Article
Physics, Applied
C. R. Conner, A. Bienfait, H. -S. Chang, M. -H. Chou, E. Dumur, J. Grebel, G. A. Peairs, R. G. Povey, H. Yan, Y. P. Zhong, A. N. Cleland
Summary: A simple and inexpensive method is demonstrated to reliably couple superconducting qubit circuits without the need for a galvanic connection, allowing for full vector qubit control and high-fidelity single-shot readout on each qubit on separate dies. The method further enables entanglement-generating excitation swaps and benchmarking of a controlled-Z entangling gate between qubits on different dies. This assembly approach supports the integration of two-plus-one-dimensional quantum circuits using delicate or unusually shaped substrates.
APPLIED PHYSICS LETTERS
(2021)
Editorial Material
Physics, Multidisciplinary
Stuart J. Masson, Ana Asenjo-Garcia
Summary: Photon emission, which causes the decoherence in various quantum technologies, has been significantly suppressed by combining four superconducting qubits to create a 'dark state' qubit with collective interference effects.
Editorial Material
Chemistry, Physical
Christian Schonenberger
Summary: The exceptional quality of hexagonal boron nitride crystals allows for the creation of ultrathin dielectrics, enabling the development of ultrasmall capacitors with large capacitances. By utilizing these capacitors, the superconducting transmon qubit can be scaled down by orders of magnitude.
Review
Nanoscience & Nanotechnology
Irfan Siddiqi
Summary: The review explores the major sources of decoherence in superconducting qubits and the trade-offs between simple and complex circuit designs. It also discusses the impact of materials optimization strategies on quantum computing.
NATURE REVIEWS MATERIALS
(2021)
Review
Materials Science, Multidisciplinary
Conal E. Murray
Summary: The progress in quantum computing is driven by understanding qubit-state interactions with the environment, focusing on superconducting qubits and their mechanisms for relaxation and decoherence. Experimental techniques for assessing these mechanisms are highlighted, emphasizing the significance of dielectric loss and interactions with two-level systems. Future research should prioritize mitigating these effects for successful scaling of superconducting quantum computing.
MATERIALS SCIENCE & ENGINEERING R-REPORTS
(2021)
Article
Quantum Science & Technology
J. H. Bejanin, C. T. Earnest, Y. R. Sanders, M. Mariantoni
Summary: This paper demonstrates a method to efficiently learn the parameters of resonant interactions in quantum computers, utilizing offline data collection and online Bayesian learning algorithms to significantly reduce calibration time. This technique has the potential to improve the performance of current medium-scale superconducting quantum computers and scale up to larger systems, making it accessible to different physical implementations of quantum computing architectures.
Article
Quantum Science & Technology
Giampiero Marchegiani, Luigi Amico, Gianluigi Catelani
Summary: Designing the spatial profile of the superconducting gap, known as gap engineering, is an effective way to control quasiparticles in superconducting devices. In this study, the quasiparticle effects in superconducting qubits are reconsidered to account for the inevitable asymmetry in the gap on the two sides of a Josephson junction. Different regimes are found, where quasiparticles have either similar densities in the two junction leads or are largely confined to one side with lower gap. The qubit's excited-state population is lower but its relaxation rate is higher when the quasiparticles are confined, indicating a potential trade-off between two desirable properties in a qubit.
Article
Quantum Science & Technology
Kaixuan Huang, Zheng-An Wang, Chao Song, Kai Xu, Hekang Li, Zhen Wang, Qiujiang Guo, Zixuan Song, Zhi-Bo Liu, Dongning Zheng, Dong-Ling Deng, H. Wang, Jian-Guo Tian, Heng Fan
Summary: Generative adversarial networks have been successful in machine learning, and their quantum counterparts, known as quantum generative adversarial networks (QGANs), may have exponential advantages. Researchers have implemented a QGAN using a programmable superconducting processor, paving the way for experimental explorations of quantum advantages in practical applications with near-term quantum technologies.
