[article-cris] Perustieteiden korkeakoulu / SCI

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  • What is emergence, after all?
    (2026-02-01) Rizi, Abbas K.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The term emergence is increasingly used across scientific disciplines to describe phenomena that arise from interactions among a system's components but cannot be readily inferred by examining those components in isolation. While often invoked to explain higher-level behaviors—such as flocking, synchronization, or collective intelligence—the term is frequently used without precision, sometimes giving rise to ambiguity or even mystique. In this perspective paper, I clarify the scientific meaning of emergence as a measurable and physically grounded phenomenon. Through concrete examples—such as temperature, magnetism, and herd immunity in social networks—I review how collective behavior can arise from local interactions that are constrained by global boundaries. By refining the concept of emergence, it is possible to gain a clearer and more grounded understanding of complex systems. My goal is to show that emergence, when properly framed, offers not mysticism, but rather insight.
  • Universal route to chiral Ising superconductivity in monolayer TaS2 and NbSe2
    (2025-12-29) Gibelli, Lucia; Höcherl, Simon; Siegl, Julian; Vaňo, Viliam; Ganguli, Somesh C.; Marganska, Magdalena; Grifoni, Milena
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We investigate Ising superconductivity in two archetypal intrinsic superconductors, monolayer 1H − TaS2 and 1H − NbSe2, in a bottom-up approach. Using ab initio-based tight-binding parametrizations for the relevant low-energy d bands, the screened interaction is evaluated microscopically in a scheme including Bloch overlaps. In direct space, the screened potential for both systems displays long-range Friedel oscillations alternating in sign. Upon scaling, the oscillation pattern becomes universal, with the location of minima and maxima locked to the lattice. Solving the momentum-resolved gap equations, a chiral ground state with p-like symmetry is generically found. Due to the larger Ising spin-orbit coupling, the chiral gap is more anisotropic in TaS2 than in NbSe2. This is reflected in tunneling spectra displaying V-shaped features for the former, in quantitative agreement with low-temperature scanning tunneling experiments on TaS2. At the same time, our results reconcile the apparent discordance with hard gap tunneling spectra reported for the sibling NbSe2.
  • Improvements in EHR usability during eleven years : Cross-sectional surveys on specialist physicians’ experiences in Finland
    (2026-06-01) Viitanen, Johanna; Nisula, Sara; Tuovinen, Timo; Lääveri, Tinja
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Background: Usability not only impacts user satisfaction but also the efficiency and effectiveness of electronic health record (EHR) use. Moreover, poor EHR usability is associated with physician burnout and stress. Despite an abundance of research and investments in improving usability, long-term monitoring studies are scarce. Our aim was to explore how the usability of EHR systems has evolved over an 11-year period in Finland from specialist physicians’ perspectives and to compare user experiences (UXs) between specialties. Methods: Nationwide usability-focused cross-sectional surveys were conducted among Finnish physicians in 2010, 2014, 2017, and 2021. To measure usability, we selected six usability-related statements from the validated National Usability-focused Health Information System Scale (NuHISS). The responses of specialist physicians with more than six months of system use (n = 2473 in 2021; 2137 in 2017; 2162 in 2014; and 2312 in 2010) were selected and analyzed by specialty group and study year. Results: During the study years, UXs improved across all specialty groups. A positive change was seen particularly in occupational healthcare (OH) and nonsurgical medical specialties. However, the Net EHR Experience Scores (NEESs) remained negative for all groups, except for physicians working in anesthesiology and intensive care. In 2021, physicians working in OH and general practice were more positive about EHR usability, whereas those in psychiatric specialties gave more negative assessments than other groups. Conclusion: Despite improvements over the study years, most physicians remained dissatisfied with EHRs. Interestingly, the positive development was not linear; during 2014–17, NEESs decreased, coinciding with the implementation of the national health information exchange services. Our findings suggest that efforts to improve EHR usability and enhance end-user skills only slowly translate into better UXs. To distinguish the effect of factors such as national requirements or recently implemented EHR brands, continuous monitoring of UXs using context-adapted surveys like NuHISS is crucial.
