Article
Optics
Fu-Quan Dou, Fang-Mei Yang
Summary: In this paper, an implementation scheme of a quantum battery (QB) based on a superconducting circuit is proposed. The QB consists of N coupled transmon qubits and a one-dimensional transmission line resonator. The Hamiltonian of the QB system is derived and its charging performance is investigated by considering three decay channels. It is found that the presence of decay channels suppresses the high oscillation of the energy storage process, leading to a stable and powerful QB.
Article
Physics, Multidisciplinary
Marta Pita-Vidal, Arno Bargerbos, Rok Zitko, Lukas J. Splitthoff, Lukas Grunhaupt, Jaap J. Wesdorp, Yu Liu, Leo P. Kouwenhoven, Ramon Aguado, Bernard van Heck, Angela Kou, Christian Kraglund Andersen
Summary: Spin qubits in semiconductors are a promising platform for scalable quantum computing devices, but achieving multiqubit interactions over extended distances is challenging. Superconducting spin qubits encoded in Andreev levels provide an alternative with intrinsic spin-supercurrent coupling. This study demonstrates an electrostatically defined quantum dot Josephson junction with a spin-split doublet ground state, allowing for qubit manipulation and investigating the qubit performance using direct spin manipulation. Coupling the Andreev spin qubit with a superconducting transmon qubit shows strong coherent qubit-qubit coupling, a crucial step towards a hybrid architecture combining the advantages of both superconducting and semiconductor qubits.
Article
Physics, Applied
A. Kringhoj, T. W. Larsen, O. Erlandsson, W. Uilhoorn, J. G. Kroll, M. Hesselberg, R. P. G. McNeil, P. Krogstrup, L. Casparis, C. M. Marcus, K. D. Petersson
Summary: The study introduces a novel hybrid semiconductor-based superconducting qubit device that maintains coherence at high magnetic fields up to 1 Tesla. The qubit transition frequency shows periodic oscillations with the magnetic field, indicating interference effects due to magnetic flux threading the proximitized semiconductor nanowire junction. With the revival of induced superconductivity, additional coherent modes emerge at high magnetic fields, attributed to the interaction between the qubit and low-energy Andreev states.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Applied
Xingyu Wei, Junliang Jiang, Wenqu Xu, Tingting Guo, Kaixuan Zhang, Zishuo Li, Tianshi Zhou, Yifan Sheng, Chunhai Cao, Guozhu Sun, Peiheng Wu
Summary: We have designed and fabricated a compact superconducting qubit circuit using a nanothick NbN film on a high-resistivity silicon substrate. This circuit carries seven transmon qubits and has a much smaller size in the readout circuit compared to conventional superconducting qubit circuits. The transmons were measured and characterized in terms of frequency and time domains with different flux bias, and the transition frequency f01 was adjustable within the range of several GHz. The use of nanothick materials with high kinetic inductance in qubit circuits shows promising potential for quantum circuit integration.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Yuqian Dong, Yong Li, Wen Zheng, Yu Zhang, Zhuang Ma, Xinsheng Tan, Yang Yu
Summary: Quasiparticles near Josephson junctions in superconducting qubits are known to be a significant source of decoherence. We characterized the diffusion feature of quasiparticles in a quantum chip by measuring the energy relaxation time and residual excited-state population of a transmon qubit. Using the extracted transition rates, we phenomenologically modeled the quasiparticle diffusion in a superconducting circuit that contained both low-energy quasiparticles and hot nonequilibrium quasiparticles.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Seong Hyeon Park, Jeseok Bang, Soobin An, Seungyong Hahn
Summary: Superconducting quantum bits are seen as promising candidates for quantum information processing platforms, requiring scalable designs and long qubit lifetimes for practical quantum computing devices. This paper presents simulation results of a hexagonal transmon qubit in a superconducting coplanar waveguide resonator, evaluating its performance in a practical sense with finite-element method simulations considering dielectric and TLS losses. Key parameters of qubits in superconducting circuits are estimated using the black-box quantization method or solving cQED, suggesting geometric features and key parameters for typical quantum information processing applications.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Quantum Science & Technology
Aravind Plathanam Babu, Jani Tuorila, Tapio Ala-Nissila
Summary: Superconducting Josephson junction qubits are key in many applications, such as scalable quantum computers and thermal devices. Theoretical modeling typically uses the two-level approximation, but accurately capturing system dynamics requires considering higher excited states beyond this framework. This study explores the dynamics and control of a superconducting transmon, highlighting the impact of state leakage and the effectiveness of derivative removal adiabatic gates (DRAG) control in mitigating leakage errors.
