Article
Quantum Science & Technology
Bo-Han Wu, Zheshen Zhang, Quntao Zhuang
Summary: This paper introduces a CV quantum-repeater architecture based on CV quantum teleportation, which is assisted by the Gottesman-Kitaev-Preskill code to suppress physical noise. The designed CV quantum-repeater architecture significantly improves the performance of entanglement-assisted communication, target detection based on quantum illumination, and CV quantum key distribution.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Optics
Daniel Alsina, Mohsen Razavi
Summary: The paper explores the relationship between AME states and QMDS codes by constructing QMDS codes from AME states with stabilizer representations. A reduction-friendly form for the generator set of stabilizer representation of an AME state is introduced, from which stabilizer form for children codes, all QMDS, can be obtained. The method is applicable to high-dimensional codes as well as qubit-based codes, and can be used to derive optimal QMDS codes for one-way quantum repeaters.
Article
Engineering, Electrical & Electronic
Daniel Nicolas Bailon, Martin Bossert, Johann-Philipp Thiers, Juergen Freudenberger
Summary: This work investigates concatenated codes based on the Plotkin construction, utilizing extended BCH codes as component codes. The proposed construction improves code parameters and allows for more flexible code rates compared to RM codes. New soft-input decoding algorithms are introduced, leveraging the recursive structure of the concatenation and cyclic structure of the component codes. The decoding algorithms achieve near-maximum-likelihood performance with reduced complexity.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2022)
Article
Quantum Science & Technology
Aurelie Denys, Anthony Leverrier
Summary: Quantum computers manipulate physical qubits encoded on two-level quantum systems, but bosonic qubit codes encode information in a well-chosen subspace of an infinite-dimensional Fock space, allowing them to circumvent certain limitations. This study introduces a two-mode generalization of the cat code, which lives in the span of 24 coherent states and demonstrates robustness in the low-loss regime. The properties of the binary tetrahedral group 2T are inherited by the resulting 2T-qutrit.
Article
Optics
Yousef K. Chahine, Ian R. Nemitz, John D. Lekki
Summary: This paper proposes a protocol to automatically identify and discard errors from stimulated multiphoton emissions by alternating the Bell state measurement basis in concatenated entanglement swapping links. It is shown that the protocol can completely eliminate the quadratic growth of multiphoton errors and enable more robust links in the presence of imbalanced channel losses. The analysis introduces a convenient calculus based on Clifford algebra for modeling concatenated entanglement swapping links with multiphoton emissions.
Article
Quantum Science & Technology
Paul Hilaire, Yaron Castor, Edwin Barnes, Sophia E. Economou, Frederic Grosshans
Summary: In this paper, we derive tight upper bounds for loss-tolerance thresholds in different linear-optical quantum information processing settings by considering the probabilistic nature of linear optical Bell measurements. We show analytically that linear optics can achieve the fundamental loss threshold imposed by the no-cloning theorem, which is less strict than the widely assumed constraint.
Article
Quantum Science & Technology
Hanwei Xiao, Xiaoguang Chen
Summary: This paper proposes a framework of quantum convolutional codes that can handle continuous errors, by concatenating GKP code and utilizing the output information of the decoding circuit through multiple iterations to further reduce errors.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Computer Science, Information Systems
Yingkai Ouyang, Earl T. Campbell
Summary: Quantum codes typically rely on large numbers of degrees of freedom for low error rates, but each additional degree introduces new error mechanisms. Utilizing fewer degrees of freedom can be helpful, one solution is encoding quantum information into bosonic modes. By using multiple modes, good approximate quantum error correction codes can be achieved for Gaussian dephasing and amplitude damping errors of any finite magnitude.
IEEE TRANSACTIONS ON INFORMATION THEORY
(2021)
Article
Computer Science, Hardware & Architecture
Johann-Philipp Thiers, Jurgen Freudenberger
Summary: Large-scale quantum computers pose a threat to the security of current public-key cryptography. The McEliece cryptosystem is a promising candidate for postquantum cryptography, but it has the drawback of large key sizes and high computational complexity. Hardware acceleration is required for efficient computation on resource-constrained devices. A proposed hardware decoder based on generalized concatenated codes shows that these systems are suitable for embedded devices.
IEEE CONSUMER ELECTRONICS MAGAZINE
(2023)
Article
Optics
Giacomo Pantaleoni, Ben Q. Baragiola, Nicolas C. Menicucci
Summary: The researchers utilize subsystem decomposition to analyze the encoded logical information in CV cluster-state quantum computing with GKP states. They decompose squeezed-vacuum states and approximate GKP states to reveal their logical information, and quantify damage to the logical information in approximate GKP states teleported through noisy CV cluster states. This approach allows them to focus on the encoded qubit information despite the complexities of the full CV nature of the mode.
