There has been a notable surge of interest in neuromorphic network computation, particularly concerning both non-volatile and volatile threshold devices. In this research, we have developed a multi-layer thin film architecture consisting of Al/AlN/Ag/AlN/Pt, which functions as a threshold switching (TS) device characterized by rapid switching speeds of 50 ns and minimal leakage current. We have effectively demonstrated biological neuron-like behaviors, such as threshold-driven spikes, all-or-nothing spikes, intensity-modulated frequency response, and frequency-modulated frequency response, through the deployment of a leaky integrate-and-fire (LIF) artificial neuron circuit, which surpasses earlier neuronal models. The resistance switching mechanism of the device is likely due to the migration of nitrogen vacancies in conjunction with silver filaments. This threshold switching device shows significant potential for applications in next-generation artificial neural networks.

A novel cryogenic MgF molecular beam, characterized by high flux and exceptional stability, has been successfully generated within a helium buffer gas environment. This achievement is facilitated by the innovative use of an in-cell stepper motor, which continuously rotates the sample rod during laser ablation. Through meticulous optimization of the ablation laser energy, the position of the ablation spot, and the gas flow rate, among other critical parameters, the resulting MgF beam exhibits a remarkable forward velocity of 209 m/s and an impressive brightness of approximately 1.36 × 10¹² molecules per pulse per steradian per internal state. Subsequent attempts at one-dimensional Doppler cooling of the MgF beam have been made, with theoretical calculations closely aligning with experimental outcomes. These findings demonstrate a significant compression in the transverse spatial distribution of the molecular beam, from 7.8 to 6.5 mm, and a substantial cooling of the transverse temperature, from 8.1 to 5.6 mK. This work lays a crucial foundation for the advancement of molecular slowing and magneto-optical trapping techniques for MgF molecules.

The Rice−Mele model has been a seminal prototypical model for the study of topological phenomena such as Thouless pumping. Here we implement the interacting Rice−Mele model using a superconducting quantum processor comprising a one-dimensional array of 36 qutrits. By adiabatically cycling the qutrit frequencies and hopping strengths in the parametric space, we emulate the Thouless pumping of single and two bounded microwave photons along the qutrit chain. Furthermore, with strong Hubbard interaction inherent in the qutrits we also emulate the intriguing phenomena of resonant tunneling and asymmetric edge-state transport of two interacting photons. Utilizing the interactions and higher energy levels in such fully controlled synthetic quantum simulators, these results demonstrate new opportunities for exploring exotic topological phases and quantum transport phenomena using superconducting quantum circuits.

Significant progress has been made in high-power ultrafast laser technology since the development of diode-pumped solid-state laser systems. Three main types of diode-pumped laser systems, InnoSlab, fiber, and thin disk lasers, offer highly efficient cooling geometries that are essential for high-power ultrafast amplifiers. These systems employ amplifier chain configurations customized to their individual geometries, scaling the low-power seed lasers to high power via multi-pass, multi-stage, and regenerative amplification techniques. The partially end-pumped InnoSlab amplifier is distinguished by its slab-shaped gain medium and a highly compact design. This design offers a large surface-to-volume ratio, moderate gain per pass, and reduced nonlinear effects, facilitating the amplification of low-power ultrafast seed laser pulses to kilowatt-level output power at high repetition rates in the multi-MHz range. This review highlights the characteristics of InnoSlab technology and its amplifier configurations, discussing recent advancements in new cavity designs aimed at enhancing gain and beam quality. Additionally, it covers the mechanisms of generating high peak power few-cycle pulses, including non-linear post-pulse compression. The review also explores the potential applications of InnoSlab systems for generating extreme ultraviolet (XUV) and terahertz (THz) frequencies.

Fe₃GaTe₂ has attracted significant interest due to its intrinsic room-temperature ferromagnetism, yet its magnetic interactions remain debated. We thoroughly investigate the magnetism of Fe₃GaTe₂ using critical analysis, nitrogen−vacancy (NV) center magnetometry, and Density Function Theory (DFT). Our critical phenomenon analysis with exponents [\beta = 0.3706(9), \gamma = 1.32(6), \delta = 4.7(2)] and DFT calculations reveal competition between itinerant and localized spins driven by anisotropic coupling, which can be attributed to a net charge transfer of approximately 0.22 electrons from Fe³⁺ to surrounding Ge/Te atoms. As confirmed by NV center magnetometry, the ferromagnetism in Fe₃GaTe₂ remains robust even in thin-layered sheet of 16 nm (corresponding to approximately 20 layers). The out-of-plane ferromagnetism in thin Fe₃GaTe₂ sheets is stabilized due to the distinct spin interaction energies between intralayers (J_1 ~ 66.74 meV and J_2 ~ 17.33 meV) and interlayers (J_z ~ 3.78 meV). In addition, the constant energy contour profiles near the Fermi surface of Fe₃GaTe₂ suggest the presence of both hole and electron pockets with a distorted contour around the \mathrm{K}/{\mathrm{K}}^{\mathrm{\prime }} point, indicating hexagonal trigonal warping effects. Furthermore, the layer-resolved electronic band structure uncovers a layer−valley coupling near the Fermi surface, with bands at valleys \mathrm{K} and {\mathrm{K}}^{\mathrm{\prime }} associated with different layers. These findings pave way for advanced electronic applications operating above-room-temperature.

