{"title":"Satellite-based multi-user quantum conference key agreement","authors":"Haoyang Wang, Qiang Zeng, Haiqiang Ma","doi":"10.1007/s11128-025-04956-7","DOIUrl":"10.1007/s11128-025-04956-7","url":null,"abstract":"<div><p>Quantum communication is evolving as the next generation of secret sharing technology. Compared to the rapid development in bipartite quantum communications, multipartite quantum network still awaits significant improvements in transmission distances, covering areas, and number of users. Current fiber-based quantum networks are challenged by preparing multi-particle entangled states and the high loss of fiber links. Inspired by the source-independent quantum conference key agreement based on Bell states and the satellite-to-ground transmission links, we proposed two satellite-based quantum network architectures, including up-links and down-links. The simulated key rates are maintained when the number of users increases for both two proposed architectures. The down-link architecture ensures a secure key rate exceeding <span>(10^{-7})</span> bit/pulse even over a distance of 1000 km. Our work offers viable solutions and quantitative references toward realizing scalable satellite-based secure quantum communication networks.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256217","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":"A quantum circuit parameterized decomposition method based on local synthesis","authors":"Yu Zhang, Xueyun Cheng, Fei Ding, Pengcheng Zhu, Zhijin Guan, Hui Gu","doi":"10.1007/s11128-025-04941-0","DOIUrl":"10.1007/s11128-025-04941-0","url":null,"abstract":"<div><p>To reduce the number of basis gates after quantum circuit decomposition, enhance overall fidelity, and improve the expressivity of complex quantum programs, this paper proposes a quantum circuit parameterized decomposition method based on local synthesis (PDBLS). Prior to decomposition, local synthesis is applied to analyze and optimize the circuit structure by formally defining and automatically collecting “compressible blocks”, while also generating new compressible blocks through gate-exchange reordering, thereby reducing the number of basis gates requiring decomposition. At the theoretical level, within the Weyl chamber framework, we provide a rigorous proof showing that the optimal number of basis gates required for decomposing a two-qubit gate (2Q) corresponds exactly to the coverage layer in which its Weyl chamber coordinate lies. In the decomposition stage, we introduce a parameterized decomposition template alternating basis gates with U3 gates, combined with a cost function defined by decomposition fidelity and hardware fidelity, as well as a layer-by-layer deepening strategy with L-BFGS optimization, ensuring minimum basis gate usage while maintaining target fidelity. Experimental results demonstrate that PDBLS significantly reduces the number of 2Q basis gates across various benchmark circuits and gate sets, showing advantages under both exact and approximate decomposition conditions, and exhibiting strong scalability on large-scale circuits.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256214","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}
Federico Holik, Marcelo Losada, Giannina Zerr, Lorena Rebón, Diego Tielas
{"title":"Group-invariant estimation of symmetric states generated by noisy quantum computers","authors":"Federico Holik, Marcelo Losada, Giannina Zerr, Lorena Rebón, Diego Tielas","doi":"10.1007/s11128-025-04944-x","DOIUrl":"10.1007/s11128-025-04944-x","url":null,"abstract":"<div><p>The problem of quantum state estimation is crucial in the development of quantum technologies. In particular, the use of symmetric quantum states is useful in many relevant applications. In this work, we analyze the task of reconstructing the density matrices of symmetric quantum states generated by a quantum processor. For this purpose, we take advantage of an estimation technique that results to be equivalent to the quantum maximum entropy (MaxEnt) estimation, and which was recently adapted to quantum states with arbitrary symmetries. The smart use of prior knowledge of the quantum state symmetries allows for a reduction in both, the number of measurements that need to be made on the system, and the size of the computational problem to store and process the data, resulting in a better overall performance of the estimator as well. After performing numerical simulations, we implement some examples of symmetric states in IonQ quantum processors, and estimate them using the proposed technique. The results are in good agreement with numerical simulations, showing that the proposed method is a good estimator that allows to save both, experimental and computational resources. \u0000</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256216","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":"Dynamic evolution of quantum entanglement with quantum Lyapunov control in a two-qubit Heisenberg XXZ model under the effect of DM and KSEA interactions","authors":"Song Jon, Kang Unil, Jyongyon Kim, Chongil Kim","doi":"10.1007/s11128-025-04950-z","DOIUrl":"10.1007/s11128-025-04950-z","url":null,"abstract":"<div><p>In this paper, we investigate the dynamic evolution of quantum correlation using the quantum Lyapunov control in the two-qubit Heisenberg XXZ model under the effect of DM and KSEA interaction. When both the DM and KSEA interactions in the x-, y- and z-direction are taken into account, quantum correlations such as concurrence exhibit the sudden death and birth and lead to chaotic behavior during evolution. To solve this problem, we apply a time-varying field, not a constant field into the x- and z-direction. In other words, the quantum Lyapunov control is used at each time to determine the strength of the magnetic field in order to increase the quantum correlation. Numerical simulation result shows that the method proposed in this paper does not generate sudden death and birth of quantum correlations during evolution, and that even after a certain time if the magnetic field is removed, quantum correlations remain unchanged and to be a certain value. This result provides the possibility to use spin chains as quantum channels to perform quantum information processing.