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We develop a general framework to assess capabilities and limitations of the Gaussian toolbox in continuous variable quantum information theory. Our framework allows us to characterize the structure and properties of quantum resource…

Quantum Physics · Physics 2018-09-05 Ludovico Lami , Bartosz Regula , Xin Wang , Rosanna Nichols , Andreas Winter , Gerardo Adesso

We study the properties of bi-squeezed tripartite Gaussian states created by two spontaneous parametric down-conversion processes that share a common idler. We give a complete description of the quantum correlations across of all…

Quantum Physics · Physics 2017-06-23 David Edward Bruschi , Carlos Sabín , Gheorghe Sorin Paraoanu

Two-mode squeezed states are scalable and robust entanglement resources for continuous-variable and hybrid quantum information protocols at a distance. We consider the effect of a linear cross talk in the multimode distribution of two-mode…

Quantum Physics · Physics 2021-11-02 Olena Kovalenko , Vladyslav C. Usenko , Radim Filip

We present a study of the entanglement properties of Gaussian cluster states, proposed as a universal resource for continuous-variable quantum computing. A central aim is to compare mathematically-idealized cluster states defined using…

Quantum Physics · Physics 2010-11-30 Hugo Cable , Daniel E. Browne

We show that quantum entanglement can provide an exponential advantage in learning properties of a bosonic continuous-variable (CV) system. The task we consider is estimating a probabilistic mixture of displacement operators acting on $n$…

We review the theory of continuous-variable entanglement with special emphasis on foundational aspects, conceptual structures, and mathematical methods. Much attention is devoted to the discussion of separability criteria and entanglement…

Quantum Physics · Physics 2009-07-02 Gerardo Adesso , Fabrizio Illuminati

We generalise the Gaussian formalism of Continuous Variable (CV) systems to describe their interactions with qubits/qudits that result in quantum superpositions of Gaussian processes. To this end, we derive a new set of equations in closed…

Quantum Physics · Physics 2025-10-02 Lorenzo Braccini , Sougato Bose , Alessio Serafini

The correlation dynamics is investigated for various bi-partitions of a composite system consisting of two qubits, and two independent and non-identical noisy environments. The two qubits have no direct interaction with each other and…

Quantum Physics · Physics 2015-05-20 Xiu-xing Zhang , Fu-li Li

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 investigate the role of quadrature squeezing in the quantum teleportation protocol for coherent states, using non-Gaussian resource states. For the two-mode systems, the non-Gaussian resource states that we use are obtained by an…

Quantum Physics · Physics 2025-02-25 Mohak Sharma , Chandan Kumar , Shikhar Arora , Arvind

We consider the task of learning quantum states in bosonic continuous-variable (CV) systems. We present an experimentally feasible protocol that uses entangled measurements and reflected states to efficiently learn, up to sign, the…

Quantum Physics · Physics 2025-12-17 Eugen Coroi , Changhun Oh

Gaussian states are the backbone of quantum information protocols with continuous variable systems, whose power relies fundamentally on the entanglement between the different modes. In the case of global pure states, knowledge of the…

Quantum Physics · Physics 2017-11-08 Fernando Nicacio , Andrea Valdés-Hernández , Ana P. Majtey , Fabricio Toscano

We consider a quantum relay which is used by two parties to perform several continuous-variable protocols of quantum communication, from entanglement distribution (swapping and distillation), to quantum teleportation, and quantum key…

Entanglement of spatially separated quantum states is usually defined with respect to a reference frame provided by some external observer. Thus, if one wishes to localize the quantum information within a spatially separated entangled…

Quantum Physics · Physics 2023-07-05 Adam Dukehart , David Mattingly

A characteristic function (CF) based formalism for the representation of quantum optical operations pertaining to the Continuous Variable (CV) quantum teleportation protocol for general resource and input states is introduced; allowing for…

Quantum Physics · Physics 2009-04-01 L. Albano Farias

Very recently we have witnessed a new development of quantum information, the so-called continuous variable (CV) quantum information theory. Such a further development has been mainly due to the experimental and theoretical advantages…

Quantum Physics · Physics 2008-06-27 Stefano Pirandola , Stefano Mancini

Any kind of quantum resource useful in different information processing tasks is vulnerable to several types of environmental noise. Here we study the behaviour of quantum correlations such as entanglement and steering in two-qubit systems…

Quantum Physics · Physics 2021-01-13 Suchetana Goswami , Sibasish Ghosh , A. S. Majumdar

Quantum networks (QNs) have been predominantly driven by discrete-variable (DV) architectures. Yet, optical platforms naturally generate Gaussian states--the common states of continuous-variable (CV) systems, making CV-based QNs an…

Quantum Physics · Physics 2026-03-11 Yaqi Zhao , Kan He , Yongtao Zhang , Jinchuan Hou , Jianxi Gao , Shlomo Havlin , Xiangyi Meng

In this chapter we review the characterization of entanglement in Gaussian states of continuous variable systems. For two-mode Gaussian states, we discuss how their bipartite entanglement can be accurately quantified in terms of the global…

Quantum Physics · Physics 2007-05-23 Gerardo Adesso , Fabrizio Illuminati

Quantum information processing protocols are efficiently implemented on spin-$\frac{1}{2}$ networks. A quantum communication protocol generally involves a certain number of parties having local access to a subset of a larger system, whose…

Quantum Physics · Physics 2021-12-17 S. Lorenzo , F. Plastina , M. Consiglio , T. J. G. Apollaro