Article
Quantum Science & Technology
William J. Huggins, Jarrod R. McClean, Nicholas C. Rubin, Zhang Jiang, Nathan Wiebe, K. Birgitta Whaley, Ryan Babbush
Summary: Variational algorithms show promise in utilizing near-term quantum devices for modeling electronic states of molecular systems. By presenting a measurement strategy based on low-rank factorization of the two-electron integral tensor, this study achieves a significant reduction in computation complexity and measurement time. Although a linear-depth circuit is required before measurement, efficient postselection enables powerful error mitigation.
NPJ QUANTUM INFORMATION
(2021)
Article
Multidisciplinary Sciences
J. M. Pino, J. M. Dreiling, C. Figgatt, J. P. Gaebler, S. A. Moses, M. S. Allman, C. H. Baldwin, M. Foss-Feig, D. Hayes, K. Mayer, C. Ryan-Anderson, B. Neyenhuis
Summary: The QCCD proposal outlines a blueprint for a universal quantum computer using mobile ions as qubits, limiting quantum interactions to small ion crystals to maintain low error rates demonstrated in small experiments. The integration of necessary elements into a programmable trapped-ion quantum computer has led to the realization of a teleported CNOT gate with negligible crosstalk error and high quantum volume, showing the potential for high-performance quantum computers.
Article
Physics, Multidisciplinary
Eli Chertkov, Justin Bohnet, David Francois, John Gaebler, Dan Gresh, Aaron Hankin, Kenny Lee, David Hayes, Brian Neyenhuis, Russell Stutz, Andrew C. Potter, Michael Foss-Feig
Summary: An experiment with a trapped-ion quantum processor demonstrates the efficient simulation of the evolution of infinite entangled states using holographic technique and quantum tensor-network methods. The results show excellent quantitative agreement with theoretical predictions, indicating the potential of practical quantum computational advantage in science and technology.
Article
Quantum Science & Technology
M. Malinowski, D. T. C. Allcock, C. J. Ballance
Summary: This paper addresses the wiring challenge of trapped-ion quantum computers by introducing the WISE architecture. The WISE architecture integrates simple switching electronics into the ion-trap chip, reducing the I/O requirements without compromising performance. By using the WISE architecture, a fully connected 1000-qubit trapped-ion quantum computer can be operated at a speed of approximately 40-2600 quantum gate layers per second.
Article
Multidisciplinary Sciences
Pavel Hrmo, Benjamin Wilhelm, Lukas Gerster, Martin W. van Mourik, Marcus Huber, Rainer Blatt, Philipp Schindler, Thomas Monz, Martin Ringbauer
Summary: Quantum information carriers naturally occupy high-dimensional Hilbert spaces, and high-dimensional (qudit) quantum systems are becoming a powerful resource for quantum processors. Generating the desired interaction efficiently in these systems is crucial. In this study, the authors demonstrate the implementation of a native two-qudit entangling gate up to dimension 5 in a trapped-ion system. They use a light-shift gate mechanism to generate genuine qudit entanglement in a single application of the gate, which seamlessly adapts to the local dimension of the system with a calibration overhead independent of the dimension. Native entangling techniques for qudits are important for encoding quantum information.
NATURE COMMUNICATIONS
(2023)
Article
Quantum Science & Technology
Mingyu Kang, Qiyao Liang, Ming Li, Yunseong Nam
Summary: To achieve high-fidelity operations on a large-scale quantum computer, the parameters of the physical system must be efficiently characterized with high accuracy. For trapped ions, the entanglement between qubits is mediated by the motional modes of the ion chain, and thus characterizing the motional-mode parameters becomes essential. In this paper, physical models are developed to accurately predict both magnitude and sign of the Lamb-Dicke parameters when the modes are probed in parallel. An advanced characterization protocol is also devised to significantly shorten the characterization time compared to the conventional method.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Applied
D. T. C. Allcock, W. C. Campbell, J. Chiaverini, I. L. Chuang, E. R. Hudson, I. D. Moore, A. Ransford, C. Roman, J. M. Sage, D. J. Wineland
Summary: This article outlines an alternative approach for flexible encoding capabilities in single-species trapped ion systems using long-lived metastable states as a programmable second species. The additional trapped ion primitives needed for this protocol are compatible with large-scale systems already in operation.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Multidisciplinary
Lupei Qin, Yingxin Liu
Summary: In this work, a comprehensive analysis is carried out for the weak-value-amplification (WVA) measurement in a single trapped Ca-40(+) ion system. The meter's shift, the distribution profile of the output data, and its variance width are investigated, and the quality of the WVA measurement is characterized using the signal-to-noise ratio criterion and the Fisher information. A detailed comparison with conventional measurement is presented. The study also explores the imaginary WVA measurement.
