Article
Multidisciplinary Sciences
Adam R. Mills, Charles R. Guinn, Michael J. Gullans, Anthony J. Sigillito, Mayer M. Feldman, Erik Nielsen, Jason R. Petta
Summary: Silicon spin qubits have the potential to become the dominant technology in the development of intermediate-scale quantum processors. However, there are still shortcomings in achieving high-fidelity state preparation and readout, as well as single- and two-qubit gate operations.
Article
Physics, Applied
T. J. Evans, W. Huang, J. Yoneda, R. Harper, T. Tanttu, K. W. Chan, F. E. Hudson, K. M. Itoh, A. Saraiva, C. H. Yang, A. S. Dzurak, S. D. Bartlett
Summary: Benchmarking and characterizing quantum states and logic gates are crucial in the development of quantum computing devices. This paper introduces a Bayesian approach called fast Bayesian tomography (FBT) for self-consistent process tomography and demonstrates its performance in characterizing a two-qubit gate set on a silicon-based spin qubit device.
PHYSICAL REVIEW APPLIED
(2022)
Article
Multidisciplinary Sciences
Albert Beardo, Miquel Lopez-Suarez, Luis Alberto Perez, Lluc Sendra, Maria Isabel Alonso, Claudio Melis, Javier Bafaluy, Juan Camacho, Luciano Colombo, Riccardo Rurali, Francesc Xavier Alvarez, Juan Sebastian Reparaz
Summary: High-frequency second sound in thermal transport has been demonstrated in bulk natural Ge between 7 K and room temperature by studying the phase lag of the thermal response under a harmonic high-frequency external thermal excitation. This opens up opportunities to investigate wave-like heat transport in almost any material and control heat through its oscillatory nature.
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
Chemistry, Physical
Yiming Zhang, Jing Liu, Wei Jin, Georgios Lefkidis, Wolfgang Huebner, Chun Li
Summary: This study proposes a design of two-qubit logic gates based on optically induced ultrafast spin dynamics, utilizing quantum chemical computations to determine the structure on Co4-GNF. Logical operations are achieved by spin-transfer and spin-flip processes between Co atoms on graphene nanoflakes.
Article
Quantum Science & Technology
Xiu Gu, Jorge Fernandez-Pendas, Pontus Vikstal, Tahereh Abad, Christopher Warren, Andreas Bengtsson, Giovanna Tancredi, Vitaly Shumeiko, Jonas Bylander, Goran Johansson, Anton Frisk Kockum
Summary: Near-term quantum computers are restricted to running low-depth quantum circuits due to the decoherence of qubits, limiting the types of quantum algorithms that can be implemented. By expanding the gate set to include multiqubit gates, it is possible to overcome these limitations and achieve gate fidelities above 99% in current quantum-computing platforms. Additionally, using simultaneous two-qubit gates allows for the swift creation of large entangled states like Dicke and Greenberger-Horne-Zeilinger states.
Article
Multidisciplinary Sciences
Nico W. Hendrickx, William I. L. Lawrie, Maximilian Russ, Floor van Riggelen, Sander L. de Snoo, Raymond N. Schouten, Amir Sammak, Giordano Scappucci, Menno Veldhorst
Summary: Research on building quantum circuits using advanced semiconductor manufacturing techniques has led to the demonstration of a four-qubit quantum processor based on hole spins in germanium quantum dots. All-electric qubit logic allows for freely programmable operations on multiple qubits, resulting in a compact and highly connected circuit. The results are a step towards quantum error correction and quantum simulation using quantum dots.
Article
Materials Science, Multidisciplinary
David W. Kanaar, Utkan Gungordu, J. P. Kestner
Summary: In this study, a deep neural network is utilized to optimize two-qubit gates against charge noise errors and crosstalk. The results show that this approach can effectively improve the accuracy of two-qubit gates in different scenarios.
Article
Quantum Science & Technology
Alberto Tosato, Beatrice Ferrari, Amir Sammak, Alexander R. Hamilton, Menno Veldhorst, Michele Virgilio, Giordano Scappucci
Summary: A hole bilayer in a strained germanium double quantum well was designed, fabricated, and studied. The magnetotransport characterization revealed two hole channels with high mobility and low percolation density. The interference patterns of the Landau fan diagram were used to determine the individual population of the channels. At a specific density, the system displayed resonance behavior with an observed anti-crossing of the bilayer subbands and an estimated symmetric-antisymmetric gap.