  • Roadmap on quantum thermodynamics
    (2026-03-01) Campbell, Steve; D'amico, Irene; Ciampini, Mario A.; Anders, Janet; Ares, Natalia; Artini, Simone; Auffeves, Alexia; Oftelie, Lindsay Bassman; Bettmann, Laetitia P.; Bonanca, Marcus V. S.; Busch, Thomas; Campisi, Michele; Cavalcante, Moallison F.; Correa, Luis A.; Cuestas, Eloisa; Dag, Ceren B.; Dago, Salambo; Deffner, Sebastian; Del Campo, Adolfo; Deutschmann-Olek, Andreas; Donadi, Sandro; Doucet, Emery; Elouard, Cyril; Ensslin, Klaus; Erker, Paul; Fabbri, Nicole; Fedele, Federico; Fiusa, Guilherme; Fogarty, Thomas; Folk, Joshua; Guarnieri, Giacomo; Hegde, Abhaya S.; Hernandez-Gomez, Santiago; Hu, Chang-Kang; Iemini, Fernando; Karimi, Bayan; Kiesel, Nikolai; Landi, Gabriel T.; Lemziakov, Sergei; Lo Monaco, Gabriele; Lutz, Eric; Lvov, Dmitrii; Maillet, Olivier; Mehboudi, Mohammad; Mendonca, Taysa M.; Miller, Harry J. D.; Mitchell, Andrew K.; Mitchison, Mark T.; Mukherjee, Victor; Paternostro, Mauro; Pekola, Jukka; Perarnau-Llobet, Marti; Poschinger, Ulrich; Rolandi, Alberto; Rosa, Dario; Sanchez, Rafael; Santos, Alan C.; Sarthour, Roberto S.; Sela, Eran; Solfanelli, Andrea; Souza, Alexandre M.; Splettstoesser, Janine; Tan, Dian; Tesser, Ludovico; Van Vu, Tan; Halpern, Nicole Yunger; Zawadzki, Krissia
    A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    The last two decades have seen quantum thermodynamics become a well established field of research in its own right. In that time, it has demonstrated a remarkably broad applicability, ranging from providing foundational advances in the understanding of how thermodynamic principles apply at the nano-scale and in the presence of quantum coherence, to providing a guiding framework for the development of efficient quantum devices. Exquisite levels of control have allowed state-of-the-art experimental platforms to explore energetics and thermodynamics at the smallest scales which has in turn helped to drive theoretical advances. This Roadmap provides an overview of the recent developments across many of the field's sub-disciplines, assessing the key challenges and future prospects, providing a guide for its near term progress.
  • Growth and prediction of plastic strain in metallic glasses
    (2026-02) Mäkinen, Tero; Parmar, Anshul D.S.; Bonfanti, Silvia; Alava, Mikko J.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Predicting the failure and plasticity of solids remains a longstanding challenge, with broad implications for materials design and functional reliability. Disordered solids like metallic glasses can fail either abruptly or gradually without clear precursors, and the mechanical response depends strongly on composition, thermal history, and deformation protocol—impeding generalizable modeling. While deep learning methods offer predictive power, they often rely on numerous input parameters, hindering interpretability, methodology advancement, and practical deployment. We address this longstanding challenge with a macroscopic, physically grounded approach that uses plastic strain accumulation in the elastic regime to robustly predict deformation and yield. This method reduces complexity and improves interpretability, offering a practical alternative for disordered materials. For the Cu-Zr-(Al) metallic glasses prepared with varied annealing, we identify two limiting regimes of plastic strain growth: power law in poorly annealed and exponential in well-annealed samples. A physics-informed framework with Bayesian inference extracts growth parameters from stress-strain data within ∼5% strain, enabling early prediction of bulk response and yield point, well before the failure. The predictive performance improves with annealing and bulk plasticity correlates with the microscopic plastic activity from scattered to growth near yielding. This work presents a physically interpretable and experimentally relevant framework for predicting plasticity, stress-strain curve, and failure in metallic glasses from early mechanical response, offering both theoretical insights and practical tools for material characterization and design.
