scholarly journals Experimental Demonstration of Fine-Grained Steering Inequality of Two-Qubit Mixed States

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 514
Author(s):  
Zhi-Hao Bian ◽  
Cong-Yue Yin
Keyword(s):  
Quantum Correlation ◽  
Uncertainty Relation ◽  
Detection Efficiency ◽  
Detector Efficiency ◽  
Experimental Demonstration ◽  
Mixed States ◽  
Fine Grained ◽  
Quantum Steering ◽  
Werner States ◽  
Precision And Accuracy

Quantum steering, as a cornerstone of quantum information, is usually used to witness the quantum correlation of bipartite and multi-partite states. Here, we experimentally demonstrate the quantum steering inequality of two-qubit mixed states based on the fine-grained uncertainty relation. Our experimental results show that the steering inequality has potent sensitivity to Werner states and Bell diagonal states. The steering strategy exhibits a strong ability to identify that Werner states are steerable when the decoherence coefficient a>12. Compared to the steering inequality obtained by another stratagem, the steering witness criteria of mixed states based on the fine-grained uncertainty relation demonstrated in our experiment has better precision and accuracy. Moreover, the detection efficiency in our measurement setup is only required to be 50% to close the detection loophole, which means our approach needs less detector efficiency to certificate the steerability of mixed states.

scholarly journals Entropic Steering Criteria: Applications to Bipartite and Tripartite Systems

Entropy ◽  
2018 ◽  
Vol 20 (10) ◽  
pp. 763 ◽  
Author(s):  
Ana Costa ◽  
Roope Uola ◽  
Otfried Gühne
Keyword(s):  
Relative Entropy ◽  
Uncertainty Relation ◽  
Uncertainty Relations ◽  
W States ◽  
Entropic Uncertainty Relations ◽  
Entropic Uncertainty Relation ◽  
Local Measurements ◽  
Action At A Distance ◽  
Quantum Steering ◽  
Joint Convexity

The effect of quantum steering describes a possible action at a distance via local measurements. Whereas many attempts on characterizing steerability have been pursued, answering the question as to whether a given state is steerable or not remains a difficult task. Here, we investigate the applicability of a recently proposed method for building steering criteria from generalized entropic uncertainty relations. This method works for any entropy which satisfy the properties of (i) (pseudo-) additivity for independent distributions; (ii) state independent entropic uncertainty relation (EUR); and (iii) joint convexity of a corresponding relative entropy. Our study extends the former analysis to Tsallis and Rényi entropies on bipartite and tripartite systems. As examples, we investigate the steerability of the three-qubit GHZ and W states.

Quantum correlation swapping in parallel and antiparallel two-qubit mixed states

2019 ◽  
Vol 18 (4) ◽  
Author(s):  
Chuanmei Xie ◽  
Yimin Liu ◽  
Jianlan Chen ◽  
Zhanjun Zhang
Keyword(s):  
Quantum Correlation ◽  
Mixed States

scholarly journals Experimental test of fine-grained entropic uncertainty relation in the presence of quantum memory

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Wei-Min Lv ◽  
Chao Zhang ◽  
Xiao-Min Hu ◽  
Yun-Feng Huang ◽  
Huan Cao ◽  
...  
Keyword(s):  
Experimental Test ◽  
Uncertainty Relation ◽  
Quantum Memory ◽  
Fine Grained ◽  
Entropic Uncertainty Relation

Uncertainty Relation: From Inequality to Equality

1997 ◽  
Vol 52 (1-2) ◽  
pp. 49-52 ◽  
Author(s):  
Georg Süssmann
Keyword(s):  
Phase Space ◽  
Quantum State ◽  
Uncertainty Relation ◽  
The Other ◽  
Mixed States ◽  
Von Neumann ◽  
Other Hand ◽  
Pure Quantum State ◽  
Minimum Uncertainty

Abstract The uncertainty area δ (p, q): - [∫ W(p, q)2 dp dq] - 1 is proposed in place of δ p • δ q, and it is shown that each pure quantum state is a minimum uncertainty state in this sense: δ (p, q) = 2 π ħ. For mixed states, on the other hand, δ(p, q) > 2π ħ. In a phase space of 2F(=6N) dimensions, S: = k B • log[δF (p,q)/(2 π ħ)F] whit δF (p,q):= [∫ W(p, q)2 dF p dF q]-1 is considered as an alternative to von Neumann`s entropy S̃:= kB • trc [ρ̂ log (ρ̂-1)].

