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We show that weakly entangled states can improve communication over a qubit channel using only separate, interference-free, measurements of individual photons. We introduce a communication task corresponding to the cryptographic primitive…

The aim of this thesis is to investigate quantum entanglement and quantum nonlocality of bipartite finite-dimensional systems (bipartite qudits). Entanglement is one of the most fascinating non-classical features of quantum theory, and…

Quantum Physics · Physics 2009-07-09 Christoph Spengler

This article delves into an analysis of the intrinsic entanglement and separability feature in quantum states as depicted by graph Laplacian. We show that the presence or absence of edges in the graph plays a pivotal role in defining the…

Quantum Physics · Physics 2024-01-05 Anoopa Joshi , Parvinder Singh , Atul Kumar

We consider quantum graph states that can be mapped to directed weighted graphs, also known as directed networks. The geometric measure of entanglement of the states is calculated for the quantum graph states corresponding to arbitrary…

Quantum Physics · Physics 2024-10-01 Kh. P. Gnatenko

This study introduces a hybrid cryptographic framework for quantum communication that integrates entanglement-assisted decryption with phase-based physical obfuscation. While conventional quantum protocols often rely on explicit…

Quantum Physics · Physics 2025-07-09 Asgar Hosseinnezhad , Hadi Sabri

We give for the first time a diagrammatic calculational tool of quantum entanglement. We present a pedagogical and simple mechanical implementation of quantum entanglement or "spooky action at a distance" to give a tangible realization of…

Mesoscale and Nanoscale Physics · Physics 2021-12-21 F. A. Buot , A. R. Elnar , G. Maglasang , C. M. Galon

We analyze tolerable quantum bit error rates in secret sharing protocols, and show that using entangled encoding states is advantageous in the case when the eavesdropping attacks are local. We also provide a criterion for security in secret…

Quantum Physics · Physics 2009-10-20 Rafal Demkowicz-Dobrzanski , Aditi Sen De , Ujjwal Sen , Maciej Lewenstein

We present a framework to study the entanglement structure of a quantum field theory inspired by the formalism of particle detectors in relativistic quantum information. This framework can in principle be used to faithfully capture…

When a quantum pure state is drawn uniformly at random from a Hilbert space, the state is typically highly entangled. This property of a random state is known as generic entanglement of quantum states and has been long investigated from…

Quantum Physics · Physics 2020-06-23 Yoshifumi Nakata , Mio Murao

We show that the geometry of the set of quantum states plays a crucial role in the behavior of entanglement in different physical systems. More specifically it is shown that singular points at the border of the set of unentangled states…

Quantum Entanglement is one of the key manifestations of quantum mechanics that separate the quantum realm from the classical one. Characterization of entanglement as a physical resource for quantum technology became of uppermost…

Quantum Physics · Physics 2025-06-03 Masoud Gharahi

While it is usually known that the mean value of a single observable is enough to detect entanglement or its distillability, the counterpart of such an approach in the case of quatum privacy has been missing. Here we develop the concept of…

Quantum Physics · Physics 2013-05-30 Konrad Banaszek , Karol Horodecki , Paweł Horodecki

We present a number of schemes that use quantum mechanics to preserve privacy, in particular, we show that entangled quantum states can be useful in maintaining privacy. We further develop our original proposal [see Phys. Lett. A 349, 75…

Quantum Physics · Physics 2015-05-30 Marianna Bonanome , Vladimir Buzek , Mark Hillery , Mario Ziman

In addition to being a workhorse for modern quantum technologies, entanglement plays a key role in fundamental tests of quantum mechanics. The entanglement of photons in multiple levels, or dimensions, explores the limits of how large an…

Quantum Physics · Physics 2018-03-12 Manuel Erhard , Mehul Malik , Anton Zeilinger

We consider the geometrization of quantum mechanics. We then focus on the pull-back of the Fubini-Study metric tensor field from the projective Hibert space to the orbits of the local unitary groups. An inner product on these tensor fields…

Mathematical Physics · Physics 2011-01-05 P. Aniello , J. Clemente-Gallardo , G. Marmo , G. F. Volkert

We investigate the entanglement properties of quantum states associated with directed graphs. Using a measure derived from the Fubini-Study metric, we quantitatively relate multipartite entanglement to the local connectivity of the graph.…

Quantum Physics · Physics 2025-09-08 Lucio De Simone , Roberto Franzosi

Quantum entanglement is one of the most important resources in quantum information. In recent years, the research of quantum entanglement mainly focused on the increase in the number of entangled qubits or the high-dimensional entanglement…

Two qubits is the simplest system where the notions of separable and entangled states and entanglement witnesses first appear. We give a three dimensional geometric description of these notions. This description however carries no…

Quantum Physics · Physics 2014-07-22 J. E. Avron , O. Kenneth

How can we use a quantum computer to detect the entanglement structure of a quantum state? Bouland et al. (2024) recently provided an algorithm that, given multiple input copies of the state, finds the "hidden cuts"-partitions into fully…

Quantum Physics · Physics 2026-03-18 Petar Simidzija , Eugene Koskin , Elton Yechao Zhu , Michael Dascal , Maria Schuld

In quantum information theory, it is a fundamental problem to construct multipartite unextendible product bases (UPBs). We show that there exist two families UPBs in Hilbert space…

Quantum Physics · Physics 2022-12-06 Yize Sun , Baoshan Wang , Shiru Li