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We introduce the general parameter Q_PB that provides an experimentally accessible nonclassicality measure for light. The parameter is quantified by the click statistics obtained from on-off detectors in a general multiplexing detection…

Quantum Physics · Physics 2016-11-28 Changhyoup Lee , Simone Ferrari , Wolfram H. P. Pernice , Carsten Rockstuhl

Non-Gaussianity inducing operations are studied in the recent past from different perspectives. Here, we study the role of photon addition, a non-Gaussianity inducing operation, in the enhancement of nonclassicality in a finite dimensional…

Quantum Physics · Physics 2022-06-10 Priya Malpani , Kishore Thapliyal , Anirban Pathak

In this report we are aiming at introducing a global measure of non-classicality of the state space of $N$-level quantum systems and estimating it in the limit of large $N$. For this purpose we employ the Wigner function negativity as a…

Quantum Physics · Physics 2021-12-30 Vahagn Abgaryan , Arsen Khvedelidze , Ilya Rogojin

We suggest an optical method which tests a nonclassical feature with a coherent state input. The test is designed with a multiplexer of on/off detectors and post-selection, adopting sub-binomiality as a nonclassical feature, replacing…

Quantum Physics · Physics 2016-09-28 Jeongwoo Jae , Kang Hee Seol , Kwang-Geol Lee , Jinhyoung Lee

Entanglement is one of the pillars of quantum mechanics and quantum information processing, and as a result the quantumness of nonentangled states has typically been overlooked and unrecognized. We give a robust definition for the…

Quantum Physics · Physics 2007-05-23 Berry Groisman , Dan Kenigsberg , Tal Mor

Non-Gaussian states of light are essential for numerous quantum information protocols; thus, certifying non-Gaussianity is crucial. Full quantum state tomography, commonly used for this purpose, is a complicated procedure and yields…

A unified conceptual foundation of classical and quantum physics is given, free of undefined terms. Ensembles are defined by extending the `probability via expectation' approach of Whittle to noncommuting quantities. This approach carries…

Quantum Physics · Physics 2007-05-23 Arnold Neumaier

The lack of information obtained from informationally incomplete quantum measurements can prevent the detection of quantum resources, such as optical nonclassicality. We develop a technique that overcomes this limitation for single-mode…

Quantum Physics · Physics 2025-05-07 V. S. Kovtoniuk , A. B. Klimov , A. A. Semenov

Practically applicable criteria for the nonclassicality of quantum states are formulated in terms of different types of moments. For this purpose the moments of the creation and annihilation operators, of two quadratures, and of a…

Quantum Physics · Physics 2009-11-11 E. V. Shchukin , W. Vogel

We experimentally verify the quantum non-Gaussian character of a conditionally generated noisy squeezed single-photon state with positive Wigner function. Employing an optimized witness based on probabilities of squeezed vacuum and squeezed…

Quantum Physics · Physics 2013-05-30 M. Jezek , A. Tipsmark , R. Dong , J. Fiurasek , L. Mista , R. Filip , U. L. Andersen

State smoothing is a technique to estimate a state at a particular time, conditioned on information obtained both before (past) and after (future) that time. For a classical system, the smoothed state is a normalized product of the…

Quantum Physics · Physics 2024-04-04 Kiarn T. Laverick , Prahlad Warszawski , Areeya Chantasri , Howard M. Wiseman

We calculate exactly the quantum mechanical, temporal Wigner quasiprobability density for a single-mode, degenerate parametric amplifier for a system in the Gaussian state, viz., a displaced-squeezed thermal state. The Wigner function…

Quantum Physics · Physics 2021-03-16 Moorad Alexanian

Several definitions of classicality are considered, such as P-representability, generalized coherent states and separable states. These notions are treated under a simple and general definition based on convex sets, which enables the use of…

Quantum Physics · Physics 2012-04-10 F. E. S. Steinhoff

The connection between coarse-graining of measurement and emergence of classicality has been investigated for some time, if not well understood. Recently in (PRL $\textbf{112}$, 010402, (2014)) it was pointed out that coarse-graining…

Quantum Physics · Physics 2017-03-03 Madhav Krishnan , Tanmoy Biswas , Sibasish Ghosh

A non-Gaussian state being a mixture of the vacuum and single-photon states can be generated by truncating a thermal state in a quantum scissors device of Pegg et al. [Phys. Rev. Lett. 81 (1998) 1604]. In contrast to the thermal state, the…

Quantum Physics · Physics 2016-08-24 Hong-xia Zhao , Xue--xiang Xu , Hong-chun Yuan

A number of noncontextual models exist which reproduce different subsets of quantum theory and admit a no-cloning theorem. Therefore, if one chooses noncontextuality as one's notion of classicality, no-cloning cannot be regarded as a…

Quantum Physics · Physics 2020-04-29 Matteo Lostaglio , Gabriel Senno

We address the issue of quantifying the non-Gaussian character of a bosonic quantum state and introduce a non-Gaussianity measure based on the Hilbert-Schmidt distance between the state under examination and a reference Gaussian state. We…

Quantum Physics · Physics 2009-11-13 Marco G. Genoni , Matteo G. A. Paris , Konrad Banaszek

We consider Gaussian quantum circuits supplemented with non-Gaussian input states and derive sufficient conditions for efficient classical strong simulation of these circuits. In particular, we generalise the stellar representation of…

Quantum Physics · Physics 2021-07-14 Ulysse Chabaud , Giulia Ferrini , Frédéric Grosshans , Damian Markham

The general problem of performance advantage obtainable by the use of nonclassical transmitted states over classical ones is considered. Attention is focused on the situation where system loss is significant and additive Gaussian noise may…

Quantum Physics · Physics 2012-12-05 Horace P. Yuen , Ranjith Nair

The collapse of a quantum state can be understood as a mathematical way to construct a joint probability density even for operators that do not commute. We can formalize that construction as a non-commutative, non-associative collapse…

Quantum Physics · Physics 2022-06-13 Peter Morgan