NPJ QUANTUM INFORMATION
(2021)
Article
Physics, Multidisciplinary
Chong Ying, Bin Cheng, Youwei Zhao, He-Liang Huang, Yu-Ning Zhang, Ming Gong, Yulin Wu, Shiyu Wang, Futian Liang, Jin Lin, Yu Xu, Hui Deng, Hao Rong, Cheng-Zhi Peng, Man -Hong Yung, Xiaobo Zhu, Jian-Wei Pan
Summary: Although NISQ quantum computing devices are still limited in terms of qubit quantity and quality, quantum computational advantage has been experimentally demonstrated. Hybrid quantum and classical computing architectures have become the main paradigm for exhibiting NISQ applications, with the use of low-depth quantum circuits. This study demonstrates a circuit-cutting method for simulating quantum circuits with multiple logical qubits using only a few physical superconducting qubits, showcasing higher fidelity and scalability.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Youwei Zhao, Yangsen Ye, He-Liang Huang, Yiming Zhang, Dachao Wu, Huijie Guan, Qingling Zhu, Zuolin Wei, Tan He, Sirui Cao, Fusheng Chen, Tung-Hsun Chung, Hui Deng, Daojin Fan, Ming Gong, Cheng Guo, Shaojun Guo, Lianchen Han, Na Li, Shaowei Li, Yuan Li, Futian Liang, Jin Lin, Haoran Qian, Hao Rong, Hong Su, Lihua Sun, Shiyu Wang, Yulin Wu, Yu Xu, Chong Ying, Jiale Yu, Chen Zha, Kaili Zhang, Yong-Heng Huo, Chao-Yang Lu, Cheng-Zhi Peng, Xiaobo Zhu, Jian-Wei Pan
Summary: This article describes an experimental implementation of an error-correcting surface code on a superconducting quantum processor. By executing multiple consecutive error correction cycles, logical errors were significantly reduced, providing a key step towards scalable fault-tolerant quantum computing.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Maria Spethmann, Xian-Peng Zhang, Jelena Klinovaja, Daniel Loss
Summary: Superconducting spin qubits, coupled to each other via a superconductor, demonstrate fast controlled phase-flip gates. The effective interaction between these qubits can be adjusted by the superconducting phase difference, the tunnel barrier strength, or the spin-orbit interaction parameters.
Article
Physics, Applied
Sergey Bravyi, Oliver Dial, Jay M. Gambetta, Dario Gil, Zaira Nazario
Summary: With the emergence of quantum processing units (QPUs), we are witnessing a branching point in computing paradigms. Advancements in quantum error correction technology are necessary to fully exploit the potential of quantum computing. In the short term, combining multiple QPUs and improving solution quality through error suppression and heuristic versions of quantum algorithms may lead to computational advantages. Quantum-centric supercomputing, which integrates quantum and classical processors seamlessly, is the future architecture. In the long term, hardware with higher dimensional qubit connectivity and software that evolves to hide the complexities of the technology are envisioned.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Quantum Science & Technology
Alexandre M. Souza
Summary: In this study, dynamical decoupling sequences were tested on a single qubit using the Rigetti quantum computing platform. It was found that pulse imperfections limited the performance, but using robust sequences improved the effectiveness of dynamical decoupling. The tested sequences outperformed previous ones on the same platform.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Optics
Ciro Micheletti Diniz, Rogerio Jorge de Assis, Norton G. de Almeida, Celso J. Villas-Boas
Summary: This study performs a detailed analysis of information resetting in superconducting qubits and explores three different models. It is found that simply increasing the coupling and dissipation rate of the auxiliary systems does not reduce the reset time of the main qubit. The researchers identified the optimal parameter combinations for each model, resulting in a significant decrease in reset time for the three analyzed models.
Article
Quantum Science & Technology
Andrea Maiani, Morten Kjaergaard, Constantin Schrade
Summary: This study proposes and investigates a scheme for entangling a tunable transmon with a Cooper-pair parity-protected qubit. By tuning the external flux on the transmon, a two-qubit entangling gate that is independent of the specific pulse sequence can be achieved. This scheme has the potential to facilitate the operation of heterogeneous quantum processors.
Article
Multidisciplinary Sciences
Youpeng Zhong, Hung-Shen Chang, Audrey Bienfait, Etienne Dumur, Ming-Han Chou, Christopher R. Conner, Joel Grebel, Rhys G. Povey, Haoxiong Yan, David Schuster, Andrew N. Cleland
Summary: High-fidelity deterministic quantum state transfer and multi-qubit entanglement were demonstrated in a quantum network consisting of two superconducting quantum nodes connected by a one-meter-long superconducting coaxial cable. This work successfully achieved the deterministic generation and transmission of multi-qubit entanglement with high state fidelities, showing the potential for building large-scale quantum computers through modular linking of superconducting quantum processors.
