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A novel oxychloride, Sr$_{3}$Ni$_{2}$O$_{5}$Cl$_{2}$, was synthesized for the first time under high pressure of 10 GPa at 1400 ${}^\circ$C, motivated by a theoretical prediction of its potential superconductivity under ambient pressure. Small single crystals were used to determine the crystal structure and measure the temperature dependence of electrical resistance. The crystal is isostructural with the recently discovered superconductor, La$_{3}$Ni$_{2}$O$_{7}$, in line with the theoretical expectation.

The potential of Wi-Fi backscatter communications systems is immense, yet challenges such as signal instability and energy constraints impose performance limits. This paper introduces FlexScatter, a Wi-Fi backscatter system using a designed scheduling strategy based on excitation prediction and rateless coding to enhance system performance. Initially, a Wi-Fi traffic prediction model is constructed by analyzing the variability of the excitation source. Then, an adaptive transmission scheduling algorithm is proposed to address the low energy consumption demands of backscatter tags, adjusting the transmission strategy according to predictive analytics and taming channel conditions. Furthermore, leveraging the benefits of low-density parity-check (LDPC) and fountain codes, a novel coding and decoding algorithm is developed, which is tailored for dynamic channel conditions. Experimental validation shows that FlexScatter reduces bit error rates (BER) by up to 30%, improves energy efficiency by 7%, and increases overall system utility by 11%, compared to conventional methods. FlexScatter's ability to balance energy consumption and communication efficiency makes it a robust solution for future IoT applications that rely on unpredictable Wi-Fi traffic.

A travel groupoid is an algebraic system satisfying two suitable conditions, which has a relation to graphs. In this article, we characterize travel groupoids on finite complete multipartite graphs, and we give the numbers of travel groupoids on the complete multipartite graphs.

Micromagnet-enabled electric-dipole spin resonance (EDSR) is an established method of high-fidelity single-spin control in silicon. However, the resulting architectural limitations have restrained silicon quantum processors to one-dimensional arrays, and heating effects from the associated microwave dissipation exacerbates crosstalk during multi-qubit operations. In contrast, qubit control based on hopping spins has recently emerged as a compelling primitive for high-fidelity baseband control in sparse two-dimensional hole arrays in germanium. In this work, we commission a $^{28}$Si/SiGe 2x2 quantum dot array both as a four-qubit device with pairwise exchange interactions using established EDSR techniques and as a two-qubit device using baseband hopping control. In this manner, we can evaluate the two modes of operation in terms of fidelity, coherence, and crosstalk. We establish a lower bound on the fidelity of the hopping gate of 99.50(6)%, which is similar to the average fidelity of the resonant gate of 99.54(4)%. Lowering the external field to reach the hopping regime nearly doubles the measured $T_2^{\mathrm{H}}$, suggesting a reduced coupling to charge noise. Finally, the hopping gate circumvents the transient pulse-induced resonance shift. To further motivate the hopping gate approach as an attractive means of scaling silicon spin-qubit arrays, we propose an extensible nanomagnet design that enables engineered baseband control of large spin arrays., Comment: main text with 12 pages and 5 figures, methods and extended data and supplementary materials with 22 pages and 11 figures and 1 table, in a single file

Using the Subaru/FOCAS IFU capability, we examine the spatially resolved relationships between gas-phase metallicity, stellar mass, and star-formation rate surface densities (Sigma_* and Sigma_SFR, respectively) in extremely metal-poor galaxies (EMPGs) in the local universe. Our analysis includes 24 EMPGs, comprising 9,177 spaxels, which span a unique parameter space of local metallicity (12+log(O/H) = 6.9 to 7.9) and stellar mass surface density (Sigma_* ~ 10^5 to 10^7 Msun/kpc^2), extending beyond the range of existing large integral-field spectroscopic surveys. Through spatially resolved emission line diagnostics based on the [NII] BPT-diagram, we verify the absence of evolved active galactic nuclei in these EMPGs. Our findings reveal that, while the resolved mass-metallicity relation exhibits significant scatter in the low-mass regime, this scatter is closely correlated with local star-formation surface density. Specifically, metallicity decreases as Sigma_SFR increases for a given Sigma_*. Notably, half of the EMPGs show a distinct metal-poor horizontal branch on the resolved mass-metallicity relation. This feature typically appears at the peak clump with the highest Sigma_* and Sigma_SFR and is surrounded by a relatively metal-enriched ambient region. These findings support a scenario in which metal-poor gas infall fuels episodic star formation in EMPGs, consistent with the kinematic properties observed in these systems. In addition, we identify four EMPGs with exceptionally low central metallicities (12+log(O/H) <~ 7.2), which display only a metal-poor clump without a surrounding metal-rich region. This suggests that such ultra-low metallicity EMPGs, at less than a few percent of the solar metallicity, may serve as valuable analogs for galaxies in the early stages of galaxy evolution., Comment: 29 pages, 14 figures. Submitted to ApJ

The spontaneous breaking of CP symmetry in 4D SU($N$) pure Yang-Mills theory at $\theta=\pi$ has recently attracted much attention in the context of the higher-form symmetry and the 't Hooft anomaly matching condition. Here we use Monte Carlo simulations to study the $N=2$ case, which is interesting since it is the case opposite to the large-$N$ limit, where explicit calculations are available. In order to circumvent the severe sign problem due to the $\theta$ term for real $\theta$, we first obtain results at imaginary $\theta$, where the sign problem is absent, and make an analytic continuation to real $\theta$. We use the stout smearing in defining the $\theta$ term in the action to be used in our simulations. Thus we obtain the expectation value of the topological charge and the deconfining temperature at $\theta=\pi$, and provide an evidence that the CP symmetry, which is spontaneously broken at low temperature, gets restored \emph{strictly above} the deconfining temperature. This conclusion is consistent with the anomaly matching condition and yet differs from the prediction in the large-$N$ limit., Comment: 25 pages, 9 figures

