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The quantum charge-coupled device (QCCD) is one of the notable architectures to achieve large-scale trapped-ion quantum computers. To realize QCCD architecture, ions must be transported quickly while minimizing motional excitation. High-voltage sources are necessary to achieve such high-quality ion transport through a high secular frequency. In this study, we report the development of an FPGA-based DAC system with an output voltage range of +/-50 V and demonstrate its effectiveness in ion transport operations. By optimizing the voltage sets for ion transport, we experimentally confirm that the developed DAC system, when operated with an output range of +/- 50 V, achieves more than twice the secular frequency attainable when its output range is restricted to +/-10 V, a limit commonly associated with conventional DACs. The developed DAC system has good potential to enable fast ion transport with minimal motional excitation, thereby reducing processing times in QCCD-based quantum computers., Comment: 7 pages, 9 figures

Mistake action detection from egocentric videos is crucial for developing intelligent archives that detect workers' errors and provide feedback. Previous studies have been limited to specific domains, focused on detecting mistakes from videos without procedural texts, and analyzed whether actions are mistakes. To address these limitations, in this paper, we propose the EgoOops dataset, which includes egocentric videos, procedural texts, and three types of annotations: video-text alignment, mistake labels, and descriptions for mistakes. EgoOops covers five procedural domains and includes 50 egocentric videos. The video-text alignment allows the model to detect mistakes based on both videos and procedural texts. The mistake labels and descriptions enable detailed analysis of real-world mistakes. Based on EgoOops, we tackle two tasks: video-text alignment and mistake detection. For video-text alignment, we enhance the recent StepFormer model with an additional loss for fine-tuning. Based on the alignment results, we propose a multi-modal classifier to predict mistake labels. In our experiments, the proposed methods achieve higher performance than the baselines. In addition, our ablation study demonstrates the effectiveness of combining videos and texts. We will release the dataset and codes upon publication.

Magnon dynamics in quantum magnetism have long sparked interest in condensed matter physics. Since Bethe's prediction nearly a century ago, multimagnon bound states have presented significant potential for both fundamental insights and technological applications. Despite this, observing these bound states in natural materials has been challenging, partly due to the prevailing view that high magnetic fields are necessary for their stabilization. Here, we demonstrate that low-dimensional spin systems, specifically quasi-one-dimensional edge-shared cuprates, offer a promising landscape for realizing multimagnon bound states through a novel stabilization mechanism. This approach leverages small antiferromagnetic interchain couplings that act as effective internal magnetic fields, promoting collinear antiferromagnetic order and fostering self-organized magnon condensation at lower field strengths. By circumventing the need for high external fields, this mechanism provides a more experimentally accessible pathway, with implications for developing magnon-based quantum computing architectures, low-power spintronic devices, and high-speed magnonic circuits for efficient information processing. Our study presents a theoretical framework, supported by numerical simulations and experimental data from quasi-one-dimensional cuprates such as Li$_2$CuO$_2$, Ca$_2$Y$_2$Cu$_5$O$_{10}$, LiCuSbO$_4$, and PbCuSO$_4$(OH)$_2$. Beyond practical applications, our findings reveal that small interchain couplings can induce previously unobserved magnetic phenomena, offering new insights into the nature of magnetic ordered states., Comment: 20 pages, 5 figues, Supplementary information

We study the ground state properties of antiferromagnetic $J_1$-$J_2$ chains with half-integer spins ranging from $S=\frac{3}{2}$ to $S=\frac{11}{2}$ using the density-matrix renormalization group method. We map out the ground-state phase diagrams as a function of $\frac{J_2}{J_1}$ containing topological phases with alternating $\frac{2S-1}{2}$ and $\frac{2S+1}{2}$ valence bonds. We identify these topological phases and their boundaries by calculating the string order parameter, the dimer order parameter, and the spin gap for those high-$S$ systems in thermodynamic limit (finite size scaling). We find that these topological regions narrow down inversely with $S$ and converge to a single point at $\frac{J_2}{J_1}=\frac{1}{4}$ in the classical limit -- a critical threshold between commensurate and incommensurate orders. In addition, we extend the discussion of the Majumder-Ghosh state, previously noted only for $S=\frac{1}{2}$, and speculate its possible presence as a ground state in half-integer high spin systems over a substantial range of $\frac{J_2}{J_1}$ values., Comment: 6 pages, 4 figures, Supplementary Material

A range of honeycomb Co oxide compounds has been proposed and investigated in the search for a topological Kitaev spin liquid. Analyzing the quantum chemistry of interacting magnetic moments in Na$_3$Co$_2$SbO$_6$, a representative $LS$-coupled $t_{2g}^5e_g^2$ magnet, we find that the Kitaev and off-diagonal $\Gamma$ interactions are sizable and antiferromagnetic but still weaker than the Heisenberg contribution. Except $\Gamma$', all nearest-neighbor couplings are mainly determined by Coulomb exchange, different from current representations of anisotropic interaction terms. This highlights the limitations of existing anisotropic models and the need for systematic wave-function quantum chemical studies to clarify exchange mechanisms in Kitaev-Heisenberg systems.

