This paper investigates the ground states and complex dynamics of vortices in spin-orbit-coupled BoseEinstein condensates subjected to a position-dependent detuning. By scanning the detuning gradient and solving the coupled Gross-Pitaevskii equations, we obtain static vortex lattice structures containing one to six vortices. When the detuning gradient is quenched below its initial value, these vortex lattices exhibit novel periodic rotation motion, with the stability persisting for up to 1000 ms. Notably, depending on the quenched gradient, the twin vortices exhibit two distinct modes: a scissorslike oscillation and unidirectional clockwise rotation. We quantitatively analyze this dynamics and establish direct correspondence between the rotation and the underlying magnetic field gradients experienced by the condensates. When the quenched detuning gradient exceeds its initial value, new vortices are generated. Our findings not only elucidate the rich response of vortices to synthetic magnetic fields but also provide a potential theoretical scheme for the development of ultracold-atom-based magnetic-field gradiometers.

We investigate the formation of moir & eacute; quasicrystal patterns in Bose gasses confined in twisted bilayer optical lattices via Floquet-engineered intralayer atomic interactions. The time evolution of the total density wave amplitude exhibit the stage for the emergence of moir & eacute; quasicrystal patterns, where the pattern formation is closely associated with the momenta of collective modes excited by the weak periodic drive. Through analyzing the radial and angular density wave amplitude, we find that these new collective modes are only coupled radially and cannot be decoupled eventually. The symmetry of quasicrystal patterns can be easily manipulated by the modulation frequencies and amplitudes. Reducing the frequencies and increasing the amplitudes can both facilitate lattice symmetry breaking and the subsequent emergence of rotational symmetry. Notably, a twelve-fold quasicrystal pattern emerges under specific parameters, closely resembling the moir & eacute; quasicrystal in twisted bilayer graphene. The momentum-space distributions also exhibit high rotational symmetry, which is consistent with the real-space patterns at specific evolution times. Our findings establish a new quantum platform for exploring quasicrystals and their symmetry properties in ultracold bosonic systems.

We investigate how wave-mixing (WM)-induced symmetry breaking leads to giant third-order polarization rotation of a weak probe field in a Rydberg electromagnetically induced transparency (EIT) medium. A far-detuned counterpropagating WM field is adiabatically eliminated and retained solely as a Raman dressing of the lower Zeeman manifold. In this reduced description, the weak static magnetic field defines the two circular propagation channels, while the WM-induced Raman coherence breaks the symmetry between these channels, without acting as a gain channel or an independent nonlinear source. The weak-probe response is calculated using a reduced density-matrix expansion for van der Waals (vdW) correlations and self-consistent Maxwell-Bloch propagation, with the nonlinear rotation extracted by subtracting the linear propagation background. Including WM dressing increases the extracted third-order rotation from 1.06 degrees to 25.70 degrees, an enhancement of more than 24 times, for the parameters considered. The response is nonmonotonic in WM strength and can even reverse sign, revealing that the WM field controls the propagation channels through symmetry breaking rather than merely amplifying the probe. Eigenchannel diagnostics further indicate that this giant rotation requires coherent excitation of both WM-dressed propagation channels, which in turn depends on three factors: Raman-induced asymmetry, the EIT-supported Rydberg pathway, and vdW nonlocality. These results demonstrate a symmetry-breaking-controlled mechanism for Rydberg magneto-optics, with applications to weak-light polarimetry and all-optical polarization control.

We investigate the spin Faraday pattern formation in a periodically driven, pancake-shaped spin-orbit-coupled (SOC) Bose-Einstein condensate (BEC) prepared with stripe phase. By modulating atomic interactions using in-phase and out-of-phase schemes, we observe collective excitation modes with distinct rotational symmetries (L-fold). Crucially, at the critical modulation frequency, out-of-phase modulation destabilizes the L = 6 pattern, whereas in-phase modulation not only preserves high symmetry but also excites higher-order modes. Unlike conventional binary BECs, Faraday patterns emerge here without initial noise due to SOC-induced symmetry breaking, with all patterns exhibiting supersolid characteristics. Furthermore, we demonstrate control over pattern symmetry, radial nodes, and pattern radius by tuning the modulation frequency, providing a new approach for manipulating quantum fluid dynamics. This work establishes a platform for exploring supersolidity and nonlinear excitations in SOC systems with stripe phase.

