Potential energy curves of six electronic states (X1Σ+, a3Σ+, A1Σ+, b3Π, B1Π, c3Σ+) corresponding to the first dissociation limit Be+(2S)+X(2S) and the second dissociation limit Be+ (2P)+X(2S) of BeX+ (X=H,D,T) are calculated using the internally contracted multiconfiguration-reference configuration interaction approach based on the consistent cc-pVQZ basis set. Based on the calculated potential energy curves, one-dimensional radial Schrdinger equations are solved by using LEVEL program. Consequently, the ro-vibrational constants, Franck-Condon factors and radiative lifetimes of the corresponding electronic states are obtained. The spin-orbital coupling constants of b3Π and c3Σ+ states are respectively evaluated on the basis of the calculation of Breit-Pauli operator. The Boltzmann population distribution of A1Σ+ state of BeH+ are derived at vibrational temperatures of 2500, 5000, 7500, 10000 K. Moreover, the spectra of Δν=-2 and Δν=-3 bands in A1Σ+-X1Σ+ system at the rotational temperatures of 500, 1000, 1500, 2000 K are simulated respectively when the vibrational temperature is 10000 K.

In order to prevent the negative effect of vibration of vehicle-mounted Fourier transform infrared (FTIR) spectrometer produced in the process of movement on the FTIR spectrometer, and ensure signal-to-noise rate and measurement accuracy of the spectrometer, a FTIR spectrometer system combining a structure of angle mirror and a damping system with single degree of freedom is designed to increase the anti-vibration performance of the spectrometer. A series of test experiments about desktop vibration are conducted to validate the good anti-vibration performance of swing angle mirror structure, which proves that damping system of single degree of freedom could significantly increase the anti-vibration performance of spectrometer. Finally, experiments on vehicle-mounted FTIR spectrometer are carried out. Results show that the mean signal-to-noise rate of the spectrum measured in the process of movement reached 94% of that in the static process. The designed system can run smoothly in mobile platform, which has good anti-vibration performance and can provide application conditions for vehicle-mounted monitoring of FTIR spectrometer.

For the advantage of simple structure and good anti-aliasing, cascaded integrator comb (CIC) filter has been widely used in a variety of signal processing systems. Aiming at the problem of large passband distortion and small stopband attenuation of the traditional CIC filter, a Chebyshev cascade integral comb (C-CIC) filter is proposed by analyzing the characteristics of CIC filter. The simulation results using MatLab show that compared with the traditional CIC, interpolated second-order polynomial cascade integral comb filter (ISOP-CIC) and cosine integral comb filter (CIC-COSINE), the C-CIC filter has a large improvement in passband distortion at frequency fc and stopband attenuation at frequency fa when the number of CIC cascades is the same. According to the Quartus simulation, design tool of FPGA, the C-CIC filter consumes less on-chip resources than the ISOP-CIC and CIC-COSINE filters when the same amplitude-frequency characteristics are achieved. It is indicated that the C-CIC filter can be better used in tunable diode laser absorption spectrometer (TDLAS) system.

When it is applied to quantum image stitching, the traditional scale-invariant feature transform (SIFT) algorithm will result in the problems such as unreasonable feature point distribution and high mismatch rate. So an improved SIFT quantum image stitching algorithm based on dynamic threshold and global information is proposed. In the aspect of unreasonable feature point number, as the number is proportional to the number of quantum dots or quantum rings, the contrast threshold of SIFT algorithm is set by calculating the density of quantum dots or rings so as to get the appropriate feature point number. In the aspect of reducing high false mismatch rate, a global information descriptor is constructed and combined with the local SIFT descriptor. The experimental results show that the improved algorithm can effectively complete the stitching of quantum rings, quantum wire and quantum dot images, effectively control the feature points of quantum images within a reasonable range, and reduce the mismatch rate from 17.34%～33.02% to 10.84%～20%, which makes the quantum image stitching have better reliability.

Micromechanical resonator is widely used in accurate measurements, in which frequency modulation and amplitude modulation are two usually used techniques. Generally, the force sensitivity of mechanical resonator is mainly limited by the thermal noise. Therefore, reducing the thermal noise of measurement quadrature by squeezing the mechanical resonator can effectively improve the sensitivity of the mechanical resonator. By using a phase lock loop to lock the resonator’s vibration frequency, a specified motion quadrature of mechanical resonator is squeezed when the frequency of the mechanical resonator is modulated at twice of its resonant frequency by using an optical trap. By using a feedback loop to stabilize the measurement system, 3 dB limit of the parametric squeezing is successfully overcome and a max squeezing rate about 4.4 dB is achieved.