scholarly journals Increasing Quantum Correlations Based on Measurement-Induced Disturbance via a Swapping Procedure with Two-Qubit Mixed States

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1606
Author(s):  
Chuanmei Xie ◽  
Feiyang Wu ◽  
Zhanjun Zhang ◽  
Jiawei Liang ◽  
Xiaofeng Yin
Keyword(s):  
Quantum Correlation ◽  
Quantum Correlations ◽  
Mixed States

In this paper, quantum correlation (QC) swapping for certain separable two-qubit mixed states is treated. A QC quantifier, measurement-induced disturbance (MID) (Luo in Phys Rev A 77:022301, 2008), is employed to characterize and quantify QCs in the relevant states. Properties of all QCs in the swapping process are revealed. Particularly, it is found that MID can be increased through QC swapping for certain separable two-qubit mixed states.

scholarly journals Erratum: Experimental demonstration of a universally valid error–disturbance uncertainty relation in spin measurements

2012 ◽  
Vol 8 (8) ◽  
pp. 634-634 ◽  
Author(s):  
Jacqueline Erhart ◽  
Stephan Sponar ◽  
Georg Sulyok ◽  
Gerald Badurek ◽  
Masanao Ozawa ◽  
...  
Keyword(s):  
Uncertainty Relation ◽  
Experimental Demonstration ◽  
Spin Measurements

Quantum-memory-assisted entropic uncertainty in fluctuating electromagnetic field with a boundary

2019 ◽  
Vol 34 (17) ◽  
pp. 1950099
Author(s):  
Zhiming Huang ◽  
Xiaobin Wang ◽  
Yiyong Ye ◽  
Xiaokui Sheng ◽  
Zhenbang Rong ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Master Equation ◽  
Quantum Correlation ◽  
Uncertainty Relation ◽  
Boundary Effect ◽  
Quantum Memory ◽  
Plane Boundary ◽  
Evolution Time ◽  
Entropic Uncertainty Relation ◽  
Level Atom

In this work, we investigate the dynamics of quantum-memory-assisted entropic uncertainty relation for a two-level atom coupled with fluctuating electromagnetic field in the presence of a perfectly reflecting plane boundary. The solution of the master equation that governs the system evolution is derived. We find that entropic uncertainty and mixedness increase to a stable value with evolution time, but quantum correlation reduces to zero with evolution time. That is, the mixedness is positively associated with entropic uncertainty, however, increasing quantum correlation can cause the decrease of the uncertainty. The tightness of entropic uncertainty grows at first and then declines to zero with evolution time. In addition, entropic uncertainty fluctuates to relatively stable values with increasing the atom’s distance from the boundary, especially for short evolution time, which suggests a possible way of testing the vacuum fluctuating and boundary effect. Finally, we propose an effective method to control the uncertainty via quantum weak measurement reversal.

Fine-grained uncertainty relation for open quantum system

2021 ◽  
Author(s):  
Shang-Bin Han ◽  
Shuai-Jie Li ◽  
Jing-Jun Zhang ◽  
Jun Feng
Keyword(s):  
Quantum System ◽  
Uncertainty Relation ◽  
Open Quantum System ◽  
Open Quantum ◽  
Fine Grained

Quantum correlation based on weak measurements

2017 ◽  
Vol 15 (06) ◽  
pp. 1750041 ◽  
Author(s):  
Yangyang Wang ◽  
Jinchuan Hou ◽  
Xiaofei Qi
Keyword(s):  
Pure State ◽  
Quantum Correlation ◽  
Qubit State ◽  
Sufficient Condition ◽  
Product State ◽  
Necessary And Sufficient Condition ◽  
Weak Measurements ◽  
Werner States ◽  
Necessary And Sufficient ◽  
Isotropic States

A quantum correlation [Formula: see text] based on weak measurements for bipartite systems is introduced. It is shown that the product states do not contain this quantum correlation. Also, the necessary and sufficient condition for any two-qubit state becoming a product state is obtained. The quantum correlation [Formula: see text] and other quantum correlation for two-qubit entangled pure state, Werner states and isotropic states are compared.

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