Advanced quantum technologies最新文献

{"title":"Learning the Expressibility of Quantum Circuit Ansatz Using Transformer","authors":"Fei Zhang,&nbsp;Jie Li,&nbsp;Zhimin He,&nbsp;Haozhen Situ","doi":"10.1002/qute.202400366","DOIUrl":"10.1002/qute.202400366","url":null,"abstract":"<p>With the exponentially faster computation for certain problems, quantum computing has garnered significant attention in recent years. Variational quantum algorithms are crucial methods to implement quantum computing, and an appropriate task-specific quantum circuit ansatz can effectively enhance the quantum advantage of VQAs. However, the vast search space makes it challenging to find the optimal task-specific ansatz. Expressibility, quantifying the diversity of quantum circuit ansatz states to explore the Hilbert space effectively, can be used to evaluate whether one ansatz is superior to another. In this work, using a transformer model to predict the expressibility of quantum circuit ansatze is proposed. A dataset containing random PQCs generated by the gatewise pipeline, with varying numbers of qubits and gates is constructed. The expressibility of the circuits is calculated using three measures: KL divergence, relative KL divergence, and maximum mean discrepancy. A transformer model is trained on the dataset to capture the intricate relationships between circuit characteristics and expressibility. Four evaluation metrics are employed to assess the performance of the transformer. Numerical results demonstrate that the trained model achieves high performance and robustness across various expressibility measures. This research can enhance the understanding of the expressibility of quantum circuit ansatze and advance quantum architecture search algorithms.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144273275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Light-Cone Feature Selection for Quantum Machine Learning","authors":"Yudai Suzuki,&nbsp;Rei Sakuma,&nbsp;Hideaki Kawaguchi","doi":"10.1002/qute.202400647","DOIUrl":"10.1002/qute.202400647","url":null,"abstract":"<p>Feature selection plays an essential role in improving the predictive performance and interpretability of trained models in classical machine learning. On the other hand, the usability of conventional feature selection can be limited for quantum machine learning (QML) tasks; the technique may not provide a clear interpretation on embedding quantum circuits for classical data tasks and, more importantly, is not applicable to quantum data tasks. In this work, a feature selection method is proposed with a specific focus on QML. This scheme treats the light-cones (i.e., subspace) of quantum models as features and then select relevant ones through training of the corresponding local quantum kernels. Its versatility is numerically demonstrated for four different applications using toy tasks: (1) feature selection of classical inputs, (2) circuit architecture search for data embedding, (3) compression of quantum machine learning models and (4) subspace selection for quantum data. The proposed framework paves the way toward applications of QML to practical tasks. Also, this technique could be used to practically test if the QML tasks really need quantumness, while it is beyond the scope of this work.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144273273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terahertz Continuous-Variable Measurement-Device-Independent Quantum key Distribution with Photon Subtraction in Inter-Satellite Links Communication","authors":"Chengji Liu,&nbsp;Zhe Xu,&nbsp;Xinyu Wan,&nbsp;Mengyao Hou,&nbsp;Lu Wang,&nbsp;Qingshan Li","doi":"10.1002/qute.202400570","DOIUrl":"10.1002/qute.202400570","url":null,"abstract":"<p>Quantum communication in the terahertz (THz) band is an important technology for next-generation high-capacity wireless networks, and inter-satellite quantum key distribution in low-earth-orbit (LEO) is one of the critical research directions. A terahertz continuous-variable measurement-device-independent quantum key distribution (CV-MDI-QKD) with photon subtraction for secure inter-satellite link communications, derive the security bounds for the protocol, is proposed and the performance of the inter-satellite link in the asymptotic limit, in addition to obtaining a tighter protocol bound by considering finite size effects, is evaluated. Through simulation calculations, the method can maintain high secret key rates and robust security, which will provide a more effective way to build future quantum networks.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 6","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144273518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient Simulation of Open Quantum Systems on NISQ Trapped-Ion Hardware","authors":"Colin Burdine,&nbsp;Nora Bauer,&nbsp;George Siopsis,&nbsp;Enrique P. Blair","doi":"10.1002/qute.202400606","DOIUrl":"10.1002/qute.202400606","url":null,"abstract":"<p>Simulating open quantum systems, which interact with external environments, presents significant challenges on noisy intermediate-scale quantum (NISQ) devices due to limited qubit resources and noise. In this study, an efficient framework is proposed for simulating open quantum systems on NISQ hardware by leveraging a time-perturbative Kraus operator representation of the system's dynamics. This approach avoids the computationally expensive Trotterization method and exploits the Lindblad master equation to represent time evolution in a compact form, particularly for systems satisfying specific commutation relations. The efficiency of this method is demonstrated by simulating quantum channels, such as the continuous-time Pauli channel and damped harmonic oscillators, on NISQ trapped-ion hardware, including IonQ Harmony and Quantinuum H1-1. Additionally, hardware-agnostic error mitigation techniques are introduced, including Pauli channel fitting and quantum depolarizing channel inversion, to enhance the fidelity of quantum simulations. These results show strong agreement between the simulations on real quantum hardware and exact solutions, highlighting the potential of Kraus-based methods for scalable and accurate simulation of open quantum systems on NISQ devices. This framework opens pathways for simulating more complex systems under realistic conditions in the near term.