A genuine seven-qubit entangled state is presented as channel of quantum teleportation, and based on which, two new schemes of bidirectional controlled quantum teleportation are proposed. One scheme is that with the control of Charlie, Alice teleportates an unknown qubit to Bob and Bob teleportates an unknown two-qubit to Alice in the same time. The other scheme is that with the control of Charlie, Alice teleportates an unknown two-qubit with the form of Schmidt decomposition to Bob and Bob transmits an arbitrary unknown two-qubit to Alice simultaneously. In the proposed schemes, the agents measure their particles with the base Bell or GHZ and transmit the results to each other through classical channel. Then, the supervisor measures his particle with X base and transmits the result to the agents by classical communication. Finally, the agents can restore the quantum state teleported by the sender through applying unitary operators on his particles. Compared with the existed schemes, the intrinsic efficiency of proposed schemes is higher. Moreover, the genuine entangled seven-qubit state used can be produced through some simple quantum unitary gates.

In the hybrid quantum-classical networks, how the quantum signal wavelength and classical signal wavelength are distributed determines the degree to which the quantum key distribution (QKD) performance is affected by the classical optical signal noise. Aiming at the wavelength assignment optimization scheme based on the principle that the noise is minimal, the optimization degree of QKD performance is investigated. The effects of wavelength interval and channel number on the performance of QKD are analyzed. Simulation results show that the optimization scheme can improve the key generation rate and the furthest secure transmission distance of the networks. With a given number of quantum and classical channels, the quantum key generation rate and the furthest secure transmission distance of the networks decrease with the increase of the wavelength interval. When the number of classical channels and wavelength intervals is fixed, the total key generation rate of the networks increases with the increase of quantum channel number, while the average key generation rate and the furthest secure transmission distance of each quantum channel both decrease.

A hybrid bidirectional controlled quantum communication protocol for arbitrary two-qubit states is proposed by using a nine-qubit entangled state as quantum channel. In this protocol, two distant parties, Alice and Bob, are not only senders but also receivers. Alice can teleport an unknown arbitrary two-qubit state to Bob, and at the same time, Bob can also help Alice prepare an arbitrary two-qubit state remotely. This protocol shows that only when the sender and the controller collaborate with each other, the quantum task can be completed successfully, and the total success probability of this protocol is 100%.

In the real quantum key distribution (QKD) system, statistical fluctuation of the source parameters will happen with the changes of time and environment, which will lead to a serve decrease of the key rate. Regarding to the problem, a method is proposed to eliminate the influence of statistical fluctuation of the source parameters on the performance of QKD. In the method, the heralded coherent sources are used to replace the widely used weak coherent sources, which can significantly improve the key rate of QKD when there is statistical fluctuation on the source parameters, and thus the influence of statistical fluctuation on the source parameters is eliminated, while the maximum transmission distance is also significantly improved. Both the theoretical analysis and numerical simulation verify the feasibility of the proposed method, and it is believed that the method can provide a new idea for the practical application of QKD.

A scheme that Λ-type three-level atoms are used to entangle movable mirror and cavity field in a Fabry-Perot cavity is proposed. The mechanism that the stable entanglement of optomechanical system can be generated through radiation pressure is presented. It is shown that the larger stationary entanglement can be obtained with the existence of atomic mediums. The criterion of Simon is employed in the proposed scheme to determine the entanglement, and the logarithmic negativity is used to quantify the stable macroscopic entanglement of the system. It is found that the larger entanglement corresponds to the larger coupling between the cavity and the atoms. With the help of atoms, the maximum entanglement of the system increases from 0.5 to 2.05. And such macroscopic entanglement still exists even for bad cavity limits.

Regarding the decoherence phenomena caused by some factors of external environment in an open quantum system, a quantum prisoner dilemma game model is established under amplitude channels by using EWL quantization scheme based on quantum game theory. The payoffs and Nash equilibrium solutions are obtained both in memoryless and complete memory channels, and the influence of noise strength on Nash equilibrium is also analyzed. It is found that noise has no effect on Nash equilibrium when the noise strength is less than 0.5961 under the memoryless amplitude damping channel, while the threshold value increases to 0.9654 under the complete memory condition. It indicates that the Nash equilibrium under the complete memory tends to be more stable and less susceptible to the influence of external environment than that under the memoryless condition, which provides a certain reference for decision-making of a feasible solution to the prisoner’s dilemma in the open quantum system.

