Pub Date : 2025-06-16DOI: 10.1109/TQE.2025.3580377
Job van Staveren;Luc Enthoven;Peter Luka Bavdaz;Marcel Meyer;Corentin Déprez;Ville Nuutinen;Russell Lake;Davide Degli Esposti;Cornelius Carlsson;Alberto Tosato;Jiang Gong;Bagas Prabowo;Masoud Babaie;Carmen G. Almudever;Menno Veldhorst;Giordano Scappucci;Fabio Sebastiano
The rapidly growing number of qubits in semiconductor quantum computers requires a scalable control interface, including the efficient generation of dc bias voltages for gate electrodes. To avoid unrealistically complex wiring between any room-temperature electronics and the cryogenic qubits, this article presents an integrated cryogenic solution for the bias-voltage generation and distribution for large-scale semiconductor spin-qubit quantum processors. A dedicated cryogenic CMOS (cryo-CMOS) demultiplexer and a cryo-CMOS dc digital-to-analog converter (DAC) have been developed in a 22-nm fin field-effect transistor process to control a codeveloped 2-D array designed with 648 single-hole transistors. Thanks to the dissipation below $120 ,mathrm{mu }mathrm{W}$, the whole system operates at temperatures below $70 ,mathrm{m}mathrm{K}$ in a custom-built electrical/mechanical infrastructure embedded in a standard single-pulse-tube dilution refrigerator. The bias voltages generated by the cryo-CMOS DAC are demultiplexed to sample-and-hold structures, allowing to store 96 unique bias voltages over a $3 ,mathrm{V}$ range with a voltage drift between $60 ,mathrm{mu }mathrm{V}/ mathrm{s}$ and $18 ,mathrm{m}mathrm{V}/ mathrm{s}$. This work demonstrates a tight integration at $,mathrm{m}mathrm{K}$ temperatures of cryo-CMOS bias generation and distribution with a dedicated large-scale quantum device. This showcases how this approach simplifies the wiring to the electronics, thus facilitating the scaling up of quantum processors toward the large number of qubits required for a practical quantum computer.
{"title":"Cryo-CMOS Bias-Voltage Generation and Demultiplexing at mK Temperatures for Large-Scale Arrays of Quantum Devices","authors":"Job van Staveren;Luc Enthoven;Peter Luka Bavdaz;Marcel Meyer;Corentin Déprez;Ville Nuutinen;Russell Lake;Davide Degli Esposti;Cornelius Carlsson;Alberto Tosato;Jiang Gong;Bagas Prabowo;Masoud Babaie;Carmen G. Almudever;Menno Veldhorst;Giordano Scappucci;Fabio Sebastiano","doi":"10.1109/TQE.2025.3580377","DOIUrl":"https://doi.org/10.1109/TQE.2025.3580377","url":null,"abstract":"The rapidly growing number of qubits in semiconductor quantum computers requires a scalable control interface, including the efficient generation of dc bias voltages for gate electrodes. To avoid unrealistically complex wiring between any room-temperature electronics and the cryogenic qubits, this article presents an integrated cryogenic solution for the bias-voltage generation and distribution for large-scale semiconductor spin-qubit quantum processors. A dedicated cryogenic CMOS (cryo-CMOS) demultiplexer and a cryo-CMOS dc digital-to-analog converter (DAC) have been developed in a 22-nm fin field-effect transistor process to control a codeveloped 2-D array designed with 648 single-hole transistors. Thanks to the dissipation below <inline-formula><tex-math>$120 ,mathrm{mu }mathrm{W}$</tex-math></inline-formula>, the whole system operates at temperatures below <inline-formula><tex-math>$70 ,mathrm{m}mathrm{K}$</tex-math></inline-formula> in a custom-built electrical/mechanical infrastructure embedded in a standard single-pulse-tube dilution refrigerator. The bias voltages generated by the cryo-CMOS DAC are demultiplexed to sample-and-hold structures, allowing to store 96 unique bias voltages over a <inline-formula><tex-math>$3 ,mathrm{V}$</tex-math></inline-formula> range with a voltage drift between <inline-formula><tex-math>$60 ,mathrm{mu }mathrm{V}/ mathrm{s}$</tex-math></inline-formula> and <inline-formula><tex-math>$18 ,mathrm{m}mathrm{V}/ mathrm{s}$</tex-math></inline-formula>. This work demonstrates a tight integration at <inline-formula><tex-math>$,mathrm{m}mathrm{K}$</tex-math></inline-formula> temperatures of cryo-CMOS bias generation and distribution with a dedicated large-scale quantum device. This showcases how this approach simplifies the wiring to the electronics, thus facilitating the scaling up of quantum processors toward the large number of qubits required for a practical quantum computer.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-18"},"PeriodicalIF":0.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11037551","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144646673","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}
Pub Date : 2025-06-06DOI: 10.1109/TQE.2025.3577769
Jiahan Chen;Zhengzhong Yi;Zhipeng Liang;Xuan Wang