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256215","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":"Convolutional and computer vision methods for accelerating partial tracing operation in quantum mechanics for general qudit systems","authors":"Aaditya Rudra, M. S. Ramkarthik","doi":"10.1007/s11128-025-04938-9","DOIUrl":"10.1007/s11128-025-04938-9","url":null,"abstract":"<div><p>Partial trace is a mathematical operation used extensively in quantum mechanics to study the subsystems of a composite quantum system and in several other applications such as calculation of entanglement measures. Calculating partial trace proves to be a computational challenge with an increase in the number of qubits as the Hilbert space dimension scales up exponentially and more so as we go from two-level systems (qubits) to <i>D</i>-level systems. In this paper, we present a novel approach to the partial trace operation that provides a geometrical insight into the structures and features of the partial trace operation. We utilize these facts to propose a new method to calculate partial trace using signal processing concepts, namely convolution, filters and multigrids. Our proposed method of partial tracing significantly reduces the computational complexity by directly selecting the features of the reduced subsystem rather than eliminating the traced-out subsystems. We give a detailed description of our method and provide some explicit examples of the computation. Our method can be generalized further to a <i>D</i>-level system of <i>N</i>-particles with a considerable reduction in computation time. The arithmetic complexity of our algorithm is <span>(mathcal {O}left( D^{2N - n}right) )</span> with <i>n</i> subsystems partially traced out. We also observe various geometrical patterns and self-forming fractal structures, which we discuss here. We give numerical evidence to all the claims.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256091","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":"An efficient quantum secret sharing scheme for general access structure based on a novel partitioning technique","authors":"Suchandan Ghosh, Avishek Adhikari","doi":"10.1007/s11128-025-04949-6","DOIUrl":"10.1007/s11128-025-04949-6","url":null,"abstract":"<div><p>Secret sharing is a fundamental cryptographic technique that distributes confidential information into multiple shares, ensuring that only authorized subsets of participants can reconstruct the original secret. In this paper, we propose a novel qubit-based approach to the Quantum General Secret Sharing Scheme, enhancing security for general access structures. Our framework efficiently supports all monotone access structures by representing the collection of minimal qualified sets, offering a flexible and scalable quantum solution. We introduce an innovative partitioning method for the minimal qualified sets, ensuring quantum-compatible share generation. The scheme employs a structured quantum encoding mechanism to generate quantum shares, or shadow qubits, providing robust security against unauthorized access. Using linear algebra and quantum information-theoretic techniques, we rigorously prove that unauthorized participants gain no information about the secret. Additionally, we design an efficient quantum reconstruction algorithm that enables authorized participants to recover the secret from their distributed shadow qubits. Unlike previous works, our approach avoids the use of quantum Fourier transform (QFT), which, while powerful, leads to deeper circuits and high gate complexity that are impractical for NISQ devices. By relying solely on CNOT and Hadamard gates, our construction enables low-depth, hardware-friendly circuits suitable for implementation. The circuit complexity is linear in the number of participants, offering better scalability than previous quantum constructions for general access structures. By using qubits instead of qudits, we reduce noise and improve performance. Furthermore, by incorporating entanglement for enhanced security, our scheme eliminates the need for secure communication channels, requiring only a classically authenticated quantum channel. We have also implemented this in Python using <span>Criq</span>, which verifies our protocol.