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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

Homodyne measurement is a crucial tool widely used to address continuous variables for bosonic quantum systems. While an ideal homodyne detection provides a powerful analysis, e.g. to effectively measure quadrature amplitudes of light in…

Quantum Physics · Physics 2024-01-03 Jaehak Lee , Jiyong Park , Jaewan Kim , M. S. Kim , Hyunchul Nha

In general, a pair of uncorrelated Gaussian states mixed in a beam splitter produces a correlated state at the output. However, when the inputs are identical Gaussian states the output state is equal to the input, and no correlations…

Quantum Physics · Physics 2015-06-04 A. Meda , S. Olivares , I. P. Degiovanni , G. Brida , M. Genovese , M. G. A. Paris

Quantum non-Gaussianity is a key resource for quantum advantage in continuous-variable systems. We introduce a general framework to quantify non-Gaussianity based on correlation generation: two copies of a state become correlated at a…

Quantum Physics · Physics 2025-08-28 Oliver Hahn , Ryuji Takagi

Einstein-Podolsky-Rosen steering incarnates a useful nonclassical correlation which sits between entanglement and Bell nonlocality. While a number of qualitative steering criteria exist, very little has been achieved for what concerns…

Quantum Physics · Physics 2015-02-13 Ioannis Kogias , Antony R. Lee , Sammy Ragy , Gerardo Adesso

We address realistic schemes for the generation of non-Gaussian states of light based on conditional intensity measurements performed on correlated bipartite states. We consider both quantum and classically correlated states and different…

Genuine multimode entanglement in continuous variable systems can be quantified by exploring the geometry of the state-space, namely via the generalized geometric measure (GGM) which is defined as the shortest distance of a given multimode…

Quantum Physics · Physics 2020-07-22 Saptarshi Roy , Tamoghna Das , Aditi Sen De

We consider quantum steering by non-Gaussian entangled states. The Reid steering criterion based on the Heisenberg uncertainty relation fails to detect steerability for many categories of such states. Here, we derive a tighter steering…

Quantum Physics · Physics 2018-07-25 Souradeep Sasmal , Tanumoy Pramanik , Dipankar Home , A. S. Majumdar

We introduce a family of entanglement witnesses for continuous variable systems, which rely on the sole assumption that their dynamics is that of coupled harmonic oscillators at the time of the test. Entanglement is inferred from the…

Quantum Physics · Physics 2024-07-31 Pooja Jayachandran , Lin Htoo Zaw , Valerio Scarani

We develop an entanglement criterion with third- and fourth-order cumulants to detect the entanglement of non-Gaussian states. The efficiency of the entanglement criterion is investigated for gravitating mirrors in optomechanical systems.…

Quantum Physics · Physics 2022-01-26 Daisuke Miki , Akira Matsumura , Kazuhiro Yamamoto

We present a formalism to derive entanglement criteria beyond the Gaussian regime that can be readily tested by only homodyne detection. The measured observable is the Einstein-Podolsky-Rosen (EPR) correlation. Its arbitrary functional form…

Quantum Physics · Physics 2015-06-03 Hyunchul Nha , Su-Yong Lee , Se-Wan Ji , M. S. Kim

We introduce a new quantity for describing nonclassicality of an arbitrary optical two-mode Gaussian state which remains invariant under any global photon-number preserving unitary transformation of the covariance matrix of the state. The…

Quantum Physics · Physics 2016-07-08 Ievgen I. Arkhipov , Jan Peřina , Jiří Svozilík , Adam Miranowicz

The entanglement of general pure Gaussian two-mode states is examined in terms of the coefficients of the quadrature components of the wavefunction. The entanglement criterion and the entanglement of formation are directly evaluated as a…

Quantum Physics · Physics 2009-11-11 R. W. Rendell , A. K. Rajagopal

How to prepare deterministically non-Gaussian entangled states is a fundamental question for continuous-variable quantum information technology. Here, we theoretically demonstrate through numerical methods that the triple-photon state…

Quantum Physics · Physics 2021-01-13 D. Zhang , Y. Cai , Z. Zheng , D. Barral , Y. Zhang , M. Xiao , K. Bencheikh

Nonlinear squeezing is a property of non-Gaussian states of light with an important application in continuous variable quantum computing. We study the generation of nonlinear squeezing in multimode systems produced by the photon-added…

Quantum Physics · Physics 2025-05-15 Vojtěch Kala , Denis Kopylov , Petr Marek , Polina Sharapova

We derive a theoretical framework for the experimental certification of non-Gaussian features of quantum states using double homodyne detection. We rank experimental non-Gaussian states according to the recently defined stellar hierarchy…

The separability of bipartite non-Gaussian states is studied by applying the realignment criterion with the technique of functional analysis. The realignment criterion is given as one inequality in contrast to the infinitive number of…

Quantum Physics · Physics 2014-02-05 Xiao-yu Chen , Li-zhen Jiang , Ping Yu , Mingzhen Tian

Non-Gaussian operations are essential to exploit the quantum advantages in optical continuous variable quantum information protocols. We focus on mode-selective photon addition and subtraction as experimentally promising processes to create…

Quantum Physics · Physics 2017-11-08 Mattia Walschaers , Claude Fabre , Valentina Parigi , Nicolas Treps

We present an event-ready procedure that is capable of distilling Gaussian two-mode entangled states from a supply of weakly entangled states that have become mixed in a decoherence process. This procedure relies on passive optical elements…

Quantum Physics · Physics 2009-11-10 J. Eisert , D. E. Browne , S. Scheel , M. B. Plenio

We experimentally generate and tomographically characterize a mixed, genuinely non-Gaussian bipartite continuous-variable entangled state. By testing entanglement in 2$\times$2-dimensional two-qubit subspaces, entangled qubits are localized…

Quantum Physics · Physics 2015-03-17 T. Kiesel , W. Vogel , B. Hage , R. Schnabel