Quantum error correction is crucial for universal fault-tolerant quantum computing. Highly accurate and low-time-complexity decoding algorithms play an indispensable role in ensuring quantum error correction works effectively. Among existing decoding algorithms, belief propagation (BP) is notable for its nearly linear time complexity and general applicability to stabilizer codes. However, BP's decoding accuracy without postprocessing is unsatisfactory in most situations. This article focuses on improving the decoding accuracy of BP over GF(4) for surface codes. Inspired by machine learning optimization techniques, we first propose Momentum-BP and AdaGrad-BP to reduce oscillations in message updating, breaking the trapping sets of surface codes. We further propose exponential weighted average initialization belief propagation (EWAInit-BP), which adaptively updates initial probabilities and provides a one to three orders of magnitude improvement over traditional BP for planar surface code, toric code, and $XZZX$ surface code without any postprocessing method, showing high decoding accuracy even under parallel scheduling. The theoretical $O(1)$ time complexity under parallel implementation and high accuracy of EWAInit-BP make it a promising candidate for high-precision real-time decoders.
量子纠错是通用容错量子计算的关键。高精度、低时间复杂度的译码算法是保证量子纠错有效进行的必要条件。在现有的译码算法中，信念传播算法（BP）具有近似线性的时间复杂度和对稳定器码的普遍适用性。然而，在大多数情况下，未经后处理的BP解码精度并不令人满意。本文主要研究如何提高BP over GF(4)对表面码的译码精度。受机器学习优化技术的启发，我们首先提出了Momentum-BP和AdaGrad-BP来减少消息更新中的振荡，打破表面代码的捕获集。我们进一步提出指数加权平均初始化信念传播（EWAInit-BP），该方法自适应更新初始概率，并在没有任何后处理方法的情况下，对平面码、环面码和$XZZX$面码提供了比传统BP 1到3个数量级的改进，即使在并行调度下也具有较高的解码精度。并行实现下的理论时间复杂度$O(1)$和较高的精度使EWAInit-BP成为高精度实时解码器的理想选择。
{"title":"Improved Belief Propagation Decoding Algorithms for Surface Codes","authors":"Jiahan Chen;Zhengzhong Yi;Zhipeng Liang;Xuan Wang","doi":"10.1109/TQE.2025.3577769","DOIUrl":"https://doi.org/10.1109/TQE.2025.3577769","url":null,"abstract":"Quantum error correction is crucial for universal fault-tolerant quantum computing. Highly accurate and low-time-complexity decoding algorithms play an indispensable role in ensuring quantum error correction works effectively. Among existing decoding algorithms, belief propagation (BP) is notable for its nearly linear time complexity and general applicability to stabilizer codes. However, BP's decoding accuracy without postprocessing is unsatisfactory in most situations. This article focuses on improving the decoding accuracy of BP over GF(4) for surface codes. Inspired by machine learning optimization techniques, we first propose Momentum-BP and AdaGrad-BP to reduce oscillations in message updating, breaking the trapping sets of surface codes. We further propose exponential weighted average initialization belief propagation (EWAInit-BP), which adaptively updates initial probabilities and provides a one to three orders of magnitude improvement over traditional BP for planar surface code, toric code, and <inline-formula><tex-math>$XZZX$</tex-math></inline-formula> surface code without any postprocessing method, showing high decoding accuracy even under parallel scheduling. The theoretical <inline-formula><tex-math>$O(1)$</tex-math></inline-formula> time complexity under parallel implementation and high accuracy of EWAInit-BP make it a promising candidate for high-precision real-time decoders.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11027786","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687710","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}
Many search-based quantum algorithms that achieve a theoretical speedup are not practically relevant since they require extraordinarily long coherence times, or lack the parallelizability of their classical counterparts. This raises the question of how to divide computational tasks into a collection of parallelizable subproblems, each of which can be solved by a quantum computer with limited coherence time. Here, we approach this question via hybrid algorithms for the $k$-satisfiability problem (k-SAT). Our analysis is based on Schöning's algorithm, which solves instances of $k$-SAT by performing random walks in the space of potential assignments. The search space of the walk allows for “natural” partitions, where we subject only one part of the partition to a Grover search, while the rest is sampled classically, thus resulting in a hybrid scheme. In this setting, we argue that there exists a simple tradeoff relation between the total runtime and the coherence time, which no such partition-based hybrid scheme can surpass. For several concrete choices of partitions, we explicitly determine the specific runtime coherence time relations and show saturation of the ideal tradeoff. Finally, we present numerical simulations, which suggest additional flexibility in implementing hybrid algorithms with the optimal tradeoff.
