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Fault-tolerant quantum computing typically requires the transpilation of arbitrary quantum circuits into a finite, universal gate set, such as Clifford+T. As a baseline, Diagonal approximation can be used for synthesizing single-qubit Pauli…

Quantum Physics · Physics 2026-05-12 Gilad Kishony , Avi Elazari , Ron Cohen , Lior Gazit

Near-term and early fault-tolerant quantum computing architectures are expected to exhibit highly non-uniform error rates. In particular, local operations within a chip can be substantially more reliable than operations connecting different…

Quantum Physics · Physics 2026-05-27 Elisa Bäumer Marty

Conventional approaches to fault-tolerant quantum computing realize logical circuits gate-by-gate, synthesizing each gate independently on one or more code blocks. This incurs excess overhead and doesn't leverage common structures in…

Quantum Physics · Physics 2026-02-02 Zhuangzhuang Chen , Jack Owen Weinberg , Narayanan Rengaswamy

We present a novel method for simulating the noisy behaviour of quantum computers, which allows to efficiently incorporate environmental effects in the driven evolution implementing the gates acting on the qubits. We show how to modify the…

Can near-term gate model based quantum processors offer quantum advantage for practical applications in the pre-fault tolerance noise regime? A class of algorithms which have shown some promise in this regard are the so-called…

Quantum Physics · Physics 2019-08-13 Guillaume Verdon , Michael Broughton , Jacob Biamonte

With rapid advancements in machine learning, first-order algorithms have emerged as the backbone of modern optimization techniques, owing to their computational efficiency and low memory requirements. Recently, the connection between…

Quantum Physics · Physics 2025-05-21 Jiaqi Leng , Bin Shi

Variational quantum algorithms constitute one of the most widespread methods for using current noisy quantum computers. However, it is unknown if these heuristic algorithms provide any quantum-computational speedup, although we cannot…

Quantum computing hardware is affected by quantum noise that undermine the quality of results of an executed quantum program. Amongst other quantum noises, coherent error that caused by parameter drifting and miscalibration, remains…

Hardware Architecture · Computer Science 2024-10-15 Xiangyu Ren , Junjie Wan , Zhiding Liang , Antonio Barbalace

Trapped-ion systems are a promising route toward the realization of both near-term and universal quantum computers. However, one of the pressing challenges is improving the fidelity of two-qubit entangling gates. These operations are often…

Quantum Physics · Physics 2024-12-24 Luke Ellert-Beck , Wenchao Ge

Quantum error correction is vital for implementing universal quantum computing. A key component is the encoding circuit that maps a product state of physical qubits into the encoded multipartite entangled logical state. Known methods are…

Quantum Physics · Physics 2021-04-07 Xiaosi Xu , Simon C. Benjamin , Xiao Yuan

We present a gradient-based optimal-control technique for open quantum systems that utilizes quantum trajectories to simulate the quantum dynamics during optimization. Using trajectories allows for optimizing open systems with less…

Quantum Physics · Physics 2019-06-03 Mohamed Abdelhafez , David I. Schuster , Jens Koch

With improved gate calibrations reducing unitary errors, we achieve a benchmarked single-qubit gate fidelity of 99.95% with superconducting qubits in a circuit quantum electrodynamics system. We present a method for distinguishing between…

Quantum Physics · Physics 2016-01-13 Sarah Sheldon , Lev S. Bishop , Easwar Magesan , Stefan Filipp , Jerry M. Chow , Jay M. Gambetta

I describe the use of techniques based on composite rotations to combat systematic errors in controlled phase gates, which form the basis of two qubit quantum logic gates. Although developed and described within the context of Nuclear…

Quantum Physics · Physics 2007-05-23 Jonathan A. Jones

Within a numerically exact simulation technique, the dissipative dynamics of a two-qubit architecture is considered in which each qubit couples to its individual noise source (reservoir). The goal is to reveal the role of subtle…

Quantum Physics · Physics 2026-04-14 Kiyoto Nakamura , Joachim Ankerhold

As the nascent field of quantum computing develops, an increasing number of quantum hardware modalities, such as superconducting electronic circuits, semiconducting spins, trapped ions, and neutral atoms, have become available for…

Quantum Physics · Physics 2023-01-30 Sebastian Brandhofer , Jinwoong Kim , Siyuan Niu , Nicholas T. Bronn

We experimentally investigate the viability of a variational quantum gate optimization protocol informed by the underlying physical Hamiltonian of fixed-frequency transmon qubits. The utility of the scheme is demonstrated through the…

Quantum Physics · Physics 2024-07-02 Sean Greenaway , Francesco Petiziol , Hongzheng Zhao , Florian Mintert

A well-known strategy to characterize multiparticle entanglement utilizes the notion of stochastic local operations and classical communication (SLOCC), but characterizing the resulting entanglement classes is difficult. Given a…

Quantum Physics · Physics 2018-02-05 Jiangwei Shang , Otfried Gühne

The ability to engineer high-fidelity gates on quantum processors in the presence of systematic errors remains the primary barrier to achieving quantum advantage. Quantum optimal control methods have proven effective in experimentally…

Quantum Physics · Physics 2021-03-30 Thomas Propson , Brian E. Jackson , Jens Koch , Zachary Manchester , David I. Schuster

Quantum simulation has shown great potential in many fields due to its powerful computational capabilities. However, the limited fidelity can lead to a severe limitation on the number of gate operations, which requires us to find optimized…

Quantum Physics · Physics 2021-09-20 Yi-Tong Zou , Yu-Jiao Bo , Ji-Chong Yang

Scalable characterization of quantum processors is crucial for mitigating noise and imperfections. While randomized measurement protocols enable efficient access to local observables, inferring a globally consistent description of…

Quantum Physics · Physics 2026-03-10 Zidu Liu , Dominik S. Wild