Heterogeneous graphs are ubiquitous in the real world. Recent methods aim to obtain meaningful low-dimensional node embeddings from heterogeneous graphs to facilitate downstream applications. However, most existing methods tend to consider the local information but ignore the non-local information. This paper proposes a novel Non-Local Information Aggregated Graph Neural Network (NLA-GNN) that aggregate not only the local information from neighbor nodes but also non-local information from distant nodes. Specifically, Local aggregation modules in NLA-GNN utilize the attention mechanism to generate potentially valuable metapaths and use them to aggregate local information. In contrast, non-local aggregation modules adopt a two-step approach, and each step uses an attention-guided method to sort nodes into node sequences and aggregate information with the methods designed for sequential data. Experiment results on three heterogeneous graph datasets demonstrate the performance of NLA-GNN over state-of-the-arts and the necessity of non-local aggregation in heterogeneous graphs.

We investigate the ground states and rich dynamics of vortices in spin-orbit coupled Bose-Einstein condensates (BEC) subject to position-dependent detuning. Such a detuning plays the role of an effective rotational frequency, causing the generation of a synthetic magnetic field. Through scanning the detuning gradient, we numerically obtain static vortex lattice structures containing 1 to 6 vortices using the coupled Gross-Pitaevskii equations. When quenching detuning gradient below its initial value, the vortex lattices exhibit interesting periodic rotation motion, and their dynamical stability can persist for up to 1000ms. In particular, depending on the detuning gradient, the twin vortices exhibit either a scissors-like rotational oscillation or a clockwise periodic rotation, reflecting the response to the magnetic field gradient experienced by the condensates. We fit the numerical results to quantitatively analyze the relation between rotation dynamics and magnetic field gradients. When quenching the detuning gradient beyond its initial value, additional vortices appear. Our findings may motivate further experimental studies of vortex dynamics in synthetic magnetic fields and offer insights for engineering a BEC-based magnetic field gradiometer.

We investigate parametric excitation and pattern formation in a harmonically trapped two-component Bose-Einstein condensate. Near the miscible-immiscible phase transition, the excitations of total density and spin density are decoupled. By periodically modulating the atomic scattering lengths, spin-dependent Faraday patterns can be generated with the two components exhibiting an out-of-phase density oscillation. In an elongated condensate, the density pattern along the longitudinal direction corresponds to a one-dimensional spin Faraday pattern, where the modulation frequency and the spatial oscillation period are related to the velocity of the spin sound. After the spin pattern is fully developed, the system quickly enters a nonlinear destabilization regime. For a pancake-shaped condensate, a two-dimensional Faraday pattern is generated with an interesting l-fold rotational symmetry. The number of nodes along the radial and angular directions increases with larger modulation frequencies. We also compare the growth rates of spin Faraday patterns generated with different modulation protocols, which are accessible to current experiments.

The quasi-bound states in the continuum (QBIC) have drawn increasing attention in optical metasurfaces derived from their ultrahigh quality factors, and show the utility to enhance the sensitivity of optical sensing. However, conventional single-resonance sensing may be inaccurate and unreliable, and then the dual-resonance sensing governed by the coupled QBIC is desired but remains elusive. Here, we show that the coupled QBIC modes can be leveraged to unfold dual-resonance refractive index sensing in the hybrid all-dielectric metasurface. Specifically, it is revealed that the toroidal dipole mode can be realized with strong electric field enhancement, enabling the implementation of anapole mode in the telecom short-wavelength band (1460–1530 nm). Under different linearly polarized illuminations, the dual symmetry-protected QBIC modes dominated by the electric quadrupole resonance can be fulfilled in the telecom extended-wavelength band (1360–1460 nm). Within this framework, the polarization-dependent dual symmetry-protected QBIC modes selectively coupled with the toroidal dipole mode or the anapole mode can not only uncover the transformation from Fano resonance to analog of electromagnetically induced transparency, but also manifest two types of high-sensitivity dual-resonance refractive index sensing in the telecom extended-wavelength and short-wavelength bands. The dual-resonance refractive index sensing can also be extended to telecom long-wavelength band (1565–1625 nm) and ultra-long-wavelength band (1625–1675 nm) with enhanced sensitivity. These results offer exploration potential for multi-channel sensing, optical modulators, and slow-light devices.