{"title":"Runtime–Coherence Tradeoffs for Hybrid Satisfiability Solvers","authors":"Vahideh Eshaghian;Sören Wilkening;Johan Åberg;David Gross","doi":"10.1109/TQE.2025.3563805","DOIUrl":"https://doi.org/10.1109/TQE.2025.3563805","url":null,"abstract":"Many search-based quantum algorithms that achieve a theoretical speedup are not practically relevant since they require extraordinarily long coherence times, or lack the parallelizability of their classical counterparts. This raises the question of how to divide computational tasks into a collection of parallelizable subproblems, each of which can be solved by a quantum computer with limited coherence time. Here, we approach this question via hybrid algorithms for the <inline-formula><tex-math>$k$</tex-math></inline-formula>-satisfiability problem (k-SAT). Our analysis is based on Schöning's algorithm, which solves instances of <inline-formula><tex-math>$k$</tex-math></inline-formula>-SAT by performing random walks in the space of potential assignments. The search space of the walk allows for “natural” partitions, where we subject only one part of the partition to a Grover search, while the rest is sampled classically, thus resulting in a hybrid scheme. In this setting, we argue that there exists a simple tradeoff relation between the total runtime and the coherence time, which no such partition-based hybrid scheme can surpass. For several concrete choices of partitions, we explicitly determine the specific runtime coherence time relations and show saturation of the ideal tradeoff. Finally, we present numerical simulations, which suggest additional flexibility in implementing hybrid algorithms with the optimal tradeoff.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-22"},"PeriodicalIF":0.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10974582","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148131","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}
Pub Date : 2025-04-15DOI: 10.1109/TQE.2025.3560403
Mohammad Amir Dastgheib;Jawad A. Salehi;Mohammad Rezai
This article describes the fundamental principles and mathematical foundations of quantum direct-sequence spread-spectrum code division multiple-access communication systems. The evolution of quantum signals through the quantum direct-sequence spread-spectrum multiple-access communication system is carefully characterized by a novel approach called the decomposition of creation operators. In this methodology, the creation operator of the transmitted quantum signal is decomposed into the chip-time interval creation operators, each of which is defined over the duration of a chip. These chip-time interval creation operators are the invariant building blocks of the spread-spectrum quantum communication systems. With the aid of the proposed chip-time decomposition approach, we can find closed-form relations for quantum signals at the receiver of such a quantum communication system. Furthermore, this article details the principles of narrowband filtering of quantum signals required at the receiver, a crucial step in designing and analyzing quantum communication systems. We show, that by employing coherent states as the transmitted quantum signals, the interuser interference appears as an additive term in the magnitude of the output coherent (Glauber) state, and the output of the quantum communication system is a pure quantum signal. On the other hand, if the transmitters utilize particle-like quantum signals (Fock states) such as single-photon states, the entanglement effect can arise at the receivers. The important techniques developed in this article are expected to have far-reaching implications for various applications in the exciting field of quantum communications and quantum signal processing.
