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Related papers: Parameter optimization for the unimon qubit

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Gate-based quantum computers typically encode and process information in two-dimensional units called qubits. Using $d$-dimensional qudits instead may offer intrinsic advantages, including more efficient circuit synthesis, problem-tailored…

Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale superconductor-based quantum computing due to their better coherence and larger anharmonicity. A major challenge for multi-qubit…

The transmon, known for its fast operation time and the coherence time of tens of microseconds, is the most commonly used qubit for superconducting quantum processors. However, it is still necessary to enhance the coherence time and the…

Quantum Physics · Physics 2025-04-01 Jeongsoo Kang , Younghun Kwon

Gate-tunable transmon qubits are based on quantum conductors used as weak links within hybrid Josephson junctions. These gatemons have been implemented in just a handful of systems, all relying on extended conductors, namely epitaxial…

Mesoscale and Nanoscale Physics · Physics 2025-08-29 H. Riechert , S. Annabi , A. Peugeot , H. Duprez , M. Hantute , K. Watanabe , T. Taniguchi , E. Arrighi , J. Griesmar , J. -D. Pillet , L. Bretheau

We propose an optimal set of quantum gates for a singlet-triplet qubit in a double quantum dot with two electrons utilizing the $S$-$T_-$ subspace. Qubit rotations are driven by the applied magnetic field and an orthogonal field gradient…

Mesoscale and Nanoscale Physics · Physics 2015-07-20 Clement H. Wong , M. A. Eriksson , S. N. Coppersmith , Mark Friesen

We develop a Hamiltonian switching ansatz for bipartite control that is inspired by the Quantum Approximate Optimization Algorithm (QAOA), to mitigate environmental noise on qubits. We illustrate the approach with application to the…

Quantum Physics · Physics 2024-03-20 Zhibo Yang , Robert L. Kosut , K. Birgitta Whaley

The superconducting fluxonium qubit has a great potential for high-fidelity quantum gates with its long coherence times and strong anharmonicity at the half flux quantum sweet spot. However, current implementations of two-qubit gates…

As quantum circuits become more integrated and complex, additional error sources that were previously insignificant start to emerge. Consequently, the fidelity of quantum gates benchmarked under pristine conditions falls short of predicting…

Superconducting qubits are among the most promising platforms for building a quantum computer. However, individual qubit coherence times are not far past the scalability threshold for quantum error correction, meaning that millions of…

Quantum Physics · Physics 2016-04-20 Eliot Kapit

We analyze the accuracy of quantum phase gates acting on "0-$\pi$ qubits" in superconducting circuits, where the gates are protected against thermal and Hamiltonian noise by continuous-variable quantum error-correcting codes. The gates are…

Quantum Physics · Physics 2020-07-24 Peter Brooks , Alexei Kitaev , John Preskill

Semiconductor spin qubits demonstrated single-qubit gates with fidelities up to $99.9\%$ benchmarked in the single-qubit subspace. However, tomographic characterizations reveals non-negligible crosstalk errors in a larger space.…

Scalable superconducting quantum processors require balancing critical constraints in coherence, control complexity, and spectral crowding. Fixed-frequency architectures suppress flux noise and simplify control via all-microwave operations…

Quantum Physics · Physics 2025-10-17 Kui Zhao , Wei-Guo Ma , Ziting Wang , Hao Li , Kaixuan Huang , Yun-Hao Shi , Kai Xu , Heng Fan

Realizing individual control on single qubits in a spin-based quantum register is an ever-increasing challenge due to the close proximity of the qubits resonance frequencies. Current schemes typically suffer from an inherent trade-off…

Quantum Physics · Physics 2021-01-04 Jonatan Zimmermann , Paz London , Yaniv Yirmiyahu , Fedor Jelezko , Aharon Blank , David Gershoni

A two-qubit controlled-NOT (CNOT) gate, realized by a controlled-phase (C-phase) gate combined with single-qubit gates, has been experimentally implemented recently for quantum-dot spin qubits in isotopically enriched silicon, a promising…

Quantum Physics · Physics 2019-04-05 Chia-Hsien Huang , C. H. Yang , Chien-Chang Chen , A. S. Dzurak , Hsi-Sheng Goan

Recently, several groups have demonstrated two-qubit gate fidelities in semiconductor spin qubit systems above 99%. Achieving this regime of fault-tolerant compatible high fidelities is nontrivial and requires exquisite stability and…

Quantum computing promises significant speed-up for certain types of computational problems. However, robust implementations of semiconducting qubits must overcome the effects of charge noise that currently limit coherence during gate…

Quantum Physics · Physics 2017-07-12 Mark Friesen , Joydip Ghosh , M. A. Eriksson , S. N. Coppersmith

While the accuracy of qubit operations has been greatly improved in the last decade, further development is demanded to achieve the ultimate goal: a fault-tolerant quantum computer that can solve real-world problems more efficiently than…

Quantum Physics · Physics 2024-08-29 Kiyoto Nakamura , Joachim Ankerhold

High-fidelity single- and two-qubit gates are essential building blocks for a fault-tolerant quantum computer. While there has been much progress in suppressing single-qubit gate errors in superconducting qubit systems, two-qubit gates…

Quantum computation requires the precise control of the evolution of a quantum system, typically through application of discrete quantum logic gates on a set of qubits. Here, we use the cross-resonance interaction to implement a gate…

Developing optimal strategies to calibrate quantum processors for high-fidelity operation is one of the outstanding challenges in quantum computing today. Here, we demonstrate multiple examples of high-fidelity operations achieved using a…