Quantum Information Processing最新文献

{"title":"Afterpulse analysis for practical phase-matching quantum key distribution","authors":"Chuan-Hao Shu,&nbsp;Yu-Hang Zhao,&nbsp;Zhang Wen,&nbsp;Meng-Rui Sun,&nbsp;Jian-Rong Zhu,&nbsp;Chun-Mei Zhang,&nbsp;Hong-Wei Li","doi":"10.1007/s11128-026-05364-1","DOIUrl":"10.1007/s11128-026-05364-1","url":null,"abstract":"<div><p>Twin-field quantum key distribution (TF-QKD) enables secure communication over high transmission losses, which can overcome the linear key-rate constraint without quantum repeaters. As an important variant of TF-QKD, phase-matching QKD (PM-QKD) has garnered considerable attention due to the advantage of preparing states in only one basis for both key generation and parameter estimation. To advance the practical deployment of PM-QKD systems, single-photon avalanche detectors (SPADs) represent a superior choice owing to their compact size, low cost, and high robustness. Nevertheless, the afterpulses inherent in SPADs can introduce unexpected avalanches, which, if omitted, will make the observables in the numerical simulation deviate from those in the actual experiment. Here, we develop an afterpulse-compatible model to address this issue. Simulation results demonstrate that the afterpulses degrade the secret key rate and transmission loss of PM-QKD. Furthermore, to alleviate the performance degradation under the afterpulse effect, we apply the advantage distillation method to enhance the key rate and tolerable transmission loss.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One-shot achievable rate regions for classical and quantum Sgarro coding","authors":"Xiaomin Liu,&nbsp;Zhengjun Xi","doi":"10.1007/s11128-026-05361-4","DOIUrl":"10.1007/s11128-026-05361-4","url":null,"abstract":"<div><p>We study one-shot source coding with side information available at two decoders. We first establish one-shot achievable rate bounds for the classical setting by combining smooth information quantities with the one-shot maximal simultaneous code lemma. We then extend the framework to classical source coding with full quantum side information at two decoders. For this setting, we establish a quantum version of the maximal simultaneous code lemma. Finally, we consider a quantum helper variant in which the decoders do not directly access the quantum systems but instead receive coded outcomes from the helpers. By one-shot measurement compression, we derive an achievable rate region. In the asymptotic i.i.d. limit, these one-shot bounds recover the corresponding asymptotic rate bounds.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum statistical learning theory: concepts, regimes, and open problems","authors":"Ferhat Ozgur Catak","doi":"10.1007/s11128-026-05356-1","DOIUrl":"10.1007/s11128-026-05356-1","url":null,"abstract":"<div><p>Statistical learning theory provides the mathematical foundations for understanding generalization from finite data. As quantum computing and quantum machine learning continue to develop, there is increasing interest in whether analogous principles can be formulated for learning settings involving quantum data, quantum models, or quantum computation. This paper offers an introductory perspective on quantum statistical learning theory. We begin by recalling the basic ideas of classical statistical learning theory, including empirical risk minimization, hypothesis classes, generalization, and sample complexity, and then discuss how these concepts must be adapted in the quantum setting. In particular, we distinguish between learning with classical data using quantum algorithms, learning with quantum models, and learning directly from quantum data. We then develop a resource-sensitive description that separates population risk, ideal empirical risk, and finite-shot empirical risk. This distinction makes explicit the different roles of training sample size and measurement budget. For a binary measurement-based classifier, we derive a finite-shot condition relating the required measurement budget to the sample size, confidence level, and classification margin. We further discuss how finite-sample generalization, finite-measurement estimation, and hardware imperfections can be represented as distinct contributions to experimentally observed learning performance. We conclude with a discussion of open problems and directions toward a more unified theory of generalization and learnability in quantum learning.