Article
Physics, Multidisciplinary
Ji-Hao Fan, Jun Li, Han-Wu Chen, Wen-Jie Liu
Summary: In this work, new families of asymmetric quantum concatenated codes (AQCCs) are constructed to deal with biased quantum noise towards dephasing. The construction is based on a novel concatenation scheme utilizing classical tensor product codes and concatenated codes to correct phase flip noise and bit flip noise. The AQCCs designed in this paper show much better parameter performance compared to existing ones, and the specific encoding circuit of the AQCCs allows for more efficient encoding than standard quantum codes.
Article
Optics
Faezeh Kimiaee Asadi, Jia-Wei Ji, Christoph Simon
Summary: This study proposes a microwave-to-optical quantum transducer scheme based on rare-earth ions. By calculating and investigating, it shows that efficient conversion is possible at zero external magnetic fields.
Article
Engineering, Electrical & Electronic
Masoud Barakatain, Frank R. Kschischang
Summary: The proposed FEC scheme consists of an inner LDPC code and an outer zipper code, optimized for multiple transmission rates, channel qualities, and modulation orders with a focus on low estimated data-flow in decoding operation. A hardware-friendly quasi-cyclic structure is used for the inner code, achieving similar performance to existing FEC schemes with reduced decoding complexity by up to 63% or providing up to 0.6 dB coding gain at similar decoding complexity.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Mingyang Zhu, Ming Jiang, Chunming Zhao
Summary: This paper proposes a modified adaptive belief propagation (ABP) algorithm, called the random ABP (R-ABP) algorithm, for decoding short channel codes used in 5G NR wireless systems. By incorporating the cyclic redundancy check (CRC) bits into the iterative R-ABP decoding, the error correction performance can be improved while maintaining error detection capability through a proposed threshold-based acceptance criterion. The simulation results demonstrate that the proposed algorithm outperforms existing decoding algorithms for 5G LDPC and polar codes.
IEEE TRANSACTIONS ON COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Zhongchu Ni, Sai Li, Xiaowei Deng, Yanyan Cai, Libo Zhang, Weiting Wang, Zhen-Biao Yang, Haifeng Yu, Fei Yan, Song Liu, Chang-Ling Zou, Luyan Sun, Shi-Biao Zheng, Yuan Xu, Dapeng Yu
Summary: Quantum error correction (QEC) protects logical qubits by using a large Hilbert space with redundancy to detect and correct errors in real time. In this study, a QEC procedure was demonstrated in a circuit quantum electrodynamics architecture, where a logical qubit was encoded in photon-number states of a microwave cavity and coupled to an auxiliary superconducting qubit. By applying a tailored frequency comb pulse, error syndrome was extracted and error correction was performed, exceeding the break-even point by about 16% lifetime enhancement. This work illustrates the potential of hardware-efficient discrete-variable encodings for fault-tolerant quantum computation.
Article
Physics, Multidisciplinary
Hyukgun Kwon, Youngrong Lim, Liang Jiang, Hyunseok Jeong, Changhun Oh
Summary: The quantum metrological power of typical continuous-variable quantum networks is investigated in this study. It is shown that these networks can enable Heisenberg scaling in the number of modes for distributed quantum displacement sensing by providing entanglement to quantum states in distant nodes. The quantum enhancement can be achieved using local operations and measurements.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Changhun Oh, Youngrong Lim, Bill Fefferman, Liang Jiang
Summary: This letter introduces classical sampling algorithms for single-photon and Gaussian input states using the graph structure of a linear-optical circuit. The complexity of the algorithms is closely related to the connectivity of the linear-optical circuit. The study shows that efficient simulation is possible for local Haar-random linear-optical circuits when the circuit depth is less than the quadratic in the lattice spacing.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Harald Putterman, Joseph Iverson, Qian Xu, Liang Jiang, Oskar Painter, Fernando G. S. L. Brandao, Kyungjoo Noh
Summary: This article introduces a scheme for stabilizing energy-gap-protected qubits using colored dissipation, specifically focusing on Kerr-cat qubits. This technique effectively suppresses leakage-induced bit-flip errors and improves the performance of quantum bits.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Qian Xu, Alireza Seif, Haoxiong Yan, Nam Mannucci, Bernard Ousmane Sane, Rodney Van Meter, Andrew N. Cleland, Liang Jiang
Summary: Quantum error correction is crucial for scaling up quantum computers. In this study, a distributed error correction scheme is proposed to combat the devastating impact of cosmic ray events on quantum computers. The scheme introduces an additional layer of quantum erasure error correcting code across separate chips and has shown fault tolerant behavior against chip-level catastrophic errors. Experimental implementation using superconducting qubits with microwave links has been discussed, and the analysis suggests that the error rate can be suppressed from 1 per 10 s to less than 1 per month.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Qian Xu, Nam Mannucci, Alireza Seif, Aleksander Kubica, Steven T. Flammia, Liang Jiang
Summary: Quantum error correction (QEC) for generic errors is challenging, but when physical noise is biased, tailored QEC schemes can improve performance. In this study, we explored XZZX codes that are highly efficient if tailored to biased noise. By using the notion of effective distance, we found that the XZZX codes achieve favorable resource scaling and remarkably high thresholds, while also being efficiently decoded. Additionally, these codes can realize fault-tolerant QEC with a large effective distance by adding only one flag qubit.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Optics
Guus Avis, Filip Rozpedek, Stephanie Wehner
Summary: We study the performance of distributing multipartite entangled states in a quantum network through a central node. We provide analytical expressions and lower bounds for the rate and fidelity of distributing Greenberger-Horne-Zeilinger (GHZ) states through quantum teleportation. We also compare the performance to a distributed scenario where the GHZ state is created by the end nodes.
