We introduce a hybrid cavity optomechanical model capable of generating significant genuine tripartite interactions and entanglement among coherent degrees of freedom.However,realizing and controlling such tripartite interactions and their entanglement pose crucial challenges that remain largely unexplored.In this work,we predict a tripartite coupling mechanism within a hybrid quantum system consisting of a vibrating mechanical oscillator,a two-level atom and a single-frequency cavity field.We specifically propose a mechanism for tripartite and cross-Kerr nonlinear coupling through displacement and squeezing transformations.By adjusting the optical amplitude of the pump light,we can effectively enhance these nonlinear couplings,facilitating the manipulation of entangled and squeezed states.The resulting tripartite genuine entanglement exhibits distinct evolutionary characteristics.Notably,when the pump light amplitude is large,the tripartite entanglement persists for longer time.Additionally,the phonon displays characteristics of both cooling and squeezing.Our study presents a pathway for exploring and exploiting controllable multipartite entanglement,as well as achieving phonon cooling and squeezing with the assistance of a mesoscopic harmonic oscillator.This work underscores the innovative potential of our model in advancing the field of optomechanics and quantum entanglement.

The fascinating properties arising from the interaction between different ferroic states of two-dimensional (2D) materials have inspired tremendous research interest in the past few years. Under the first-principles calculations, we predict the coexistence of antiferromagnetic and ferroelastic states in VOX (X = Cl, Br, I) monolayers. The results illustrate that the VOX monolayers exhibit indirect bandgap characteristics, i.e., their gaps decrease with the halide elements changing from Cl to I. The ground states of all these VOX monolayers are antiferromagnetic (AFM) with the magnetic moments contributed by the V 3d electrons. Furthermore, the magnetic ground state changing from AFM to ferromagnetism (FM) can be realized by doping carriers. In addition, the moderate ferroelastic transition barrier and reversible switching signal ensure their high performances of nonvolatile memory devices. Our findings not only offer an ideal platform for investigating the multiferroic properties, but also provide candidate materials for potential applications in spintronics.

Gas chromatography-mass spectrometry (GC-MS), which can separate and quantify thousands of individual petroleum biomarker compounds, is generally acknowledged as the most powerful technique for oil fingerprinting nowadays. Traditional oil fingerprint studies employ the whole suite of biomarkers measured in chromatographic analysis, which is prone to introducing ambiguous variables in the whole set and being time and labour intensive. To extract the most representative and meaningful indicators for the oil fingerprinting and identification, this paper proposes a method based on principal component difference to select a simplified set of biomarkers, providing the possibility of faster elution and analysis procedures. For the purpose of further verifying the reliability and accuracy of our method, identification simulation experiments including principal component analysis (PCA) spatial clustering, hierarchical clustering, and generalized regression neural network are carried out with the whole set and the simplified set of biomarkers, respectively. All the results and analyses demonstrate that the simplified set of biomarkers selected by our proposed method can achieve almost the same or even better identification results than those of the whole set of biomarkers.

Gas chromatography–mass spectrometry (GC–MS), which can separate and quantify thousands of individual petroleum biomarker compounds, is generally acknowledged as the most powerful technique for oil fingerprinting nowadays. Traditional oil fingerprint studies employ the whole suite of biomarkers measured in chromatographic analysis, which is prone to introducing ambiguous variables in the whole set and being time and labour intensive. To extract the most representative and meaningful indicators for the oil fingerprinting and identification, this paper proposes a method based on principal component difference to select a simplified set of biomarkers, providing the possibility of faster elution and analysis procedures. For the purpose of further verifying the reliability and accuracy of our method, identification simulation experiments including principal component analysis (PCA) spatial clustering, hierarchical clustering, and generalized regression neural network are carried out with the whole set and the simplified set of biomarkers, respectively. All the results and analyses demonstrate that the simplified set of biomarkers selected by our proposed method can achieve almost the same or even better identification results than those of the whole set of biomarkers.

A symmetric grating is proposed to obtain higher output power in spectral beam combination by increasing the number of lasers and spectral utilization. The grating allows laser beams to be incident from both sides of the grating normal to achieve coaxial beam combining, so the number of beams and the combined output power are doubled compared with the traditional grating under the same spectral line-width. The grating is designed with the central wavelength of 4.65 μm, and the calculation results show that this grating is very advantageous for spectral beam combining, especially for the light waves in the range 4.55–4.71 μm, where their diffraction efficiencies are high (over 80%) and correspond to a wide and linear range of incidence angles. Meanwhile, based on the symmetric gratings we further propose a circular grating to achieve the same frequency spectral beam combining. This beam combining design will not increase the laser spectral line width while enhancing the laser power, reducing the requirements for the unit laser spectral line width, which is very meaningful in some application fields and will further enrich the research of spectral beam combining.

