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Estimating quantum amplitude, or the overlap between two quantum states, is a fundamental task in quantum computing and underpins numerous quantum algorithms. In this work, we introduce a novel algorithmic framework for quantum amplitude…

Quantum Physics · Physics 2025-02-27 Zhong-Xia Shang , Qi Zhao

Finding the minimal relative entropy of two quantum states under semidefinite constraints is a pivotal problem located at the mathematical core of various applications in quantum information theory. An efficient method for providing…

Quantum Physics · Physics 2026-02-02 Gereon Koßmann , René Schwonnek

The von Neumann entropy of a graph is a spectral complexity measure that has recently found applications in complex networks analysis and pattern recognition. Two variants of the von Neumann entropy exist based on the graph Laplacian and…

Quantum Physics · Physics 2019-01-30 Giorgia Minello , Luca Rossi , Andrea Torsello

We introduce the concept of quantum supermap, describing the most general transformation that maps an input quantum operation into an output quantum operation. Since quantum operations include as special cases quantum states, effects, and…

Quantum Physics · Physics 2008-10-22 G. Chiribella , G. M. D'Ariano , P. Perinotti

Using the graphical calculus and integration techniques introduced by the authors, we study the statistical properties of outputs of products of random quantum channels for entangled inputs. In particular, we revisit and generalize models…

Quantum Physics · Physics 2012-02-17 Benoit Collins , Ion Nechita

Quantum states that possess negative conditional von Neumann entropy provide quantum advantage in several information-theoretic protocols including superdense coding, state merging, distributed private randomness distillation and one-way…

Quantum Physics · Physics 2021-07-22 Mahathi Vempati , Nirman Ganguly , Indranil Chakrabarty , Arun K Pati

We compare the entropy-energy inequality and the von Neumann entropic inequality for three level atom implemented on superconducting circuits with Josephson junction. The positivity of entropy and energy relations for the qutrit system are…

Quantum Physics · Physics 2016-08-08 V. I. Man'ko , L. A. Markovich

We introduce a series of quantities which characterizes a given local operator in conformal field theories from the viewpoint of quantum entanglement. It is defined by the increased amount of (Renyi) entanglement entropy at late time for an…

High Energy Physics - Theory · Physics 2014-03-26 Masahiro Nozaki , Tokiro Numasawa , Tadashi Takayanagi

Quantum physics, despite its observables being intrinsically of a probabilistic nature, does not have a quantum entropy assigned to them. We propose a quantum entropy that quantify the randomness of a pure quantum state via a conjugate pair…

Quantum Physics · Physics 2022-10-05 Davi Geiger , Zvi M. Kedem

By using relative entropy of coherence, we characterize the coherence gain induced by some quantum evolutions, including the cohering power of unitary operations and the decohering power of quantum operations. We find that the cohering…

Quantum Physics · Physics 2016-07-28 Zhengjun Xi , Mingliang Hu , Yongming Li , Heng Fan

We consider realistic measurement systems, where measurements are accompanied by decoherence processes. The aim of this work is the construction of methods and algorithms for precise quantum measurements with fidelity close to the…

Quantum Physics · Physics 2017-01-10 Yu. I. Bogdanov , B. I. Bantysh , N. A. Bogdanova , A. B. Kvasnyy , V. F. Lukichev

Linear maps that are not completely positive play a crucial role in the study of quantum information, yet their non-completely positive nature renders them challenging to realize physically. The core difficulty lies in the fact that when…

Quantum Physics · Physics 2025-08-19 Fuchuan Wei , Rundi Lu , Yuguo Shao , Junfeng Li , Jin-Peng Liu , Zhengwei Liu

Quantum filtering is a signal processing technique that estimates the posterior state of a quantum system under continuous measurements and has become a standard tool in quantum information processing, with applications in quantum state…

Quantum Physics · Physics 2014-08-19 Mankei Tsang

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 propose a new method to efficiently compute the entanglement entropy (EE) of quantum many-body systems. Our approach, called the incremental SWAP operator method , combines the simplicity of the SWAP operator used in projector quantum…

Strongly Correlated Electrons · Physics 2024-04-04 Xuan Zhou , Zi Yang Meng , Yang Qi , Yuan Da Liao

Observational entropy is interpreted as the uncertainty an observer making measurements associates with a system. So far, properties that make such an interpretation possible rely on the assumption of ideal projective measurements. We show…

Quantum Physics · Physics 2023-12-11 Dominik Šafránek , Juzar Thingna

The correspondence principle plays a fundamental role in quantum mechanics, which naturally leads us to inquire whether it is possible to find or determine close classical analogs of quantum states in phase space -- a common meeting point…

Quantum Physics · Physics 2022-01-28 A. S. Sanz

The kernel trick in supervised learning signifies transformations of an inner product by a feature map, which then restructures training data in a larger Hilbert space according to an endowed inner product. A quantum feature map corresponds…

Quantum Physics · Physics 2024-06-04 Hyeokjea Kwon , Hojun Lee , Joonwoo Bae

Quantitative analysis of discontinuity of basic characteristics of quantum states and channels is presented. First we consider general estimates for discontinuity jump (loss) of the von Neumann entropy for a given converging sequence of…

Quantum Physics · Physics 2021-09-28 M. E. Shirokov

Bipartite entanglement entropy is one of the most useful characterizations of universal properties in a many-body quantum system. Far from equilibrium, there exist two highly effective theories describing its dynamics -- the quasiparticle…

Statistical Mechanics · Physics 2025-08-20 Shachar Fraenkel , Colin Rylands