Catálogo de publicaciones - revistas

<jats:p>As a branch of quantum secure multiparty computation, quantum private comparison is applied frequently in many fields, such as secret elections, private voting, and identification. A quantum private comparison protocol with higher efficiency and easier implementation is proposed in this paper. The private secrets are encoded as single polarized photons and then encrypted with a homomorphic rotational encryption method. Relying on this method and the circular transmission mode, we implement the multiplexing of photons, raising the efficiency of our protocol to 100%. Our protocol is easy to realize since only single photons, unitary operation, and single-particle measurement are introduced. Meanwhile, the analysis shows that our protocol is also correct and secure.</jats:p>

<jats:p>The nonlinear dynamical exact wave solutions to the non-fractional order and the time-fractional order of the biological population models are achieved for the first time in the framwork of the Paul–Painlevé approach method (PPAM). When the variables appearing in the exact solutions take specific values, the solitary wave solutions will be easily obtained. The realized results prove the efficiency of this technique.</jats:p>

<jats:p>The study of the panic evacuation process is of great significance to emergency management. Panic not only causes negative emotions such as irritability and anxiety, but also affects the pedestrians decision-making process, thereby inducing the abnormal crowd behavior. Prompted by the epidemiological SIR model, an extended floor field cellular automaton model was proposed to investigate the pedestrian dynamics under the threat of hazard resulting from the panic contagion. In the model, the conception of panic transmission status (PTS) was put forward to describe pedestrians’ behavior who could transmit panic emotions to others. The model also indicated the pedestrian movement was governed by the static and hazard threat floor field. Then rules that panic could influence decision-making process were set up based on the floor field theory. The simulation results show that the stronger the pedestrian panic, the more sensitive pedestrians are to hazards, and the less able to rationally find safe exits. However, when the crowd density is high, the panic contagion has a less impact on the evacuation process of pedestrians. It is also found that when the hazard position is closer to the exit, the panic will propagate for a longer time and have a greater impact on the evacuation. The results also suggest that as the extent of pedestrian’s familiarity with the environment increases, pedestrians spend less time to escape from the room and are less sensitive to the hazard. In addition, it is essential to point out that, compared with the impact of panic contagion, the pedestrian’s familiarity with environment has a more significant influence on the evacuation.</jats:p>

<jats:p>The exploration of the memristor model in the discrete domain is a fascinating hotspot. The electromagnetic induction on neurons has also begun to be simulated by some discrete memristors. However, most of the current investigations are based on the integer-order discrete memristor, and there are relatively few studies on the form of fractional order. In this paper, a new fractional-order discrete memristor model with prominent nonlinearity is constructed based on the Caputo fractional-order difference operator. Furthermore, the dynamical behaviors of the Rulkov neuron under electromagnetic radiation are simulated by introducing the proposed discrete memristor. The integer-order and fractional-order peculiarities of the system are analyzed through the bifurcation graph, the Lyapunov exponential spectrum, and the iterative graph. The results demonstrate that the fractional-order system has more abundant dynamics than the integer one, such as hyper-chaos, multi-stable and transient chaos. In addition, the complexity of the system in the fractional form is evaluated by the means of the spectral entropy complexity algorithm and consequences show that it is affected by the order of the fractional system. The feature of fractional difference lays the foundation for further research and application of the discrete memristor and the neuron map in the future.</jats:p>

<jats:p>Dynamical behaviors of a class-B laser system with dissipative strength are analyzed for a model in which the polarization is adiabatically eliminated. The results show that the injected signal has an important effect on the dynamical behaviors of the system. When the injected signal is zero, the dissipative term of the class-B laser system is balanced with external interference, and the quasi-periodic flows with conservative phase volume appear. And when the injected signal is not zero, the stable state in the system is broken, and the attractors (period, quasi-period, and chaos) with contractive phase volume are generated. The numerical simulation finds that the system has not only one attractor, but also coexisting phenomena (period and period, period and quasi-period) in special cases. When the injected signal passes the critical value, the class-B laser system has a fold-Hopf bifurcation and exists torus “blow-up” phenomenon, which will be proved by theoretical analysis and numerical simulation.</jats:p>

