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The interaction between solid-state qubits and their environmental degrees of freedom produces non-unitary effects like decoherence and dissipation. Uncontrolled decoherence is one of the main obstacles that must be overcome in quantum…

Quantum Physics · Physics 2014-11-24 Paula I. Villar , Fernando C. Lombardo

We examine a system in which an impurity qubit is immersed in a quasi-two-dimensional dipolar Bose-Einstein condensate whose collective excitations act as a depasing reservoir for the qubit. The relative dipole-dipole interaction strength…

Quantum Physics · Physics 2024-12-02 Ji-Bing Yuan , Hai-Fei Liu , Ya-Ju Song , Shi-Qing Tang , Xin-Wen Wang , Le-Man Kuang

Small, controllable quantum systems, known as quantum probes, have been proposed to estimate various parameters characterizing complex systems such as the environments of quantum systems. These probes, prepared in some initial state, are…

Quantum Physics · Physics 2021-07-21 Hamza Ather , Adam Zaman Chaudhry

Quantum metrology utilizes quantum effects to reach higher precision measurements of physical quantities compared with their classical counterparts. However the ubiquitous decoherence obstructs its application. Recently, non-Markovian…

Quantum Physics · Physics 2020-03-04 Kai Bai , Hong-Gang Luo , Wenxian Zhang , Meng Xiao

Decoherence in a quantum measurement is typically explained as an interaction with the environment that destroys coherence between the system's eigenstates, a phenomenon known as environment-induced superselection (einselection). In this…

Quantum Physics · Physics 2024-07-19 Xiao Zhang

Different approaches in quantifying environmentally-induced decoherence are considered. We identify a measure of decoherence, derived from the density matrix of the system of interest, that quantifies the environmentally induced error,…

Mesoscale and Nanoscale Physics · Physics 2010-10-12 Arkady Fedorov , Leonid Fedichkin , Vladimir Privman

In this work, we study the quantum Fisher information (QFI) per particle of an open (particles can enter and leave the system) and dissipative (far from thermodynamical equilibrium) steady state system of two qubits in noisy channels. We…

Quantum Physics · Physics 2016-10-07 Azmi Ali Altintas

In recent years, significant progress has been made in utilizing the divergence of spectrum response rate at the exceptional point (EP) for sensing in classical systems, while the use and characterization of quantum EPs for sensing have…

Quantum Physics · Physics 2024-04-08 Chun-Hui Liu , Fu Li , Shengwang Du , Jianming Wen , Lan Yang , Chuanwei Zhang

We utilize quantum Fisher information to investigate the damping parameter precision of a dissipative qubit. PT symmetric non-Hermitian Hamiltonian is used to enhance the parameter precision in two models: one is direct PT symmetric quantum…

Quantum Physics · Physics 2019-08-13 Dong Xie , Chunling Xu

In this paper, we have investigated the preservation of quantum Fisher information of a single-qubit system coupled to a common zero temperature reservoir through the addition of noninteracting qubits. The results show that, the QFI is…

Quantum Physics · Physics 2018-01-17 Youneng Guo , Qinglong Tian , Yunfei Mo , K Zeng

In an open quantum system, we study the evolution of a two-level atom as a detector which interacts with given environments. For a uniformly accelerated two-level atom coupled to a massless scalar field in the Minkowski vacuum, when it…

Quantum Physics · Physics 2020-07-28 Zixu Zhao , Qiyuan Pan , Jiliang Jing

The localization transition can be exploited as a resource for achieving quantum-enhanced sensitivity in parameter estimation. We demonstrate that by employing different classes of localization inducing potentials, one can significantly…

Quantum Physics · Physics 2026-02-03 Ayan Sahoo , Debraj Rakshit

Quantum Fisher information is a central quantity in quantum metrology. We discuss an alternative representation of quantum Fisher information for unitary parametrization processes. The highlight of this representation is that all…

Quantum Physics · Physics 2015-02-25 Jing Liu , Xiaoxing Jing , Xiaoguang Wang

In [Phys. Rev. A 82, 042103 (2010)], the authors showed that "for a class of the non-Markovian master equations in time-local forms", the quantum Fisher information (QFI) flow can be decomposed into additive subflows corresponding to…

Quantum Physics · Physics 2020-12-22 Mihaela Vatasescu

Fragile quantum features such as entanglement are employed to improve the precision of parameter estimation and as a consequence the quantum gain becomes vulnerable to noise. As an established tool to subdue noise, quantum error correction…

Quantum Physics · Physics 2015-06-09 Xiao-Ming Lu , Sixia Yu , C. H. Oh

Due to omnipresent environmental interferences, quantum coherences inevitably undergo irreversible transformations over certain time-scales, thus leading to the loss of encoded information. This process, known as decoherence, has been a…

Quantum Physics · Physics 2014-06-19 Swathi S. Hegde , T. S. Mahesh

We propose to use the quantum Fisher information in characterizing the information flow of open quantum systems. This information-theoretic approach provides a quantitative measure to statistically distinguish Markovian and non-Markovian…

Quantum Physics · Physics 2010-10-12 Xiao-Ming Lu , Xiaoguang Wang , C. P. Sun

We introduce a positive Hermitian operator, the Fisher operator, and use it to examine a measurement process incorporating unitary dynamics and complete measurements. We develop the idea of information complement, the minimization of which…

Quantum Physics · Physics 2009-02-20 Gabriel A. Durkin

We analyze the notion of quantum coherence in an interference experiment. We let the phase shifts fluctuate according to a given statistical distribution and introduce a decoherence parameter, defined in terms of a generalized visibility of…

Quantum Physics · Physics 2010-01-31 A. Mariano , P. Facchi , S. Pascazio

We study how unique features of non-Hermitian lattice systems can be harnessed to improve Hamiltonian parameter estimation in a fully quantum setting. While the so-called non-Hermitian skin effect does not provide any distinct advantage,…

Quantum Physics · Physics 2020-10-26 Alexander McDonald , Aashish A. Clerk