Article
Multidisciplinary Sciences
C. D. Wilen, S. Abdullah, N. A. Kurinsky, C. Stanford, L. Cardani, G. D'Imperio, C. Tomei, L. Faoro, L. B. Ioffe, C. H. Liu, A. Opremcak, B. G. Christensen, J. L. DuBois, R. McDermott
Summary: The central challenge in building a quantum computer is the need for error correction, which requires accurate monitoring of errors and ensuring their lack of correlation. Encoding quantum information in entangled arrays of qubits can help achieve this goal.
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
Physics, Multidisciplinary
Zhongchu Ni, Sai Li, Libo Zhang, Ji Chu, Jingjing Niu, Tongxing Yan, Xiuhao Deng, Ling Hu, Jian Li, Youpeng Zhong, Song Liu, Fei Yan, Yuan Xu, Dapeng Yu
Summary: Researchers propose and demonstrate a method for eliminating unwanted ZZ interaction in superconducting qubit systems. By applying a weak microwave drive, ZZ interaction can be noninvasively cancelled, improving the quality of quantum operations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
V Iaia, J. Ku, A. Ballard, C. P. Larson, E. Yelton, C. H. Liu, S. Patel, R. McDermott, B. L. T. Plourde
Summary: Researchers achieve a suppression of correlated error rate by channeling high-energy particle impacts caused by background radiation away from the qubits via a thick metal layer at the bottom of the chip. They also use a pump-probe scheme to monitor the parity of quasiparticles on qubit chips and observe a significant reduction in correlated poisoning.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Particles & Fields
L. Cardani, I. Colantoni, A. Cruciani, F. De Dominicis, G. D'Imperio, M. Laubenstein, A. Mariani, L. Pagnanini, S. Pirro, C. Tomei, N. Casali, F. Ferroni, D. Frolov, L. Gironi, A. Grassellino, M. Junker, C. Kopas, E. Lachman, C. R. H. McRae, J. Mutus, M. Nastasi, D. P. Pappas, R. Pilipenko, M. Sisti, V. Pettinacci, A. Romanenko, D. Van Zanten, M. Vignati, J. D. Withrow, N. Z. Zhelev
Summary: Researchers discovered that radioactivity can cause decoherence and errors in the implementation of superconducting quantum processors. They measured the levels of radioactivity in a typical laboratory environment and in commonly used materials for superconducting qubits. Through simulation, they predicted the impact rate and energy release in qubit chips from different sources, and proposed strategies to mitigate these effects in a radio-pure environment.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Materials Science, Multidisciplinary
Nathan L. Foulk, Robert E. Throckmorton, S. Das Sarma
Summary: The research finds that randomness in dissipation parameter has little effect on the fidelity of SWAP gates in currently fabricated Si circuits, while gate timing error leads to an optimal value of the exchange coupling strength for SWAP gates, beyond which fidelity begins to decrease.
Article
Computer Science, Hardware & Architecture
Zeyu Mi, Zhi Guo, Fuqian Huang, Haibo Chen
Summary: The confidentiality of operating system kernel addresses is crucial for its security. Researchers have proposed techniques to defeat memory safety loopholes, but leakage can still occur. We developed Hawkeye, a static analysis tool that identifies kernel address leakages in normal data flows with minimum manual annotation and reduced resource and inspection time requirements. Hawkeye has uncovered numerous leakages in different kernel versions and discovered bugs in Linux and FreeBSD.
IEEE TRANSACTIONS ON DEPENDABLE AND SECURE COMPUTING
(2023)
Article
Physics, Applied
Arno Bargerbos, Lukas Johannes Splitthoff, Marta Pita-Vidal, Jaap J. Wesdorp, Yu Liu, Peter Krogstrup, Leo P. Kouwenhoven, Christian Kraglund Andersen, Lukas Grunhaupt
Summary: Quantum error correction is crucial for achieving fault-tolerant quantum computing, but existing schemes assume uncorrelated errors in space and time. However, in superconducting qubits, ionizing radiation violates this assumption and leads to correlated errors. To mitigate this, adding large volumes of normal or superconducting metal to the device can decrease the phonon energy below the superconducting gap of the qubits. In experiments with a nanowire-based transmon qubit device, we found that with a lower superconducting gap material, there was 2-5 times less degradation in qubit lifetimes and the undesired qubit state population was also reduced. The effectiveness of this protection was not limited by the size of the superconducting gap in the added metal. These findings provide a promising foundation for protecting superconducting-qubit processors against correlated errors from ionizing radiation.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Multidisciplinary
Michael T. Jones, Md Serajum Monir, Felix N. Krauth, Pascal Macha, Yu-Ling Hsueh, Angus Worrall, Joris G. Keizer, Ludwik Kranz, Samuel K. Gorman, Yousun Chung, Rajib Rahman, Michelle Y. Simmons
Summary: This study demonstrates a platform for quantum computing using phosphorus donor atoms in silicon. By adjusting the arrangement and spacing of the donor atoms, the speed and accuracy of qubit gates can be improved without affecting neighboring qubits. This approach provides a new pathway for achieving high fidelity and scalable quantum computing.
