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Bound entanglement, a weak -- yet resourceful -- form of quantum entanglement, remains notoriously hard to detect and construct. We address this in this paper by leveraging symmetric random induced states, where positive partial transpose…

Quantum Physics · Physics 2026-05-20 Jonathan Louvet , François Damanet , Thierry Bastin

We propose a method to generate large cluster states without using conditional (e.g., CNOT, C-phase) gates. Indeed, an arbitrarily large cluster state can be generated and expanded almost deterministically by single-qubit rotations and a…

Quantum Physics · Physics 2009-11-13 Xiang-bin Wang , J. Q. You , Franco Nori

An optimal local conversion strategy between any two pure states of a bipartite system is presented. It is optimal in that the probability of success is the largest achievable if the parties which share the system, and which can communicate…

Quantum Physics · Physics 2009-10-31 Guifre Vidal

An important problem in quantum information theory is to understand what makes entangled quantum systems non-local or hard to simulate efficiently. In this work we consider situations in which various parties have access to a restricted set…

Quantum Physics · Physics 2014-12-19 Hussain Anwar , Sania Jevtic , Oliver Rudolph , Shashank Virmani

We present two method for optimal entanglement concentration from pure entangled states by local actions only. However a prior knowledge of the Schmidt coefficients is required. The first method is optimally efficient only when a finite…

Quantum Physics · Physics 2009-10-31 Somshubhro Bandyopadhyay

Measurement-based quantum computation (MBQC) represents a powerful and flexible framework for quantum information processing, based on the notion of entangled quantum states as computational resources. The most prominent application is the…

Quantum Physics · Physics 2014-05-26 B. P. Lanyon , P. Jurcevic , M. Zwerger , C. Hempel , E. A. Martinez , W. Dür , H. J. Briegel , R. Blatt , C. F. Roos

Using a spontaneous parametric-downconversion source of photon pairs, we are working towards the creation of arbitrary 2-qubit quantum states with high fidelity. Currently, all physically allowable combinations of polarization entanglement…

Quantum Physics · Physics 2007-05-23 Paul Kwiat , Joe Altepeter , David Branning , Evan Jeffrey , Nicholas Peters , Tzu-Chieh Wei

We have found a quantum cloning machine that optimally duplicates the entanglement of a pair of $d$-dimensional quantum systems. It maximizes the entanglement of formation contained in the two copies of any maximally-entangled input state,…

Quantum Physics · Physics 2007-05-23 E. Karpov , P. Navez , N. J. Cerf

Entanglement between the constituents of a quantum system is an essential resource in the implementation of many quantum processes and algorithms. Indeed, universal quantum computation is possible by measuring individual qubits comprising…

Quantum Physics · Physics 2012-02-10 David L. Feder

Maximally entangled mixed states are those states that, for a given mixedness, achieve the greatest possible entanglement. For two-qubit systems and for various combinations of entanglement and mixedness measures, the form of the…

Generating entangled states is one of the most important tasks in quantum information technology. However, in reality any entanglement generator must contain some characteristic uncertainty, and as a result the produced entangled state…

Quantum Physics · Physics 2019-02-20 Kensuke Gallock Yoshimura , Naoki Yamamoto

Many experiments in quantum information aim at creating multi-partite entangled states. Quantifying the amount of entanglement that was actually generated can, in principle, be accomplished using full-state tomography. This method requires…

Quantum Physics · Physics 2015-05-13 Harald Wunderlich , Martin B. Plenio

The determination of the state fidelity and the detection of entanglement are fundamental problems in quantum information experiments. We investigate how these goals can be achieved with a minimal effort. We show that the fidelity of GHZ…

Quantum Physics · Physics 2008-09-27 Otfried Gühne , Chao-Yang Lu , Wei-Bo Gao , Jian-Wei Pan

Clustering, or grouping, dataset elements based on similarity can be used not only to classify a dataset into a few categories, but also to approximate it by a relatively large number of representative elements. In the latter scenario,…

Machine Learning · Computer Science 2019-09-13 Tim Jaschek , Marko Bucyk , Jaspreet S. Oberoi

In recent years, the entanglement spectra of quantum states have been identified to be highly valuable for improving our understanding on many problems in quantum physics, such as classification of topological phases, symmetry-breaking…

Quantum Physics · Physics 2019-06-04 Bin Cheng , Man-Hong Yung

Entanglement is one of the key resources required for quantum computation, so experimentally creating and measuring entangled states is of crucial importance in the various physical implementations of a quantum computer. In superconducting…

Assessing the quality of an ensemble of noisy entangled states is a central task in quantum information processing. Usually this is done by measuring and hence destroying multiple copies, from which state tomography or fidelity estimation…

Quantum Physics · Physics 2023-02-14 Ferran Riera-Sàbat , Jorge Miguel-Ramiro , Wolfgang Dür

The states in the three-qubit GHZ SLOCC class can exhibit diverse entanglement patterns, as they may have no entanglement in any reduced subsystems, or show entanglement across one, two, or all three bipartite cuts. Significant research has…

We present an approach to characterize genuine multiparticle entanglement using appropriate approximations in the space of quantum states. This leads to a criterion for entanglement which can easily be calculated using semidefinite…

Quantum Physics · Physics 2011-05-13 Bastian Jungnitsch , Tobias Moroder , Otfried Gühne

Entanglement is a powerful concept with an enormous potential for scientific and technological advances. A central focus in modern research is to extend the generation and control of entangled states from few to many qubits, and protect…

Quantum Physics · Physics 2024-06-04 Philip Thomas , Leonardo Ruscio , Olivier Morin , Gerhard Rempe