  • Modelling of the effect of particle species on beam losses in W7-X
    (2026-02-01) Sanchis, L.; Kurki-Suonio, T.; Särkimäki, K.; Ollus, P.; Kontula, J.; Äkäslompolo, S.; Lazerson, S.; Bozhenkov, S.; Smith, H. M.; , W7-X Team
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In Wendelstein 7-X (W7-X), future campaigns will include H, D and He as both NBI injection and target plasmas but, so far, only H injection and target plasmas have been extensively performed. The species effect on the beam-ion confinement and associated power loads has been studied with the ASCOT code to estimate the location and intensity of the hot spots. For this analysis, standard, high and low mirror configurations were considered to provide results covering the variation of the mirror term most likely to affect the beam-ion behaviour. Beam-ion losses were highest for D beams and lowest for He beams. Changing the target plasma from hydrogenic species to helium also produced higher losses. Hot-spot analysis showed peak loads up to 3 MW m-2 for D beams, with 1 MW m-2 and 0.1 MW m-2 for H and He beams, respectively. Losses were predominantly to carbon components independent of the mirror term. This is particularly apparent for the low-mirror configuration, showing that 97%-99% of the power loads avoid the more delicate steel components. The results of the helium injection and target plasmas can be validated against experimental results in the upcoming campaign to support the results for the deuterium modelling.
  • Enhancing Audio-Visual Learning : Cross-Modal Adaptation of Vision Transformers
    (2026) Radman, Abduljalil; Laaksonen, Jorma
    A4 Artikkeli konferenssijulkaisussa
    Pre-trained Vision Transformers (ViTs) face challenges in effectively extracting features for multimodal tasks due to their initial training on single-modality data. Moreover, fine-tuning ViTs for such tasks requires adjusting a significant number of parameters, leading to substantial training and storage costs. In audio-visual multimodal learning, a major challenge is seamlessly integrating both audio and visual cues into the transfer learning process, which can be particularly challenging with pre-trained ViTs. In this paper, we introduce a cross-modal audio-visual parameter-efficient adapter (AV-PEA). By integrating AV-PEA into a frozen ViT, the transformer becomes adept at processing audio inputs without prior audio pre-training, incorporating a minimal set of trainable parameters into each block. AV-PEA also facilitates the exchange of essential audio-visual cues between modalities while keeping the majority of the transformer’s parameters frozen, thus preserving its established knowledge base. Experimental results demonstrate that AV-PEA consistently achieves superior or comparable performance to state-of-the-art methods in various audio-visual downstream tasks, including audio-visual event localization, audio-visual question answering, audio-visual segmentation, audio-visual retrieval, and audio-visual captioning. Additionally, AV-PEA allows seamless integration into these tasks while maintaining a minimal number of trainable parameters, typically accounting for less than 3.7% of the total parameters per task.
  • AI innovation at the boundaries : Justifying a generative AI decision support tool
    (2026-03-01) Choroszewicz, Marta; Rannisto, Antti
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The growing uptake of generative AI by public administrations raises important questions about the continuity of AI innovations and the ‘thingness’ of AI, despite recurrent failures of these emerging technologies to fulfil their promises. We combine the frameworks of boundary work and regimes of justification and methodologically draw on nearly 1.5 years of ethnographic fieldwork following the innovation process of a generative AI decision support tool in a Finnish public organization. We capture how the team driving this AI innovation engages in boundary-crossing practices, enacting diverse conceptions of moral and common good to ensure the continuity of the tool's development process. We identified nine powerful justification frames related to the tool, its innovation process and its underlying ideology that sustained the generative AI tool's innovation. Three frames in particular – centring on efficiency, well-being and equality – formed a powerful trio capable of making the tool compelling across organizational boundaries within the context of the Nordic welfare state. The frames fostered a protective structure around the tool, simultaneously legitimizing it as it was developed. We show how enacting these frames to safeguard the tool and its imagined value from criticism – specifically a lack of accuracy, precision and consistency – made it an irresistible thing to influential organizational actors.
