Prof. Shunlong Luo, Academy of Mathematics and Systems Science Chinese Academy of Sciences
Abstract
Decoherence, interpreted broadly, is essentially the leakage of system information into environment, and is often accompanied by dissipation. The basic question arises as how to quantify decoherence induced by an operation, and how to quantitatively compare decoherence induced by different operations. In this talk, based on a joint ancilla-system-environment tripartite purification for the initial system state and the operation, and by exploiting the intrinsic relations between the loss of correlations in the ancilla-system and the correlations established in the system-environment, we characterize and quantify decoherence via decorrelation.
For this purpose, we first address the issue of separating and quantifying the classical and quantum parts of decorrelation. With the help of quantum decorrelation, we introduce an intuitive measure of (quantum) decoherence. We further employ these informational quantities to analyze some widely used channels. Our analysis illustrate the intriguing interplay between classical and quantum decorrelations, and shed some light on the informational nature of decoherence.