The energy spectrum and second-order coherence degree of a cascade three-level atom interacting with a single mode binomial state field are calculated accurately in the non-rotating wave approximation. The level-crossing problem is discussed by using fidelity. The influences of the binomial state field parameter η and superposition of atomic energy levels at the initial time on the second-order coherence degree are studied. Results indicate that the duration of the bunching effect decreases gradually with the increase of light field parameter η. The duration of the light field antibunching effect decreases due to the superposition of atomic energy levels. Whether the atom is in superposition state or not at the beginning time, the light field displays antibunching effect completely when the value of η is big enough. Because of the virtual photon effect induced by non-rotating wave approximation, the little indentation oscillation appears in the second-order coherence degree evolution curves.

Non-line-of-sight ultraviolet communication can be competent for complex environment and special terrain. However, atmospheric absorption, scattering and turbulence can result in rapid attenuation of signal intensity, which greatly limits the transmission distance. Cooperative relay is an effective method to overcome this shortcoming and expand the communication range. For the non-coplanar relay assisted ultraviolet scattering system in atmospheric turbulence, the closed-form expressions of outage probability under decode-and-forward (DF) protocol as well as amplify-and-forward (AF) protocol are derived. The correctness of the theoretical analysis results is verified through Monte Carlo simulation. The simulation results show that the outage performance of DF is better than that of AF. And the higher the optical transmission power, the smaller the receiving elevation and the offset angle, the better the outage performance of the system. Moreover, the change rule of outage probability with transmission elevation is different when the offset angle is different.

The influence of the phonon dispersion on the weak coupling polaron in monolayer graphene is investigated by using the linear combination operator and LLP unitary transformation method and taking account of the longitudinal optical (LO) phonons dispersion. The ground state energy and the zero-Landau level splitting energy in monolayer graphene as a function of the coefficient of the phonon dispersion are obtained in a parabolic dispersion approximation. Numerical calculation results show that the ground state energy increases with the increasing of Debye cut-off wave number, and the zero-Landau level splitting energy decreases with the increasing of phonon dispersion coefficient.

Due to its narrow band gap and low toxicity, the lead-tin perovskite material has been widely used in fabricating perovskite solar cells. However, the poor film forming quality of lead-tin perovskite limits the improvement of battery efficiency. By adding dimethyl sulfoxide into the precursor solution to decrease the crystallization speed, a dense pinhole-free perovskite film is fabricated. Moreover, tin fluoride and fullerene derivatives are added to reduce defects in the perovskite lattice, grain boundaries and surface, which leads to the high device efficiency. The efficiency of the half lead tin perovskite solar cell prepared in this work is up to 15.1%.

The electron spin conductance switch effect in a two step-likes quantum wire under the modulation of both the Rashba and Dresselhaus spin-orbit couplings (SOCs) is investigated by using the non-equilibrium Green’s function (NEGF) method with tight binding approximation scheme. Results show that a very large spin conductance occurs in the system under consideration when the electrons transport in the forward biased case, while the spin conductance vanishes when the electrons transport in the backward biased case. Moreover, it is found that the spin conductance of the system displays a“circular”profile according to the change of both the Rashba and Dresselhaus SOCs, which demonstrates that the two SOCs have the same effects on inducing spin conductance. Therefore, one can control the spin conductance of the system by tuning either the Rashba or Dresselhaus SOC strength, which indicates that the system can be utilized to make the proposed quantum wire with all-electrical spin conductance diode in the future.

Surface plasmon polaritons (SPPs) propagating on metal surfaces corrugated with periodic grooves are investigated in the mid-far infrared band. Results show that the structured surface can significantly reduce the asymptotic frequency and improve the field confinement of SPPs propagating on it. The influence of the metal absorption loss on the performance of spoof SPPs (SSPPs) is also studied at the same frequency range. It is shown that sub-wavelength field confinement and long-distance propagation can be obtained simultaneously for SSPPs on metal surface corrugated with periodic grooves. The guiding ability of SSPPs supported by the structured surface is further verified by simulating the transmission of electromagnetic waves along it. The proposed surface structure may lead to the design and development of new integrated guided wave devices in mid-far infrared band.