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Entanglement is a key property of quantum states that acts as a resource for a wide range of tasks in quantum computing. Entanglement detection is a key conceptual and practical challenge. Without adaptive or joint measurements,…

Quantum Physics · Physics 2026-04-07 K. Bharati , Vikesh Siddhu , Krishna Jagannathan

Bipartite entangled states between a qubit and macroscopically distinct states of a mesoscopic system, known as micro-macro entangled states, are emerging resources for quantum information processing. One main challenge in generating such…

Quantum Physics · Physics 2024-10-31 Maryam Sadat Mirkamali , David G. Cory

For carrying out many quantum information protocols entanglement must be established in advance between two distant parties. Practically, inevitable interaction of entangled subsystems with their environments during distribution and storage…

Quantum Physics · Physics 2015-01-19 Xin-Wen Wang , Shi-Qing Tang , Ji-Bing Yuan , Le-Man Kuang

Quantum Fisher Information (QFI) is a ubiquitous quantity with applications ranging from quantum metrology and resource theories to condensed matter physics. In equilibrium local quantum many-body systems, the QFI of a subsystem with…

Quantum Physics · Physics 2025-04-30 Florent Ferro , Maurizio Fagotti

Multipartite entanglement, characterized by the quantum Fisher information (QFI), plays a central role in quantum-enhanced metrology and understanding quantum many-body physics. With a dynamical generalization of the Mazur-Suzuki relations,…

Quantum Physics · Physics 2023-04-04 Yu-Ran Zhang , Franco Nori

The problem of quantum state inference and the concept of quantum entanglement are studied using a non-additive measure in the form of Tsallis entropy indexed by the positive parameter q. The maximum entropy principle associated with this…

Quantum Physics · Physics 2009-10-31 Sumiyoshi Abe , A. K. Rajagopal

In its simplest form, decoherence occurs when a quantum state is entangled with a second state, but the results of measurements made on the second state are not accessible. As the second state has effectively "measured" the first, in this…

Quantum Physics · Physics 2017-05-02 Samuel P. Nolan , Simon A. Haine

We present a new approach to the analysis of entanglement in smooth bipartite continuous-variable states. One or both parties perform projective filterings via preliminary measurements to determine whether the system is located in some…

Quantum Physics · Physics 2009-11-13 H. -C. Lin , A. J. Fisher

We analyze various scenarios for entangling two initially unentangled qubits. In particular, we propose an optimal universal entangler which entangles a qubit in unknown state $|\Psi>$ with a qubit in a reference (known) state $|0>$. That…

Quantum Physics · Physics 2009-11-06 Vladimir Buzek , Mark Hillery

Entanglement are the non-local correlations permitted by quantum theory, believed to play a fundamental role in a quantum computer. We have investigated these correlations in a number of theoretical models for condensed matter systems. Such…

Quantum Physics · Physics 2007-05-23 Stein Olav Skrøvseth

Entanglement in fermion many-body systems is studied using a generalized definition of separability based on partitions of the set of observables, rather than on particle tensor products. In this way, the characterizing properties of…

Quantum Physics · Physics 2014-03-20 F. Benatti , R. Floreanini , U. Marzolino

We introduce an experimental procedure for the detection of quantum entanglement of an unknown quantum state with as few measurements as possible. The method requires neither a priori knowledge of the state nor a shared reference frame…

We investigate quantum sensing of rotation with a multi-atom Sagnac interferometer and present multi-partite entangled states to enhance the sensitivity of rotation frequency. For studying the sensitivity, we first present a Hermitian…

Quantum Physics · Physics 2019-06-05 Fei Yao , Yanming Che , Yuguo Su , Hongbin Liang , Jiancheng Pei , Xiaoguang Wang

Quantifying quantum mechanical uncertainty is vital for the increasing number of experiments that reach the uncertainty limited regime. We present a method for computing tight variance uncertainty relations, i.e., the optimal…

Quantum Physics · Physics 2017-11-01 René Schwonnek , Lars Dammeier , Reinhard F. Werner

The degree to which a pure quantum state is entangled can be characterized by the distance or angle to the nearest unentangled state. This geometric measure of entanglement is explored for bi-partite and multi-partite pure and mixed states.…

Quantum Physics · Physics 2009-05-18 Tzu-Chieh Wei

We propose and analyze a mesoscopic device producing on-demand entangled pairs of electrons. The system consists of two capacitively coupled Mach-Zehnder interferometers implemented in a quantum Hall structure. A pair of electron…

Mesoscale and Nanoscale Physics · Physics 2014-03-07 A. A. Vyshnevyy , A. V. Lebedev , G. B. Lesovik , G. Blatter

Conformal field theories in curved backgrounds have been used to describe inhomogeneous one-dimensional systems, such as quantum gases in trapping potentials and non-equilibrium spin chains. This approach provided, in a elegant and simple…

Statistical Mechanics · Physics 2019-03-26 Sara Murciano , Paola Ruggiero , Pasquale Calabrese

A common assumption in open quantum systems in general is that the noise induced by the environment, due to the continuous interaction between a quantum system and its environment, is responsible for the disappearance of quantum properties…

Quantum Physics · Physics 2022-06-07 Ali A. Abu-Nada , Moataz A. Salhab

We explore many-body entanglement in spinful Fermi gases with short-range interactions, for metrology purposes. We characterize the emerging quantum phases via Density-Matrix Renormalization Group simulations and quantify their entanglement…

Quantum Gases · Physics 2019-08-30 Leonardo Lucchesi , Maria Luisa Chiofalo

With the advance of quantum information technology, the question of how to most efficiently test quantum circuits is becoming of increasing relevance. Here we introduce the statistics of lengths of measurement sequences that allows one to…

Quantum Physics · Physics 2022-10-27 N. Milazzo , D. Braun , O. Giraud