Filter functions in quantum phase space representations.

Seminar author:Mani Zartab

Event date and time:2022-03-03 03:00

Event location:GIQ & Zoom

Event contact:

Continuous-variable (CV) representation of quantum mechanics plays a major role in quantum information theory and quantum optics, espe- cially in quantum state and process tomography. As an example, one might consider inferring the non-classicality of an unknown state, based on whether or not it can be written as a statistical mixture of classical (coher- ent) states. However, there is a major challenge here: the weight function (P-function) is a highly singular function for most cases. Here is where the concept of filtering is useful. It is possible to filter the Fourier transform of the P-function (normally-ordered characteristic function) such that the P- function becomes regularized, and also reveals the non-classicality of the original state as negative values. However, there are two subjects that remained open. First, a cohesive mathematical requirements to build a physical filter, and second, how much resemblance exists between the orig- inal state and the filtered state. These two questions are addressed by the work that will be explained in the talk (Zoom link)