We perform calculations for the most stable structures of AlnP13−n semiconductor binary clusters with n = 0–13 by using genetic algorithm combined with density functional theory calculations. New lowest-lying AlnP13−n clusters (n = 1–11) are found. It is shown that Al12P1 favors slightly distorted icosahedra structure having a vertex phosphorus atom, not previously reported the icosahedra structure with a central phosphorus atom. The geometric structure and electronic properties are discussed. The results show that the binding energy increases monotonically with the increase in the number of aluminum atoms. The odd even oscillation curve of the second-order difference of total energy is reversed when the number of aluminum atoms n = 8. Al4P9 has relatively large second-order energy difference, large ionization energy, and large hardness, which is considered to be more chemically stable than other mixed clusters of AlnP13−n (n = 1–12) in our calculation. These results establish a more complete picture for the structural evolution of the medium-sized aluminum phosphorus clusters.

Two-dimensional ferromagnetic semiconductors have received extensive attention due to their promising application for valleytronics along with the opportunity to realize spontaneous valley polarization. Herein, by means of the first-principles calculations, we design a two-dimensional ferromagnetic semiconductor single-layer VSCl with the direct band gap is 0.88 eV, and magnetic moment is 2 mu(B) per unit. The Curie temperature of single-layer VSCl is estimated to be 125 K based on the mean field approximation. In addition, the ferromagnetism can be further improved by adopting moderate tensile strain. Importantly, the intrinsic breaking of time and spatial inversion symmetry leads to the spontaneous valley polarization in single-layer VSCl. The corresponding valley polarization energy is about 57.8 meV, which is sizeable enough for practical operations. Our findings provide a candidate material for realizing the potential application of two-dimensional valleytronic devices.

Density functional theory calculations have been performed to study the geometrical structures and electronic properties of Pn - 1Al cage clusters in the range of n = 20-40 atoms. The structures of the cage Pn - 1Al are deformed at the doping position due to the doping of aluminum, but they are still cage shape in general. Most of these cage structures are composed of slightly distorted pentagons and hexagons. In the Pn - 1Al cage clusters studied in this work, P19Al has relatively excellent properties. The binding energy, ionization potential, electron affinity, electrostatic potential, hardness, aromaticity, bond length, HOMO and LUMO orbital, Mulliken charge and density of states of these clusters are discussed.

Numerous efforts have been paid on n-type Mg3Sb2-based Zintl compounds with exceptional thermoelectric performance, but seldom on p-type sample with poor electrical transports. In this work, we investigate the electronic structure and transport properties of p-type Mg3Sb2 by using first-principles method and Boltzmann transport theory. Firstly, the slightly higher low-temperature electrical conductivity for theoretical calculations than experimental results suggest that different from n-type sample, the contribution of eliminating grain boundary scattering to electrical transports is weak in p-type Mg3Sb2. Secondly, the calculated higher Seebeck coefficient along x-axis and higher electrical conductivity along z-axis reveal the anisotropy of electrical transports, and this phenomenon may be ascribed to the anisotropic carrier's effective masses. Because the gradual leading role of Seebeck coefficient as temperature increasing, the peak power factor along x-axis exceeds that along z-axis at temperature above similar to 500 K, which indicates that further improvement of the electrical performance can be expected through anisotropic transports. Thirdly, the effect of the adsorption of oxygen atom on Mg3Sb2 (001) surface on the electronic structure are investigated. This work aims to provide new insight into the optimization of p-type electrical transport property, thereby closing the gap with n-type property for developing Mg3Sb2-based thermoelectric devices.

Experimental results show an intriguing phenomenon that although Bi and Sb have the same number of valence electrons, Bi/Sb substitution increases the electron concentration of n-type Mg3Sb2-based materials. Using a combination of theoretical calculations and experimental synthesis, this work reveals the physical mechanism of the effect of Bi doping on carrier concentration. The increase in electron concentration mainly originates from the enhanced degree of ionization of donor impurity because of the decrease of conductivity effective mass and increase of dielectric constant caused by the narrowing of bandgap with Bi doping. Based on the collaborative optimization of the electrical and thermal transports, n-type Mg3.175Mn0.025Sb1.48Bi0.48Te0.04 exhibits the best thermoelectric performance with a peak zT of 1.85 at 725 K and an average zT of 1.21. This work demonstrates an effective strategy of bandgap engineering for the optimization of carrier concentration and provides insightful guidance for designing other thermoelectric materials.

