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Related papers: On the Bargmann invariants for quantum imaginarity

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In this paper, we introduce the framework for quantifying the imaginarity of quantum channels. Besides, an alternative framework is given together to simplify the process of verifying the condition. We present three imaginarity measures of…

Quantum Physics · Physics 2025-02-25 Xiangyu Chen , Qiang Lei

At present, quantum theory leaves unsettled which quantities ontologically, physically exist in a quantum system. Do observables such as energy and position have meaningful values only at the precise moment of measurement, as in the…

Quantum Physics · Physics 2018-11-26 Brendan Marsh

Quantum entanglement, crucial for understanding quantum many-body systems and quantum gravity, is commonly assessed through various measures such as von Neumann entropy, mutual information, and entanglement contour, each with its inherent…

Quantum Physics · Physics 2025-07-08 Liang-Hong Mo , Yao Zhou , Jia-Rui Sun , Peng Ye

Subsystems of composite quantum systems are described by reduced density matrices, or quantum marginals. Important physical properties often do not depend on the whole wave function but rather only on the marginals. Not every collection of…

Quantum Physics · Physics 2014-10-31 Michael Walter

It is argued that a realistic interpretation of quantum mechanics is possible and useful. Current interpretations, from Copenhagen to many worlds are critically revisited. The difficulties for intuitive models of quantum physics are pointed…

Quantum Physics · Physics 2017-01-11 Emilio Santos

The concept of \textquotedblleft the permutationally invariant part of a density matrx\textquotedblright constitutes an important tool for entanglement characterization of multiqubit systems. In this paper, we first present $(k+1)$-partite…

Quantum Physics · Physics 2024-01-18 Yan Hong , Xianfei Qi , Ting Gao , Fengli Yan

Hamiltonian of a system in quantum field theory can give rise to infinitely many partition functions which correspond to infinitely many inequivalent representations of the canonical commutator or anticommutator rings of field operators.…

Quantum Physics · Physics 2015-06-26 Michal Matejka , Milan Noga

Recently, the basic concept of quantum coherence (or superposition) has gained a lot of renewed attention, after Baumgratz et al. [PRL 113:140401 (2014)], following \AA{}berg [arXiv:quant-ph/0612146], have proposed a resource theoretic…

Quantum Physics · Physics 2017-08-01 Tanmoy Biswas , María García Díaz , Andreas Winter

We report the creation of a wide range of quantum states with controllable degrees of entanglement and entropy using an optical two-qubit source based on spontaneous parametric downconversion. The states are characterised using measures of…

Quantum Physics · Physics 2009-11-07 A. G. White , D. F. V. James , W. J. Munro , P. G. Kwiat

We develop a rigorous connection between statistical properties of an interference pattern and the coherence properties of the underlying quantum state. With explicit examples, we demonstrate that even for inaccurate reconstructions of…

Quantum Physics · Physics 2015-11-25 Kai von Prillwitz , Łukasz Rudnicki , Florian Mintert

The traditional view from particle physics is that quantum gravity effects should only become detectable at extremely high energies and small length scales. Due to the significant technological challenges involved, there has been limited…

Many physicists limit oneself to an instrumentalist description of quantum phenomena and ignore the problems of foundation and interpretation of quantum mechanics. This instrumentalist approach results to "specialization barbarism" and mass…

General Physics · Physics 2010-07-13 V. V. Aristov , A. V. Nikulov

Genuine multipartite entanglement underlies correlation experiments corroborating quantum mechanics and it is an expedient empowering many quantum technologies. One of many counterintuitive facets of genuine multipartite entanglement is its…

The Wigner's friend type of thought experiments manifest the conceptual challenge on how different observers can have consistent descriptions of a quantum measurement event. In this paper, we analyze the extended version of Wigner's friend…

Quantum Physics · Physics 2019-11-12 Jianhao M. Yang

This paper introduces the quantum deep sets model, expanding the quantum machine learning tool-box by enabling the possibility of learning variadic functions using quantum systems. A couple of variants are presented for this model. The…

Quantum Physics · Physics 2025-06-13 Vladimir Vargas-Calderón

Neural-network state representations of quantum many-body systems are attracting great attention and more rigorous quantitative analysis about their expressibility and complexity is warranted. Our analysis of the restricted Boltzmann…

Quantum Physics · Physics 2024-05-24 Ruizhi Pan , Charles W. Clark

We take a tour of a set of equiangular lines in eight-dimensional Hilbert space. This structure defines an informationally complete measurement, that is, a way to represent all quantum states of three-qubit systems as probability…

Quantum Physics · Physics 2016-09-13 Blake C. Stacey

We analyze a basis-independent definition of quantum coherence. The maximally mixed state is used as the reference state, which allows for a way of defining coherence that is invariant under arbitrary unitary transformations. The…

Quantum Physics · Physics 2019-09-04 Chandrashekar Radhakrishnan , Zhe Ding , Fazhan Shi , Jiangfeng Du , Tim Byrnes

Quantum entanglement and coherence are crucial resources in quantum information theory. In some scenarios, however, it is not necessary to directly estimate entanglement or coherence measures to quantify the capabilities of a state in…

Quantum Physics · Physics 2025-11-11 Si-Qi Zhou , Jin-Min Liang , Jiayin Peng , Zhihua Chen , Shao-Ming Fei , Zhihao Ma

Numerical stochastic integration is a powerful tool for the investigation of quantum dynamics in interacting many body systems. As with all numerical integration of differential equations, the initial conditions of the system being…

Quantum Gases · Physics 2015-05-13 M. K. Olsen , A. S. Bradley