This paper proposes an $O(N)$ fast direct solver for two-dimensional elastic wave scattering problems. The proxy surface method is extended to elastodynamics to obtain shared coefficients for low-rank approximations from discretized integral operators. The proposed method is a variant of the Martinsson-Rokhlin-type fast direct solver. Our variant avoids the explicit computation of the inverse of the coefficient matrix, thereby reducing the required number of matrix-matrix multiplications. Numerical experiments demonstrate that the proposed solver has a complexity of $O(N)$ in the low-frequency range and has a highly parallel computation efficiency with a strong scaling efficiency of 70\%. Furthermore, multiple right-hand sides can be solved efficiently; specifically, when solving problems with 180 right-hand side vectors, the processing time per vector from the second vector onward was approximately 28,900 times faster than that for the first vector. This is a key advantage of fast direct methods.

Objective: Direct cortical responses (DCR) and axono-cortical evoked potentials (ACEP) are generated by electrically stimulating the cortex either directly or indirectly through white matter pathways, potentially leading to different electrogenic processes. For ACEP, the slow conduction velocity of axons (median around 4 m.s$^{-1}$) is anticipated to induce a delay. For DCR, direct electrical stimulation (DES) of the cortex is expected to elicit additional cortical activity involving smaller and slower non-myelinated axons. We tried to validate these hypotheses. Methods: DES was administered either directly on the cortex or to white matter fascicles within the resection cavity, while recording DCR or ACEP at the cortical level in nine patients. Results: Short but significant delays (around 2 ms) were measurable for ACEP immediately following the initial component (around 7 ms). Subsequent activities (around 40 ms) exhibited notable differences between DCR and ACEP, suggesting the presence of additional cortical activities for DCR. Conclusion: Distinctions between ACEPs and DCRs can be made based on a delay at the onset of early components and the dissimilarity in the shape of the later components >40 ms after the DES artifact). Significance: The comparison of different types of evoked potentials allows to better understand the effects of DES., Comment: Clinical Neurophysiology, 2024

We present the luminosity functions (LFs) and angular correlation functions (ACFs) derived from 18,960 Ly$\alpha$ emitters (LAEs) at $z=2.2-7.3$ over a wide survey area of $\lesssim24 {\rm deg^2}$ that are identified in the narrowband data of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) and the Cosmic HydrOgen Reionization Unveiled with Subaru (CHORUS) surveys. Confirming the large sample with the 241 spectroscopically identified LAEs, we determine Ly$\alpha$ LFs and ACFs in the brighter luminosity range down to $0.5L_{\star}$, and confirm that our measurements are consistent with previous studies but offer significantly reduced statistical uncertainties. The improved precision of our ACFs allows us to clearly detect one-halo terms at some redshifts, and provides large-scale bias measurements that indicate hosting halo masses of $\sim 10^{11} M_\odot$ over $z\simeq 2-7$. By comparing our Ly$\alpha$ LF (ACF) measurements with reionization models, we estimate the neutral hydrogen fractions in the intergalactic medium to be $x_{\rm \HI}<0.05$ (=${0.06}^{+0.12}_{-0.03}$), $0.15^{+0.10}_{-0.08}$ (${0.21}^{+0.19}_{-0.14}$), $0.18^{+0.14}_{-0.12}$, and $0.75^{+0.09}_{-0.13}$ at $z=5.7$, $6.6$, $7.0$, and $7.3$, respectively. Our findings suggest that the neutral hydrogen fraction remains relatively low, $x_{\rm \HI} \lesssim 0.2$, at $z=5-7$, but increases sharply at $z > 7$, reaching $x_{\rm \HI} \sim 0.9$ by $z \simeq 8-9$, as indicated by recent JWST studies. The combination of our results from LAE observations with recent JWST observations suggests that the major epoch of reionization occurred around $z \sim 7-8$, likely driven by the emergence of massive sources emitting significant ionizing photons., Comment: Submitted to ApJS

We investigate the magnetic ground state of single crystals of the ruthenium-dimer-based hexagonal perovskite Ba$_{3}$ZnRu$_{2}$O$_{9}$ using magnetic susceptibility and resonant inelastic x-ray scattering (RIXS) measurements. While a previous study on powder samples exhibited intriguing magnetic behavior, questions about whether the spin state within a Ru$_{2}$O$_{9}$ dimer is a conventional $S = 3/2$ dimer or an orbital-selective $S = 1$ dimer were raised. The RIXS spectra reveal magnetic excitations from Hund's intraionic multiplet and intradimer spin-triplet transitions. The observed transition energies of the Hund's intraionic multiplets align with the $S=3/2$ ground state, contrasting with the theoretically proposed orbital-selective $S=1$ dimer state. High-temperature magnetic susceptibility analysis confirms the realization of the spin $S=3/2$ dimer state, and the extracted intradimer coupling is consistent with the spin-triplet transition energy observed in the RIXS spectra. These results highlights the ability of "spectroscopic fingerprinting" by RIXS to determine the magnetic ground states of complex materials.

This paper proposes a Bayesian method for estimating the parameters of a normal distribution when only limited summary statistics (sample mean, minimum, maximum, and sample size) are available. To estimate the parameters of a normal distribution, we introduce a data augmentation approach using the Gibbs sampler, where intermediate values are treated as missing values and samples from a truncated normal distribution conditional on the observed sample mean, minimum, and maximum values. Through simulation studies, we demonstrate that our method achieves estimation accuracy comparable to theoretical expectations.

