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Entanglement is a key resource for many quantum applications. Understanding fundamental properties of entangled states is an important step towards their practical exploitation. We characterize entanglement in the context of Gaussian and…

Quantumness and separability criteria for continuous variable systems are discussed for the case of a noncommutative (NC) phase-space. In particular, the quantum nature and the entanglement configuration of NC two-mode Gaussian states are…

Quantum Physics · Physics 2015-10-13 Alex E. Bernardini , Catarina Bastos , Orfeu Bertolami , Nuno C. Dias , João N. Prata

With the goal of gaining a deeper understanding of quantum non-locality, we decompose quantum correlations into more elementary non-local correlations. We show that the correlations of all pure entangled states of two qubits can be…

Quantum Physics · Physics 2009-11-13 Nicolas Brunner , Nicolas Gisin , Sandu Popescu , Valerio Scarani

We draw an explicit connection between the statistical properties of an entangled two-mode continuous variable (CV) resource and the amount of entanglement that can be dynamically transferred to a pair of non-interacting two-level systems.…

Quantum Physics · Physics 2015-05-13 Mauro Paternostro , Gerardo Adesso , Steve Campbell

We explore the effect of two-dimensional position-space non-commutativity on the bipartite entanglement of continuous variable systems. We first extend the standard symplectic framework for studying entanglement of Gaussian states of…

Quantum Physics · Physics 2013-05-29 S. Adhikari , B. Chakraborty , A. S. Majumdar , S. Vaidya

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

Continuous variable entanglement is a manifestation of nonclassicality of quantum states. In this paper we attempt to analyze whether and under which conditions nonclassicality can be used as an entanglement criterion. We adopt the…

Quantum Physics · Physics 2009-05-15 Petr Marek , M. S. Kim , Jinhyoung Lee

We propose a protocol for coherently transferring non-Gaussian quantum states from optical field to a mechanical oscillator. The open quantum dynamics and continuous-measurement process, which can not be treated by the…

Quantum Physics · Physics 2013-05-29 Farid Khalili , Stefan Danilishin , Haixing Miao , Helge Muller-Ebhardt , Huan Yang , Yanbei Chen

The behavior of general nonclassical two-mode Gaussian states at a beam splitter is investigated. Single-mode nonclassicality as well as two-mode entanglement of both input and output states are analyzed suggesting their suitable…

Quantum Physics · Physics 2016-07-07 Ievgen I. Arkhipov , Jan Peřina , Jan Peřina , Adam Miranowicz

We study how the number of employed modes impacts the ability to witness non-Markovian evolutions via correlation backflows in continuous-variable quantum dynamics. We first prove the existence of non-Markovian Gaussian evolutions that do…

Quantum Physics · Physics 2023-03-01 Dario De Santis , Donato Farina , Mohammad Mehboudi , Antonio Acín

Repeated measurements can induce entanglement phase transitions in the dynamics of quantum systems. Interacting models, both chaotic and integrable, generically show a stable volume-law entangled phase at low measurement rates which…

Quantum Physics · Physics 2024-05-21 Luca Lumia , Emanuele Tirrito , Rosario Fazio , Mario Collura

The measurement of dynamic correlation functions of quantum systems is complicated by measurement backaction. To facilitate such measurements we introduce a protocol, based on weak ancilla--system couplings, that is applicable to arbitrary…

Quantum Physics · Physics 2017-08-23 Philipp Uhrich , Salvatore Castrignano , Hermann Uys , Michael Kastner

Activation of quantum capacity is a surprising phenomenon according to which the quantum capacity of a certain channel may increase by combining it with another channel with zero quantum capacity. Superactivation describes an even more…

Quantum Physics · Physics 2019-03-29 Youngrong Lim , Ryuji Takagi , Gerardo Adesso , Soojoon Lee

The relation between genuine multipartite entanglement in the pure state of a collection of N qubits and the nonclassical correlations in its two-qubit subsystems is studied. Quantum discord is used as the quantifier of nonclassical…

Quantum Physics · Physics 2022-08-31 Chandan Mahto , Vijay Pathak , Ardra K. S. , Anil Shaji

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 investigate the continuous-variable entanglement swapping protocol in a non-Gaussian setting, with non- Gaussian states employed either as entangled inputs and/or as swapping resources. The quality of the swapping protocol is assessed in…

Quantum Physics · Physics 2021-10-26 F. Dell'Anno , D. Buono , G. Nocerino , S. De Siena , F. Illuminati

Quantum discord, a measure of genuinely quantum correlations, is generalized to continuous variable systems. For all two-mode Gaussian states, we calculate analytically the quantum discord and a related measure of classical correlations,…

Quantum Physics · Physics 2015-03-13 Gerardo Adesso , Animesh Datta

Non-Gaussian entangled states play a crucial role in harnessing quantum advantage in continuous-variable quantum information. However, how to fully characterize N-partite (N > 3) non-Gaussian entanglement without quantum state tomography…

Quantum Physics · Physics 2023-12-05 Da Zhang , David Barral , Yanpeng Zhang , Kamel Bencheikh

Entanglement of quasiclassical (coherent) states of two harmonic oscillators leads to striking quantum effects and is useful for quantum technologies. These effects and applications are closely related to nonlocal correlations inherent in…

Quantum Physics · Physics 2019-05-14 Zhi-Rong Zhong , Jian-Qi Sheng , Li-Hua Lin , Shi-Biao Zheng

It is widely spread in the literature that non-Markovianity (NM) may be regarded as a resource in quantum mechanics. However, it is still unclear how and when this alleged resource may be exploited. Here, we study the relationship between…

Quantum Physics · Physics 2019-03-19 Nicolás Mirkin , Pablo Poggi , Diego Wisniacki