scholarly journals Monogamy relations of all quantum correlation measures for multipartite quantum systems

2019 ◽  
Vol 446 ◽  
pp. 39-43 ◽  
Author(s):  
Zhi-Xiang Jin ◽  
Shao-Ming Fei
Keyword(s):  
Quantum Correlation ◽  
Quantum Systems ◽  
Multipartite Quantum Systems ◽  
Correlation Measures ◽  
Monogamy Relations

scholarly journals Selective Phase Rotation Quantum Gate Entangler

2009 ◽  
Vol 16 (04) ◽  
pp. 407-412
Author(s):  
Hoshang Heydari
Keyword(s):  
Integral Transform ◽  
Quantum Algorithms ◽  
Quantum Systems ◽  
Quantum Gate ◽  
Multipartite Quantum Systems ◽  
Phase Rotation ◽  
Quantum Integral ◽  
Qubit States

We construct a quantum gate entangler for multi-qubit states based on a selective phase rotation transform. In particular, we establish a relation between the quantum integral transform and the quantum gate entangler in terms of universal controlled gates for multi-qubit states. Our result gives an effective way of constructing topological and geometrical quantum gate entanglers for multipartite quantum systems, which could also lead to a construction of geometrical quantum algorithms.

Decoherence in two-dimensional quantum walks with two- and four-state coins

2021 ◽  
Author(s):  
Yu-Guang Yang ◽  
Xi-Xi Wang ◽  
Jian Li ◽  
Dan Li ◽  
Yi-Hua Zhou ◽  
...  
Keyword(s):  
Quantum Correlation ◽  
Quantum Systems ◽  
Quantum Walks ◽  
Two Dimensional ◽  
Link Type ◽  
Experimental Implementation ◽  
Spatial Dimensions

Two-dimensional quantum walks using a two-state coin have simpler experimental implementation than two-dimensional quantum walks using a four-state coin. However, decoherence occurs inevitably during the evolution of quantum walks due to the coupling between the quantum systems and their environment. Thus, it is interesting to investigate the robustness against decoherence for two- and four-state two-dimensional quantum walks. Here, we investigate the effects of the decoherence on two- and four-state two-dimensional quantum walks produced by the broken-link-type noise and compare their robustness against the broken-link-type noise. Specifically, we analyze the quantum correlation between the two spatial dimensions x and y by using measurement-induced disturbance for the two-state quantum walks, i.e. the alternate walk and the Pauli walk, and the four-state quantum walks, i.e. the Grover, Hadamard and Fourier walks, respectively. Our analysis shows that the two-state walks are more robust against the broken-link-type noise than the four-state walks.

scholarly journals Freezing dynamics of entanglement and nonlocality for qutrit-qutrit (3 ⊗ 3) quantum systems

2019 ◽  
Vol 34 (13) ◽  
pp. 1950102 ◽  
Author(s):  
Mazhar Ali
Keyword(s):  
Finite Time ◽  
Quantum Systems ◽  
Quantum States ◽  
Multipartite Quantum Systems ◽  
Combined Action ◽  
Time Invariant ◽  
Decoherence Free Subspaces

We examine the possibilities of nontrivial phenomena of time-invariant entanglement and freezing dynamics of entanglement for qutrit-qutrit quantum systems. We find no evidence for time-invariant entanglement, however, we do observe that certain quantum states freeze their entanglement after decaying for some time. It is interesting that quantum states are changing whereas their entanglement remains constant. We find that the combined action of decoherence free subspaces and subspaces where quantum states decay, facilitate this phenomenon. This study is an extension of similar phenomena observed for qubit-qubit systems, qubit-qutrit, and multipartite quantum systems. We examine nonlocality of a specific family of states and find the certain instances where the states still remain entangled, however, they can either loose their nonlocality at a finite time or remain nonlocal for all times.

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