{"title":"Quantum Direct-Sequence Spread-Spectrum CDMA Communication Systems: Mathematical Foundations","authors":"Mohammad Amir Dastgheib;Jawad A. Salehi;Mohammad Rezai","doi":"10.1109/TQE.2025.3560403","DOIUrl":"https://doi.org/10.1109/TQE.2025.3560403","url":null,"abstract":"This article describes the fundamental principles and mathematical foundations of quantum direct-sequence spread-spectrum code division multiple-access communication systems. The evolution of quantum signals through the quantum direct-sequence spread-spectrum multiple-access communication system is carefully characterized by a novel approach called the decomposition of creation operators. In this methodology, the creation operator of the transmitted quantum signal is decomposed into the chip-time interval creation operators, each of which is defined over the duration of a chip. These chip-time interval creation operators are the invariant building blocks of the spread-spectrum quantum communication systems. With the aid of the proposed chip-time decomposition approach, we can find closed-form relations for quantum signals at the receiver of such a quantum communication system. Furthermore, this article details the principles of narrowband filtering of quantum signals required at the receiver, a crucial step in designing and analyzing quantum communication systems. We show, that by employing coherent states as the transmitted quantum signals, the interuser interference appears as an additive term in the magnitude of the output coherent (Glauber) state, and the output of the quantum communication system is a pure quantum signal. On the other hand, if the transmitters utilize particle-like quantum signals (Fock states) such as single-photon states, the entanglement effect can arise at the receivers. The important techniques developed in this article are expected to have far-reaching implications for various applications in the exciting field of quantum communications and quantum signal processing.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-40"},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10964196","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072826","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}
Quantum Hamiltonian simulation is one of the most promising applications of quantum computing and forms the basis for many quantum algorithms. Benchmarking them is an important gauge of progress in quantum computing technology. We present a methodology and software framework to evaluate various facets of the performance of gate-based quantum computers on Trotterized quantum Hamiltonian evolution. We propose three distinct modes for benchmarking: 1) comparing simulation on a real device to that on a noiseless classical simulator; 2) comparing simulation on a real device with exact diagonalization results; and 3) using scalable mirror circuit techniques to assess hardware performance in scenarios beyond classical simulation methods. We demonstrate this framework on five Hamiltonian models from the HamLib library: the Fermi–Hubbard and Bose–Hubbard models, the transverse-field Ising model, the Heisenberg model, and the Max3SAT problem. Experiments were conducted using Qiskit's Aer simulator, BlueQubit's CPU cluster and GPU simulators, and IBM's quantum hardware. Our framework, extendable to other Hamiltonians, provides comprehensive performance profiles that reveal hardware and algorithmic limitations and measure both fidelity and execution times, identifying crossover points where quantum hardware outperforms CPU/GPU simulators.
{"title":"A Comprehensive Cross-Model Framework for Benchmarking the Performance of Quantum Hamiltonian Simulations","authors":"Avimita Chatterjee;Sonny Rappaport;Anish Giri;Sonika Johri;Timothy Proctor;David E. Bernal Neira;Pratik Sathe;Thomas Lubinski","doi":"10.1109/TQE.2025.3558090","DOIUrl":"https://doi.org/10.1109/TQE.2025.3558090","url":null,"abstract":"Quantum Hamiltonian simulation is one of the most promising applications of quantum computing and forms the basis for many quantum algorithms. Benchmarking them is an important gauge of progress in quantum computing technology. We present a methodology and software framework to evaluate various facets of the performance of gate-based quantum computers on Trotterized quantum Hamiltonian evolution. We propose three distinct modes for benchmarking: 1) comparing simulation on a real device to that on a noiseless classical simulator; 2) comparing simulation on a real device with exact diagonalization results; and 3) using scalable mirror circuit techniques to assess hardware performance in scenarios beyond classical simulation methods. We demonstrate this framework on five Hamiltonian models from the HamLib library: the Fermi–Hubbard and Bose–Hubbard models, the transverse-field Ising model, the Heisenberg model, and the Max3SAT problem. Experiments were conducted using Qiskit's Aer simulator, BlueQubit's CPU cluster and GPU simulators, and IBM's quantum hardware. Our framework, extendable to other Hamiltonians, provides comprehensive performance profiles that reveal hardware and algorithmic limitations and measure both fidelity and execution times, identifying crossover points where quantum hardware outperforms CPU/GPU simulators.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-26"},"PeriodicalIF":0.0,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10949677","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896182","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}
In this article, we propose a new strategy to exploit Grover's algorithm for unstructured search problems. We first show that running Grover's routine with a reduced number of iterations but allowing several trials presents a complexity advantage while keeping the same success probability. Then, by a theoretical analysis of the performance, we provide a generic procedure to parameterize the number of iterations $k$ within one shot of Grover's algorithm and the maximum number of trials $T$, given a targeted success $p$ and the size of the database $N$. At the end, we highlight that this new approach permits to reduce the computational time by at least 10% for $p geq 0.999$ independently of the size of the database.