This paper investigates the formation of Spin Faraday waves in spin -orbit -coupled Bose-Einstein condensate under the stripe phase and explores the dispersion relation under three different phases. We discover that the SFW exhibit temporal and spatial patterns, and appear with resonant waves and higher order harmonics when the interaction is modulated periodically. SFW can be excited even when the modulation frequency resonates with the trap frequency. Furthermore, we study the dispersion relation of these Faraday modes through periodic modulation, which agrees well with our theoretical results under three quantum phases. Our work indicates novel physical phenomena originating from the introduction of spin -orbit coupling and provides a possible method for studying the dispersion of Bose gases.

Oxide-derived copper (OD-Cu)-based materials containing Cu delta+ (0 < delta < 1) have been considered as promising electrocatalysts for electrochemical CO2 reduction reaction (ECO2RR) to produce valuable C-2 products, which, however, suffer from poor stability, mainly due to the inevitable reduction of Cu delta+. We report here that the benzyl alcohol (BA) introduced in catholyte presents a markedly positive effect on the durability and C-2 selectivity enhancement of ECO2RR when OD-Cu-based material is adopted as cathode electrocatalyst. The critical evidence of ECO2RR intermediates has been provided by in situ Raman and FTIR spectroscopy, which reveals the surface mechanisms of BA-assisted ECO2RR over OD-Cu catalysts. On the one hand, the introduction of BA increases the C-2 supply for ECO2RR by slowing down its neutralizing reaction, which results in the increased intermediate species coverage on the catalytic surface therefore the delayed self-reduction of Cu delta+; On the other hand, the interaction between BA and the intermediate species *CO during ECO2RR brings an enhanced selectivity of C-2 products (FEC2 = 85.5 % at -1.38 V vs RHE). Besides, an energy-savings and economic electrolyzer can be achieved by coupling anodic BA oxidation reaction to benzoic acid and ECO2RR to C-2 products with much lowered cell voltages.

We investigate the expansion dynamics of spin-orbit-coupled Bose-Einstein condensates subjected to a synthetic magnetic field, after their release from an external harmonic trap. Our findings reveal that the condensate experiences a spin-dependent rotation and separation due to the rigid-like rotational velocity field, which leads to a spin density deflection. The deflection angle reaches a peak at a time that is inversely related to the frequency of the harmonic trap. When the detuning gradient is below a critical value for vortex nucleation, our analytical results derived from a spinor hydrodynamic theory align closely with numerical results using the coupled Gross-Pitaevskii equations. Beyond this critical value, we also numerically simulated the expansion dynamics of the condensates containing vortices with negative circulation. Our findings highlight the pivotal role of the rigid-like rotational velocity field on the dynamics of the condensate and may stimulate further experimental investigations into the rich superfluid dynamics induced by synthetic magnetic fields.

A honeycomb-like PtAu alloy catalyst has been developed to modulate the adsorption capacity of OH − species and adsorption configuration of glycerol on the catalyst surface for electrocatalytic glycerol upgrading of C 3 chemicals.

The quantum walk of two hard-core bosons in one-dimensional lattice under the effect of long-range inter-particle interaction is studied in detail. We also simulate the influence of an isolated defect that may exist in the lattice on the quantum walk of two particles by adding an additional potential energy to a certain lattice site. Using exact diagonalization method, the continuous-time quantum walk is directly simulated. The numerical simulations show that the range of interaction (long-range or short-range), the strength of the inter-particle interaction, the initial state of the two particles and the presence of the isolated defect have great influences on the quantum walk. Under the effect of strong long-range interaction, the particles initially located on the non-adjacent lattice sites have a co-walking behavior, while under the short-range interactions (nearest-neighbor interactions) only two particles initially located on the neighboring lattice sites can exhibit co-walking. After introducing the isolated defect into the system with strong interaction, two particles residing on the same side of the isolated defect keep co-walking, while two particles located on either sides of the isolated defect or one particle located on the isolated defect and the other particle staying on the side of the isolated defect, the two particles keep stationary or co-walking near the defect, displaying the characteristics of localization. By using the second-order perturbation theory of degenerate quantum system, a comprehensive theoretical analysis of the above numerical results is given. The theoretical analysis reveals the underlying physical law of quantum walks of two particles in one-dimensional lattice under the effects of strong long-range interaction and isolated defect in the lattice.