In conventional electrides, excess electrons are localized in crystal voids to serve as anions. Most of these electrides are metallic and the metal cations are primarily from the s-block, d-block, or rare-earth elements. Here, we report a class of p-block metal-based electrides found in bilayer SnO and PbO, which are semiconducting and feature electride states in both the valence band (VB) and conduction band (CB), as referred to 2D “bipolar” electrides. These bilayers are hybrid electrides where excess electrons are localized in the interlayer region and hybridize with the orbitals of Sn atoms in the VB, exhibiting strong covalent-like interactions with neighboring metal atoms. Compared to previously studied hybrid electrides, the higher electronegativity of Sn and Pb enhances these covalent-like interactions, leading to largely enhanced semiconducting bandgap of up to 2.5 eV. Moreover, the CBM primarily arises from the overlap between metal states and interstitial charges, denoting a potential electride and forming a free-electron-like (FEL) state with small effective mass. This state offers high carrier mobilities for both electron and hole in bilayer SnO, suggesting its potential as a promising p-type semiconductor material.

Wave-particle duality as a fundamental tenet of quantum mechanics is crucial for advancing comprehension of quantum theories and developing quantum technologies with practical applications. However, taking into account experimental impact factors to develop a feasible measurement for wave-like and particle-like properties of light fields is an ongoing challenge, and the non-classicality extraction and determination remains to be explored. In this work, feasibly measurable second-order photon correlations based on Hanbury Brown−Twiss and Hong−Ou−Mandel interferences are employed to analyze the evolution of wave−particle duality for various input states. The wave-particle dualities of chaotic, coherent and mixed classical states as functions of time delay and coherence time are investigated. The realistic impacts of background noise, detection efficiency, intensity ratio and phase differences on the wave−particle duality of non-classical (Fock and squeezed coherent) states are unveiled. In noisy backgrounds with low detection efficiencies, efficient enhancement and extraction of non-classicality and a continuous transition from classical to non-classical region are achieved in single photon state mixed with coherent state by adjusting the phase difference from 0 to \pi /2. The non-classicality of squeezed coherent state can be induced by the classical wave-like and particle-like properties. The research provides a practical precision measurement of wave−particle duality that is helpful for the improvement of high-resolution quantum imaging and sensing.

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) materials have unique band structure as well as excellent electrical and optical properties, which exhibit great advantages in optoelectronic devices. Chemical vapor deposition (CVD), a method to realize the synthesis of large-scale 2D TMDs materials, will inevitably introduce defects in the growth process, thus decreasing the performance of 2D TMDs-based optoelectronic devices. In order to fundamentally address this issue, we proposed a method to gradually regulate the reaction concentration of precursor during growth. As a result, the suitable concentration of precursor can effectively enhance the probability of covalent binding of X−M (X: S, Se, etc.; M: Mo, W, etc.), thus suppressing the generation of vacancy defects. Furthermore, we explored sulfur vacancy (V_S) on the performance of 2D molybdenum disulfide-based (MoS₂-based) self-powered devices through constructing p-type silicon/MoS₂ (p-Si/MoS₂) based p–n heterojunction. The photodetector composed of optimized MoS₂ nanosheets exhibited high responsivity (330.14 A·W⁻¹), fast response speed (40 μs/133 μs), and excellent photovoltage stability. This method of regulating the low temperature region during CVD growth can realize the preparation of high-quality TMDs films and be applied in high-performance optoelectronic devices.

Using the integration within ordered products, we obtain the analytical density-operator evolution of the general quadratic state {\rho }_0 in a laser channel, which always maintains the same form as the initial density operator {\rho }_0. Introducing the differential representation of the von-Neumann entropy and two important resemble formulas, we analytically and numerically investigate the entropy evolution of the state {\rho }_0 in a laser channel, which is determined by not only the competition of the gain and loss of the laser channel, but also the coefficients \alpha, \beta of the initial quadratic state {\rho }_0.