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 9","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/qute.202400606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation of High-Fidelity Entangled Cat States with Composite Pulses","authors":"Ge-Ge Gu,&nbsp;Dong-Sheng Li,&nbsp;Ye-Hong Chen,&nbsp;Bi-Hua Huang,&nbsp;Yan Xia","doi":"10.1002/qute.202400518","DOIUrl":"10.1002/qute.202400518","url":null,"abstract":"<p>A protocol is proposed for the preparation of high-fidelity entangled cat states with composite pulses. The physical model contains two Kerr-nonlinear resonators and a cavity. By properly designing the parameters, each Kerr-nonlinear resonator is confined in the cat-state subspace and the entangled cat states can be generated efficiently. Composite two-photon drives are introduced with multiple amplitudes and frequencies to improve the fidelity of the entangled cat states in the presence of parameter errors. The performance of the protocol is estimated by taking into account the parametric errors and decoherence. Numerical simulation results show that, the protocol is robustness to timing error, detuning error, and decoherence. It is hoped that the protocol may provide a method for preparing stable entangled cat states.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 8","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144833304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation and Manipulation of One-Way Steering in Optomagnomechanical System","authors":"Jinke Cao,&nbsp;Mei-Rong Wei,&nbsp;Qi Guo,&nbsp;Huatang Tan,&nbsp;Gang Li,&nbsp;Tiancai Zhang","doi":"10.1002/qute.202400547","DOIUrl":"10.1002/qute.202400547","url":null,"abstract":"<p>It is showed how to generate and control the one-way optomechanical steering in an optomagnomechanical system. In the scheme, the magnetostriction-induced deformation displacement of a ferrimagnet couples to an optical cavity by radiation-pressure interaction. The optical cavity resonates with the Stokes sideband of the laser drive field, leading to the optomechanical parametric down-conversion interaction. The magnon mode resonates with the anti-Stokes sideband of the microwave drive field, thereby cooling the mechanical motion. By adjusting the detuning between the magnon mode and the microwave drive field, we show the relative steady-state population numbers of photons and phonons will be changed, therefore, the direction of the optomechanical steering can be controlled. The control of the quantum steering in this scheme does not require the introduction of additional dissipation and damping of the entangled parties, which means the one-way steering can be generated with low mechanical damping, and has strong robustness against thermal noise. This finding may provide a novel platform to generate and control quantum steering in hybrid quantum system.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 8","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144833306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Gradient Field Compensation in Multi-Channel Atomic Magnetometers with Adaptive Algorithms","authors":"Yaohua Zhang,&nbsp;Zhuo Wang,&nbsp;Li Cao,&nbsp;Junjian Tang,&nbsp;Yueyang Zhai,&nbsp;Yaxiang Wang","doi":"10.1002/qute.202400346","DOIUrl":"10.1002/qute.202400346","url":null,"abstract":"<p>The utilization of spin-exchange relaxation-free (SERF) effects in atomic magnetometers is demonstrated significant potential for ultrasensitive biomagnetic field measurements. However, the presence of residual gradient fields could introduce additional spin-exchange relaxation, which will attenuate the response of the magnetometer. Consequently, it is crucial to compensate these residual gradients for maintaining high sensitivity and accuracy in SERF magnetometers. This study developed an optimized technique that leveraged both gradient and homogeneous coils to rapidly mitigate position-dependent gradients. By applying adaptive moment estimation (Adam) optimization, the quadratic loss function is efficiently solved and the optimal current is determined. This experiment demonstrated over 90% suppression of the residual fields and a significant reduction in the inter-channel deviations by an order of magnitude. In a simulated large gradient field environment, the sensitivities of multi-channel magnetometers improved from 100 to 15 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>fT</mi>\u0000 <mo>/</mo>\u0000 <msup>\u0000 <mi>Hz</mi>\u0000 <mrow>\u0000 <mn>1</mn>\u0000 <mo>/</mo>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$mathrm{fT/Hz^{1/2}}$</annotation>\u0000 </semantics></math> after compensation. The proposed method showcased substantial enhancements in residual homogeneity and sensor sensitivity, underscoring its efficiency. Compared with nested coil approaches, the coordinated use of gradient and homogeneous coils, along with Adam optimization, offered a robust, efficient, and rapid solution for gradient compensation. The proposed method effectively mitigated the adverse effects of residual fields and enhanced the performance of multi-channel SERF magnetometers. Importantly, this approach represents a more practical solution for gradient field compensation within a single cell, particularly for future commercial applications of array SERF magnetometers.