EPJ Quantum Technology最新文献

{"title":"Academic and demographic predictors of high school student knowledge of classical physics, quantum physics, and quantum computing in university-based outreach","authors":"Robert De La Cruz,&nbsp;Angela M. Kelly,&nbsp;Tzu-Chieh Wei,&nbsp;Dominik Schneble","doi":"10.1140/epjqt/s40507-026-00515-w","DOIUrl":"10.1140/epjqt/s40507-026-00515-w","url":null,"abstract":"<div><p>With the current growth in quantum information science and technology (QIST) industrial innovation, there is an increasing need to prepare precollege students for post-secondary QIST study and careers. This study examined high school student outcomes from a QIST outreach program held at both a research university and an informal science institution in the United States. The pre-/post-research design incorporated a newly developed <i>QIST Integration Framework</i> that included elements of science, technology, engineering, and mathematics (STEM) integration frameworks as well as conceptual change theories. The program was structured to address the initially counterintuitive, abstract nature of QIST concepts, and its applications, through multiple representations, career awareness modules, and exposure to role models. The program featured lectures, simulations, demonstrations, and hands-on experiences in classical and quantum physics and quantum computing. Students in grades 10-12 (<span>(N=209)</span>) attended one of six 25-hour outreach programs over three summers (2023-2025). They improved their overall QIST knowledge as well as knowledge in each subdomain of classical physics, quantum physics, and quantum computing, all with large effect sizes. Analysis of variance and analysis of covariance indicated that there were no differences in QIST knowledge outcomes when considering student gender, ethnicity, grade level, and prior mathematics, physics, chemistry, and computer science course completion. However, students who had completed at least one science research course outperformed those who had not completed this course, with a small effect size. This informal summer outreach program demonstrates promise in promoting QIST subdomain knowledge, skills, and applications, which will prepare students for this critical emerging field that advances technological solutions for immediate and future global challenges.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00515-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simple tunable phase-locked lasers for quantum technologies","authors":"Nicola Agnew,&nbsp;David Lowit,&nbsp;Aidan S. Arnold","doi":"10.1140/epjqt/s40507-026-00516-9","DOIUrl":"10.1140/epjqt/s40507-026-00516-9","url":null,"abstract":"<div><p>In a wide range of quantum technology applications, ranging from atomic clocks to the creation of ultracold samples for atom interferometry, optimal laser sources are critical. In particular, two phase-locked laser sources with a precise difference frequency are needed for efficient coherent population trapping (CPT) clocks, gray molasses laser cooling, or driving Raman transitions. Here we show how a simple cost-effective laser diode can selectively amplify only one sideband of a fiber-electrooptically-modulated seed laser to produce moderate-power phase-locked light with sub-Hz relative linewidth and tunable difference frequencies up to <span>(approx 15text{ GHz})</span>. The architecture is readily scalable to multiple phase-locked lasers and could conceivably be used for future on-chip compact laser systems for quantum technologies.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13272608/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148275618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continuous-variable photonic quantum extreme learning machines for fast collider-data selection","authors":"Benedikt Maier,&nbsp;Michael Spannowsky,&nbsp;Simon Williams","doi":"10.1140/epjqt/s40507-026-00507-w","DOIUrl":"10.1140/epjqt/s40507-026-00507-w","url":null,"abstract":"<div><p>We study continuous-variable photonic quantum extreme learning machines as fast, low-overhead front-ends for collider data processing. Data is encoded in photonic modes through quadrature displacements and propagated through a fixed-time Gaussian quantum substrate. The final readout occurs through Gaussian-compatible measurements to produce a high-dimensional random feature map. Only a linear classifier is trained, using a single logistic regression, so retraining is fast, and the optical path and detector response set the analytical and inference latency. We evaluate this architecture on two representative classification tasks, top-jet tagging and Higgs-boson identification, with parameter-matched multi-layer perceptron (MLP) baselines. Using standard public datasets and identical train, validation, and test splits, the photonic Quantum Extreme Learning Machine (QELM) outperforms an MLP with two hidden units for all considered training sizes, and matches or exceeds an MLP with ten hidden units at large sample sizes, while training only the linear readout. These results indicate that Gaussian photonic extreme-learning machines can provide compact and expressive random features at fixed latency. The combination of deterministic timing, rapid retraining, low optical power, and room temperature operation makes photonic QELMs a credible building block for online data selection and even first-stage trigger integration at future collider experiments.