The selective coherent destruction of tunneling (CDT) of ultracold Bose gas with three-particle interactions in a modulated double-well potential is discussed. It is shown that the effects of two- and three-particle interactions on the dynamics of the selective CDT are strongly coupled and the three-particle interactions significantly modify the selective CDT. For weak three-particle interactions, an upper bound of the boson number for realizing the selective CDT exists and the region of boson number for realizing the selective CDT is enlarged (reduced) with repulsive (attractive) three-particle interactions. For strong three-particle interactions, the boson number in the system for realizing the selective CDT not only has an upper bound, but also has a lower bound. The results are confirmed by numerical simulations.

Using the generalized formalism of Dalibard, Dupont-Roc and Cohen-Tannoudji we investigate the spontaneous excitation of a static atom interacting with electromagnetic vacuum fluctuations outside an Einstein Gauss-Bonnet black hole in d-dimensions. It shows that spontaneous excitation does not occur in a Boulware vacuum, while exists in an Unruh vacuum and Hartle–Hawking vacuum. As to the total rate of change of the atomic energy, it does not receive the contribution from the coupling constant of the Gauss–Bonnet term at spatial infinity, only the dimensional parameter has the contribution to it. Near the event horizon, both the coupling constant and the dimension p contribute to the total rate of change of the atomic energy in all three kinds of vacuum. We discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime lastly.

We investigate the dynamics of the Kuramoto model on complex networks with part of the oscillators subjected to an external drive. It is found that the mutual synchronization is attracted to the drive when the frequency of the drive is close to the mean frequency of oscillators and, otherwise, mutual synchronization coexists with the driven synchronization. We also find that the synchronization between the mutual synchronization and the driven synchronization is dependent on the network topology when the coupling strength among oscillators is far away from the global synchronization in the absence of the drive. The transition is continuous on Erd?s-Rényi networks while it is discontinuous on scale free networks.

In accordance with the recent experimental progress of the controllable spin-spin interactions, the Heisenberg model after an interaction quench is discussed. The Hamiltonian of the system out of equilibrium is introduced and treated by the flow equation method. As a result, the spectrum and zero-point spin deviation are obtained with the help of time-evolved operators. Additionally, other methods are applied to verify the results in mathematics. It is found that the observables show an oscillating behavior. The feasible experimental scheme of the concerned scenario is also mentioned.

We report theoretical calculations of the transition probability errors introduced by microwave leakage in Cs fountain clocks, which will shift the clock frequency. The results show that the transition probability errors are affected by the Ramsey pulse amplitude, the relative phase between the Ramsey field and the leakage field, and the asymmetry of the leakage fields for the upward and downward passages. This effect is quite different for the leakage fields presenting below the Ramsey cavity and above the Ramsey cavity. The leakage-field-induced frequency shifts of the NIM5 fountain clock in different cases are measured. The results are consistent with the theoretical calculations, and give an accurate evaluation of the leakage-field-induced frequency shifts, as distinguished from other microwave-power-related effects for the first time.

Detection resolution is crucial for improvement of the measurement precision in the device and instrument. Because of the limited resolution, a fuzzy area with the truth-value as its center is found during the detection. The finding for improving the measurement precision by the border of fuzzy area is first introduced. The higher resolution can be captured by the higher resolution stability which makes the different detection results of the inner and outer fuzzy area on the border reflected more sensitively between the measure and the reference quantity. The system resolution obtained only depends on the stability of measurement resolution, which is much better than the measurement resolution itself. Based on the finding, the measurement precision can be improved two or three orders of magnitude. The finding can be used in various kinds of high precision measurement.

A strong magnetic field (over 1000 T) was recently experimentally produced at the Academy of Engineering Physics in China. The theoretical methods, which include a simple model and MHD code, are discussed to investigate the physical mechanism and dynamics of generating the strong magnetic field. The analysis and simulation results show that nonlinear magnetic diffusion contributes less as compared to the linear magnetic diffusion. This indicates that the compressible hydrodynamic effect and solid imploding compression may have a large influence on strong magnetic field generation.

We present the simulation and characterization of several aluminium three-dimensional (3D) resonators, which can be used for superconducting quantum computation. By changing the conductivity of the aluminium in a high frequency structure simulator, the loaded quality factor at room temperature and base temperature (20 mK) can be simulated. From S₂₁ measurement, we can characterize the properties of the resonators. The simulated and experimental results can be fitted well by exponential equations.

