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Spin squeezing generated via inter-atom entanglement in multilevel atomic ensembles provides a powerful resource for quantum-enhanced metrology. Existing schemes that harness internal atomic degrees of freedom to boost squeezing typically…

Quantum Physics · Physics 2026-05-18 Zhiwei Hu , Youwei Zhang , Junlei Duan , Mingfeng Wang , Yanhong Xiao

We study manipulation of entanglement between two identical networks of quantum mechanical particles. Firstly, we reduce the problem of entanglement transfer to the problem of quantum state transfer. Then, we consider entanglement…

Quantum Physics · Physics 2011-01-27 Andrea Casaccino , Stefano Mancini , Simone Severini

Entanglement is an important resource that allows quantum technologies to go beyond the classically possible. There are many ways quantum systems can be entangled, ranging from the archetypal two-qubit case to more exotic scenarios of…

Quantum Physics · Physics 2019-06-27 Nicolai Friis , Giuseppe Vitagliano , Mehul Malik , Marcus Huber

Entanglement witnesses provide tools to detect entanglement in experimental situations without the need of having full tomographic knowledge about the state. If one estimates in an experiment an expectation value smaller than zero, one can…

Quantum Physics · Physics 2013-08-28 Jens Eisert , Fernando G. S. L. Brandao , Koenraad M. R. Audenaert

We use Nuclear Magnetic Resonance (NMR) to experimentally generate a bound entangled (more precisely: pseudo bound entangled) state, i.e. a quantum state which is non-distillable but nevertheless entangled. Our quantum system consists of…

Quantum Physics · Physics 2010-11-08 H. Kampermann , X. Peng , D. Bruss , D. Suter

We consider graph states generated by operator of evolution with Ising Hamiltonian. The geometric measure of entanglement of a spin with other spins in the graph state is obtained analytically and quantified on IBM's quantum computer, IBM Q…

Quantum Physics · Physics 2021-04-27 Kh. P. Gnatenko , V. M. Tkachuk

We provide a summary of both seminal and recent results on typical entanglement. By typical values of entanglement, we refer here to values of entanglement quantifiers that (given a reasonable measure on the manifold of states) appear with…

Quantum Physics · Physics 2014-09-05 Oscar C. O. Dahlsten , Cosmo Lupo , Stefano Mancini , Alessio Serafini

We investigate the evolution of entanglement in multiple-quantum (MQ) NMR experiments in crystals with pairs of close nuclear spins-1/2. The initial thermodynamic equilibrium state of the system in a strong external magnetic field evolves…

Quantum Physics · Physics 2009-11-13 E. B. Fel'dman , A. N. Pyrkov

Quantum entanglement has been identified as a crucial concept underlying many intriguing phenomena in condensed matter systems, such as topological phases or many-body localization. Recently, instead of considering mere quantifiers of…

Quantum Physics · Physics 2024-02-12 Niklas Euler , Martin Gärttner

Entanglement witnesses based on first and second moments exist in the form of spin-squeezing criteria for the detection of particle entanglement from collective measurements, and in form of modified uncertainty relations for the detection…

Quantum Physics · Physics 2022-01-21 Matteo Fadel , Manuel Gessner

Entanglement measures such as the entanglement entropy have become an indispensable tool to identify the fundamental character of ground states of interacting quantum many-body systems. For systems of interacting spin or bosonic degrees of…

Strongly Correlated Electrons · Physics 2014-08-27 Peter Broecker , Simon Trebst

We derive conditions in the form of inequalities to detect the genuine $N$-partite entanglement of $N$ systems. The inequalities are expressed in terms of variances of spin operators, and can be tested by local spin measurements performed…

Quantum Physics · Physics 2020-09-24 R. Y. Teh , M. D. Reid

Detecting individual spins--including stable and metastable states--represents a fundamental challenge in quantum sensing with broad applications across condensed matter physics, quantum chemistry, and single-molecule magnetic resonance…

Measuring entanglement entropy in interacting, multipartite systems remains a significant experimental challenge. We address this challenge by developing a protocol to measure von Neumann entropy (VNE) and mutual information in quantum…

Mesoscale and Nanoscale Physics · Physics 2025-08-05 Zhenhua Zhu , Gu Zhang , Dong E. Liu

In this article, we present a novel approach to investigating entanglement in the context of quantum computing. Our methodology involves analyzing reduced density matrices at different stages of a quantum algorithm's execution and…

Quantum Physics · Physics 2024-03-14 Ruge Lin

Studying entanglement growth in quantum dynamics provides both insight into the underlying microscopic processes and information about the complexity of the quantum states, which is related to the efficiency of simulations on classical…

Quantum Gases · Physics 2013-09-23 J. Schachenmayer , B. P. Lanyon , C. F. Roos , A. J. Daley

We present a method for improving measurements of the entanglement R\'enyi entropies in quantum Monte Carlo simulations by relating them with measurements of participation R\'enyi entropies. Exploiting the capability of building improved…

Strongly Correlated Electrons · Physics 2014-11-11 David J. Luitz , Xavier Plat , Nicolas Laflorencie , Fabien Alet

Entanglement can improve the measurement precision of quantum sensors beyond the shot noise limit. Neutral atoms, the basis of some of the most precise and accurate optical clocks and interferometers, do not naturally exhibit all-to-all…

Scrambling unitary dynamics in a quantum system transmutes local quantum information into a non-local web of correlations which manifests itself in a complex spatio-temporal pattern of entanglement. In such a context, we show there can…

Quantum Physics · Physics 2025-06-02 Alan Sherry , Sthitadhi Roy

Entanglement plays a crucial role in quantum information science and many-body physics, yet quantifying it in mixed quantum many-body systems has remained a notoriously difficult problem. Here, we introduce families of quantitative…

Quantum Physics · Physics 2025-07-21 Poetri Sonya Tarabunga , Tobias Haug