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Exploration of Optimizing FPGA-based Qubit Controller for Experiments on Superconducting quantum computing Hardware

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Exploration of Optimizing FPGA-based Qubit Controller for Ex...

IEEE International Conference on Electro-Information technology

作者： Hans Johnson Silvia Zorzetti Jafar Saniie Department of Electrical and Computer Engineering Embedded Computing and Signal Processing (ECASP) Research Laboratory Illinois Institute of Technology Chicago IL U.S.A. Superconducting Quantum Materials and Systems Center (SQMS) Fermi National Accelerator Laboratory Batavia IL U.S.A.

This work explores avenues and target areas for optimizing FPGA-based control hardware for experiments conducted on superconducting quantum computing systems and serves as an introduction to some of the current research at the intersection of classical and quantum computing hardware. With the promise of building larger-scale error-corrected quantum computers based on superconducting qubit architecture, innovations to room-temperature control electronics are needed to bring these quantum realizations to fruition. The QICK (quantum Instrumentation Control Kit) is one leading experimental FPGA-based implementations. However, its integration into other experimental quantum computing architectures, especially those using superconducting radiofrequency (SRF) cavities, is largely unexplored. We identify some key target areas for optimizing control electronics for superconducting qubit architectures and provide some preliminary results to the resolution of a control pulse waveform. With optimizations targeted at 3D superconducting qubit setups, we hope to bring to light some of the requirements in classical computational methodologies to bring out the full potential of this quantum computing architecture, and to convey the excitement of progress in this research.

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Optimization by Decoded quantum Interferometry

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arXiv 2024年

作者： Jordan, Stephen P. Shutty, Noah Wootters, Mary Zalcman, Adam Schmidhuber, Alexander King, Robbie Isakov, Sergei V. Babbush, Ryan Google Quantum AI VeniceCA90291 United States Departments of Computer Science and Electrical Engineering Stanford University StanfordCA94305 United States Center for Theoretical Physics Massachusetts Institute of Technology CambridgeMA02139 United States Department of Computing and Mathematical Sciences Caltech PasadenaCA91125 United States

Whether quantum computers can achieve exponential speedups in optimization has been a major open question in quantum algorithms since the field began. Here we introduce a quantum algorithm called Decoded quantum Interferometry (DQI), which uses the quantum Fourier transform to reduce optimization problems to decoding problems. For approximating optimal polynomial fits to data over finite fields, DQI efficiently achieves a better approximation ratio than any polynomial time classical algorithm known to us, thus suggesting exponential quantum speedup. We also extend this to multivariate polynomials. These optimization problems are solved approximately by quantum reduction to decoding of Reed-Solomon and Reed-Muller codes, respectively. Sparse unstructured optimization problems such as max-k-XORSAT are reduced to decoding of LDPC codes. Although we have not identified quantum advantage for the sparse unstructured case, we prove a theorem which allows the performance of DQI to be calculated instance-by-instance based on the empirical performance of classical LDPC decoders such as belief propagation. We demonstrate this by benchmarking on an instance with over 30,000 variables. Copyright © 2024, The Authors. All rights reserved.

关键词： Reed-Solomon codes

Emergent quantum Mechanics at the Boundary of a Local Classical Lattice Model

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arXiv 2022年

作者： Slagle, Kevin Preskill, John Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Department of Physics California Institute of Technology PasadenaCA91125 United States Institute for Quantum Information and Matter Walter Burke Institute for Theoretical Physics California Institute of Technology PasadenaCA91125 United States AWS Center for Quantum Computing PasadenaCA91125 United States

We formulate a conceptually new model in which quantum mechanics emerges from classical mechanics. Given a local Hamiltonian H acting on n qubits, we define a local classical model with an additional spatial dimension whose boundary dynamics is approximately—but to arbitrary precision—described by Schrödinger’s equation and H. The bulk consists of a lattice of classical bits that propagate towards the boundary through a circuit of stochastic matrices. The bits reaching the boundary are governed by a probability distribution whose deviation from the uniform distribution can be interpreted as the quantum-mechanical wavefunction. Bell nonlocality is achieved because information can move through the bulk much faster than the boundary speed of light. We analytically estimate how much the model deviates from quantum mechanics, and we validate these estimates using computer simulations. Copyright © 2022, The Authors. All rights reserved.

关键词： quantum theory

Spin and Orbital Moments of Magnetic Topological Insulator MnBi2Te4 Epitaxial Thin Films

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Spin and Orbital Moments of Magnetic Topological Insulator M...

