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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

Noise is the central obstacle to building large-scale quantum computers. Quantum systems with sufficiently uncorrelated and weak noise could be used to solve computational problems that are intractable with current digital computers. There…

Quantum Physics · Physics 2021-04-19 Robin Harper , Steven T. Flammia , Joel J. Wallman

A closed quantum system is defined as completely controllable if an arbitrary unitary transformation can be executed using the available controls. In practice, control fields are a source of unavoidable noise. Can one design control fields…

Quantum Physics · Physics 2015-05-27 Michael Khasin , Ronnie Kosloff

The efficiency of the future devices for quantum information processing is limited mostly by the finite decoherence rates of the qubits. Recently a substantial progress was achieved in enhancing the time, which a solid-state qubit…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 J Bergli , Y M Galperin , B L Altshuler

This paper presents several results on performance analysis for a class of uncertain linear quantum systems subject to either quadratic or non-quadratic perturbations in the system Hamiltonian. Also, coherent guaranteed cost controllers are…

Quantum Physics · Physics 2014-04-16 Chengdi Xiang , Ian R. Petersen , Daoyi Dong

Quantum error mitigation (QEM) is a class of promising techniques capable of reducing the computational error of variational quantum algorithms tailored for current noisy intermediate-scale quantum computers. The recently proposed…

Quantum Physics · Physics 2022-05-17 Yifeng Xiong , Soon Xin Ng , Lajos Hanzo

It is widely accepted that noisy quantum devices are limited to logarithmic depth circuits unless mid-circuit measurements and error correction are employed. However, this conclusion holds only for unital error channels, such as…

Quantum Physics · Physics 2024-11-08 Oles Shtanko , Kunal Sharma

Noise and errors are inevitable parts of any practical implementation of a quantum computer. As a result, large-scale quantum computation will require ways to detect and correct errors on quantum information. Here, we present such a quantum…

A formulation for evaluating the performance of quantum error correcting codes for a general error model is presented. In this formulation, the correlation between errors is quantified by a Hamiltonian description of the noise process. We…

Quantum Physics · Physics 2009-11-13 A. Shabani

Quantum metrology based on quantum entanglement and quantum coherence improves the accuracy of measurement. In this paper, we briefly review the schemes of quantum metrology in various complex systems, including non-Markovian noise,…

Quantum Physics · Physics 2024-01-18 Qing Ai , Yang-Yang Wang , Jing Qiu

Finding ground states and low-lying excitations of a given Hamiltonian is one of the most important problems in many fields of physics. As a novel approach, quantum computing on Noisy Intermediate-Scale Quantum (NISQ) devices offers the…

Quantum error mitigation (QEM) has been proposed as an alternative method of quantum error correction to compensate errors in quantum systems without qubit overhead. While Markovian gate errors on digital quantum computers have been mainly…

Quantum Physics · Physics 2021-02-09 Hideaki Hakoshima , Yuichiro Matsuzaki , Suguru Endo

Access to quantum computing is steadily increasing each year as the speed advantage of quantum computers solidifies with the growing number of usable qubits. However, the inherent noise encountered when running these systems can lead to…

Quantum Physics · Physics 2024-09-24 Jon Gardeazabal-Gutierrez , Erik B. Terres-Escudero , Pablo García Bringas

We have proved new estimates for the coherent control errors of quantum circuits used in quantum computing. These estimates essentially take into account the commutator properties of the Hamiltonians and are based on the formulas of the…

Quantum Physics · Physics 2023-10-12 Vladyslav Bivziuk , Vitalii Slynko

Current quantum noise can be pictured as a sum over transitions through which the electronic system exchanges energy with its environment. We formulate this picture and use it to show which type of current correlators are measurable, and in…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 U. Gavish , Y. Imry , Y. Levinson

Decoherence-free subsystems have been successfully developed as a tool to preserve fragile quantum information against noises. In this letter, we develop a structure theory for decoherence-free subsystems. Based on it, we present an…

Quantum Physics · Physics 2018-02-15 Ji Guan , Yuan Feng , Mingsheng Ying

Most previous efforts of quantum error correction focused on either extending classical error correction schemes to the quantum regime by performing a perfect correction on a subset of errors, or seeking a recovery operation to maximize the…

Quantum Physics · Physics 2023-09-06 Chengjie Zhang , Liangsheng Li , Guodong Lu , Haidong Yuan , Runyao Duan

Noise in contemporary quantum hardware is highly non-uniform across qubits and couplers, giving rise to localized low-noise "islands" within otherwise noisy device topologies. As quantum workloads scale, executions are increasingly forced…

Quantum metrology has many important applications in science and technology, ranging from frequency spectroscopy to gravitational wave detection. Quantum mechanics imposes a fundamental limit on measurement precision, called the Heisenberg…

Quantum Physics · Physics 2018-02-05 Sisi Zhou , Mengzhen Zhang , John Preskill , Liang Jiang

Quantum error correction is expected to be essential in large-scale quantum technologies. However, the substantial overhead of qubits it requires is thought to greatly limit its utility in smaller, near-term devices. Here we introduce a new…

Quantum Physics · Physics 2020-01-20 David Layden , Mo Chen , Paola Cappellaro