基于non-Kolmogorov大气湍流谱理论,建立了双量子比特路径纠缠态在大气湍流中传输的数学模型,获得其纠缠退化的解析表达式,并进行了数值仿真.研究结果表明:当空间距离分布较小的双量子比特路径纠缠态在大气湍流中传输时,其纠缠度的保真度较高;同时,较长波长的纠缠光在折射率功率谱指数α较大、广义湍流折射率结构起伏结构函数(C)2n较大的non-Kolmogorov大气湍流中传输保真度较高.所建立的远距离纠缠态传输模型可定量分析纠缠退化问题,为自适应低误码率的远距离大气量子通信提供了可靠的理论参考.

随着固体激光技术发展以及啁啾脉冲放大技术加持,激光峰值功率得到极大的提高,促进了激光物质相互作用领域的研究并衍生出若干具有很好前景的应用.激光驱动的台面级离子加速器便是其中重要的应用领域之一.激光加速的质子具有源体积小、脉冲时间短和时间分辨高等特点,可以广泛应用于成像、医疗及科研领域,并能有效降低这些领域的相关成本,促进其高效发展.影响获得优质离子束的条件很多,文中从靶形状及与激光作用后形成的等离子体性质角度对近期该研究方向的一些进展进行了总结及展望.

Ultraviolet photodetectors have attracted significant research attention in recent years due to their potential applications in civilian and military fields. ZnO nanowires and nanorods have been regarded as the most potential candidates for ultraviolet photodetectors fabrication because of their peculiar characteristics and size effect, which are different from their bulk material. Recently, many novel routes and semiconductor features, such as the surface and interface engineering, the pryo-phototronic effect, the piezo-phototronic effect, the surface plasmon effect and the surface functionalization have been utilized to improve the photoelectric characteristics of ultraviolet photodetectors. Thus, the working mechanism of these effects existing in ZnO nanowires/nanorods-based ultraviolet photodetectors should be investigated in-depth. In this paper, firstly, the hydrothermal method and the chemical vapor deposition method, as two typical synthesis methods of ZnO nanowires are briefly reviewed. Secondly, we focus on reviewing the properties of varied ZnO nanowires/nanorods-based ultraviolet photodetectors constructed using the above mentioned semiconductor features with metal-semiconductor-metal structure, Schottky barrier structure, vertical p-n heterojunction structure and core-shell heterostructure. Furthermore, the most attractive self-powered ultraviolet photodetectors are systematically reviewed. For various ZnO nanowires/nanorods-based ultraviolet photodetectors, we put the emphasis on the working mechanism of semiconductor features to improve the properties of the photodetectors. Finally, we give an outlook on the future development of ZnO nanowires/nanorods-based ultraviolet photodetectors.

Based on the theory of Kolmogorov oceanic turbulence spectrum and quantum optics, the theoretical model that the spatial two-qubit photons entangled states prepared by parametric dowry-converted propagate through the Kohnogorov oceanic turbulence is constructed. The theoretical expressions for entanglement degradation of the spatial two-qubit photons entangled states in oceanic turbulence are obtained. Then, using the Wootters's concurrence, the influence of Kolmogorov oceanic turbulence on the spatial two-qubit photons entangled states with numerical simulation is analyzed. The results show that the parameters of the laboratory device which are prepared the spatial two-qubit entangled states will make a great impact on the entanglement. And the smaller separation of two signal (idler) apertures or the separation between the two signal and the idler apertures is, the higher fidelity of the spatial two-qubit photon entangled states is. The entanglement of spatial two-qubit states can well maintain in the salinity-induced oceanic turbulence when the rate of dissipation of mean-square temperature is small and the rate of dissipation of turbulent kinetic energy per unit mass of fluid is big with numerical calculation. These results have important significance for tong distance underwater quantum communication via quantum entangled channel.

