Experimental investigation and robustness of Ardehali inequality in four-photon six-qubit Greenberger-Horne-Zeilinger state

Abstract

By exploiting both the photons’ polarization and spatial degrees of freedom, we experimentally demonstrate a hyper-entangled four-photon six-qubit Greenberger-Horne-Zeilinger (GHZ) state. Based on the state, we experimentally test the multi-particle Ardehali inequality and prove the theoretical prediction of Ardehali. Furthermore, we experimentally first investigate the robustness of the Ardehali inequality for the four-photon six-qubit GHZ state in a bit-flip noise environment and show the good robustness against decoherence for this inequality. Our works provide an experimental benchmark to estimate the safety of quantum channel in the noisy environment.

Keywords:

• hyper entangled
• Ardehali inequality
• bit-flip noise
• robustness

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 11174224], [grant number 11404246], [grant number 11447225]; the Science and Technology Development Program of Shandong Province [grant number 2013YD01016]; the Natural Science Foundation of Shandong Province [grant number BS2015DX015], [grant number 2013SJGZ10]; Higher School Science and Technology Program of Shandong Province [grant number J13LJ54], [grant number J15LJ54].