English
Related papers

Related papers: Lower Bounds for Attainable Fidelity in Entangleme…

200 papers

We have studied the entanglement of purification $E_p$ in a non-conformal holographic model which is a 5- dimensional Einstein gravity coupled to a scalar field $\phi$ with a non-trivial potential $V(\phi)$. The dual 4-dimensional gauge…

High Energy Physics - Theory · Physics 2024-08-13 M. Asadi

We present an entanglement purification protocol for a mixture of a pure entangled state and a pure product state, which are orthogonal to each other. The protocol is combination of bisection method and one-way hashing protocol. We give…

Quantum Physics · Physics 2009-08-06 Mikolaj Czechlewski , Andrzej Grudka , Satoshi Ishizaka , Antoni Wojcik

Uniform continuity bounds on entropies are generally expressed in terms of a single distance measure between a pair of probability distributions or quantum states, typically, the total variation distance or trace distance. However, if an…

Quantum Physics · Physics 2025-01-09 Michael G. Jabbour , Nilanjana Datta

Quantum networks rely on high fidelity entangled pairs distributed to nodes, but maintaining their fidelity is challenged by environmental decoherence during storage. Entanglement purification is used to restore fidelity, but the idle…

Networking and Internet Architecture · Computer Science 2025-09-05 Vivek Vasan , Alexander Nico-Katz , Boulat A. Bash , Daniel C. Kilper , Marco Ruffini

Experimentally quantifying entanglement and coherence are extremely important for quantum resource theory. However, because the quantum state tomography requires exponentially growing measurements with the number of qubits, it is hard to…

Quantum Physics · Physics 2020-05-13 Yue Dai , Yuli Dong , Zhenyu Xu , Wenlong You , Chengjie Zhang , Otfried Gühne

In [J. C. Howell and J. A. Yeazell, Phys. Rev. A 62, 012102 (2000)], a proposal is made to generate entangled macroscopically distinguishable states of two spatially separated traveling optical modes. We model the decoherence due to light…

Quantum Physics · Physics 2016-04-26 J. Clausen , L. Knoell , D. -G. Welsch

Entanglement detection is one of the most fundamental tasks in quantum information science, playing vital roles in theoretical studies and quantum system benchmarking. Researchers have proposed many powerful entanglement criteria with high…

Quantum Physics · Physics 2024-03-05 Zhenhuan Liu , Fuchuan Wei

A method for producing an upper bound for all multipartite purification protocols is devised, based on knowing the optimal protocol for purifying bipartite states. When applied to a range of noise models, both local and correlated, the…

Quantum Physics · Physics 2007-06-13 Alastair Kay , Jiannis K. Pachos

Quantum data-center networks must distribute entanglement between QPUs over paths whose length grows with system scale, but each entanglement-swapping step reduces the quality of the raw end-to-end state. Topology, multiplexing, and…

Recently Xiao et al. proposed a scheme for entanglement purification based on doubly entangled photon states (Phys. Rev. A 77(2008) 042315). We modify their scheme for improving the efficiency of entanglement purification. This modified…

Quantum Physics · Physics 2008-10-14 Chuan Wang , Yu-Bo Sheng , Xi-Han Li , Fu-Guo Deng , Wei Zhang , Gui Lu Long

Long-distance quantum communication requires reliable entanglement distribution, but direct generation with protocols such as Barrett--Kok suffers from exponentially decreasing success probability with distance, making it impractical over…

Quantum Physics · Physics 2025-10-10 Wenhan Li , Shiyu Zhang

Coherence and entanglement are fundamental properties of quantum systems, promising to power the near future quantum computers, sensors and simulators. Yet, their experimental detection is challenging, usually requiring full reconstruction…

Quantum Physics · Physics 2017-08-01 Graeme Smith , John A. Smolin , Xiao Yuan , Qi Zhao , Davide Girolami , Xiongfeng Ma

Quantum entanglement plays crucial roles in quantum information processing. Quantum entangled states have become the key ingredient in the rapidly expanding field of quantum information science. Although the nonclassical nature of…

Quantum Physics · Physics 2010-12-22 Ming Li , Shao-Ming Fei , Xianqing Li-Jost

We propose a scheme to measure the parity of two distant qubits, while ensuring that losses on the quantum channel between them does not destroy coherences within the parity subspaces. This capability enables deterministic preparation of…

Quantum Physics · Physics 2017-04-05 Alain Sarlette , Mazyar Mirrahimi

Measures of entanglement can be employed for the analysis of numerous quantum information protocols. Due to computational convenience, logarithmic negativity is often the choice in the case of continuous variable systems. In this work, we…

Measures of entanglement, fidelity and purity are basic yardsticks in quantum information processing. We propose how to implement these measures using linear devices and homodyne detectors for continuous variable Gaussian states. In…

Quantum Physics · Physics 2009-11-07 M. S. Kim , Jinhyoung Lee , W. J. Munro

Randomized matrix sparsification has proven to be a fruitful technique for producing faster algorithms in applications ranging from graph partitioning to semidefinite programming. In the decade or so of research into this technique, the…

Numerical Analysis · Mathematics 2009-11-23 Alex Gittens , Joel A. Tropp

We study how entanglement among the register qubits affects the gate fidelity in the one-way quantum computation if a measurement is inaccurate. We derive an inequality which shows that the mean gate fidelity is upper bounded by a…

Quantum Physics · Physics 2015-05-18 Tomoyuki Morimae

As the hyperentanglement of photon systems presents lots of unique opportunities in high-capacity quantum networking, the hyperentanglement purification protocol (hyper-EPP) becomes a vital project work and the quality of its accomplishment…

Quantum Physics · Physics 2018-12-05 Guan-Yu Wang , Tao Li , Qing Ai , Ahmed Alsaedi , Tasawar Hayat , Fu-Guo Deng

Fidelity is a fundamental measure for the closeness of two quantum states, which is important both from a theoretical and a practical point of view. Yet, in general, it is difficult to give good estimates of fidelity, especially when one…

Quantum Physics · Physics 2022-03-31 András Gilyén , Alexander Poremba