English
Related papers

Related papers: Maximal Quantum Fisher Information for Mixed State…

200 papers

We explore precision in a measurement process incorporating pure probe states, unitary dynamics and complete measurements via a simple formalism. The concept of `information complement' is introduced. It undermines measurement precision and…

Quantum Physics · Physics 2010-02-17 Gabriel A. Durkin

Quantum systems used for metrology can offer enhanced precision over their classical counterparts. The design of quantum sensors can be optimized by maximizing the quantum Fisher information (QFI), which characterizes the precision of…

Quantum Physics · Physics 2025-08-26 George Mihailescu , Anthony Kiely , Andrew K. Mitchell

Quantum metrology is a rapidly developing branch of quantum technologies. While various theories have been established on quantum metrology for Markovian processes, i.e., quantum channel estimation, quantum metrology for non-Markovian…

Quantum Physics · Physics 2021-08-04 Anian Altherr , Yuxiang Yang

In this article, we study the problem of comparing mixed quantum states: given $n$ unknown mixed quantum states, can one determine whether they are identical or not with an unambiguous quantum measurement? We first study universal…

Quantum Physics · Physics 2015-05-18 Shengshi Pang , Shengjun Wu

We exhibit measurements for optimal state estimation which have a finite number of outcomes. This is achieved by a connection between finite optimal measurements and Gauss quadratures. The example we consider to illustrate this connection…

Quantum Physics · Physics 2010-02-18 Sofyan Iblisdir , Jérémie Roland

Bounds analogous to entropic uncertainty relations allow one to design practical tests to detect quantum entanglement by a collective measurement performed on several copies of the state analyzed. This approach, initially worked out for…

Quantum Physics · Physics 2013-01-04 Łukasz Rudnicki , Zbigniew Puchała , Paweł Horodecki , Karol Życzkowski

Studies of quantum metrology have shown that the use of many-body entangled states can lead to an enhancement in sensitivity when compared to product states. In this paper, we quantify the metrological advantage of entanglement in a setting…

The problem of quantum metrology under the context of a particular non-Markovian quantum evolution is explored. We study the dynamics of the quantum Fisher information (QFI) of a composite quantum probe coupled to a Lorentzian environment,…

Quantum Physics · Physics 2020-09-02 Nicolás Mirkin , Martin Larocca , Diego Wisniacki

The efficiency of a quantum metrology protocol can be significantly diminished by the interaction of the system with its environment, leading to a loss of purity and, as a result, a mixed state for the probing system. An example is the…

Quantum Physics · Physics 2025-02-28 Eduardo Serrano-Ensástiga , Chryssomalis Chryssomalakos , John Martin

Deterministic discrimination of nonorthogonal states is forbidden by quantum measurement theory. However, if we do not want to succeed all the time, i.e. allow for inconclusive outcomes to occur, then unambiguous discrimination becomes…

Quantum Physics · Physics 2009-11-11 Janos Bergou , Ulrike Herzog , Mark Hillery

Photonic states with large and fixed photon numbers, such as Fock states, enable quantum-enhanced metrology but remain an experimentally elusive resource. A potentially simple, deterministic and scalable way to generate these states…

Quantum Physics · Physics 2019-04-17 V. Paulisch , M. Perarnau-Llobet , A. González-Tudela , J. I. Cirac

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

We consider the problem of deciding whether a given state preparation, i.e., a source of quantum states, is accurate, namely produces states close to a target one within a prescribed threshold. We show that, when multiple measurements need…

Quantum Physics · Physics 2024-01-22 Weichao Liang , Francesco Ticozzi , Giuseppe Vallone

We address a broad class of optimization problems of finding quantum measurements, which includes the problems of finding an optimal measurement in the Bayes criterion and a measurement maximizing the average success probability with a…

Quantum Physics · Physics 2015-06-23 Kenji Nakahira , Kentaro Kato , Tsuyoshi Sasaki Usuda

The traditional framework of quantum metrology commonly assumes unlimited access to resources, overlooking resource constraints in realistic scenarios. As such, the optimal strategies therein can be infeasible in practice. Here, we…

Quantum Physics · Physics 2026-02-25 Longyun Chen , Yuxiang Yang

The problem of discriminating with minimum error between two mixed quantum states is reviewed, with emphasize on the detection operators necessary for performing the measurement. An analytical result is derived for the minimum probability…

Quantum Physics · Physics 2009-11-10 Ulrike Herzog

In this paper, we consider the problem of unambiguous discrimination between a set of mixed quantum states. We first divide the density matrix of each mixed state into two parts by the fact that it comes from ensemble of pure quantum…

Quantum Physics · Physics 2007-05-23 Chi Zhang , Yuan Feng , Ming Sheng Ying

We study the geometric measure of quantum coherence recently proposed in [Phys. Rev. Lett. 115, 020403 (2015)]. Both lower and upper bounds of this measure are provided. These bounds are shown to be tight for a class of important coherent…

Quantum Physics · Physics 2017-03-14 Hai-Jun Zhang , Bin Chen , Ming Li , Shao-Ming Fei , Gui-Lu Long

We combine traditional pointer-based simultaneous measurements of conjugate observables with the concept of quantum Brownian motion of multipartite systems to phenomenologically model simultaneous measurements of conjugate observables in a…

Quantum Physics · Physics 2014-05-14 Raoul Heese , Matthias Freyberger

Critical metrology relies on the precise preparation of a system in its ground state near a quantum phase transition point where quantum correlations get very strong. Typically this increases the quantum Fisher information with respect to…

Quantum Physics · Physics 2024-02-12 Christoph Hotter , Helmut Ritsch , Karol Gietka