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arXiv · 1701.08749

Schrödinger cat and Werner state disentanglement simulated by trapped ion systems

Victor A. S. V. Bittencourt·Alex E. Bernardini
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Abstract

Disentanglement and loss of quantum correlations due to one global collective noise effect are described for two-qubit Schrödinger cat and Werner states of a four level trapped ion quantum system. Once the Jaynes-Cummings ionic interactions are mapped onto a Dirac spinor structure, the elementary tools for computing quantum correlations of two-qubit ionic states are provided. With two-qubit quantum numbers related to the total angular momentum and to its projection onto the direction of an external magnetic field (which lifts the degeneracy of the ion's internal levels), a complete analytical profile of entanglement for the Schrödinger cat and Werner states is obtained. Under vacuum noise (during spontaneous emission), the two-qubit entanglement in the Schrödinger cat states is shown to vanish asymptotically. Otherwise, the robustness of Werner states is concomitantly identified, with the entanglement content recovered by their noiseless-like evolution. Most importantly, our results point to a firstly reported sudden transition between classical and quantum decay regimes driven by a classical collective noise on the Schrödinger cat states, which has been quantified by the geometric discord.

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Victor A. S. V. Bittencourt, Alex E. Bernardini. 2017-01-30. Schrödinger cat and Werner state disentanglement simulated by trapped ion systems. https://doi.org/10.1088/1361-6455%2Faa60df

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