  • Ideal quantum geometry of the surface states of rhombohedral graphite and its effects on the surface superconductivity
    (2026-01-14) Jiang, Guodong; Heikkilä, Tero T.; Törmä, Päivi
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The interplay of quantum geometry and interactions determines the correlated state properties of flat bands. Here, we investigate the ideal quantum geometry (IQG), i.e., the property that the trace of quantum metric equals the Berry curvature, in the surface flat bands of rhombohedrally stacked graphene (RG) multilayers. We show that RG represents a class of semimetals with IQG, among which only RG has a nonvanishing IQG at the center of the surface bands. In the presence of long-range hoppings, a displacement field polarizes the electron density to one of the two surfaces, stabilizing the IQG and boosting transitions to correlated phases like superconductivity. Analyzing the superfluid stiffness of the superconducting state in a many-layer RG, we reveal a heavy-fermion picture where the “heavy electrons” carry a nonzero supercurrent. This unusual behavior arises from the IQG of the surface states, which suggests a large fraction of supercurrent running on the surface of RG.
  • Machine-learned interatomic potential for Fe–Co–X (X = Re, W) alloys : Ductility–brittleness behavior at finite temperatures
    (2026-03) Cheng, Haixia; Wang, Yanzhou; Song, Keke; Song, Minhui; Hou, Yaqing; Bi, Zhongnan
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Fe–Co alloys combine high strength with poor ductility, limiting their structural applications at elevated temperatures. To overcome this limitation, we developed a machine-learned interatomic potential within the Neuroevolution Potential (NEP) framework for the Fe–Co–Re–W system, trained via active learning on ab initio and molecular dynamics datasets. The model reproduces DFT-level energies, forces, and elastic properties with high fidelity, enabling large-scale finite-temperature simulations. Across 300–1500 K, the elastic response follows a hierarchy of B2>A2>A1 for stiffness and the inverse for ductility, with all phases satisfying the Born–Huang stability criteria. At 300 K, Re and W doping enhance ductility by increasing ν and B/G, while FeCoW shows a pronounced increase in the elastic ductility indicators and approaches the empirical ductile–brittle thresholds around 1000 K. W induces stronger ductility in B2 and A1, whereas Re improves toughness in A2. This work provides an accurate and efficient framework for exploring and designing ductile Fe–Co–X (X = Re, W) high-temperature structural alloys within the tested conditions.
  • Functional mapping of the somatotopic organization of the supplementary motor area using navigated repetitive transcranial magnetic stimulation and computer vision-based analysis
    (2026) Stein, Jonathan; Picht, Thomas; Engelhardt, Melina
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Background: The supplementary motor area (SMA) is a cortical region involved in motor and language functions. Motor representations within the SMA follow a somatotopic organization: Anterior regions are linked to orofacial movements, middle regions to upper limb movements, and posterior regions to lower limb movements. SMA lesions may produce impairments that correspond to this somatotopy; therefore, preoperative assessment may aid diagnosis. Objective: This study aimed to revise and extend a protocol for assessing the SMA using navigated repetitive transcranial magnetic stimulation (nrTMS), incorporating somatotopic organization and validating positive stimulation points against non-motor regions. Methods: The dominant-hemisphere SMA of 30 healthy participants (27.1 ± 6.21 years, 18 female) was examined. After mapping of the primary motor cortex with single-pulse TMS, six predefined SMA sites were stimulated using 20 Hz nrTMS while participants performed the Nine Hole Peg Test (NHPT; 120% resting motor threshold (RMT)), the lower extremity motor coordination test (LEMOCOT; 140% RMT), and an orofacial task (130% RMT). Each test was repeated under identical parameters at non-motor control sites. Kinematic measurements were obtained using high-speed recordings. Results: SMA stimulation disrupted upper extremity function, with the strongest effects observed at posterior sites. In contrast, lower extremity performance was not impaired during SMA stimulation, where tapping speed increased under validation conditions. Orofacial effects were limited and inconsistent, occurring mainly during stimulation outside the SMA and showing no significant spatial pattern. Conclusion: The expected somatotopic organization of the SMA could not be demonstrated using nrTMS. However, SMA-selective disruptions of upper extremity movements suggest a functional, rather than effector-specific, organization. The novel kinematic paradigm enabled detailed, objective analysis of movement phases and may benefit future TMS studies.