在本文中，我们提出了一种利用Grover算法解决非结构化搜索问题的新策略。我们首先表明，在保持相同成功概率的情况下，通过减少迭代次数但允许多次试验来运行Grover例程具有复杂性优势。然后，通过对性能的理论分析，我们提供了一个通用的过程来参数化Grover算法的一次迭代次数$k$和最大试验次数$T$，给定目标成功$p$和数据库大小$N$。最后，我们强调这种新方法可以将计算时间减少至少10％% for $p geq 0.999$ independently of the size of the database.
{"title":"Mixed Grover: A Hybrid Version to Improve Grover's Algorithm for Unstructured Database Search","authors":"Romain Piron;Muhammad Idham Habibie;Claire Goursaud","doi":"10.1109/TQE.2025.3555562","DOIUrl":"https://doi.org/10.1109/TQE.2025.3555562","url":null,"abstract":"In this article, we propose a new strategy to exploit Grover's algorithm for unstructured search problems. We first show that running Grover's routine with a reduced number of iterations but allowing several trials presents a complexity advantage while keeping the same success probability. Then, by a theoretical analysis of the performance, we provide a generic procedure to parameterize the number of iterations <inline-formula><tex-math>$k$</tex-math></inline-formula> within one shot of Grover's algorithm and the maximum number of trials <inline-formula><tex-math>$T$</tex-math></inline-formula>, given a targeted success <inline-formula><tex-math>$p$</tex-math></inline-formula> and the size of the database <inline-formula><tex-math>$N$</tex-math></inline-formula>. At the end, we highlight that this new approach permits to reduce the computational time by at least 10% for <inline-formula><tex-math>$p geq 0.999$</tex-math></inline-formula> independently of the size of the database.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10944580","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875211","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}
Pub Date : 2025-03-28DOI: 10.1109/TQE.2025.3574463
Jan Ole Ernst;Jan Snoeijs;Mitchell Peaks;Jochen Wolf
Radio frequency pulses are preponderant for the control of quantum bits and the execution of operations in quantum computers. The ability to fine-tune key pulse parameters, such as time-dependent amplitude, phase, and frequency, is essential to achieve maximal gate fidelity and mitigate errors. As systems increase in scale, a larger proportion of the control electronic processing will move closer to the qubits, to enhance integration and minimize latency in operations requiring fast feedback. This will constrain the space available in the memory of the control electronics to load time-resolved pulse parameters at high sampling rates. Cubic spline interpolation is a powerful and commonly used technique that divides the pulse into segments of cubic polynomials. We show an optimized implementation of this strategy, using a two-stage curve-fitting process and additional symmetry operations to load a high-sampling pulse output on an field-programmable gate array. This results in a favorable accuracy-versus-memory-footprint tradeoff. By simulating single-qubit population transfer and atom transport on a neutral-atom device, we show that high fidelities can be achieved with low memory requirements. This is instrumental for scaling up the number of qubits and gate operations in environments where memory is a limited resource.