Injection process of pickup ion acceleration at a heliospheric termination shock is investigated. Using two-dimensional fully kinetic particle-in-cell simulation, accelerated pickup ions are self-consistently reproduced by tracking long time evolution of shock with unprecedentedly large system size in the shock normal direction. Reflected pickup ions drive upstream large amplitude waves through resonant instabilities. Convection of the large amplitude waves causes shock surface reformation and alters the downstream electromagnetic structure. A part of pickup ions are accelerated to tens of upstream flow energy in the time scale of $\sim 100$ times inverse ion gyro frequency. The initial acceleration occurs through shock surfing acceleration mechanism followed by shock drift acceleration mechanism. Large electrostatic potential accompanied by the upstream waves enables the shock surfing acceleration to occur., Comment: 8 pages, 6 figures

The emergence of a second dome in the superconducting phase through pressure-driven manipulation of crystal structures in materials has attracted considerable attention. Transition metal chalcogenides (TMCs) represent a highly promising platform, as the second dome has been observed in several binary compounds. Recently, ternary TMCs such as Ta$_2$PdS$_6$ and Ta$_2$PdSe$_6$ have exhibited pressure-induced superconducting domes. In this study, we perform electrical transport measurements of Ta$_2$PdS$_6$ and Ta$_2$PdSe$_6$ under extremely high pressures exceeding 100 GPa, namely uninvestigated regions in previous reports, to reveal the emergence of the second dome. The superconducting critical temperatures (T$_c$) in both Ta$_2$PdS$_6$ and Ta$_2$PdSe$_6$ initially decrease with increasing pressure. Subsequently, the Tcs tend to enhance drastically above 100 GPa. Notably, the maximum T$_c$ in Ta$_2$PdS$_6$ is 11.2 K at 130.0 GPa, which is a relatively high record among the TMCs. The emergence of the second dome in Ta$_2$PdS$_6$ and Ta$_2$PdSe$_6$ opens further motivation for the investigation under extreme conditions beyond the first dome to find hidden ordered phases.

Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the twisting jet model presented in previous works to explain the multi-wavelength behaviour of BL Lacertae, the prototype of one of the blazar classes. According to this model, the jet is inhomogeneous, curved, and twisting, and the long-term variability is due to changes in the Doppler factor due to variations in the orientation of the jet-emitting regions. We analysed optical data of the source obtained during monitoring campaigns organised by the Whole Earth Blazar Telescope (WEBT) in 2019-2022, together with radio data from the WEBT and other teams, and gamma-ray data from the Fermi satellite. In this period, BL Lacertae underwent an extraordinary activity phase, reaching its historical optical and gamma-ray brightness maxima. The application of the twisting jet model to the source light curves allows us to infer the wiggling motion of the optical, radio, and gamma-ray jet-emitting regions. The optical-radio correlation shows that the changes in the radio viewing angle follow those in the optical viewing angle by about 120 days, and it suggests that the jet is composed of plasma filaments, which is in agreement with some radio high-resolution observations of other sources. The gamma-ray emitting region is found to be co-spatial with the optical one, and the analysis of the gamma-optical correlation is consistent with both the geometric interpretation and a synchrotron self-Compton (SSC) origin of the high-energy photons. We propose a geometric scenario where the jet is made up of a pair of emitting plasma filaments in a sort of double-helix curved rotating structure, whose wiggling motion produces changes in the Doppler beaming and can thus explain the observed multi-wavelength long-term variability., Comment: In press for A&A

Powerful, galactic outflows driven by Active Galactic Nuclei (AGNs) are commonly considered as a main mechanism to regulate star formation in massive galaxies. Ultra- and hyper-luminous IR galaxies (U/HyLIRGs) are thought to represent a transition phase of galaxies from a rapidly growing period to a quiescent status as gas swept out by outflows, providing a laboratory to investigate outflows and their feedback effects on the hosts. In this paper we report recent Gemini and ALMA observations of a HyLIRG, J1126 at $z=0.46842$, which has been identified with a puzzling co-existence of a fast ionized outflow ($>2000$ km s$^{-1}$) and an intense starburst (star formation rate of 800 $M_{\odot}$ yr$^{-1}$). The Gemini observation shows the fast ionized outflow is extended to several kpc with a mass-loss rate of 180 $M_{\odot}$ yr$^{-1}$. A massive molecular outflow with a high mass-loss rate (2500 $M_{\odot}$ yr$^{-1}$) is revealed by ALMA. The multi-phase outflows show large factors of momentum boost and loading of kinetic power, indicating a driving by thermal pressure of a nuclear hot wind and/or radiation pressure of a highly obscured AGN. In addition to ejection of kinetic energy, it is also found that the powerful outflow can induce an ionizing shock in the galaxy disk and enhance the excitation and dissociation of molecular gas. The powerful outflow probably results in an instantaneous negative feedback and shows potential to regulate the host growth in a long term., Comment: 35 pages, 26 figures, accepted to be published in ApJ