Article
Automation & Control Systems
Chi Wei, Shaobin Huang, Rongsheng Li, Ye Liu, Naiyu Yan
Summary: This paper proposes a fusion scheme to correct spelling errors in sentences, which utilizes a detection module, original input, and masked input to acquire comprehensive sentence semantic information, achieving superior performance on two benchmarks.
ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE
(2024)
Article
Materials Science, Multidisciplinary
Philipp M. Mutter, Guido Burkard
Summary: The study explores the impact of spin-orbit interaction on heavy holes confined in a double quantum dot in the presence of a magnetic field. Coupling between hole states of different spins can be canceled at certain detunings and tilting angles of the magnetic field, allowing for control over the system. In systems with strong spin-orbit interaction at weak magnetic fields, the choice of magnetic field can reduce leakage errors and provide reliable control over the qubit ground state.
Article
Physics, Multidisciplinary
J. F. Marques, H. Ali, B. M. Varbanov, M. Finkel, H. M. Veen, S. L. M. Van der Meer, S. Valles-Sanclemente, N. Muthusubramanian, M. Beekman, N. Haider, B. M. Terhal, L. DiCarlo
Summary: This study extends a quantum-hardware-efficient, all-microwave leakage reduction unit (LRU) to effectively reduce leakage in the second and third excited states of transmons, minimizing the loss of quantum states with minimal impact on the qubit subspace.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Xiao-Feng Shi
Summary: This paper presents a theory for cooling 87Sr nuclear-spin qubits in a weak magnetic field. The theory involves laser excitation of the 5s5p 3P1 state to a nearby state with mJ-dependent AC Stark shifts that are larger than the hyperfine interaction. This effectively suppresses nuclear-spin mixing caused by the hyperfine interaction. Sideband cooling via the AC Stark-shifted 3P1 state quenched by the clock state leads to nuclear-spin-preserving spontaneous emission back to the ground state. The theory is not only compatible with low magnetic fields but also applicable to nuclear-spin qubits defined by the two lowest Zeeman substates.
Article
Environmental Sciences
Chenyu Ge, Mengmeng Wang, Hongming Zhang, Huan Chen, Hongguang Sun, Yi Chang, Qinke Yang
Summary: The study introduced a method based on low-rank group-sparsity to handle mixed errors in digital elevation model data, utilizing group-sparse regularization and variational ideas. Experimental results demonstrated that this method outperformed other approaches in both visual and quantitative evaluations.
News Item
Optics
Hyunseok Jeong
Summary: A scheme for converting qubits between discrete and continuous variables opens up possibilities for more efficient quantum networks.
Article
Physics, Multidisciplinary
Tyler Keating, Charles H. Baldwin, Yuan-Yu Jau, Jongmin Lee, Grant W. Biedermann, Ivan H. Deutsch
PHYSICAL REVIEW LETTERS
(2016)
Article
Physics, Multidisciplinary
H. Sosa-Martinez, N. K. Lysne, C. H. Baldwin, A. Kalev, I. H. Deutsch, P. S. Jessen
PHYSICAL REVIEW LETTERS
(2017)
Article
Optics
Charles H. Baldwin, Amir Kalev, Ivan H. Deutsch
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
Quantum Science & Technology
Charles H. Baldwin, Karl Mayer, Natalie C. Brown, Ciaran Ryan-Anderson, David Hayes
Summary: The quantum volume test is a comprehensive benchmark for quantum computers, evaluating their sensitivity to factors such as qubit number and fidelity. This paper explores the test's design aspects, sensitivity to errors, and implications for quantum computers. It proposes a new confidence interval construction and an efficient algorithm for predicting performance goals. The findings provide insights into the practical and operational abilities of quantum computers, particularly in quantum error correction.
Article
Optics
J. P. Gaebler, C. H. Baldwin, S. A. Moses, J. M. Dreiling, C. Figgatt, M. Foss-Feig, D. Hayes, J. M. Pino
Summary: Midcircuit measurement and reset are crucial in quantum computation, but maintaining isolation of neighboring qubits while interacting with selected qubits poses a significant challenge. This study presents a technique using ion micromotion to reduce sources of decoherence significantly in trapped ion systems, demonstrating low crosstalk errors on nearby qubits during measurement and reset on select qubits using the Honeywell System Model H0.
Article
Optics
C. H. Baldwin, B. J. Bjork, M. Foss-Feig, J. P. Gaebler, D. Hayes, M. G. Kokish, C. Langer, J. A. Sedlacek, D. Stack, G. Vittorini
Summary: By combining the advantages of the Molmer-Sorensen gate and the light-shift gate, a technique has been developed to operate the light-shift gate directly on hyperfine clock states with high gate fidelity achieved through small detuning from optical transition. Further improvements in gate fidelity above 99.99% are suggested through theoretical modeling.
Article
Physics, Multidisciplinary
C. H. Baldwin, B. J. Bjork, J. P. Gaebler, D. Hayes, D. Stack
PHYSICAL REVIEW RESEARCH
(2020)
Article
Optics
Adam C. Keith, Charles H. Baldwin, Scott Glancy, E. Knill
Article
Optics
Charles H. Baldwin, Ivan H. Deutsch, Amir Kalev