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Preserving qubit coherence and maintaining high-fidelity qubit control under complex noise environment is an enduring challenge for scalable quantum computing. Here we demonstrate an addressable fault-tolerant single spin qubit with an…

High fidelity two-qubit gates are fundamental for scaling up the superconducting number. We use two qubits coupled via a frequency-tunable coupler which can adjust the coupling strength, and demonstrate the CZ gate using two different…

Entangling gates between neighboring physical qubits are essential for quantum error correction. Implementing them in an all-microwave manner simplifies signal routing and control apparatus of superconducting quantum processors. We propose…

Quantum Physics · Physics 2025-11-11 Shotaro Shirai , Shinichi Inoue , Shuhei Tamate , Rui Li , Yasunobu Nakamura , Atsushi Noguchi

We demonstrate a hardware-agnostic protocol for realizing fast, high-fidelity gates through dynamical decoupling (DD) pulse sequences applied to a central qubit coupled to target qubits. The target qubits are controlled by leveraging their…

Quantum Physics · Physics 2026-05-06 Lucas Tsunaki , Michael Dotan , Kseniia Volkova , Boris Naydenov

For the quantum error correction (QEC) and noisy intermediate-scale quantum (NISQ) algorithms to function with high efficiency, the raw fidelity of quantum logic gates on physical qubits needs to satisfy strict requirement. The neutral atom…

Quantum Physics · Physics 2025-06-02 Yuan Sun

We study controllable exchange coupling between two singlet-triplet qubits. We start from the original second quantized Hamiltonian of a quadruple quantum dot system and obtain the effective spin-spin interaction between the two qubits…

Mesoscale and Nanoscale Physics · Physics 2013-05-13 Rui Li , Xuedong Hu , J. Q. You

Contemporary quantum computers encode and process quantum information in binary qubits (d = 2). However, many architectures include higher energy levels that are left as unused computational resources. We demonstrate a superconducting…

Electron spins in semiconductors are promising qubits because their long coherence times enable nearly 10^9 coherent quantum gate operations. However, developing a scalable high-fidelity two-qubit gate remains challenging. Here, we…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 John M. Nichol , Lucas A. Orona , Shannon P. Harvey , Saeed Fallahi , Geoffrey C. Gardner , Michael J. Manfra , Amir Yacoby

A double-transmon coupler (DTC) enables a fast, high-fidelity CZ gate between two highly detuned, fixed-frequency transmon qubits. Moreover, a recently proposed capacitively shunted DTC (CSDTC) realizes a small residual ZZ interaction over…

Quantum Physics · Physics 2026-05-01 Shinichi Inoue , Rui Li , Kentaro Kubo , Yinghao Ho , Yasunobu Nakamura , Hayato Goto

Quantum computation based on nonadiabatic geometric phases has attracted a broad range of interests, due to its fast manipulation and inherent noise resistance. However, it is limited to some special evolution paths, and the gate-times are…

Quantum Physics · Physics 2021-11-29 Cheng-Yun Ding , Li-Na Ji , Tao Chen , Zheng-Yuan Xue

We present a method of implementing ultrafast two-qubit gates valid for the ultrastrong coupling (USC) and deep strong coupling (DSC) regimes of light-matter interaction, considering state-of-the-art circuit quantum electrodynamics (QED)…

Quantum Physics · Physics 2015-05-30 G. Romero , D. Ballester , Y. M. Wang , V. Scarani , E. Solano

We will present a few new generalizations of the multi-controlled X (MCX) gate that uses the quantum Fourier transform (QFT). Firstly, we will optimize QFT-MCX and prove that it is equivalent to a stair MCX gates array. This stair-wise…

Quantum Physics · Physics 2025-02-21 Vladimir V. Arsoski

We present a generalized electrostatic SWAP gate realized in a chain of two double quantum dots operated in the single-electron regime. Using a minimalist tight-binding model, we derive analytical results and corroborate them with numerical…

Mesoscale and Nanoscale Physics · Physics 2025-10-08 Krzysztof Pomorski , Eryk Halubek

We introduce a novel scheme that combines phonon-mediated quantum logic gates in trapped ions with the benefits of continuous dynamical decoupling. We demonstrate theoretically that a strong driving of the qubit decouples it from external…

Quantum Physics · Physics 2012-04-11 A. Bermudez , P. O. Schmidt , M. B. Plenio , A. Retzker

High-performance two-qubit gates have been reported with superconducting qubits coupled via a single-transmon coupler (STC). Most of them are implemented for qubits with a small detuning since reducing residual $ZZ$ coupling for highly…

Quantum Physics · Physics 2023-02-09 Kentaro Kubo , Hayato Goto

Centralized Multiport Networked Dynamic (CMND) systems have emerged as a key architecture with applications in several complex network systems, such as multilateral telerobotics and multi-agent control. These systems consist of a hub…

Robotics · Computer Science 2026-01-26 Xingyuan Zhou , Peter Paik , S. Farokh Atashzar

Implementation of high-fidelity two-qubit operations is a key ingredient for scalable quantum error correction. In superconducting qubit architectures tunable buses have been explored as a means to higher fidelity gates. However, these…

Scalable spin-based quantum computing demands precise and stable control of a large number of gate-defined quantum dots while minimizing wiring complexity and thermal load. Control architectures based on sample-and-hold (SH) multiplexing…

High-fidelity quantum gates are a cornerstone of any quantum computing and communications architecture. Realizing such control in the presence of realistic errors at the level required for beyond-threshold quantum error correction is a…

Quantum Physics · Physics 2025-12-08 E. Poem , M. I. Cohen , S. Blum , D. Minin , D. Korn , O. Heifler , S. Maayani , A. Hamo , I. Bayn , N. Bar-Gill , M. Tordjman

The fidelity of applications on near-term quantum computers is limited by hardware errors. In addition to errors that occur during gate and measurement operations, a qubit is susceptible to idling errors, which occur when the qubit is idle…

Quantum Physics · Physics 2021-09-14 Poulami Das , Swamit Tannu , Siddharth Dangwal , Moinuddin Qureshi