Based on the quantum technique of the weak measurement and quantum measurement reversal (WMR), we propose a scheme to protect entanglement for an entangled two-qubit pure state from four typical quantum noise channels with memory, i.e. , the amplitude damping channel, the phase damping channel, the bit flip channel, and the depolarizing channel. For a given initial state | ψ 〉 = a | 00 〉 + d | 11 〉, it is found that the WMR operation indeed helps to protect entanglement from the above four quantum channels with memory, and the protection effect of WMR scheme is better when the coefficient a is small. For the other initial state | ϕ 〉 = b | 01 〉 + c | 10 〉, the effect of the protection scheme is the same regardless of the coefficient b and the WMR operation can protect entanglement in the amplitude damping channel with memory. Moreover, the protection of entanglement in quantum noise channels without memory in contrast to the results of the channels with memory is more effective. For | ψ 〉 or | ϕ 〉, we also find that the memory parameters play a significant role in the suppression of entanglement sudden death and the initial entanglement can be drastically amplified. Another more important result is that the relationship between the concurrence, the memory parameter, the weak measurement strength, and quantum measurement reversal strength is found through calculation and discussion. It provides a strong basis for the system to maintain maximum entanglement in the nosie channel.

We investigate the entanglement protection of a qutrit-qutrit system under local amplitude damping channels by weak measurement and measurement reversal. We examine the Δ-type of initially entangled qutrit-qutrit states. We find that the entanglement decays with the decoherence strength increasing for the qutrit-qutrit state. Therefore, we focus on how to protect the quantum entanglement from decoherence by weak measurement and measurement reversal. Our results show that we can prevent amplitude damping decoherence by the combination of prior weak measurement and post optimal measurement reversal comparing with the dynamics without protection. Regardless of the value of decoherence, the protection scheme has better effect on the kind of V-configuration. And with the increase of decoherent strength, the difference is more obvious. Another interesting result is that the enhancement of the entanglement is very weak when decoherent strength is zero.

Low-dimensional all-inorganic metal halide perovskite (AIMHP) materials, as a new class of nanomaterials, hold great promise for various optoelectronic devices. In the past few years, tremendous progress has been achieved in the development of efficient and stable AIMHP nanomaterials for optical property studies and related applications. Here, we offer a critical overview on the unique merits and the state-of-the-art design of AIMHP using different composition strategies. Then, the effects of material compositions, dimensionality, morphologies and structures on optical properties are summarized. We also comprehensively present recent advances in the development AIMHP nanomaterials for practical applications including solar cells, light-emitting diodes, lasers and photodetectors. Lastly, the critical challenges and future opportunities in this emerging field are highlighted.

Type-I clathrate compounds Yb x Ba8-x Ga16Ge30 have been synthesized by the high-pressure and high-temperature (HPHT) method rapidly. The effects of the synergy of atom filling and pressure regulation on the microstructure and thermal and electrical properties have been investigated. With the content of Yb atom increasing, the carrier concentration is improved, the electrical resistivity and the absolute Seebeck coefficient are decreased, while the thermal conductivity is reduced significantly. A series of extremely low lattice thermal conductivities are achieved, attributed to the enhancement of multiscale phonon scattering for the "rattling" of the filled guest atoms, the heterogeneous distribution of nano- and microstructures, grain boundaries, abundant lattice distortions, lattice deformations, and dislocations. As a result, a maximum ZT of about 1.07 at 873 K has achieved for the Yb0.5Ba7.5Ga16Ge30 sample.

Si-based clathrate thermoelectric (TE) materials composed of low-cost, nontoxic, lightweight, and earth-abundant elements are typical representatives of cheaper thermoelectric materials. However, synthesis is difficult, and the relatively low ZT values are the barriers hindering the further development of the silicon clathrates. So, it is necessary to explore an alternative synthetic method and improve the ZT values simultaneously. In this work, Si-based clathrate Ba8Cu6Si40 samples have been synthesized by a simple, rapid, and feasible HPHT method with 25 min. We have investigated the changes of the TE properties and microstructures depending on the pressure in detail. The power factor has been increased due to the decreased carrier concentration, meanwhile, the thermal conductivity has been cut down on account of the strengthened full-spectrum-phonons scattering resulting from the multiple and multiscale microstructures by high-pressure processing. Ultimately, a relatively good ZT value 0.31 is achieved at 773 K for the sample synthesized at 4 GPa. To the best of our knowledge, it is higher than all of the results of pure Si-based Ba8Cu6Si40 compounds formed by other methods.

Ardehali (Phys. Rev. A, 46, 5375 (1992). 10.1103/PhysRevA.46.5375) derived a Bell-type inequality for an n-particle system in a Greenberger–Horne–Zeilinger (GHZ) state. This inequality helps relax ...