Pub Date : 2025-10-08DOI: 10.1109/TQE.2025.3619387
Iago Fernández Llovo;Guillermo Díaz-Camacho;Natalia Costas Lago;Andrés Gómez Tato
Distributed quantum computing relies on coordinated operations between remote quantum processing units (QPUs), yet most existing work either assumes full connectivity, unrealistic for large networks, or relies on entanglement swapping. To mitigate the overhead of communication, we propose a scheme for the distribution of collective quantum operations among remote QPUs by exploiting distributed fan-out operations to a central node in network architectures similar to those used for high-performance computing, which requires only preshared entanglement, local operations, and classical communication. We show that a general diagonal gate can be distributed among any number of nodes and provide the ebit cost bounds. For a single distributed multicontrolled gate, this amounts to a single additional Bell pair over the theoretically optimal calculation with all-to-all preshared entanglement, demonstrating better scalability when compared to current proposals based on entanglement swapping through a network. We provide a recipe for the lumped distribution of gates, such as arbitrarily sized Toffoli and multicontrolled Z and $R_{zz}(theta)$ gates. Finally, we provide an exact implementation of a distributed Grover's search algorithm using this protocol to partition the circuit, with Bell pair cost growing linearly with the number of Grover iterations and the number of partitions, and show how these techniques can be applied to other algorithms, such as quantum approximate optimization algorithm. Our results show that alternative approaches to entanglement swapping can provide major benefits in distributed quantum computing, pointing to promising avenues for future research.
{"title":"Network-Assisted Collective Operations for Efficient Distributed Quantum Computing","authors":"Iago Fernández Llovo;Guillermo Díaz-Camacho;Natalia Costas Lago;Andrés Gómez Tato","doi":"10.1109/TQE.2025.3619387","DOIUrl":"https://doi.org/10.1109/TQE.2025.3619387","url":null,"abstract":"Distributed quantum computing relies on coordinated operations between remote quantum processing units (QPUs), yet most existing work either assumes full connectivity, unrealistic for large networks, or relies on entanglement swapping. To mitigate the overhead of communication, we propose a scheme for the distribution of collective quantum operations among remote QPUs by exploiting distributed fan-out operations to a central node in network architectures similar to those used for high-performance computing, which requires only preshared entanglement, local operations, and classical communication. We show that a general diagonal gate can be distributed among any number of nodes and provide the ebit cost bounds. For a single distributed multicontrolled gate, this amounts to a single additional Bell pair over the theoretically optimal calculation with all-to-all preshared entanglement, demonstrating better scalability when compared to current proposals based on entanglement swapping through a network. We provide a recipe for the lumped distribution of gates, such as arbitrarily sized Toffoli and multicontrolled Z and <inline-formula><tex-math>$R_{zz}(theta)$</tex-math></inline-formula> gates. Finally, we provide an exact implementation of a distributed Grover's search algorithm using this protocol to partition the circuit, with Bell pair cost growing linearly with the number of Grover iterations and the number of partitions, and show how these techniques can be applied to other algorithms, such as quantum approximate optimization algorithm. Our results show that alternative approaches to entanglement swapping can provide major benefits in distributed quantum computing, pointing to promising avenues for future research.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-14"},"PeriodicalIF":4.6,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11197054","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455902","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 key distribution (QKD) is a technology for distributing cryptographic keys between two communication parties based on the quantum physics for the secure communication. A trusted node-based key relay technique is integrated with QKD to overcome the technical limitations of QKD and to enable key distribution between two arbitrary communication parties in the trusted node network, which we refer to as the QKD network. In addition, secret-sharing technology has been integrated with the QKD network to realize secure data storage and secure data communication, which we call a quantum secure cloud. This article presents the development and evaluation of the proof-of-concept (PoC) system for the QKD network and a quantum secure cloud, especially applied to the genome medicine domain. The PoC system was developed at Tohoku University and Toshiba sites to address the “cancer clinical sequencing” use case. We evaluated three practical scenarios with the PoC system: 1) real-time transmission of genome analysis data; 2) “expert panel,” an online video conference for medical experts’ discussion; and 3) distributed backup of genome analysis data. To support these scenarios, we developed three new functions: 1) a function for monitoring output data and pipeline processing of data encryption/decryption and transmission for secure large-scale data transfer; 2) a key management system function to achieve both large-scale data transmission and low-latency data communication; and 3) a function for preemptive key data reading and direct access to storage devices to enable high-speed data transmission and distributed data backup using a secret-sharing scheme. These scenarios and functions were evaluated and demonstrated using real or simulated genome data. The evaluation results reveal that QKD network and quantum secure cloud technologies can be applied to cancer clinical sequencing as a use case of the genome medicine domain.
