EPJ Quantum Technology最新文献

{"title":"Strategic governance of quantum supply chains: a criticality-based framework for risk, resilience, and data-driven foresight","authors":"Dongyoun Cho,&nbsp;Mauritz Kop,&nbsp;Min-Ha Lee","doi":"10.1140/epjqt/s40507-026-00486-y","DOIUrl":"10.1140/epjqt/s40507-026-00486-y","url":null,"abstract":"<div><p>Quantum technologies are moving from laboratory research to real-world deployment, but progress rests on narrow, fragile, globally dispersed supply chains. We introduce the Quantum Criticality Index (QCI)—a tri-axial assessment of supply risk, substitutability, and strategic significance—augmented with an artificial neural network (ANN)-based trend-detection module and a forward-looking stress-testing component. A case study of molybdenum (Mo), essential for superconducting circuits, single-photon detectors, cryogenic hardware, and other dual-use, security-sensitive systems, demonstrates how the QCI pinpoints chokepoints that could hinder hardware trajectories. Building on these diagnostics, we translate risk awareness into action through a governance framework that links the stages of diagnosis, decision, and delivery. By coupling structured indicators with predictive analytics, the QCI provides policymakers and industry with an evidence-based tool that translates diagnostics directly into an operational policy roadmap for allied procurement, intellectual property governance, targeted licensing, and verifiable, sustainable supply-chain assurance. Crucially, QCI-enabled supply chain resilience can function as a hardware-oriented complement to Post-Quantum Cryptography (PQC) migration, together forming a twin-pillar security framework in which physical supply-chain assurance underpins the quantum ecosystem, while PQC protects data integrity and critical infrastructure against “harvest-now, decrypt-later” campaigns and systemic risks.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00486-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737501","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":"Sagnac tractor atom interferometer on a photonic integrated circuit","authors":"Lefeng Zhou,&nbsp;Anne Graf,&nbsp;Georg Raithel","doi":"10.1140/epjqt/s40507-026-00485-z","DOIUrl":"10.1140/epjqt/s40507-026-00485-z","url":null,"abstract":"<div><p>We study the theory of, and propose an experimental design for, a Sagnac tractor atom interferometer based on a photonic integrated circuit (PIC). The atoms are trapped in counter-rotating azimuthal optical lattices, formed by interfering evanescent fields of laser modes injected into circular PIC waveguides. We develop quantum models for the radial and azimuthal dynamics of the interfering atoms in adiabatic frames, which provide computational efficiency. The theory is applied to an exemplary PIC, for which we first compute field modes and atom trapping potentials for ⁸⁷Rb. We then evaluate non-adiabaticity, fidelity, and sensitivity of the exemplary PIC.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00485-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642317","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":"The quantum technology job market: data driven analysis of 3641 job posts","authors":"Simon Goorney,&nbsp;Eleni Karydi,&nbsp;Borja Muñoz,&nbsp;Otto Santesson,&nbsp;Zeki Can Seskir,&nbsp;Ana Alina Tudoran,&nbsp;Jacob Sherson","doi":"10.1140/epjqt/s40507-026-00477-z","DOIUrl":"10.1140/epjqt/s40507-026-00477-z","url":null,"abstract":"<div><p>The rapid advancement of Quantum Technology (QT) has created a growing demand for a specialized workforce, spanning across academia and industry. This study presents a quantitative analysis of the QT job market by systematically extracting and classifying 3641 job postings worldwide. The classification pipeline leverages large language models (LLMs) whilst incorporating a “human-in-the-loop” validation process to ensure reliability. The research identifies key trends in regional job distribution, degree and skill requirements, and the evolving demand for QT-related roles. Findings reveal a strong presence of the QT job market in the United States and Europe, with increasing corporate demand for engineers, software developers, and PhD-level researchers. Despite growing industry applications, the sector remains in its early stages, dominated by large technology firms. However, there is some sign that there may be change to come, indicated by a strong presence of Bachelor and Master’s graduates in the workforce.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00477-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147558969","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":"Circuit-based vs. measurement-based quantum computing: a comparative analysis, layered metrics, and decision flow for approach selection","authors":"Harashta Tatimma Larasati,&nbsp;Byung-Soo Choi","doi":"10.1140/epjqt/s40507-026-00483-1","DOIUrl":"10.1140/epjqt/s40507-026-00483-1","url":null,"abstract":"<div><p>Circuit-based quantum computing (CBQC), also known as the gate model, is currently regarded as the leading paradigm for performing quantum computation and has garnered widespread interest due to its relatively better-established implementation and close intuitive resemblance to classical computation. However, an alternative model that solely utilizes single-qubit measurements on entangled states to perform computation, namely the measurement-based quantum computing (MBQC), has started to attract further research interest as it is deemed more naturally suited for certain quantum hardware architectures, though its actual implementation