The tensor force effect on potential energy surfaces of the N=28 neutron-rich isotones is investigated by using the deformed Skyrme–Hartree–Fock–Bogoliubov approach with the T22 interaction. It is found that, without the tensor force, ⁴⁰Mg and ⁴⁶Ar have prolate and spherical ground states, respectively. The ground states of ⁴²Si and ⁴⁴S are oblate. The shape coexistence in ⁴⁰Mg, ⁴²Si and ⁴⁴S is evident. However, the ground state deformations of these isotones are not changed and the shape coexistence in ⁴²Si and ⁴⁴S vanishes when the tensor force is switched on. Taking ⁴²Si as an example, the disappearance of the shape coexistence is understood by analyzing the tensor force effect on the shell correction energies.

We study the geometric scaling in the new combined data of the hadron-electron ring accelerator by using the Golec-Biernat–Wüsthoff model. It is found that the description of the data is improved once the high accurate data are used to determine the model parameters. The value of x₀ extracted from the fit is larger than the one from the previous study, which indicates a larger saturation scale in the new combined data. This makes more data located in the saturation region, and our approach is more reliable. This study lets the saturation model confront such high precision new combined data, and tests geometric scaling with those data. We demonstrate that the data lie on the same curve, which shows the geometric scaling in the new combined data. This outcome seems to support that the gluon saturation would be a relevant mechanism to dominate the parton evolution process in deep inelastic scattering, due to the fact that the geometric scaling results from the gluon saturation mechanism.

Based on the modified isospin-dependent quantum molecular dynamics model, the number of emitted nucleons in a photonuclear reaction is studied with different symmetry potentials and different isospin-dependent nucleon-nucleon (N–N) collision cross sections. It is found that the number of emitted nucleons is sensitive to the isospin-dependent nucleon-nucleon cross section when the photon's energy is higher than 150 MeV, while it is insensitive to symmetry potential. The number of emitted neutrons is more sensitive to N–N collision cross sections than that of protons. It is realized that the number of emitted neutrons can be used as a sensitive probe to extract the information of the isospin-dependent N–N cross section at high energy photonuclear reactions.

The inner-shell 2p_3/2 ionization of Mg-like Fe¹⁴⁺, Cd³⁶⁺, W⁶²⁺ and U⁸⁰⁺ ions by linear polarized light and the subsequent radiative decay are studied theoretically with the multiconfiguration Dirac–Fock (MCDF) method and the density matrix theory. Special attention is paid to exploring the influence of the polarization properties of the incident photon and the non-dipole term which arises from the multipole expansion of the electron-photon interaction on the properties of the subsequent x-ray radiation. The results show that there is a linear relationship between the degree of linear polarization of the radiative decay and ones of the incident light, which can be used for diagnosing the polarization of a light source. In addition, with the increasing photon energies, the non-dipole contribution to the alignment of the residual ions, the degree of linear polarization, as well as the angular distribution of the radiative decay following the inner-shell photoionization will also be increased.

Through an analysis of the nearest neighbor level spacing statistics for atoms in parallel electric and magnetic fields, we investigate the evolution of the electron dynamics as electric field strength increases. In the 'inter-l mixing' predominant region, the electron shows complex dynamics while in the 'inter-n mixing' predominant region, its dynamics behaves in a relatively stable way and the characteristic quantity ξ shows a slight oscillation. Comparing the dynamics for hydrogen and barium, we find that the core effect makes the main contribution to the chaotic behavior in non-hydrogen atoms.

The atomic number densities of ⁸⁷Rb vapor and surrounding gas ³He in a sealed cubic cell were measured by sweeping the absorption line and fitting the experimental data with a Lorentzian profile. The absorption was carried out around the D1 transition at different temperatures. We compare our results for the number density for⁸⁷Rb with the previous methods and calculate the fractional error to be less than 5% as well as the error for ³He between this work and the density obtained from the filling procedure to be no more than 4.2% at 370 K. In addition, we discuss the factors that contribute to the error, among which the cell temperature plays the most important role.

