A continuous-time diffusion limit theorem for dynamical decoupling and intrinsic decoherence

作者：Hillier Robin^*; Arenz Christian; Burgarth Daniel

来源：Journal of Physics A-Mathematical and Theoretical, 2015, 48(15): 155301.

DOI：10.1088/1751-8113/48/15/155301

• central limit theorem
• dynamical decoupling
• intrinsic decoherence
• CPT semigroups

We discuss a few mathematical aspects of random dynamical decoupling, a key tool procedure in quantum information theory. In particular, we place it in the context of discrete stochastic processes, limit theorems and completely positive trace-preserving semigroups on matrix algebras. We obtain precise analytical expressions for expectation and variance of the density matrix and fidelity over time in the continuum-time limit depending on the system Lindbladian, which then lead to rough short-time estimates depending only on certain coupling strengths. We prove that dynamical decoupling does not work in the case of intrinsic (i.e., not environment-induced) decoherence, and together with the above-mentioned estimates this yields a novel method of partially identifying intrinsic decoherence.

• 出版日期2015-4-17