查看更多>>摘要：This concise review summarizes recent advancements in theoretical studies of vortex quantum droplets(VQDs)in matter-wave fields.These are robust self-trapped vortical states in two-and three-dimensional(2D and 3D)Bose-Einstein condensates(BECs)with intrinsic nonlinearity.Stability of VQDs is provided by additional nonlinearities resulting from quantum fluctuations around mean-field states,often referred to as the Lee-Huang-Yang(LHY)corrections.The basic models are presented,with emphasis on the interplay between the mean-field nonlinearity,LHY correction,and spatial dimension,which determines the structure and stability of VQDs.We embark by delineating fundamental properties of VQDs in the 3D free space,followed by consideration of their counterparts in the 2D setting.Additionally,we address stabilization of matter-wave VQDs by optical potentials.Finally,we summarize results for the study of VQDs in the single-component BEC of atoms carrying magnetic moments.In that case,the anisotropy of the long-range dipole-dipole interactions endows the VQDs with unique characteristics.The results produced by the theoretical studies in this area directly propose experiments for the observation of novel physical effects in the realm of quantum matter,and suggest potential applications to the design of new schemes for processing classical and quantum information.
查看更多>>摘要：We report a passive mode-locked fiber laser that can realize single-wavelength tuning and multi-wavelength spacing tuning simultaneously.The tuning range is from 1528 nm-1560 nm,and up to three bands of soliton states can be output at the same time.These results are confirmed by a nonlinear Schrödinger equation model based on the split-step Fourier method.In addition,we reveal a way to transform the multi-wavelength soliton state into the Q-switched mode-locked state,which is period doubling.These results will promote the development of optical communication,optical sensing and multi-signal pulse emission.
查看更多>>摘要：Coupling of quantum-dot circuits to microwave photons enables us to investigate photon-assisted quantum transport.Here,we revisit this typical circuit quantum electrodynamical setup by introducing the Kerr non-linearity of photons.By exploiting quantum critical behavior,we propose a powerful scheme to control the power-harvesting efficiency in the microwave regime,where the driven-dissipative optical system acts as an en-ergy pump.It drives electron transport against a load in the quantum-dot circuit.The energy transfer and,consequently,the harvesting efficiency are enhanced near the critical point.As the critical point moves towards to low input power,high efficiency within experimental parameters is achieved.Our results complement funda-mental studies of photon-to-electron conversion at the nanoscale and provide practical guidance for designs of integrated photoelectric devices through quantum criticality.
查看更多>>摘要：The structure of light diquarks plays a crucial role in formation of exotic hadrons beyond the conventional quark model,especially with regard to the line shapes of bottomed hadron decays.We study the two-body hadronic weak decays of bottomed baryons and bottomed mesons to probe the light diquark structure and to pin down the quark-quark correlations in the diquark picture.It is found that the light diquark does not favor a compact structure.For instance,the isoscalar diquark[ud]in ∧0b can be easily split and rearranged to formΣ(*)c(D)(*)via the color-suppressed transition.This provides a hint that the hidden charm pentaquark states produced in ∧0b decays could be the Σ(*)c(D)(*)hadronic molecular candidates.This quantitative study resolves the apparent conflicts between the production mechanism and the molecular nature of these Pc states observed in experiment.
查看更多>>摘要：Within the extended vector meson dominance model,we investigate the e+e-→ ∧+c(∧)-c reaction and the electromagnetic form factors of the charmed baryon ∧+c.The model parameters are determined by fitting them to the cross sections of the process e+e-→ ∧+c(∧)-c and the magnetic form factor |GM| of ∧+c.By considering four charmonium-like states,called φ(4500),φ(4660),φ(4790),and φ(4900),we can well describe the current data on the e+e-→ ∧+c(∧)-c reaction from the reaction threshold up to 4.96 GeV.In addition to the total cross sections and |GM|,the ratio |GE/GM| and the effective form factor |Geff| for ∧+c are also calculated,and found that these calculations are consistent with the experimental data.Within the fitted model parameters,we have also estimated the charge radius of the charmed ∧+c baryon.
