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We suggest and demonstrate a protocol which suppresses dephasing due to the low-frequency noise by qubit motion, i.e., transfer of the logical qubit of information in a system of $n \geq 2$ physical qubits. The protocol requires only the…

Mesoscale and Nanoscale Physics · Physics 2016-01-13 D. V. Averin , K. Xu , Y. P. Zhong , C. Song , H. Wang , Siyuan Han

Superconducting qubits are a promising platform for building fault-tolerant quantum computers, with recent achievement showing the suppression of logical error with increasing code size. However, leakage into non-computational states, a…

We investigate the performance of dynamical decoupling methods at suppressing electron spin decoherence from a low-temperature nuclear spin reservoir in a quantum dot. The controlled dynamics is studied through exact numerical simulation,…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Wenxian Zhang , V. V. Dobrovitski , Lea F. Santos , Lorenza Viola , B. N. Harmon

In this paper, we propose a scheme to eliminate the influence of noises on system dynamics, by means of a sequential unsharp measurements and unitary feedback operations. The unsharp measurements are carried out periodically during system…

Quantum Physics · Physics 2018-09-19 Du Ran , Ye-Hong Chen , Zhi-Cheng Shi , Zhen-Biao Yang , Jie Song , Yan Xia

We employ pulse shaping to abate single-qubit gate errors arising from the weak anharmonicity of transmon superconducting qubits. By applying shaped pulses to both quadratures of rotation, a phase error induced by the presence of higher…

Mesoscale and Nanoscale Physics · Physics 2012-03-15 J. M. Chow , L. DiCarlo , J. M. Gambetta , F. Motzoi , L. Frunzio , S. M. Girvin , R. J. Schoelkopf

A major goal of developing high-precision control of many-body quantum systems is to realise their potential as quantum computers. Probably the most significant obstacle in this direction is the problem of "decoherence": the extreme…

Probabilistic error cancellation is a quantum error mitigation technique capable of producing unbiased computation results but requires an accurate error model. Constructing this model involves estimating a set of parameters, which, in the…

Quantum Physics · Physics 2026-01-12 Haipeng Xie , Nobuyuki Yoshioka , Kento Tsubouchi , Ying Li

Quantum error correction is a key challenge for the development of practical quantum computers, a direction in which significant experimental progress has been made in recent years. In solid-state qubits, one of the leading information loss…

Quantum Physics · Physics 2024-07-19 Dávid Pataki , Áron Márton , János K. Asbóth , András Pályi

Quantum metrology with entangled states in realistic noisy environments always suffers from decoherence. Therefore, the measurement precision is greatly reduced. Here we applied the dynamical decoupling method to protect the $N$-qubit…

Quantum Physics · Physics 2016-12-21 Yang Dong , Xiang-Dong Chen , Guang-Can Guo , Fang-Wen Sun

Quantum computing with qudits is an emerging approach that exploits a larger, more-connected computational space, providing advantages for many applications, including quantum simulation and quantum error correction. Nonetheless, qudits are…

To make arbitrarily accurate quantum computation possible, practical realization of quantum computers will require suppressing noise in quantum memory and gate operations to make it below a threshold value. A scheme based on realistic…

Quantum Physics · Physics 2007-05-23 Lu-Ming Duan , Guang-Can Guo

Quantum state purification is the functionality that, given multiple copies of an unknown state, outputs a state with increased purity. This will be an essential building block for near- and middle-term quantum ecosystems before the…

Quantum Physics · Physics 2024-06-14 Bo Yang , Elham Kashefi , Dominik Leichtle , Harold Ollivier

Dynamical decoupling can enforce a symmetry on the dynamics of an open quantum system. Here we develop an efficient dynamical-decoupling-based strategy to create the decoherence-free subspaces (DFSs) for a set of qubits by optimally…

Quantum Physics · Physics 2019-04-17 Jiang Zhang , Zheng-Yang Zhou , Lian-Ao Wu , J. Q. You

Noise in quantum hardware remains the biggest roadblock for the implementation of quantum computers. To fight the noise in the practical application of near-term quantum computers, instead of relying on quantum error correction which…

Quantum Physics · Physics 2021-10-14 Zhenyu Cai

We demonstrate that the performance of quantum error correction can be improved with noise-aware decoders that are calibrated to the likelihood of physical error configurations in a device. We show that noise-aware decoding increases the…

Quantum Physics · Physics 2025-04-02 Evan T. Hockings , Andrew C. Doherty , Robin Harper

Decoherence is a major challenge for quantum technologies. A way to mitigate its negative impact is by employing quantum optimal control. The decoherence dynamics varies significantly based on the characteristics of the surrounding…

The development of efficient algorithms that generate robust quantum controls is crucial for the realization of quantum technologies. The commonly used gradient-based optimization algorithms are limited by their sensitivity to the initial…

Quantum Physics · Physics 2021-12-03 M. Harshanth Ram , V. R. Krithika , Priya Batra , T. S. Mahesh

Superconducting circuits are a leading platform for quantum computing. However, their coherence times are still limited and exhibit temporal fluctuations. Those phenomena are often attributed to the coupling between qubits and material…

Quantum Physics · Physics 2022-10-13 Xinyuan You , Ziwen Huang , Ugur Alyanak , Alexander Romanenko , Anna Grassellino , Shaojiang Zhu

We investigate the pure dephasing of a Josephson qubit due to the spectral diffusion of two-level systems that are close to resonance with the qubit. We identify the parameter regime in which this pure dephasing rate can be of the order of…

Quantum Physics · Physics 2024-05-02 Shlomi Matityahu , Alexander Shnirman , Moshe Schechter

The wide-ranging adoption of quantum technologies requires practical, high-performance advances in our ability to maintain quantum coherence while facing the challenge of state collapse under measurement. Here we use techniques from control…

Quantum Physics · Physics 2017-02-01 Sandeep Mavadia , Virginia Frey , Jarrah Sastrawan , Stephen Dona , Michael J. Biercuk