bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gravitation as a Statistical Theory on the Light Cone
Authors: Isidro J M , Paganini Claudio Francesco , Pesci Alessandro 
Published: January 2025

Abstract
In this paper, we will explore Padmanabhan’s mesoscopic, statistical approach to gravity [62] with a twist. The general picture of his approach is that spacetime is made of large numbers of localized quantum degrees of freedom. Padmanabhan assumed that the degrees of freedom of a given quantum state of geometry contribute, after averaging over fluctuations, a vector degree of freedom for spacetime at a point. For null vectors, this can be regarded as corresponding to one single vector, i.e. a pure state, for the statistical ensemble on the light cone at every point. In the present paper, we consider instead the case where the states of the gravitational degrees of freedom are spread out and overlap, with only probabilistic information on which of them determines the actual spacetime at a point. In the continuum limit, this corresponds to a mixed state for the statistical ensemble on the light cone at every point.&#xD;&#xD;This change in assumptions leads to some interesting observations. When we define a statistical ensemble on the light cone, its variance ``knows'' about the interior of the light cone. As an intriguing consequence, we find that the cosmological constant can be related to the variance over the light cone.&#xD;&#xD;With a mixed state, we can no longer derive the gravitational field equations from an entropy functional. Here, instead, we show that a naive implementation of the measure of a mixed state on the light cone in the variation principle leads to modified measure theories (MMT) as the grand canonical ensemble and allows one to reframe unimodular gravity as the canonical ensemble of a statistical theory on the light cone.
High Q-factor Mie lattice resonance generated from out-of-plane magnetic dipole in all-dielectric defected semi-cylinder metasurface array
Authors: Zhang Lei , Liang Kunlin , Sun Chengchen , Tu Shijuan , Fu Qin , Feng Shuai , Du Qingguo , Li Zhengying , Xu Fei 
Published: January 2025

Abstract
Due to the weak far-ﬁeld radiation and strong local ﬁeld enhancement properties of Mie lattice resonances, transmission resonance with signiﬁcant high Q factor is achieved which could be used in applications such as refractive index sensing, ﬁltering and nano lasing. In this paper, we design an semi-cylinder with cuboid defect metasurface array working in the near-infrared, where a resonance with extremely narrow linewidth in transmission spectrum has been demonstrated at the wavelength of 870.9408 nm. The full width at half-maximum of the resonance is as narrow as 0.0032 nm with a corresponding Q factor of 272169. According to distributions of the electric ﬁeld and displacement current, it is conﬁrmed that the narrow linewidth resonance is generated from the Mie lattice resonance which is originated from the coupling between the out-of-plane magnetic dipole mode with Rayleigh Anomalous diﬀraction. It is further veriﬁed that the out-of-plane magnetic dipole mode is excited due to the induced defect in the semi-cylinder. When being applied in refractive sensing, a sensitivity and a ﬁgure of merit of 333 nm/RIU and 104063 RIU-1 are numerically achieved simultaneously. Our study here provide a new way for achieving resonances with high Q-factors.&#xD;
Role of spin-orbit coupling for the band splitting in ⍺-Sb and ⍺-Bi on SiC(0001)
Authors: Yaegashi Ken , Sugawara Katsuaki , Takahashi Takashi , Sato Takafumi 
Published: January 2025

Abstract
Monolayer atomic thin ﬁlms of group-V elements have a high potential for application in spintronics and valleytronics because of their unique crystal structure and strong spin-orbit coupling. We fabricated Sb and Bi monolayers on a SiC(0001) substrate by the molecular-beam-epitaxy method and studied the electronic structure by angle-resolved photoemission spectroscopy (ARPES) and ﬁrst-principles calculations. The fabricated Sb ﬁlm shows the (√3×√3)R30º superstructure associated with the formation of ⍺-Sb, and exhibits a semiconducting nature with a band gap of more than 1.8 eV. Spin-resolved ARPES measurements of isostructural ⍺-Bi revealed the in-plane spin polarization for the topmost valence band, demonstrating its Rashbasplittingof nature due to the space-inversion-symmetry breaking. We discuss the originobserved characteristic band structure and its similarity and difference between Sband Bi.&#xD;
Coupling of single nanodiamonds hosting SiV color centers to plasmonic double bowtie microantennas
Authors: Lindner Sarah , Rahbany Nancy , Pauly Christoph , Gines Laia , Mandal Soumen , Williams Oliver A , Muzha Andreas , Krueger Anke , Bachelot Renaud , Couteau Christophe , Becher Christoph 
Published: January 2025

