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We show that multipartite quantum states that have a positive partial transpose with respect to all bipartitions of the particles can outperform separable states in linear interferometers. We introduce a powerful iterative method to find…

Quantum Physics · Physics 2025-04-01 Géza Tóth , Tamás Vértesi

The initialization of a quantum system into a certain state is a crucial aspect of quantum information science. While a variety of measurement strategies have been developed to characterize how well the system is initialized, for a given…

We present separability criteria for both bipartite and multipartite quantum states. These criteria include the criteria based on the correlation matrix and its generalized form as special cases. We show by detailed examples that our…

Quantum Physics · Physics 2014-02-19 Ming Li , Jing Wang , Shao-Ming Fei , Xianqing Li-Jost

This work presents a machine learning approach based on support vector machines (SVMs) for quantum entanglement detection. Particularly, we focus in bipartite systems of dimensions 3x3, 4x4, and 5x5, where the positive partial transpose…

We explore the effect of two-dimensional position-space non-commutativity on the bipartite entanglement of continuous variable systems. We first extend the standard symplectic framework for studying entanglement of Gaussian states of…

Quantum Physics · Physics 2013-05-29 S. Adhikari , B. Chakraborty , A. S. Majumdar , S. Vaidya

We provide a generalized treatment of uncertainties, von Neumann entropy, and squeezing in entangled bipartite pure state of two-level atoms. We observe that when the bipartite state is entangled, though the von Neumann entropy of the…

Quantum Physics · Physics 2025-06-04 Ram Narayan Deb

We ask whether the optimal probe is entangled, and if so, what is its character and amount, for estimating the noise parameter of a large class of local quantum encoding processes that we refer to as vector encoding, examples of which…

Quantum Physics · Physics 2026-04-23 Shuva Mondal , Priya Ghosh , Ujjwal Sen

A definition of the nonadditive (nonextensive) conditional entropy indexed by q is presented. Based on the composition law in terms of it, the Shannon-Khinchin axioms are generalized and the uniqueness theorem is established for the Tsallis…

Quantum Physics · Physics 2007-05-23 Sumiyoshi Abe , A. K. Rajagopal

Developing reliable methods for certifying the dimension of a given quantum system or process is essential to ensure the validity of claimed realization of high-dimensional (HD) quantum advantages. The existing criteria for certifying…

Optics · Physics 2026-05-13 Neng-Fei Gong , Tie-Jun Wang

We introduce a new entanglement measure based on optimal entanglement witness. First of all, we show that the entanglement measure satisfies some necessary properties, including zero entanglements for all separable states, convexity,…

Quantum Physics · Physics 2024-02-20 Nan Yang , Jiaji Wu , Xianyun Dong , Longyu Xiao , Jing Wang , Ming Li

Entanglement, and quantum correlation, are precious resources for quantum technologies implementation based on quantum information science, such as, for instance, quantum communication, quantum computing, and quantum interferometry.…

Quantum Physics · Physics 2023-05-22 Arthur Vesperini , Ghofrane Bel-Hadj-Aissa , Roberto Franzosi

We construct a density matrix whose elements are written in terms of expectation values of non-Hermitian operators and their products for arbitrary dimensional bipartite states. We then show that any expression which involves matrix…

Quantum Physics · Physics 2015-06-23 N. Ananth , V. K. Chandrasekar , M. Senthilvelan

We consider random bipartite quantum states obtained by tracing out one subsystem from a random, uniformly distributed, tripartite pure quantum state. We compute thresholds for the dimension of the system being traced out, so that the…

Mathematical Physics · Physics 2015-09-23 Maria Anastasia Jivulescu , Nicolae Lupa , Ion Nechita

Recently, a new and powerful separability criterion was introduced in [O. Rudolph, quant-ph/0202121] and [Chen {\it et al.}, quant-ph/0205017]. Composing the main idea behind the above criterion and the necessary and sufficient condition in…

Quantum Physics · Physics 2007-05-23 Michal Horodecki , Pawel Horodecki , Ryszard Horodecki

We investigate generalized measurements, based on positive-operator-valued measures, and von Neumann measurements for the unambiguous discrimination of two mixed quantum states that occur with given prior probabilities. In particular, we…

Quantum Physics · Physics 2009-11-11 Ulrike Herzog , Janos A. Bergou

The phenomenon of quantum entanglement underlies several important protocols that enable emerging quantum technologies. Entangled states, however, are extremely delicate and often get perturbed by tiny fluctuations in their external…

Quantum Physics · Physics 2024-02-07 Jitendra Joshi , Mir Alimuddin , T S Mahesh , Manik Banik

The detection of multipartite entanglement in arbitrary dimensional systems is investigated. We derive useful $k$-separability criteria of mixed $n$-partite ($n\geq 3$) quantum states to detect $k$-nonseparable $n$-partite quantum states.…

Quantum Physics · Physics 2013-01-17 Ting Gao , Yan Hong

We investigate the problem of teleporting unknown qudit states via pure quantum channels with nonmaximal Schmidt rank. This process is mapped to the problem of discriminating among nonorthogonal symmetric states which are linearly dependent…

Quantum Physics · Physics 2012-07-11 L. Neves , M. A. Solís-Prosser , A. Delgado , O. Jiménez

In the past decades, quantum entanglement has been recognized to be the basic resource in quantum information theory. A fundamental need is then the understanding its qualification and its quantification: Is the quantum state entangled, and…

Quantum Physics · Physics 2013-02-20 Szilárd Szalay

Entanglement distillation is a key task in quantum-information processing. In this paper, we distill non-positive-partial-transpose (NPT) bipartite states of some given Schmidt rank and matrix rank. We show that all bipartite states of…

Quantum Physics · Physics 2023-07-07 Tianyi Ding , Lin Chen