Magnetic Conference - Short Papers (INTERMAG Short Papers), IEEE International

作者： Jiabao Sun Shanshan Liu Faxian Xiu Wenqing Liu Department of Electronic Engineering Royal Holloway University of London Egham United Kingdom Beijing Superstring Academy of Memory Technology Beijing China Department of Physics State Key Laboratory of Surface Physics Fudan University Shanghai China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai China Department of Electrical Engineering and Electronics University of Liverpool Liverpool United Kingdom

ISBN: (数字)9798350362213

ISBN: (纸本)9798350362220

Intrinsic magnetic topological insulators (MTIs) have proven to be an important material system for the study of quantum effects and the development of novel electronic devices. Unlike the magnetically doped topological insulators (TIs)., intrinsic MTIs well preserve the crystalline ordering and homogeneity of the pristine TIs, leading to enhanced quantum coherency in many cases. Here, we report a detailed study of the atomic scale spin $(m_{\mathrm{s}})$ and orbital $(m1)$ moments of an epitaxial $\text{MnBi}_{2}\text{Te}\triangleleft$ thin film. The synchrotron-based x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements were performed to investigate the electronic and magnetic properties of the thin film at 3 K and up to 14 T. The 16.3 nm $\text{MnBi}_{2}\text{Te}4/\mathrm{A}1_{2}\mathrm{O}_{2}$ shows reduced moments of $m_{\mathrm{s}}= (1.64\pm 0.2)\mu_{\mathrm{B}}/\text{Mn}$ and $m1=(0.16\pm 0.02)\mu_{\mathrm{B}}/\text{Mn}$ at 14 T compared to their bulk counterparts. The reduced magnetic moments may be attributed to the weakened intralayer or interlayer exchange interaction and the intrinsic structural defects of the materials. Future work to understand the correlations between the structural defects, intralayer or interlayer exchange interactions, and magnetic properties will have strong implications for both fundamental physics and practical applications of the $\text{MnBi}_{2}\text{Te}_{4}$ materials.

关键词： Magnetic films Elementary particle exchange interactions Spectroscopy Molecular beam epitaxial growth Magnetic devices Magnetic moments Orbits

Distinguishability-based genuine nonlocality with genuine multipartite entanglement

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arXiv 2022年

作者： Xiong, Zong-Xing Li, Mao-Sheng Zheng, Zhu-Jun Li, Lvzhou Institute of Quantum Computing and Computer Theory School of Computer Science and Engineering Sun Yat-Sen University Guangzhou510006 China School of Mathematics South China University of Technology Guangzhou510640 China

A set of orthogonal multipartite quantum states is said to be distinguishability-based genuinely nonlocal (also genuinely nonlocal, for abbreviation) if the states are locally indistinguishable across any bipartition of the subsystems. This form of multipartite nonlocality, although more naturally arising than the recently popular "strong nonlocality" in the context of local distinguishability, receives much less attention. In this work, we study the distinguishability-based genuine nonlocality of a typical type of genuine multipartite entangled states — the d-dimensional GHZ states, featuring systems with local dimension not limited to 2. In the three-partite case, we find the existence of small genuinely nonlocal sets consisting of these states: we show that the cardinality can at least scale down to linear in the local dimension d, with the linear factor l = 1. Specifically, the method we use is semidefinite program and the GHZ states to construct these sets are special ones which we call "GHZ-lattices". This result might arguably suggest a significant gap between the strength of strong nonlocality and the distinguishability-based genuine nonlocality. Moreover, we put forward the notion of (s, n)-threshold distinguishability and utilizing a similar method, we successfully construct (2, 3)-threshold sets consisting of GHZ states in three-partite systems. © 2022, CC BY.

关键词： quantum entanglement

Improving Signal-to-Noise Ratio (SNR) for Readout Signals Using Adaptive Filters on Reconfigurable Controls Hardware

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Improving Signal-to-Noise Ratio (SNR) for Readout Signals Us...

quantum computing and engineering (QCE), IEEE International Conference on

作者： Hans Johnson Silvia Zorzetti Jafar Saniie Department of Electrical and Computer Engineering Embedded Computing and Signal Processing (ECASP) Research Laboratory Illinois Institute of Technology Chicago IL U.S.A. Fermi National Accelerator Laboratory Superconducting Quantum Materials and Systems Center (SQMS) Batavia IL U.S.A.