Article
Physics, Multidisciplinary
Reinhold Blumel, Nikodem Grzesiak, Nhung H. Nguyen, Alaina M. Green, Ming Li, Andrii Maksymov, Norbert M. Linke, Yunseong Nam
Summary: To scale up quantum processors and achieve quantum advantage, a new gate-optimizing principle has been introduced to trade off negligible amounts of gate fidelity for substantial savings in power, leading to significant increases in gate speed and/or qubit connectivity. This method has been experimentally verified on a trapped-ion quantum computer and provides increased robustness to mode drift.
PHYSICAL REVIEW LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Yu Dian Lim, Hong Yu Li, Peng Zhao, Jing Tao, Luca Guidoni, Chuan Seng Tan
Summary: Silicon photonics structures for optical addressing of trapped ions in quantum computing applications were developed in this study. Grating-waveguide-grating structures of various designs were fabricated, with gratings of 25 and 30 mu m radius of curvature showing lower power loss and better-focused beam profiles compared to those with 12 and 15 mu m radius of curvature. The beam width ranged between 17.31 to 41.54 mu m, allowing for optical addressing of 2 to 4 Sr+ ions trapped along the ground electrode of the ion trap.
IEEE PHOTONICS JOURNAL
(2021)
Article
Optics
Prajit Dhara, Norbert M. Linke, Edo Waks, Saikat Guha, Kaushik P. Seshadreesan
Summary: Trapped ions have the potential to serve as quantum repeaters in long distance quantum communication due to their advanced technology platform. The use of hybrid traps with two distinct species of ions can enhance the entanglement distribution rate, making trapped-ion systems more feasible and important in this field.
Article
Quantum Science & Technology
Nikodem Grzesiak, Andrii Maksymov, Pradeep Niroula, Yunseong Nam
Summary: This article discusses the importance of parallel operations in quantum computing and the advantages of EASE gates. By implementing EASE gates in parallel, efficient quantum circuits can be realized on trapped-ion quantum computers, which is significant for quantum chemistry simulations and pattern matching algorithms.
Article
Chemistry, Physical
Ke Sun, Chao Fang, Mingyu Kang, Zhendian Zhang, Peng Zhang, David N. N. Beratan, Kenneth R. R. Brown, Jungsang Kim
Summary: This study presents a quantum simulation method to investigate the impact of light polarization on electron transfer between molecules. By controlling the quantum states of trapped atomic ions, we can simulate electron transfer dynamics resembling those in molecules. Using three-level systems instead of traditional two-level systems enhances simulation efficiency and fidelity. We analyze the transfer efficiency by considering the quantum interference of electron coupling pathways and examine potential error sources in the quantum simulations. Trapped-ion systems offer favorable scalability compared to classical computers, enabling richer electron transfer simulations.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Quantum Science & Technology
F. R. Lebrun-Gallagher, N. Johnson, M. Akhtar, S. Weidt, D. Bretaud, S. J. Hile, A. Owens, F. Bonus, W. K. Hensinger
Summary: Microfabricated ion-trap devices offer a promising pathway towards scalable quantum computing. The development of large-scale ion-trap arrays and networks faces challenges in thermal management. This research presents a modular cooling system for multiple ion-trapping experiments.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Marco Majland, Rasmus Berg Jensen, Mads Greisen Hojlund, Nikolaj Thomas Zinner, Ove Christiansen
Summary: The excessive measurement overheads in estimating physical quantities hinder the demonstration of practical quantum advantages for near-term devices. However, the reduction in resource requirements for computing anharmonic, vibrational states remains unexplored compared to its electronic counterpart. Through the manipulation of vibrational systems, such as employing coordinate transformations, we can significantly reduce the number of measurements needed to estimate anharmonic, vibrational states.
