醉剂），一氧化氮（硝酸甘油）、乙醇胺（医药活性剂）和多巴胺（神经递质）的生物活性数据．实践经验表明，这些化学品分别在生命体的心血管系统、神经系统和免疫系统中起着重要的药理功能作用．这表明，本文研究的内容在医药学研究领域有其重要意义．     

Spin Squeezing in Superposition of Four-Qubit Symmetric State and W States

We investigate the entanglement property of a four-qubit state superposed by a four-qubit GHZ state and a symmetric state with spin squeezing. Numerically and analytic solutions for spin squeezing parameters are given. The squeezed parameters depend on the superpose coefficients and the relative phases. It is shown that there is no spin squeezing at n ₁ direction and it occurs at n ₂ direction under some conditions.     

Accretion onto Charged Black Holes in Einstein and Massive Theories of Gravity *

The accretion process is being investigated onto some important black holes such as Born-Infeld-AdS black hole, non-linear charged black hole solution in AdS space-time and Einstein-Yang-Mills massive gravity in the presence of Born-Infeld nonlinear electrodynamics. We find out the relations of radial velocity, energy density and change of mass for mention black holes and analyze their behavior graphically for different values of equation of state parameters $\omega$. We also examine the relations for critical speed for these black holes. It is observed that for different state parameters different fluids exhibit different evolutions in black holes backgrounds. The energy density of some fluids is negative or positive near the black hole while other fluids become cause to increase or decrease in black hole mass.     

State estimation for neural neutral-type networks with mixed time-varying delays and Markovian jumping parameters

This paper is concerned with a delay-dependent state estimator for neutral-type neural networks with mixed timevarying delays and Markovian jumping parameters.The addressed neural networks have a finite number of modes,and the modes may jump from one to another according to a Markov process.By construction of a suitable Lyapunov-Krasovskii functional,a delay-dependent condition is developed to estimate the neuron states through available output measurements such that the estimation error system is globally asymptotically stable in a mean square.The criterion is formulated in terms of a set of linear matrix inequalities(LMIs),which can be checked efficiently by use of some standard numerical packages.     

弱测量对四个量子比特量子态的保护

廖湘萍等(Chin.Phys.B 23 020304,2014)指出弱测量和弱测量反转操作可以保护三个量子比特的纠缠,提高保真度.本文将弱测量方法推广至四个量子比特的情况,研究了几种典型四个量子比特量子态的演化.结果表明:在振幅阻尼通道中,弱测量方法能够有效地提高系统量子态的保真度.分析了影响量子态保真度的各种因素,对比了不同量子态的演化特征,划分了量子态保真度提高的敏感区域.最后,对弱测量方法抑制量子态衰减的内在机制做了合理的物理解释.     

The ratio of normal state to superconducting state of spin lattice relaxation rate of unconventional superconductors

In this research, we derive a simple expression for the ratio of normal state superconducting state of spin lattice relaxation rate of unconventional superconductors from the BCS weak-coupling equation. The unconventional superconductors we consider have three types of order parameters as d-wave, ³He A-phase and p-wave three-dimensional order parameter that had been done before by Parker and Haas [D. Parker, S. Haas, Physical Review B 75 (2007) 052501]. After using some numerical approximations and some boundary conditions, we can find the ratio of normal state to superconducting state of spin lattice relaxation rate in power series of temperature dependent order parameters and temperature. Our numerical calculations show the coherence peak below critical temperature clearly that are consistent with Parker and Haas [D. Parker, S. Haas, Physical Review B 75 (2007) 052501]. These results do not agree with the believed that the coherence peak is the only property of s-wave superconductor. However from our calculation, we can conclude that the unconventional superconductors can show the coherence peaks.