Brilliance of the fourth-generation synchrotron radiation sources are increased in the order of magnitude, which further emphasizes the coherent applications. The zoom system of traditional optics can realize coherence regulation while achieving the target size of focus spots at designated position. This paper develops the design method of zoom system to fully exploit partially coherent fields. According to the first-order optics and imaging theory, the design method is reasonably simplified. The flux-optimization acceptance-angle ratio approximately linearly varies with the coherent fraction, which contributes to the slit-aperture determination. In order to validate the design method, wave-optics simulations are conducted in this paper.

Microwave-enhanced laser-induced breakdown spectroscopy (ME-LIBS) is a promising analysis technique for trace element detection with the advantage of high signal intensity. However, the shot-to-shot repeatability of the ME-LIBS signal is relatively low, which affects the precision of the result and limits quantification performance. A cavity confinement microwave-enhanced laser-induced plasma (CC-ME-LIP) modulation method is proposed to improve the repeatability of the ME-LIBS signal. During the plasma evolution, cavity confinement provides an environment that regulates plasma around the microwave probe, controls plasma expansion, and minimizes interaction with the atmosphere. This behavior enhances the stability of the plasma morphology, leading to improved signal repeatability. In addition, confinement increases the energy transfer process within the plasma by the superimposition of two methods, resulting in a stronger signal intensity. The CC-ME-LIP modulation method is applied to the brass sample. The relative standard deviation (RSD) of the different copper and zinc lines has been reduced, along with an improvement of the intensity enhancement factor (IEF). For example, Cu 521.820 nm line RSD reduced from 29.11% (ME-LIBS) to 17.12% (CC-ME-LIBS) with an IEF of 1.08. The result demonstrated that the proposed approach significantly improves the repeatability of the ME-LIBS signal, thereby increasing the overall signal quality. To gain a deeper understanding, a detailed analysis of the mechanisms behind the increased signal intensity and improved repeatability was further investigated.

In a recent paper [Jiang, et al., Science 370, 1447 (2020)], it was reported that zero reflection or Klein tunneling can be observed for normally incident quasiparticles upon a potential barrier constructed by two phononic crystals (PCs) with Dirac cone band structures. Here, we develop a first-principles approach for accurate computation of the reflection of quasiparticles by a potential step with two PCs at normal incidence. Strikingly, it is found that minimal reflection of quasiparticles (R_m = 0.8%) occurs at an energy below the potential step, while moderate reflection (R_d = 17%) remains at the center energy of the potential step, even with the PCs adopted by Jiang et al. A physical model is presented to understand such phenomena, where the zigzag interface in the step serves as a graded antireflection layer and reflection increases dramatically near the band gap of PCs. Two solutions are also shown for realizing lower R_d or even ideal Klein tunneling in PCs, with reducing the difference between the two PCs or enhancing the antireflection effect of the interface. Our work reveals the effects of the zigzag interface and band gap on Klein tunneling in PCs, which will be inspiring for exploring more fascinating phenomena of quasiparticles in classical wave systems.

Entanglement and quantum correlations between atoms are not usually considered key ingredients of the superradiant phase transition. Here we consider the Tavis−Cummings model, a solvable system of two-levels atoms, coupled with a single-mode quantized electromagnetic field. This system undergoes a superradiant phase transition, even in a finite-size framework, accompanied by a spontaneous symmetry breaking, and an infinite sequence of energy level crossings. We find approximated expressions for the ground state, its energy, and the position of the level crossings, valid in the limit of a very large number of photons with respect to that of the atoms. In that same limit, we find that the number of photons scales quadratically with the coupling strength, and linearly with the system size, providing a new insight into the superradiance phenomenon. Resorting to novel multipartite measures, we then demonstrate that this quantum phase transition is accompanied by a crossover in the quantum correlations and entanglement between the atoms (qubits). The latters therefore represent suited order parameters for this transition. Finally, we show that these properties of the quantum phase transition persist in the thermodynamic limit.

Variational quantum algorithms have been widely demonstrated in both experimental and theoretical contexts to have extensive applications in quantum simulation, optimization, and machine learning. However, the exponential growth in the dimension of the Hilbert space results in the phenomenon of vanishing parameter gradients in the circuit as the number of qubits and circuit depth increase, known as the barren plateau phenomena. In recent years, research in non-equilibrium statistical physics has led to the discovery of the realization of many-body localization. As a type of floquet system, many-body localized floquet system has phase avoiding thermalization with an extensive parameter space coverage and has been experimentally demonstrated can produce time crystals. We applied this circuit to the variational quantum algorithms for the calculation of many-body ground states and studied the variance of gradient for parameter updates under this circuit. We found that this circuit structure can effectively avoid barren plateaus. We also analyzed the entropy growth, information scrambling, and optimizer dynamics of this circuit. Leveraging this characteristic, we designed a new type of variational ansatz, called the “many-body localization ansatz”. We applied it to solve quantum many-body ground states and examined its circuit properties. Our numerical results show that our ansatz significantly improved the variational quantum algorithm.