  • Decision tree enhancer (DTE): Improving decision trees with optimization
    (2026-04-22) Lim-Apo, Flávio Araújo; Oliveira, Fabricio; Hamacher, Silvio
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Decision trees are off-the-shelf machine learning models widely used for classification and regression tasks in medical, logistics, financial, and other critical areas where interpretability is a key factor. They can efficiently handle numerical and categorical variables, making them a versatile choice for various applications. However, traditional decision-tree training methods are based on greedy heuristics, which cannot provide guarantees regarding whether further improvements could be achieved. We propose Decision Tree Enhancer (DTE), which employs optimization as a post-training step to improve previously trained decision trees. Moreover, the proposed method precludes the need for a pre-processing step for continuous features such as discretization or bucketization, and can be applied regardless of the model used to first train the decision tree. Lastly, DTE’s mathematical programming formulation enables, for example, the consideration of recall thresholds and class prioritization. Tested on 63 classification datasets from the UCI Machine Learning Repository, using tree depths from 1 to 5, four time limits (1, 5, 10, and 30 s), and 5 randomized train-test splits for cross-validation, the proposed post-training step demonstrated superior performance over CART (Classification And Regression Tree), for both in- and out-of-sample data. With a 30 s time limit, DTE was able to improve the weighted recall in 83.2% of the datasets with an average improvement of 9.0% in training and 5.0% in testing.
  • DACN: Dual-Attention Convolutional Network for Hyperspectral Image Super-Resolution
    (2025) Muhammad, Usman; Laaksonen, Jorma
    A4 Artikkeli konferenssijulkaisussa
    2D convolutional neural networks (CNNs) have attracted significant attention for hyperspectral image super-resolution tasks. However, a key limitation is their reliance on local neighborhoods, which leads to a lack of global contextual understanding. Moreover, band correlation and data scarcity continue to limit their performance. To mitigate these issues, we introduce DACN, a dual-attention convolutional network for hyperspectral image super-resolution. Specifically, the model first employs augmented convolutions, integrating multi-head attention to effectively capture both local and global feature dependencies. Next, we infer separate attention maps for the channel and spatial dimensions to determine where to focus across different channels and spatial positions. Furthermore, a custom optimized loss function is proposed that combines L2 regularization with spatial-spectral gradient loss to ensure accurate spectral fidelity. Experimental results on two hyperspectral datasets demonstrate that the combination of multi-head attention and channel attention outperforms either attention mechanism used individually. The source codes are publicly available at: https://github.com/Usman1021/dual-attention.
  • Capturing individual variation in children’s electroencephalograms during nREM sleep
    (2026-01-01) Heikkinen, Verna; Merz, Susanne; Salmelin, Riitta; Vanhatalo, Sampsa; Lauronen, Leena; Liljeström, Mia; Renvall, Hanna
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Human brain dynamics are highly unique between individuals: functional neuroimaging studies have recently described functional features that can be used as neural fingerprints. However, the stability of these fingerprints is affected by aging and disease. As such, the stability of brain fingerprints may be a useful metric when studying normal and pathological neurodevelopment. Before examining clinically relevant deviations, the individual stability and variation of neuroimaging features across brain maturation in normally developing children need to be addressed with real clinical data. Here we applied Bayesian reduced-rank regression (BRRR) to extract low-dimensional representations of electroencephalography (EEG) power spectra measured during different non-REM sleep stages (N1 and N2) from 782 normally developing children aged between 6 weeks to 19 years. The representations learned within specific sleep stages successfully separated between subjects and generalized across sleep stages. Fingerprint stability increased with the age of the subjects. Compared to correlation-based fingerprinting methods, the BRRR model performed better, especially in fingerprinting across sleep stages, highlighting the usefulness of dimensionality reduction when the noise and signal of interest are correlated. While further studies are needed to address the possible non-linear maturation effects over developmental periods, our results demonstrate the existence of stable within-session neurofunctional fingerprints in pediatric populations.