Article
Physics, Multidisciplinary
Kai Luo, Wenhui Huang, Ziyu Tao, Libo Zhang, Yuxuan Zhou, Ji Chu, Wuxin Liu, Biying Wang, Jiangyu Cui, Song Liu, Fei Yan, Man-Hong Yung, Yuanzhen Chen, Tongxing Yan, Dapeng Yu
Summary: A highly efficient and scalable two-qutrit quantum gate is proposed and demonstrated in superconducting quantum circuits. The scheme utilizes a tunable coupler to control the cross-Kerr coupling between two qutrits, achieving a fidelity of 89.3% for a two-qutrit conditional phase gate. An EPR state of two qutrits is prepared with a fidelity of 95.5% using this gate. The scheme offers both high efficiency and low crosstalk between qutrits, making it friendly for scaling up. This Letter represents an important advance towards scalable qutrit-based quantum computation.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Zi-Jian Zhang, Jinzhao Sun, Xiao Yuan, Man-Hong Yung
Summary: We propose an adaptive approach to construct a low-depth time evolution circuit by introducing a measurable quantifier that characterizes the simulation error and using an adaptive strategy to learn the shallow quantum circuit that minimizes that error. Numerical tests on electronic Hamiltonians of the H2O and H-4 molecules, as well as the transverse field Ising model with random coefficients, demonstrate that our method can significantly reduce the circuit depth while maintaining the simulation accuracy compared to the first-order Suzuki-Trotter product formula. Applications of the method in simulating many-body dynamics and solving energy spectra with the quantum Krylov algorithm are also shown.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Pauric Bannigan, Zeqing Bao, Riley J. Hickman, Matteo Aldeghi, Florian Hase, Alan Aspuru-Guzik, Christine Allen
Summary: Long-acting injectables are considered promising for chronic disease treatment, and this study demonstrates the use of machine learning to predict drug release and guide the design of new formulations. The data-driven approach has the potential to reduce development time and cost.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Medicinal
Po-Yu Kao, Ya-Chu Yang, Wei-Yin Chiang, Jen-Yueh Hsiao, Yudong Cao, Alex Aliper, Feng Ren, Alan Aspuru-Guzik, Alex Zhavoronkov, Min-Hsiu Hsieh, Yen-Chu Lin
Summary: This article explores the application of hybrid quantum-classical generative adversarial networks (GAN) in drug discovery. By substituting each element of GAN with a variational quantum circuit (VQC), small molecule discovering is achieved. Applying VQC in both the noise generator and discriminator, it can generate small molecules with better physicochemical properties and performance while having fewer trainable parameters. However, the hybrid quantum-classical GANs still face challenges in generating unique and valid molecules compared to their classical counterparts.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2023)
Article
Physics, Multidisciplinary
C. Munuera-Javaloy, A. Tobalina, J. Casanova
Summary: Ensembles of nitrogen-vacancy centers are used to detect nuclear magnetic resonance signals from micron-sized samples. The large magnetic field regime is of particular interest due to the high thermal polarization and accessibility of chemical shifts and J couplings. However, coupling NV-based sensors with high-frequency nuclear signals has been challenging. This Letter presents a method that overcomes this obstacle and achieves high spectral resolutions, limited only by the coherence of the nuclear spin signal.
PHYSICAL REVIEW LETTERS
(2023)
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)
Review
Physics, Multidisciplinary
Bin Cheng, Xiu-Hao Deng, Xiu Gu, Yu He, Guangchong Hu, Peihao Huang, Jun Li, Ben-Chuan Lin, Dawei Lu, Yao Lu, Chudan Qiu, Hui Wang, Tao Xin, Shi Yu, Man-Hong Yung, Junkai Zeng, Song Zhang, Youpeng Zhong, Xinhua Peng, Franco Nori, Dapeng Yu
Summary: In the past decade, quantum computers have made remarkable progress and achieved key milestones towards universal fault-tolerant quantum computers. Quantum hardware has become more integrated and architectural, surpassing the fault-tolerant threshold in controlling various physical systems. Quantum computation research has embraced industrialization and commercialization, shaping a vibrant environment that accelerates the development of this field, now in the noisy intermediate-scale quantum era.
