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›› 2009, Vol. 26 ›› Issue (4): 569-576.DOI: 10.7523/j.issn.2095-6134.2009.4.020

• Excerpt of Dissertation • Previous Articles    

Experimental preparation and manipulation of quantum entangled states

HUANG Yun-Feng, GUO Guang-Can   

  1. Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
  • Received:2008-04-24 Online:2009-07-15

Abstract:

This paper presents our experimental work on preparing and manipulating quantum entangled states in optical quantum information processing systems. The main contents are: (1) Using continuous wave(CW) laser beam to pump nonlinear crystals we successfully prepared two-photon polarization entangled states with high brightness and entanglement degree, and it is tunable in entanglement degree and we use this source to produce one kind of important mixed states——Werner states with tunable entanglement fraction in it. (2) We realized the 1→2 qubits Buek-Hillery cloning machine with linear optical devices and showed that the fidelities between the two output qubits and the original qubit are both 5/6 for arbitrary input pure states. (3) We presented a method to test the maximal violation of the CHSH inequality for non-maximally entangled pure states and experimentally realized it with our entangled state source. (4) We perform an all-or-nothing-type Kochen-Specker experiment to verify whether non-contextual hidden variables (NCHV) or quantum mechanics is right. The results strongly agree with quantum mechanics.

Key words: entangled photons, spontaneous parametric down conversion (SPDC), quantum entanglement manipulation

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