Wenyuan Xiao, Wenqiong Zhang, Longhui Shen, Jia Bao, Bin Guo
{"title":"Global quantum discord in an Ising model with transverse and longitudinal magnetic fields","authors":"Wenyuan Xiao, Wenqiong Zhang, Longhui Shen, Jia Bao, Bin Guo","doi":"10.1007/s11128-024-04567-8","DOIUrl":"10.1007/s11128-024-04567-8","url":null,"abstract":"<div><p>Global quantum discord (GQD) refers to the number of quantum correlations present in the entire quantum many-body system, rather than just between two subsystems. Here, we utilize GQD to characterize quantum phase transitions in an Ising chain subjected to both transverse and longitudinal magnetic fields. We investigate the effects of the transverse magnetic field <span>(h_{x})</span>, longitudinal magnetic field <span>(h_{z})</span>, and temperature <i>T</i> on the properties of GQD while keeping the coupling strength <i>J</i> between spins constant. We show that we can perfectly illustrate the critical points of the model by analyzing the singularity of GQD. We find that the GQD exhibits an increase as the system size <i>N</i> increases, regardless of whether the temperature is zero or finite. We present the phase diagram of a mixed Ising model under the combined influence of <span>(h_{x})</span> and <span>(h_{z})</span>. Moreover, we show that we can use the features of GQD at lower temperatures to identify QPTs in quantum many-body systems and determine their critical points, as achieving absolute zero temperatures is practically impossible. Additionally, we show that GQD both at zero and finite temperatures show a linear behavior of the system size <i>N</i>, i.e., <span>(mathcal {G}=kN+b)</span>, in which <i>k</i> and <i>b</i> are the fitting parameters.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434755","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 convolution and neighborhood pixel extraction scheme based on NEQR","authors":"Shuo Cai, Ri-Gui Zhou","doi":"10.1007/s11128-024-04562-z","DOIUrl":"10.1007/s11128-024-04562-z","url":null,"abstract":"<div><p>At the vanguard of quantum computation and quantum machine learning, the role of convolutional operations is pivotal, serving as the linchpin of image processing techniques. Currently, various quantum convolutional circuits have been proposed, but they are all based on non-ground state encoding. Quantum convolution methods based on ground state encoding, particularly NEQR, have not yet been studied. To address the aforementioned issues, a novel quantum convolutional circuit has been designed based on arithmetic operation modules and quantum amplitude estimation modules. This circuit performs convolution operations on NEQR encoded quantum images. Furthermore, considering the limitations of existing neighborhood pixel extraction methods in quantum image processing, this quantum convolutional circuit has been utilized to design a quantum neighborhood pixel extraction circuit. Neighborhood pixels from a specified pixel in NEQR encoded quantum images are accurately extracted by this circuit, providing a novel solution. Through comparative analysis, our research results show certain advantages in time and space complexity over existing technologies.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431032","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}
J. C. S. Rocha, R. F. I. Gomes, W. A. T. Nogueira, R. A. Dias
{"title":"Estimating the number of states of a quantum system via the rodeo algorithm for quantum computation","authors":"J. C. S. Rocha, R. F. I. Gomes, W. A. T. Nogueira, R. A. Dias","doi":"10.1007/s11128-024-04552-1","DOIUrl":"10.1007/s11128-024-04552-1","url":null,"abstract":"<div><p>In the realm of statistical physics, the number of states in which a system can be realized with a given energy is a key concept that bridges the microscopic and macroscopic descriptions of physical systems. For quantum systems, many approaches rely on the solution of the Schrödinger equation. In this work, we demonstrate how the recently developed rodeo algorithm can be utilized to determine the number of states associated with all energy levels without any prior knowledge of the eigenstates. Quantum computers, with their innate ability to address the intricacies of quantum systems, make this approach particularly promising for the study of the thermodynamics of those systems. To illustrate the procedure’s effectiveness, we apply it to compute the number of states of the 1D transverse field Ising model and, consequently, its specific heat, proving the reliability of the method presented here.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431033","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":"Effects of chromatic dispersion on single-photon temporal wave functions in quantum communications","authors":"Artur Czerwinski, Xiangji Cai, Saeed Haddadi","doi":"10.1007/s11128-024-04551-2","DOIUrl":"10.1007/s11128-024-04551-2","url":null,"abstract":"<div><p>In this study, we investigate the effects of chromatic dispersion on single-photon temporal wave functions (TWFs) in the context of quantum communications. Departing from classical beam analysis, we focus on the temporal shape of single photons, specifically exploring generalized Gaussian modes. From this foundation, we introduce chirped and unchirped Gaussian TWFs, demonstrating the impact of the chirp parameter in mitigating chromatic dispersion effects. Furthermore, we extend our investigation to time-bin qubits, a topic of ongoing research relevance. By exploring the interplay of dispersion effects on qubit interference patterns, we contribute essential insights to quantum information processing. This comprehensive analysis considers various parameters, introducing a level of complexity not previously explored in the context of dispersion management. We demonstrate the relationships between different quantities and their impact on the spreading of TWFs. Our results not only deepen the theoretical understanding of single-photon TWFs but also offer practical guidelines for system designers to optimize symbol rates in quantum communications.