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Entanglement is a cornerstone in quantum information science, yet detecting it efficiently remains a challenging task. Focusing on non-positive partially transposed (NPT) states, we establish a hierarchy among entropy-based, majorization,…

Quantum Physics · Physics 2025-07-30 Akhil Kumar Awasthi , Sudipta Mondal , Rivu Gupta , Aditi Sen De

We introduce the definition of generic bound entanglement for the case of continuous variables. We provide some examples of bound entangled states for that case, and discuss their physical sense in the context of quantum optics. We rise the…

Quantum Physics · Physics 2009-11-06 Pawel Horodecki , Maciej Lewenstein

Currently available separability criteria for continuous-variable states are generally based on the covariance matrix of quadrature operators. The well-known separability criterion of Duan et al. [Phys. Rev. Lett. 84, 2722 (2000)] and Simon…

Quantum Physics · Physics 2016-03-24 Anaelle Hertz , Evgueni Karpov , Aikaterini Mandilara , Nicolas J. Cerf

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

We outline the basic questions that are being studied in the theory of entanglement. Following a brief review of some of the main achievements of entanglement theory for finite-dimensional quantum systems such as qubits, we will consider…

Quantum Physics · Physics 2009-09-29 J. Eisert , M. B. Plenio

We derive a general criterion to detect entangled states in multi-partite systems based on the symmetric logarithmic derivative quantum Fisher information. This criterion is a direct consequence of the fact that separable states do not…

Quantum Physics · Physics 2016-10-12 Jun Suzuki

For continuous-variable systems, we introduce a measure of entanglement, the continuous variable tangle ({\em contangle}), with the purpose of quantifying the distributed (shared) entanglement in multimode, multipartite Gaussian states.…

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

We present conditions every measure of entanglement has to satisfy and construct a whole class of 'good' entanglement measures. The generalization of our class of entanglement measures to more than two particles is straightforward. We…

Quantum Physics · Physics 2009-01-23 V. Vedral , M. B. Plenio , M. A. Rippin , P. L. Knight

A general and computable criterion for k-(in)separability in continuous multipartite quantum systems is presented. The criterion can be experimentally implemented with a finite and comparatively low number of local observables. We discuss…

Quantum Physics · Physics 2012-02-07 Andreas Gabriel , Marcus Huber , Sasa Radic , Beatrix C. Hiesmayr

Dicke states are a family of multi-qubit quantum states with interesting entanglement properties and have been observed in many experiments. We construct entanglement witnesses for detecting genuine multiparticle entanglement in the…

Quantum Physics · Physics 2013-09-13 Marcel Bergmann , Otfried Gühne

We discuss the entropic criterion for separability of compound quantum systems for general non-additive entropic forms based on arbitrary concave functions $f$. For any separable state, the generalized entropy of the whole system is shown…

Quantum Physics · Physics 2015-05-20 R. Rossignoli , N. Canosa

We propose entanglement criteria for multipartite systems via symmetric informationally complete (SIC) measurement and general symmetric informationally complete (GSIC) measurement. We apply these criteria to detect entanglement of…

Quantum Physics · Physics 2021-12-22 Jun Li , Lin Chen

The entanglement produced by a bilinear Hamiltonian in continuous variables has been thoroughly studied and widely used. In contrast, the physics of entanglement resulting from nonlinear interaction described by partially degenerate…

Quantum Physics · Physics 2021-11-10 Da Zhang , David Barral , Yin Cai , Yanpeng Zhang , Min Xiao , Kamel Bencheikh

We derive a general framework to identify genuinely multipartite entangled mixed quantum states in arbitrary-dimensional systems and show in exemplary cases that the constructed criteria are stronger than those previously known. Our…

Quantum Physics · Physics 2013-05-29 Marcus Huber , Florian Mintert , Andreas Gabriel , Beatrix C. Hiesmayr

We introduce an entanglement criterion to exclude full separability of quantum states. We present numerical evidence that the criterion is necessary and sufficient for the class of GHZ diagonal three-qubit states and estimate the volume of…

Quantum Physics · Physics 2011-01-04 Otfried Gühne

First, we show how the quantum circuits for generating and measuring multi-party entanglement of qubits can be translated to continuous quantum variables. We derive sufficient inseparability criteria for $N$-party continuous-variable states…

Quantum Physics · Physics 2007-05-23 Peter van Loock , Samuel L. Braunstein

Entanglement is widely considered the cornerstone of quantum information and an essential resource for relevant quantum effects, such as quantum teleportation, quantum cryptography, or the speed-up of quantum computing, as in Shor's…

Quantum Physics · Physics 2017-01-13 M. Sanz , I. L. Egusquiza , R. Di Candia , H. Saberi , L. Lamata , E. Solano

Finite tight frames play an important role in miscellaneous areas, including quantum information theory. Here we apply a class of tight frames, equiangular tight frames, to address the problem of detecting the entanglement of bipartite…

Quantum Physics · Physics 2023-07-19 Xian Shi

We present an entanglement criterion for multiqubits by using the quantum correlation tensors which rely on the expectation values of the Pauli operators for a multiqubit state. Our criterion explains not only the total entanglement of the…

Quantum Physics · Physics 2007-05-23 Hyuk-jae Lee , Sung Dahm Oh , Doyeol Ahn

We study separability problem using general symmetric informationally complete measurements and propose separability criteria in $\mathbb{C}^{d_{1}}\otimes\mathbb{C}^{d_{2}}$ and…

Quantum Physics · Physics 2019-03-19 Ya Xi , Zhu-Jun Zheng , Chuan-Jie Zhu