Article
Physics, Multidisciplinary
Wenbing Li, Sebastian Wolf, Lukas Klein, Dmitry Budker, Christoph E. Duellmann, Ferdinand Schmidt-Kaler
Summary: We demonstrate the implementation of three-dimensional polarization gradient cooling (PGC) for trapped ions. The cooling method is robust against an elevated phonon occupation number and works continuously in different cooling regimes. However, the performance of PGC strongly depends on residual micromotion and the spectral impurity of the laser field.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
Alexander Kato, Andrei Nomerotski, Boris B. Blinov
Summary: We propose and demonstrate a method for Doppler cooling trapped-ion crystals with large and uneven distribution of micromotion amplitudes. The technique uses synchronized pulses of Doppler cooling light with the trap rf to selectively target ions near a node in their velocity, resulting in more uniform cooling across the crystal using a single tone of cooling light. We present a theoretical framework that describes the practicality of this technique and provide a simple experimental demonstration.
Article
Optics
A. J. Rasmusson, Marissa D'Onofrio, Yuanheng Xie, Jiafeng Cui, Philip Richerme
Summary: A framework for calculating the fastest possible pulsed sideband cooling sequence was introduced and its improvement compared to traditional methods was verified. The ion's motional distribution was found to be distinctly nonthermal after cooling, making standard thermometry techniques unusable.
Article
Physics, Multidisciplinary
C. Will, M. Bohman, T. Driscoll, M. Wiesinger, F. Abbass, M. J. Borchert, J. A. Devlin, S. Erlewein, M. Fleck, B. Latacz, R. Moller, A. Mooser, D. Popper, E. Wursten, K. Blaum, Y. Matsuda, C. Ospelkaus, W. Quint, J. Walz, C. Smorra, S. Ulmer
Summary: This article focuses on the remote sympathetic cooling of a single proton with laser-cooled Be-9(+) ions. Through analytical calculations and numerical simulations, two cooling schemes capable of achieving proton temperatures of about 10 mK in short cooling times are identified. These techniques allow for improved sampling rates and reduced systematic uncertainties in precision measurements based on trapped charged particles.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
Chung-Hsien Wang, Yi-Cheng Wang, Chi-Chih Chen, Chun-Che Wang, H. H. Jen
Summary: We demonstrate an enhanced dark-state sideband cooling in trapped atoms utilizing photon-mediated dipole-dipole interactions among them. By placing the atoms at the magic interparticle distances, we achieve an outperformed cooling behavior in the target atom that surpasses the limit of a single atom. Our results provide insights into subrecoil cooling of atoms with collective and light-induced long-range dipole-dipole interactions and pave the way for implementing genuine quantum operations in multiple quantum registers.
Article
Chemistry, Physical
Richard Karl, Yanning Yin, Stefan Willitsch
Summary: Hybrid traps, which combine different types of external fields, have become important tools for studying interactions between neutral particles and ions at low temperatures. This study uses molecular-dynamics simulations to investigate the effect of a strongly inhomogeneous magnetic field on the trapping and laser cooling of a single Ca+ ion in a radiofrequency trap. The results show that laser cooling is still effective despite the ion experiencing different magnetic field strengths and directions along its trajectory. Offsettting the centers of the two traps creates a linear magnetic-field gradient, requiring multiple lasers to address the resulting Zeeman splittings for efficient cooling.
Article
Optics
J. C. Shaw, S. Hannig, D. J. McCarron
Summary: The study introduces a high-power tunable deep-ultraviolet laser system that uses harmonic generation to produce high-power DUV laser and performs second harmonic generation in an unexplored high intensity regime, providing new possibilities for applications in the field of optical physics.
Article
Optics
Sourav Dutta, Bubai Rahaman
Summary: We present a Littrow-type 671-nm external cavity diode laser (ECDL) with enhanced passive stability and output power exceeding 150 mW. The laser achieves wavelength tuning by displacing the diffraction grating horizontally about an optimal pivot point. The compact and robust design, including the use of titanium and a stiff lightweight diffraction grating-arm, improves stability and reduces susceptibility to mechanical vibrations. The ECDL has a linewidth of approximately 360 kHz and is successfully employed for laser cooling and trapping of lithium atoms in a magneto-optical trap. This cost-effective design can be adapted to other wavelengths using off-the-shelf laser diodes without anti-reflection coating.
Article
Engineering, Electrical & Electronic
Qilong Liu, Lucien J. Breems, Shagun Bajoria, Muhammed Bolatkale, Robert Rutten, Georgi Radulov
Summary: This article presents a 5-GS/s continuous-time multi-stage noise-shaping analog-to-digital converter. The ADC utilizes a RC-hybrid stabilization DAC to compensate for the loop delay and phase shift and employs delay matching all-pass input filter with a low-pass feedforward filter to suppress input signal leakage. The ADC achieves high dynamic range and signal-to-noise ratio while consuming low power.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2022)
Article
Optics
J. Mielke, J. Pick, J. A. Coenders, T. Meiners, M. Niemann, J. M. Cornejo, S. Ulmer, C. Ospelkaus
Summary: The study demonstrates the phase locking of two UV laser sources through electro-optic modulation, sum frequency generation, and second harmonic generation, translating the frequency offset to the UV domain for thermometry of Be-9(+) ions. This technique may be utilized for sideband cooling of single Be-9(+) ions and future sympathetic cooling schemes and quantum-logic-based measurements in Penning traps.
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
(2021)
Article
Optics
Hsin-Jia Huang, Yu-Han Fang, Chun-Ling Chen, Hsing-Chih Liang, Yung-Fu Chen
Summary: Two compact laser sources at 707 and 714 nm are efficiently realized using the diode-pumped Nd:YVO4 laser with stimulated Raman scattering and sum-frequency generation. The necessary wavelengths are achieved through Raman scattering and SFG in specific crystals, resulting in high output powers. These laser sources are practically useful in laser trapping and cooling related to atomic strontium and radium.