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00507-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study of high-(J_{c}) and low-(J_{c}) SFQ microwave generators for transmon control","authors":"Hongxiang Shen,&nbsp;Wenhui Luo,&nbsp;Nobuyuki Yoshikawa","doi":"10.1140/epjqt/s40507-026-00514-x","DOIUrl":"10.1140/epjqt/s40507-026-00514-x","url":null,"abstract":"<div><p>Scalability of superconducting quantum processors is increasingly constrained by the thermal load and wiring overhead associated with room-temperature control hardware. Cryogenic control interfaces based on single-flux-quantum (SFQ) logic offer a potential route to alleviating these bottlenecks, although their dissipation depends sensitively on the Josephson-junction critical current and the underlying fabrication process. In this work, we comparatively investigate SFQ-synthesized microwave generators implemented in high- and low-critical-current processes, and evaluate their suitability for transmon qubit control through a combination of experimental characterization and hybrid QuTiP–JoSIM analysis. By modulating SFQ pulse intervals, we synthesize coherent microwave drives and obtain single-qubit gate fidelities above 99.9% at 10 mK in QuTiP-based simulations for both implementations. The low-<span>(J_{mathrm{c}})</span> implementation exhibits reduced phase-noise-induced error, achieves higher gate fidelity within its valid bias window, and shows improved robustness against frequency detuning, while the high-<span>(J_{mathrm{c}})</span> implementation maintains a lower broadband noise floor. Using an explicit model of thermal dissipation and circuit footprint, we further estimate the integration limits of cryogenic control channels. The results show that reducing the switching current substantially relaxes the cooling-budget constraint and increases the number of channels that can be deployed simultaneously. These results clarify the trade-offs associated with implementing SFQ microwave generators in different fabrication processes and provide practical guidance for the design of scalable cryogenic qubit-control interfaces.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00514-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A four-dimensional controllable multi-wing hyperchaotic system: design, nonlinear dynamics analysis, and application to quantum key distribution","authors":"Xin Huang,&nbsp;Qun Ding","doi":"10.1140/epjqt/s40507-026-00512-z","DOIUrl":"10.1140/epjqt/s40507-026-00512-z","url":null,"abstract":"<div><p>Chaotic systems, as a core research topic in nonlinear science, have significant application value in information security and communication encryption. This paper proposes a novel four-dimensional hyperchaotic multi-wing system. By introducing a periodic nonlinear coupling function <span>(cos(omega w))</span> and extending the state variables, an autonomous system with rich and complex dynamic behaviors is constructed. Theoretical analysis indicates that this system possesses infinitely countable equilibrium points, exhibiting a grid-like distribution of saddle-focus structures, providing the mathematical foundation for the formation of multi-wing attractors. Hyperchaotic characteristics of the system under specific parameters are verified through numerical simulations. Furthermore, the regulatory mechanism of system parameters on dynamic behaviors is analyzed, revealing the complete evolution path from periodic to chaotic states. An equivalent chaotic circuit is designed based on the Multisim platform, achieving circuit simulation and implementation of the multi-wing attractors. Finally, the potential application of the system in Quantum Key Distribution for key expansion and noise masking is preliminarily explored. This study provides theoretical support and an experimental basis for the construction, analysis, and engineering application of high-dimensional chaotic systems.