We investigate the behavior of two-dimensional (2D) atom localization in a three-level cascade-type atomic system via measuring the probe absorption. It is found that the precision of the atom localization can be improved by adjusting probe detuning and coupling a coherent coupling field and standing-wave fields to the same atomic transition. Remarkably, a single localization peak can be obtained by adjusting appropriate system parameters, and some corresponding explanations are also given.

The separate contributions of the two nuclei in H⁺₂ to the harmonic generation are investigated by numerically solving the time-dependent Schr?dinger equation. The results show that the diverse electron distributions around the two nuclei under the effect of a laser field lead to different contributions of the two nuclei to the harmonic generation in different times, i.e., the contribution mainly comes from nucleus A around the (n+0.5) optical cycle while from nucleus B around the n optical cycle. By means of the time-frequency distributions and the coupled electron nuclear wave-packet density distributions, the physical mechanism is discussed in detail.

A high-power high-efficiency laser power transmission system at 100 m based on an optimized multi-cell GaAs converter capable of supplying 9.7 W of electricity is demonstrated. An I–V testing system integrated with a data acquisition circuit and an analysis software is designed to measure the efficiency and the I–V characteristics of the laser power converter (LPC). The dependencies of the converter's efficiency with respect to wavelength, laser intensity and temperature are analyzed. A diode laser with 793 nm of wavelength and 24 W of power is used to test the LPC and the software. The maximum efficiency of the LPC is 48.4% at an input laser power of 8 W at room temperature. When the input laser power is 24 W (laser intensity of 60000 W/m²), the efficiency is 40.4% and the output voltage is 4 V. The overall efficiency from electricity to electricity is 11.6%.

A new design idea for a monopole acoustic transducer which increases the frequency band and improves electromechanical performance is proposed with a focus on the lowest order of the radial and flexural modes. Numerical modeling of the resonance frequencies and electrical conductance are conducted with respect to the dimensions and material parameters of the proposed transducer. The transmitting voltage response level with respect to the density and velocity of the fluid media is calculated. The numerical simulation is validated through experiments. The frequency band and the electromechanical performance of the monopole acoustic transducer can be optimized by the given methods concluded from the numerical results.

Dispersion relations of Love mode acoustic guided waves propagation in Pb(Mg_1/3Nb_2/3)O₃–33%PbTiO₃ (PMN-0.33 PT) single crystal with a gold electrode film are calculated. There is no cross coupling among Love wave modes, which is conducive to eliminating the cross interference between modes. The general formula is derived to precisely measure the thickness of the electrode. More acoustic energy would be concentrated inside the electrode with the increase of film thickness for a given frequency. Compared with the PZT-5 ceramic, [001]_c poled PMN-33%PT single crystal has a slower attenuation of the amplitude of the acoustic guided wave. Therefore, single crystal is extremely suitable for making low loss acoustic wave devices with a high operating frequency.

Repetitive impurity snake modes are observed after H–L mode transitions (high to low confinement modes) in EAST plasmas exhibiting multiple H–L–H transitions. Such snake modes are observed to lower the core plasma toroidal rotation. A critical impurity strength factor associated with snake-mode formation is estimated to be as high as α_Z,c =n_Z,c Z²/n_e ～0.75. These observations have implications for ITER H-mode sustainability when the heating power is only slightly above the H-mode power threshold.

The mode transition of a pulsed vacuum arc discharge, which is from vacuum surface flashover to non-surface vacuum breakdown or vice versa, is studied by simply adjusting a trigger resistor. This approach provides a possibility to research the transition discharge process. Since the transition process is smooth and controllable, the transition mechanism and its effect on the performance of an ion source can be investigated via various diagnosis experiments. The experimental results show that the mode transition occurs when the resistance is in the range of 0–10 Ω. With the mode transition from surface flashover to non-surface vacuum breakdown, the vacuum arc discharge becomes more intense and the ion current produced by the Ti cathode ion source increases by two times. The related physical mechanism is also discussed in detail.

Systematic investigations are performed on a set of Al_xGa1−xN/GaN heterostructures grown by metalorganic chemical vapor deposition on sapphire (0001). The Al composition x is determined by Rutherford backscattering. By using high resolution x-ray diffraction and the channeling scan around an off-normal <1213> axis in {1010} plane of the AlGaN layer, the tetragonal distortion e_T caused by the elastic strain in the epilayer is determined. The results show that e_T in the high-quality AlGaN layers is dramatically influenced by the Al content.

