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Einstein-Podolsky-Rosen (EPR) steering is an intermediate type of quantum nonlocality which sits between entanglement and Bell nonlocality. A set of correlations is Bell nonlocal if it does not admit a local hidden variable (LHV) model,…

Quantum Physics · Physics 2017-06-28 Quan Quan , Huangjun Zhu , Heng Fan , Wen-Li Yang

We report on the generation of a continuous variable Einstein-Podolsky-Rosen (EPR) entanglement using an optical fibre interferometer. The Kerr nonlinearity in the fibre is exploited for the generation of two independent squeezed beams.…

Quantum Physics · Physics 2009-11-07 Ch. Silberhorn , P. K. Lam , O. Weiss , F. Koenig , N. Korolkova , G. Leuchs

We provide an explicit construction of entangled states in a noncommutative space with nonclassical states, particularly with the squeezed states. Noncommutative systems are found to be more entangled than the usual quantum mechanical…

Quantum Physics · Physics 2015-06-18 Sanjib Dey , Véronique Hussin

The Einstein-Podolsky-Rosen (EPR) steering is an intermediate quantum nonlocality between entanglement and Bell nonlocality, which plays an important role in quantum information processing tasks. In the past few years, the investigations…

Quantum Physics · Physics 2020-04-21 Huan Yang , Zhi-Yong Ding , Dong Wang , Hao Yuan , Xue-Ke Song , Jie Yang , Chang-Jin Zhang , Liu Ye

We investigate a new class of entangled states, which we call 'hyperentangled',that have EPR correlations identical to those in the vacuum state of a relativistic quantum field. We show that whenever hyperentangled states exist in any…

Quantum Physics · Physics 2009-10-30 Rob Clifton , David V. Feldman , Michael L. G. Redhead , Alexander Wilce

Quantum entanglement and Einstein-Podolsky-Rosen (EPR) steering are valuable resources in quantum information processing. How to enhance the quantum entanglement and EPR steering of coupled optomechanical systems with a weak squeezed vacuum…

Quantum Physics · Physics 2023-10-24 Shao-Xiong Wu , Cheng-Hua Bai , Gang Li , Chang-shui Yu , Tiancai Zhang

We identify a class of two-mode squeezed states which are parametrized by an angular variable ${0\le\theta<2\pi}$ and a squeezing parameter $r$. We show that, for a large squeezing value, these states are either (almost) maximally entangled…

Quantum Physics · Physics 2015-05-18 Amir Kalev , Faqir C. Khanna , Michael Revzen

We describe an entanglement purification protocol to generate maximally entangled states with high efficiencies from two-mode squeezed states or from mixed Gaussian continuous entangled states. The protocol relies on a local quantum…

Quantum Physics · Physics 2009-10-31 Lu-Ming Duan , G. Giedke , J. I. Cirac , P. Zoller

Coherent states with large amplitudes are traditionally thought of as the best quantum mechanical approximation of classical behavior. Here we argue that, far from being classical, coherent state are in fact highly entangled. We demonstrate…

Quantum Physics · Physics 2007-05-23 D. Kaszlikowski , V. Vedral

We investigate the connection between entanglement and non-locality between continuous-variable bipartite Gaussian states. The investigation initiates with formulating non-locality by using the phase-space Wigner representation of Bell's…

Quantum Physics · Physics 2025-07-31 Souvik Agasti

We use the uncertainty relation between the operators associated to the total number of particles and to the relative phase of two bosonic modes to construct entanglement and Einstein-Podolsky-Rosen steering criteria. These can be tested…

Quantum Physics · Physics 2020-06-12 Matteo Fadel , Laura Ares , Alfredo Luis , Qiongyi He

The entanglement of formation (EOF) is computed for arbitrary two-mode Gaussian states. Apart from a conjecture, our analysis rests on two main ingredients. The first is a four-parameter canonical form we develop for the covariance matrix,…

Quantum Physics · Physics 2008-08-13 J. Solomon Ivan , R. Simon

We explore the possibility of entanglement detection in continuous variable systems by entanglement witnesses based on covariance matrices, constructible from random homodyne measurements. We propose new linear constraints characterizing…

Quantum Physics · Physics 2021-01-20 Tatiana Mihaescu , Hermann Kampermann , Giulio Gianfelici , Aurelian Isar , Dagmar Bruss

Dynamics of entangled states of two independent single-mode cavities in squeezed reservoirs is investigated in the context of matching of the correlations contained in the entangled states to those contained in the squeezed reservoir. We…

Quantum Physics · Physics 2014-09-02 Khalid Aloufi , Smail Bougouffa , Zbigniew Ficek

Entanglement is one of the most striking features of quantum mechanics, and yet it is not specifically quantum. More specific to quantum mechanics is the connection between entanglement and thermodynamics, which leads to an identification…

Quantum Physics · Physics 2015-10-21 Giulio Chiribella , Carlo Maria Scandolo

We have experimentally realized the scheme initially proposed as quantum dense coding with continuous variables [Ban, J. Opt. B \textbf{1}, L9 (1999), and Braunstein and Kimble, \pra\textbf{61}, 042302 (2000)]. In our experiment, a pair of…

Quantum Physics · Physics 2007-05-23 Jun Mizuno , Kentaro Wakui , Akira Furusawa , Masahide Sasaki

We examine entanglement between number and polarization, or between number and relative phase, for pairs of coherent states and two-mode squeezed vacuum via linear entropy and covariance criteria. We consider the embedding of the two-mode…

Quantum Physics · Physics 2018-04-11 Carlos Sanchidrián-Vaca , Alfredo Luis

The fully symmetric Gaussian tripartite entangled pure states will not exhibit two-mode Einstein Podolsky-Rosen (EPR)-steering. This means that any two participants cannot share quantum secrets using the security of one-sided device…

Quantum Physics · Physics 2016-08-24 M. K. Olsen , E. G. Cavalcanti

We propose two probabilistic entanglement concentration schemes for a single copy of two-mode squeezed vacuum state. The first scheme is based on the off-resonant interaction of a Rydberg atom with the cavity field while the second setup…

Quantum Physics · Physics 2012-08-27 Jaromir Fiurasek , Ladislav Mista, , Radim Filip

We introduce a multi-mode squeezing coefficient to characterize entanglement in $N$-partite continuous-variable systems. The coefficient relates to the squeezing of collective observables in the $2N$-dimensional phase space and can be…

Quantum Physics · Physics 2017-07-17 Manuel Gessner , Luca Pezzè , Augusto Smerzi