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Related papers: Beating noise with abstention in state estimation

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We consider the problem of parameter estimation in a partially observed linear Gaussian system with small noises in the state and observation equations. We describe asymptotic properties of the MLE and Bayes estimators in the setting with…

Statistics Theory · Mathematics 2020-10-16 Yury A. Kutoyants

Phase insensitive optical amplification of an unknown quantum state is known to be a fundamentally noisy operation that inevitably adds noise to the amplified state [1 - 5]. However, this fundamental noise penalty in amplification can be…

Entanglement plays an indispensable role in numerous quantum information and quantum computation tasks, underscoring the need for efficiently verifying entangled states. In recent years, quantum state verification has received increasing…

Quantum Physics · Physics 2025-12-15 Lan Zhang , Yinfei Li , Ye-Chao Liu , Jiangwei Shang

We show that non-exponential fidelity decays in randomized benchmarking experiments on quantum dot qubits are consistent with numerical simulations that incorporate low-frequency noise. By expanding standard randomized benchmarking analysis…

Quantum Physics · Physics 2015-08-17 M. A. Fogarty , M. Veldhorst , R. Harper , C. H. Yang , S. D. Bartlett , S. T. Flammia , A. S. Dzurak

Quantum-enhanced measurements exploit quantum mechanical effects to provide ultra-precise estimates of physical variables for use in advanced technologies, such as frequency calibration of atomic clocks, gravitational waves detection, and…

Quantum Physics · Physics 2014-07-28 J. Calsamiglia , B. Gendra , R. Munoz-Tapia , E. Bagan

We introduce an approximate description of an $N$-qubit state, which contains sufficient information to estimate the expectation value of any observable to a precision that is upper bounded by the ratio of a suitably-defined seminorm of the…

Quantum Physics · Physics 2021-03-17 Marco Paini , Amir Kalev , Dan Padilha , Brendan Ruck

We propose a quantum-state-certification protocol for stabilizer states, motivated by application in in-situ testing of NISQ-era quantum computer systems: The number of qubits is bounded, and in terms of cost of running the protocol,…

Quantum Physics · Physics 2025-07-21 Dirk Oliver Theis

Noise is a major challenge in quantum computing, affecting the reliability of quantum protocols. In this work, we analytically study the impact of various noise processes, such as depolarization, bit flip, and phase flip, on the quantum…

Quantum Physics · Physics 2026-04-10 Imama Tul Birrah Khan , Muhammad Faryad

We discuss the possibility of protecting the state of a quantum system that goes through noise by measurements and operations before and after the noise process. We extend our previous result on nonexistence of "truly quantum" protocols…

Quantum Physics · Physics 2017-09-26 Hiroaki Wakamura , Ryûitirô Kawakubo , Tatsuhiko Koike

We identify a noise model that ensures the functioning of an echo state network employing a gate-based quantum computer for reservoir computing applications. Energy dissipation induced by amplitude damping drastically improves the…

Quantum Physics · Physics 2025-06-24 Francesco Monzani , Emanuele Ricci , Luca Nigro , Enrico Prati

Despite remarkable progress made in natural language processing, even the state-of-the-art models often make incorrect predictions. Such predictions hamper the reliability of systems and limit their widespread adoption in real-world…

Computation and Language · Computer Science 2023-05-04 Neeraj Varshney , Chitta Baral

Phase estimation in quantum interferometry is a major scenario where the quantum advantage is significantly revealed. Recently, the optimal finite-dimensional probe states (OFPSs) for phase estimation in two-mode quantum interferometry have…

Quantum Physics · Physics 2026-05-07 Jin-Feng Qin , Jing Liu

Noise is often regarded as a limitation of quantum computers. In this work, we show that in the dynamical mean field theory (DMFT) approach to strongly-correlated systems, it can actually be harnessed to our advantage. Indeed, DMFT maps a…

Quantum Physics · Physics 2025-08-01 Corentin Bertrand , Pauline Besserve , Michel Ferrero , Thomas Ayral

Quantum error mitigation is essential for computing on the noisy quantum computer with a limited number of qubits. In this paper, we propose a practical protocol of error mitigation by virtually purifying the quantum state without qubit…

Quantum Physics · Physics 2022-03-02 Mingxia Huo , Ying Li

Noise mechanisms in quantum systems can be broadly characterized as either coherent (i.e., unitary) or incoherent. For a given fixed average error rate, coherent noise mechanisms will generally lead to a larger worst-case error than…

Quantum Physics · Physics 2019-01-29 Joel J. Wallman , Christopher Granade , Robin Harper , Steven T. Flammia

Quantum state purification is crucial in quantum communication and computation, aiming to recover a purified state from multiple copies of an unknown noisy state. This work introduces a general state purification framework designed to…

Quantum Physics · Physics 2024-09-27 Hongshun Yao , Yu-Ao Chen , Erdong Huang , Kaichu Chen , Honghao Fu , Xin Wang

Quantum technologies rely heavily on accurate control and reliable readout of quantum systems. Current experiments are limited by numerous sources of noise that can only be partially captured by simple analytical models and additional…

We propose a single auxiliary-assisted purification-based framework for quantum error correction, capable of correcting errors that drive a system from its ground-state subspace into excited-state sectors. The protocol consists of a joint…

Quantum Physics · Physics 2025-12-11 Chandrima B. Pushpan , Tanoy Kanti Konar , Aditi Sen De , Amit Kumar Pal

Non-unitary state preparation protocols such as imaginary time evolution (ITE) offer substantial advantages relative to unitary ones, including the ability to prepare certain long-range correlated states more efficiently. Here, we ask…

Quantum Physics · Physics 2025-03-20 Aleksei Khindanov , Yongxin Yao , Thomas Iadecola

Analog quantum simulation is a promising path towards solving classically intractable problems in many-body physics on near-term quantum devices. However, the presence of noise limits the size of the system and the length of time that can…

Quantum Physics · Physics 2024-10-22 Yiyi Cai , Yu Tong , John Preskill