We study the importance of several processes that influence the evolution of dust and its grain size distribution on spatially resolved scales in nearby galaxies. Here, we compiled several multi-wavelength observations for the nearby galaxies NGC628(M74), NGC5457(M101), NGC598(M33), and NGC300. We applied spatially resolved spectral energy distribution fitting to the latest iteration of infrared data to get constraints on the galaxy dust masses and the small-to-large grain abundance ratio. For comparison, we took the radial profiles of the stellar mass and gas mass surface density for NGC628 combined with its metallicity gradient in the literature to calibrate a single-galaxy simulation using the GADGET4-OSAKA code. The simulations include a parametrization to separate the dense and diffuse phases of the ISM where different dust-evolution mechanisms are in action. We find that our simulation can reproduce the radial profile of dust mass surface density but overestimates the SLR in NGC628. Changing the dust-accretion timescale has little impact on the dust mass or SLR, as most of the available metals are accreted onto dust grains at early times (< 3Gyr), except in the outer regions of the galaxy. This suggests we can only constrain the accretion timescale of galaxies at extremely low metallicities where accretion still competes with other mechanisms controlling the dust budget. The overestimation of the SLR likely results from (i) overly efficient shattering processes in the diffuse interstellar medium, which were calibrated to reproduce Milky Way-type galaxies and/or (ii) our use of a diffuse and dense gas density subgrid model that does not entirely capture the intricacies of the small-scale structure present in NGC628., Comment: Accepted on October 12th 2024 16 pages, 13 figures

We explore the problem of distributed Hypothesis Testing (DHT) against independence, focusing specifically on Binary Symmetric Sources (BSS). Our investigation aims to characterize the optimal quantizer among binary linear codes, with the objective of identifying optimal error probabilities under the Neyman-Pearson (NP) criterion for short code-length regime. We define optimality as the direct minimization of analytical expressions of error probabilities using an alternating optimization (AO) algorithm. Additionally, we provide lower and upper bounds on error probabilities, leading to the derivation of error exponents applicable to large code-length regime. Numerical results are presented to demonstrate that, with the proposed algorithm, binary linear codes with an optimal covering radius perform near-optimally for the independence test in DHT., Comment: 10 pages, 3 figures, 1 pseudo code, 1 table, ITW 2024, accepted to be presented

Recent high-cadence transient surveys have discovered rapid transients whose light curve timescales are shorter than those of typical supernovae. In this paper, we present a systematic search for rapid transients at medium-high redshifts among 3381 supernova candidates obtained from the Subaru HSC-SSP transient survey. We developed a machine learning classifier to classify the supernova candidates into four types (Type Ia, Ibc, II supernovae, and rapid transients) based on the features derived from the light curves. By applying this classifier to the 3381 supernova candidates and by further applying the quality cut, we selected 14 rapid transient samples. They are located at a wide range of redshifts ($0.34 \leq z \leq 1.85$) and show a wide range of the peak absolute magnitude ($-17 \geq M \geq -22$). The event rate of the rapid transients is estimated to be $\sim 6\times10^3~\rm{events~yr^{-1}~Gpc^{-3}}$ at $z \sim 0.74$, which corresponds to about $2$ $\%$ of the event rate of normal core-collapse supernovae at the similar redshift. Based on the luminosity and color evolution, we selected two candidates of Type Ibn supernovae at $z\sim0.75$. The event rate of Type Ibn SN candidates is more than 1 $\%$ of Type Ib SN rate at the same redshift, suggesting that this fraction of massive stars at this redshift range eruptively ejects their He-rich envelope just before the explosions. Also, two objects at $z=1.37$ and 1.85 show high luminosities comparable to superluminous supernovae. Their event rate is about 10-25 $\%$ of superluminous supernovae at $z\sim 2$., Comment: 17 pages, 13 figures, accepted for publication in ApJ

We performed transverse-field muon spin relaxation/rotation (TF-{\mu}SR) on a high-entropy-type (HE-type) superconductor AgInSnPbBiTe5. The emergence of bulk superconducting states was confirmed from magnetic susceptibility, specific heat, and {\mu}SR. The superconducting gap 2{\Delta}(0) estimated from {\mu}SR was clearly larger than that expected from conventional weak-coupling phonon-mediated model, suggesting the strong-coupling nature of superconductivity. In addition, a long penetration depth of 3.21(7) {\mu}m was obtained. The strong-coupling nature of superconductivity and the long penetration depth are similar to the trends observed in the other HE-type superconductors (HE alloys and transition-metal zirconides), which may be universal feature of HE-type superconductors., Comment: 14 pages, 4 figures, Supplementary information

Determining the inner structure of the molecular torus around an active galactic nucleus is essential for understanding its formation mechanism. However, spatially resolving the torus is difficult because of its small size. To probe the clump conditions in the torus, we therefore perform the systematic velocity-decomposition analyses of the gaseous CO rovibrational absorption lines ($v=0\to 1,\Delta J=\pm 1$) at $\lambda\sim 4.67 \mathrm{\mu{m}}$ observed toward four (ultra)luminous infrared galaxies using the high-resolution ($R\sim 5000\text{--}10000$) spectroscopy from the Subaru Telescope. We find that each transition has two to five distinct velocity components with different line-of-sight (LOS) velocities ($V_\mathrm{LOS}\sim -240\text{--}+100\mathrm{km\,s^{-1}}$) and dispersions ($\sigma_V\sim 15\text{--}190\mathrm{km\,s^{-1}}$); i.e., the components (a), (b), ..., beginning with the broadest one in each target, indicating that the tori have clumpy structures. By assuming a hydrostatic disk ($\sigma_V\propto R_\mathrm{rot}^{-0.5}$), we find that the tori have dynamic inner structures, with the innermost component (a) outflowing with velocity $|V_\mathrm{LOS}|\sim 160\text{--}240\mathrm{km\,s^{-1}}$, and the outer components (b) and (c) outflowing more slowly or infalling with $|V_\mathrm{LOS}|\lesssim 100\mathrm{km\,s^{-1}}$. In addition, we find that the innermost component (a) can be attributed to collisionally excited hot ($\gtrsim 530$K) and dense ($n_\mathrm{H_2}\gtrsim 10^6\mathrm{cm^{-3}}$) clumps, based on the level populations. Conversely, the outer component (b) can be attributed to cold ($\sim 30\text{--}140$K) clumps radiatively excited by a far-infrared-to-submillimeter background with a brightness temperature higher than $\sim 20\text{--}400$K. These observational results demonstrate the clumpy and dynamic structure of tori in the presence of background radiation., Comment: 43 pages, 15 figures, accepted for publication in ApJ