Abstract
Color centers are promising single-photon emitters owing to their operation at room temperature and high photostability. In particular, using nanodiamonds as a host material is of interest for sensing and metrology. Furthermore, being a solid-state system allows for incorporation to photonic systems to tune both the emission intensity and photoluminescence spectrum and therefore adapt the individual color center to desired properties. We show successful coupling of a single nanodiamond hosting silicon-vacancy color centers to a plasmonic double bowtie antenna structure. To predict the spectrum of the coupled system, the photoluminescence spectrum of the SiV centers was measured before the coupling process and convoluted with the antenna resonance spectrum. After transferring the nanodiamond to the antenna the combined spectrum was measured again. The measurement agrees well with the calculated prediction of the coupled system and therefore confirms successful coupling.
Study of the effect of circular p-GaN gate on the DC characteristics of AlGaN/GaN HEMTs
Authors: Zhu Yanxu , Wang Yuhan , Luo Dan , Yang Xiaolong , Li Qian , Fei Baoliang , Gong Yanfei 
Published: January 2025

Abstract
In this paper, we use Silvaco-ATLAS two-dimensional numerical simulation to calculate the performance of two different circular-gate AlGaN/GaN HEMT device models. The influence of the special circular-gate structure on the DC characteristics of the AlGaN/GaN HEMT device is studied and compared with that of conventional devices. Compared with conventional, the threshold voltage of the drain-center and source-center circular-gate devices increased from 1.1 V to 1.5 V, while the transconductance improved from 245 mS/mm to 328 mS/mm and 285 mS/mm respectively. In the on-state of devices, the maximum saturation output current increased from 536 mA/mm to 620 mA/mm and 650 mA/mm. Furthermore, the breakdown voltage of the source-center circular-gate device rose from 765 V to 870 V compared to conventional devices; however, for the drain-center circular-gate device it was only at 685 V due to concentrated electric fields outside the drain region—this limitation can be effectively addressed by increasing the drain area. Simulation results demonstrate that circular-gate AlGaN/GaN HEMT devices can avoid edge effects, improve electric field distribution, and alleviate self-heating effects.&#xD;
Metal-Semiconductor-Metal Photodiode Fabricated With an AlGaN/AlN Superlattice for UV Light Detection
Authors: Wang Tong-Wen , Sharma Mukta , Tsai Chia-Lung , Zhang Jin-Rong 
Published: January 2025

Abstract
We designed and fabricated a nonplanar metal-semiconductor-metal (MSM) ultraviolet (UV) photodetector (PD), incorporating a 30-pair Al0.5Ga0.5N/AlN superlattice (SL) absorption layer on a GaN on a sapphire substrate. In contrast to conventional PDs featuring a 100-nm-thick Al0.25Ga0.75N epilayer, our proposed PDs with the higher Al content of Al0.5Ga0.5N/AlN SLs did not exhibit degradation in epiwafer quality. Furthermore, we observed that the use of Al0.5Ga0.5N/AlN SLs resulted in a higher optical gain, specifically achieving voltage-dependent photoresponsivity in the MSM PDs. This improvement was observed with both the ohmic-type Ti/Al/Ni/Au (top) and the Schottky-type Ni/Au (bottom) electrodes, as well as with two Ni/Au Schottky metal electrodes. With the incorporation of Al0.5Ga0.5N/AlN SLs, our proposed MSM PDs with an Ohmic/Schottky-type electrode configuration showcased an enhanced photoresponsivity of 1129.8 A/W at ‒5 V in comparison to MSM PDs employing two Schottky-type electrodes. Moreover, by utilizing the Al0.5Ga0.5N/AlN SL absorption layer, we achieved an increased light current to dark current ratio, reaching 3.66 × 105 biasing at a ‒7 V. Following the implementation of our proposed MSM PDs with an Ohmic/Schottky-type electrode configuration, the gain ratio improvement underscores the efficacy of this approach. Subsequently, the fabricated device's transient response, demonstrating enhanced output performance, was analyzed using an in-house optical transmission setup. The estimated 3-dB cut-off frequency of this proposed MSM PD was found to be approximately 1.2 MHz.&#xD;
Personalized μ-transcranial alternating current stimulation improves online brain-computer interface control
Authors: Liu Deland Hu , Kumar Satyam , Alawieh Hussein , Racz Frigyes Samuel , Millan Jose del R 
Published: January 2025

