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We address the estimation of the coupling constant of the Jaynes-Cummings Hamiltonian for a coupled qubit-oscillator system. We evaluate the quantum Fisher Information (QFI) for the system undergone the Jaynes-Cummings evolution,…

Quantum Physics · Physics 2015-06-03 Marco G. Genoni , Carmen Invernizzi

Recently, Zhong et al. [Phys. Rev. A 87, 022337(2013)] investigated the dynamics of quantum Fisher information (QFI) in the presence of decoherence. We here reform their results and propose two schemes to enhance and preserve the QFIs for a…

Quantum Physics · Physics 2016-10-28 Youneng Guo , Maofa Fang , Gouyou Wang , Jiang Huang , Ke Zeng

Non-Markovian dynamics is central to quantum information processing, as memory effects strongly influence coherence preservation, metrology, and communication. In this work, we investigate the role of stochastic system--bath couplings in…

Quantum Physics · Physics 2025-09-17 Mehboob Rashid , Rayees A Mala , Saima Bashir , Muzaffar Qadir Lone

We investigate the sensitivity with which the temperature and the chemical potential characterizing quantum gases can be measured. We calculate the corresponding quantum Fisher information matrices for both fermionic and bosonic gases. For…

Quantum Physics · Physics 2016-02-01 Ugo Marzolino , Daniel Braun

We theoretically investigate the pure dephasing dynamics of two static impurity qubits embedded within a common environment of ultracold fermionic atoms, which are confined to one spatial dimension. Our goal is to understand how…

Quantum Gases · Physics 2024-02-13 Sindre Brattegard , Mark T. Mitchison

We present a quantum thermometric protocol for the estimation of multiple temperatures within the collisional model framework. Employing the formalism of multiparameter quantum metrology, we develop a systematic strategy to estimate the…

Quantum Physics · Physics 2025-11-26 Srijon Ghosh , Sagnik Chakraborty , Rosario Lo Franco

A scheme is proposed to estimate the system and environmental parameter, the detuning, temperature and the squeezing strength with a high precision by the two-level atom system. It hasn't been reported that the squeezing strength estimation…

Quantum Physics · Physics 2021-05-07 Mengmeng Luo , Wenxiao Liu , Yuetao Chen , Shaoyan Gao

We show that the performance of critical quantum metrology protocols, counter-intuitively, can be enhanced by finite temperature. We consider a toy-model squeezing Hamiltonian, the Lipkin-Meshkov-Glick model and the paradigmatic Ising…

Quantum Physics · Physics 2024-02-23 Laurin Ostermann , Karol Gietka

We study the non-Markovian dynamics of a qubit made up of a two-level atom interacting with an electromagnetic field (EMF) initially at finite temperature. Unlike most earlier studies where the bath is assumed to be fixed, we study the…

Quantum Physics · Physics 2009-11-10 S. Shresta , C. Anastopoulos , A. Dragulescu , B. L. Hu

The rapidly developing quantum technologies and thermodynamics have put forward a requirement to precisely control and measure the temperature of microscopic matter at the quantum level. Many quantum thermometry schemes have been proposed.…

Quantum Physics · Physics 2022-04-01 Ning Zhang , Chong Chen , Si-Yuan Bai , Wei Wu , Jun-Hong An

Quantum Fisher information (QFI) sets the ultimate precision of optical phase measurements and reveals multiphoton entanglement, but it is not accessible with conventional photodetection. We theoretically predict that a photodetector…

Mesoscale and Nanoscale Physics · Physics 2026-04-01 Evgenii Barts , Takahiro Morimoto , Naoto Nagaosa

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

We develop a method to study quantum impurity models, small interacting quantum systems linearly coupled to an environment, in presence of an additional Markovian quantum bath, with a generic non-linear coupling to the impurity. We aim at…

Quantum Physics · Physics 2025-03-10 Orazio Scarlatella , Marco Schirò

Entangled systems with large quantum Fisher information (QFI) can be used to outperform the standard quantum limit of the separable systems in quantum metrology. However, the interaction between the system and the environments inevitably…

Quantum Physics · Physics 2016-08-23 Guofeng Zhang , Hanjie Zhu

Coherence time is an important resource to generate enhancement in quantum metrology. In this work, based on continuous-variable models, we propose a new design of the signal-probe Hamiltonian which generates an exponential enhancement of…

Quantum Physics · Physics 2021-07-01 Li Sun , Xi He , Chenglong You , Chufan Lv , Bo Li , Seth Lloyd , Xiaoting Wang

Gaussian quantum channels constitute a cornerstone of continuous-variable quantum information science, underpinning a wide array of protocols in quantum optics and quantum metrology. While the action of such channels on arbitrary states is…

Quantum Physics · Physics 2026-02-24 Pritam Chattopadhyay , Saikat Sur , Jonas F. G. Santos

We provide new operational significance of nonclassicality in nonequilibrium temperature estimation of bosonic baths with Gaussian probe states and Gaussian dynamics. We find a bound on the thermometry performance using classical probe…

We consider a general model of unitary parameter estimation in presence of Markovian noise, where the parameter to be estimated is associated with the Hamiltonian part of the dynamics. In absence of noise, unitary parameter can be estimated…

Quantum Physics · Physics 2018-08-17 R. Demkowicz-Dobrzanski , J. Czajkowski , P. Sekatski

We consider a discrete-time non-Hamiltonian dynamics of a quantum system consisting of a finite sample locally coupled to several bi-infinite reservoirs of fermions with a translation symmetry. In this setup, we compute the asymptotic…

Mathematical Physics · Physics 2022-09-21 Simon Andréys , Alain Joye , Renaud Raquépas

We consider the estimation of an unknown parameter $\theta$ through a quantum probe at thermal equilibrium. The probe is assumed to be in a Gibbs state according to its Hamiltonian $H_\theta$, which is divided in a parameter-encoding term…

Quantum Physics · Physics 2026-01-23 Paolo Abiuso , Pavel Sekatski , John Calsamiglia , Martí Perarnau-Llobet
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