remains largely underexplored. Recently, there have been preliminary efforts to characterize the specific regimes in which MBQC may potentially be more advantageous compared to CBQC. Nevertheless, a more systematic assessment is necessary to assess the suitability of each model across a broader range of more practical cases. In this work, we present a detailed comparative analysis of CBQC and MBQC, beginning with reviewing the theoretical foundations of each model before highlighting its distinguishing features that set the two paradigms apart. Furthermore, building on previous work, we propose a generalized regime analysis that more accurately captures the conditions under which a given quantum algorithm is more favorably executed in MBQC or CBQC. Subsequently, we identify critical parameters that likely determine whether a quantum algorithm is better suited to CBQC or MBQC, categorizing detailed key factors and performance metrics into layers of quantum computation. Next, we propose a decision flow that, given specific hardware constraints and algorithm requirements, guides the selection to the most appropriate model, discussing suitability in two representative worked examples of quantum algorithm applications: Quantum Fourier Transform (QFT) and Variational Quantum Algorithm (VQE). Last, we discuss the potential to combine both models as a hybrid approach to leverage the best of both worlds and explore its benefits for practical quantum computing applications.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00483-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147607140","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":"Toward practical quantum encryption in phase space: simulated QPSK and 16-QAM with dynamic displacement operators","authors":"Chenyu Zhang,&nbsp;Randy Kuang,&nbsp;Jian Xu,&nbsp;Kai Wen,&nbsp;Tianyi Wu,&nbsp;Zhenrong Zhang,&nbsp;Chen Dong","doi":"10.1140/epjqt/s40507-026-00480-4","DOIUrl":"10.1140/epjqt/s40507-026-00480-4","url":null,"abstract":"<div><p>Building upon the theoretical framework of Dynamic Displacement Operators (DDO) introduced in Ref. (Kuang, in Acad Quantum 2, 2025, https://doi.org/10.20935/AcadQuant7462), we present a simulation validation of a quantum-enhanced encryption scheme for coherent optical communication systems in phase space. The method integrates random phase shift operators (PSOs) and displacement operators (DOs) to dynamically manipulate information symbols on a symbol-by-symbol basis, enabling secure physical-layer encryption. Simulation results confirm that accurate decryption is only possible with the correct operator pair; any mismatch in displacement or phase parameters leads to bit error rates approaching 50%, effectively blocking unauthorized access. We further compare the performance of unencrypted transmission with various quantum-enhanced physical-layer security (QEPS) configurations over different fiber lengths, and explicitly validate the scalability of the proposed scheme by simulating a higher-order Quantum Permutation Pad (QPP) with a depth of <span>(m = 2)</span> for 16-QAM. The results validate the robustness of the proposed DDO-based scheme against partial or incorrect decryption attempts, underscoring its potential for securing data transmission in classical optical networks.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00480-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147607141","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":"An efficient and secure multi-party convex hull protocol using quantum secret commitment","authors":"Wen-Jie Liu,&nbsp;Solomon Danquah Danso","doi":"10.1140/epjqt/s40507-026-00482-2","DOIUrl":"10.1140/epjqt/s40507-026-00482-2","url":null,"abstract":"<div><p>Convex hull computation is a fundamental problem in secure multi-party computational geometry (SMCG), classified under secure multi-party computation (SMC) for finding the convex hull of a set of points. Existing quantum solutions largely depend on quantum homomorphic encryption (QHE), which introduces significant computational overhead due to frequent key updates by a trusted third party (TTP). Furthermore, most current protocols lack a mechanism for input commitment, making them vulnerable to post-computation input tampering or denial by the TTP. To overcome these limitations, we propose an efficient convex hull protocol that utilizes quantum secret commitment (QSC) as a more secure alternative to QHE. Our protocol enables a designated party (the committer) to securely commit to input values in a manner that guarantees both binding (no post-hoc alteration) and hiding (input secrecy). We introduce a novel value comparison protocol within an Ideal Quantum K-Party model, ensuring privacy-preserving convex hull computation without reliance on QHE. Rigorous security analysis demonstrates significant improvements in computational efficiency and resilience against quantum adversaries. Our protocol represents a pivotal advancement for quantum-secure multi-party computations and lays the groundwork for scalable, future-proof privacy-preserving geometry in quantum computing contexts.