Abstract
Objective. A motor imagery (MI)-based brain-computer interface (BCI) enables users to engage with external environments by capturing and decoding electroencephalography (EEG) signals associated with the imagined movement of specific limbs. Despite significant advancements in BCI technologies over the past 40 years, a notable challenge remains: many users lack BCI proficiency, unable to produce sufficiently distinct and reliable MI brain patterns, hence leading to low classification rates in their BCIs. The objective of this study is to enhance the online performance of MI-BCIs in a personalized, biomarker-driven approach using transcranial alternating current stimulation (tACS). Approach. Previous studies have identified that the peak power spectral density (PSD) value in sensorimotor idling rhythms is a neural correlate of participants’ upper limb MI-BCI performances. In this active-controlled, single-blind study, we applied 20 minutes of tACS at the participant-specific, peak µ frequency in resting-state sensorimotor rhythms (SMRs), with the goal of enhancing resting-state µ SMRs. Main Results. After tACS, we observed significant improvements in event-related desynchronizations (ERDs) of µ sensorimotor rhythms (SMRs), and in the performance of an online MI-BCI that decodes left versus right hand commands in healthy participants (N=10) —but not in an active control-stimulation control group (N=10). Lastly, we showed a significant correlation between the resting-state µ SMRs and µ ERD, offering a mechanistic interpretation behind the observed changes in online BCI performances. Significance. Our research lays the groundwork for future non-invasive interventions designed to enhance BCI performances, thereby improving the independence and interactions of individuals who rely on these systems.
Adaptive anomaly detection disruption prediction starting from first discharge on tokamak
Authors: Ai Xinkun , Zheng Wei , Zhang Ming , Ding Yong Hua , Chen Dalong , Chen Zhongyong , Guo Bihao , Shen Chengshuo , Wang Nengchao , Yang Zhoujun , Chen Zhipeng , Pan Yuan , Shen Biao , Xiao Bingjia 
Published: January 2025

Abstract
Plasma disruption presents a significant challenge in tokamak fusion, especially in large-size devices like ITER, where it causes severe damage. While current data-driven machine learning methods perform well in disruption prediction, they require extensive discharge data for model training. However, future tokamaks will begin operations without any prior data, making it difficult to train data-driven disruption predictors and select appropriate hyperparameters during the early operation period. In this period disruption prediction also aims to support safe exploration of operation range and accumulate necessary data to develop advanced prediction models. Thus, predictors must adapt to evolving plasma states during this exploration phase. To address these challenges, this study further develops the Enhanced Convolutional Autoencoder Anomaly Detection (E-CAAD) predictor and proposes a cross-tokamak adaptive transfer method based on E-CAAD. By training the E-CAAD model on data from existing devices, the predictor can effectively distinguish between disruption precursor and non-disruption samples in new device, enabling disruption prediction from the first shot on the new device. Additionally, adaptive learning from scratch and alarm threshold adaptive adjustment strategies are proposed to enable model automatically adapt to changes in the discharge scenario. The adaptive learning strategy enables the predictor to fully use scarce data during the early operation of the new device while rapidly adapting to changes in the discharge scenario. The threshold adaptive adjustment strategy addresses the challenge of selecting alarm thresholds on new devices where the validation set is lacking, ensuring that the alarm thresholds adapt to changes in the discharge scenario. Finally, the experiment transferring the model from J-TEXT to EAST exhibit that this method enables disruption prediction from the first shot on EAST, allowing the predictor to adapt to changes in the discharge scenario and maintain high prediction performance.
Land conversions not climate effects are the dominant indirect consequenceof sun-driven CO2 capture, conversion, and sequestration
Authors: Adam Moritz , Kleinen Thomas , May Matthias , Rehfeld Kira 
Published: January 2025

