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Bessel vortices in spin-1 Bose-Einstein condensates with Zeeman splitting and spin-orbit coupling

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Chinese physics B 2024年第10期33卷 159-165页

作者： Huan-Bo Luo Xin-Feng Zhang Runhua Li Yongyao Li Bin Liu department of physics South China University of TechnologyGuangzhou 510640China School of physics and Optoelectronic engineering Foshan UniversityFoshan 528000China

We investigate the ground states of spin-orbit coupled spin-1 Bose-Einstein condensates in the presence of Zeeman *** introducing the generalized momentum operator,the linear version of the system is solved exactly,yielding a set of Bessel ***,based on linear solution and using variational approximation,the solutions for the full nonlinear system and their ground state phase diagrams are derived,including the vortex states with quantum numbers m=0,1,as well as mixed *** this work,mixed states in spin-1 spin-orbit coupling(SOC)BEC are interpreted for the first time as weighted superpositions of three vortex ***,the results also indicate that under strong Zeeman splitting,the system cannot form localized *** variational solutions align well with numerical simulations,showing stable evolution and meeting the criteria for long-term observation in experiments.

关键词： spin-orbit coupling Bessel vortices variational method

Emerging direct current triboelectric nanogenerator for high-entropy mechanical energy harvesting

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Science China(Technological Sciences) 2024年第5期67卷 1297-1316页

作者： CHEN Jie GUO RuiLong GUO HengYu College of physics and Electronic engineering Chongqing Normal UniversityChongqing 401331China department of Applied physics Chongqing UniversityChongqing 401331China

In the era of the Internet of Things(IoT),the provision of sustainable power to distributed,mobile,and low-power-consumption electronic devices is a critical *** overcome this challenge,the triboelectric nanogenerator(TENG),a highly efficient high-entropy mechanical energy harvesting device,was developed in *** device enables the direct conversion of irregular and low-frequency mechanical energy into pulsed alternating current(AC)***,the incompatibility of most electronic devices with AC signals necessitates rectifier circuits or generators that deliver direct current(DC)*** recent years,DC-TENGs have undergone extensive development,achieving significant milestones in various application fields while also facing crucial challenges that require *** this review,three categories of DC-TENG devices with distinct operating mechanisms are comprehensively explored:multiphase coupling,mechanical rectification,and air *** typical structures and working mechanisms are thoroughly discussed,and specific output performance limitations,along with corresponding optimization strategies,are ***,the applications of DC-TENGs in various scenarios are ***,the challenges faced by DC-TENGs and potential solutions are analyzed to guide further advancements in this technology.

关键词： TENG direct current working mechanisms output performance limitations optimization strategies

Density of excess modes below the first phonon mode in four-dimensional glasses

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Chinese physics B 2024年第7期33卷 483-489页

作者：王利近胥鼎张世允 School of physics and Optoelectronic engineering Anhui UniversityHefei 230601China department of physics University of Science and Technology of ChinaHefei 230026China

Glasses are known to possess low-frequency excess modes beyond the Debye *** decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law scaling:D(ω)~ω~γ.However,it remains debated on the value of γ at low frequencies below the first phonon-like mode in finitesize *** simulation studies reported γ=4 at low frequencies in two-(2D),three-(3D),and four-dimensional(4D)glasses,whereas recent observations in 2D and 3D glasses suggested γ=3.5 in a lower-frequency *** is uncertain whether the low-frequency scaling of D(ω)~ω^(3.5) could be generalized to 4D ***,we conduct numerical simulation studies of excess modes at frequencies below the first phonon-like mode in 4D model *** is found that the system size dependence of D(ω) below the first phonon-like mode varies with spatial dimensions:D(ω) increases in2D glasses but decreases in 3D and 4D glasses as the system size ***,we demonstrate that the ω^(3.5)scaling,rather than the ω~4 scaling,works in the lowest-frequency regime accessed in 4D glasses,regardless of interaction potentials and system sizes ***,our findings in 4D glasses,combined with previous results in 2D and 3D glasses,suggest a common low-frequency scaling of D(ω)~ ω^3.5) below the first phonon-like mode across different spatial dimensions,which would inspire further theoretical studies.