Python is very popular because it can be used for a wider audience of developers, data scientists, machine learning experts and so on. Like other programming languages, there are beginner to advanced levels of writing Python code. However, like all software, code constantly needs to be maintained as bugs and the need for new features emerge. Although the Zen of Python states that "Simple is better than complex," we hypothesize that more elegant and proficient code might be harder for the developer to maintain. To study this relationship between the understanding of code maintainability and code proficiency, we present an exploratory study into the complexity of Python code on three Python libraries. Specifically, we investigate the risk level of proficient code inside a file. As a starting point, we mined and collected the proficiency of code from three PyPI libraries totaling 3,003 files. We identified several instances of high proficient code that was also high risk, with examples being simple list comprehensions, 'enumerate' calls, generator expressions, simple dictionary comprehensions, and the 'super' function. Our early examples revealed that most code-proficient development presented a low maintainability risk, yet there are some cases where proficient code is also risky to maintenance. We envision that the study should help developers identify scenarios where and when using proficient code might be detrimental to future code maintenance activities.

This paper provides an overview of the techniques employed by Hibikino-Musashi@Home, which intends to participate in the domestic standard platform league. The team has developed a dataset generator for training a robot vision system and an open-source development environment running on a Human Support Robot simulator. The large language model powered task planner selects appropriate primitive skills to perform the task requested by users. The team aims to design a home service robot that can assist humans in their homes and continuously attends competitions to evaluate and improve the developed system.

We investigate the mechanical behavior of jammed knitted fabrics, where geometric confinement leads to an initially stiff mechanical response that softens into low stiffness behavior with additional applied stress. We show that the jammed regime is distinguished by changes in yarn geometry and contact rearrangement that must occur to allow the individual stitches to stretch. These rearrangements allow for the relaxation of high residual contact forces that are present within jammed fabric, altering the low-strain response. We demonstrate that fabric jamming can be induced or reduced by changing either the constituent yarn or the fabric manufacturing parameters. Analysis of experimental samples shows that changing the "stitch size" in manufacturing affects both the in situ yarn radius and the length of yarn per stitch, both of which affect jamming., Comment: 12 pages main text, 6 figures, 14 page supplementary information, 15 supplementary figures

This paper analyzes the outage probability of orthogonal time frequency space (OTFS) modulation under a lossy communication scenario. First of all, we introduce the channel model and the vector form representation of OTFS this paper uses. Then, we derive an exact expression of the OTFS outage probability in lossy communication scenarios, using Shannon's lossy source-channel separation theorem. Because the channel is time-varying, calculating the exact outage probability is computationally expensive. Therefore, this paper aims to derive a lower bound of the outage probability, which can relatively easily be calculated. Thus, given the distortion requirement and number of the resolvable paths, we can obtain a performance limit under the optimal condition as a reference. Finally, the experimental results of outage probability are obtained by Monte-Carlo method, and compared with the theoretical results calculated by the closed-from expression of the lower bound.

In this paper, performance of a lossy cooperative unmanned aerial vehicle (UAV) relay communication system is analyzed. In this system, the UAV relay adopts lossy forward (LF) strategy and the receiver has certain distortion requirements for the received information. For the system described above, we first derive the achievable rate distortion region of the system. Then, on the basis of the region analysis, the system outage probability when the channel suffers Nakagami-$m$ fading is analyzed. Finally, we design an optimal relay position identification algorithm based on the Soft Actor-Critic (SAC) algorithm, which determines the optimal UAV position to minimize the outage probability. The simulation results show that the proposed algorithm can optimize the UAV position and reduce the system outage probability effectively.

The electron antinuetrino flux limits are presented for the brightest gamma-ray burst (GRB) of all time, GRB221009A, over a range of 1.8-200 MeV using the Kamioka Liquid Scintillator Anti Neutrino Detector (KamLAND). Using a variety of time windows to search for electron antineutrinos coincident with the GRB, we set an upper limit on the flux under the assumption of various neutrino source spectra. No excess was observed in any time windows ranging from seconds to days around the event trigger time. The limits are compared to the results presented by IceCube., Comment: 8 pages, 3 figures, 1 table

We have been developing an x-ray imaging system, Multi-Image X-ray Interferometer Module (MIXIM), to achieve a high angular resolution with a compact system size. MIXIM is comprised of a mask with equally-spaced apertures and an x-ray detector. The aperture size and mask-detector distance determine the system's angular resolution. Although a smaller aperture gives a better resolution, the degree of improvement is limited by a diffraction effect. MIXIM circumvents this problem by utilizing the Talbot effect. Our experiment with the previous model equipped with a multi-pinhole mask obtained an angular resolution of 0.5" with a mask-detector distance of 92 cm. A major downside of the multi-pinhole mask is, however, that it has a very low opening fraction, which results in a very low effective area. Here, we newly adopt to MIXIM a multiple coded aperture (MCA) mask, an array of coded aperture patterns. Our proof-of-concept experiment demonstrates that the Talbot effect works even for the MCA mask with a high opening fraction of ~50% at 12.4 keV. Consequently, the new MIXIM realizes about 25 times as large an effective area as that of the previous model, while maintaining a high angular resolution of 0.2" and a compact size of ~1.5 m., Comment: 27 pages, 11 figures, accepted for publication in JATIS