This study investigates the optimization of Signal-to-Noise Ratio (SNR) in superconducting quantum computing readout signals through adaptive filtering. quantum computing technology has the potential to revolutionize various fields by delivering exponential speedup in solving certain computational problems. However, the technology's practical implementation is hindered by the difficulty of extracting clean, reliable signals during the readout phase, with various sources of noise presenting a significant barrier to clean signals. This noise, often present in readout profiles due to imperfect isolation, degrades the system's overall SNR, thus impeding the ability to extract the quantum state accurately. The research leverages the power of adaptive filtering to improve the SNR of quantum computing readout signals. Specifically, an adaptive filter is implemented in a PYNQ overlay on an FPGA, and eventually will be connected to a quantum computing system. The system models the noise with a Least Mean Squares (LMS) adaptive filter, and then subtracts the estimated noise from the received signal to improve the SNR. A Direct Memory Access (DMA) channel is used to handle the signal processing, delivering efficient, high-speed data transfer between the PYNQ system and the hardware. The study explores the benefits of this adaptive filtering technique, potentially providing a significant contribution to practical and fast quantum computing.

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Hardware-efficient quantum error correction via concatenated bosonic qubits

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arXiv 2024年

作者： Putterman, Harald Noh, Kyungjoo Hann, Connor T. MacCabe, Gregory S. Aghaeimeibodi, Shahriar Patel, Rishi N. Lee, Menyoung Jones, William M. Moradinejad, Hesam Rodriguez, Roberto Mahuli, Neha Rose, Jefferson Owens, John Clai Levine, Harry Rosenfeld, Emma Reinhold, Philip Moncelsi, Lorenzo Alcid, Joshua Ari Alidoust, Nasser Arrangoiz-Arriola, Patricio Barnett, James Bienias, Przemyslaw Carson, Hugh A. Chen, Cliff Chen, Li Chinkezian, Harutiun Chisholm, Eric M. Chou, Ming-Han Clerk, Aashish Clifford, Andrew Cosmic, R. Curiel, Ana Valdes Davis, Erik DeLorenzo, Laura Mitchell D’Ewart, J. Diky, Art D’Souza, Nathan Dumitrescu, Philipp T. Eisenmann, Shmuel Elkhouly, Essam Evenbly, Glen Fang, Michael T. Fang, Yawen Fling, Matthew J. Fon, Warren Garcia, Gabriel Gorshkov, Alexey V. Grant, Julia A. Gray, Mason J. Grimberg, Sebastian Grimsmo, Arne L. Haim, Arbel Hand, Justin He, Yuan Hernandez, Mike Hover, David Hung, Jimmy S.C. Hunt, Matthew Iverson, Joe Jarrige, Ignace Jaskula, Jean-Christophe Jiang, Liang Kalaee, Mahmoud Karabalin, Rassul Karalekas, Peter J. Keller, Andrew J. Khalajhedayati, Amirhossein Kubica, Aleksander Lee, Hanho Leroux, Catherine Lieu, Simon Ly, Victor Madrigal, Keven Villegas Marcaud, Guillaume McCabe, Gavin Miles, Cody Milsted, Ashley Minguzzi, Joaquin Mishra, Anurag Mukherjee, Biswaroop Naghiloo, Mahdi Oblepias, Eric Ortuno, Gerson Pagdilao, Jason Pancotti, Nicola Panduro, Ashley Paquette, J.P. Park, Minje Peairs, Gregory A. Perello, David Peterson, Eric C. Ponte, Sophia Preskill, John Qiao, Johnson Refael, Gil Resnick, Rachel Retzker, Alex Reyna, Omar A. Runyan, Marc Ryan, Colm A. Sahmoud, Abdulrahman Sanchez, Ernesto Sanil, Rohan Sankar, Krishanu Sato, Yuki Scaffidi, Thomas Siavoshi, Salome Sivarajah, Prasahnt Skogland, Trenton Su, Chun-Ju Swenson, Loren J. Teo, Stephanie M. Tomada, Astrid Torlai, Giacomo Alex Wollack, E. Ye, Yufeng Zerrudo, Jessica A. Zhang, Kailing Brandão, Fernando G.S.L. Matheny, Matthew H. Painter, Oskar AWS Center for Quantum Computing PasadenaCA91125 United States Pritzker School of Molecular Engineering The University of Chicago IL60637 United States IQIM California Institute of Technology PasadenaCA91125 United States Racah Institute of Physics The Hebrew University of Jerusalem Givat Ram Jerusalem91904 Israel Thomas J. Watson Sr. Laboratory of Applied Physics California Institute of Technology PasadenaCA91125 United States

