Improved statistical fluctuation analysis for two decoy-states phase-matching quantum key distribution

Phase-matching quantum key distribution is a promising scheme for remote quantum key distribution,breaking through the traditional linear key-rate bound.In practical applications,finite data size can cause significant system performance to deteriorate when data size is below 1010.In this work,an improved statistical fluctuation analysis method is applied for the first time to two decoy-states phase-matching quantum key distribution,offering a new insight and potential solutions for improving the key generation rate and the maximum transmission distance while maintaining security.Moreover,we also compare the influence of the proposed improved statistical fluctuation analysis method on system performance with those of the Gaussian approximation and Chernoff-Hoeffding boundary methods on system performance.The simulation results show that the proposed scheme significantly improves the key generation rate and maximum transmission distance in comparison with the Chernoff-Hoeffding approach,and approach the results obtained when the Gaussian approximation is employed.At the same time,the proposed scheme retains the same security level as the Chernoff-Hoeffding method,and is even more secure than the Gaussian approximation.

Topological edge and corner states of valley photonic crystals with zipper-like boundary conditions

We present a stable valley photonic crystal(VPC)unit cell with C_(3v)symmetric quasi-ring-shaped dielectric columns and realize its topological phase transition by breaking mirror symmetry.Based on this unit cell structure,topological edge states(TESs)and topological corner states(TCSs)are realized.We obtain a new type of wave transmission mode based on photonic crystal zipper-like boundaries and apply it to a beam splitter assembled from rectangular photonic crystals(PCs).The constructed beam splitter structure is compact and possesses frequency separation functions.In addition,we construct a box-shaped triangular PC structures with zipper-like boundaries and discover phenomena of TCSs in the corners,comparing its corner states with those formed by other boundaries.Based on this,we explore the regularities of the electric field patterns of TESs and TCSs,explain the connection between the characteristic frequencies and locality of TCSs,which helps better control photons and ensures low power consumption of the system.

Pixelated non-volatile programmable photonic integrated circuits with 20-level intermediate states

Multi-level programmable photonic integrated circuits(PICs)and optical metasurfaces have gained widespread attention in many fields,such as neuromorphic photonics,opticalcommunications,and quantum information.In this paper,we propose pixelated programmable Si_(3)N_(4)PICs with record-high 20-level intermediate states at 785 nm wavelength.Such flexibility in phase or amplitude modulation is achieved by a programmable Sb_(2)S_(3)matrix,the footprint of whose elements can be as small as 1.2μm,limited only by the optical diffraction limit of anin-house developed pulsed laser writing system.We believe our work lays the foundation for laser-writing ultra-high-level(20 levels and even more)programmable photonic systems and metasurfaces based on phase change materials,which could catalyze diverse applications such as programmable neuromorphic photonics,biosensing,optical computing,photonic quantum computing,and reconfigurable metasurfaces.

Control Factors and Diversities of Phase State of Oil and Gas Pools in the Kuqa Petroleum System

Based on the analysis of the hydrocarbon geochemical characteristics in the Kuqa petroleum system of the Tarim Basin, this study discusses the causes and controlling factors of the phase diversities and their differences in geochemical features. According to the characteristics and differences in oil and gas phase, the petroleum system can be divided into five categories： oil reservoir, wet gas reservoir, condensate gas-rich reservoir, condensate gas-poor reservoir and dry gas reservoir. The causes for the diversities in oil and gas phases include diversities of the sources of parent material, maturity of natural gas and the process of hydrocarbon accumulation of different hydrocarbon phases. On the whole, the Jurassic and Triassic terrestrial source rocks are the main sources for the hydrocarbon in the Kuqa Depression. The small differences in parent material may cause diversities in oil and gas amount, but the impact is small. The differences in oil and gas phase are mainly affected by maturity and the accumulation process, which closely relates with each other. Oil and gas at different thermal evolution stage can be captured in different accumulation process.

PREDICTION OF THE PHASE BEHAVIOR OF GAS CONDENSATES USING PATEL-TEJA EQUATION OF STATE AND GAMMA DISTRIBUTION FUNCTION

The three-parameter Petal-Teja equation of state coupled with a characterization proceduref0r C7+-fraction based on gamma distribution function was employed to predict the phase behaviorof eight gas condensates.The lumping of the subdivided single carbon number（SCN）hydrocarbons inthe plus-fraction and the choice of empirical correlations for calculating the critical properties andacentric factor of SCN hydrocarbons were discussed.

The Wigner function and phase properties of superposition of two coherent states with the vacuum state

This paper discusses some statistical properties of the superposition of two coherent states with a vacuum state, such as sub-Poissonian photon statistics and negativity of the Wigner function. Phase probability distribution and phase variance are calculated. Special cases of the constructed superposition states are presented. The results show that depending on the vacuum state coefficient γ and the coherent state coefficient a, it can generate a variety of nonclassical states.