\u0000</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11128-024-04551-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410977","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. Mehrabankar, P. Mahmoudi, F. Abbasnezhad, D. Afshar, A. Isar
{"title":"Effect of noisy environment on secure quantum teleportation of unimodal Gaussian states","authors":"S. Mehrabankar, P. Mahmoudi, F. Abbasnezhad, D. Afshar, A. Isar","doi":"10.1007/s11128-024-04545-0","DOIUrl":"10.1007/s11128-024-04545-0","url":null,"abstract":"<div><p>Quantum networks rely on quantum teleportation, a process where an unknown quantum state is transmitted between sender and receiver via entangled states and classical communication. In our study, we utilize a continuous variable two-mode squeezed vacuum state as the primary resource for quantum teleportation, shared by Alice and Bob, while exposed to a squeezed thermal environment. Secure quantum teleportation necessitates a teleportation fidelity exceeding 2/3 and the establishment of two-way steering of the resource state. We investigate the temporal evolution of steering and teleportation fidelity to determine critical parameter values for secure quantum teleportation of a coherent Gaussian state. Our findings reveal constraints imposed by temperature, dissipation rate, and squeezing parameters of the squeezed thermal reservoir on the duration of secure quantum teleportation. Intriguingly, we demonstrate that increasing the squeezing parameter of the initial state effectively extends the temporal window for a successful secure quantum teleportation.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11128-024-04545-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410974","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}
Matteo Vandelli, Alessandra Lignarolo, Carlo Cavazzoni, Daniele Dragoni
{"title":"Evaluating the practicality of quantum optimization algorithms for prototypical industrial applications","authors":"Matteo Vandelli, Alessandra Lignarolo, Carlo Cavazzoni, Daniele Dragoni","doi":"10.1007/s11128-024-04560-1","DOIUrl":"10.1007/s11128-024-04560-1","url":null,"abstract":"<div><p>The optimization of the power consumption of antenna networks is a problem with a potential impact in the field of telecommunications. In this work, we investigate the application of the quantum approximate optimization algorithm (QAOA) and the quantum adiabatic algorithm (QAA), to the solution of a prototypical model in this field. We use state vector emulation in a high-performance computing environment to compare the performance of these two algorithms in terms of solution quality, using selected evaluation metrics. We estimate the circuit depth scaling with the problem size while maintaining a certain level of solution quality, and we extend our analysis up to 31 qubits, which is rarely addressed in the literature. Our calculations show that as the problem size increases, the probability of measuring the exact solution decreases exponentially for both algorithms. This issue is particularly severe when we include constraints in the problem, resulting in full connectivity between the sites. Nonetheless, we observe that the cumulative probability of measuring solutions close to the optimal one remains high also for the largest instances considered in this work. Our findings keep the way open to the application of these algorithms, or variants thereof, to generate suboptimal solutions at scales relevant to industrial use cases.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142411011","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}
Eduardo Barreto Brito, Fernando M. de Paula Neto, Nadja Kolb Bernardes
{"title":"Quantum classifier based on open quantum systems with amplitude information loading","authors":"Eduardo Barreto Brito, Fernando M. de Paula Neto, Nadja Kolb Bernardes","doi":"10.1007/s11128-024-04526-3","DOIUrl":"10.1007/s11128-024-04526-3","url":null,"abstract":"<div><p>Although the studies on quantum algorithms have been progressing, it is still necessary to broaden the investigation of open quantum systems. In this study, we present the use of an open quantum system to implement a quantum classifier algorithm. Zhang et al. propose a one-QuBit system interacting with the environment through a unitary operator from the Hamiltonian. In our proposal, the input data are loaded into the amplitude of the environment instead of being in the unitary operator. This change positively impacts the performance of different databases tested and causes a difference in the system entanglement behavior. For evaluation, the Zhang et al. proposed models were tested in four real-world datasets and seven other toy problems. The results are evaluated according to accuracy and F1 score. A deeper analysis of the Iris dataset is also done, checking the creation of entanglement and an extensive random search for better parameters on the proposed model. The results show that for most real-world dataset configurations, the proposed model, although having a simpler decision area, performed better than the one inspired by the Zhang et al. model, and that there is no pattern for the system entanglement in the Iris dataset.