关键词： vibrational density of states excess modes four-dimensional glasses scaling computer simulation

Tuning structural,electrical,dielectric and magnetic properties of Mg-Cu-Co ferrites via dysprosium(Dy^(3+))doping

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Journal of Rare Earths 2024年第1期42卷 137-146,I0005页

作者： Maria Akhtar M.S.Hasan Nasir Amin N.A.Morley Muhammad Imran Arshad department of physics Government College UniversityFaisalabad38000Pakistan department of physics The University of Lahore53700Pakistan department of Materials Science and engineering The University of SheffieldS13JDUK department of physics&Astronomy University College LondonUK

In current research work,Dy3+substituted Mg0.5Cu0.25Co0.25Fe2-xDyxO4(0.0≤x≤0.04 with the step interval of 0.01)soft ferrites were synthesized by the sol-gel auto combustion *** prepared samples were characterized by the techniques using X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared(FTIR)spectroscopy,curre nt-voltage(Ⅰ-Ⅴ)measurement,LCR meter,vibrating sample magnetometer(VSM)and *** data reveal that the average crystallite size is 49.71 nm and the lattice constant is 0.83703 nm for sample x=*** non-uniform grain growth was demonstrated by micrographs and impurity-free elemental composition was observed from EDX *** DC resistivity has an increasing and decreasing trend in ferromagnetic and paramagnetic regions with an increase in ***,the high resistivity is observed with the order of 1010Ω·cm,and the activation energy is 0.944 eV for samples x=*** dielectric parameters including dielectric constant,dielectric losses,and impedance gradually decrease with the increase in frequency from 8 Hz to 8 *** minimum dielectric loss at high frequency is found for sample x=*** coercivity(Hc)and saturation magnetization(Ms)are found in the ranges of 520.82-544.02 Oe and 20.5841-21.1473 emu/g,*** observations confirm that dysprosium(x=0.03)doped MCC-soft ferrites may be applicable in transformer cores,microwave absorbance,and telecommunication devices.

关键词： Soft ferrites DC resistivity Dielectric loss Impedance Coercivity Rare earths

Footprints of axion-like particle in pulsar timing array data and James Webb Space Telescope observations

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Science China(physics,Mechanics & Astronomy) 2024年第11期67卷 55-62页

作者： Shu-Yuan Guo Maxim Khlopov Xuewen Liu Lei Wu Yongcheng Wu Bin Zhu department of physics Yantai UniversityYantai 264005 China Institute of physics Southern Federal UniversityRostov on Don 344090 Russia National Research Nuclear university MEPhI(Moscow engineering physics Institute) Moscow 115409 Russia Virtual Institute of Astroparticle physics Paris 75018 France department of physics and Institute of Theoretical physics Nanjing Normal UniversityNanjing 210023 China

Several pulsar timing array(PTA) collaborations have recently reported the evidence for a stochastic gravitational-wave background(SGWB), which can unveil the formation of primordial seeds of inhomogeneities in the early universe. With the SGWB parameters inferred from PTAs data, we can make a prediction of the seeds for early galaxy formation from the domain walls in the axion-like particles(ALPs) field distribution. This also naturally provides a solution to the observation of high redshifts by the James Webb Space Telescope. The predicted photon coupling of the ALP is within the reach of future experimental searches.

关键词： stochastic gravitational-wave background pulsar timing array axion-like particle JWST

Reconstructing coherent dynamics of bound states induced by strong attosecond XUV pulses

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Chinese Optics Letters 2024年第2期22卷 56-63页

作者：贾利娟刘明清王新强徐龙闫培光姜维超傅立斌 Institute of Quantum Precision Measurement College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China department of physics Xiamen UniversityXiamen 361005China Graduate School of China Academy of engineering physics Beijing 100193China

We propose a scheme that utilizes weak-field-induced quantum beats to investigate the electronic coherences of atoms driven by a strong attosecond extreme ultraviolet(XUV)*** technique involves using a strong XUV pump pulse to excite and ionize atoms and a time-delayed weak short pulse to probe the photoelectron *** theoretical analysis demonstrates that the information regarding the bound states,initiated by the strong pump pulse,can be precisely reconstructed from the weak-field-induced quantum beat *** examine this scheme,we apply it to the attosecond XUV laser-induced ionization of hydrogen atoms by solving a three-dimensional time-dependent Schr?dinger *** work provides an essential reference for reconstructing the ultrafast dynamics of bound states induced by strong XUV attosecond pulses.