  • Exploring motor behavior through transcranial magnetic stimulation : a comprehensive tutorial from the neurobiomechanics and motor control perspectives
    (2025-03-15) Garcia, Marco A.C.; de Nadai, Ana L.Y.; Moraes, Victor H.; Lopes, Tiago S.; Marchetti, Thaís C.; Betioli, Lucas S.; Souza, Victor H.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Transcranial Magnetic Stimulation (TMS) is a well-established method for probing corticospinal and intracortical processes, yet its application in biomechanics and motor control research often lacks methodological integration. This tutorial synthesizes fundamental and advanced procedures for applying TMS within neurobiomechanical frameworks, highlighting how neurophysiological measures relate to motor behavior. We detail practical considerations for recording motor evoked potentials (MEPs) using surface electromyography (sEMG), including electrode montage selection, coil positioning, neuronavigation, and data-processing approaches. We also outline protocols for single-and paired-pulse TMS, motor mapping, and TMS-EEG integration, emphasizing how each technique interfaces with biomechanical variables, including posture, muscle length, and task demands. By integrating foundational concepts and practical guidelines on TMS applications to movement-related mechanisms, this tutorial provides a structured guide for designing, executing, and interpreting studies at the intersection of neurophysiology, biomechanics, and motor control.
  • Synergistic Effects in Matrix-Embedded Alloy Nanoclusters : Advanced Type-I Photosensitizers for Theranostics
    (2026-02-11) Hosseiniyan, Negar; Castronovo, Pietro; Beaune, Gregory; Abdelrady, Eslam; Chen, Xi; Zhyvolozhnyi, Artem; Siddiqui, Hamza; Farhana, Jahan; Jiang, Hua; Makki, Minna; Cannas, Marco; Sciortino, Alice; Skovorodkin, Ilya; Samoylenko, Anatoliy; Vainio, Seppo J.; Messina, Fabrizio; Chandra, Sourov
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    A combination of biomedical imaging and photodynamic therapy (PDT) in a single nanomaterial would be a breakthrough in nanomedicine. However, devising a single photosensitizer capable of efficient PDT without requiring an external oxygen source under typically hypoxic tumor conditions, combined with high photostability, biocompatibility, and renal clearance, remains a challenge. Atomically precise ultrasmall (<2 nm) gold nanoclusters (AuNCs) are emerging as potential multifunctional biomedicines, encompassing imaging, diagnosis, and therapy in a single nanoplatform. Herein, we report bioderived cellulose nanocrystal-supported gold nanoclusters (CNC-AuNCs) with selective mono or multiheteroatom (Ag, Pd, and Pt) substitution at the core of the nanoclusters. The replacement of one or more gold atoms significantly modulates their emission wavelengths, photoluminescence quantum yields, as well as excited-state relaxation kinetics. These materials can easily penetrate the cells, accumulating in the cytoplasm and emitting bright luminescence. While the nanocomposites are highly biocompatible, they can produce reactive oxygen species (ROS) through the formation of free radicals (O2-· and ·OH) upon exposure of light. The synergistic effect of the light absorption by the matrix and the diverse excited-state relaxation pathways of the nanoclusters results in the efficient generation of ROS in variable concentrations, ultimately leading to the complete destruction of targeted cancer cells via Type-I photodynamic effect. The optimal ROS efficacy combined with minimal cytotoxicity suggests a universal strategy for developing strong PDT-I agents, paving the way for versatile nanomaterials in theranostic applications.
