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Related papers: Exponentially robust non-Clifford gate in a driven…

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We show how combining a discrete symmetry with topological Hilbert space fragmentation can give rise to exponentially many topologically stable qubits protected by a single discrete symmetry. We illustrate this explicitly with the example…

Quantum Physics · Physics 2025-12-24 Thomas Iadecola , Rahul Nandkishore

We construct a minimal robust controlled-NOT gate with an Ising-type interaction by which elementary two-qubit gates are implemented. It is robust against inaccuracy of the coupling strength and the obtained quantum circuits are constructed…

Quantum Physics · Physics 2013-02-20 Tsubasa Ichikawa , Utkan Güngördü , Masamitsu Bando , Yasushi Kondo , Mikio Nakahara

Superconducting qubits with in-situ tunable properties are important for constructing a quantum computer. Qubit tunability, however, often comes at the expense of increased noise sensitivity. Here, we propose a flux-tunable superconducting…

Quantum Physics · Physics 2017-08-09 Eyob A. Sete , Matthew Reagor , Nicolas Didier , Chad T. Rigetti

Quantum computers are expected to bring drastic acceleration to several computing tasks against classical computers. Noisy intermediate-scale quantum (NISQ) devices, which have tens to hundreds of noisy physical qubits, are gradually…

Quantum Physics · Physics 2024-08-28 Yutaro Akahoshi , Kazunori Maruyama , Hirotaka Oshima , Shintaro Sato , Keisuke Fujii

Explicit controlled-NOT gate sequences between two qubits of different types are presented in view of applications for large-scale quantum computation. Here, the building blocks for such composite systems are qubits based on the…

Quantum Physics · Physics 2019-11-14 E. Ferraro , M. Fanciulli , M. De Michielis

Parasitic two-level-system (TLS) defects limit the stability and performance of solid-state quantum processors. Their interaction with a qubit can cause discrete, stochastic shifts of the qubit frequency, making the qubit bistable. We…

Ultracold trapped atomic ions excited into highly energetic Rydberg states constitute a promising platform for scalable quantum information processing. Elementary building blocks for such tasks are high-fidelity and sufficiently fast…

Hybrid semiconductor-superconductor qubits have recently emerged as a promising alternative to traditional platforms, combining material advantages with device-level tunability. A defining feature is their gate-tunable Josephson coupling,…

We show that states obtained from deep random Clifford circuits doped with non-Clifford phase gates (including T-gates and $\sqrt{\mathrm{T}}$-gates) can be disentangled completely, provided the number of non-Clifford gates is smaller or…

Quantum Physics · Physics 2026-01-08 Gerald E. Fux , Benjamin Béri , Rosario Fazio , Emanuele Tirrito

One of the main challenges in building a quantum processor is to characterize the environmental noise. Noise characterization can be achieved by exploiting different techniques, such as randomization where several sequences of random…

Quantum Physics · Physics 2020-11-04 Elena Ferraro , Marco De Michielis

Quantum gates, which are the essential building blocks of quantum computers, are very fragile. Thus, to realize robust quantum gates with high fidelity is the ultimate goal of quantum manipulation. Here, we propose a nonadiabatic geometric…

Quantum Physics · Physics 2020-07-15 Jing Xu , Sai Li , Tao Chen , Zheng-Yuan Xue

We present a new experimental protocol for performing universal gates in a register of superconducting qubits coupled by fixed on-chip linear reactances. The qubits have fixed, detuned Larmor frequencies and can remain, during the entire…

Quantum Physics · Physics 2009-11-10 Chad Rigetti , Michel Devoret

The design of coupler-based superconducting two-qubit gates simplifies circuit layout and alleviate frequency crowding, thereby enhancing the scalability and flexibility of quantum chips. However, in such architectures, a trade-off often…

Quantum Physics · Physics 2026-04-13 Bo-Xun Deng , Jia-Qi Hu , Cheng-Yun Ding , Zheng-Yuan Xue , Tao Chen

Geometric gates that use the global property of the geometric phase is believed to be a powerful tool to realize fault-tolerant quantum computation. However, for singlet-triplet qubits in semiconductor quantum dot, the low Rabi frequency of…

Quantum Physics · Physics 2022-03-23 Mei-Ya Chen , Chengxian Zhang , Zheng-Yuan Xue

Inductively shunted superconducting qubits, such as the unimon qubit, combine high anharmonicity with protection from low-frequency charge noise, positioning them as promising candidates for the implementation of fault-tolerant…

Quantum Physics · Physics 2025-07-29 Rostislav Duda , Eric Hyyppä , Olli Mukkula , Vasilii Vadimov , Mikko Möttönen

We exhibit nontrivial transversal logical multi-controlled-$Z$ gates on $[\![N,\Theta(N),\tilde\Theta(N)]\!]$ quantum low-density parity-check codes and $[\![N,\Theta(N),\tilde\Theta(N)]\!]$ quantum locally testable codes with soundness…

Quantum Physics · Physics 2026-04-03 Yiming Li , Zimu Li , Zi-Wen Liu

Dephasing -- phase randomization of a quantum superposition state -- is a major obstacle for the realization of high fidelity quantum logic operations. Here, we implement a two-qubit Controlled-NOT gate using dynamical decoupling (DD),…

Quantum Physics · Physics 2013-07-17 Ch. Piltz , B. Scharfenberger , A. Khromova , A. F. Varón , Ch. Wunderlich

We study the realization of a Toffoli gate with superconducting qubits in a circuit-QED setup using quantum-control methods. Starting with optimized piecewise-constant control fields acting on all qubits and typical strengths of XY-type…

Quantum Physics · Physics 2012-02-14 Vladimir M. Stojanovic , A. Fedorov , A. Wallraff , C. Bruder

Capacitively coupled semiconductor spin qubits hold promise as the building blocks of a scalable quantum computing architecture with long-range coupling between distant qubits. However, the two-qubit gate fidelities achieved in experiments…

Mesoscale and Nanoscale Physics · Physics 2015-10-29 Xin Wang , Edwin Barnes , S. Das Sarma

We proposed a new geometric quantum computation (GQC) scheme, called Floquet GQC (FGQC), where error-resilient geometric gates based on periodically driven two-level systems can be constructed via a new non-Abelian geometric phase proposed…

Quantum Physics · Physics 2023-11-23 Yuan-Sheng Wang , Bao-Jie Liu , Shi-Lei Su , Man-Hong Yung