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00512-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148172718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-dimensional GHZ-based multi-party quantum key agreement: rigorous security, fairness, and loss tolerance","authors":"Hamza Sohail,&nbsp;Burhan Ul Islam Khan,&nbsp;Nur Fatin Liyana Mohd Rosely,&nbsp;Khang Wen Goh,&nbsp;Dwi Sudarno Putra,&nbsp;Abdul Raouf Khan,&nbsp;Mesith Chaimanee","doi":"10.1140/epjqt/s40507-026-00510-1","DOIUrl":"10.1140/epjqt/s40507-026-00510-1","url":null,"abstract":"<div><p>Multi-party quantum key agreement (MQKA) enables a group of mutually untrusted users to jointly establish a secret key with equal influence, a capability not provided by two-party quantum key distribution (QKD) and increasingly relevant for securing resilient infrastructure such as quantum-enabled smart grid networks and distributed cyber-physical systems. We present a high-dimensional Greenberger-Horne-Zeilinger (GHZ)-based MQKA that simultaneously targets rigorous security, provable fairness, and practical loss tolerance. The protocol distributes an <i>N</i>-partite <i>d</i>-level GHZ state in a star (with an optional star-of-stars hierarchy for large <i>N</i>) and maps each user’s contribution to local <span>(X_{d}^{a} Z_{d}^{b})</span> operations. A commit-then-reveal layer makes inputs binding and hiding, yielding equal influence fairness over <span>(mathbb{Z}_{d})</span> with a strict fair-abort guarantee. Composable secrecy is established via entropy bounds and a Devetak-Winter-style key rate analysis, strengthened by test-round statistics; we connect Mermin/Svetlichny-type correlators to min-entropy lower bounds and incorporate full leakage accounting and finite-key penalties. We model depolarizing, shift/phase (Weyl), amplitude-damping, erasures, detector efficiency, and dark counts, and derive closed-form mappings from device parameters to symbol/phase errors. Monte Carlo studies confirm that <span>(d&gt;2)</span> expands the positive-rate region and reduces the global survival required for a given throughput compared with qubit GHZ MQKA under identical conditions. We discuss potential photonic realizations (time-bin or frequency-bin encoding, discrete Fourier transform networks, and superconducting nanowire detectors) and architectural pathways toward larger <i>N</i> via hierarchical clustering, while acknowledging the significant technological challenges that would need to be overcome to realize high-dimensional multipartite entanglement experimentally. Overall, the scheme delivers higher efficiency per entangled state, rigorous fairness, and composable security with realistic noise and loss, addressing key gaps in current MQKA designs for resilient infrastructure.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00510-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Hybrid Quantum–Classical Machine Learning Framework for Black Carbon Forecasting","authors":"Isaac Oliva-González,&nbsp;Lucy T. González,&nbsp;Oscar D. Lara-Montaño,&nbsp;Aldo I. Ramirez,&nbsp;Alberto Mendoza,&nbsp;Ilse María Hernández-Romero","doi":"10.1140/epjqt/s40507-026-00511-0","DOIUrl":"10.1140/epjqt/s40507-026-00511-0","url":null,"abstract":"<div><p>Black carbon (BC) is a critical short-lived climate pollutant with severe health and climate impacts, yet forecasting its hourly dynamics remains challenging due to nonlinear interactions between meteorological conditions and co-emitted pollutants. Accurate forecasting is particularly relevant in regions facing persistent air quality issues, where BC frequently exceeds recommended limits and poses significant risks to public health. This study develops a data-driven forecasting framework that integrates ensemble learning with hybrid quantum–classical neural architectures, benchmarked using 8760 hourly records from Santa Catarina in the Monterrey Metropolitan Area (Mexico). Ensemble methods provided the most reliable baseline, with XGBoost (<span>(mathrm{R}^{2} = 0.80)</span>, RMSE = 614.32 ng m⁻³) and CatBoost (<span>(mathrm{R}^{2} = 0.80)</span>, RMSE = 614.06 ng m⁻³) effectively capturing pollutant–meteorology dependencies. In contrast, a purely quantum neural network underperformed (<span>(mathrm{R}^{2} = 0.62)</span>), whereas its hybrid quantum–classical counterpart improved predictive accuracy (<span>(mathrm{R}^{2} = 0.72)</span>) and exhibited more stable convergence, highlighting the benefits of combining quantum representations with classical optimization under current hardware constraints. Dimensionality reduction through Principal Component Analysis (six components retaining 91% of variance) had a limited effect on ensemble models but reduced the ability of neural and quantum architectures to capture extreme pollution events above 3000 ng m⁻³. These findings elucidate how machine learning architectures represent the temporal dynamics of short-lived climate pollutants and support the development of adaptive early-warning systems for air quality management. The proposed hybrid framework provides a reproducible and extensible basis for applying quantum computing techniques to environmental forecasting, establishing a methodological foundation for future quantum–environmental research.