Article
Physics, Multidisciplinary
Yong Zhang, Qian-Yu Zhang, Wen-Li Bai, Wen-Cui Peng, Sheng-Guo He, Xin Tong
Summary: We describe a method to efficiently generate ultracold hydrogen molecular ions HD+ in a segmented linear ion trap. HD+ ions are produced by [2+1 & PRIME;] resonance-enhanced multiphoton ionization (REMPI) of an HD supersonic molecular beam, and sympathetically cooled using laser-cooled Be+ ions. The selective generation of HD+ ions is achieved using 201 nm and 395 nm pulse lasers. The loading rate of HD+ ions in the ion trap is determined by comparing experimental images with simulated images of Be+-HD+ bi-component Coulomb crystals, yielding an average rate of 4.3(2) ions per second. This method enables the production of state-selected HD+ ions and enhances the signal strengths of selected rovibrational transitions.
CHINESE JOURNAL OF PHYSICS
(2023)
Article
Quantum Science & Technology
D. Kalincev, L. S. Dreissen, A. P. Kulosa, C-H Yeh, H. A. Fuerst, T. E. Mehlstaeubler
Summary: The study demonstrates consistent heating rates in a linear radio frequency Paul trap for single ions and extended ion crystals, stable electric field noise, and a quadratic relationship between ion displacement and radio frequency noise-induced heating for the center-of-mass mode in linear chains. Additionally, changing the quality factor of the resonant rf circuit can impact the level of rf noise, and the heating of motional modes in extended crystals is influenced by crystal symmetry and the specific mode being studied.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Fluids & Plasmas
F. Sattin, D. F. Escande
Summary: Stochastic heating is a mechanism to energize magnetized particles using low-frequency electromagnetic waves. This study reveals that even weak spatial inhomogeneity can eliminate the threshold requirement for wave amplitude, replacing it with a requirement on the interaction duration between the wave and particle. This thresholdless chaotic mechanism may have applications in other inhomogeneous systems.
Article
Multidisciplinary Sciences
Travis Severt, Zachary L. Streeter, Wael Iskandar, Kirk A. Larsen, Averell Gatton, Daniel Trabert, Bethany Jochim, Brandon Griffin, Elio G. Champenois, Matthew M. Brister, Dylan Reedy, Demitri Call, Richard Strom, Allen L. Landers, Reinhard Doerner, Joshua B. Williams, Daniel S. Slaughter, Robert R. Lucchese, Thorsten Weber, C. William McCurdy, Itzik Ben-Itzhak
Summary: In this study, the authors successfully separate the sequential breakup pathways in the double ionization of water molecules and experimentally identify, separate, and sequentially track the two fragmentation paths of the intermediate OD+ ion. Determining the time evolution of reactions at the quantum mechanical level is crucial for understanding molecular dynamics.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Ping Tang, Ken-ichi Uchida, Gerrit E. W. Bauer
Summary: We predict a nonlocal ferron-drag effect in a ferroelectric on top of a metallic film, where an electric current in the conductor generates a heat current in the ferroelectric through long-range charge-dipole interactions. The nonlocal Peltier and Seebeck effects can be controlled by electric gates and detected thermographically. We predict significant effects for van der Waals ferroelectric films on graphene.
Article
Chemistry, Physical
Farzaneh Ziaee, Kurtis Borne, Ruaridh Forbes, P. Kanaka Raju, Yubaraj Malakar, Balram Kaderiya, Travis Severt, Itzik Ben-Itzhak, Artem Rudenko, Daniel Rolles
Summary: The UV-induced photodissociation dynamics of iodomethane (CH3I) in its A-band were studied using time-resolved coincident ion momentum imaging and strong-field ionization as a probe. The distribution of photofragments resulting from double ionization of the molecule revealed the cleavage of carbon-iodine bond and the influence of a potential well in the di-cationic potential energy surfaces on the observed distribution. The competition between single- and multi-photon excitation and ionization of the molecule was investigated as a function of UV-pump laser pulse intensity. Two-photon excitation to Rydberg states was identified by the transformation of delay-dependent iodomethane yield, while dissociative ionization induced by absorption of three UV photons was observed in the kinetic energy of fragment ions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Ziwan Du, Yuxuan Lai, Ruirong Bai, Bolun Wang, Qiang Zheng, Chuan Xu, Teng Lu, Jun Pei, Wei Li, Yu-Ning Wu, Kai Liu, Yun Liu, Engang Fu, Jing-Feng Li, Yigang Yang, Qian Li
Summary: Direct neutron detection based on semiconductor crystals is being advanced by the development of high-quality centimeter-sized LiInP2Se6 single crystals using the Bridgman method. Prototype detectors fabricated from these crystals demonstrate high energy resolution and robust response spectra to alpha-particles and thermal neutrons. Insights into the carrier trapping process are also identified, providing critical information for improving the energy resolution of LiInP2Se6 bulk crystals and potentially adopting single crystals in new-generation neutron detectors.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
Markus Teller, Dario A. Fioretto, Philip C. Holz, Philipp Schindler, Viktor Messerer, Klemens Schueppert, Yueyang Zou, Rainer Blatt, John Chiaverini, Jeremy Sage, Tracy E. Northup
Summary: This study introduces a method to predict the impact of dielectric materials on the motion of trapped ions, and demonstrates quantitative agreement between a model without free parameters and measurements of trapped ions near dielectric mirrors. This approach is expected to optimize the design of ion-trap-based quantum computers and network nodes.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Physical
Xiaopei Zhu, Lina Cheng, Han Yu, Feifei Xu, Wei Wei, Li-Zhen Fan
Summary: This study systematically investigates the relationship between microstructural characteristics and rate performance in a pouch cell with LiNi0.5Mn0.3Co0.2O2/artificial graphite lithium ion battery. The research reveals that the (001) plane microtexture of the electrode surface structure significantly affects the rate capability, leading to diffusion resistance of lithium ions and high interfacial resistance. These findings offer guidance for developing lithium batteries with high rate and long cycle life.
