Physical approximation of the partial transpose and its application to entanglement detection

Author(s):  
Hyang-Tag Lim ◽  
Yong-Su Kim ◽  
Young-Sik Ra ◽  
Joonwoo Bae ◽  
Yoon-Ho Kim
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Antoine Neven ◽  
Jose Carrasco ◽  
Vittorio Vitale ◽  
Christian Kokail ◽  
Andreas Elben ◽  
...  

AbstractWe propose an ordered set of experimentally accessible conditions for detecting entanglement in mixed states. The k-th condition involves comparing moments of the partially transposed density operator up to order k. Remarkably, the union of all moment inequalities reproduces the Peres-Horodecki criterion for detecting entanglement. Our empirical studies highlight that the first four conditions already detect mixed state entanglement reliably in a variety of quantum architectures. Exploiting symmetries can help to further improve their detection capabilities. We also show how to estimate moment inequalities based on local random measurements of single state copies (classical shadows) and derive statistically sound confidence intervals as a function of the number of performed measurements. Our analysis includes the experimentally relevant situation of drifting sources, i.e. non-identical, but independent, state copies.


2012 ◽  
Author(s):  
Hyang-Tag Lim ◽  
Yong-Su Kim ◽  
Young-Sik Ra ◽  
Joonwoo Bae ◽  
Yoon-Ho Kim

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Zheng-Hao Liu ◽  
Jie Zhou ◽  
Hui-Xian Meng ◽  
Mu Yang ◽  
Qiang Li ◽  
...  

AbstractThe Greenberger–Horne–Zeilinger (GHZ) paradox is an exquisite no-go theorem that shows the sharp contradiction between classical theory and quantum mechanics by ruling out any local realistic description of quantum theory. The investigation of GHZ-type paradoxes has been carried out in a variety of systems and led to fruitful discoveries. However, its range of applicability still remains unknown and a unified construction is yet to be discovered. In this work, we present a unified construction of GHZ-type paradoxes for graph states, and show that the existence of GHZ-type paradox is not limited to graph states. The results have important applications in quantum state verification for graph states, entanglement detection, and construction of GHZ-type steering paradox for mixed states. We perform a photonic experiment to test the GHZ-type paradoxes via measuring the success probability of their corresponding perfect Hardy-type paradoxes, and demonstrate the proposed applications. Our work deepens the comprehension of quantum paradoxes in quantum foundations, and may have applications in a broad spectrum of quantum information tasks.


2021 ◽  
Vol 127 (6) ◽  
Author(s):  
Xiao-Dong Yu ◽  
Satoya Imai ◽  
Otfried Gühne
Keyword(s):  

2015 ◽  
Vol 22 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Alexey E. Rastegin

We formulate some properties of a set of several mutually unbiased measurements. These properties are used for deriving entropic uncertainty relations. Applications of mutually unbiased measurements in entanglement detection are also revisited. First, we estimate from above the sum of the indices of coincidence for several mutually unbiased measurements. Further, we derive entropic uncertainty relations in terms of the Rényi and Tsallis entropies. Both the state-dependent and state-independent formulations are obtained. Using the two sets of local mutually unbiased measurements, a method of entanglement detection in bipartite finite-dimensional systems may be realized. A certain trade-off between a sensitivity of the scheme and its experimental complexity is discussed.


2021 ◽  
Author(s):  
Stefania Sciara ◽  
Christian Reimer ◽  
Piotr Roztocki ◽  
David J. Moss ◽  
Lucia Caspani ◽  
...  

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