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arXiv · 0912.4654

Decoherence and Entanglement Dynamics in Fluctuating Fields

Julius Helm·Walter T. Strunz
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Abstract

We study pure phase damping of two qubits due to fluctuating fields. As frequently employed, decoherence is thus described in terms of random unitary (RU) dynamics, i.e., a convex mixture of unitary transformations. Based on a separation of the dynamics into an average Hamiltonian and a noise channel, we are able to analytically determine the evolution of both entanglement and purity. This enables us to characterize the dynamics in a concurrence-purity (CP) diagram: we find that RU phase damping dynamics sets constraints on accessible regions in the CP plane. We show that initial state and dynamics contribute to final entanglement independently.

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Julius Helm, Walter T. Strunz. 2009-12-23. Decoherence and Entanglement Dynamics in Fluctuating Fields. https://doi.org/10.1103/physreva.81.042314

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