Article
Physics, Multidisciplinary
Haoxiong Yan, Youpeng Zhong, Hung-Shen Chang, Audrey Bienfait, Ming-Han Chou, Christopher R. Conner, Etienne Dumur, Joel Grebel, Rhys G. Povey, Andrew N. Cleland
Summary: This research demonstrates the entanglement purification of Bell pairs shared between two remote superconducting quantum nodes through a purification process to correct amplitude damping errors, increasing fidelity. Additionally, dynamical decoupling and Rabi driving are used to protect entangled states from local noise, enhancing qubit dephasing time.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
K. J. Satzinger, Y-J Liu, A. Smith, C. Knapp, M. Newman, C. Jones, Z. Chen, C. Quintana, X. Mi, A. Dunsworth, C. Gidney, I Aleiner, F. Arute, K. Arya, J. Atalaya, R. Babbush, J. C. Bardin, R. Barends, J. Basso, A. Bengtsson, A. Bilmes, M. Broughton, B. B. Buckley, D. A. Buell, B. Burkett, N. Bushnell, B. Chiaro, R. Collins, W. Courtney, S. Demura, A. R. Derk, D. Eppens, C. Erickson, L. Faoro, E. Farhi, A. G. Fowler, B. Foxen, M. Giustina, A. Greene, J. A. Gross, M. P. Harrigan, S. D. Harrington, J. Hilton, S. Hong, T. Huang, W. J. Huggins, L. B. Ioffe, S. Isakov, E. Jeffrey, Z. Jiang, D. Kafri, K. Kechedzhi, T. Khattar, S. Kim, P. Klimov, A. N. Korotkov, F. Kostritsa, D. Landhuis, P. Laptev, A. Locharla, E. Lucero, O. Martin, J. R. McClean, M. McEwen, K. C. Miao, M. Mohseni, S. Montazeri, W. Mruczkiewicz, J. Mutus, O. Naaman, M. Neeley, C. Neill, M. Y. Niu, T. E. O'Brien, A. Opremcak, B. Pato, A. Petukhov, N. C. Rubin, D. Sank, V Shvarts, D. Strain, M. Szalay, B. Villalonga, T. C. White, Z. Yao, P. Yeh, J. Yoo, A. Zalcman, H. Neven, S. Boixo, A. Megrant, Y. Chen, J. Kelly, V Smelyanskiy, A. Kitaev, M. Knap, F. Pollmann, P. Roushan
Summary: The discovery of topological order revolutionized the understanding of quantum matter and laid the theoretical groundwork for quantum error-correcting codes. By preparing the ground state of the toric code Hamiltonian on a superconducting quantum processor, researchers were able to measure topological entanglement entropy and simulate anyon interferometry. Investigating aspects of the surface code, including logical state injection and the decay of nonlocal order parameter, showed the potential of quantum processors in studying topological quantum matter and error correction mechanisms.
Article
Quantum Science & Technology
E. Dumur, K. J. Satzinger, G. A. Peairs, M-H Chou, A. Bienfait, H-S Chang, C. R. Conner, J. Grebel, R. G. Povey, Y. P. Zhong, A. N. Cleland
Summary: This research explores the use of surface acoustic waves in quantum communication, demonstrating a single-phonon surface acoustic wave transmission line that links two quantum qubit nodes. It enables the coherent transfer of quantum information and the generation of a two-node Bell state.
NPJ QUANTUM INFORMATION
(2021)
Article
Nanoscience & Nanotechnology
Cecile X. Yu, Simon Zihlmann, Jose C. Abadillo-Uriel, Vincent P. Michal, Nils Rambal, Heimanu Niebojewski, Thomas Bedecarrats, Maud Vinet, Etienne Dumur, Michele Filippone, Benoit Bertrand, Silvano De Franceschi, Yann-Michel Niquet, Romain Maurand
Summary: Strong intrinsic spin-orbit interaction in silicon enables strong spin-photon coupling with a frequency of 300 MHz, which is promising for scalable quantum information processing. Coupling semiconductor quantum dots to superconducting microwave resonators allows for fast non-demolition readout and on-chip connectivity. By leveraging the strong spin-orbit interaction in silicon, a spin-photon coupling rate of 330 MHz is achieved, surpassing the spin-photon decoherence rate and paving the way for circuit quantum electrodynamics with spins in semiconductor quantum dots.
NATURE NANOTECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
H. Qiao, E. Dumur, G. Andersson, H. Yan, M. -H. Chou, J. Grebel, C. R. Conner, Y. J. Joshi, J. M. Miller, R. G. Povey, X. Wu, A. N. Cleland
Summary: Linear optical quantum computing is an ideal approach to quantum computing, requiring only a small number of computational elements. The similarity between photons and phonons suggests the potential for using phonons instead of photons in linear mechanical quantum computing. In this study, we demonstrate a beam splitter element with single phonons by using two superconducting qubits for full characterization. We also show two-phonon interference using the beam splitter, a requirement for two-qubit gates in linear computing. This advances a new solid-state system for implementing linear quantum computing and provides a straightforward conversion between itinerant phonons and superconducting qubits.
Article
Physics, Applied
Haoxiong Yan, Xuntao Wu, Andrew Lingenfelter, Yash J. Joshi, Gustav Andersson, Christopher R. Conner, Ming-Han Chou, Joel Grebel, Jacob M. Miller, Rhys G. Povey, Hong Qiao, Aashish A. Clerk, Andrew N. Cleland
Summary: In this Letter, we present and implement a multi-stage bandpass Purcell filter that enhances qubit protection, increases measurement bandwidth, and improves multiplexed capacity. Our experimental results demonstrate the flexibility of the transmission-line-based implementation, which can be integrated with current scaled-up, long coherence time superconducting quantum processors.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Cristobal Lledo, Remy Dassonneville, Adrien Moulinas, Joachim Cohen, Ross Shillito, Audrey Bienfait, Benjamin Huard, Alexandre Blais
Summary: Cavity quantum electrodynamics (QED) uses a cavity to enhance the interaction between light and matter, and has become an important tool for studying quantum optics and quantum computation. The authors demonstrate that by using a tailored external tone to destructively interfere with the cavity field, a transmon qubit can be protected from undesired effects.
NATURE COMMUNICATIONS
(2023)
