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We address the problem of parameter identification for a single open qubit subjected to relaxation and dephasing. Our approach is based on selecting a minimal set of carefully chosen qubit configurations that can be reliably prepared and…

Optimization and Control · Mathematics 2025-12-09 Ghaieth Aloui , Ivan Beschastnyi , Ludovic Sacchelli

In this work, we study Bayesian quantum parameter estimation given a finite number of uses of the process encoding one or more unknown physical quantities. For multiple uses, it is conventional to classify quantum metrological protocols as…

Quantum Physics · Physics 2026-02-11 Erik L. André , Jessica Bavaresco , Mohammad Mehboudi

We introduce a quantum error mitigation technique based on probabilistic error cancellation to eliminate errors which have accumulated during the application of a quantum circuit. Our approach is based on applying an optimal "denoiser"…

Quantum Physics · Physics 2024-05-21 Maurits S. J. Tepaske , David J. Luitz

We provide a feasible necessary and sufficient condition for when an unknown quantum operation (quantum device) secretely selected from a set of known quantum operations can be identified perfectly within a finite number of queries, and…

Quantum Physics · Physics 2013-05-29 Runyao Duan , Yuan Feng , Mingsheng Ying

The simulation of electronic properties is a pivotal issue in modern electronic structure theory, driving significant efforts over the past decades to develop protocols for computing energy derivatives. In this work, we address this problem…

Quantum phase estimation algorithm (PEA) is one of the most important algorithms in early studies of quantum computation. It is also a key for many other quantum algorithms, such as the quantum counting algorithm and the Shor's integer…

Quantum Physics · Physics 2022-10-04 Xi Lu , Hongwei Lin

Quantum-enhanced parameter estimation has widespread applications in many fields. An important issue is to protect the estimation precision against the noise-induced decoherence. Here we develop a general theoretical framework for improving…

Quantum Physics · Physics 2019-04-03 Yao Ma , Mi Pang , Libo Chen , Wen Yang

Quantum noise constitutes a fundamental obstacle to realizing practical quantum technologies. To address the pivotal challenge of identifying quantum systems least affected by noise, we introduce the purest quantum state identification,…

Quantum Physics · Physics 2025-09-24 Yingqi Yu , Honglin Chen , Jun Wu , Wei Xie , Xiangyang Li

We address estimation of one-parameter qubit gates in the presence of phase diffusion. We evaluate the ultimate quantum limits to precision, seek for optimal probes and measurements, and demonstrate an optimal estimation scheme for…

Quantum Physics · Physics 2013-01-16 D. Brivio , S. Cialdi , S. Vezzoli , B. Teklu , M. G. Genoni , S. Olivares , M. G. A. Paris

Quantum state discrimination is a fundamental concept in quantum information theory, which refers to a class of techniques to identify a specific quantum state through a positive operator-valued measure. In this work, we investigate how…

Quantum Physics · Physics 2025-07-09 Hyunho Cha , Jungwoo Lee

The quantum variables that can be accessed directly by experiments are described by observables. Therefore, physical parameters can only be evaluated indirectly, via estimations based on experimental measurement results. I show that the…

Quantum Physics · Physics 2012-12-12 B. M. Escher

Achieving ultimate bounds in estimation processes is the main objective of quantum metrology. In this context, several problems require measurement of multiple parameters by employing only a limited amount of resources. To this end,…

Higher-dimensional quantum systems (qudits) offer advantages in information encoding, error resilience, and compact gate implementations, and naturally arise in platforms such as superconducting and solid-state systems. However, realistic…

Quantum Physics · Physics 2025-06-17 Yule Mayevsky , Akram Youssry , Ritik Sareen , Gerardo A. Paz-Silva , Alberto Peruzzo

The accurate estimation of observables is a crucial task in quantum computing. Recent advances have highlighted the need for (a) specialized protocols for qudit-based devices, that include (b) error-aware strategies. Here, we present…

Quantum Error Mitigation (QEM) enables the extraction of high-quality results from the presently-available noisy quantum computers. In this approach, the effect of the noise on observables of interest can be mitigated using multiple…

Quantum Physics · Physics 2023-11-23 Ivan Henao , Jader P. Santos , Raam Uzdin

Using the necessary and sufficient conditions, minimum error discrimination among two sets of similarity transformed equiprobable quantum qudit states is investigated. In the case that the unitary operators are generating sets of two…

Quantum Physics · Physics 2016-11-25 M. A. Jafarizadeh , Y. Mazhari Khiavi , Y. Akbari Kourbolagh

A generic qubit unitary operator affected by quantum noise is duplicated and inserted in a coherently superposed channel, superposing two paths offered to a probe qubit across the noisy unitary, and driven by a control qubit. A…

Quantum Physics · Physics 2021-10-14 Francois Chapeau-Blondeau

Quantum machines are among the most promising technologies expected to provide significant improvements in the following years. However, bridging the gap between real-world applications and their implementation on quantum hardware is still…

Current techniques in quantum process tomography typically return a single point estimate of an unknown process based on a finite albeit large amount of measurement data. Due to statistical fluctuations, however, other processes close to…

Quantum Physics · Physics 2019-05-15 Le Phuc Thinh , Philippe Faist , Jonas Helsen , David Elkouss , Stephanie Wehner

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