\u0000</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410663","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":"No-interfering quantum key distribution","authors":"Yang Yu, Wei Li, Le Wang, Shengmei Zhao","doi":"10.1007/s11128-024-04546-z","DOIUrl":"10.1007/s11128-024-04546-z","url":null,"abstract":"<div><p>The well-known twin-field quantum key distribution (TF-QKD) protocol is the first one to overcome the fundamental rate-distance limit without quantum repeaters. It encodes the key information into phases of the light, and has a secret key rate scaling with the square root of the transmission transmittance by taking advantage of single-photon interference. Inspired by the idea in TF-QKD, we proposed a polarization encoding protocol to break the rate-distance limit by the property of the two states with orthogonal polarizations, named no-interfering QKD (NI-QKD). Two effective events are defined in which no interference happens. Simulation results show that the proposed protocol also holds the capacity of surpassing the Pirandola–Laurenza–Ottaviani–Banchi (PLOB) bound. Moreover, it has a better performance than no-phase-postselection TF-QKD (NPP-TF-QKD), one of TF-QKD’s variants, and its communication distance can reach at most 424 km. The relationships between the performance and the polarization misalignment, the phase mismatch are discussed. It turns out that one event is very robust against polarization misalignment while the other is not, and both events are sensitive to phase mismatch. The mutual information of the effective events under collective attack is also calculated, which is lower than that of NPP-TF-QKD. This new protocol provides a new angle of exploring QKD and improving the secret rate.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410747","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}
Srushti Patil, Shreya Banerjee, Prasanta K. Panigrahi
{"title":"NISQ-friendly measurement-based quantum clustering algorithms","authors":"Srushti Patil, Shreya Banerjee, Prasanta K. Panigrahi","doi":"10.1007/s11128-024-04553-0","DOIUrl":"10.1007/s11128-024-04553-0","url":null,"abstract":"<div><p>Two novel measurement-based, quantum clustering algorithms are proposed based on quantum parallelism and entanglement. The first algorithm follows a divisive approach. The second algorithm is based on unsharp measurements, where we construct an effect operator with a Gaussian probability distribution to cluster similar data points. A major advantage of both algorithms is that they are simplistic in nature, easy to implement, and well suited for noisy intermediate scale quantum computers. We have successfully applied the first algorithm on a concentric circle data set, where the classical clustering approach fails, as well as on the Churritz data set of 130 cities, where we show that the algorithm succeeds with very low quantum resources. We applied the second algorithm on the labeled Wisconsin breast cancer dataset, and found that it is able to classify the dataset with high accuracy using only <i>O</i>(<i>log</i>(<i>D</i>)) qubits and polynomial measurements, where <i>D</i> is the maximal distance within any two points in the dataset. We also show that this algorithm works better with an assumed measurement error in the quantum system, making it extremely well suited for NISQ devices.\u0000</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410753","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":"(n, m, p)-type quantum network configuration and its nonlocality","authors":"Zan-Jia Li, Ying-Qiu He, Dong Ding, Ming-Xing Yu, Ting Gao, Feng-Li Yan","doi":"10.1007/s11128-024-04541-4","DOIUrl":"10.1007/s11128-024-04541-4","url":null,"abstract":"<div><p>A quantum network that shares entangled sources among distant nodes enables us to distribute entanglement along the network by suitable measurements. Network nonlocality means that it does not admit a network model involving local variables emitted from independent sources. In this work, we construct an (<i>n</i>, <i>m</i>, <i>p</i>)-type quantum network configuration and then derive the corresponding <i>n</i>-local correlation inequalities based on the assumption of independent sources. As a more general quantum network configuration, it can cover most of the existing network models, such as the typical chain network, star network and ring network, and provides both centerless and asymmetric network topologies, involving cyclic and acyclic configurations. We demonstrate the non-<i>n</i>-locality of the present network by calculating the violation of the <i>n</i>-local inequality with bipartite entangled sources and Pauli measurements. This allows us to simplify the analysis of various network configurations using a general network parameterized by <i>n</i>, <i>m</i> and <i>p</i>.</p></div>","PeriodicalId":746,"journal":{"name":"Quantum Information Processing","volume":"23 10","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410737","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}