关键词： attosecond pulse bound-state dynamics quantum beats

Control system design for a pressure-tube-type supercritical water-cooled nuclear reactor via a higher order sliding mode method

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Nuclear Science and Techniques 2024年第1期35卷 145-154页

作者： M.Hajipour G.R.Ansarifar department of Nuclear engineering Faculty of PhysicsUniversity of IsfahanIsfahan 81746-73441Iran

Nuclear power plants exhibit non-linear and time-variable ***,designing a control system that sets the reactor power and forces it to follow the desired load is complicated.A supercritical water reactor(SCWR)is a fourth-generation conceptual *** an SCWR,the non-linear dynamics of the reactor require a controller capable of control-ling the *** this study,a pressure-tube-type SCWR was controlled during reactor power maneuvering with a higher order sliding mode,and the reactor outgoing steam temperature and pressure were controlled *** an SCWR,the temperature,pressure,and power must be maintained at a setpoint(desired value)during power *** point kinetics equations with three groups of delayed neutrons were used in the ***-order and classic sliding mode controllers were separately manufactured to control the plant and were compared with the PI controllers speci-fied in previous *** controlled parameters were reactor power,steam temperature,and ***,for these parameters,the PI controller had certain instabilities in the presence of *** classic sliding mode controller had a higher accuracy and stability;however its main drawback was the chattering *** was highly accurate and stable and had a small computational *** reality,it followed the desired values without oscillations and chattering.

关键词： Supercritical water nuclear reactor Higher order sliding mode controller Steam temperature Steam pressure Point kinetics model

Dynamical control of nanoscale light-matter interactions in low-dimensional quantum materials

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Light(Science & Applications) 2024年第2期13卷 236-253页

作者： Yeonjeong Koo Taeyoung Moon Mingu Kang Huitae Joo Changjoo Lee Hyeongwoo Lee Vasily Kravtsov Kyoung-Duck Park department of physics Pohang University of Science and Technology(POSTECH)Pohang37673Republic of Korea School of physics and engineering ITMO UniversitySaint Petersburg197101Russia

Tip-enhanced nano-spectroscopy and-imaging have significantly advanced our understanding of low-dimensional quantum materials and their interactions with light,providing a rich insight into the underlying physics at their natural length ***,various functionalities of the plasmonic tip expand the capabilities of the nanoscopy,enabling dynamic manipulation of light-matter interactions at the *** this review,we focus on a new paradigm of the nanoscopy,shifting from the conventional role of imaging and spectroscopy to the dynamical control approach of the tip-induced light-matter *** present three different approaches of tip-induced control of light-matter interactions,such as cavity-gap control,pressure control,and near-field polarization ***,we discuss the nanoscale modifications of radiative emissions for various emitters from weak to strong coupling regime,achieved by the precise engineering of the ***,we introduce recent works on light-matter interactions controlled by tip-pressure and near-field polarization,especially tunability of the bandgap,crystal structure,photoluminescence quantum yield,exciton density,and energy transfer in a wide range of quantum *** envision that this comprehensive review not only contributes to a deeper understanding of the physics of nanoscale light-matter interactions but also offers a valuable resource to nanophotonics,plasmonics,and materials science for future technological advancements.

关键词： quantum precise shifting

Effects of cross-Kerr coupling on transmission spectrum of double-cavity optomechanical system

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Chinese physics B 2024年第6期33卷 390-396页

作者：陈立滕秦立国田立君黄接辉周南润龚尚庆 School of Mathematics Physics and StatisticsShanghai University of Engineering ScienceShanghai 201620China department of physics Shanghai UniversityShanghai 200444China School of Electrical engineering Shanghai University of Engineering ScienceShanghai 201620China School of physics East China University of Science and TechnologyShanghai 200237China

We theoretically study the transmission spectrum of the cavity field in a double-cavity optomechanical system with cross-Kerr(CK) effect. The system consists of two tunneling coupling optomechanical cavities with a mechanical resonator as a coupling interface. By doping CK medium into the mechanical resonator, CK couplings between the cavity fields and the mechanical resonator are introduced. We investigate the effects of CK coupling strength on the transmission spectrum of the cavity field, including the transmission rate, nonreciprocity and four-wave mixing(FWM). We find that the transmission spectrum of the probe field can show two obvious transparent windows, which can be widened by increasing the CK coupling strength. For the transmission between the two cavity fields, the perfect nonreciprocity and reciprocity are present and modulated by CK coupling and phase difference between two effective optomechanical couplings. In addition, the effects of the optomechanical and CK couplings on FWM show that the single peak of FWM is split into three symmetrical peaks due to the introduction of the CK effect.

关键词： cross-Kerr transmission rate nonreciprocity four-wave mixing