Article
Chemistry, Multidisciplinary
Ji-Hoon Kang, Junghee Ryu, Hoon Ryu
Summary: This study theoretically investigates charge stabilities and spin-based quantum bit operations in Si double quantum dot systems, exploring various aspects such as electron reservoir designs, electrostatic controls of quantum dot shapes, and spin qubit manipulation. The effects of DC control biases and geometric symmetries on the Rabi cycle of spin qubits are examined, with solid connections to experimental results being established. The research provides valuable insights into the engineering details of Si DQD structures, serving as a practical guideline for potential device designs.
Article
Physics, Multidisciplinary
Kosuke Mizuno, Takaaki Takenaka, Imran Mahboob, Shiro Saito
Summary: In this study, the effect of various loss channels on the performance of logical gates on a bosonic qubit is investigated through numerical simulations. A gate error model is developed to predict experimentally achievable gate errors for bosonic qubits, providing insights into loss mechanisms and suggesting more efficient optimization algorithms to reduce gate errors.
NEW JOURNAL OF PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Menglan Lin, Jinxing Li, Dawei Zhang, Badreddine Ratni, Jianjia Yi, Peihan Qi, Kuang Zhang, Andre de Lustrac, Shah Nawaz Burokur
Summary: Superoscillation is an extraordinary phenomenon that can generate small-size focusing spots, which have potential applications in super-resolution focusing and imaging. In this study, a reconfigurable near-field focusing reflector based on the superoscillation principle is elaborated, where the focal position and operation frequencies can be modulated by the dynamic phase-compensation mechanism of an engineered metamirror. Experimentally measured in an anechoic chamber, the fabricated metamirror platform demonstrates subdiffraction near-field focusing and flexible manipulation of focal distances and frequencies. The proposed focusing reflector holds great integration potential in imaging devices due to its tunability, high resolution, and nonnarrowband features.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Chemistry, Analytical
Riaz Muhammad, Kay Thwe Htun, Ezekiel Edward Nettey-Oppong, Ahmed Ali, Dae Keun Jeon, Hyun-Woo Jeong, Kyung Min Byun, Seung Ho Choi
Summary: Pulse oximetry is a non-invasive method for measuring blood oxygen saturation, but single-point measurements can be influenced by various factors. To address this issue, we developed a novel illumination system for a pulse oximetry imaging system, which allows for consistent and spatially uniform measurements of oxygen saturation.
Article
Physics, Multidisciplinary
Shingo Kukita, Haruki Kiya, Yasushi Kondo
Summary: This paper studies how to control pulse length errors in quantum systems to enhance the quality of quantum technology. By searching for composite quantum gates with first-order robustness against pulse length errors, a lower bound on the operation time is found.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Physics, Applied
Zhiwen Zong, Zhenhai Sun, Zhangjingzi Dong, Chongxin Run, Liang Xiang, Ze Zhan, Qianlong Wang, Ying Fei, Yaozu Wu, Wenyan Jin, Cong Xiao, Zhilong Jia, Peng Duan, Jianlan Wu, Yi Yin, Guoping Guo
Summary: Through two different data-driven gradient-ascent pulse engineering protocols, experimental optimization of a two-qubit controlled-Z gate was achieved, demonstrating the effectiveness of these protocols in gate optimization.
PHYSICAL REVIEW APPLIED
(2021)
Article
Materials Science, Multidisciplinary
Feng Qin, Zhiyang Yan, Jinfeng Fan, Jinliang Cai, Xingzhong Zhu, Xiaogang Zhang
Summary: A transparent and stable silver nanowire-PEDOT:PSS composite film with excellent EMI shielding capability has been prepared, showing outstanding performance in both small signal and high power microwave excitation. The composite film exhibits high shielding effectiveness and optical transmittance, with good stability and uniformity. Moreover, the shielding effectiveness of the composite film increases with the excitation power density of high power microwaves, ultimately reaching saturation at a fixed power density.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2021)
Article
Optics
Hao Yuan, Gang Zhang, Chuanmei Xie, Zhanjun Zhang
Summary: This paper presents an improved BCQST scheme that fixes the security loopholes of the previous version and ensures the achievement of bidirectional control. Furthermore, the revised scheme becomes more feasible in terms of present experimental techniques.