Article
Physics, Multidisciplinary
Changhun Oh, Liang Jiang, Changhyoup Lee
Summary: In this work, a Heisenberg-limited distributed quantum phase sensing scheme using Gaussian states for an arbitrary distribution of weights is proposed. The scheme exploits entanglement of Gaussian states only among the modes assigned with equal signs of the weights. The estimation precision of the scheme exhibits Heisenberg scaling in the mean photon number and it is proven to be optimal for Gaussian probe states with zero displacement.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
Tanay Roy, Liang Jiang, David Schuster
Summary: Grover's quantum search algorithm provides a quadratic quantum advantage over classical algorithms for unstructured search problems. We present a modified version that returns the correct result with certainty without user control over the quantum search oracle. The visualization using the Bloch sphere enhances geometric intuition.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
Wen-Long Ma, Shu-Shen Li, Liang Jiang
Summary: This research reveals the algebraic structure of path-independent quantum control and provides an exact and unified condition for combating ancilla noise.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Kaushik P. Seshadreesan, Prajit Dhara, Ashlesha Patil, Liang Jiang, Saikat Guha
Summary: This study focuses on the generation of high-fidelity graph states composed of realistic, finite-energy approximate GKP-encoded qubits in the photonic qubit architecture. The researchers track the transformation of the graph states under GKP-Steane error-correction and fusion operations using standard Gaussian dynamics, and provide an exact coherent error model to shed light on the error-correction properties of these graph states.
Article
Optics
Senrui Chen, Sisi Zhou, Alireza Seif, Liang Jiang
Summary: We demonstrate that entangled measurements provide an exponential advantage in sample complexity for Pauli channel estimation, which is a fundamental problem and a necessary subroutine for benchmarking near-term quantum devices. Through our research, we provide an estimation protocol using ancilla that significantly reduces the number of copies of the Pauli channel required for accurate estimation. We also explore the benefits of a limited number of ancillas and how to apply the estimation protocol to practical quantum benchmarking tasks.
Article
Quantum Science & Technology
Christopher Chamberland, Kyungjoo Noh, Patricio Arrangoiz-Arriola, Earl T. Campbell, Connor T. Hann, Joseph Iverson, Harald Putterman, Thomas C. Bohdanowicz, Steven T. Flammia, Andrew Keller, Gil Refael, John Preskill, Liang Jiang, Amir H. Safavi-Naeini, Oskar Painter, Fernando G. S. L. Brandao
Summary: This paper presents a comprehensive architectural analysis for a fault-tolerant quantum computer based on cat codes combined with outer quantum error-correcting codes. The hardware proposed is a system of acoustic resonators coupled to superconducting circuits with a two-dimensional layout. Through detailed error analysis and numerical simulations, realistic estimates of the physical error rates and overheads needed to run fault-tolerant quantum algorithms are obtained. The study finds that with around 1000 superconducting circuit components, it is possible to construct a fault-tolerant quantum computer capable of running circuits currently intractable for classical computers.
Article
Quantum Science & Technology
Kyungjoo Noh, Christopher Chamberland, Fernando G. S. L. Brandao
Summary: In this work, we propose a highly effective use of the surface Gottesman-Kitaev-Preskill (GKP) code, which reduces the total failure rate and achieves a low logical failure rate. By combining GKP code with the surface code, the threshold GKP squeezing is determined under the assumption of dominant noise source. The use of space-time correlated edges and dynamically computed edge weights in the matching graphs enables the realization of highly squeezed GKP states with conservative experimental parameters.
Article
Physics, Multidisciplinary
Qian Xu, Joseph K. Iverson, Fernando G. S. L. Brandao, Liang Jiang
Summary: This paper explores the method of implementing fast biased gates on stabilized cat codes. By applying a leakage-suppression technique, the nonadiabatic errors are overcome, resulting in improved gate fidelity. Applying this method in concatenated quantum error correction can improve the logical error rate and reduce resource overhead, enabling more efficient implementation of fault-tolerant quantum computing.
PHYSICAL REVIEW RESEARCH
(2022)