Single crystals of pure SnS, indium (In) and antimony (Sb) doped SnS are grown by the direct vapor transport technique. Two doping concentrations of 5 at.% and 15 at.% are employed for both In and Sb dopants. In total, five samples are studied, i.e., pure SnS, 5 at.% In-doped SnS, 15 at.% In-doped SnS, 5 at.% Sb-doped SnS and 15 at.% Sb-doped SnS single crystals. The energy dispersive analysis of x-ray (EDAX) and x-ray diffraction (XRD) analysis show that all the five as-grown single crystal samples possess near perfect stoichiometry and orthorhombic structure, respectively. The doping of In and Sb in SnS is established from the EDAX data and from the shift in the peak positions in XRD. Photoelectrochemical (PEC) solar cells are fabricated by using the as-grown single crystal samples along with iodine/iodide electrolytes. Mott–Schottky plots for different compositions of iodine/iodide electrolytes show that 0.025 M I₂+1 M NaI+2 M Na₂SO₄+0.5 M H₂SO₄ will be the most suitable electrolyte. Study of efficiency (η) and fill factor for different intensities of illuminations at room temperature is carried out for the five samples. The In-doped SnS single crystals show better PEC efficiency than the undoped and Sb-doped SnS single crystals.

The gate-induced-drain-leakage of MOSFETs is analyzed to better understand the sub-threshold swing degradation of SiGe tunnel field-effect transistors and their band-to-band tunneling mechanism. The numerical model of the analysis is elaborated. Equivalent trap energy levels are extracted for Si and strained SiGe. It is found that the equivalent trap energy level in SiGe is shallower than that in Si.

Composite materials based on plasmonic nanoparticles allow building metamaterials with very large effective permittivity (positive or negative). Moreover, if clustered or combined with other nanoparticles, it is also possible to generate effective magnetic permeability (positive or negative), and an ad-hoc design would result in the generation of double negative materials, and therefore backward wave propagation. In this work, the optical properties such as the effective permittivity, permeability and refractive index of Au-ZnS and Au-ZnO nanocomposites in a broad frequency range are studied. The enhancement is attributed to energy transfer from ZnS or ZnO to Au followed by a large local electromagnetic field on or near the surface of the Au nanoparticles. Local surface plasmon resonance could be the key reason for this enhancement. The surface plasmon, in response to changes in the refractive index of the local environment, also depends on the type of metal through the bulk plasma wavelength and the nano-particle compositions and geometry.

We perform a first-principles study of the mechanical and vibrational properties of ZnS with a wurtzite structure. The calculated elastic constants by using a pseudopotential plane-wave method agree well with the experimental data and with the previous theoretical works. Based on the elastic constants and their related parameters, the crystal mechanical stability is discussed. Calculations of the zone-center optical-mode frequencies including longitudinal-optical/transverse-optical splitting, by using the density functional perturbation theory, are reported. All optical modes are identified, especially B₁ modes, and agree with Raman measurements.

Researchers have reported that Cu-Zr liquids are kinetically strong at the best glass-forming compositions. Here we systematically study the temperature dependence of viscosity and diffusion of Cu-Zr liquids using molecular dynamics simulations, and the results illustrate that the better glass formers are actually more fragile close to the glass transition. There is a kinetic transition from low to high fragility when the optimal glass-forming liquids are quenched into glass states. This transition is associated with the more rapid decrease of the excess entropy of the liquids above and close to the glass transition temperature, T_g, compared to other compositions. Accompanied by the transition to high fragility, peaks in the thermal expansivity and specific heat are observed at the optimal compositions. Furthermore, the Stokes–Einstein relation is examined over a wide composition range for Cu-Zr alloys, and the results indicate that glass-forming ability closely correlates with dynamical heterogeneity.

A water strider's floating mechanism is of significance for the design of new biomimetic robots. However, the explanation of this mechanism has not been fully comprehended due to a lack of effective experimental methods. We describe a novel transmission speckle correlation technique, which is used to determine the deformation of liquid surfaces caused by a resting water strider, as well as a calculation of the resulting forces in the vertical direction. Furthermore, the variation of the liquid surface morphology at different times in the process of a water strider being unconscious has been measured and analyzed. The results show that the wax material secreted by water striders is a vital source for the excellent floating ability of a water strider, and that the effective time of the wax is less than 2 h.