We study ground states of attractive Bose gases, which are confined in a harmonic trap V(x)=x_1^2+Λ x_2^2 ( Λ≥ 1 ) rotating at the velocity Ω . For any 0≤Ω <Ω ^*:=2 , where Ω ^* is called a critical rotational velocity, it is well known that ground states exist if and only if a0 denotes the product for the number of particles times the absolute value of the scattering length. In this paper, we consider the critical rotating case, where the rotational velocity Ω =Ω ^* , to study the existence and non-existence of ground states with respect to a>0 . As imposed in Remark 2.2 of Lewin et al. (Blow-up profile of rotating 2D focusing bose gases. macroscopic limits of quantum systems, Springer, Berlin, 2018), we also analyze the limiting behavior of ground states as a↗ a^* for the case where Ω =Ω _a:=Ω ^*√(1-C_0(a^*-a)^m)↗Ω ^* , 0≤ m<1/2 and 0

Chiral metasurfaces, with appealing properties for studying light-matter interactions at the nanoscale, have emerged as a promising platform for the realization of chiral optical responses, thereby showing advantages in chirality-related applications. The conventional approaches primarily concentrate on circular dichroism and the high Q factor of the chiral resonances, while little attention has been paid to the aspects of flexibility and controllability in the modulation of optical chirality, further inhibiting the implementation of tunable and multifunctional chiral metadevices. Here, we employ a planar chiral silicon metasurface governed by bound states in the continuum (BICs) to unravel steerable chiral optical responses. In particular, the BIC-based intrinsic and extrinsic planar chiralities can be precisely steered by breaking the in-plane symmetry and the illumination symmetry, respectively. Moreover, a hybrid Si-VO2 metasurface, manifested by the chiral coupled-mode theory, showcases the feasibility of actively tuning the dissipative loss while maintaining chiral quasi-BICs, then yielding desired loss-steered optical chirality. Our results provide alternative insights into tunable optical chirality and pave the way for advancements in chiroptical applications.

Medical image segmentation is an important field in medical image analysis and a vital part of computer -aided diagnosis. Due to the challenges in acquiring image annotations, semi-supervised learning has attracted high attention in medical image segmentation. Despite their impressive performance, most existing semi -supervised approaches lack attention to ambiguous regions (e.g., some edges or corners around the organs). To achieve better performance, we propose a novel semi-supervised method called Adaptive Loss Balancing based on Homoscedastic Uncertainty in Multi-task Medical Image Segmentation Network (AHU-MultiNet). This model contains the main task for segmentation, one auxiliary task for signed distance, and another auxiliary task for contour detection. Our multi-task approach can effectively and sufficiently extract the semantic information of medical images by auxiliary tasks. Simultaneously, we introduce an inter-task consistency to explore the underlying information of the images and regularize the predictions in the right direction. More importantly, we notice and analyze that searching an optimal weighting manually to balance each task is a difficult and time-consuming process. Therefore, we introduce an adaptive loss balancing strategy based on homoscedastic uncertainty. Experimental results show that the two auxiliary tasks explicitly enforce shape -priors on the segmentation output to further generate more accurate masks under the adaptive loss balancing strategy. On several standard benchmarks, the 2018 Atrial Segmentation Challenge and the 2017 Liver Tumor Segmentation Challenge, our proposed method achieves improvements and outperforms the new state-of-the-art in semi-supervised learning.

MedMNIST is a medical dataset proposed to block the need for medical knowledge, but there is currently no model that can generalize well on all its sub-datasets. Owing to the inadequacy of long-range relation modeling, models based on convolutional neural networks (CNNs) cannot fully learn the information of images. Besides, relying only on high-level features limits the generalization effect as well. All of these remain challenges for MedMNIST Classification Decathlon. In this paper, we proposed Feature Pyramid Vision Transformer (FPViT), a strong alternative for MedMNIST Classification Decathlon. Our FPViT exhibits enhanced feature learning and modeling capabilities, which merits both residual network (ResNet) and Vision Transformer (ViT). Transformers in our model take the features extracted by ResNet as sequences to capture global contexts which compensate for the lack of locality of convolution operations. Moreover, the feature pyramid designed in our model effectively utilizes the multi-scale feature maps from basic layers of ResNet. These multi-scale features from low-level to high level enable our model to have better adaptability. And, the final prediction is based on the multi-scale ViT and the original ResNet heads. Through experiments, our FPViT can achieve superior classification and generalization on MedMNIST than state-of-the-art methods.

