查看更多>>摘要：Leveraging the extraordinary phenomena of quantum superposition and quantum correlation,quantum computing offers unprecedented potential for addressing challenges beyond the reach of classical computers.This paper tackles two pivotal challenges in the realm of quantum computing:firstly,the development of an effective encoding protocol for translating classical data into quantum states,a critical step for any quantum computation.Different encoding strategies can significantly influence quantum computer performance.Secondly,we address the need to counteract the inevitable noise that can hinder quantum acceleration.Our primary contribution is the introduction of a novel variational data encoding method,grounded in quantum regression algorithm models.By adapting the learning concept from machine learning,we render data encoding a learnable process.This allowed us to study the role of quantum correlation in data encoding.Through numerical simulations of various regression tasks,we demonstrate the efficacy of our variational data encoding,particularly post-learning from instructional data.Moreover,we delve into the role of quantum correlation in enhancing task performance,especially in noisy environments.Our findings underscore the critical role of quantum correlation in not only bolstering performance but also in mitigating noise interference,thus advancing the frontier of quantum computing.
查看更多>>摘要：Entanglement in macroscopic systems,as a fundamental quantum resource,has been utilized to propel the advance-ment of quantum technology and probe the boundary between the quantum and classical realms.This study focuses on a unique hybrid quantum system comprising of an ensemble of silicon vacancy(SiV)centers coupled to phononic waveg-uides in diamond via strain interactions.By employing two sets of time-dependent,non-overlapping driving fields,we investigate the generation process and dynamic properties of macroscopic quantum entanglement,providing fresh insights into the behavior of such hybrid quantum systems.Furthermore,it paves the way for new possibilities in utilizing quantum entanglement as an information carrier in quantum information processing and quantum communication.
查看更多>>摘要：We investigate a periodically driven Haldane model subjected to a two-stage driving scheme in the form of a step function.By using the Floquet theory,we obtain the topological phase diagram of the system.We also find that anomalous Floquet topological phases exist in the system.Focusing on examining the quench dynamics among topological phases,we analyze the site distribution of the 0-mode and π-mode edge states in long-period evolution after a quench.The results demonstrate that,under certain conditions,the site distribution of the 0-mode can be confined at the edge even in long-period evolution.Additionally,both the 0-mode and π-mode can recover and become confined at the edge in long-period evolution when the post-quench parameters(T,M2/M1)in the phase diagram cross away from the phase boundary M2/M1=6√3t2/M1-1.Furthermore,we conclude that whether the edge state is confined at the edge in the long-period evolution after a quench depends on the similarity of the edge states before and after the quench.Our findings reveal some new characteristics of quench dynamics in a periodically driven system.
查看更多>>摘要：This paper presents a comprehensive framework for analyzing phase transitions in collective models such as the Vicsek model under various noise types.The Vicsek model,focusing on understanding the collective behaviors of social animals,is known due to its discontinuous phase transitions under vector noise.However,its behavior under scalar noise remains less conclusive.Renowned for its efficacy in the analysis of complex systems under both equilibrium and non-equilibrium states,the eigen microstate method is employed here for a quantitative examination of the phase transitions in the Vicsek model under both vector and scalar noises.The study finds that the Vicsek model exhibits discontinuous phase transitions regardless of noise type.Furthermore,the dichotomy method is utilized to identify the critical points for these phase transitions.A significant finding is the observed increase in the critical point for discontinuous phase transitions with escalation of population density.
查看更多>>摘要：The distribution of continuous service time in call centers is investigated.A non-Maxwellian collision kernel com-bining two different value functions in the interaction rule are used to describe the evolution of continuous service time,respectively.Using the statistical mechanical and asymptotic limit methods,Fokker-Planck equations are derived from the corresponding Boltzmann-type equations with non-Maxwellian collision kernels.The steady-state solutions of the Fokker-Planck equation are obtained in exact form.Numerical experiments are provided to support our results under different parameters.
查看更多>>摘要：The composite time scale(CTS)provides a stable,accurate,and reliable time scale for modern society.The im-provement of CTS's real-time performance will improve its stability,which strengths related applications'performance.Aiming at this goal,a method achieved by determining the optimal calculation interval and accelerating adjustment stage is proposed in this paper.The determinants of the CTS's calculation interval(characteristics of the clock ensemble,the measurement noise,the time and frequency synchronization system's noise and the auxiliary output generator noise floor)are studied and the optimal calculation interval is obtained.We also investigate the effect of ensemble algorithm's initial parameters on the CTS's adjustment stage.A strategy to get the reasonable initial parameters of ensemble algorithm is designed.The results show that the adjustment stage can be finished rapidly or even can be shorten to zero with reasonable initial parameters.On this basis,we experimentally generate a distributed CTS with a calculation interval of 500 s and its stability outperforms those of the member clocks when the averaging time is longer than～1700 s.The experimental result proves that the CTS's real-time performance is significantly improved.
查看更多>>摘要：An optical-tweezers-based dual-frequency-band particle tracking system was designed and fabricated for liquid vis-cosity detection.On the basis of the liquid viscosity dependent model of the particle's restricted Brownian motion with the Faxén correction taken into account,the liquid viscosity and optical trap stiffness were determined by fitting the theoretical prediction with the measured power spectral densities of the particle's displacement and velocity that were derived from the dual-frequency-band particle tracking data.When the SiO2 beads were employed as probe particles in the measurements of different kinds of liquids,the measurement results exhibit a good agreement with the reported results,as well as a detection uncertainty better than 4.6％.This kind of noninvasive economical technique can be applied in diverse environments for both in situ and ex situ viscosity detection of liquids.
查看更多>>摘要：By numerically solving the semiconductor Bloch equation(SBEs),we theoretically study the high-harmonic genera-tion of ZnO crystals driven by one-color and two-color intense laser pulses.The results show the enhancement of harmonics and the cut-off remains the same in the two-color field,which can be explained by the recollision trajectories and electron excitation from multi-channels.Based on the quantum path analysis,we investigate contribution of different ranges of the crystal momentum k of ZnO to the harmonic yield,and find that in two-color laser fields,the intensity of the harmonic yield of different ranges from the crystal momentum makes a big difference and the harmonic intensity is depressed from all k channels,which is related to the interferences between harmonics from symmetric k channels.
查看更多>>摘要：A Wigner-distribution-like(WDL)function based on the strong-field approximation(SFA)theory is used to investi-gate the ionization time of the photoelectron emitted from the initial states with different magnetic quantum number m in elliptically polarized electric fields.The saddle-point method is adopted for comparisons.For different m states,a discrep-ancy exists in the WDL distributions of the photoelectrons emitted in a direction close to the major axis of the laser field ellipse.Based on the saddle-point analysis,this discrepancy can be ascribed to the interference between electrons ionized from two tunneling instants.Our results show that the relationships between the tunneling instants and kinetic energy of photoelectrons are the same for different m initial states when the Coulomb potential is not considered.Our work sheds some light on the ionization-time information of electrons from different magnetic quantum states.
查看更多>>摘要：Using the operator correspondence of the real and fictious modes in the thermo entangled state representation,we solve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum representation of its analytical solution.we find that the pure coherent states evolve into the new mixed thermal superposed states in the diffusion channel.Also,we investigate the statistical properties of the initial coherent states and their entropy evolutions in the diffusion channel,and find that the entropy evolutions are only related to the decay time and without the amplitudes of the initial coherent states.
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