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00482-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147607015","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":"EAQAS: Embedding-Aware Quantum Architecture Search via cross-attention fusion and hierarchical representation learning","authors":"Jiawen Dai,&nbsp;Jialiang Gu,&nbsp;Raymond Ho,&nbsp;Gary Man-Tat Man,&nbsp;Kwok Tai Chui,&nbsp;Kevin Hung","doi":"10.1140/epjqt/s40507-026-00478-y","DOIUrl":"10.1140/epjqt/s40507-026-00478-y","url":null,"abstract":"<div><p>Existing quantum architecture search (QAS) methods typically treat quantum data embedding and circuit structures as independent components, leading to inefficient search processes and limited performance. We propose EAQAS, an embedding-aware QAS framework that explicitly models the joint representation of embedding operations and quantum gates using a Hierarchical Variational Graph Autoencoder (H-VGAE) with bi-directional cross-attention fusion. The framework integrates RepCap-based filtering for search space pruning, dual-branch encoders for modality-specific representation learning, and Bayesian optimization in the learned latent space. On binary classification tasks using MNIST and WDBC, EAQAS achieves accuracies of 99.28% and 97.01%, respectively. RepCap filtering at moderate thresholds (<span>(tau =0.3)</span>–0.5) accelerates search by 1.43–1.74× while fully preserving accuracy. Ablation studies confirm that cross-modal reconstruction is the most critical component, with its removal causing a 5.16% average performance drop. This work demonstrates that embedding-aware representation learning can enhance automated quantum circuit design under NISQ-compatible constraints.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00478-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147340218","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":"Quantum related-key attacks on Feistel-like ciphers","authors":"Hong-Wei Sun,&nbsp;Long Zhang,&nbsp;Dan-Dan Li,&nbsp;Zhen-Qiang Li,&nbsp;Rong-Xue Xu,&nbsp;Ke-Jia Zhang","doi":"10.1140/epjqt/s40507-026-00481-3","DOIUrl":"10.1140/epjqt/s40507-026-00481-3","url":null,"abstract":"<div><p>Quantum attacks employing superposition queries (Q2 model) have been demonstrated to compromise numerous classically secure block-cipher constructions. These attacks embed the target encryption structure into a period-finding problem, which dedicated quantum algorithms, including the Simon and BV algorithms, can solve. After restoring the secret state, attackers can launch an attack by recovering the key (the secret state contains key information) or distinguishing it from random permutations.</p><p>In this paper, we investigate the quantum security of Feistel-like ciphers in a related-key setting. For several constructions, we demonstrate how to define a periodic function that can be evaluated using the Simon algorithm with only <span>(O(n))</span> quantum queries to the encryption oracle, where <i>n</i> represents the block size. This enables secret-state recovery attacks on Type-1/2 generalized Feistel schemes, as well as key-recovery attacks on the Feistel-FK and Misty L-KF constructions. All these attacks achieve an exponential reduction in query complexity compared to the best known classical or quantum methods.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00481-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559761","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":"Performance characterization of a multi-module quantum processor with static inter-chip couplers","authors":"Graham J. Norris,&nbsp;Kieran Dalton,&nbsp;Dante Colao Zanuz,&nbsp;Alexander Rommens,&nbsp;Alexander Flasby,&nbsp;Mohsen Bahrami Panah,&nbsp;François Swiadek,&nbsp;Colin Scarato,&nbsp;Christoph Hellings,&nbsp;Jean-Claude Besse,&nbsp;Andreas Wallraff","doi":"10.1140/epjqt/s40507-026-00469-z","DOIUrl":"10.1140/epjqt/s40507-026-00469-z","url":null,"abstract":"<div><p>Three-dimensional integration technologies such as flip-chip bonding are a key prerequisite to realize large-scale superconducting quantum processors. Modular architectures, in which circuit elements are spread over multiple chips, can further improve scalability and performance by enabling the integration of elements with different substrates or fabrication processes, by increasing the fabrication yield of completed devices, and by physically separating the qubits onto distinct modules to avoid correlated errors mediated by a common substrate. We present a design for a multi-chip module comprising one carrier chip and four qubit modules. Measuring two of the qubits, we analyze the readout performance, finding a mean three-level state-assignment error of <span>(9 times 10^{-3})</span> in 200 ns. We calibrate single-qubit gates and measure a mean simultaneous randomized benchmarking error of <span>(6 times 10^{-4})</span>, consistent with the coherence times of the qubits. Using a wiring-efficient static inter-module coupler featuring galvanic inter-chip transitions, we demonstrate a controlled-Z two-qubit gate in 100 ns with an error of <span>(7 times 10^{-3})</span> extracted from interleaved randomized benchmarking. Three-dimensional integration, as presented here, will continue to contribute to improving the performance of gates and readout as well as increasing the qubit count in future superconducting quantum processors.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00469-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559609","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":"Correction: Analog QAOA with Bayesian optimisation on a neutral atom QPU","authors":"Simone Tibaldi,&nbsp;Lucas Leclerc,&nbsp;Davide Vodola,&nbsp;Edoardo Tignone,&nbsp;Elisa Ercolessi","doi":"10.1140/epjqt/s40507-026-00479-x","DOIUrl":"10.1140/epjqt/s40507-026-00479-x","url":null,"abstract":"","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"13 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjqt/s40507-026-00479-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338455","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}