In order to solve problems of practical importance [1, 2], quantum computers will likely need to incorporate quantum error correction, where a logical qubit is redundantly encoded in many noisy physical qubits [3–5]. The large physical-qubit overhead typically associated with error correction motivates the search for more hardware-efficient approaches [6–18]. Here, using a microfabricated superconducting quantum circuit [19, 20], we realize a logical qubit memory formed from the concatenation of encoded bosonic cat qubits with an outer repetition code of distance d = 5 [10]. The bosonic cat qubits are passively protected against bit flips using a stabilizing circuit [21–25]. Cat-qubit phase-flip errors are corrected by the repetition code which uses ancilla transmons for syndrome measurement. We realize a noise-biased CX gate which ensures bit-flip error suppression is maintained during error correction. We study the performance and scaling of the logical qubit memory, finding that the phase-flip correcting repetition code operates below threshold, with logical phase-flip error decreasing with code distance from d = 3 to d = 5. Concurrently, the logical bit-flip error is suppressed with increasing cat-qubit mean photon number. The minimum measured logical error per cycle is on average 1.75(2)% for the distance-3 code sections, and 1.65(3)% for the longer distance-5 code, demonstrating the effectiveness of bit-flip error suppression throughout the error correction cycle. These results, where the intrinsic error suppression of the bosonic encodings allows us to use a hardware-efficient outer error correcting code, indicate that concatenated bosonic codes are a compelling paradigm for reaching fault-tolerant quantum computation. Copyright © 2024, The Authors. All rights reserved.

关键词： Qubits

Maximal coin-walker entanglement in a ballistic quantum walk

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Physical Review A 2022年第4期105卷 042216-042216页

作者： Rong Zhang Ran Yang Jian Guo Chang-Wei Sun Jia-Chen Duan Heng Zhou Zhenda Xie Ping Xu Yan-Xiao Gong Shi-Ning Zhu National Laboratory of Solid State Microstructure School of Physics School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China College of Electronic and Optical Engineering Nanjing University of Posts and Telecommunication Nanjing 210023 China School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu 611731 China Institute for Quantum Information and State Key Laboratory of High Performance Computing College of Computing National University of Defense Technology Changsha 410073 China

We report that the position-inhomogeneous quantum walk (IQW) can be utilized to produce the maximal high-dimensional entanglement while maintaining the quadratic speedup spread of the wave function. Our calculations show that the maximal coin-walker entanglement can be generated in any odd steps or asymptotically in even steps, and the nearly maximal entanglement can be obtained in even steps after 2. We implement the IQW by a stable resource-saving time-bin optical network, in which a polarization Sagnac loop is employed to realize the precisely tunable phase shift. Our approach opens up an efficient way for high-dimensional entanglement engineering as well as promotes investigations on the role of coin-walker interactions in QW-based applications.

关键词： Entanglement manipulation Optical quantum information processing quantum optics quantum walks

Partial Equivalence Checking of quantum Circuits

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arXiv 2022年

作者： Chen, Tian-Fu Jiang, Jie-Hong R. Hsieh, Min-Hsiu Department of Electrical Engineering National Taiwan University Taipei Taiwan Graduate School of Advanced Technology National Taiwan University Taipei Taiwan Center for Quantum Science and Engineering National Taiwan University Taipei Taiwan Graduate Institute of Electronics Engineering National Taiwan University Taipei Taiwan Quantum Computing Research Center Hon Hai Research Institute Taipei Taiwan

Equivalence checking of quantum circuits is an essential element in quantum program compilation, in which a quantum program can be synthesized into different quantum circuits that may vary in the number of qubits, initialization requirements, and output states. Verifying the equivalences among the implementation variants requires proper generality. Although different notions of quantum circuit equivalence have been defined, prior methods cannot check observational equivalence between two quantum circuits whose qubits are partially initialized, which is referred to as partial equivalence. In this work, we prove a necessary and sufficient condition for two circuits to be partially equivalent. Based on the condition, we devise algorithms for checking quantum circuits whose partial equivalence cannot be verified by prior approaches. Experiment results confirm the generality and demonstrate the efficiency and effectiveness of our method. Our result may unleash the optimization power of quantum program compilation to take more aggressive steps. © 2022, CC BY-NC-ND.

关键词： Qubits