Decoherence of a qubit as a diffusion on the Bloch sphere
arXiv:1506.06292 · doi:10.1088/1751-8113/48/40/405202
Abstract
We analyze qubit decoherence in the framework of geometric quantum mechanics. In this framework the qubit density operators are represented by probability distributions which are also the Kähler functions on the Bloch sphere. Interestingly, the complete positivity of the quantum evolution is recovered as ellipticity of the second order differential operator (deformed Laplacian) which governs the evolution of the probability distribution.