Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Bulletin of the American Physical Society

Maintaining Qubit Coherence in the face of Increased Superconducting Circuit Complexity

David J. Hover, Steve Weber, Danna Rosenberg, Gabriel Samach, Adam Sears, Jeffrey Birenbaum, Wayne H. Woods, Jonilyn Yoder, Livia M. Racz, Jamie Kerman, William D. Oliver

Published Mar 18, 2016• 0 citations
OpenAlex

Related papers

Enabling technologies for increased circuit complexity of high-coherence superconducting qubits: Part 2

David K. Kim, Jonilyn Yoder, Rabindra Nath Das +11 more

Bulletin of the American Physical Society•Mar 8, 2018•0 citations

Enabling technologies for increased circuit complexity of high-coherence superconducting qubits: Part 1

Jonilyn Yoder, David K. Kim, P. M. Baldo +12 more

Bulletin of the American Physical Society•Mar 8, 2018•0 citations

Engineering high-coherence superconducting qubits

Irfan A. Siddiqi

Nature Reviews Materials•Sep 23, 2021•312 citations

Simulating Quantum Chemical Dynamics with Improved Superconducting Qubits

A. Megrant

A quantum computer will potentially solve far-reaching problems which are currently intractable on any classical computer. Many technological obstacles have prevented the realization of a quantum computer, the main obstacle being decoherence, which is the loss of quantum information. Decoherence arises from the undesired interaction between qubits and their environment. Isolated qubits have better coherence but are more difficult to control. Superconducting qubits are a promising platform since their macroscopic size allows for easy control and coupling to other qubits. While the coherence of superconducting qubits has substantially improved over the past two decades, further improvements in coherence are required.We have repeatedly and reliably increased the coherence times of superconducting qubits. Currently decoherence in these devices is dominated by coupling to material defects. These defects are present in the dielectrics used to fabricate these devices or introduced during fabrication. Using simpler resonators as a testbed, we individually isolate, characterize, and then improve each step of the more complicated fabrication of superconducting qubits. We increased the quality factor of resonators by a factor of four by first identifying the surfaces and interfaces as a major source of loss and then by optimizing the substrate preparation. Furthermore, we measure and subsequently mitigate additional defect loss, which is dependent on the position of ground plane holes used to limit the loss from magnetic vortices. Implementing these improvements led to an increase of our qubit coherence times by more than an order of magnitude.The progress made in coherence while maintaining a high degree of connectivity and controllability has been directly used in more complex circuits. One such device is a fully connected three qubit ring with both tunable qubit frequencies and adjustable qubit-qubit couplings. The considerable level of control allows us to generate the quantum dynamics resulting from a collision between Na and He atoms by encoding the problem into a time-dependent multi-qubit interaction. We compute a scattering cross section by measuring the probability of exciting the Na atom over a wide range of collision parameters. The scattering cross-section shows that there is a velocity where the excitation probability is maximized, in agreement with scattering experiments.

•Jan 1, 2016•1 citation

Superconducting Qubits Are Getting Serious

Matthias Steffen

Superconducting quantum circuits based on Josephson junctions have made rapid progress in demonstrating quantum behavior and scalability.However, the future prospects ultimately depend upon the intrinsic coherence of Josephson junctions, and whether superconducting qubits can be adequately isolated from their environment.We introduce a new architecture for superconducting quantum circuits employing a three-dimensional resonator that suppresses qubit decoherence while maintaining sufficient coupling to the control signal.With the new architecture, we demonstrate that Josephson junction qubits are highly coherent, with T 2 $ 10 to 20 s without the use of spin echo, and highly stable, showing no evidence for 1=f critical current noise.These results suggest that the overall quality of Josephson junctions in these qubits will allow error rates of a few 10 À4 , approaching the error correction threshold.

Physics•Dec 5, 2011•16 citations

Towards long coherence superconducting qubits

Matthias Steffen, Antonio D. Corcoles, Jerry M. Chow +8 more

Bulletin of the American Physical Society•Mar 23, 2011•0 citations
A quantum computer will potentially solve far-reaching problems which are currently intractable on any classical computer. Many technological obstacles have prevented the realization of a quantum computer, the main obstacle being decoherence, which is the loss of quantum information. Decoherence arises from the undesired interaction between qubits and their environment. Isolated qubits have better coherence but are more difficult to control. Superconducting qubits are a promising platform since their macroscopic size allows for easy control and coupling to other qubits. While the coherence of superconducting qubits has substantially improved over the past two decades, further improvements in coherence are required.We have repeatedly and reliably increased the coherence times of superconducting qubits. Currently decoherence in these devices is dominated by coupling to material defects. These defects are present in the dielectrics used to fabricate these devices or introduced during fabrication. Using simpler resonators as a testbed, we individually isolate, characterize, and then improve each step of the more complicated fabrication of superconducting qubits. We increased the quality factor of resonators by a factor of four by first identifying the surfaces and interfaces as a major source of loss and then by optimizing the substrate preparation. Furthermore, we measure and subsequently mitigate additional defect loss, which is dependent on the position of ground plane holes used to limit the loss from magnetic vortices. Implementing these improvements led to an increase of our qubit coherence times by more than an order of magnitude.The progress made in coherence while maintaining a high degree of connectivity and controllability has been directly used in more complex circuits. One such device is a fully connected three qubit ring with both tunable qubit frequencies and adjustable qubit-qubit couplings. The considerable level of control allows us to generate the quantum dynamics resulting from a collision between Na and He atoms by encoding the problem into a time-dependent multi-qubit interaction. We compute a scattering cross section by measuring the probability of exciting the Na atom over a wide range of collision parameters. The scattering cross-section shows that there is a velocity where the excitation probability is maximized, in agreement with scattering experiments.
Superconducting quantum circuits based on Josephson junctions have made rapid progress in demonstrating quantum behavior and scalability.However, the future prospects ultimately depend upon the intrinsic coherence of Josephson junctions, and whether superconducting qubits can be adequately isolated from their environment.We introduce a new architecture for superconducting quantum circuits employing a three-dimensional resonator that suppresses qubit decoherence while maintaining sufficient coupling to the control signal.With the new architecture, we demonstrate that Josephson junction qubits are highly coherent, with T 2 $ 10 to 20 s without the use of spin echo, and highly stable, showing no evidence for 1=f critical current noise.These results suggest that the overall quality of Josephson junctions in these qubits will allow error rates of a few 10 À4 , approaching the error correction threshold.