A Study on Phase States of the Catalytic System of FeCl_3-Al(i-Bu)_3-pyridine

The phase states of the catalytic system of FeCl3-Al（i-Bu）3-pyridine are studied in the paper by means of the Tyndall effect, electron microscopy and super-filtration. It is found that the catalyst dispersing in the butadienehydrogasoline solution exists in small particles and the size of particle is 30 nm or so in diameter. The catalyst belongs to a multi-phase catalytic system. The active center of catalyst lies on the surface of nanometer particles, which are amorphous. The ratios of different components of catalyst affect the formation of the particles. With the optimum ratio, nanometer particles, which disperse more uniformly and are of highly catalytic activity, can be obtained.

Phase diffusion of a two-component Bose-Einstein condensates:exact and short-time solutions for arbitrary coherent spin state

We investigate phase diffusion of a two-component Bose--Einstein condensates prepared initially in arbitrary coherent spin state ｜θ0,φ0｜. Analytical expression of the phase-diffusion time is presented for θ0～π/2 case. In comparison with the symmetrical case （i.e., θ0=π/2）, we find that the diffusion process becomes slow due to the reduced atom number variance.

Representation of Phase Behavior of Ionic Liquids Using the Equation of State for Square-well Chain Fluids with Variable Range

为有为化学协会基于统计力学开发的可变范围(SWCF-VR ) 的方形井的链液体的状态(曙光女神) 的一个方程为 pressure-volume-temperature (pVT ) 和纯离子的液体(IL ) 和他们的混合物的阶段平衡的计算被采用。为 23 IL 的新分子的参数被在宽温度和压力范围上适合他们的试验性的密度数据获得。 IL 的分子的参数相应器官的阳离子和一个相同阴离子例如创作了[ C x mim ][ NTf 2]好关于他们的分子的重量线性，显示相应物质的分子的参数，当没有试验性的数据是可得到的时，随后， pVT 和蒸汽液体 equilibria 蒸汽液体 equilibria ( VLE )能用概括参数被预言。参数的新集合令人满意地在仅仅使用一个温度无关的二进制相互作用参数的低压力在各种各样的 IL 为溶剂和 IL 混合和气体的溶解度的性质的计算被使用。

Non-equilibrium State Salt-forming Phase Diagram：Utilization of Bittern Resource in High Efficiency

Salt-forming regions for a complex salt-water system in non-equilibrium state of evaporation process are usually different from those in solubility diagrams.To understand the solid-forming region of NaCl and improve the utilization of bittern resources,experiments were carried out to evaporate 20 representative mixture solution samples of Na +,Mg 2+ //Cl-,2 4 SO-H2O system with an average evaporation intensity of(1.4±0.4) g·L-1 ·min-1(water) at boiling temperature 348 K,and determine the NaCl solid-forming regions in non-equilibrium state.Because of the complexity of salt-forming region,a maximal region and a minimal region were proposed to express the non-equilibrium state salt-forming region with different crystal seed,and a conditional salt-forming region was proposed to present the characteristic region of non-equilibrium salt-forming phase diagram.The areas of the maximal and minimal regions are 2.00 and 1.56 times those in solubility diagram,so it is possible to utilize bittern resources in high efficiency.The recovery rates of NaCl were 99.65%,93.14%,88.57%,72.76%,and 83.68%for six typical bittern sources from Tulantai Salt Lake(China),Dongtai Salt Lake(China) ,Jilantai Salt Lake(China),Qarun Salt Lake(Egypt) and seawater,respectively.It is testified that the non-equilibrium state salt-forming phase diagram can be used in industrial processes.

Effects of high-pressure heat treatment on the solid-state phase transformation and microstructures of Cu_(61.13)Zn_(33.94)Al_(4.93) alloys

The phase transformation activation energy of the Cu61.13Zn33.94A14.93 alloys, which were treated at 4 GPa and 700 ℃ for 15 minutes, was calculated by means of differential scanning calorimetry curves obtained at various heating and cooling rates. Then, the effects of high-pressure heat treatments on the solid-state phase transformation and the microstructures of Cu61.13Zn33.94A14.93 alloys were investigated. The results show that high-pressure heat treatments can refine the grains and can change the preferred orientation from （111） to （200） of α phase. Compared with the as-cast alloy, the sample with high-pressure heat treatment has finer grains, lower β＇→β and/β→β＇ transformation temperature and activation energy. Furthermore, we found that high cooling rate favours the formation of fine needle-like α phase in the range of 5-20℃/min.

Ground-State Phase Diagram of Transverse Spin-2 Ising Model with Longitudinal Crystal-Field

<正> The transverse spin-2 Ising ferromagnetic model with a longitudinal crystal-field is studied within themean-field theory based on Bogoliubov inequality for the Gibbs free energy.The ground-state phase diagram and thetricritical point are obtained in the transverse field Ω/zJ-longitudinal crystal D/zJ field plane.We find that there are thefirst order-order phase transitions in a very small range of D/zJ besides the usual first order-disorder phase transitionsand the second order-disorder phase transitions.