JOURNAL OF MATERIOMICS
(2022)
Article
Engineering, Environmental
Wenbiao Liang, Feng Jin, Yin Zhao, Liyi Shi, Quan Liu, Zhuyi Wang, Yi Wang, Meihong Zhang, Jiefang Zhu, Shuai Yuan
Summary: The single-crystal LiNi0.8Mn0.1Co0.1O2 (SC-NCM811) cathode with electro-chemo-mechanically compliant microstructure was successfully synthesized by microfluidic technology combined with the solid-state lithiation process. The optimized SC-NCM811 cathode has a small grain size, low cation mixing, and well layered structure, showing good electrochemical performance. Microfluidic technology is expected to provide a new strategy for preparing single-crystal Ni-rich cathode materials, which may extend to the commercial application of other cathode materials.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Physics, Multidisciplinary
A. M. Hansen, K. L. Nguyen, D. Turnbull, B. J. Albright, R. K. Follett, R. Huff, J. Katz, D. Mastrosimone, A. L. Milder, L. Yin, J. P. Palastro, D. H. Froula
Summary: Cross-beam energy transfer (CBET) saturation in gas-jet plasma is investigated using Thomson scattering to measure ion heating. The experiments show that for high-intensity interactions, ion-acoustic waves saturate and lead to a significant increase in ion temperature. Particle-in-cell simulations and linear kinetic CBET models are consistent with measurements, demonstrating good agreement with observed energy transfer in the plasma conditions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Fluids & Plasmas
Evgeny Stambulchik, Carlos A. Iglesias
Summary: Spectral line broadening by plasmas can be computed by solving the equation of motion for the radiating system in a fluctuating potential obtained from computer simulations. Previous calculations have focused on the dipole term in the multipole expansion, but higher multipoles and plasma perturbers overlapping the bound electron wave functions become important at higher densities. By using analytical formulas for atomic matrix elements, a computer simulation approach that considers the full radiator-plasma interaction is developed, removing strong collision divergences and accounting for the plasma polarization shift. The model is applied to hydrogenic argon spectral lines in a dense argon plasma, relevant to plasma diagnostic techniques.
Article
Chemistry, Analytical
Ping Hu, Ying Zhang, Dandan Wang, Guohua Qi, Yongdong Jin
Summary: In this study, a novel cG-nanopore was developed for the specific detection of intracellular GSH in single cells. The method showed good responsiveness and selectivity, successfully quantifying the changes in GSH content in single cells incubated with drugs.
ANALYTICAL CHEMISTRY
(2021)
Article
Materials Science, Ceramics
Pengfei Zhang, Zhaofeng Liu, Ben Ma, Ping Li, Yingke Zhou, Xiaohui Tian
Summary: This study prepared single crystal LiNi0.8Co0.1Mn0.1O2 materials through a multiple-step calcination process, and further improved their Li storage performance by controllably doping with fluorine. This enhancement in lithium ion diffusion and crystal structure stability led to a remarkable specific capacity and high capacity retention after cycling, making them promising for application in lithium-ion batteries.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Yujing Bi, Yaobin Xu, Ran Yi, Dianying Liu, Peng Zuo, Jiangtao Hu, Qiuyan Li, Jing Wu, Chongmin Wang, Sha Tan, Enyuan Hu, Jingnan Li, Rebecca O'Toole, Liu Luo, Xiaoguang Hao, Subramanian Venkatachalam, Job Rijssenbeek, Jie Xiao
Summary: A new nanoscale phase separation process has been discovered to promote the growth and segregation of single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811). This process occurs directly during high-temperature calcination without significant agglomeration. The conversion of transition metal hydroxide precursors into transition metal oxide intermediates before reacting them with lithium salt is the key factor.
ENERGY STORAGE MATERIALS
(2023)
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
Computer Science, Hardware & Architecture
Prakash Murali, Dripto M. Debroy, Kenneth R. Brown, Margaret Martonosi
Summary: Trapped ions (TIs) are a leading candidate for building Noisy Intermediate-Scale Quantum (NISQ) hardware. A modular architecture named Quantum Charge Coupled Device (QCCD) has been proposed to achieve 50-100 qubit TI devices. Extensive architectural studies have been performed to evaluate the design choices and provide recommendations for highly reliable and performant application executions. The insights from these studies have the potential to influence quantum computing hardware in the near future.
COMMUNICATIONS OF THE ACM
(2022)
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, 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)