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Related papers: Signatures of nonclassical effects in tomograms

200 papers

Entanglement is a non local property of quantum states which has no classical counterpart and plays a decisive role in quantum information theory. Several protocols, like the teleportation, are based on quantum entangled states. Moreover,…

Logic in Computer Science · Computer Science 2008-12-08 Simon Perdrix

We show how entanglement can be used to improve the estimation of an unknown transformation. Using entanglement is always of benefit, in improving either the precision or the stability of the measurement. Examples relevant for applications…

Quantum Physics · Physics 2019-05-15 G. Mauro D'Ariano , Paoloplacido Lo Presti , Matteo G. A. Paris

Quantification of nonclassicality and entanglement in a quantum state is crucial for quantum advantage in information processing and computation. Robustness is one of the tractable measures for quantifying quantum resources. Gaussian states…

Quantum Physics · Physics 2023-09-22 Xiao-yu Chen

We characterize entanglement subject to its definition over real and complex, composite quantum systems. In particular, a method is established to assess quantum correlations with respect to a selected number system, illuminating the deeply…

Recent progress in theories of quantum information has determined nonclassical correlation defined differently from widely-used entanglement as an important property to evaluate computation and communication with mixed quantum states. We…

Quantum Physics · Physics 2010-08-13 Robabeh Rahimi , Akira SaiToh

The significance of the quantum feature of entanglement between physical systems is investigated in the context of quantum measurements. It is shown that, while there are measurement couplings that leave the object and probe systems…

Quantum Physics · Physics 2011-01-04 P. Busch

Nonclassical states are essential for optics-based quantum information processing, but their fragility limits their utility for practical scenarios in which loss and noise inevitably degrade, if not destroy, nonclassicality. Exploiting…

Quantum Physics · Physics 2015-03-25 Zheshen Zhang , Sara Mouradian , Franco N. C. Wong , Jeffrey H. Shapiro

We suggest a general scheme for quantum state engineering based on conditional measurements carried out on entangled twin-beam of radiation. Realistic detection schemes such as {\sc on/off} photodetection, homodyne detection and joint…

Quantum Physics · Physics 2009-11-07 Matteo G. A. Paris , Mary Cola , Rodolfo Bonifacio

Although the foundations of quantum and classical physics are much different, it is often difficult to pinpoint which features of a particular system are intrinsically "quantum". Perhapse, the most clear-cut distinction between "classical"…

Quantum Physics · Physics 2015-02-05 Piotr Szańkowski

Tomographic reconstruction of quantum states plays a fundamental role in benchmarking quantum systems and accessing information encoded in quantum-mechanical systems. Among the informationally complete sets of quantum measurements, the…

Quantum Physics · Physics 2025-06-11 Victor Gonzalez Avella , Jakub Czartowski , Dardo Goyeneche , Karol Życzkowski

The quantum mechanics formalism introduced new revolutionary concepts challenging our everyday perceptions. Arguably, quantum entanglement, which explains correlations that cannot be reproduced classically, is the most notable of them.…

Symmetric quantum states are fascinating objects. They correspond to multipartite systems that remain invariant under particle permutations. This symmetry is reflected in their compact mathematical characterisation but also in their unique…

Quantum Physics · Physics 2025-07-15 Carlo Marconi , Guillem Müller-Rigat , Jordi Romero-Pallejà , Jordi Tura , Anna Sanpera

A review of the tomographic-probability representation of classical and quantum states is presented. The tomographic entropies and entropic uncertainty relations are discussed in connection with ambiguities in the interpretation of the…

Quantum Physics · Physics 2015-06-11 Margarita A. Man'ko , Vladimir I. Man'ko

Quantum tomography is a process of quantum state reconstruction using data from multiple measurements. An essential goal for a quantum tomography algorithm is to find measurements that will maximize the useful information about an unknown…

Quantum Physics · Physics 2020-08-05 A. D. Moiseevskiy , G. I. Struchalin , S. S. Straupe , S. P. Kulik

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

Quantum entanglement reflects itself through non-local correlations among the subsystems of a quantum system. This thesis focuses on constructing a complete set of local invariants characterizing symmetric two qubit systems and analyzing…

Quantum Physics · Physics 2009-07-14 M. S. Uma

In a recent work, arXiv:2503.05884, we proposed a unified notion of nonclassicality that applies to arbitrary processes in quantum theory, including individual quantum states, measurements, channels, set of these, etc. This notion is…

Quantum Physics · Physics 2025-04-07 Yujie Zhang , Yìlè Yīng , David Schmid

We propose a tomographic approach to study quantum nonlocality in continuous variable quantum systems. On one hand we derive a Bell-like inequality for measured tomograms. On the other hand, we introduce pseudospin operators whose…

Quantum Physics · Physics 2009-11-10 Stefano Mancini , Vladimir I. Man'ko , Evgeny V. Shchukin , Paolo Tombesi

Quantum entanglement plays a crucial role in quantum information processing tasks and quantum mechanics, hence quantifying unknown entanglement is a fundamental task. However, this is also challenging, as entanglement cannot be measured by…

Quantum Physics · Physics 2021-04-27 Xiaodie Lin , Zhenyu Chen , Zhaohui Wei

Quantum mechanics exhibits a wide range of nonclassical features, of which entanglement in multipartite systems takes a central place. In several specific settings, it is well known that nonclassicality (e.g., squeezing, spin squeezing,…

Quantum Physics · Physics 2016-02-25 Nathan Killoran , Frank E. S. Steinhoff , Martin B. Plenio