ADVANCED QUANTUM TECHNOLOGIES
(2022)
Article
Multidisciplinary Sciences
Ke Wang, Gang Xu, Fei Gao, He Liu, Rong-Long Ma, Xin Zhang, Zhanning Wang, Gang Cao, Ting Wang, Jian-Jun Zhang, Dimitrie Culcer, Xuedong Hu, Hong-Wen Jiang, Hai-Ou Li, Guang-Can Guo, Guo-Ping Guo
Summary: Hole-spin qubits in germanium show promise for rapid, all-electrical qubit control. The authors demonstrate ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire, with a record Rabi frequency exceeding 540 MHz. These results suggest the potential for ultrafast coherent control of hole spin qubits to meet the requirements for scalable quantum information processing.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Song Li, Gergo Thiering, Peter Udvarhelyi, Viktor Ivady, Adam Gali
Summary: Identifying and fabricating defect qubits in two-dimensional semiconductors is crucial for quantum information and sensing applications. Recent research has achieved the engineering of a single carbon defect in single layer tungsten disulphide with atomic precision, demonstrating its potential as a scalable qubit. By determining its electronic structure and optical properties, the authors establish this defect as a viable qubit candidate operating close to the telecom band.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Applied
Jian-Kun Li, Hong-Zhang Wang, Jie-Yin Zhang, Yuan-Jun Song, Zheng-Shan Guo, Cheng-Gang Yang, Xi Lin, Jian-Jun Zhang, Jian-Hao Chen, Tian Pei
Summary: We report a high sensitivity quantum capacitance measurement technique using an improved radio frequency superheterodyne bridge for investigating the electronic properties of Ge/SiGe 2D hole gas (2DHG) under low temperatures and a perpendicular magnetic field. Our results show a rapid decrease in quantum capacitance with a B-3 dependence at low fields, indicating a sudden change in chemical potential near the gate boundary at high frequencies, and a series of capacitance oscillations at high fields due to Landau quantization and Zeeman splitting of the Ge/SiGe 2DHG. Furthermore, we extracted the gate-dependent effective g factor under B-+/- from these measurements. This high-precision capacitance measurement technique provides insights into the physical properties of Ge/SiGe 2DHG.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Shihang Zhang, Yu He, Peihao Huang
Summary: Silicon-based spin qubits are attractive for quantum computing due to their long coherence time and compatibility with semiconductor fabrication. Recent studies have focused on hole spin qubits, which have the advantages of weak coupling to nuclear spin noise and strong spin-orbit coupling. However, there is limited research on hole spin qubits in a single acceptor, which only requires low density of metallic gates. This study investigates the tunability of electric dipole spin resonance (EDSR) of acceptor-based hole spin qubits with controllable strain, allowing for optimized operation performance and enhanced gate quality factors.
Article
Quantum Science & Technology
Donovan Buterakos, Sankar Das Sarma
Summary: Research shows that the presence of valley states in silicon quantum dots can lead to spin-valley entanglement, potentially affecting the fidelity of multiqubit systems.
Article
Quantum Science & Technology
T. Kobayashi, T. Nakajima, K. Takeda, A. Noiri, J. Yoneda, S. Tarucha
Summary: This article presents the active reset of a silicon spin qubit using feedback control, based on quantum non-demolition (QND) readout and hardware data processing. The incorporation of cumulative readout technique enhances the initialization fidelity and suggests a pathway towards fault-tolerant quantum computation. These results provide a practical approach to achieve high-fidelity qubit operations in realistic devices.
NPJ QUANTUM INFORMATION
(2023)
Article
Engineering, Electrical & Electronic
M. P. Stehno, N. W. Hendrickx, M. Snelder, T. Scholten, Y. K. Huang, M. S. Golden, A. Brinkman
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2017)
Article
Multidisciplinary Sciences
N. W. Hendrickx, D. P. Franke, A. Sammak, M. Kouwenhoven, D. Sabbagh, L. Yeoh, R. Li, M. L. Tagliaferri, M. Virgilio, G. Capellini, G. Scappucci, M. Veldhorst
NATURE COMMUNICATIONS
(2018)
Article
Chemistry, Multidisciplinary
Amir Sammak, Diego Sabbagh, Nico W. Hendrickx, Mario Lodari, Brian Paquelet Wuetz, Alberto Tosato, LaReine Yeoh, Monica Bollani, Michele Virgilio, Markus Andreas Schubert, Peter Zaumseil, Giovanni Capellini, Menno Veldhorst, Giordano Scappucci
ADVANCED FUNCTIONAL MATERIALS
(2019)
Article
Physics, Applied
W. I. L. Lawrie, H. G. J. Eenink, N. W. Hendrickx, J. M. Boter, L. Petit, S. Amitonov, M. Lodari, B. Paquelet Wuetz, C. Volk, S. G. J. Philips, G. Droulers, N. Kalhor, F. van Riggelen, D. Brousse, A. Sammak, L. M. K. Vandersypen, G. Scappucci, M. Veldhorst
APPLIED PHYSICS LETTERS
(2020)
Article
Multidisciplinary Sciences
L. Petit, H. G. J. Eenink, M. Russ, W. I. L. Lawrie, N. W. Hendrickx, S. G. J. Philips, J. S. Clarke, L. M. K. Vandersypen, M. Veldhorst
Article
Chemistry, Multidisciplinary
W. I. L. Lawrie, N. W. Hendrickx, F. van Riggelen, M. Russ, L. Petit, A. Sammak, G. Scappucci, M. Veldhorst
Article
Materials Science, Multidisciplinary
N. W. Hendrickx, M. L. Tagliaferri, M. Kouwenhoven, R. Li, D. P. Franke, A. Sammak, A. Brinkman, G. Scappucci, M. Veldhorst
Article
Materials Science, Multidisciplinary
J. C. C. Hwang, C. H. Yang, M. Veldhorst, N. Hendrickx, M. A. Fogarty, W. Huang, F. E. Hudson, A. Morello, A. S. Dzurak