The space charge distributions of cross-linked polyethylene (XLPE) with Borouge's Borlink^TM semiconductive screen type LE0550 and LE0595 from a pulsed electro-acoustic method are obtained. The contact interface morphology at the semiconductive screen and the structure of XLPE near the interface are characterized. The dielectric spectrum and the conductivity current of XLPE with the different semiconductive electrodes are compared. The semiconductive screen changes the structure and the dielectric characteristic of XLPE near the contact interface, which may be the main reason for space charge suppression in XLPE with Borouge's type LE0550 semiconductive screen.

Based on the non-equilibrium Green's function formalism and spin-polarized density functional theory calculations, we investigate the spin transport properties of HDI and terahydrotetraazahexacene diimide (4H-TAHDI) with two ferromagnetic zigzag-edge graphene nanoribbon electrodes. Compared with HDI, four carbon atoms in the hexacene part of 4H-TAHDI are substituted by nitrogen atoms. The results show that the nitrogen substitution can improve significantly the spin-filtering performance and 4H-TAHDI can be used as a perfect spin filter. Our study indicates that suitable chemical substitution is a possible way to realize high-efficiency spin filters.

The electroforming process of Ti/HfO_x stacked RRAM devices is removed via the combination of low temperature atomic layer deposition and post metal annealing. The Pt/Ti/HfO_x/Pt RRAM devices show a forming-free bipolar resistive switching behavior. By x-ray photoelectron emission spectroscopy analysis, it is found that there are many oxygen vacancies and nonlattice oxygen pre-existing in the HfO_x layer that play a key role in removing the electroforming process. In addition, when the thickness ratio of the Ti and HfO_x layer is 1, the uniformity of the switching parameters of Pt/Ti/HfO_x/Pt devices is significantly improved. The OFF/ON window maintains about 100 at the read voltage of 0.1 V.

To enhance the performance of nanoelectronics based on Au-ZnSe nanowire (NW)-Au (M-S-M) nanostructure, the effect of irradiation of the high energy electron beam emitted from the electron gun of a transmission electron microscope operated at 200 kV on the current carrying capability of M-S-M nanostructure is investigated in situ. Focusing the high energy electron beam on a Au electrode, the current carrying capability of the M-S-M nanostructure can be enhanced significantly with respect to the case of the electron beam being switched off. In this case, the electrons in the electrode are excited by the incident high energy electron and can freely tunnel through the Schottky barriers at the metal-semiconductor NW (M-S) nanocontacts, which can effectively reduce Joule heat dissipation and remarkably improve the current carrying capability of M-S-M nanostructure due to the fact that the current carrying capability highly depends on the Joule heating effect of Schottky barriers at M-S nanocontacts.

The electronic, magnetic, and ferroelectric properties of BiCrO₃ in C2/c and R3c structure are investigated by first principles calculations. It is found that the easy magnetization axis in C2/c structure is along the b axis, the magnetic order in R3c structure is G-type antiferromagnetic and the easy magnetization axis is along the rhombohedral [111] direction. Berry phase theory predicts that the R3c structure of BiCrO₃ has a large spontaneous polarization of 73.9 μC/cm² along the rhombohedral [111] direction.

A dual probe, i.e., high resolution scanning piezo-thermal microscopy, is developed and employed to characterize the local piezoresponse and thermal behaviors of ferroelastic domains in multiferroic BiFeO₃ thin films. Highly inhomogeneous piezoelectric responses are found in the thin film. A remarkably local thermal transformation across ferroelastic domain walls is clearly demonstrated by the quantitative 3Ω signals related to thermal conductivity. Different polarization oriented ferroelastic domains are found to exhibit different local thermal responses. The underlying mechanism is possibly associated with the inhomogeneous stress distribution across the ferroelastic domain walls, leading to different phonons scattering contributions in the BiFeO₃ thin film.