Abstract
Removing carbon dioxide (CO2) from the atmosphere is required for mitigating climate change. Large-scale direct air capture combined with injecting CO2 into geological formations could retain carbon long-term, but demands a substantial amount of energy, pipeline infrastructure, and suitable sites for gaseous storage. Here, we study Earth system impacts of modular, sun-powered process chains, which combine direct air capture with (electro)chemical conversion of the captured CO2 into liquid or solid sink products and subsequent product storage (sDACCCS). Drawing on a novel explicit representation of CO2 removal in a state-of-the-art Earth system model, we find that these process chains can be renewably powered and have minimal implications for the climate and carbon cycle. However, to stabilize the planetary temperature two degrees above pre-industrial levels, CO2 capturing, conversion, and associated energy harvest demand up to 0.46% of the global land area in a high-efficiency scenario. This global land footprint increases to 2.82% when assuming present-day technology and pushing to the bounds of removal. Mitigating historical emission burdens within individual countries in this high-removal scenario requires converting an area equivalent to 40% of the European Union's agricultural land. Scenarios assuming successful technological development could halve this environmental burden, but it is uncertain to what degree they could materialize. Therefore, ambitious decarbonization is vital to reduce the risk of land use conflicts if efficiencies remain lower than expected.
BKT transitions of the XY and six-state clock models on the various two-dimensional lattices
Authors: Okabe Yutaka , Otsuka Hiromi 
Published: January 2025

Abstract
In a two-dimensional (2D) spin system, the XY model, characterized by planar rotational symmetry, exhibits a unique phenomenon known as the Berezinskii-Kosterlitz-Thouless (BKT) transition. In contrast, the clock model, which introduces discrete rotational symmetry, exhibits the BKT transition at two different temperatures due to this discreteness.&#xD;In this study, we numerically investigate the BKT transition for XY and six-state clock models over various two-dimensional lattices. We employ two primary methods: the Monte Carlo method, which analyzes the size dependence of the ratio of the correlation functions for two different distances, and a machine-learning approach to classify the different phases --- namely, the low-temperature ordered phase, the intermediate BKT phase, and the high-temperature disordered phase.&#xD;We identify the BKT transition temperatures for the XY and six-state models on honeycomb, kagome, and diced lattices. &#xD;Combined with the previously calculated data for the triangular lattice, we then compare these values with the second-order phase transition temperatures of the 2D Ising model, for which exact solutions are known. &#xD;Our results indicate that the ratio of the BKT transition temperatures for each lattice relative to the Ising model transition temperatures are close, although the values are not universal. &#xD;
Microwave synthesis of molybdenum disulfide quantum dots and the application in bilirubin sensing
Authors: Pang Shu , Chang Xinyu , Xu Lin , Wu Jiazhen 
Published: January 2025

Abstract
Molybdenum disulfide quantum dots (MoS2 QDs) is a new type of graphite like nanomaterial, which exhibited well chemical stability, unique fluorescence characteristics, and excellent biocompatibility. The conventional hydrothermal synthesis of MoS2 generally requires a long-term reaction at high temperature and high pressure. Herein, we have developed a simple and fast MoS2 QDs synthesis scheme using microwave heating, and further modified the surface of MoS2 QDs using 3-aminophenylboronic acid. The 3- aminophenylboronic acid modified MoS2 QDs (B-MoS2 QDs) were further coated by a zinc-based metal-organic backbone (ZIF-8) in a solution containing zinc ions and 2-methylimidazolium. The constructed nanohybrid B-MoS2@ZIF-8 were successfully applied to the visualization and rapid detection of bilirubin based on the ratiometric fluorescence changes. The linear range for bilirubin detection is 0.2-75 μmol•L-1, and detection limit is 0.017 μmol•L-1.
Recent progress in two-dimensional polymer materials: interfacial synthesis and applications
Authors: Ma Lili , Hou Wenbo , Li Anbai , Peng Hui , Xie Xuan , Ma Guofu , Xu Yuxi 
Published: January 2025