{"title":"Quantum Key Distribution Network and Quantum Secure Cloud Technologies for Genome Medicine Use Cases","authors":"Yoshimichi Tanizawa;Akira Murakami;Ririka Takahashi;Kazuaki Doi;Mamiko Kujiraoka;Hideaki Sato;Muneaki Shimada;Nobuo Yaegashi;Shogo Shigeta;Yasunobu Okamura;Kengo Kinoshita;Fumiki Katsuoka;Inaho Danjoh;Fuji Nagami;Masayuki Yamamoto;Mikio Fujiwara","doi":"10.1109/TQE.2025.3611335","DOIUrl":"https://doi.org/10.1109/TQE.2025.3611335","url":null,"abstract":"Quantum key distribution (QKD) is a technology for distributing cryptographic keys between two communication parties based on the quantum physics for the secure communication. A trusted node-based key relay technique is integrated with QKD to overcome the technical limitations of QKD and to enable key distribution between two arbitrary communication parties in the trusted node network, which we refer to as the QKD network. In addition, secret-sharing technology has been integrated with the QKD network to realize secure data storage and secure data communication, which we call a quantum secure cloud. This article presents the development and evaluation of the proof-of-concept (PoC) system for the QKD network and a quantum secure cloud, especially applied to the genome medicine domain. The PoC system was developed at Tohoku University and Toshiba sites to address the “cancer clinical sequencing” use case. We evaluated three practical scenarios with the PoC system: 1) real-time transmission of genome analysis data; 2) “expert panel,” an online video conference for medical experts’ discussion; and 3) distributed backup of genome analysis data. To support these scenarios, we developed three new functions: 1) a function for monitoring output data and pipeline processing of data encryption/decryption and transmission for secure large-scale data transfer; 2) a key management system function to achieve both large-scale data transmission and low-latency data communication; and 3) a function for preemptive key data reading and direct access to storage devices to enable high-speed data transmission and distributed data backup using a secret-sharing scheme. These scenarios and functions were evaluated and demonstrated using real or simulated genome data. The evaluation results reveal that QKD network and quantum secure cloud technologies can be applied to cancer clinical sequencing as a use case of the genome medicine domain.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-15"},"PeriodicalIF":4.6,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11169437","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455749","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 : 2025-09-11DOI: 10.1109/TQE.2025.3604712
Giuseppe Di Guglielmo;Botao Du;Javier Campos;Alexandra Boltasseva;Akash Dixit;Farah Fahim;Zhaxylyk Kudyshev;Santiago Lopez;Ruichao Ma;Gabriel N. Perdue;Nhan Tran;Omer Yesilyurt;Daniel Bowring
In this article, we present an end-to-end workflow for superconducting qubit readout that embeds codesigned neural networks into the quantum instrumentation control kit (QICK). Capitalizing on the custom firmware and software of the QICK platform, which is built on Xilinx radiofrequency system-on-chip field-programmable gate arrays (FPGAs), we aim to leverage machine learning (ML) to address critical challenges in qubit readout accuracy and scalability. The workflow utilizes the hls4ml package and employs quantization-aware training to translate ML models into hardware-efficient FPGA implementations via user-friendly Python application programming interfaces. We experimentally demonstrate the design, optimization, and integration of an ML algorithm for single transmon qubit readout, achieving 96% single-shot fidelity with a latency of 32.25 ns and less than 16% FPGA lookup table resource utilization. Our results offer the community an accessible workflow to advance ML-driven readout and adaptive control in quantum information processing applications.