We present a design and realization of a high efficiency C-Band (5.2 GHz–5.8 GHz) internally-matched gallium nitride (GaN) power amplifier (PA). To reduce power dissipation and to achieve high efficiency, both input and output matching networks, along with 2nd-harmonic modulation circuits, are designed accurately according to the source and load optimum impedances extracted by source-pull and load-pull measurements. The PA realizes an excellent rf performance under a pulsed condition, demonstrating a maximum output power of 52.2 dBm (164 W) with at least 13.5 dB gain in the frequency range from 5.2 GHz to 5.8 GHz (10% relative bandwidth). At the same time, a power-added efficiency (PAE) of 69.4% is observed at 5.6 GHz and over 65.0% throughout the whole bandwidth. The PAE is the state-of-art performance for C-band GaN high-electron-mobility transistor PA with such high output power, to the best of our knowledge.

We investigate the effect of amorphous hydrogenated silicon (a-Si:H) films passivated on silicon surfaces based on high-pressure water-vapor annealing (HWA). The effective carrier lifetime of samples reaches the maximum value after 210°C, 90 min HWA. Capacitance-voltage measurement reveals that the HWA not only greatly reduces the density of interface states (D_it), but also decreases the fixed charges (Q_fixed) mainly caused by bulk defects. The change of hydrogen and oxygen in the film is measured by a spectroscopic ellipsometer and a Fourier-transform infrared (FTIR) spectrometer. All these results show that HWA is a useful method to improve the passivation effect of a-Si:H films deposited on silicon surfaces.

The optical property and injection efficiency of N-face AlGaN based ultraviolet light emitting diodes (UV-LEDs) are studied and compared with Ga-face AlGaN based UV-LEDs. A staircase electron injector is introduced in the N-face AlGaN based UV-LED. The electroluminescence spectra, power-current performance curves, energy band diagrams, carrier concentration and radiative recombination rate are numerically calculated. The results indicate that the N-face UV-LED has a better optical performance than the Ga-face UV-LED, and the injection efficiency is enhanced owing to the fact that the staircase electron injector is available for UV-LEDs.

The effect of Be doping on the quantum efficiency and the dark current of InAs/GaSb long-wavelength infrared superlattice photodetectors grown by molecular-beam epitaxy on GaSb substrates are reported. A significant improvement of quantum efficiency (QE) with p-type doping is demonstrated. Our results show that Be doping level at 2.5×10¹⁵ cm³ gives the highest quantum efficiency of product 28%. We also demonstrate that the increased QE is not only resulted from the longer minority carrier diffusion length, but also the p-n junction location change. Finally, the result also shows that the sample with a doping density of 2.5×10¹⁵ cm³ has the largest D^* as 8.68×10¹⁰ cm?Hz^1/2?W^?1, which is almost five times D^* of the non-intentionally doped one.

We propose a novel nonvolatile threshold adaptive transistor (TAT) for neuromorphic circuits. The threshold adaptive transistor is achieved by embedding a resistive random-access memory (RRAM) material stack between the gate electrode and gate dielectric. During operation, the embedded RRAM device is kept at a high resistance state, which makes it act as a nonvolatile capacitor. The threshold could be nonlinearly adjusted by the voltage pulses applied on the gate of the transistor. We quantitatively estimate the range of the capacitance variation of the RRAM device. The threshold voltage of the TAT is simulated and shows expected variation. The simulated output of an inverter using a TAT shows a nonlinear adaptive behavior.

Nanogranular Al₂O₃ films deposited by plasma-enhanced chemical vapor deposition show a high proton conductivity of ～1.25 × 10^?4 S/cm and a huge electric-double-layer (EDL) capacitance of ～4.8 μF/cm² at room temperature. Using nanogranular Al₂O₃ proton conducting films as gate dielectrics, junctionless indium-zinc-oxide (IZO) thin-film transistors (TFTs) with a coplanar-gate configuration are fabricated. The unique feature of such junctionless TFTs is that the channel and source/drain electrodes are the same thin IZO film without any source/drain junction. Due to the strong EDL capacitive coupling triggered by mobile protons in nanogranular Al₂O₃, these TFTs show a low-voltage operation of 1.5 V and a high performance with a large field-effect mobility (>18 cm²/V?s), a small subthreshold swing (<130 mV/decade) and a high current on/off ratio (>10⁶). Our results demonstrate that such junctionless TFTs gated by Al₂O₃ proton conducting films have great potential applications in low-power and low-cost electronics.