NPJ QUANTUM INFORMATION
(2021)
Article
Physics, Applied
Martin Sandberg, Vivekananda P. Adiga, Markus Brink, Cihan Kurter, Conal Murray, Marinus Hopstaken, John Bruley, Jason S. Orcutt, Hanhee Paik
Summary: Silicon-germanium (SiGe) is a versatile material with applications in superconducting quantum computing. By fabricating transmon quantum bits on SiGe layers and studying microwave loss properties at cryogenic temperatures, we achieved high quality factor Q values, confirming compatibility with state-of-the-art superconducting quantum circuits.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
Hayato Goto
Summary: This article introduces a tunable coupler called a double-transmon coupler, which achieves fast high-fidelity two-qubit gates by controlling the magnetic flux and avoids residual coupling during idle time. This approach offers an alternative solution for improving the performance of superconducting quantum computers.
PHYSICAL REVIEW APPLIED
(2022)
Article
Materials Science, Multidisciplinary
Halima Giovanna Ahmad, Valentina Brosco, Alessandro Miano, Luigi Di Palma, Marco Arzeo, Domenico Montemurro, Procolo Lucignano, Giovanni Piero Pepe, Francesco Tafuri, Rosario Fazio, Davide Massarotti
Summary: This paper proposes a method to realize a hybrid superconducting qubit using currently available tunnel ferromagnetic Josephson junctions, utilizing magnetic field pulses to tune the qubit frequency. It discusses the coupling to a readout resonator and the impact of magnetic fluctuations, and suggests the possibility of using the qubit as a noise detector to investigate the interplay of magnetism and superconductivity.
Article
Physics, Applied
Kentaro Kubo, Hayato Goto
Summary: High-performance parametric gates for highly detuned fixed-frequency qubits are demonstrated using a tunable coupler called a double-transmon coupler (DTC). By applying ac and dc flux pulses, maximally entangling universal gates (iSWAP) and CZ gates can be achieved with high fidelity and short gate times. The flexibility and feasible settings of the DTC make it a promising candidate for realizing high-performance quantum computers.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Tanmoy Bera, Sourav Majumder, Sudhir Kumar Sahu, Vibhor Singh
Summary: Researchers have demonstrated a hybrid device incorporating a superconducting transmon qubit and a mechanical resonator coupled using magnetic-flux. They showed a high vacuum electromechanical coupling rate and the enhancement of electromechanical coupling by tuning the qubit position, while observing specific interference features.
COMMUNICATIONS PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Yanshu Guo, Qichun Liu, Yaoyu Li, Wenqiang Huang, Tian Tian, Siqi Zhang, Nan Wu, Songyao Tan, Ning Deng, Zhihua Wang, Hanjun Jiang, Tiefu Li, Yuanjin Zheng
Summary: This article presents a cryogenic transmon qubit state controller integrated circuit for superconducting quantum computing applications. The controller uses a polar-modulation-based XY-path driver and a current-steering digital-to-analog converter (DAC)-based Z-path driver to control a qubit. Experimental results demonstrate that the controller performs well at a temperature of 3.5 K.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2023)
Article
Physics, Multidisciplinary
Syeda Aliya Batool, Sajid Rahmatullah, Sajid Qamar
Summary: We propose a scheme to enhance the electromagnetically induced acoustic transparency (EIAT) in a superconducting transmon circuit. By utilizing an additional microwave field, we increase the coherence in the second excited state, leading to amplification in transmission and a reduction in corresponding group velocity.
Article
Quantum Science & Technology
Chenlu Wang, Xuegang Li, Huikai Xu, Zhiyuan Li, Junhua Wang, Zhen Yang, Zhenyu Mi, Xuehui Liang, Tang Su, Chuhong Yang, Guangyue Wang, Wenyan Wang, Yongchao Li, Mo Chen, Chengyao Li, Kehuan Linghu, Jiaxiu Han, Yingshan Zhang, Yulong Feng, Yu Song, Teng Ma, Jingning Zhang, Ruixia Wang, Peng Zhao, Weiyang Liu, Guangming Xue, Yirong Jin, Haifeng Yu
Summary: A breakthrough in fabricating a long lifetime transmon qubit was reported, using tantalum films as the base superconductor with a dry etching process. The transmon qubits achieved a best T-1 lifetime of 503 μs, outperforming those fabricated with niobium and aluminum. The stable and highly anisotropic dry etching process of tantalum film shows promise for fabricating medium- or large-scale superconducting quantum circuits with longer lifetimes, meeting the requirements for practical quantum computers.
NPJ QUANTUM INFORMATION
(2022)