查看更多>>摘要：We propose a scheme to realize antibunched multiple-photon bundles based on phonon blockade in a quadratically coupled optomechanical system.Through adjusting the detunings to match the conditions of phonon blockade in the photon sidebands,we establish super-Rabi oscilla-tion between zero-photon state and multiple-photon states with adjustable super-Rabi frequencies under appropriate single-phonon resonant condi-tions.Taking the system dissipation into account,we numerically calculate the standard and generalized second-order functions of the cavity mode as well as the quantum trajectories of the state populations with Monte Carlo simulation to confirm that the emitted photons form antibunched multi-ple-photon bundles.Interestingly,the desirable n-photon states are recon-structed after a direct phonon emission based on phonon blockade,and thus the single-phonon emission heralds the cascade emission of n-photon bundles.Our proposal shows that the optomechanical system can simulta-neously behave as antibunched multiple-photon emitter and single-phonon gun.Such a nonclassical source could have potential applications in quantum information science.
查看更多>>摘要：The curved surface has emerged as new research platform for understand-ing and manipulating novel electromagnetic behaviors in complex media.In this paper,we explore the anisotropic polaritons on the spherical surface based on Maxwell's fish-eye metric through stereographic projec-tion.Additionally,this phenomenon can be extended to spindle surface by conformal mapping.Our calculations and simulations demonstrate the elliptic and hyperbolic polaritons,excited by an electric dipole on the sphere,will self-focus or focus on the poles on the sphere affected by anisotropic permittivity.Furthermore,we reveal the optical singularity nature of the curved hyperbolic polaritons from the perspective of trans-formation optics by obtaining the equivalent optical refractive index profiles and the particle potential energy.Based on natural anisotropic materials and metamaterials,the curved polaritons have potential applica-tions in curved surface focusing and chaos regulation.This work not only bridges the transformation optics and anisotropic polaritons at curved surface,but also provides a new route to surface optical field manipula-tion.
查看更多>>摘要：The spectral form factor(SFF)can probe the eigenvalue statistic at different energy scales as its time variable varies.In closed quantum chaotic systems,the SFF exhibits a universal dip-ramp-plateau behavior,which reflects the spectrum rigidity of the Hamiltonian.In this work,we explore the general properties of SFF in open quantum systems.We find that in open systems the SFF first decays exponentially,followed by a linear increase at some intermediate time scale,and finally decreases to a saturated plateau value.We derive general relations between(i)the early-time decay exponent and Lindblad operators;(ii)the long-time plateau value and the number of steady states.We also explain the effective field theory perspective of general behaviors.We verify our theoretical predictions by numerically simulating the Sachdev-Ye-Kitaev(SYK)model,random matrix theory(RMT),and the Bose-Hubbard model.
查看更多>>摘要：In recent years,cat-state encoding and high-dimensional entanglement have attracted much attention.However,previous works are limited to generation of entangled states of cat-state qubits(two-dimensional entan-glement with cat-state encoding),while how to prepare entangled states of cat-state qutrits or qudits(high-dimensional entanglement with cat-state encoding)has not been investigated.We here propose to generate a maxi-mally-entangled state of multiple cat-state qutrits(three-dimensional entanglement by cat-state encoding)in circuit QED.The entangled state is prepared with multiple microwave cavities coupled to a superconducting flux ququart(a four-level quantum system).This proposal operates essen-tially by the cavity-qutrit dispersive interaction.The circuit hardware resource is minimized because only a coupler ququart is employed.The higher intermediate level of the ququart is occupied only for a short time,thereby decoherence from this level is greatly suppressed during the state preparation.Remarkably,the state preparation time does not depend on the number of the qutrits,thus it does not increase with the number of the qutrits.As an example,our numerical simulations demonstrate that,with the present circuit QED technology,the high-fidelity preparation is feasible for a maximally-entangled state of two cat-state qutrits.Furthermore,we numerically analyze the effect of the inter-cavity crosstalk on the scalability of this proposal.This proposal is universal and can be extended to accom-plish the same task with multiple microwave or optical cavities coupled to a natural or artificial four-level atom.
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