<jats:p>Owing to the influence of sampling loss, cavity difference and detecting source, the multi-optical parameter measurement of atmospheric aerosol cannot be detected simultaneously in the same reference environment. In order to solve this problem, a new method of simultaneously detecting the aerosol optical parameters by coupling cavity ring-down spectrometer with photoacoustic spectroscopy is proposed. Firstly, the coupled photoacoustic cavity is formed by the organic fusion of the photoacoustic cavity and the ring-down cavity. Secondly, the integrated design of the coupling spectroscopy system is carried out. Finally, the extinction coefficient and absorption coefficient of aerosol are measured simultaneously by the system, and then the aerosol scattering coefficient and single albedo are calculated indirectly. The accuracy of the system is verified by comparing with the data from the environmental quality monitoring station, which provides a new idea for the detection of multi-optical characteristics of atmospheric aerosol.</jats:p>

<jats:p>Enhancing the upconversion luminescence of rare earth ions is crucial for their applications in the laser sources, fiber optic communications, color displays, biolabeling, and biomedical sensors. In this paper, we theoretically study the resonance-mediated (1 + 2)-three-photon absorption in Pr<jats:sup>3+</jats:sup> ions by a rectangle phase modulation. The results show that the resonance-mediated (1 + 2)-three-photon absorption can be effectively enhanced by properly designing the depth and width of the rectangle phase modulation, which can be attributed to the constructive interference between on-resonant and near-resonant three-photon excitation pathways. Further, the enhancement efficiency of resonance-mediated (1 + 2)-three-photon absorption can be affected by the pulse width (or spectral bandwidth) of femtosecond laser field, final state transition frequency, and absorption bandwidths. This research can provide a clear physical picture for understanding and controlling the multi-photon absorption in rare-earth ions, and also can provide theoretical guidance for improving the up-conversion luminescence.</jats:p>

<jats:p>The strong-field ionization of dimers is investigated theoretically in counter-rotating circularly polarized laser fields. By numerically solving the two-dimensional (2D) time-dependent Schrödinger equation (TDSE) with the single-electron approximation (SEA) frame, we present the photoelectron momentum distributions (PMDs) and photoelectron angular distribution (PADs) of aligned Ne and Xe dimers. It is found that the PMDs and PADs strongly depend on the time delays by counter-rotating circularly polarized laser pulses. The results can be explained by the ultrafast photoionization model and the evolution of electron wave packets for Ne and Xe dimers. Besides, We make a comparison of PMDs between Ne atom and Ne dimer.</jats:p>

<jats:p>The atomic selective multi-step photoionization process is a critical step in laser isotope separation. In this work, we study three-step photoionization processes with non-monochromatic laser fields theoretically based on the semi-classical theory. Firstly, three bandwidth models, including the chaotic field model, de-correlation model, and phase diffusion model, are introduced into the density matrix equations. The numerical results are compared with each other comprehensively. The phase diffusion model is selected for further simulations in terms of the correspondence degree to physical practice. Subsequently, numerical calculations are carried out to identify the influences of systematic parameters, including laser parameters (Rabi frequency, bandwidth, relative time delay, frequency detuning) and atomic Doppler broadening, on photoionization processes. In order to determine the optimal match among different systematic parameters, the ionization yield of resonant isotope, and selectivity factor are adopted as evaluation indexes to guide the design and optimization process. The results in this work can provide a rewarding reference for laser isotope separation.</jats:p>

<jats:p>The <jats:italic>L</jats:italic>-shell x-ray of Nd has been obtained for 300–600 keV He<jats:sup>2+</jats:sup> ions impacting, and compared with that produced by H<jats:sup>+</jats:sup> and <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{H}}}_{2}^{+}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi mathvariant="normal">H</mml:mi> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_31_6_063204_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> ions. The threshold of projectile kinetic energy for <jats:italic>L</jats:italic>-shell ionization of Nd is crudely verified in the energy region of about 300–400 keV. It is found that the energy of the distinct <jats:italic>L</jats:italic>-subshell x-rays has a blue shift. The relative intensity ratios of <jats:italic>Lβ</jats:italic> <jats:sub>1, 3, 4</jats:sub> and <jats:italic>Lβ</jats:italic> <jats:sub>2, 15</jats:sub> to <jats:italic>Lα</jats:italic> <jats:sub>1, 2</jats:sub> x-ray are enlarged compared to the atomic data, and they decrease with the increase of the incident energy, and increase with increasing the effective nuclear charge of the incident ions. That is interpreted by the multiple ionization of outer-shells induced by light ions.</jats:p>