{"title":"End-to-End Workflow for Machine-Learning-Based Qubit Readout With QICK and hls4ml","authors":"Giuseppe Di Guglielmo;Botao Du;Javier Campos;Alexandra Boltasseva;Akash Dixit;Farah Fahim;Zhaxylyk Kudyshev;Santiago Lopez;Ruichao Ma;Gabriel N. Perdue;Nhan Tran;Omer Yesilyurt;Daniel Bowring","doi":"10.1109/TQE.2025.3604712","DOIUrl":"https://doi.org/10.1109/TQE.2025.3604712","url":null,"abstract":"In this article, we present an end-to-end workflow for superconducting qubit readout that embeds codesigned neural networks into the quantum instrumentation control kit (QICK). Capitalizing on the custom firmware and software of the QICK platform, which is built on Xilinx radiofrequency system-on-chip field-programmable gate arrays (FPGAs), we aim to leverage machine learning (ML) to address critical challenges in qubit readout accuracy and scalability. The workflow utilizes the <monospace>hls4ml</monospace> package and employs quantization-aware training to translate ML models into hardware-efficient FPGA implementations via user-friendly Python application programming interfaces. We experimentally demonstrate the design, optimization, and integration of an ML algorithm for single transmon qubit readout, achieving 96% single-shot fidelity with a latency of 32.25 ns and less than 16% FPGA lookup table resource utilization. Our results offer the community an accessible workflow to advance ML-driven readout and adaptive control in quantum information processing applications.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-10"},"PeriodicalIF":4.6,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11159596","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141599","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}
Reaching fault-tolerant quantum computation relies on the successful implementation of non-Clifford circuits with quantum error correction (QEC). In QEC, quantum gates and measurements encode quantum information into an error-protected Hilbert space, while classical processing decodes the measurements into logical errors. QEC non-Clifford gates pose the greatest computation challenge from the classical controller's perspective, as they require mid-circuit decoding-dependent feed-forward—modifying the physical gate sequence based on the decoding outcome of previous measurements within the same circuit. In this work, we introduce the first benchmarks to holistically evaluate the capability of a combined controller–decoder system to run non-Clifford QEC circuits. We show that executing an error-corrected non-Clifford circuit, comprised of numerous non-Clifford gates, strictly hinges upon the classical controller–decoder system. Particularly, its ability to perform decoding-based feed-forward with low latency, defined as the time between the last measurement required for decoding and the dependent mid-circuit quantum operation. We analyze how the system's latency dictates the circuit's operational regime: latency divergence, classical-controller-limited runtime, or quantum-operation-limited runtime. Based on this understanding, we introduce latency-based benchmarks to set a standard for developing QEC control systems as the essential components of fault-tolerant quantum computation.
{"title":"Benchmarking the Ability of a Controller to Execute Quantum Error Corrected Non-Clifford Circuits","authors":"Yaniv Kurman;Lior Ella;Ramon Szmuk;Oded Wertheim;Benedikt Dorschner;Sam Stanwyck;Yonatan Cohen","doi":"10.1109/TQE.2025.3608053","DOIUrl":"https://doi.org/10.1109/TQE.2025.3608053","url":null,"abstract":"Reaching fault-tolerant quantum computation relies on the successful implementation of non-Clifford circuits with quantum error correction (QEC). In QEC, quantum gates and measurements encode quantum information into an error-protected Hilbert space, while classical processing decodes the measurements into logical errors. QEC non-Clifford gates pose the greatest computation challenge from the classical controller's perspective, as they require mid-circuit decoding-dependent feed-forward—modifying the physical gate sequence based on the decoding outcome of previous measurements within the same circuit. In this work, we introduce the first benchmarks to holistically evaluate the capability of a combined controller–decoder system to run non-Clifford QEC circuits. We show that executing an error-corrected non-Clifford circuit, comprised of numerous non-Clifford gates, strictly hinges upon the classical controller–decoder system. Particularly, its ability to perform decoding-based feed-forward with low latency, defined as the time between the last measurement required for decoding and the dependent mid-circuit quantum operation. We analyze how the system's latency dictates the circuit's operational regime: latency divergence, classical-controller-limited runtime, or quantum-operation-limited runtime. Based on this understanding, we introduce latency-based benchmarks to set a standard for developing QEC control systems as the essential components of fault-tolerant quantum computation.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-14"},"PeriodicalIF":4.6,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11153908","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255938","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 squeezing plays a crucial role in enhancing the precision of quantum metrology and improving the efficiency of quantum information processing protocols. We thus propose a scheme to amplify two-mode squeezing in nanomechanical resonators, harnessing parametric amplification and two-tone laser controls. The red-detuned laser drives facilitate the cooling of the nanomechanical resonators down to their ground state and allow optimal quantum state transfer in the weak-coupling resolved sideband regime. In particular, the competing blue-detuned lasers in the driving pairs induce displacement squeezing in mechanical resonators. Thus, the quantum state transfer of squeezing in nanomechanical resonators and the intracavity correlated photons of the parametric amplifier significantly enhance two-mode mechanical squeezing. Notably, increasing the coupling strength of the red-detuned laser and the ratio of blue-to-red-detuned laser dramatically amplifies two-mode mechanical squeezing under realistic experimental parameters of a typical optomechanical system. Our findings reveal that the proposed cooperative mechanism effectively enhances the level of two-mode mechanical squeezing with a considerable improvement and demonstrates exceptional resilience to thermal noise.