\u0000</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11128-026-05356-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Delayed information and quantum entanglement in Cournot duopoly: a protocol-invariant boundary for oscillatory instability","authors":"Luca Guerrini,&nbsp;Stefania Ragni","doi":"10.1007/s11128-026-05359-y","DOIUrl":"10.1007/s11128-026-05359-y","url":null,"abstract":"<div><p>We study a continuous-time quantum Cournot duopoly with isoelastic demand and delayed marginal-profit adjustment. A unified representation covers the Li–Du–Massar and Frąckiewicz protocols and separates protocol effects from cost asymmetry. We derive the interior quantum Nash equilibrium, establish positivity, global existence, and boundedness, and obtain the exact characteristic equation. Writing <span>(m=c_2/c_1)</span>, the equilibrium is stable for every finite delay whenever <span>(3-2sqrt{2}le mle 3+2sqrt{2})</span>, whereas a finite critical delay exists when <span>(m&lt;3-2sqrt{2})</span> or <span>(m&gt;3+2sqrt{2})</span>. In the latter regime, a simple conjugate pair crosses the imaginary axis transversally, identifying the onset of an oscillatory instability. Numerical simulations are consistent with the resulting oscillatory dynamics beyond the stability threshold. The existence of a finite stability threshold depends only on relative marginal costs; entanglement and protocol choice determine its numerical location. Root continuation further supports the analytical results.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum games and economics through teleportation","authors":"Kazuki Ikeda","doi":"10.1007/s11128-026-05341-8","DOIUrl":"10.1007/s11128-026-05341-8","url":null,"abstract":"<div><p>Quantum Information Science and Technology (QIST) is reshaping computing and communication, with wide-ranging implications for economics, from market structures to strategic decision-making. Building on these breakthroughs, this paper bridges quantum concepts and economics through quantum energy teleportation (QET)—a protocol enabling energy transfer as a quantum commodity among multiple agents. By incorporating superposition, entanglement, and measurement into classical economic models, we derive new game-theoretic strategies and equilibria unreachable in purely classical frameworks. We delve into monopoly, location games, contestable markets, perfect competition, and duopoly, introducing quantum variations of traditional Bertrand and Cournot models. Moreover, we address moral hazard, free riding, and other public goods challenges through a quantum lens, unveiling unconventional strategies that transcend classical limits. Building on these insights, we incorporate entangled resources into matching theory, opening up entirely new possibilities for achieving stable and optimal allocations. These findings foreshadow a nascent field of <i>Quantum Information Economics</i>.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stronger hierarchy between local quantum uncertainty and local quantum fisher information potentials","authors":"Qing-Long Tian,&nbsp;You-Neng Guo","doi":"10.1007/s11128-026-05349-0","DOIUrl":"10.1007/s11128-026-05349-0","url":null,"abstract":"<div><p>Inspired by previous studies on entanglement potentials as measures of nonclassicality for single-mode optical states, this work introduces two novel quantifiers based on local quantum uncertainty potential (LQUP) and local quantum Fisher information potential (LQFIP). These two related potentials are employed to characterize the nonclassical nature of single-mode optical fields beyond conventional entanglement-based measures and exhibit similar trends. In particular, the relationship between LQFIP and LQUP is revealed. The exact lower and upper bounds of LQFIP versus LQUP are obtained for a specific class of nonclassical states, and the respective states which saturate those bounds are also characterized. This allows us to establish a strong hierarchy of nonclassicality for single-qubit optical states, mapped directly from the hierarchy of two-qubit quantum correlations. Our findings not only provide new tools for quantifying nonclassicality but also deepen the understanding of quantum resources in optical systems, with potential applications in quantum metrology and information processing.\u0000</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data-driven Hamiltonian correction of transmon qubits","authors":"John George Francis,&nbsp;Anil Shaji","doi":"10.1007/s11128-026-05350-7","DOIUrl":"10.1007/s11128-026-05350-7","url":null,"abstract":"<div><p>We obtain correction terms for the standard Hamiltonian of 2 transmons driven by microwaves in cross-resonance. Data are obtained from a real transmon system, namely ibm_kyiv on the IBM quantum platform. Various data points obtained correspond to different microwave amplitudes and evolution times. We have an ansatz for the correction term and a correction operator whose matrix elements are parameters to be optimized for. We use adjoint sensitivity and gradient descent to obtain these parameters. Since the ansatz itself is not unique, we obtain an equivalence class of effective corrections through the methods we developed. We see a good fit in the predictions from the corrected Hamiltonian and hardware results. The average absolute error in predicting the resultant probability was reduced from a worst case value of 0.48 in the uncorrected Hamiltonian to below 0.05 in the correction, demonstrating the effectiveness of scientific machine learning for fine tuning theoretical models to faithfully reproduce observed data on time evolution multiple qubit systems.