# Seminar at SMU Delhi

April 15, 2015 (Wednesday) , 3:30 PM at Webinar
Speaker: Ritabrata Sengupta, Indian Statistical Institute, Delhi
Title: From particle counting to tomography of Gaussian states and channels
Abstract of Talk
A quantum system assumed to be an unknown Gaussian state $\rho$ in the complex Hilbert space $L^2(\mathbb{R}^n)$, is determined my its momentum and position mean $(\mathbf{l}, \mathbf{m})$ and its covariance matrix $S$. To estimate the state, i.e. to estimate the parameters mentioned above, we shall use only counting measurements. This approach differs from the standard approach of using continuous variable measurement for Gaussian state estimation, available in literature. We also determine the optimal number of such measurements required for a $n$-mode unknown state. As a corollary, we show that, this method can be used for estimating an unknown Gaussian channel as well. This is an upcoming joint work with Prof K R Parthasarathy.