查看更多>>摘要：Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-critical-density plasmas.It is found theoretically and numerically that the radiation pressure of a circularly polarized laser pulse first compresses the plasma electrons to form a dense flying mirror with a relativistic high speed.The pulse reflected by the mirror is red-shifted to the mid-infrared range.Full three-dimensional simulations demonstrate that the central wavelength of the mid-infrared pulse is tunable from 3 μm to 14 μm,and the laser energy conversion efficiency can reach as high as 13％.With a 0.5-10 PW incident laser pulse,the generated mid-infrared pulse reaches a peak power of 10-180 TW,which is interesting for various applications in ultrafast and high-field sciences.
查看更多>>摘要：In the existing ghost-imaging-based cryptographic key distribution(GCKD)protocols,the cryptographic keys need to be encoded by using many modulated patterns,which undoubtedly incurs long measurement time and huge memory consumption.Given this,based on snapshot compressive ghost imaging,a public network crypto-graphic key distribution protocol is proposed,where the cryptographic keys and joint authentication information are encrypted into several color block diagrams to guarantee security.It transforms the previous single-pixel sequential multiple measurements into multi-pixel single exposure measurements,significantly reducing sampling time and memory storage.Both simulation and experimental results demonstrate the feasibility of this protocol and its ability to detect illegal attacks.Therefore,it takes GCKD a big step closer to practical applications.
查看更多>>摘要：Semiconductor devices are often operated at elevated temperatures that are well above zero Kelvin,which is the temperature in most first-principles density functional calculations.Computational approaches to com-puting and understanding the properties of semiconductors at finite temperatures are thus in critical demand.In this review,we discuss the recent progress in computationally assessing the electronic and phononic band structures of semiconductors at finite temperatures.As an emerging semiconductor with particularly strong temperature-induced renormalization of the electronic and phononic band structures,halide perovskites are used as a representative example to demonstrate how computational advances may help to understand the band struc-tures at elevated temperatures.Finally,we briefly illustrate the remaining computational challenges and outlook promising research directions that may help to guide future research in this field.
查看更多>>摘要：Motivated by recent realizations of spin-1 NaRb mixtures in the experiments[Phys.Rev.Lett.114,255301(2015);Phys.Rev.Lett.128,223201(2022)],we investigate heteronuclear magnetism in the Mott-insulating regime.Different from the identical mixtures where the boson statistics only admits even parity states from angular momentum composition,for heteronuclear atoms in principle all angular momentum states are allowed,which can give rise to new magnetic phases.While various magnetic phases can be developed over these degen-erate spaces,the concrete symmetry breaking phases depend on not only the degree of degeneracy but also the competitions from many-body interactions.We unveil these rich phases using the bosonic dynamical mean-field theory approach.These phases are characterized by various orders,including spontaneous magnetization order,spin magnitude order,singlet pairing order,and nematic order,which may coexist specially in the regime with odd parity.Finally we address the possible parameter regimes for observing these spin-ordered Mott phases.
查看更多>>摘要：We propose a quasi-one-dimensional non-Hermitian Creutz ladder with an entirely flat spectrum by intro-ducing alternating gain and loss components while maintaining inversion symmetry.Destructive interference generates a flat spectrum at the exceptional point,where the Creutz ladder maintains coalesced and degenerate eigenvalues with compact localized states distributed in a single plaquette.All excitations are completely confined within the localization area,unaffected by gain and loss.Single-site excitations exhibit nonunitary dynamics with intensities increasing due to level coalescence,while multiple-site excitations may display oscillating or constant intensities at the exceptional point.These results provide insights into the fascinating dynamics of non-Hermitian localization,where level coalescence and degeneracy coexist at the exceptional point.
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