Abstract
By investigating the effect of environmental perturbations on two initially coupled qubits, we find that the interactions between the qubits and between the qubits and the environment are not only the source of decoherence, but also the power of avoiding disentanglement. It is shown that there are the entangled subspaces for four kinds of different coupling ways between the qubits, in which the qubits preserve entanglement all the time. Thus, any new coherent source does not be introduced to preserve entanglement in the entangled subspaces.
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Acknowledgements
This work was supported by National Natural Science Foundation of China under Grant No. 11075119, the Fundamental Research Funds for the Central Universities under Grant No. 20102020101000019 and Foundation of Science and Technology of Education Office of Jiangxi Province under Grant No. GJJ10404.
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Chen, Z.Q., Guo, L. & Wang, Z.S. Entangled Subspaces for Two Coupled Qubits in a Normal Environment. Int J Theor Phys 51, 1022–1029 (2012). https://doi.org/10.1007/s10773-011-0976-7
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DOI: https://doi.org/10.1007/s10773-011-0976-7