Article
Physics, Multidisciplinary
Qiming Wu, Yue Shi, Jiehang Zhang
Summary: We demonstrate continuous Raman sideband cooling beyond the Lamb-Dicke regime, achieving close to the motional ground state for a long ion chain. By driving multiple sideband transitions simultaneously, we cool nearly all axial modes of a 24-ion chain to the ground state, with a large LD parameter of eta = 1.3 and a wide bandwidth of 4 MHz. This technique is crucial for large-scale quantum information processing with linear ion chains and can be applied to other atomic and molecular systems.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Multidisciplinary Sciences
M. J. Borchert, J. A. Devlin, S. R. Erlewein, M. Fleck, J. A. Harrington, T. Higuchi, B. M. Latacz, F. Voelksen, E. J. Wursten, F. Abbass, M. A. Bohman, A. H. Mooser, D. Popper, M. Wiesinger, C. Will, K. Blaum, Y. Matsuda, C. Ospelkaus, W. Quint, J. Walz, Y. Yamazaki, C. Smorra, S. Ulmer
Summary: The standard model of particle physics is incomplete in explaining the imbalance between matter and antimatter in the universe. This study focuses on investigating the fundamental properties of protons and antiprotons, specifically comparing their charge-to-mass ratios with high precision. The results provide insight into the standard model and improve the understanding of the properties of matter and antimatter.
Article
Physics, Multidisciplinary
C. Will, M. Bohman, T. Driscoll, M. Wiesinger, F. Abbass, M. J. Borchert, J. A. Devlin, S. Erlewein, M. Fleck, B. Latacz, R. Moller, A. Mooser, D. Popper, E. Wursten, K. Blaum, Y. Matsuda, C. Ospelkaus, W. Quint, J. Walz, C. Smorra, S. Ulmer
Summary: This article focuses on the remote sympathetic cooling of a single proton with laser-cooled Be-9(+) ions. Through analytical calculations and numerical simulations, two cooling schemes capable of achieving proton temperatures of about 10 mK in short cooling times are identified. These techniques allow for improved sampling rates and reduced systematic uncertainties in precision measurements based on trapped charged particles.
NEW JOURNAL OF PHYSICS
(2022)
Article
Quantum Science & Technology
M. Duwe, G. Zarantonello, N. Pulido-Mateo, H. Mendpara, L. Krinner, A. Bautista-Salvador, N. V. Vitanov, K. Hammerer, R. F. Werner, C. Ospelkaus
Summary: Microwave control of trapped ions enables high-fidelity two-qubit gates without errors induced by photon scattering. Recent developments show that amplitude modulation of the gate drive enhances the gate operation's resilience against noise. This study discusses a numerical optimization method for the microwave pulse envelope, resulting in gate pulses with noise resilience, faster operation, and high energy efficiency.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Instruments & Instrumentation
M. Schubert, L. Kilzer, T. Dubielzig, M. Schilling, C. Ospelkaus, B. Hampel
Summary: In this work, an RF resonator that actively matches the impedance for different ion traps is demonstrated. The active part of the matching circuit consists of a varactor diode array. The RF resonator is tested in a cryostat at room temperature and cryogenic temperatures, showing superior impedance matching.
REVIEW OF SCIENTIFIC INSTRUMENTS
(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
Optics
B. M. Latacz, B. P. Arndt, B. B. Bauer, J. A. Devlin, S. R. Erlewein, M. Fleck, J. I. Jaeger, M. Schiffelholz, G. Umbrazunas, E. J. Wursten, F. Abbass, P. Micke, D. Popper, M. Wiesinger, C. Will, H. Yildiz, K. Blaum, Y. Matsuda, A. Mooser, C. Ospelkaus, W. Quint, A. Soter, J. Walz, Y. Yamazaki, C. Smorra, S. Ulmer
Summary: The BASE collaboration at CERN's antiproton decelerator/ELENA facility has achieved ultra-high precision measurements of the fundamental properties of protons and antiprotons. Their measurements of the magnetic moments of protons and antiprotons have fractional uncertainties of 300 parts in a trillion and 1.5 parts in a billion, respectively, significantly improving the resolution of previous tests in this area. They have also compared the charge-to-mass ratios of antiprotons and protons with high precision and performed a differential matter/antimatter clock comparison test. Their measurements provide insights into CPT and Lorentz violation and the interaction between antimatter and dark matter.
EUROPEAN PHYSICAL JOURNAL D
(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, Software Engineering
Tobias Schmale, Bence Temesi, Alakesh Baishya, Nicolas Pulido-Mateo, Ludwig Krinner, Timko Dubielzig, Christian Ospelkaus, Hendrik Weimer, Daniel Borcherding
Summary: This study introduces a promising architecture for scaling up quantum computers based on trapped ions, known as Quantum Charged-Coupled Devices (QCCD), and presents the backend compiler phases needed for running quantum circuits on this architecture, along with strategies to solve optimization problems.
2022 IEEE INTERNATIONAL CONFERENCE ON QUANTUM SOFTWARE (IEEE QSW 2022)
(2022)
Article
Optics
J. Berrocal, E. Altozano, F. Dominguez, M. J. Gutierrez, J. Cerrillo, F. J. Fernandez, M. Block, C. Ospelkaus, D. Rodriguez
Summary: This paper presents a method for using two-ion crystals in a 7-tesla Penning trap for quantum metrology research. The experiment successfully forms the two-ion crystals and performs laser cooling to approach the quantum regime.
