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Paper 1
Locally inequivalent four qubit hypergraph states
Xiao-yu Chen, Lei Wang
- Year
- 2014
- Journal
- arXiv preprint
- DOI
- arXiv:1409.0928
- arXiv
- 1409.0928
Hypergraph states as real equally weighted pure states are important resources for quantum codes of non-local stabilizer. Using local Pauli equivalence and permutational symmetry, we reduce the 32768 four qubit real equally weighted pure states to 28 locally inequivalent hypergraph states and several graph states. The calculation of geometric entanglement supplemented with entanglement entropy confirms that further reduction is impossible for true hypergraph states.
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M Times Photon Subtraction-Addition Coherent Superposition Operated Odd-Schrődinger-cat State: Nonclassicality and Decoherence
Li Huang, Qin Guo, Li-ying Jiang, Ge Chen, Xue-xiang Xu, Wen Yuan
- Year
- 2014
- Journal
- arXiv preprint
- DOI
- arXiv:1407.7104
- arXiv
- 1407.7104
We introduce a new non-Gaussian state, generated by m times coherent superposition operation $a\cos θ+a^{\dagger }e^{i\varphi }\sin θ$ (MCSO) on odd-Schrodinger-cat state (OSCS). Its normalized constant is turned out to be related with the Hermite polynomial. We further investigate the nonclassical properties of the MCSO-OSCS through Mandel's Q-parameter, quadrature squeezing, the photocount distribution and Wigner function (WF). It is shown that the nonclassicality of the MCSO-OSCS is influenced by the number of times (m) of coherent superpositon operation, the angle $θ$ and the amplitude of the coherent state (|$α_{0}$|). Especially the volume of negative region of WF increases with the increment of parameters m, $θ$ and $α_{0}$. We also investigate the decoherence of the MCSO-OSCS in terms of the fadeaway of the negativity of WF in a thermal environment.
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