We investigate mappings $F = (f_1, f_2) \colon \mathbb{R}^2 \to \mathbb{R}^2 $ where $ f_1, f_2 $ are bivariate normal densities from the perspective of singularity theory of mappings, motivated by the need to understand properties of two-component bivariate normal mixtures. We show a classification of mappings $ F = (f_1, f_2) $ via $\mathcal{A}$-equivalence and characterize them using statistical notions. Our analysis reveals three distinct types, each with specific geometric properties. Furthermore, we determine the upper bounds for the number of modes in the mixture for each type., Comment: 12 page, 5 figures

Several heavy fermion materials, including UPt$_3$, exhibit a rapid but gradual rise in the magnetization at a critical field, without an apparent phase transition at any temperature $T>0$, with the possibility of a first order transition at $T \equiv0$. To model such a quantum phase transition it is most appropriate to develop approaches considering the quantum nature of the spins. Within a fully classical framework, we show that it is sufficient to start from a Landau-type free energy with an added Bragg-Williams entropy term to arrive at a number of key experimental features as seen in UPt$_3$. In particular, we show that correctly arriving at the measured (low-field) higher order susceptibilities necessarily invokes an isobestic (crossing) point at a high field in the magnetization isotherms. We also present a full analysis of the angular dependence of the (low-field) linear and nonlinear susceptibilities which when extended also capture the anisotropic high field response of the magnetization. Key to this success is the proper conversion of the evaluated magnetization from constant volume to a constant pressure situation relevant at high fields in heavy fermion materials., Comment: Main paper: 7 pages, 6 figures Supp info: 4 pages, 5 figures

Strong soft X-ray emission called soft X-ray excess is often observed in luminous active galactic nuclei (AGN). It has been suggested that the soft X-rays are emitted from a warm ($T=10^6\sim10^7\ \rm{K}$) region that is optically thick for the Thomson scattering (warm Comptonization region). Motivated by the recent observations that soft X-ray excess appears in changing look AGN (CLAGN) during the state transition from a dim state without broad emission lines to a bright state with broad emission lines, we performed global three-dimensional radiation magnetohydrodynamic simulations assuming that the mass accretion rate increases and becomes around $10$\% of the Eddington accretion rate. The simulation successfully reproduces a warm, Thomson-thick region outside the hot radiatively inefficient accretion flow near the black hole. The warm region is formed by efficient radiative cooling due to inverse Compton scattering. The calculated luminosity $0.01L_{{\rm Edd}}-0.08L_{{\rm Edd}}$ is consistent with the luminosity of CLAGN. We also found that the warm Comptonization region is well described by the steady model of magnetized disks supported by azimuthal magnetic fields. When the anti-parallel azimuthal magnetic fields supporting the radiatively cooled region reconnect around the equatorial plane of the disk, the temperature of the region becomes higher by releasing the magnetic energy transported to the region., Comment: Published in ApJ

We study the asymptotic behavior of a multiple series of Mordell-Tornheim type and its integral analogue at x=0. Our approach is to show a relation between the multiple series and its integral analogue by using Abel's summation formula, and to deeply investigate the behavior of the integral analogue. Additionally, we establish some nontrivial relations among multiple polylogarithms by comparing two seemingly different asymptotic formulas for the integral analogue., Comment: 30pages

A search for proton decay into $e^+/\mu^+$ and a $\eta$ meson has been performed using data from a 0.373 Mton$\cdot$year exposure (6050.3 live days) of Super-Kamiokande. Compared to previous searches this work introduces an improved model of the intranuclear $\eta$ interaction cross section, resulting in a factor of two reduction in uncertainties from this source and $\sim$10\% increase in signal efficiency. No significant data excess was found above the expected number of atmospheric neutrino background events resulting in no indication of proton decay into either mode. Lower limits on the proton partial lifetime of $1.4\times\mathrm{10^{34}~years}$ for $p\rightarrow e^+\eta$ and $7.3\times\mathrm{10^{33}~years}$ for $p\rightarrow \mu^+\eta$ at the 90$\%$ C.L. were set. These limits are around 1.5 times longer than our previous study and are the most stringent to date.

Large Language Models (LLMs) have taken the world by storm, demonstrating their ability not only to automate tedious tasks, but also to show some degree of proficiency in completing software engineering tasks. A key concern with LLMs is their "black-box" nature, which obscures their internal workings and could lead to societal biases in their outputs. In the software engineering context, in this early results paper, we empirically explore how well LLMs can automate recruitment tasks for a geographically diverse software team. We use OpenAI's ChatGPT to conduct an initial set of experiments using GitHub User Profiles from four regions to recruit a six-person software development team, analyzing a total of 3,657 profiles over a five-year period (2019-2023). Results indicate that ChatGPT shows preference for some regions over others, even when swapping the location strings of two profiles (counterfactuals). Furthermore, ChatGPT was more likely to assign certain developer roles to users from a specific country, revealing an implicit bias. Overall, this study reveals insights into the inner workings of LLMs and has implications for mitigating such societal biases in these models.