Abstract
As a new two-dimensional polymer synthetic material, two-dimensional polymers (2DPs) not only have the advantages of high specific surface area and high transparency of two-dimensional materials, but also have the advantages of high mechanical strength and easy processing of polymer materials. Therefore, 2DPs are widely used and have become one of the indispensable materials today. However, there are still challenges in preparing 2DPs using traditional methods. Among the various synthesis strategies, the interfacial synthesis methods with the advantages of simple operation and high crystallinity have become typical method for preparing 2DPs. In this review, we first summarize the types of interface synthesis methods and the latest research progress. Secondly, the 2DPs applications in optoelectronic devices, membrane separation, sensor, electrical device and batteries, etc. are introduced. Finally, we summarize and prospect the existing challenges and future research directions based on the current research status of 2DPs.&#xD;
Continuous-variable quantum key distribution with noisy squeezed states
Authors: Oruganti Akash Nag , Derkach Ivan , Filip Radim , Usenko Vladyslav C 
Published: January 2025

Abstract
We address the crucial role of noisy squeezing in security and performance of&#xD;continuous-variable (CV) quantum key distribution (QKD) protocols. Squeezing has&#xD;long been recognized for its numerous advantages in CV QKD, such as enhanced&#xD;robustness against channel noise and loss, and improved secret key rates. However, the&#xD;excess noise of the squeezed states, that unavoidably originates already from optical&#xD;loss as well as other imperfections in the source, raises concerns about its potential&#xD;exploitation by an eavesdropper. For the widely adopted trust assumption on the excess&#xD;noise in the signal states, we confirm the stability of the protocol against the noisy&#xD;squeezing in both purely attenuating as well as noisy channels in the asymptotic limit,&#xD;which implies perfect parameter estimation. In the finite-size regime we show that&#xD;this stability largely holds at up to 107 data points using optimal biased homodyne&#xD;detection for key distribution and parameter estimation. Untrusted assumption on&#xD;the noisy squeezing, on the other hand, introduces additional security bounds on the&#xD;squeezing excess noise already in the asymptotic regime, which is further enforced&#xD;by the finite-size effects. Additionally, we show the critical negative role of noisy&#xD;squeezing in the case of atmospheric free-space channels, already in the trusted-noise&#xD;and asymptotic assumptions, which emphasizes the importance of squeezing purity&#xD;in the free-space quantum channels. Our results pave the way towards practical&#xD;realization of squeezed-state CV QKD protocols in both fibre and free-space channels.
Quantum integration of decay rates at second order in perturbation theory
Authors: Martinez De Lejarza Jorge J. , Renteria-Estrada David F. , Grossi Michele , Rodrigo German 
Published: January 2025

Abstract
We present the first quantum computation of a total decay rate in high-energy physics at second order in&#xD;perturbative quantum field theory. This work underscores the confluence of two recent cutting-edge advances.&#xD;On the one hand, the quantum integration algorithm Quantum Fourier Iterative Amplitude Estimation (QFIAE),&#xD;which efficiently decomposes the target function into its Fourier series through a quantum neural network before quantumly integrating the corresponding Fourier components. On the other hand, causal unitary in the&#xD;loop-tree duality (LTD), which exploits the causal properties of vacuum amplitudes in LTD to coherently generate all contributions with different numbers of final-state particles to a scattering or decay process, leading to&#xD;singularity-free integrands that are well suited for Fourier decomposition. We test the performance of the quantum algorithm with benchmark decay rates in a quantum simulator and in quantum hardware, and find accurate&#xD;theoretical predictions in both settings.
Conceptual framework to integrate food waste research and food systems research
Authors: Rolker Heike B B , Cardenas Laura M. , Reynolds Christian , Takahashi Taro 
Published: January 2025

Abstract
It is estimated that a quarter to one-third of food intended for humans does not fulfil its original purpose. Yet, and despite its universally acknowledged importance for sustainability, mechanisms behind food waste generation are often studied unconnectedly from other challenges surrounding food systems. Here, we examine how concepts, assumptions and frameworks adopted in the food waste literature and the food systems literature overlap, contradict and complement one another. We discuss the current evidence on why and how food waste occurs and discuss modifications required for a conceptual framework to improve the integration between the two groups of studies. The resulting framework makes an explicit distinction between context-specific direct causes and context-independent indirect drivers of food waste, with practice theory interlinking them by portraying human behaviour and associated agency that translate the latter into the former. Central to our conceptualisation is an enhanced recognition that the ultimate cause of food waste is almost always natural decay, which cannot be prevented but can be managed through a systems approach with clear definitions of temporal boundaries.