{"title":"Amplifying Two-Mode Squeezing in Nanomechanical Resonators","authors":"Muhdin Abdo Wodedo;Tesfay Gebremariam Tesfahannes;Tewodros Yirgashewa Darge;Mauro Pereira;Berihu Teklu","doi":"10.1109/TQE.2025.3603459","DOIUrl":"https://doi.org/10.1109/TQE.2025.3603459","url":null,"abstract":"Quantum squeezing plays a crucial role in enhancing the precision of quantum metrology and improving the efficiency of quantum information processing protocols. We thus propose a scheme to amplify two-mode squeezing in nanomechanical resonators, harnessing parametric amplification and two-tone laser controls. The red-detuned laser drives facilitate the cooling of the nanomechanical resonators down to their ground state and allow optimal quantum state transfer in the weak-coupling resolved sideband regime. In particular, the competing blue-detuned lasers in the driving pairs induce displacement squeezing in mechanical resonators. Thus, the quantum state transfer of squeezing in nanomechanical resonators and the intracavity correlated photons of the parametric amplifier significantly enhance two-mode mechanical squeezing. Notably, increasing the coupling strength of the red-detuned laser and the ratio of blue-to-red-detuned laser dramatically amplifies two-mode mechanical squeezing under realistic experimental parameters of a typical optomechanical system. Our findings reveal that the proposed cooperative mechanism effectively enhances the level of two-mode mechanical squeezing with a considerable improvement and demonstrates exceptional resilience to thermal noise.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-15"},"PeriodicalIF":4.6,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11142662","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078581","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 : 2025-08-15DOI: 10.1109/TQE.2025.3599670
Xiangjun Tan;Zhanning Wang
Recent advances in quantum sensing and computational technologies indicate the possibility of improving the precision of measurements aimed at detecting cosmological particles and weakly interacting massive particles using various qubit platforms. While recent progress has been made, mitigating environmental noise remains a challenge in extracting particle parameters with high fidelity. Addressing these challenges requires efforts on two levels. At the device level, the qubit and its array acting as a probe must be isolated from electrical and magnetic noise through optimized device geometry. At the signal processing level, it is necessary to develop filtering methods targeting specific noise spectra based on different qubit architectures. In this work, we explore the possibility of using semiconductor quantum dot spin qubits as a platform to search for quantum chromodynamics (QCD) axions and, more broadly, axion-like particles. Starting by deriving an effective Hamiltonian for electron–axion interactions, we identify an axion-induced effective magnetic field and determine the characteristic axion oscillation frequency. To suppress charge noise in the devices and environmental noise, we first analyze the charge noise spectrum and then develop a dedicated filtering and noise-reduction protocol, paving the way for exploring feasible axion mass ranges. Our preliminary study holds promise for enhancing the screening of various axion signals using quantum technologies. We expect that our analysis and filtering protocol can help advance the use of semiconductor quantum dot spin qubit arrays in axion detection.
{"title":"Toward Axion Signal Extraction in Semiconductor Spin Qubits via Spectral Engineering","authors":"Xiangjun Tan;Zhanning Wang","doi":"10.1109/TQE.2025.3599670","DOIUrl":"https://doi.org/10.1109/TQE.2025.3599670","url":null,"abstract":"Recent advances in quantum sensing and computational technologies indicate the possibility of improving the precision of measurements aimed at detecting cosmological particles and weakly interacting massive particles using various qubit platforms. While recent progress has been made, mitigating environmental noise remains a challenge in extracting particle parameters with high fidelity. Addressing these challenges requires efforts on two levels. At the device level, the qubit and its array acting as a probe must be isolated from electrical and magnetic noise through optimized device geometry. At the signal processing level, it is necessary to develop filtering methods targeting specific noise spectra based on different qubit architectures. In this work, we explore the possibility of using semiconductor quantum dot spin qubits as a platform to search for quantum chromodynamics (QCD) axions and, more broadly, axion-like particles. Starting by deriving an effective Hamiltonian for electron–axion interactions, we identify an axion-induced effective magnetic field and determine the characteristic axion oscillation frequency. To suppress charge noise in the devices and environmental noise, we first analyze the charge noise spectrum and then develop a dedicated filtering and noise-reduction protocol, paving the way for exploring feasible axion mass ranges. Our preliminary study holds promise for enhancing the screening of various axion signals using quantum technologies. We expect that our analysis and filtering protocol can help advance the use of semiconductor quantum dot spin qubit arrays in axion detection.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-11"},"PeriodicalIF":4.6,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11127003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145036216","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 : 2025-08-06DOI: 10.1109/TQE.2025.3596392
Fabian Hader;Fabian Fuchs;Sarah Fleitmann;Karin Havemann;Benedikt Scherer;Jan Vogelbruch;Lotte Geck;Stefan van Waasen
Gate-defined semiconductor quantum dots require an appropriate number of electrons to function as qubits. The number of electrons is usually tuned by analyzing charge stability diagrams, in which charge transitions manifest as edges. Therefore, to fully automate qubit tuning, it is necessary to recognize these edges automatically and reliably. This article investigates possible detection methods, describes their training with simulated data from the SimCATS framework, and performs a quantitative comparison with a future hardware implementation in mind. Furthermore, we investigated the quality of the optimized approaches on experimentally measured data from a GaAs and a SiGe qubit sample.
