Article
Optics
Florian Pimpel, Martin J. Renner, Armin Tavakoli
Summary: We investigate whether pure entangled states can be associated with a measurement basis. We prove that for bipartite states with a local dimension of 2, 4, or 8, every state corresponds to a basis. Numerical calculations strongly suggest the same conclusion for two qutrits and three qubits. However, for some states of four qubits, we are unable to find a basis, leading us to conjecture that not all quantum states have a corresponding measurement basis.
Article
Optics
David Gunn, Martin Hebenstreit, Cornelia Spee, Julio I. de Vicente, Barbara Kraus
Summary: Understanding multipartite entanglement is a crucial goal in quantum information. In the case of multipartite pure states, it has been shown that they are generically isolated and cannot be transformed under local operations assisted by classical communication (LOCC). However, in a real laboratory, transformations are often approximate rather than exact. This motivates the study of approximate LOCC transformations. In this article, the authors review the known results for bipartite states and present the remaining gaps in the multipartite case. They show that it is sufficient to consider pure initial states, LOCC protocols with finitely many rounds of communication, and approximate transformations can be approximated by ensemble transformations within an SLOCC class.
Article
Physics, Multidisciplinary
Tulja Varun Kondra, Chandan Datta, Alexander Streltsov
Summary: This study explores the quantification of quantum entanglement and its relationship with entanglement distillation. It is shown that entanglement entropy completely characterizes state transformations in the presence of entangled catalysts, giving operational significance to asymptotic results in the single-copy setting.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Tommaso Comparin, Fabio Mezzacapo, Tommaso Roscilde
Summary: This paper investigates the scalable production of multipartite entangled states in ensembles of qubits with dipolar interactions governed by U(1) symmetric Hamiltonians. The authors theoretically show that the nonequilibrium dynamics generated by this Hamiltonian shares fundamental features with the one-axis-twisting model. They observe that as the number of qubits increases, the entanglement features of these states also exhibit scalability, which is crucial for metrology.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Lorenzo Piroli, Georgios Styliaris, J. Ignacio Cirac
Summary: This paper introduces deterministic state transformation protocols between many-body quantum states using low-depth quantum circuits, local operations, and classical communication. It shows a classification of phases where topologically ordered states or other entangled states become trivial. It also explores how the set of unitary operations is enhanced by local operations and classical communication, allowing certain large-depth quantum circuits to be performed in terms of low-depth ones.
PHYSICAL REVIEW LETTERS
(2021)
Article
Quantum Science & Technology
Zhi-Chao Zhang, Guo-Jing Tian, Tian-Qing Cao
Summary: The study introduces the concept of strong nonlocality of orthogonal entangled states, discussing the local indistinguishability and local reducibility of quantum states under certain conditions, showing that these states exhibit strong nonlocality.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Physics, Multidisciplinary
Antoine Neven, David Kenworthy Gunn, Martin Hebenstreit, Barbara Kraus
Summary: The study introduces an extension of LOCC known as multi-state LOCC, which allows for quantitative analysis of multipartite entanglement and enables state conversions and entanglement transfer not possible in single copy scenarios. The research demonstrates that multi-state LOCC has a much richer landscape and more diverse applications compared to single-state LOCC.
Article
Quantum Science & Technology
Samuel R. Hedemann
Summary: We provide a comprehensive definition of mixed maximally entangled (MME) states for multipartite systems, and derive a set of necessary and sufficient conditions for their existence. We give specific examples and present a large collection of tabulated multipartite MME states in various systems. MME states are a special type of mixed state where every decomposition is maximally entangled. Multipartite MME states likely have important applications and serve as critical performance goals for entanglement measures.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Multidisciplinary Sciences
Jia-Bin Zhang, Tao Li, Qing-Hua Zhang, Shao-Ming Fei, Zhi-Xi Wang
Summary: The detection of multipartite entanglement is studied based on generalized local uncertainty relations. A sufficient criterion for the entanglement of four-partite quantum systems is presented, with detailed examples illustrating its advantages. The approach is generalized to general multipartite entanglement cases.