The recent observations by the James Webb Space Telescope (JWST) have revealed a larger number of bright galaxies at $z\gtrsim10$ than was expected. The origin of this excess is still under debate, although several possibilities have been presented. We propose that gamma-ray bursts (GRBs) are a powerful probe to explore the origin of the excess and, hence, the star and galaxy formation histories in the early universe. Focusing on the recently launched mission, Einstein Probe (EP), we find that EP can detect several GRBs annually at $z\gtrsim10$, assuming the GRB formation rate calibrated by events at $z\lesssim6$ can be extrapolated. Interestingly, depending on the excess scenarios, the GRB event rate may also show an excess at $z\simeq10$, and its detection will help to discriminate between the scenarios that are otherwise difficult to distinguish. Additionally, we discuss that the puzzling, red-color, compact galaxies discovered by JWST, the so-called ``little red dots'', could host dark GRBs if they are dust-obscured star forming galaxies. We are eager for unbiased follow-up of GRBs and encourage future missions such as HiZ-GUNDAM to explore the early universe., Comment: 13 pages, 5 figures, 2 tables, accepted for publication in ApJL

Written texts reflect an author's perspective, making the thorough analysis of literature a key research method in fields such as the humanities and social sciences. However, conventional text mining techniques like sentiment analysis and topic modeling are limited in their ability to capture the hierarchical narrative structures that reveal deeper argumentative patterns. To address this gap, we propose a method that leverages large language models (LLMs) to extract and organize these structures into a hierarchical framework. We validate this approach by analyzing public opinions on generative AI collected by Japan's Agency for Cultural Affairs, comparing the narratives of supporters and critics. Our analysis provides clearer visualization of the factors influencing divergent opinions on generative AI, offering deeper insights into the structures of agreement and disagreement.

Dark matter with mass in the crossover range between wave dark matter and particle dark matter, around $(10^{-3},\, 10^3)\,$eV, remains relatively unexplored by terrestrial experiments. In this mass regime, dark matter scatters coherently with macroscopic objects. The effect of the coherent scattering greatly enhances the accelerations of the targets that the dark matter collisions cause by a factor of $\sim 10^{23}$. We propose a novel torsion balance experiment with test bodies of different geometric sizes to detect such dark matter-induced acceleration. This method provides the strongest constraints on the scattering cross-section between the dark matter and a nucleon in the mass range $(10^{-5}, 10^3)\,$eV., Comment: 8 pages, 3 figures

We study nonequilibrium steady states (NESSs) in the weakly-coupled XXZ model in contact with two heat baths at different temperatures. We show that the density matrix can be represented using only projection operators specified by the quantum numbers of the quantum group $U_q(sl_2)$ in a very good approximation. By using this property, we numerically calculate physical quantities such as temperature profile, energy current, and correlation functions, for the spin chain consisting of several hundred spins. We analytically derive the exact density matrix in the limit $q \rightarrow 0$., Comment: 27 pages, 12 figures, to appear in J. Phys. Soc. Jpn

Solving the permutation problem is essential for determined blind source separation (BSS). Existing methods, such as independent vector analysis (IVA) and independent low-rank matrix analysis (ILRMA), tackle the permutation problem by modeling the co-occurrence of the frequency components of source signals. One of the remaining challenges in these methods is the block permutation problem, which may lead to poor separation results. In this paper, we propose a simple and effective technique for solving the block permutation problem. The proposed technique splits the entire frequencies into overlapping subbands and sequentially applies a BSS method (e.g., IVA, ILRMA, or any other method) to each subband. Since the problem size is reduced by the splitting, the BSS method can effectively work in each subband. Then, the permutations between the subbands are aligned by using the separation result in one subband as the initial values for the other subbands. Experimental results showed that the proposed technique remarkably improved the separation performance without increasing the total computational cost.

Hypergraphs provide a robust framework for modeling complex systems with higher-order interactions. However, analyzing them in dynamic settings presents significant computational challenges. To address this, we introduce a novel method that adapts the cardinality-based gadget to convert hypergraphs into strongly connected weighted directed graphs, complemented by a symmetrized combinatorial Laplacian. We demonstrate that the harmonic mean of the conductance and edge expansion of the original hypergraph can be upper-bounded by the conductance of the transformed directed graph, effectively preserving crucial cut information. Additionally, we analyze how the resulting Laplacian relates to that derived from the star expansion. Our approach was validated through change point detection experiments on both synthetic and real datasets, showing superior performance over clique and star expansions in maintaining spectral information in dynamic settings. Finally, we applied our method to analyze a dynamic legal hypergraph constructed from extensive United States court opinion data.

Simulating thermal-equilibrium properties at finite temperature is crucial for studying quantum many-body systems. Quantum computers are expected to enable us to simulate large systems at finite temperatures, overcoming challenges faced by classical computers, like the sign problem of the quantum Monte-Carlo technique. Conventional methods suitable for fault-tolerant quantum computing (FTQC) devices are designed for studying large-scale quantum many-body systems but require a large number of ancilla qubits and a deep quantum circuit with many basic gates, making them unsuitable for the early stage of the FTQC era, at which the availability of qubits and quantum gates is limited. In this paper, we propose a method suitable for quantum devices in this early stage to calculate the thermal-equilibrium expectation value of an observable at finite temperatures. Our proposal, named the Markov-chain Monte Carlo with sampled pairs of unitaries (MCMC-SPU) algorithm, involves sampling simple quantum circuits and generating the corresponding statistical ensembles. This approach addresses the issues of resource demand and the decay in probability associated with postselection of measurement outcomes on ancilla qubits. We validate our proposal with numerical simulation on the one-dimensional transverse-field Ising model as an illustrative example., Comment: 22 pages, 11 figures

Developers must select a high-performance fault localization (FL) technique from available ones. A conventional approach is to try to select only one FL technique that is expected to attain high performance before debugging activity. In contrast, we propose a new approach that dynamically selects better FL techniques during debugging activity., Comment: 2 pages, 2 figures, 1 table