  • Many-body entanglement swapping protocol : Opportunities for distributed quantum computing
    (2026-01) Huhtanen, Santeri; Mafi, Yousef; Moghaddam, Ali G.; Ojanen, Teemu
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Sharing entangled pairs between nonsignaling parties via entanglement swapping constitutes a striking demonstration of the nonlocality of quantum mechanics and a crucial building block for future quantum technologies. In this work, we generalize pair-swapping methods by introducing a many-body entanglement swapping protocol, which allows two nonsignaling parties to share general many-body states along an arbitrary partitioning. The shared many-body state retains exactly the same Schmidt vectors as the target state and exhibits typically high fidelity, which approaches unity as the variance of the Schmidt coefficients vanishes. Moreover, we demonstrate how the three-party protocol can be generalized to many-body swapping networks, enabling a general many-body state sharing with unit fidelity via arbitrary number of intermediate nodes. This is achieved by replacing all but one of the unitary operations with those corresponding to the same Schmidt states but with a flattened spectrum, which also completely eliminates the need for postselection. We provide a proof of concept of the three-party protocol on real quantum hardware and discuss how it enables functionalities, such as fault-tolerant entanglement swapping and strategies for distributed quantum computing.
  • Artificial intelligence for web development : Perspectives from the industry
    (2026-03-01) Pohjalainen, Pyry; Vepsäläinen, Juho
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    As a field, web development is roughly 30 years old, and during this period, it has been transformed several times already as it has moved from static websites to dynamic web applications. Now, with the introduction of Artificial Intelligence (AI), the field is again at the cusp of a transformation as the latest AI tools might change how to develop for the web yet again. The objective of this study is to look into this phenomenon and understand how AI is changing web development. To achieve this task, we chose to use the sequential qualitative–quantitative design method that combines interviews with a survey to validate and expand our findings from the interviews. We found that AI is used by web developers to increase their development efficiency, as even the current tools are easy to use and access, although they come with several minor downsides, including AI not being able to understand complex logic, the need for validation of AI output, and suggested code that could potentially lead to security issues. While there are clear benefits to using AI tools for web development and AI proficiency is a vital skill for web developers, there are still open questions related to the quality of code produced by AI tools.
  • Nested R: Assessing the Convergence of Markov Chain Monte Carlo When Running Many Short Chains
    (2025-12) Margossian, Charles C.; Hoffman, Matthew D.; Sountsov, Pavel; Riou-Durand, Lionel; Vehtari, Aki; Gelman, Andrew
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Recent developments in parallel Markov chain Monte Carlo (MCMC) algorithms allow us to run thousands of chains almost as quickly as a single chain, using hardware accelerators such as GPUs. While each chain still needs to forget its initial point during a warmup phase, the subsequent sampling phase can be shorter than in classical settings, where we run only a few chains. To determine if the resulting short chains are reliable, we need to assess how close the Markov chains are to their stationary distribution after warmup. The potential scale reduction factor (R) over cap is a popular convergence diagnostic but unfortunately can require a long sampling phase to work well. We present a nested design to overcome this challenge and a generalization called nested (R) over cap. This new diagnostic works under conditions similar to (R) over cap and completes the workflow for GPU-friendly samplers. In addition, the proposed nesting provides theoretical insights into the utility of (R) over cap, in both classical and short-chains regimes.
  • A Gap-ETH-Tight Approximation Scheme for Euclidean TSP
    (2025-11-24) Kisfaludi-Bak, Sándor; Nederlof, Jesper; Węgrzycki, Karol
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We revisit the classic task of finding the shortest tour of n points in d-dimensional Euclidean space, for any fixed constant d ⩾ 2. We determine the optimal dependence on ɛ in the running time of an algorithm that computes a (1 + E)-approximate tour, under a plausible assumption. Specifically, we give an algorithm that runs in 2^o(1/E ^d-1) nlog n time. This improves the previously smallest dependence on ɛ in the running time (1/ε)^o(1/ε ^d-1)n log n of the algorithm by Rao and Smith (STOC 1998). We also show that a 2^o(1/ε ^d-1)poly(n) algorithm would violate the Gap-Exponential Time Hypothesis (Gap-ETH). Our new algorithm builds upon the celebrated quadtree-based methods initially proposed by Arora (J. ACM 1998), but it adds a new idea that we call sparsity-sensitive patching. On a high level this lets the granularity with which we simplify the tour depend on how sparse it is locally. We demonstrate that our technique extends to other problems, by showing that for Steiner Tree and Rectilinear Steiner Tree it yields the same running time. We complement our results with a matching Gap-ETH lower bound for Rectilinear Steiner Tree.