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Related papers: Noisy frequency estimation with noisy probes

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We consider entanglement distillation with noisy operations in which quantum measurements that constitute a general quantum operation are particularly noisy. We present a protocol for purifying noisy measurements and show that imperfect…

Quantum Physics · Physics 2025-02-11 Jaemin Kim , Jiyoung Yun , Joonwoo Bae

We present a general framework to study the simultaneous estimation of multiple phases in the presence of noise as a discretized model for phase imaging. This approach can lead to nontrivial bounds of the precision for multiphase…

Quantum Physics · Physics 2014-08-12 Jie-Dong Yue , Yu-Ran Zhang , Heng Fan

We extend the validity of Hardy's nonlocality without inequalities proof to cover the case of special one-parameter classes of non-pure statistical operators. These mixed states are obtained by mixing the Hardy states with a completely…

Quantum Physics · Physics 2009-11-13 GianCarlo Ghirardi , Luca Marinatto

We formally study the effects of a restricted single-qubit noise model inspired by real quantum hardware, and corruption in quantum training data, on the performance of binary classification using quantum circuits. We find that, under the…

Quantum Physics · Physics 2023-05-09 Yonghoon Lee , Doga Murat Kurkcuoglu , Gabriel Nathan Perdue

Quantum computers in the NISQ era are prone to noise. A range of quantum error mitigation techniques has been proposed to address this issue. Zero-noise extrapolation (ZNE) stands out as a promising one. ZNE involves increasing the noise…

Quantum Physics · Physics 2024-02-01 Hrushikesh Patil , Peiyi Li , Ji Liu , Huiyang Zhou

We consider entanglement-assisted frequency estimation by Ramsey interferometry, in the presence of dephasing noise from spatiotemporally correlated environments.By working in the widely employed local estimation regime, we show that even…

Quantum Physics · Physics 2023-09-20 Francisco Riberi , Gerardo Paz-Silva , Lorenza Viola

We consider realistic measurement systems, where measurements are accompanied by decoherence processes. The aim of this work is the construction of methods and algorithms for precise quantum measurements with fidelity close to the…

Quantum Physics · Physics 2017-01-10 Yu. I. Bogdanov , B. I. Bantysh , N. A. Bogdanova , A. B. Kvasnyy , V. F. Lukichev

As quantum computing hardware steadily increases in qubit count and quality, one important question is how to allocate these resources to mitigate the effects of hardware noise. In a transitional era between noisy small-scale and fully…

Estimating noise processes is an essential step for practical quantum information processing. Standard estimation tools require consuming valuable quantum resources. Here we ask the question of whether the noise affecting entangled states…

Quantum metrology protocols allow to surpass precision limits typical to classical statistics. However, in recent years, no-go theorems have been formulated, which state that typical forms of uncorrelated noise can constrain the quantum…

Quantum Physics · Physics 2016-03-30 Andrea Smirne , Jan Kolodynski , Susana F. Huelga , Rafal Demkowicz-Dobrzanski

With an ever-expanding ecosystem of noisy and intermediate-scale quantum devices, exploring their possible applications is a rapidly growing field of quantum information science. In this work, we demonstrate that variational quantum…

Quantum Physics · Physics 2021-07-16 Johannes Jakob Meyer , Johannes Borregaard , Jens Eisert

The minimum achievable statistical uncertainty in the estimation of physical parameters is determined by the quantum Fisher information. Its computation for noisy systems is still a challenging problem. Using a variational approach, we…

Quantum Physics · Physics 2012-11-21 B. M. Escher , L. Davidovich , N. Zagury , R. L. de Matos Filho

Quantum instruments describe both the classical outcome and the updated state associated with a quantum measurement. We ask whether these processes can be simulated using only a natural subset of resources, namely projective measurements on…

Quantum Physics · Physics 2025-07-24 Shishir Khandelwal , Armin Tavakoli

Accurate characterization of the noise influencing a quantum system of interest has far-reaching implications across quantum science, ranging from microscopic modeling of decoherence dynamics to noise-optimized quantum control. While the…

Two level systems that can be reliably controlled and measured hold promise in both metrology and as qubits for quantum information science (QIS). When prepared in a superposition of two states and allowed to evolve freely, the state of the…

Mesoscale and Nanoscale Physics · Physics 2013-04-09 O. E. Dial , M. D. Shulman , S. P. Harvey , H. Bluhm , V. Umansky , A. Yacoby

The measurement of a quantum two-level system, or a qubit in modern terminology, often involves an electromagnetic field that interacts with the qubit, before the field is measured continuously and the qubit state is inferred from the noisy…

Quantum Physics · Physics 2014-08-27 Shilin Ng , Mankei Tsang

Spatially correlated noise poses a significant challenge to fault-tolerant quantum computation by breaking the assumption of independent errors. Existing methods such as cycle benchmarking and quantum process tomography can characterize…

Quantum Physics · Physics 2026-02-11 Balázs Gulácsi , Joris Kattemölle , Guido Burkard

When error correction becomes possible it will be necessary to dedicate a large number of physical qubits to each logical qubit. Error correction allows for deeper circuits to be run, but each additional physical qubit can potentially…

Sampling from the output distribution of chaotic quantum evolutions, and of pseudo-random universal quantum circuits in particular, has been proposed as a prominent milestone for near-term quantum supremacy. The same paper notes that…

Quantum Physics · Physics 2017-08-08 Sergio Boixo , Vadim N. Smelyanskiy , Hartmut Neven

Quantum noise is conventionally viewed as a fundamental obstacle in near-term quantum computing, motivating extensive error correction and mitigation strategies. We present numerical evidence that challenges this consensus. Through…

Quantum Physics · Physics 2026-01-21 Linghua Zhu , Yulong Dong , Ziyu Zhang , Xiaosong Li