Ensemble learning methods have been used to enhance the reliability of defect prediction models. However, there is an inconclusive stability of a single method attaining the highest accuracy among various software projects. This work aims to improve the performance of ensemble-learning defect prediction among such projects by helping select the highest accuracy ensemble methods. We employ bandit algorithms (BA), an online optimization method, to select the highest-accuracy ensemble method. Each software module is tested sequentially, and bandit algorithms utilize the test outcomes of the modules to evaluate the performance of the ensemble learning methods. The test strategy followed might impact the testing effort and prediction accuracy when applying online optimization. Hence, we analyzed the test order's influence on BA's performance. In our experiment, we used six popular defect prediction datasets, four ensemble learning methods such as bagging, and three test strategies such as testing positive-prediction modules first (PF). Our results show that when BA is applied with PF, the prediction accuracy improved on average, and the number of found defects increased by 7% on a minimum of five out of six datasets (although with a slight increase in the testing effort by about 4% from ordinal ensemble learning). Hence, BA with PF strategy is the most effective to attain the highest prediction accuracy using ensemble methods on various projects., Comment: 6 pages, 6 figures, 6 tables

Motivated by the recent acoustically driven spin resonance studies applied to silicon vacancy centers in silicon carbide, we theoretically investigate the spin--strain interaction characterized by the defect spin-$3/2$ quadrupole components coupled to strain fields. Considering the $C_{3v}$ symmetry of the vacancy site beyond the spherical approximation, we clarify the effect of a deviation from the spherical symmetry on spin resonance transition rate, which can be changed by rotating a static magnetic field. The ratios of spin--strain coupling parameters can be evaluated from the anisotropic field-direction dependence of the transition rate using a standing or traveling surface acoustic wave. We also discuss the effect of the propagation direction of the acoustic wave tilted from the crystallographic mirror plane reflecting the $C_{3v}$ symmetry. The results presented here reveal the quadrupole properties inherent in spin-3/2 states and will promote the realization of the acoustically driven strain control of spin., Comment: 9 pages, 16 figures

Motivated by the recent studies of acoustically driven electron spin resonance applied to diamond nitrogen-vacancy (NV) centers, we investigate the interaction of an electronic spin-triplet state with periodically time-dependent oscillating strain fields. On the basis of a lowest-lying two-level system, we show the importance of two-phonon transition probabilities controlled by rotating an applied magnetic field using the Floquet theory. In particular, we demonstrate how to evaluate coupling-strength parameters in the spin--strain interaction for the $C_{3v}$ point group considering the NV spin states. The level splitting of spin states can be adjusted by changing the field directions relative to the NV axis to obtain lower phonon resonance frequencies suitable for practical applications. Focusing on a field-rotation angle for the vanishment of a longitudinal phonon-mediated transition, we show that the magnetoacoustic resonance presented here provides useful information as a new probe of unquantified spin--strain couplings possessed by NV defects., Comment: 12 pages, 11 figures

SN 2023ixf is one of the most well-observed core-collapse supernova in recent decades, yet there is inconsistency in the inferred zero-age-main-sequence (ZAMS) mass $M_{\rm ZAMS}$ of its progenitor. Direct observations of the pre-SN red supergiant (RSG) estimate $M_{\rm ZAMS}$ spanning widely from 11 to 18 $M_{\rm \odot}$. Additional constraints, including host environment and the pulsation of its progenitor RSG, suggest a massive progenitor with $M_{\rm ZAMS}$ > 17 $M_{\rm \odot}$. However, the analysis of the properties of supernova, from light curve modeling to late phase spectroscopy, favor a relatively low mass scenario ($M_{\rm ZAMS}$ < 15 $M_{\rm \odot}$). In this work, we conduct systematic analysis of SN 2023ixf, from the RSG progenitor, plateau phase light curve to late phase spectroscopy. Using MESA+STELLA to simulate the RSG progenitor and their explosions, we find that, despite the ZAMS mass of the RSG models being varied from 12.0 to 17.5 $M_{\rm \odot}$, they can produce light curves that well match with SN 2023ixf if the envelope mass and the explosion energy are allowed to vary. Using late phase spectroscopy as independent measurement, the oxygen emission line [O I] suggests the ZAMS is intermediate massive (~16.0 $M_{\rm \odot}$), and the relatively weak H$\alpha$ emission line indicates the hydrogen envelope has been partially removed before the explosion. By incorporating the velocity structure derived from the light curve modeling into an axisymmetric model, we successfully generated [O I] line profiles that are consistent with the [O I] line observed in late phase spectroscopy of SN 2023ixf. Bringing these analyses together, we conclude that SN 2023ixf is the aspherical explosion of an intermediate massive star ($M_{\rm ZAMS}$ = 15-16 $M_{\rm \odot}$) with the hydrogen envelope being partially stripped to 4-5 $M_{\rm \odot}$ prior to its explosion., Comment: 12 pages, 4 figures. Submitted

The exploration of superconductors in metastable phases by manipulating crystal structures through high-pressure techniques has attracted significant interest in materials science to achieve a high critical temperature ($T_c$). In this study, we report an emergence of novel superconductivity in a metastable phase of Th$_3$P$_4$-type cubic In$_{3-x}$S$_4$ with remarkably high $T_c$ at 20 K under 45 GPa by using an originally designed diamond anvil cell equipped with boron-doped diamond electrodes, which can perform a high-pressure synthesis and an in-situ electrical transport measurement simultaneously. In-situ structural analysis indicates that the In$_{3-x}$S$_4$ appears partially above 40 GPa without heating. The high-pressure annealing treatment induces complete transformation to the Th$_3$P$_4$-type structure, and the defected concentration of x in In$_{3-x}$S$_4$ decreases with increasing annealing temperature. The $T_c$ in In$_{3-x}$S$_4$ is maximized at x = 0 and approaches 20 K. Electronic band calculations show that the high density of states composed of sulfur and indium bands are located at the conduction band bottom near Fermi energy. The record high $T_c$ in In$_{3-x}$S$_4$ among superconducting sulfides accelerates the further exploration of high $T_c$ materials within the Th$_3$P$_4$-type cubic family by using flexibility in crystal structure.