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Related papers: Robust self testing of the 3-qubit $W$ state

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We present a method to certify the entanglement of all bipartite entangled quantum states in a device-independent way. This is achieved by placing the state in a quantum network and constructing a correlation inequality based on an…

Quantum Physics · Physics 2018-12-04 Joseph Bowles , Ivan Šupić , Daniel Cavalcanti , Antonio Acín

Device-independent (DI) certification allows the verification of quantum systems based solely on observed statistics, without assumptions about their internal structure. While self-testing, the strongest DI certification, of a wide range of…

Quantum Physics · Physics 2025-08-29 Shubhayan Sarkar

We present a framework that formulates the quest for the most efficient quantum state tomography scheme as an optimization problem which can be solved numerically. This approach can be applied to a broad spectrum of relevant setups…

Quantum Physics · Physics 2021-12-17 Violeta N. Ivanova-Rohling , Guido Burkard , Niklas Rohling

We analyze the efficacy of multiqubit W-type states as resources for quantum information. For this, we identify and generalize four-qubit W-type states. Our results show that the states can be used as resources for deterministic quantum…

Quantum Physics · Physics 2016-12-21 Parvinder Singh , Satyabrata Adhikari , Atul Kumar

We study a two-state quantum system with a non linearity intended to describe interactions with a complex environment, arising through a non local coupling term. We study the stability of particular solutions, obtained as constrained…

Analysis of PDEs · Mathematics 2023-11-30 Thierry Goudon , Simona Rota Nodari

We propose a solid-state experiment to study the process of continuous quantum measurement of a qubit state. The experiment would verify that an individual qubit stays coherent during the process of measurement (in contrast to the gradual…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Alexander N. Korotkov

Quantum measurements on a two-level system can have more than two independent outcomes, and in this case, the measurement cannot be projective. Measurements of this general type are essential to an operational approach to quantum theory,…

Reconstructing the state of a complex quantum system represents a pivotal task for all quantum information applications, both for characterization purposes and for verification of quantum protocols. Recent technological developments have…

Non-stabilizerness is an essential resource for quantum computational advantage, as stabilizer states admit efficient classical simulation. We develop a semi-device-independent framework for certifying non-stabilizer states in…

In this work, we propose a probabilistic teleportation protocol to teleport a single qubit via three-qubit W-states using two-qubit measurement basis. We show that for the proper choice of the state parameter of the resource state, it is…

Quantum Physics · Physics 2021-01-20 Satyabrata Adhikari

Self-testing usually refers to the task of taking a given set of observed correlations that are assumed to arise via a process that is accurately described by quantum theory, and trying to infer the quantum state and measurements. In other…

Quantum Physics · Physics 2024-01-17 Mirjam Weilenmann , Roger Colbeck

We consider a qubit subject to various independent control mechanisms and present a general strategy to identify both the internal Hamiltonian and the interaction Hamiltonian for each control mechanism, relying only on a single, fixed…

Quantum Physics · Physics 2009-11-10 Sonia G. Schirmer , Daniel K. L. Oi , Avinash Kolli , Jared H. Cole

Motivated by the mathematical definition of entanglement we undertake a rigorous analysis of the separability and non-distillability properties in the neighborhood of those three-qubit mixed states which are entangled and completely…

Quantum Physics · Physics 2009-11-10 Roman Orus , Rolf Tarrach

Current quantum computer technology is sufficient to realize weak measurements and the corresponding concept of weak values. We demonstrate how the weak value anomaly can be tested, along with consistency and simultaneity of weak values,…

Quantum Physics · Physics 2010-02-20 Todd A. Brun , Lajos Diosi , Walter T. Strunz

Certifying the entanglement of quantum states with Bell inequalities allows one to guarantee the security of quantum information protocols independently of imperfections in the measuring devices. Here we present a similar procedure for…

Quantum Physics · Physics 2014-09-19 Adam Bennet , Tamás Vértesi , Dylan J. Saunders , Nicolas Brunner , G. J. Pryde

The intrinsic non-locality of correlations in Quantum Mechanics allow us to certify the behaviour of a quantum mechanism in a device independent way. In particular, we present a new protocol that allows an unbounded amount of randomness to…

Quantum Physics · Physics 2018-08-01 Brian Coyle , Matty J. Hoban , Elham Kashefi

Vast developments in quantum technology have enabled the preparation of quantum states with more than a dozen entangled qubits. The full characterization of such systems demands distinct constructions depending on their specific type and…

The notion of a qubit is ubiquitous in quantum information processing. In spite of the simple abstract definition of qubits as two-state quantum systems, identifying qubits in physical systems is often unexpectedly difficult. There are an…

Quantum Physics · Physics 2009-11-07 Lorenza Viola , Emanuel Knill , Raymond Laflamme

Tomographic reconstruction of the many-body quantum state of a scalable qubit system is of paramount importance in quantum computing technologies. However, conventional approaches which use tomographically orthogonal base measurements…

Quantum Physics · Physics 2024-10-31 Kangheun Kim , Jaewook Ahn

Quantum tomography is the main method used to assess the quality of quantum information processing devices, but its complexity presents a major obstacle for the characterization of even moderately large systems. The number of experimental…

Quantum Physics · Physics 2015-03-19 Marcus P. da Silva , Olivier Landon-Cardinal , David Poulin