{"title":"Memory-Optimized Cubic Splines for High-Fidelity Quantum Operations","authors":"Jan Ole Ernst;Jan Snoeijs;Mitchell Peaks;Jochen Wolf","doi":"10.1109/TQE.2025.3574463","DOIUrl":"https://doi.org/10.1109/TQE.2025.3574463","url":null,"abstract":"Radio frequency pulses are preponderant for the control of quantum bits and the execution of operations in quantum computers. The ability to fine-tune key pulse parameters, such as time-dependent amplitude, phase, and frequency, is essential to achieve maximal gate fidelity and mitigate errors. As systems increase in scale, a larger proportion of the control electronic processing will move closer to the qubits, to enhance integration and minimize latency in operations requiring fast feedback. This will constrain the space available in the memory of the control electronics to load time-resolved pulse parameters at high sampling rates. Cubic spline interpolation is a powerful and commonly used technique that divides the pulse into segments of cubic polynomials. We show an optimized implementation of this strategy, using a two-stage curve-fitting process and additional symmetry operations to load a high-sampling pulse output on an field-programmable gate array. This results in a favorable accuracy-versus-memory-footprint tradeoff. By simulating single-qubit population transfer and atom transport on a neutral-atom device, we show that high fidelities can be achieved with low memory requirements. This is instrumental for scaling up the number of qubits and gate operations in environments where memory is a limited resource.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11016810","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597798","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}
This article proposes a novel beam selection method using a multiarmed bandit (MAB) algorithm based on a quantum walk (QW) principle, aimed at improving system performance. A massive multiple-input multiple-output system, employing multiple high-gain beams within a high-frequency band, is indispensable for achieving large capacity in future wireless communications. However, as the number of beams increases, selecting the most appropriate beam for each user becomes challenging due to the extensive search space and necessitating the development of a more efficient beam selection method. Therefore, we formulate a systematic process for beam selection employing the MAB algorithm rooted in QW principles. We derive the optimal parameters of this method to maximize achievable channel capacity. Through numerical analysis, we validate that the proposed method yields a greater channel capacity than that achieved not only by traditional MAB algorithms but also by an exhaustive search with overhead.
{"title":"Two-Dimensional Beam Selection by Multiarmed Bandit Algorithm Based on a Quantum Walk","authors":"Maki Arai;Tomoki Yamagami;Takatomo Mihana;Ryoichi Horisaki;Mikio Hasegawa","doi":"10.1109/TQE.2025.3555145","DOIUrl":"https://doi.org/10.1109/TQE.2025.3555145","url":null,"abstract":"This article proposes a novel beam selection method using a multiarmed bandit (MAB) algorithm based on a quantum walk (QW) principle, aimed at improving system performance. A massive multiple-input multiple-output system, employing multiple high-gain beams within a high-frequency band, is indispensable for achieving large capacity in future wireless communications. However, as the number of beams increases, selecting the most appropriate beam for each user becomes challenging due to the extensive search space and necessitating the development of a more efficient beam selection method. Therefore, we formulate a systematic process for beam selection employing the MAB algorithm rooted in QW principles. We derive the optimal parameters of this method to maximize achievable channel capacity. Through numerical analysis, we validate that the proposed method yields a greater channel capacity than that achieved not only by traditional MAB algorithms but also by an exhaustive search with overhead.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10938938","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875212","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}
Pub Date : 2025-03-23DOI: 10.1109/TQE.2025.3572764
Pei-Hao Liou;Ching-Yi Lai
Given that quantum error correction processes are unreliable, an efficient error syndrome extraction circuit should use fewer ancillary qubits, quantum gates, and measurements while maintaining low circuit depth, to minimize the circuit area, roughly defined as the product of circuit depth and the number of physical qubits. We propose to design parallel flagged syndrome extraction with shared flag qubits for quantum stabilizer codes. Versatile parallelization techniques are employed to minimize the required circuit area, thereby improving the error threshold and overall performance. Specifically, measurement outcomes across multiple rounds of syndrome extraction are integrated into a lookup table decoder, enabling parallelization of multiple stabilizer measurements with shared flag qubits. In addition, we introduce an adaptive technique to reduce the overhead from excessive syndrome extraction. We present flag-sharing and fully parallel schemes for the $[![17,1,5]!]$, $[![19,1,5]!]$ Calderbank–Shor–Steane (CSS) codes and the $[![5,1,3]!]$ non-CSS code, where the $[![5,1,3]!]$ implementation achieves the minimum known circuit area. Numerical simulations have demonstrated improved pseudothresholds for these codes by up to an order of magnitude compared to previous schemes in the literature.