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256200","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":"Correction: Deterministic generation of hybrid entangled states using quantum walks","authors":"Jaskaran Singh, Vikash Mittal, Soumyakanti Bose","doi":"10.1007/s11128-025-04935-y","DOIUrl":"10.1007/s11128-025-04935-y","url":null,"abstract":"","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210175","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":"Discrete-time quantum walk search on the cycle graph with weighted self-loop","authors":"Yong Qing Tiong, Kai Lin Ong, Ian K. T. Tan","doi":"10.1007/s11128-025-04945-w","DOIUrl":"10.1007/s11128-025-04945-w","url":null,"abstract":"<div><p>The evolution operator of the lackadaisical quantum walk on a weighted cycle graph with self-loop weight <span>(w>0)</span> is examined. With Grover oracle, the effect of different values of <span>(w)</span> on the success probability of the search under various hyperparameter combinations is analyzed. The success probability function of the first few steps is provided algebraically, which in turn highlights the role of <span>(w)</span> in governing the evolutionary behavior of the quantum walk search. These studies subsequently allow the numerical results to be obtained for various hyperparameter combinations, showing that the highest success probability for the weighted cycle graph with <span>(N)</span> vertices is achieved using a flip-flop shift operator, a weighted coin superposition initial state, and <span>(w=frac{1.26}{N})</span>. A comparison is also made with other known oracle, demonstrating that the proposed configuration provides a better trade-off between success probability and runtime. An extension of the study to the SKW scheme is also included, and it demonstrates that the scheme provides more variability and potential for quantum walk search.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11128-025-04945-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210359","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}
S. J. Chen, D. C. Qian, Y. H. Sun, M. K. Wu, W. W. Cheng
{"title":"Frequency modulation-controlled Einstein–Podolsky–Rosen steering in leaky cavities","authors":"S. J. Chen, D. C. Qian, Y. H. Sun, M. K. Wu, W. W. Cheng","doi":"10.1007/s11128-025-04946-9","DOIUrl":"10.1007/s11128-025-04946-9","url":null,"abstract":"<div><p>Numerous strategies have been proposed to manipulate and protect symmetric quantum correlations from decoherence. However, there needs to be more emphasis on asymmetric ones, such as Einstein–Podolsky–Rosen (EPR) steering. In this study, we delve into EPR steering between two frequency-modulated qubits coupled to a zero-temperature reservoir individually, in both weak and strong coupling regimes. We consider a scenario where each qubit is locally identically coupled to its environment. The results demonstrate that the decay of EPR steering between the two qubits can be delayed remarkably by controlling frequency modulation parameters, regardless of whether the system exhibits Markovian or non-Markovian behavior. Moreover, we observe that a precise balance between modulation strength <span>(delta )</span> and frequency <span>(varOmega )</span>, determining the zeros of the Bessel function <span>(J_{0}(delta /varOmega ))</span>, can significantly enhance EPR steering in the strong coupling regime. Furthermore, we investigate the asymmetric nature of EPR steering by examining a scenario where one of the qubits remains unmodulated. We thoroughly analyze the impact of modulation parameters on the occurrence of EPR steering sudden death. The findings highlight that asymmetry properties, such as one-way and two-way steering, can be effectively manipulated by adjusting the frequency modulation parameters, even when the initial two-qubit state is symmetrical. These results suggest that it is feasible to safeguard EPR steering and control its asymmetry properties without requiring additional quantum resources.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210883","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}
Christoph Brockt-Haßauer, Vyacheslav Shatokhin, Aishvarya Kumar Jain, Corinna Köpke, Alexander Stolz, Mirjam Fehling-Kaschek, Andreas Buchleitner
{"title":"Exploring the use of quantum computers for resilience analysis in critical infrastructure networks","authors":"Christoph Brockt-Haßauer, Vyacheslav Shatokhin, Aishvarya Kumar Jain, Corinna Köpke, Alexander Stolz, Mirjam Fehling-Kaschek, Andreas Buchleitner","doi":"10.1007/s11128-025-04947-8","DOIUrl":"10.1007/s11128-025-04947-8","url":null,"abstract":"<div><p>Resilience analysis of networks representing critical infrastructure is a computationally hard problem, and the question arises of whether quantum computers may be beneficial for this purpose. On the way towards an answer to this problem, we map a small critical infrastructure network on a quantum network composed of dipole–dipole-coupled nodes. The latter are each equipped with up to three discrete (quantum) states, two of which support the connectivity of the network, while the third state, reachable through nondeterministic spontaneous processes, represents a ‘broken’ node. A finite ‘repair’ time is needed to restore the node. To study the dynamics of such networks on a quantum computer, we derive unitary dilations of Kraus operators governing the evolution of our open quantum network, and generate corresponding quantum circuits using the <span>qiskit</span> interface. We then study the population dynamics of several cases of increasing complexity on the quantum hardware. We discuss how scaling of errors is related to the depth of the quantum circuits. Ultimately, we show that open quantum systems can be used for modelling critical infrastructure, but quantum computers with much lower error rates than currently available are required for a quantitative resilience analysis.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"24 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11128-025-04947-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210360","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}