Researchers investigate ‘imaginary part’ in quantum resource theory

Experimental setup for local state discrimination.

A research team led by the University of Science and Technology of China (USTC), has made important progress in quantum information theory.

The question of whether complex structures are necessary for quantum mechanics has long been debated by physicists. Researchers have regarded the complex number as a kind of quantum resource, and reveal its irreplaceable role in the local discrimination of bipartite quantum states.

Using the two-photon entangled state prepared by parametric down conversion, researchers further measured and compared the success probability of locally distinguishing quantum state when only using the real measurement basis and general measurement basis. They successfully observed the increase of the success probability when using the complex measurement basis, which verified the important role of the complex in quantum mechanics.

The results have been jointly published in Physical Review Letters and Physical Review A.

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