FRONTIERS OF PHYSICS
(2023)
Article
Multidisciplinary Sciences
Yue Ban, E. Torrontegui, J. Casanova
Summary: We propose quantum neural networks with multi-qubit interactions, which can reduce the network depth without losing approximative power. We demonstrate that introducing multi-qubit potentials in quantum perceptrons enables more efficient information processing tasks and allows for the construction of distinct entangling quantum gates. This simplification in the network architecture addresses the connectivity challenge and facilitates the scalability and training of quantum neural networks.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Medicinal
Stanley Lo, Martin Seifrid, Theeophile Gaudin, Alaan Aspuru-Guzik
Summary: One of the biggest challenges in polymer property prediction is finding an effective representation that accurately captures the sequence of repeat units. Inspired by data augmentation techniques in computer vision and natural language processing, we explore rearranging the molecular representation iteratively while preserving connectivity to augment polymer data and reveal additional substructural information. We evaluate the impact of this technique on machine learning models trained on three polymer datasets and compare it to common molecular representations. Data augmentation does not significantly improve machine learning property prediction performance compared to non-augmented representations, except in datasets where the target property is primarily influenced by the polymer sequence.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2023)
Article
Chemistry, Physical
Philipp Schleich, Joseph Boen, Lukasz Cincio, Abhinav Anand, Jakob S. Kottmann, Sergei Tretiak, Pavel A. Dub, Alan Aspuru-Guzik
Summary: The limited availability of noisy qubits in current quantum computing hardware restricts the investigation of larger, more complex molecules in quantum chemistry calculations. In this study, a classical and near-classical treatment within the framework of quantum circuits is explored. A product ansatz for the parametrized wavefunction is used, along with post-treatment to account for interactions between subsystems. The circuit structure is molecule-dependent and is constructed using simulated annealing and genetic algorithms.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Physics, Applied
Lucas C. Celeri, Daniel Huerga, Francisco Albarran-Arriagada, Enrique Solano, Mikel Garcia de Andoin, Mikel Sanz
Summary: Simulating quantum many-body systems is challenging, especially for fermionic systems due to the emergence of nonlocal interactions. We present a digital-analog quantum algorithm that can simulate a wide range of fermionic Hamiltonians, including the well-known Fermi-Hubbard model. These methods allow quantum algorithms to go beyond digital versions by efficiently utilizing coherence time. Additionally, we demonstrate a low-connected architecture for realistic digital-analog implementations of specific fermionic models.
PHYSICAL REVIEW APPLIED
(2023)
Article
Quantum Science & Technology
Pranav Chandarana, Pablo Suarez Vieites, Narendra N. Hegade, Enrique Solano, Yue Ban, Xi Chen
Summary: In this paper, we use meta-learning with recurrent neural networks to address the difficulties in finding suitable variational parameters and initial parameters for the QAOA. By combining meta-learning and counterdiabaticity, we find suitable variational parameters and reduce the number of optimization iterations required. Our method improves the performance of the state-of-the-art QAOA by offering a short-depth circuit ansatz with optimal initial parameters.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Astronomy & Astrophysics
Decheng Ma, Chenglong Jia, Enrique Solano, Lucas Chibebe Celeri
Summary: The propagation of phonons in the presence of a particle sink with radial flow in a Bose-Einstein condensate is considered. It is found that due to the particle sink, which simulates a static acoustic black hole, the phonon experiences significant spacetime curvature at a considerable distance from the sink. The trajectory of the phonons is bent after passing by the particle sink, simulating the gravitational lensing effect in a Bose-Einstein condensate. Possible experimental implementations are discussed.
Article
Physics, Multidisciplinary
Bao-Jie Liu, L. -L. Yan, Y. Zhang, M. -H. Yung, Shi-Lei Su, C. X. Shan
Summary: Nonadiabatic holonomic quantum computation (NHQC) is a promising approach for constructing robust and high-fidelity quantum gates with geometric features. However, NHQC is sensitive to decay and dephasing errors due to the requirement of an ancillary intermediate state. In this study, we use the Hamiltonian reverse engineering technique to investigate the effect of intermediate-state decoherence on NHQC gate fidelity, and propose schemes to construct single-qubit and two-qubit holonomic gates that are highly robust against decoherence. Our scheme is demonstrated with a nitrogen-vacancy center and achieves significantly improved gate fidelity and robustness compared to recent experimental NHQC schemes.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Quantum Science & Technology
Chufan Lyu, Xusheng Xu, Man -Hong Yung, Abolfazl Bayat
Summary: The variational quantum-classical algorithms are the most promising approach for achieving quantum advantage on near-term quantum simulators. Among these methods, the variational quantum eigensolver has attracted a lot of attention in recent years. The improvement of efficiency for simulating excited states of many-body systems can be achieved by exploiting the symmetries of the Hamiltonian, either by including all symmetries in the circuit design or by updating the cost function to include the symmetries. The hardware symmetry preserving approach outperforms the second approach, but integrating all symmetries in the design of the circuit could be extremely challenging. Therefore, a hybrid symmetry preserving method is introduced to divide the symmetries between the circuit and the classical cost function, allowing to harness the advantage of symmetries while preventing sophisticated circuit design.