QLunch: Daniel Stilck França

Speaker: Daniel Stilck França from QMATH

Title: Fast and robust quantum state tomography from few basis measurements

Abstract: Quantum state tomography is a powerful, but resource-intensive, general solution for numerous quantum information processing tasks. This motivates the design of robust tomography procedures that use relevant resources as sparingly as possible. Important cost factors include the number of state copies and measurement settings, as well as classical postprocessing time and memory. In this work, we present and analyze an online tomography algorithm that is designed to optimize all the aforementioned resources at the cost of a worse dependence on accuracy. The protocol is the first to give optimal performance in terms of rank and dimension for state copies, measurement settings and memory. Classical runtime is also reduced substantially. Further improvements are possible by executing the algorithm on a quantum computer, giving a quantum speedup for quantum state tomography. 

This is joint work with Fernando Brandao and Richard Kueng.