LASER PHYSICS LETTERS
(2022)
Article
Education, Scientific Disciplines
Qile David Su
Summary: A common source of systematic error in quantum computations is imperfections in control pulses, which can be mitigated by composite pulses with a geometric interpretation. These pulse sequences can also be obtained within a quasi-classical framework, raising the question of whether error-correction procedures utilizing entanglement cannot be reproduced in the quasi-classical formulation.
EUROPEAN JOURNAL OF PHYSICS
(2021)
Article
Computer Science, Information Systems
Xiangye Wei, Liming Xiu
Summary: Stochastic computing is a method of expressing values using random bitstreams and performing computation with bitwise operations. Recently, it was discovered that deterministic bitstreams can be used for stochastic computing, resulting in 100% accurate results. However, the current circuit implementation is not practical and the expressible values for operands are limited. This article proposes a time-domain all-digital frequency synthesizer as a hardware platform for performing deterministic stochastic computing, opening up the subfield of rational number stochastic computing. The aim of this work is to create a practical tool for broadening the use of stochastic computing.
IEEE TRANSACTIONS ON EMERGING TOPICS IN COMPUTING
(2023)
Article
Engineering, Electrical & Electronic
Huan Chen, Kai Sun, Hongsheng Chong, Zhe Zhang, You Zhou, Shujun Mu
Summary: The operating process of a CLLC converter under open-loop control at the resonant frequency is significantly impacted by the nonideal parameters of the semiconductor switches and gate driver circuits, leading to decreased efficiency. A hybrid compensation scheme is proposed to minimize these effects and has been successfully verified by experiments, demonstrating reduced voltage ripple and increased efficiency within the load range.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Daying Sun, Jiayi Hu, Chong Wang, Xiong Cheng, Wenhua Gu
Summary: This article presents a delay-line DPWM architecture with a compensation module and a delay-adjustable unit based on delay-locked loop to reduce the impact of temperature or frequency changes on the input clock. A time compensation method is used to reduce errors caused by critical path delays. With a 10-bit DPWM achieved on Xilinx FPGA, the time error of the architecture decreases to around 500 ps, and the duty cycle range is from 1.63% to 98.44%.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Jino M. Pattery, Sandeep Jayaprakasan, Elizabeth P. Cheriyan, Rijil Ramchand
Summary: This paper introduces a micro compensator installed and maintained by an electric utility to improve power quality in low voltage secondary distribution systems. The micro compensator plays a role as a shunt-connected current-controlled voltage source inverter and performs reactive and harmonic compensation during peak periods, thus improving power factor and power quality. During off-peak periods, it provides dynamic reactive current support to compensate for voltage sag or voltage swell. The proposed method for calculating compensation indices is validated and experimental results show significant improvement in power quality levels.
IEEE TRANSACTIONS ON POWER DELIVERY
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Alvaro F. Vaquero, Marcos R. Pino, Manuel Arrebola
Summary: A novel approach to define masks in near-field syntheses is presented in this work, aiming to achieve uniform field distribution in a large and complex-shape area. By overcoming challenges caused by electromagnetic propagation, the technique successfully reduces starting ripple, improving the convergence of the algorithm.