SCIENTIFIC REPORTS
(2021)
Article
Optics
Gaoyan Zhu, Chengjie Zhang, Kunkun Wang, Lei Xiao, Peng Xue
Summary: We experimentally demonstrate a method for detecting entanglement using a limited set of local measurements. The method does not require prior knowledge about the form of entanglement witnesses and has been successfully applied to both pure and mixed two-qubit entangled states. The results show the validity of the method and provide a practical test bed for entanglement witness experiments.
PHOTONICS RESEARCH
(2022)
Article
Physics, Multidisciplinary
Kwang-Il Kim, Myong Chol Pak, Tae-Hyok Kim, Jong Chol Kim, Yong-Hae Ko, Hak Chol Pak
Summary: The robustness of GHZ states, evaluated by tau and GM concurrence as measures of genuine tripartite entanglement, is found to be equal. Similarly, the robustness of Bell states is equal under different noisy channels.
Article
Materials Science, Multidisciplinary
Luping Zhang, Fang Jia, Huan Zhang, Wei Ye, Ying Xia, Liyun Hu, Jiehui Huang
Summary: This study proposes a scheme for improving entanglement using number-conserving generalized superposition of products (GSP) operation. It is found that both single-mode and two-mode-symmetric GSP operations can effectively enhance entanglement. Compared to other non-Gaussian operations, this scheme shows better entanglement performance at a small amplitude level. In addition, when used for teleportation, this scheme achieves the optimal teleportation fidelity.
RESULTS IN PHYSICS
(2022)
Article
Physics, Multidisciplinary
C. Munoz, M. Gaeta, A. B. Klimov
Summary: For the N-qubit cluster state, all macroscopic properties remain asymptotically invariant under local transformations when N is significantly larger than 1, and can be characterized by a distribution function similar to that of a completely mixed state.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Quantum Science & Technology
Oskar Slowik, Adam Sawicki, Tomasz Maciazek
Summary: This paper discusses the design of critical states with arbitrarily large local unitary symmetry and their potential realization in quantum systems with distinguishable traps. The study also links the results with the existence of strictly semistable states with specific asymptotic diagonal symmetries.
Article
Physics, Multidisciplinary
LiMei Zhang, Ting Gao, FengLi Yan
Summary: This study focuses on the transformations of multilevel coherent resource states, showing that any two such states can be interconverted with a nonzero probability through specific coherent-preserving maps. Additionally, it is discovered that no resource state is isolated in the framework of multilevel coherence, with the possibility of interconversion between different coherent states.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2021)
Article
Optics
Michael Skotiniotis, Florian Froewis, Wolfgang Duer, Barbara Kraus
Article
Optics
D. Sauerwein, K. Schwaiger, M. Cuquet, J. I. de Vicente, B. Kraus
Article
Physics, Multidisciplinary
K. Schwaiger, D. Sauerwein, M. Cuquet, J. I. de Vicente, B. Kraus
PHYSICAL REVIEW LETTERS
(2015)
Article
Physics, Mathematical
C. Spee, J. I. de Vicente, B. Kraus
JOURNAL OF MATHEMATICAL PHYSICS
(2016)
Article
Physics, Mathematical
Gilad Gour, Barbara Kraus, Nolan R. Wallach
JOURNAL OF MATHEMATICAL PHYSICS
(2017)
Article
Physics, Multidisciplinary
C. Spee, J. I. de Vicente, D. Sauerwein, B. Kraus
PHYSICAL REVIEW LETTERS
(2017)
Article
Physics, Multidisciplinary
Martin Hebenstreit, Barbara Kraus, Laurin Ostermann, Helmut Ritsch
PHYSICAL REVIEW LETTERS
(2017)
Article
Optics
C. Spee, K. Schwaiger, G. Giedke, B. Kraus
Article
Optics
M. Hebenstreit, D. Alsina, J. I. Latorre, B. Kraus
Article
Optics
J. I. de Vicente, C. Spee, D. Sauerwein, B. Kraus
Article
Optics
David Sauerwein, Chiara Macchiavello, Lorenzo Maccone, Barbara Kraus
Article
Optics
W. L. Boyajian, M. Skotiniotis, W. Duer, B. Kraus
Article
Optics
M. Hebenstreit, C. Spee, B. Kraus
Article
Optics
Hayata Yamasaki, Alexander Pirker, Mio Murao, Wolfgang Duer, Barbara Kraus