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 7","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topological Phases and Anomalous Phase Transitions in Topolectrical Circuit","authors":"Kai-Xin Hu,&nbsp;Zhi-Xu Zhang,&nbsp;Yu Yan,&nbsp;Shutian Liu,&nbsp;Wen-Xue Cui,&nbsp;Ji Cao,&nbsp;Shou Zhang,&nbsp;Hong-Fu Wang","doi":"10.1002/qute.202400649","DOIUrl":"10.1002/qute.202400649","url":null,"abstract":"<p>Distinct topological phases and anomalous phase transitions are investigated in a 2D topolectrical circuit system. The topological phases of the system are characterized by the Chern number and fractional wave polarization, and the phase-transition lines (PTLs) obtained from the phase diagrams are consistent with those derived from the zero-energy condition. It is shown that different PTLs emerge gapless points at different high-symmetry points of the first Brillouin zone. Moreover, gapless points appear simultaneously at two different high-symmetry points when two PTLs intersect. In topological phases with a nonzero Chern number, the chiral edge states are present when periodic boundary conditions (PBCs) are applied along any one direction. In topological phases with a nonzero fractional wave polarization, there are in-gap edge states when PBCs are applied along one direction and near-bulk edge states along another direction. The edge states are present at the anomalous PTLs between two nontrivial phases and are absent at the normal PTLs between the trivial and nontrivial phases. Furthermore, an efficient method is proposed to identify desirable topological edge states based on the impedance of the topolectrical circuit system. The work reveals that the presence of anomalous phase transitions is crucial for understanding the essentials of topological phase transitions.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 9","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Verification of Entangled States Under Noisy Measurements","authors":"Lan Zhang,&nbsp;Yinfei Li,&nbsp;Ye-Chao Liu,&nbsp;Jiangwei Shang","doi":"10.1002/qute.202400575","DOIUrl":"10.1002/qute.202400575","url":null,"abstract":"<p>Entanglement plays an indispensable role in numerous quantum information and quantum computation tasks, underscoring the need for efficiently verifying entangled states. In recent years, quantum state verification has received increasing attention, yet the challenge of addressing noise effects in implementing this approach remains unsolved. In this work, a systematic assessment of the performance of quantum state verification protocols is provided in the presence of measurement noise. Based on the analysis, a necessary and sufficient condition is provided to uniquely identify the target state under noisy measurements. Moreover, this work proposes a symmetric hypothesis testing verification algorithm with noisy measurements. Then, relying on <span></span><math>\u0000 <semantics>\u0000 <mi>W</mi>\u0000 <annotation>$W$</annotation>\u0000 </semantics></math> states, a semidefinite program is demonstrated to calculate the infidelity threshold for arbitrary measurement noise. Subsequently, using a noisy nonadaptive verification strategy of Greenberger–Horne–Zeilinger and stabilizer states, the noise effects on the verification efficiency are analytically illustrated. From both analytical and numerical perspectives, this work demonstrates that the noisy verification protocol exhibits a negative quadratic relationship between the sample complexity and the infidelity. The method can be easily applied to real experimental settings, thereby demonstrating its promising prospects.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 9","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145062516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One-Step Implementation of Time-Optimal Three-Qubit Nonadiabatic Holonomic Gates via Dipole–Dipole Interaction in Rydberg Atoms","authors":"Shuai Liu,&nbsp;Han Yang,&nbsp;Jia-Xi Qin,&nbsp;Du Ran,&nbsp;Yi-Hao Kang,&nbsp;Yan Xia","doi":"10.1002/qute.202400542","DOIUrl":"10.1002/qute.202400542","url":null,"abstract":"<p>In this study, a one-step scheme is proposed to implement time-optimal three-qubit nonadiabatic holonomic gates using unconventional Rydberg pumping mechanism. The system dynamics of three Rydberg atoms are investigated in the regime of dipole–dipole interaction, which may provide relatively strong interaction strengths. By analyzing the system dynamics of three atoms, an effective three-level interaction Hamiltonian is derived. Based on this, a three-qubit nonadiabatic holonomic gate can be implemented in one step by modulating Rabi frequencies of control pulses on the target atom. The scheme is further optimized using time-optimal control technology based on quantum-brachistochrone formalism, which minimizes the evolution time of the system and mitigates the influence from the environmental decoherence. Numerical simulations results show that the scheme is robust against the Doppler dephasing error, system parameter variations, and atomic spontaneous emissions. Therefore, it is hoped that the scheme may facilitate the realization of fault-tolerant quantum computation in Rydberg atoms.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"8 8","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144833305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}