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We develop a theory for finding quantum error correction (QEC) procedures which are optimized for given noise channels. Our theory accounts for uncertainties in the noise channel, against which our QEC procedures are robust. We demonstrate…

Quantum Physics · Physics 2010-10-28 Soraya Taghavi , Robert L. Kosut , Daniel A. Lidar

Collective coherent noise poses challenges for fault-tolerant quantum error correction (FTQEC), as it falls outside the usual stochastic noise models. While constant excitation (CE) codes can naturally avoid coherent noise, a complete…

Quantum Physics · Physics 2025-07-15 Ching-Yi Lai , Pei-Hao Liou , Yingkai Ouyang

Channel capacities quantify the optimal rates of sending information reliably over noisy channels. Usually, the study of capacities assumes that the circuits which sender and receiver use for encoding and decoding consist of perfectly…

Quantum Physics · Physics 2024-04-15 Paula Belzig , Matthias Christandl , Alexander Müller-Hermes

We study the performance of quantum error correction (QEC) on a system undergoing open-system (OS) dynamics. The noise on the system originates from a joint quantum channel on the system-bath composite, a framework that includes and…

Quantum Physics · Physics 2018-08-09 Yink Loong Len , Hui Khoon Ng

Complex quantum systems and their various applications are susceptible to noise of coherent and incoherent nature. Characterization of noise and its sources is an open, key challenge in quantum technology applications, especially in terms…

Conventional computers have evolved to device components that demonstrate failure rates of 1e-17 or less, while current quantum computing devices typically exhibit error rates of 1e-2 or greater. This raises concerns about the reliability…

Quantum Physics · Physics 2022-11-02 Samudra Dasgupta , Travis S. Humble

When modeling the effects of noise on quantum circuits, one often makes the assumption that these effects can be accounted for by individual decoherence events following an otherwise noise-free gate. In this work, we address the validity of…

Quantum Physics · Physics 2023-12-19 Keith R. Fratus , Juha Leppäkangas , Michael Marthaler , Jan-Michael Reiner

We investigate the quantum correlations in an axially symmetric hybrid qubit-qutrit system subjected to different noisy environments. We first introduce a physical model and analyze its Hamiltonian structure, emphasizing the role of hybrid…

Quantum Physics · Physics 2026-01-01 M. Abdellaoui , N. -E. Abouelkhir , A. Slaoui , R. Ahl Laamara , S. Haddadi

Quantum computers are poised to radically outperform their classical counterparts by manipulating coherent quantum systems. A realistic quantum computer will experience errors due to the environment and imperfect control. When these errors…

Quantum Physics · Physics 2016-11-21 Joel J. Wallman , Joseph Emerson

Variational quantum algorithms are tailored to perform within the constraints of current quantum devices, yet they are limited by performance-degrading errors. In this study, we consider a noise model that reflects realistic gate errors…

Quantum error detection can produce unbiased expectation values that exponentially converge to noiseless results as the code distance is increased. Despite this, its performance as an error mitigation technique is relatively understudied on…

Quantum Physics · Physics 2026-05-05 Yanis Le Fur , Ethan Egger , Hong-Ye Hu , Vincent Russo , William J. Zeng , Ryan LaRose

Errors occurring on noisy hardware pose a key challenge to reliable quantum computing. Existing techniques such as error correction, mitigation, or suppression typically separate the error handling from the algorithm analysis and design. In…

Quantum Physics · Physics 2026-01-21 Julian Berberich , Tobias Fellner , Robert L. Kosut , Christian Holm

We investigate how noise impacts nonstabilizerness - a key resource for quantum advantage - in many-body qubit systems. While noise typically degrades quantum resources, we show that amplitude damping, a nonunital channel, can generate or…

Quantum Physics · Physics 2026-04-14 Fabian Ballar Trigueros , José Antonio Marín Guzmán

A Quantum Computer is a new type of computer which can solve problems such as factoring and database search very efficiently. The usefulness of a quantum computer is limited by the effect of two different types of errors, decoherence and…

Quantum Physics · Physics 2007-05-23 Kevin M. Obenland , Alvin M. Despain

Pre-fault tolerant quantum computers have already demonstrated the ability to estimate observable values accurately, at a scale beyond brute-force classical computation. This has been enabled by error mitigation techniques that often rely…

Decoherence in qubits, caused by their interaction with a noisy environment, poses a significant challenge to the development of reliable quantum processors. A prominent source of errors arises from noise in coupled ancillas, which can…

A quantum channel models the interaction between the system we are interested in and its environment. Such a model can capture the main features of the interaction but because of the complexity of the environment we can not assume that it…

Quantum Physics · Physics 2015-05-13 Gábor Balló , Péter Gurin

The central challenge in building a quantum computer is error correction. Unlike classical bits, which are susceptible to only one type of error, quantum bits ("qubits") are susceptible to two types of error, corresponding to flips of the…

Quantum error correction methods use processing power to combat noise. The noise level which can be tolerated in a fault-tolerant method is therefore a function of the computational resources available, especially the size of computer and…

Quantum Physics · Physics 2015-06-26 Andrew Steane

Quantum error correction and symmetry arise in many areas of physics, including many-body systems, metrology in the presence of noise, fault-tolerant computation, and holographic quantum gravity. Here we study the compatibility of these two…

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