{"title":"Automated Charge Transition Detection in Quantum Dot Charge Stability Diagrams","authors":"Fabian Hader;Fabian Fuchs;Sarah Fleitmann;Karin Havemann;Benedikt Scherer;Jan Vogelbruch;Lotte Geck;Stefan van Waasen","doi":"10.1109/TQE.2025.3596392","DOIUrl":"https://doi.org/10.1109/TQE.2025.3596392","url":null,"abstract":"Gate-defined semiconductor quantum dots require an appropriate number of electrons to function as qubits. The number of electrons is usually tuned by analyzing charge stability diagrams, in which charge transitions manifest as edges. Therefore, to fully automate qubit tuning, it is necessary to recognize these edges automatically and reliably. This article investigates possible detection methods, describes their training with simulated data from the SimCATS framework, and performs a quantitative comparison with a future hardware implementation in mind. Furthermore, we investigated the quality of the optimized approaches on experimentally measured data from a GaAs and a SiGe qubit sample.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-14"},"PeriodicalIF":4.6,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11119076","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021294","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 : 2025-08-06DOI: 10.1109/TQE.2025.3596491
Haley A. Weinstein;Bruno Avritzer;Christine M. Kinzfogl;Todd A. Brun;Jonathan L. Habif
Quantum steganography is a powerful method for information security where communication between a sender and receiver is disguised as naturally occurring noise in a channel. A candidate resource state required for implementing quantum steganography is a weak coherent state engineered with modulated phase and amplitude values drawn from probability distributions that result in a mixed state indistinguishable from a thermal state. We experimentally demonstrate the construction of this resource state by encoding the phase and amplitude of weak coherent laser states such that a third party monitoring the communication channel, measuring the flow of optical states through the channel, would see an amalgamation of states indistinguishable from thermal noise light such as that from spontaneous emission. Using quantum state tomography, we experimentally reconstructed the density matrices for the artificially engineered thermal states and spontaneous emission from an optical amplifier and verified a mean state fidelity $F=0.98$ when compared with theoretical thermal states.
{"title":"High-Fidelity Artificial Quantum Thermal State Generation Using Encoded Coherent States","authors":"Haley A. Weinstein;Bruno Avritzer;Christine M. Kinzfogl;Todd A. Brun;Jonathan L. Habif","doi":"10.1109/TQE.2025.3596491","DOIUrl":"https://doi.org/10.1109/TQE.2025.3596491","url":null,"abstract":"Quantum steganography is a powerful method for information security where communication between a sender and receiver is disguised as naturally occurring noise in a channel. A candidate resource state required for implementing quantum steganography is a weak coherent state engineered with modulated phase and amplitude values drawn from probability distributions that result in a mixed state indistinguishable from a thermal state. We experimentally demonstrate the construction of this resource state by encoding the phase and amplitude of weak coherent laser states such that a third party monitoring the communication channel, measuring the flow of optical states through the channel, would see an amalgamation of states indistinguishable from thermal noise light such as that from spontaneous emission. Using quantum state tomography, we experimentally reconstructed the density matrices for the artificially engineered thermal states and spontaneous emission from an optical amplifier and verified a mean state fidelity <inline-formula><tex-math>$F=0.98$</tex-math></inline-formula> when compared with theoretical thermal states.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-7"},"PeriodicalIF":4.6,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11118288","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145036671","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 : 2025-08-05DOI: 10.1109/TQE.2025.3595910
Shintaro Fujiwara;Naoki Ishikawa
This article presents a novel approach to Grover adaptive search (GAS) for a combinatorial optimization problem whose objective function involves spin variables. While the GAS algorithm with a conventional design of a quantum dictionary subroutine handles a problem associated with an objective function with binary variables $lbrace 0,1rbrace$, we reformulate the problem using spin variables $lbrace +1,-1rbrace$ to simplify the algorithm. Specifically, we introduce a novel quantum dictionary subroutine that is designed for this spin-based formulation. A key benefit of this approach is the substantial reduction in the number of cnot gates required to construct the quantum circuit. We theoretically demonstrate, for certain problems, that our proposed approach can reduce the gate complexity from an exponential order to a polynomial order, compared to the conventional binary-based approach. This improvement has the potential to enhance the scalability and efficiency of GAS, particularly in larger quantum computations.
