Linear vs non-linear – Gaussian state discrimination

Linear vs non-linear – Gaussian state discrimination

Seminar author:Andreas Winter

Event date and time:04/29/2014 02:30:pm

Event location:IFAE seminar room

Event contact:

 I will present the main result from a paper by Takeoka and Sasaki [PRA 78:022320, 2008], which says that to distinguish two coherent quantum states of a single mode, there is a difference between the optimal (Helstrom) measurement, which is non-linear, and what can be achieved by Gaussian operations and classical information processing (GOCC). The optimum strategy from the latter class is simply the homodyne measurement of the quadrature direction along the line connecting the two phase space expectations.
The gap is small, though, and even smaller when certain simple non-linear optical elements are allowed. I then plan to discuss ideas for obtaining a large gap between ALL measurements and GOCC, a kind of linear optical data hiding.