{"title":"Reducing Quantum Error Correction Overhead With Versatile Flag-Sharing Syndrome Extraction Circuits","authors":"Pei-Hao Liou;Ching-Yi Lai","doi":"10.1109/TQE.2025.3572764","DOIUrl":"https://doi.org/10.1109/TQE.2025.3572764","url":null,"abstract":"Given that quantum error correction processes are unreliable, an efficient error syndrome extraction circuit should use fewer ancillary qubits, quantum gates, and measurements while maintaining low circuit depth, to minimize the circuit area, roughly defined as the product of circuit depth and the number of physical qubits. We propose to design parallel flagged syndrome extraction with shared flag qubits for quantum stabilizer codes. Versatile parallelization techniques are employed to minimize the required circuit area, thereby improving the error threshold and overall performance. Specifically, measurement outcomes across multiple rounds of syndrome extraction are integrated into a lookup table decoder, enabling parallelization of multiple stabilizer measurements with shared flag qubits. In addition, we introduce an adaptive technique to reduce the overhead from excessive syndrome extraction. We present flag-sharing and fully parallel schemes for the <inline-formula><tex-math>$[![17,1,5]!]$</tex-math></inline-formula>, <inline-formula><tex-math>$[![19,1,5]!]$</tex-math></inline-formula> Calderbank–Shor–Steane (CSS) codes and the <inline-formula><tex-math>$[![5,1,3]!]$</tex-math></inline-formula> non-CSS code, where the <inline-formula><tex-math>$[![5,1,3]!]$</tex-math></inline-formula> implementation achieves the minimum known circuit area. Numerical simulations have demonstrated improved pseudothresholds for these codes by up to an order of magnitude compared to previous schemes in the literature.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-24"},"PeriodicalIF":0.0,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11011921","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366999","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}
Pub Date : 2025-03-20DOI: 10.1109/TQE.2025.3572142
Yikai Mao;Shaswot Shresthamali;Masaaki Kondo
Unlike most classical algorithms that take an input and give the solution directly as an output, quantum algorithms produce a quantum circuit that works as an indirect solution to computationally hard problems. In the full quantum computing workflow, most data processing remains in the classical domain except for running the quantum circuit in the quantum processor. This leaves massive opportunities for classical automation and optimization toward future utilization of quantum computing. We kick-start the first step in this direction by introducing Q-gen, a high-level parameterized quantum circuit generator incorporating 15 realistic quantum algorithms. Each customized generation function comes with algorithm-specific parameters beyond the number of qubits, providing a large generation volume with high circuit variability. To demonstrate the functionality of Q-gen, we organize the algorithms into five hierarchical systems and generate a quantum circuit dataset accompanied by their measurement histograms and state vectors. This dataset enables researchers to statistically analyze the structure, complexity, and performance of large-scale quantum circuits or quickly train novel machine learning models without worrying about the exponentially growing simulation time. Q-gen is an open-source and multipurpose project that serves as the entrance for users with a classical computer science background to dive into the world of quantum computing.
{"title":"Q-Gen: A Parameterized Quantum Circuit Generator","authors":"Yikai Mao;Shaswot Shresthamali;Masaaki Kondo","doi":"10.1109/TQE.2025.3572142","DOIUrl":"https://doi.org/10.1109/TQE.2025.3572142","url":null,"abstract":"Unlike most classical algorithms that take an input and give the solution directly as an output, quantum algorithms produce a quantum circuit that works as an indirect solution to computationally hard problems. In the full quantum computing workflow, most data processing remains in the classical domain except for running the quantum circuit in the quantum processor. This leaves massive opportunities for classical automation and optimization toward future utilization of quantum computing. We kick-start the first step in this direction by introducing Q-gen, a high-level parameterized quantum circuit generator incorporating 15 realistic quantum algorithms. Each customized generation function comes with algorithm-specific parameters beyond the number of qubits, providing a large generation volume with high circuit variability. To demonstrate the functionality of Q-gen, we organize the algorithms into five hierarchical systems and generate a quantum circuit dataset accompanied by their measurement histograms and state vectors. This dataset enables researchers to statistically analyze the structure, complexity, and performance of large-scale quantum circuits or quickly train novel machine learning models without worrying about the exponentially growing simulation time. Q-gen is an open-source and multipurpose project that serves as the entrance for users with a classical computer science background to dive into the world of quantum computing.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11008486","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144314762","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}
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