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Fidelity estimation for entangled states constitutes an essential building block for quality control and error detection in quantum networks. Nonetheless, quantum networks often encounter heterogeneous and correlated noise, leading to…

Quantum Physics · Physics 2024-11-18 Liangzhong Ruan , Bas Dirkse

We investigate quantum teleportation through noisy quantum channels by solving analytically and numerically a master equation in the Lindblad form. We calculate the fidelity as a function of decoherence rates and angles of a state to be…

Quantum Physics · Physics 2009-11-07 Sangchul Oh , Soonchil Lee , Hai-woong Lee

In this work, we address the problem of maximizing fidelity in a quantum state transformation process controlled in such a way as to keep decoherence within given bounds. We consider a three-level $\Lambda$-type atom subjected to Markovian…

Quantum Physics · Physics 2022-03-30 Nahid Binandeh Dehaghani , Fernando Lobo Pereira

Quantum dots are nanometer-scale semiconductor particles that exhibit size-dependent quantum mechanical properties. In this work, we investigate the dynamics of quantum correlations, quantified by the concurrence and the quantum coherence,…

Absolutely separable states $\varrho$ remain separable under arbitrary unitary transformations $U \varrho U^{\dag}$. By example of a three qubit system we show that in multipartite scenario neither full separability implies bipartite…

Quantum Physics · Physics 2017-08-21 Sergey N. Filippov , Kamil Yu. Magadov , Maria Anastasia Jivulescu

Fidelity is a figure of merit widely employed in quantum technology in order to quantify similarity between quantum states and, in turn, to assess quantum resources or reconstruction techniques. Fidelities higher than, say, 0.9 or 0.99, are…

Quantum Physics · Physics 2015-06-17 Matteo Bina , Antonio Mandarino , Stefano Olivares , Matteo G. A. Paris

We analyze the decoherence induced on a single qubit by the interaction with a two-level boson system with critical internal dynamics. We explore how the decoherence process is affected by the presence of quantum phase transitions in the…

Quantum Physics · Physics 2015-05-14 A. Relano , J. M. Arias , J. Dukelsky , J. E. Garcia-Ramos , P. Perez-Fernandez

Preserving multipartite entanglement amidst decoherence poses a pivotal challenge in quantum information processing. However, assessing multipartite entanglement in mixed states amid decoherence presenting a formidable task. Employing…

Quantum Physics · Physics 2026-03-16 Sovik Roy , Md. Manirul Ali , Abhijit Mandal , Chandrashekar Radhakrishnan

Protecting entanglement from decoherence is a critical aspect of quantum information processsing. For many-body quantum systems evolving under decoherence, estimating multipartite entanglement is challenging. This challenge can be met up by…

Quantum Physics · Physics 2024-05-22 Chandrashekar Radhakrishnan , Sovik Roy , Ravikumar Chinnarasu , Md. Manirul Ali

Various fidelity measures can be defined between two quantum processes especially when at least one of them is non-unitary. In this paper we consider two such measures of state averaged process fidelity, put forward an efficient procedure…

Mathematical Physics · Physics 2011-11-11 Joydip Ghosh

The practical success of quantum technology hinges on sustaining quantum coherence, which is vulnerable to environmental interactions causing decoherence. We investigate coherence in tripartite quantum systems under the influence of noisy…

Quantum Physics · Physics 2026-03-16 Sovik Roy , Aahaman Kalaiselvan , Chandrashekar Radhakrishnan , Md Manirul Ali

Fidelity and relative entropy are two significant quantities in quantum information theory. We study the quantum fidelity and relative entropy under unitary orbits. The maximal and minimal quantum fidelity and relative entropy between two…

Quantum Physics · Physics 2014-01-15 Lin Zhang , Shao-Ming Fei

A quantum channel is said to be a mixed-unitary channel if it can be expressed as a convex combination of unitary channels. We prove that, given the Choi representation of a quantum channel, it is NP-hard with respect to polynomial-time…

Quantum Physics · Physics 2020-04-22 Colin Do-Yan Lee , John Watrous

Quantum coherence and quantum entanglement are two different manifestations of the superposition principle. In this article we show that the right choice of basis to be used to estimate coherence is the separable basis. The quantum…

The distinction between pure states and mixed states is a kernel ingredient of what is considered to be the standard formulation of quantum mechanics and plays today a kernel role in foundational debates about the meaning of quantum…

History and Philosophy of Physics · Physics 2024-11-01 Christian de Ronde , César Massri

Environmental decoherence occurs when a quantum system interacts with its surroundings, progressively reducing quantum interference and coherence, complicating the preservation of critical quantum properties over time, especially during…

Quantum Physics · Physics 2025-12-18 Naeem Akhtar , Jia-Xin Peng , Tan Hailin , Xiaosen Yang , Dong Wang

We consider a scenario where a party, say, Alice prepares a pure two-qubit (either maximally entangled or non-maximally entangled) state and sends one half of this state to another distant party, say, Bob through a qubit (either unital or…

Quantum Physics · Physics 2021-05-19 Arkaprabha Ghosal , Debarshi Das , Subhashish Banerjee

Quantum coherence, present whenever a quantum system exists in a superposition of multiple classically distinct states, marks one of the fundamental departures from classical physics. Quantum coherence has recently been investigated…

In the field of quantum information theory, the concept of quantum fidelity is employed to quantify the similarity between two quantum states. It has been observed that the fidelity between two states describing a bipartite quantum system…

Quantum Physics · Physics 2023-08-01 Seong-Kun Kim , Yonghae Lee

When a quantum system couples to a scale-invariant environment, what form must its decoherence take? We prove that the answer is unique: under locality, Lorentz invariance, unitarity, and continuous scale invariance, the effect of any such…

High Energy Physics - Phenomenology · Physics 2026-04-20 Carlos Argüelles , Gabriela Barenboim , Gonzalo Herrera , Tanvi Krishnan , Héctor Sanchis
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