2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)
(2022)
Article
Education, Scientific Disciplines
Abraham Asfaw, Alexandre Blais, Kenneth R. Brown, Jonathan Candelaria, Christopher Cantwell, Lincoln D. Carr, Joshua Combes, Dripto M. Debroy, John M. Donohue, Sophia E. Economou, Emily Edwards, Michael F. J. Fox, Steven M. Girvin, Alan Ho, Hilary M. Hurst, Zubin Jacob, Blake R. Johnson, Ezekiel Johnston-Halperin, Robert Joynt, Eliot Kapit, Judith Klein-Seetharaman, Martin Laforest, H. J. Lewandowski, Theresa W. Lynn, Corey Rae H. McRae, Celia Merzbacher, Spyridon Michalakis, Prineha Narang, William D. Oliver, Jens Palsberg, David P. Pappas, Michael G. Raymer, David J. Reilly, Mark Saffman, Thomas A. Searles, Jeffrey H. Shapiro, Chandralekha Singh
Summary: The paper provides a roadmap for constructing a quantum engineering education program to meet the workforce needs of the United States and international community. Through a workshop and drawing on best practices, the researchers make specific findings and recommendations, including the design of a first quantum engineering course accessible to all STEM students and the education and training methods for producing quantum-proficient engineers.
IEEE TRANSACTIONS ON EDUCATION
(2022)
Article
Chemistry, Physical
Christian Wellers, Magnus R. Schenkel, Gouri S. Giri, Kenneth R. Brown, Stephan Schiller
Summary: In this study, controlled loading, sympathetic cooling, mass spectrometric identification, and vibrational excitation of ultracold single HD+ ions trapped in a tightly confining radiofrequency trap are demonstrated for the first time using single laser-cooled Be+ ions for sympathetic cooling. The apparatus can also be utilized for preparing other single ions, both lighter and heavier than the coolant ion.
Article
Physics, Applied
Bichen Zhang, Swarnadeep Majumder, Pak Hong Leung, Stephen Crain, Ye Wang, Chao Fang, Dripto M. Debroy, Jungsang Kim, Kenneth R. Brown
Summary: In this paper, a method for reducing coherent errors by using hidden inverses is demonstrated. The effectiveness of this method is numerically simulated and experimentally validated on a trapped-ion quantum computer.
PHYSICAL REVIEW APPLIED
(2022)
Article
Physics, Multidisciplinary
Zhubing Jia, Ye Wang, Bichen Zhang, Jacob Whitlow, Chao Fang, Jungsang Kim, Kenneth R. Brown
Summary: The study proposes a general method to determine Fock state distributions and reconstruct the density matrix of arbitrary multimode motional states, applicable to any system with Jaynes-Cummings-type interactions.
PHYSICAL REVIEW LETTERS
(2022)
Letter
Multidisciplinary Sciences
Elis Newham, Pamela G. Gill, Michael J. Benton, Philippa Brewer, Neil J. Gostling, David Haberthuer, Jukka Jernvall, Tuomas Kankanpaa, Aki Kallonen, Charles Navarro, Alexandra Pacureanu, Kelly Richards, Kate Robson Brown, Philipp Schneider, Heikki Suhonen, Paul Tafforeau, Katherine Williams, Berit Zeller-Plumhoff, Ian J. Corfe
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Chao Fang, Ye Wang, Shilin Huang, Kenneth R. Brown, Jungsang Kim
Summary: In quantum computers, crosstalk between the target and neighboring spectator qubits due to the spillover of control signals is a major error source limiting the fidelity of two-qubit entangling gates. This study proposes a crosstalk suppression scheme that eliminates all first-order crosstalk using only local control of the target qubits, as opposed to existing schemes. Experimental results in a laser-driven trapped-ion system show high fidelity for the two-qubit Bell state, indicating the potential applicability of this scheme to other platforms with analogous interaction Hamiltonians.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
Mingyu Kang, Ye Wang, Chao Fang, Bichen Zhang, Omid Khosravani, Jungsang Kim, Kenneth R. Brown
Summary: This study develops filter functions for Molmer-Sorensen gates in trapped-ion quantum computers, accurately predicting the change in gate error due to small parameter fluctuations at any frequency. Experimental results show that using these filter functions can significantly improve gate fidelity in a five-ion chain.
PHYSICAL REVIEW APPLIED
(2023)
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
Mingyu Kang, Wesley C. Campbell, Kenneth R. Brown
Summary: For quantum error-correcting codes, erasures, or errors with known locations, are more favorable than Pauli errors. Convert physical noise into erasures can significantly enhance quantum error correction. In this study, we apply the concept of performing erasure conversion by encoding qubits into metastable atomic states, proposed by Wu, Kolkowitz, Puri, and Thompson in 2022, to trapped ions.