NON-CUBIC EQUATION OF STATE FOR PHASE EQUILIBRIUM CALCULATIONS

A new non-cubic equation of state is proposed for calculation of the thermodynamic properties ofnonpolar and polar fluids and their mixtures,including,saturated vapor pressure,saturated liquid volume,saturated vapor volume,heats of vaporization and vapor-liquid equilibria.The new equation is derived from thegeneralized van der Waals partition function in which the repulsive terms are expressed with the Carnahan andStarling equation for hard spheres,and the attractive terms are made up of the dispersive energy and theChemical association energy. The rules of dependence of parameters α and σ and on temperature are considered broadly so that the newequation yields good agreement with experimental saturated properties of 20 nonpolar and 27 polar fluids in therange of reduced temperatures of 0.5 to 1.0 The new equation with parameters group-contributed generally givessatisfactory predictions on saturated properties. Correlations of vapor-liquid equilibrium data for alcohol-containing systems by using van

Phase-sensitive fat suppression steady-state free procession sequence with phase correction

Robust and fast fat suppression is a challenge in balanced steady-state free precession （SSFP） magnetic resonance imaging. Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short scan time, phase errors, especially spatially-dependent phase shift, caused by a variety of factors may result in misplacement of fat and water voxels. In this paper, a novel phase correction algorithm was used to calibrate those phase errors during image reconstruction. This algorithm corrects phase by region growing, employing both the magnitude and the phase information of image pixels. Phantom and in vivo imagings were performed to validate the technique. As a result, excellent fat-suppressed images were acquired by using single-acquisition phase-sensitive SSFP with phase correction.

PHASE EQUILIBRIUM OF COMPLEX MIXTURES WITH EQUATIONS OF STATE:AN UPDATE

Here we review a new class of mixing rules that have extended range of mixtures and condi-tions that can now be described by equation of state models.One characteristic of these mixing rulesis that they simultaneously satisfy the boundary conditions of producing a second virial coefficientthat is quadratic in mole fraction,and a free energy of mixing like that of an activity coefficientmodel at high density,though the mixing rule is itself independent of density.We show that usingthis mixing rule,various asymmetric,highly nonideal mixtures can be accurately described.Oneserendipitous result is that the parameters in this mixing rule model are almost independent oftemperature,which allows accurate extrapolations of phase behavior to be made over large ranges oftemperature and pressure.

Structure phase transformation and equation of state of cerium metal under pressures up to 51 GPa

This study presents high pressure phase transitions and equation of states of cerium under pressures up to 51 GPa at room temperature. The angle-dispersive x-ray diffraction experiments are carried out using a high energy synchrotron x-ray source. The bulk moduli of high pressure phases of cerium are calculated using the Birch-Mumaghan equation. We discuss and correct several previous controversial conclusions, which are caused by the measurement accuracy or personal explanation. The c/a axial ratio of e-Ce has a maximum value at about 29 GPa, i.e., c/a ≈ 1.690.

Phase properties of odd and even circular states

Phase properties of the even and odd circular states are studied within the Hermitian phase formalism of Pegg and Barnett. Exact analytical formulas for the distribution function and the variance of the phase operator are obtained and used to examine whether or not the even and odd circular states exhibit photon-number squeezing and phase squeezing.

Resonant interaction scheme for GHZ state preparation and quantum phase gate with superconducting qubits in a cavity

A scheme is proposed to generate GHZ state and realize quantum phase gate for superconducting qubits placed in a microwave cavity. This scheme uses resonant interaction between the qubits and the cavity mode, so that the interaction time is short, which is important in view of decoherence. In particular, the phase gate can be realized simply with a single interaction between the qubits and the cavity mode. With cavity decay being considered, the fidelity and success probability are both very close to unity.

Phase Properties of Nonlinear Coherent States

Using the Pegg-Barnett fornalism we study the phase probability distributions and the squeezing effects ofmeasured phase operators in the nonlinear coherent states introduced by R.L. de Matos Filho and W. Vogel to describethe center-of mass motion of a trapped ion and the q-coherent states. Moreover, we have obtained the completenessrelation of nonlinear coherent states and proved that the q-Fock state |n>q introduced in many papers is, in fact, theusual Fock state.

Quantum phase distribution and the number-phase Wigner function of the generalized squeezed vacuum states associated with solvable quantum systems

The quantum phase properties of the generalized squeezed vacuum states associated with solvable quantum systems are studied by using the Pegg-Barnett formalism.Then,two nonclassical features,i.e.,squeezing in the number and phase operators,as well as the number-phase Wigner function of the generalized squeezed states are investigated.Due to some actual physical situations,the present approach is applied to two classes of generalized squeezed states：solvable quantum systems with discrete spectra and nonlinear squeezed states with particular nonlinear functions.Finally,the time evolution of the nonclassical properties of the considered systems has been numerically investigated.