Big data, encompassing extensive datasets, has seen rapid expansion, notably with a considerable portion being textual data, including strings and texts. Simple compression methods and standard data structures prove inadequate for processing these datasets, as they require decompression for usage or consume extensive memory resources. Consequently, this motivation has led to the development of compressed data structures that support various queries for a given string, typically operating in polylogarithmic time and utilizing compressed space proportional to the string's length. Notably, the suffix array (SA) query is a critical component in implementing a suffix tree, which has a broad spectrum of applications. A line of research has been conducted on (especially, static) compressed data structures that support the SA query. A common finding from most of the studies is the suboptimal space efficiency of existing compressed data structures. Kociumaka, Navarro, and Prezza [IEEE Trans. Inf. Theory 2023] have made a significant contribution by introducing an asymptotically minimal space requirement, $O\left(\delta \log\frac{n\log\sigma}{\delta\log n} \log n \right)$ bits ($\delta$-optimal space), sufficient to represent any string of length $n$, with an alphabet size of $\sigma$, and substring complexity $\delta$, serving as a measure of repetitiveness. More recently, Kempa and Kociumaka [FOCS 2023] presented $\delta$-SA, a compressed data structure supporting SA queries in $\delta$-optimal space. However, the data structures introduced thus far are static. We present the first dynamic compressed data structure that supports the SA query and update in polylogarithmic time and $\delta$-optimal space. More precisely, it can answer SA queries and perform updates in $O(\log^7 n)$ and expected $O(\log^8 n)$ time, respectively, using an expected $\delta$-optimal space., Comment: Abstract shortened to fit ArXiv requirements

We present a detailed investigation of the XXZ Heisenberg model for spin-$1/2$ and spin-$1$ systems on square and honeycomb lattices. Utilizing the density-matrix renormalization group (DMRG) method, complemented by Spiral Boundary Conditions (SBC) for mapping two-dimensional (2D) clusters onto one-dimensional (1D) chains, we meticulously explore the evolution of staggered magnetization and spin gaps across a broad spectrum of easy-axis anisotropies. Our study reveals that, despite the lower site coordination number of honeycomb lattice, which intuitively suggests increased quantum fluctuations in its N\'eel phase compared to the square lattice, the staggered magnetization in the honeycomb structure exhibits only a marginal reduction. Furthermore, our analysis demonstrates that the dependence of staggered magnetization on the XXZ anisotropy $\Delta$, except in close proximity to $\Delta=1$, aligns with series expansion predictions up to the 12th order. Notably, for the $S=1/2$ honeycomb lattice, deviations from the 10th order series expansion predictions near the isotropic Heisenberg limit emphasize the critical influence of quantum fluctuations on the spin excitation in its N\'eel state. Additionally, our findings are numerically consistent with the singular behavior of the spin gap near the isotropic Heisenberg limit as forecasted by spin-wave theory. The successful implementation of SBC marks a methodological advancement, streamlining the computational complexity involved in analyzing 2D models and paving the way for more precise determinations of physical properties in complex lattice systems., Comment: 11 pages, 10 figures, 3 tables

Motivated by the largely unexplored domain of multi-polar ordered spin states in the Kitaev-Heisenberg (KH) systems we investigate the ground state dynamics of the spin-$\frac{1}{2}$ KH model, focusing on quadrupolar (QP) order in 2-leg ladder and two-dimensional honeycomb lattice geometries. Employing exact diagonalization and density-matrix renormalization group methods, we analyze the QP order parameter and correlation functions. Our findings reveal a robust QP order across a wide range of the phase diagram, influenced by the interplay between Heisenberg and Kitaev interactions. Notably, we observe an enhancement of QP order near Kitaev quantum spin liquid (QSL) phases, despite the absence of long-range spin-spin correlations. This highlights a complex relationship between QP order and QSLs, offering new insights into quantum magnetism in low-dimensional systems. Our findings provide a rational explanation for the observed nonlinear magnetic susceptibility in $\alpha$-RuCl$_3$.

The search for Kitaev spin liquid states has recently broadened to include a number of honeycomb materials with integer spin moments. The qualitative difference with their spin-1/2 counterparts is the presence of single-ion anisotropy (SIA). This motivates our investigation of the effects of SIA on the ground state of the spin-$1$ Kitaev-Heisenberg (KH) model using the density-matrix renormalization group which allows construction of detailed phase diagrams around the Kitaev points. We demonstrate that positive out-of-plane SIA induces an in-plane vortex state without the need for off-diagonal interactions. Conversely, negative SIA facilitates the emergence of a ferromagnetic state in presence of antiferromagnetic Heisenberg interactions, while a N\`eel state can emerge for ferromagnetic Heisenberg coupling. These findings, pertinent even for weak SIA, not only enhance our theoretical understanding of the spin-1 KH model but also propose experimental prospects for observing these novel magnetic states in material realizations.