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Related papers: Certifying entanglement dimensionality by random P…

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We consider the task of quantum state certification: given a description of a hypothesis state $\sigma$ and multiple copies of an unknown state $\rho$, a tester aims to determine whether the two states are equal or $\epsilon$-far in trace…

Quantum Physics · Physics 2025-07-09 Ryan O'Donnell , Chirag Wadhwa

Entanglement plays a central role in quantum information processing, indicating the non-local correlation of quantum matters. However, few effective ways are known to detect the amount of entanglement of an unknown quantum state. In this…

Quantum Physics · Physics 2020-11-26 You Zhou , Pei Zeng , Zhenhuan Liu

We undertake experimental detection of the entanglement present in arbitrary three-qubit pure quantum states on an NMR quantum information processor. Measurements of only four observables suffice to experimentally differentiate between the…

Quantum Physics · Physics 2018-09-06 Amandeep Singh , Harpreet Singh , Kavita Dorai , Arvind

Entanglement plays a crucial role in quantum information science and many-body physics, yet quantifying it in mixed quantum many-body systems has remained a notoriously difficult problem. Here, we introduce families of quantitative…

Quantum Physics · Physics 2025-07-21 Poetri Sonya Tarabunga , Tobias Haug

Reliable randomness is a core ingredient in algorithms and applications ranging from numerical simulations to statistical sampling and cryptography. The outcomes of measurements on entangled quantum states can violate Bell inequalities,…

Entanglement is one of the physical properties of quantum systems responsible for the computational hardness of simulating quantum systems. But while the runtime of specific algorithms, notably tensor network algorithms, explicitly depends…

Quantum state tomography is a fundamental problem in quantum computing. Given $n$ copies of an unknown $N$-qubit state $\rho \in \mathbb{C}^{d \times d},d=2^N$, the goal is to learn the state up to an accuracy $\epsilon$ in trace distance,…

Quantum Physics · Physics 2025-02-26 Jayadev Acharya , Abhilash Dharmavarapu , Yuhan Liu , Nengkun Yu

Quantum entanglement is an essential resource for quantum science and technology. However, entanglement detection and quantification, via typical entanglement measures such as linear entanglement entropy or negativity, can be a very…

Quantum Physics · Physics 2025-06-17 Diego Fallas Padilla , Mingjian Zhu , Han Pu

The characterization of high-dimensional quantum entanglement is crucial for advanced quantum computing and quantum information algorithms. Traditional methods require extensive data acquisition and suffer from limited visibility due to…

Quantum Physics · Physics 2025-11-18 Stav Lotan , Hugo Defienne , Ronen Talmon , Guy Bartal

We consider entanglement purification protocols for multiple copies of qubit states. We use high-dimensional auxiliary entangled systems to learn about number and positions of errors in the noisy ensemble in an explicit and controlled way,…

Quantum Physics · Physics 2021-07-28 Ferran Riera Sàbat , Pavel Sekatski , Alexander Pirker , Wolfgang Dür

Entanglement purification is to distill high-quality entangled states from low-quality entangled states. It is a key step in quantum repeaters, determines the efficiency and communication rates of quantum communication protocols, and is…

Quantum Physics · Physics 2022-03-21 Cen-Xiao Huang , Xiao-Min Hu1 , Bi-Heng Liu , Lan Zhou , Yu-Bo Sheng , Chuan-Feng Li , Guang-Can Guo

High-dimensional entanglement provides unique ways of transcending the limitations of current approaches in quantum information processing, quantum communications based on qubits. The generation of time-frequency qudit states offer…

We introduce a hierarchical algorithm for identifying the largest Pauli coefficients of an unknown $n$-qubit quantum state. The algorithm traverses a prefix-based tree whose nodes represent partial sums of squared Pauli coefficients, always…

Experimental procedures are presented for the rapid detection of entanglement of unknown arbitrary quantum states. The methods are based on the entanglement criterion using accessible correlations and the principle of correlation…

We propose a new protocol of \textit{universal} entanglement concentration, which converts many copies of an \textit{unknown} pure state to an \textit{% exact} maximally entangled state. The yield of the protocol, which is outputted as a…

Quantum Physics · Physics 2013-05-29 Keiji Matsumoto , Masahito Hayashi

The initialization of a quantum system into a certain state is a crucial aspect of quantum information science. While a variety of measurement strategies have been developed to characterize how well the system is initialized, for a given…

We examine the problem of finding the minimum number of Pauli measurements needed to uniquely determine an arbitrary $n$-qubit pure state among all quantum states. We show that only $11$ Pauli measurements are needed to determine an…

The resources needed to conventionally characterize a quantum system are overwhelmingly large for high- dimensional systems. This obstacle may be overcome by abandoning traditional cornerstones of quantum measurement, such as general…

Quantum Physics · Physics 2016-05-17 Gregory A. Howland , Samuel H. Knarr , James Schneeloch , Daniel J. Lum , John C. Howell

Let a pure state \psi be chosen randomly in an NM-dimensional Hilbert space, and consider the reduced density matrix \rho of an N-dimensional subsystem. The bipartite entanglement properties of \psi are encoded in the spectrum of \rho. By…

Mathematical Physics · Physics 2013-05-16 Fabio Deelan Cunden , Paolo Facchi , Giuseppe Florio , Saverio Pascazio

Characterizing entanglement of systems composed of multiple particles is a very complex problem that is attracting increasing attention across different disciplines related to quantum physics. The task becomes even more complex when the…

Quantum Physics · Physics 2026-02-12 Shuheng Liu , Qiongyi He , Marcus Huber , Giuseppe Vitagliano
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