Title: Duistermaat-Heckman measure and mixture of adjoint orbits of quantum states
Speaker: Lin Zhang (张林)，Hangzhou Dianzi University
Abstract: In this paper, using a unifying treatment, we derive the spectral density of the mixture of adjoint orbits of quantum states in terms of Duistermaat-Heckman measure, originated from the theory of symplectic geometry. Some examples in lower dimensional space can be computed explicitly. As an application, we show that, in the two-level quantum system, the average entropy of the equiprobable mixture of three random density matrices chosen from a random state ensemble (specified in the text) is strictly larger than that of the equiprobable mixture of two random density matrices from the same ensemble. Hence, the quantum coherence monotonously decreases statistically as the mixing times $n$. This indicates that 'mixing reduces coherence'.
Time: 2018.07.13, 15:30--16:30, Place: 522, Gewu Building