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00511-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148172869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral phase encoding for quantum kernel methods","authors":"Pablo Herrero Gómez,&nbsp;Antonio Jimeno Morenilla,&nbsp;David Muñoz-Hernández,&nbsp;Higinio Mora Mora","doi":"10.1140/epjqt/s40507-026-00509-8","DOIUrl":"10.1140/epjqt/s40507-026-00509-8","url":null,"abstract":"<div><p>Quantum kernel methods are promising for near-term quantum machine learning, yet their behavior under data corruption remains insufficiently understood. We analyze how quantum feature constructions degrade under controlled additive noise.</p><p>We introduce <i>Spectral Phase Encoding</i> (SPE), a hybrid construction combining a discrete Fourier transform (DFT) front-end with a diagonal phase-only embedding. Within a unified framework, we compare the resulting DFT-based quantum-kernel pipeline (<span>QK-DFT</span>) against alternative quantum variants based on principal component analysis (PCA) and random projections (RP), as well as classical support vector machine (SVM) baselines, under identical clean-data hyperparameter selection. Robustness is quantified via dataset fixed-effects regression with wild cluster bootstrap inference across heterogeneous real-world datasets.</p><p>Across the matched quantum family, DFT-based preprocessing yields the smallest degradation rate as noise increases, with statistically supported slope differences relative to PCA and RP. Compared with classical baselines, <span>QK-DFT</span> shows degradation comparable to linear SVM and more favorable than radial basis function (RBF) SVM under the present tuning protocol. Hardware experiments further confirm that the resulting overlap-estimation primitive remains executable and numerically stable. Taken together, these results support a robustness-first view of quantum kernel evaluation and show that, within the controlled pipeline family studied here, structure-aligned spectral preprocessing combined with a shared diagonal quantum embedding can yield slower degradation under corruption.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00509-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148172870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HCQNSC: a hybrid classical-quantum neural network for text sentiment classification","authors":"Tingyu Liu,&nbsp;Ying Li,&nbsp;Jingtao Wang,&nbsp;Yun Pan","doi":"10.1140/epjqt/s40507-026-00506-x","DOIUrl":"10.1140/epjqt/s40507-026-00506-x","url":null,"abstract":"<div><p>Combining variational quantum circuits with classical neural network models is a potential direction for quantum natural language processing (QNLP) in the NISQ (Noisy Intermediate-Scale Quantum) era. We propose a hybrid classical-quantum neural network that enhances a transformer architecture in two key ways: first, by incorporating optimized variational quantum circuits into the self-attention and multilayer perceptron components, and second, by integrating a hybrid convolutional module for effective dimensionality reduction which can reduce the quantum resources required for subsequent layers and enhances the model’s trainability by mitigating issues like the barren plateau phenomenon, thus making it feasible to construct a deeper and more powerful network architecture. Our experiments on three widely-used sentiment analysis datasets demonstrate that the proposed model achieves comparable or even superior performance in terms of accuracy and F1 score compared to classical transformer-based sentiment classification models with similar structures, while reducing the number of parameters through the utilization of quantum advantages.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00506-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient gate reordering for Distributed Quantum Compiling in data centers","authors":"Riccardo Mengoni,&nbsp;Walter Nadalin,&nbsp;Mathys Rennela,&nbsp;Jimmy Rotureau,&nbsp;Tom Darras,&nbsp;Julien Laurat,&nbsp;Eleni Diamanti,&nbsp;Ioannis Lavdas","doi":"10.1140/epjqt/s40507-026-00513-y","DOIUrl":"10.1140/epjqt/s40507-026-00513-y","url":null,"abstract":"<div><p>Just as classical computing relies on distributed systems, the quantum computing era requires new kinds of infrastructure and software tools. Quantum networks will become the backbone of hybrid, quantum-augmented data centers, in which quantum algorithms are distributed over a local network of quantum processing units (QPUs) interconnected via shared entanglement. In this context, it is crucial to develop methods and software that minimize the number of inter-QPU communications. Here we describe key features of the quantum compiler <i>araQne</i>, which is designed to minimize distribution cost, measured by the number of entangled pairs required to distribute a monolithic quantum circuit using gate teleportation protocols. In particular, we focus on the crucial role of a preprocessing stage based on gate reordering strategies, achieving a notable reduction of the distribution cost compared to a baseline approach.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00513-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148173023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}