查看更多>>摘要：This paper aims to propose a fourth-order matrix spectral problem involving four potentials and generate an associated Liouville integrable hierarchy via the zero curvature formulation.A bi-Hamiltonian formulation is furnished by applying the trace identity and a recursion operator is explicitly worked out,which exhibits the Liouville integrability of each model in the resulting hierarchy.Two specific examples,consisting of novel generalized combined nonlinear Schrödinger equations and modified Korteweg-de Vries equations,are given.
查看更多>>摘要：The rapid development of the Internet has accelerated the spread of rumors,posing challenges to social cohesion and stability.To address this,a multi-channel rumor propagation model incorporating individual game behavior and time delay is proposed.It depicts individuals strategically choosing propagation channels in the rumor spread process,capturing real-world intricacies more faithfully.Specifically,the model allowing spreaders to choose between text and video information base channels.Strategy adoption hinges on benefits versus costs,with payoffs dictating strategy and the propagation process determining an individual's state.By theoretical analysis of the model,the propagation threshold and equilibrium points are obtained.Then the stability of the model is further demonstrated based on Routh-Hurwitz judgment and Descartes'Rule of Signs.Numerical simulations are conducted to verify the correctness of the theoretical results and the sensitivity of the model to key parameters.The outcomes reveal that increasing the propagation cost of spreaders can significantly curb the spread of rumors.In contrast to the classical ISR model,rumors spread faster and more widely in the improved multi-channel rumor propagation model in this paper,which is a feature more aligned with real-world scenarios.Finally,the validity and predictive ability of the model are verified by using real rumor propagation data sets,indicating that the improved multi-channel rumor propagation model has good practical application and predictive value.
查看更多>>摘要：We investigate the non-Gaussian feature of radiation in a circuit quantum electrodynamics(QED)system where two qubits are strongly coupled to a single-mode cavity.In the regime of ultrastrong coupling(USC),the rotating-wave approximation is not valid,and the Rabi Hamiltonian contains counter-rotating wave terms,leading to level crossing and avoided crossings in the energy spectrum.We further analyze the intensity-amplitude correlation of the output field in these two novel scenarios.In the USC regime,the creation and annihilation operators in the correlation function are replaced,allowing for the identification of non-Gaussian features in the output field.Our findings reveal that despite the absence of squeezing effects in the output light,significant non-Gaussian characteristics are present.Additionally,we demonstrate that as the driving or coupling strength increases,the non-Gaussian features of the output field become more pronounced.This suggests that USC systems hold broad potential applications in the realms of nonlinear optics and the generation of non-Gaussian states.
查看更多>>摘要：We consider generating maximally entangled states(Bell states)between two qubits coupled to a common bosonic mode,based on f-STIRAP.Utilizing the systematic approach developed by Wang et al(2017 New J.Phys.19 093016),we quantify the effects of non-adiabatic leakage and system dissipation on the entanglement generation,and optimize the entanglement by balancing non-adiabatic leakage and system dissipation.We find the analytical expressions of the optimal coupling profile,the operation time,and the maximal entanglement.Our findings have broad applications in quantum state engineering,especially in solid-state devices where dissipative effects cannot be neglected.
查看更多>>摘要：It is well known that nonlocal coherence reflects nonclassical correlations better than quantum entanglement.Here,we analyze nonlocal coherence harvesting from the quantum vacuum to particle detectors adiabatically interacting with a quantum scalar field in Minkowski spacetime.We find that the harvesting-achievable separation range of nonlocal coherence is larger than that of quantum entanglement.As the energy gap grows sufficiently large,the detectors harvest less quantum coherence,while the detectors could extract more quantum entanglement from the vacuum state.Compared with the linear configuration and the scalene configuration,we should choose the model of equilateral triangle configuration to harvest tripartite coherence from the vacuum.Finally,we find a monogamous relationship,which means that tripartite l1-norm of coherence is essentially bipartite types.
查看更多>>摘要：Quantifying entanglement measures for quantum states with unknown density matrices is a challenging task.Machine learning offers a new perspective to address this problem.By training machine learning models using experimentally measurable data,we can predict the target entanglement measures.In this study,we compare various machine learning models and find that the linear regression and stack models perform better than others.We investigate the model's impact on quantum states across different dimensions and find that higher-dimensional quantum states yield better results.Additionally,we investigate which measurable data has better predictive power for target entanglement measures.Using correlation analysis and principal component analysis,we demonstrate that quantum moments exhibit a stronger correlation with coherent information among these data features.
查看更多>>摘要：Classical machine learning algorithms seem to be totally incapable of processing tremendous data,while quantum machine learning algorithms could deal with big data unhurriedly and provide exponential acceleration over classical counterparts.In this paper,we propose two quantum support vector machine algorithms for multi classification.One is the quantum version of the directed acyclic graph support vector machine.The other one is to use the Grover search algorithm before measurement,which amplifies the amplitude of the phase storing of the classification result.For k classification,the former provides quadratic reduction in computational complexity when classifying.The latter accelerates the training speed significantly and more importantly,the classification result can be read out with a probability of at least 50％using only one measurement.We conduct numerical simulations on two algorithms,and their classification success rates are 96％and 88.7％,respectively.
查看更多>>摘要：Effects of a Bohmian type quantum-relativistic theory are explored.The model is obtained by introducing a new and independent time parameter whose relative motions are not directly observable and cause quantum uncertainties of the physical observables.Unlike the usual de Broglie-Bohm theories,the Quantum Potential does not directly affect the observable motion,but determines the one that is relative to the new time variable.It turns out that the Zitterbewegung of a free particle,of which a more general law is obtained,is the key example of these hidden motions and,through it,it seems possible to give physical reality to the Feynman's paths.A relativistic revision of the uncertainty principle is also derived from the theory.
查看更多>>摘要：The Hubble tension persists as a challenge in cosmology.Even early dark energy(EDE)models,initially considered the most promising for alleviating the Hubble tension,fall short of addressing the issue without exacerbating other tensions,such as the S8 tension.Considering that a negative dark matter(DM)equation of state(EoS)parameter is conducive to reduce the value of the σ8 parameter,we extend the axion-like EDE model in this paper by replacing the cold dark matter(CDM)with DM characterized by a constant EoS wdm(referred to as WDM hereafter).We then impose constraints on this axion-like EDE extension model,along with three other models:the axion-like EDE model,AWDM,and ACDM.These constraints are derived from a comprehensive analysis incorporating data from the Planck 2018 cosmic microwave background,baryon acoustic oscillations,and the Pantheon compilation,as well as a prior on H0(i.e.H0=73.04±1.04,based on the latest local measurement by Riess et al)and a Gaussianized prior on S8(i.e.S8=0.766±0.017,determined through the joint analysis of KID1000+BOSS+2dLenS).We find that although the new model maintains the ability to alleviate the Hubble tension to～1.4σ,it still exacerbates the S8 tension to a level similar to that of the axion-like EDE model.
查看更多>>摘要：We study whether it is possible to constrain the Brans-Dicke(BD)theory from the measurement of gravitational waves(GW)released in neutron star-black hole collisions.Considering the scalar field modifications through monopole and dipole radiations,we find additional contributions to the phase evolution in the emitted gravitational waveform.After effectively calculating such effect in the post-Newtonian order,we are in a position to measure the scalar field and give bounds on the BD coupling parameter ωBD.We derive the analytical expression for the phase modification due to the orbital eccentricity of eccentric binaries in both general relativity and BD theory.Employing the Bayesian analysis,we obtain the constraints on ωBD from the GW events,GW200105 and GW200115.
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