\u0000</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Boolean functions related to two-party nonlocal games for biased inputs","authors":"Jyotirmoy Basak,&nbsp;Anurag Ghosh","doi":"10.1007/s11128-026-05346-3","DOIUrl":"10.1007/s11128-026-05346-3","url":null,"abstract":"<div><p>The CHSH game is the most extensively studied two-party nonlocal game with binary inputs and outputs, while Basak et al. [1] recently identified additional games of this type that exhibit quantum advantage under uniform inputs. Motivated by the practical difficulty of generating perfectly unbiased inputs, we investigate these games under symmetric biased input distributions. We determine the optimal classical success probabilities and analyze the corresponding quantum success probabilities within a restrictive family of quantum strategies. Our results show that quantum advantage persists over suitable ranges of input bias even within this restricted quantum strategy family, with both the optimal strategies and the quantum advantage depending on the input bias. Moreover, for all considered games, the quantum advantage is maximized at the uniform input distribution within the considered restricted quantum strategy family.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combining elliptic-curve cryptography and quantum-computing approach to secure cloud computing against distributed denial-of-service attacks","authors":"Rachid Beghdad","doi":"10.1007/s11128-026-05344-5","DOIUrl":"10.1007/s11128-026-05344-5","url":null,"abstract":"<div><p>The rapid proliferation of cloud computing environments has introduced significant security vulnerabilities, with distributed denial-of-service (DDoS) attacks emerging as one of the most disruptive and economically damaging threats. Traditional cryptographic mechanisms, while effective against many classical attack vectors, face mounting challenges from the advent of quantum computing, whose exponential processing capabilities threaten to render existing public key cryptosystems obsolete. This paper proposes a novel hybrid security framework that integrates elliptic-curve cryptography (ECC) with quantum-resistant algorithms to deliver robust, scalable protection for cloud infrastructures against DDoS attacks. ECC is leveraged for its exceptional computational efficiency and compact key sizes, making it highly suitable for resource-constrained cloud environments. Simultaneously, quantum-computing principles—specifically quantum key distribution (QKD) and post-quantum lattice-based cryptographic schemes—are incorporated to future-proof the framework against next-generation adversarial threats. The proposed architecture introduces a multi-layered defense mechanism encompassing real-time traffic anomaly detection, cryptographically authenticated session management, and distributed quantum-secured communication channels. Theoretical analysis and simulated evaluations across a 10,000-node cloud environment with up to 30% malicious traffic demonstrate that the hybrid ECC-quantum model achieves significant improvements in resistance to volumetric, protocol-based, and application-layer DDoS attacks, while maintaining low latency and high throughput suitable for production cloud deployments. All reported performance figures are simulation-based rather than obtained from a physical deployment. HEQCSF provides quantum-resistant key establishment and confidentiality through CRYSTALS-Kyber, whereas client authentication continues to rely on classical elliptic-curve digital signature algorithm (ECDSA) and is therefore not yet fully quantum-resistant; hybrid ECDSA+Dilithium co-signatures for fully quantum-resistant authentication are identified as future work.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controlled quantum teleportation of a four-qubit cluster state using a seven-qubit entangled state in a noisy environment","authors":"Sifan Feng,&nbsp;Yuqi Wang,&nbsp;Jiahao Wu,&nbsp;Jianling Chen,&nbsp;Jiafa Zheng,&nbsp;Hong Zhao","doi":"10.1007/s11128-026-05354-3","DOIUrl":"10.1007/s11128-026-05354-3","url":null,"abstract":"<div><p>In this work, an efficient controlled quantum teleportation scheme was developed for the transmission of a four-qubit cluster state. The proposed approach relied on a seven-qubit entangled state as the quantum channel, enabling deterministic reconstruction of the quantum state through three-qubit and single-qubit projective measurements followed by corresponding unitary operations. Beyond the ideal scenario, the scheme’s robustness was evaluated by quantifying fidelity dynamics under bit-flip, phase-damping, and amplitude-damping decoherence channels, revealing a pronounced asymmetry: the protocol is highly vulnerable to bit-flip errors (<span>(f=0.4856)</span> at <span>(p=0.1)</span>), exhibits strong robustness against phase-damping noise (<span>(f=0.7824)</span>), and shows intermediate, state-dependent behavior under amplitude-damping noise (<span>(f=0.7053)</span> for balanced amplitudes). Compared with existing multi-party teleportation frameworks, the present scheme offers a more resource-efficient architecture with enhanced intrinsic operational efficiency. The proposed approach offers an effective solution for supervised information transfer in noisy quantum networking systems.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"25 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}