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Generation and preservation of quantum entanglement are among the primary tasks in quantum information processing. State stabilization via quantum bath engineering offers a resource-efficient approach to achieve this objective. However,…

This paper solves the open problem of characterizing the performance of quantum illumination (QI) with discrete variable states. By devising a novel quantum measurement approach along with meticulous analysis, our investigation demonstrates…

Quantum Physics · Physics 2024-07-12 Armanpreet Pannu , Amr S. Helmy , Hesham El Gamal

This paper shows how to construct quantum entanglement states of n qubits based on a self-stabilizing token ring algorithm. The entangled states can be applied to the fields of the quantum network, quantum Internet, distributed quantum…

Quantum Physics · Physics 2022-09-26 Jehn-Ruey Jiang

Cluster states and graph states in general offer a useful model of the stabilizer formalism and a path toward the development of measurement-based quantum computation. Their defining structure - the stabilizer group - encodes all possible…

Quantum Physics · Physics 2026-01-23 Konrad Szymański , Lina Vandré , Otfried Gühne

We consider properties of states of many qubits, which arise after sending certain entangled states via various noisy channels (white noise, coloured noise, local depolarization, dephasing and amplitude damping). Entanglement of these…

Quantum Physics · Physics 2015-05-13 Wieslaw Laskowski , Tomasz Paterek , Caslav Brukner , Marek Zukowski

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…

Quantum state estimation plays a crucial role in ensuring reliable creation of entanglement within quantum networks, yet conventional Quantum State Tomography (QST) methods remain resource-intensive and impractical for scaling. To address…

We introduce and analyze an active steering protocol designed to target multipartite entangled states. The protocol involves multiple qubits subjected to weak Bell pair measurements with active feedback, where the feedback operations are…

Quantum Physics · Physics 2025-06-09 Samuel Morales , Silvia Pappalardi , Reinhold Egger

We investigate theoretically the conditions under which a multi-mode nanomechanical resonator, operated as a purely mechanical parametric oscillator, can be driven into highly nonclassical states. We find that when the device can be cooled…

Quantum Physics · Physics 2014-12-03 J. Robert Johansson , Neill Lambert , Imran Mahboob , Hiroshi Yamaguchi , Franco Nori

Entanglement allows for the nonlocality of quantum theory, which is the resource behind device-independent quantum information protocols. However, not all entangled quantum states display nonlocality, and a central question is to determine…

Quantum Physics · Physics 2016-11-09 Daniel Cavalcanti , Leonardo Guerini , Rafael Rabelo , Paul Skrzypczyk

We present two scalable and entanglement-free methods for estimating the collective state of an n-qubit quantum computer. The first method consists of a fixed set of five quantum circuits-regardless of the number of qubits-that avoid the…

Previous theoretical works showed that all pure two-qubit entangled states can generate one bit of local randomness and can be self-tested through the violation of proper Bell inequalities. We report an experiment in which nearly pure…

Quantum Physics · Physics 2019-03-14 S. Gómez , A. Mattar , I. Machuca , E. S. Gómez , D. Cavalcanti , O. Jiménez Farías , A. Acín , G. Lima

As quantum computing technology slowly matures and the number of available qubits on a QPU gradually increases, interest in assessing the capabilities of quantum computing hardware in a scalable manner is growing. One of the key properties…

Quantum Physics · Physics 2024-02-02 René Zander , Colin Kai-Uwe Becker

The study of tensor network theory is an important field and promises a wide range of experimental and quantum information theoretical applications. Matrix product state is the most well-known example of tensor network states, which…

Quantum Physics · Physics 2019-04-30 Amandeep Singh Bhatia , Mandeep Kaur Saggi

Bell inequalities have traditionally been used to demonstrate that quantum theory is nonlocal, in the sense that there exist correlations generated from composite quantum states that cannot be explained by means of local hidden variables.…

We investigate optimized quantum state preparation for quantum metrology applications in noisy environments. Using the QFI-Opt package, we simulate a low-depth variational quantum circuit (VQC) composed of a sequence of global rotations and…

Violation of the Bell-type inequalities is necessary to confirm the existence of nonlocality in nonclassical (entangled) states. We have designed a customized operator which is made of the sum of the Pauli matrices ($\sigma_x$, $\sigma_y$,…

Quantum Physics · Physics 2025-09-30 Tomis Prajapati , Harsh Mehta , Shreya Banerjee , Prasanta K. Panigrahi , V. Narayanan

Hosting non-classical states of light in three-dimensional microwave cavities has emerged as a promising paradigm for continuous-variable quantum information processing. Here we experimentally demonstrate high-fidelity generation of a range…

Error mitigation has enabled quantum computing applications with over one hundred qubits and deep circuits. The most general error mitigation methods rely on a faithful characterization of the noise channels of the hardware. However,…

Quantum state tomography serves as a key tool for identifying quantum states generated in quantum computers and simulators, typically involving local operations on individual particles or qubits to enable independent measurements. However,…

Quantum Gases · Physics 2026-03-26 Giacomo Marmorini , Takeshi Fukuhara , Daisuke Yamamoto