Imporving the generalization ability of an agent is an important and challenging task in deep reinforcement learning (RL). Procedually generated environment is an important benchmark for testing generalization in deep RL. In this benchmark, each game consists of multiple levels, each level is an algorithmically created environment instance with a unique configuration of its factors of variation. Existing methods (e.g., regularization, data augmentation) for improving the generalization of RL agent do not learn well the invariant representation among multiple levels. Besides, existing methods for learning invariant representations in RL using adversarial training can only learn invariant information across two levels. To solve this problem, we propose Adversarial Discriminative Feature Separate (ADFS). First, ADFS design a new discriminator for distinguishing whether two observations belong to the same level. Thus, the policy encoder is encouraged to learn invariant information between multiple levels. Second, it separates the representation of observation into level-invariant features and level-discriminative features, so that correction of the optimization direction of the discriminator. The discriminative features are learned by reducing the similarity of specific features intra-levels and increasing that of inter-levels, respectively. Experimental results demonstrate that our method is quite competitive with existing state-of-the-art methods on Procgen Benchmark.

The commercialization of nickel-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) has been hindered by its continuous loss of practical capacity and reduction in average working voltage. To address these issues, surface modification has been well-recognized as an effective strategy. Different from the coatings reported in literature to date, in this work, we for the first time report a sulfide coating, amorphous Li2S via atomic layer deposition (ALD). Our study revealed that the conformal nano-Li2S coating shows exceptional protection over the NMC811 cathodes, accounting for the dramatically boosted capacity retention from similar to 11.6% to similar to 71% and the evidently mitigated voltage reduction from 0.39 to 0.18 V after 500 charge-discharge cycles. In addition, the Li2S coating remarkably improved the rate capability of the NMC811 cathode. Our investigation further revealed that all these beneficial effects of the ALD-deposited nano-Li2S coating lie in the following aspects: (i) maintain the mechanical integrity of the NMC811 electrode; (ii) stabilize the NMC electrode/electrolyte interface; and (iii) suppress the irreversible phase transition of NMC structure. Particularly, this study also has revealed that the nano-Li2S coating has played some unique role not associated with traditional non-sulfide coatings such as oxides. In this regard, we disclosed that the Li2S layer has reacted with the released O-2 from the NMC lattices, and thereby has dramatically mitigated electrolyte oxidation and electrode corrosion. Thus, this study is significant and has demonstrated that sulfides may be an important class of coating materials to tackle the issues of NMCs and other layered cathodes in lithium batteries. (C) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

In recent years, quantifying non-Markovian effect in open quantum system has become an important subject in the quantum decoherence control field. In this paper, a non-Markovian measure independent of the initial state of open system is proposed, thereby extending non-Markovian measure based on quantum Fisher information from the case where the initial state of the system is a pure state to the case where the initial state of the system is an arbitrary mixed state. As its application, the non-Markovian process is quantified by quantum Fisher information about a two-level system undergoing the three well-known dissipative channels, i.e. amplitude dissipative channel, phase damping channel, and random unitary channel. The results show that the conditions of non-Markovian processes in the three dissipative channels are independent of the selection of the initial state of the system by means of the quantum Fisher information of a phase parameter. Further, for amplitude dissipation channel and phase damping channel, the conditions for the non-Markovian processes to occur are equivalent to those given by trace distance, divisibility, quantum mutual information, quantum Fisher-information matrix, et al. As expected, for the case of amplitude dissipation channel, the corresponding results can reduce to the one in other paper (Lu X M, Wang X G, Sun C P 2010 Phys. Rev. A 82 042103) by selecting the initial state of the system as an optimal pure state. However, for random unitary channel, the conditions of non-Markovian process are not equivalent to those for other measures. In addition, we also obtain an interesting relationship between quantum Fisher information and quantum coherence of the open system in the three dissipative channels, namely the square of quantum \begin{document}$l_1$\end{document} coherence for the evolved state of system is exactly equal to the quantum Fisher information of the phase parameter. In a word, the obtained results not only improve the application scope of using the quantum Fisher information to detect non-Markovian effects in open systems, but also further highlight its important role in quantum information processing.