Article
Optics
Lu Qi, Evan C. Reed, Kenneth R. Brown
Summary: Control of the external degree of freedom is crucial for the applications of trapped molecular ions in spectroscopy, precision measurements, and quantum information technology. In this study, we demonstrate near ground-state cooling of axial motional modes of a calcium mono-oxide ion through sympathetic sideband cooling with a cotrapped calcium ion. We also observe that the phonon state of the axial out-of-phase mode of the ion chain remains unchanged while the mode frequency is adiabatically ramped up and/or down, which is essential for investigating the proposed molecular dipole-phonon interaction.
Article
Quantum Science & Technology
Theerapat Tansuwannont, Balint Pato, Kenneth R. Brown
Summary: The Shor fault-tolerant error correction (FTEC) scheme uses transversal gates and ancilla qubits in the cat state to prevent error propagation. An adaptive syndrome measurement technique is introduced to improve the scheme. Simulations show that the proposed protocols can maintain code distance, increase pseudothreshold, and reduce the average number of measurement rounds compared to the traditional Shor scheme.
Article
Optics
Zhubing Jia, Shilin Huang, Mingyu Kang, Ke Sun, Robert F. Spivey, Jungsang Kim, Kenneth R. Brown
Summary: In trapped-ion quantum computers, spin-dependent force and phonons are used to generate two-qubit entangling gates. To maintain high fidelity under fluctuating experimental parameters, robust pulse-design methods are used. An improved method is proposed that guarantees the robustness of the rotation angle against uniform mode-frequency drifts. Experimental results show significantly improved robustness and gate fidelity compared to a single frequency-modulated pulse.
Proceedings Paper
Computer Science, Theory & Methods
Aniket S. Dalvi, Filip Mazurek, Leon Riesebos, Jacob Whitlow, Swarnadeep Majumder, Kenneth R. Brown
Summary: Duke ARTIQ Extensions (DAX) provides a framework for modular control software in ion-trap quantum systems, while DAX.program-sim (DPS) framework allows for simulation of quantum programs at the level of quantum operations. This simulation addition is essential for testing and benchmarking quantum hardware. The DPS pipeline has the same input as the hardware, enabling flexible simulation options.
2022 IEEE INTERNATIONAL CONFERENCE ON QUANTUM COMPUTING AND ENGINEERING (QCE 2022)
(2022)
Proceedings Paper
Computer Science, Theory & Methods
Leon Riesebos, Kenneth R. Brown
Summary: Modern quantum computers heavily rely on real-time control systems for operation. However, testing real-time control software is often complex, and existing simulation software is not practical for software testing. To address this issue, we developed an interactive simulator that can simulate signals at the application programming interface level. Our simulation infrastructure achieves an average 6.9 times faster simulation speed compared to hardware execution, with an average accuracy of 97.9% in simulating the position of the timeline cursor when the appropriate configuration is chosen.
2022 IEEE INTERNATIONAL CONFERENCE ON QUANTUM COMPUTING AND ENGINEERING (QCE 2022)
(2022)
Proceedings Paper
Computer Science, Theory & Methods
Leon Riesebos, Brad Bondurant, Jacob Whitlow, Junki Kim, Mark Kuzyk, Tianyi Chen, Samuel Phiri, Ye Wang, Chao Fang, Andrew Van Horn, Jungsang Kim, Kenneth R. Brown
Summary: Real-time control software and hardware are crucial for operating quantum computers. This study proposes a systematic design strategy for modular real-time quantum control software, which can significantly reduce the execution time overhead of kernels without increasing the binary size. The experiment demonstrates the modularity and portability of the software architecture on two different ion-trap quantum systems.
2022 IEEE INTERNATIONAL CONFERENCE ON QUANTUM COMPUTING AND ENGINEERING (QCE 2022)
(2022)