{"title":"Grover Adaptive Search With Spin Variables","authors":"Shintaro Fujiwara;Naoki Ishikawa","doi":"10.1109/TQE.2025.3595910","DOIUrl":"https://doi.org/10.1109/TQE.2025.3595910","url":null,"abstract":"This article presents a novel approach to Grover adaptive search (GAS) for a combinatorial optimization problem whose objective function involves spin variables. While the GAS algorithm with a conventional design of a quantum dictionary subroutine handles a problem associated with an objective function with binary variables <inline-formula><tex-math>$lbrace 0,1rbrace$</tex-math></inline-formula>, we reformulate the problem using spin variables <inline-formula><tex-math>$lbrace +1,-1rbrace$</tex-math></inline-formula> to simplify the algorithm. Specifically, we introduce a novel quantum dictionary subroutine that is designed for this spin-based formulation. A key benefit of this approach is the substantial reduction in the number of <sc>cnot</small> gates required to construct the quantum circuit. We theoretically demonstrate, for certain problems, that our proposed approach can reduce the gate complexity from an exponential order to a polynomial order, compared to the conventional binary-based approach. This improvement has the potential to enhance the scalability and efficiency of GAS, particularly in larger quantum computations.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-13"},"PeriodicalIF":4.6,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11113358","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144990176","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 : 2025-08-04DOI: 10.1109/TQE.2025.3595778
Diogo Cruz;Francisco A. Monteiro;André Roque;Bruno C. Coutinho
This work addresses the open question of implementing fault-tolerant quantum random linear codes (QRLCs) with feasible computational overhead. We present a new decoder for QRLCs capable of dealing with imperfect decoding operations. A first approach, introduced by Cruz et al. (2023), only considered channel errors and perfect gates at the decoder. Here, we analyze the fault-tolerant characteristics of QRLCs with a new noise guessing decoding technique, when considering preparation, measurement, and gate errors in the syndrome extraction procedure, while also accounting for error degeneracy. Our findings indicate a threshold error rate (${p_{text{threshold}}}$) of approximately ${2times 10^{-5}}$ in the asymptotic limit, while considering realistic noise levels in the mentioned physical procedures.
{"title":"Fault-Tolerant Noise Guessing Decoding of Quantum Random Codes","authors":"Diogo Cruz;Francisco A. Monteiro;André Roque;Bruno C. Coutinho","doi":"10.1109/TQE.2025.3595778","DOIUrl":"https://doi.org/10.1109/TQE.2025.3595778","url":null,"abstract":"This work addresses the open question of implementing fault-tolerant quantum random linear codes (QRLCs) with feasible computational overhead. We present a new decoder for QRLCs capable of dealing with imperfect decoding operations. A first approach, introduced by Cruz et al. (2023), only considered channel errors and perfect gates at the decoder. Here, we analyze the fault-tolerant characteristics of QRLCs with a new noise guessing decoding technique, when considering preparation, measurement, and gate errors in the syndrome extraction procedure, while also accounting for error degeneracy. Our findings indicate a threshold error rate (<inline-formula><tex-math>${p_{text{threshold}}}$</tex-math></inline-formula>) of approximately <inline-formula><tex-math>${2times 10^{-5}}$</tex-math></inline-formula> in the asymptotic limit, while considering realistic noise levels in the mentioned physical procedures.","PeriodicalId":100644,"journal":{"name":"IEEE Transactions on Quantum Engineering","volume":"6 ","pages":"1-26"},"PeriodicalIF":4.6,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11112727","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934470","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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