05.12.2017

Invitation to a talk by Roope Uola on Tuesday, December 5th 2017, 15:00h

Probing quantum steering through incompatible quantum measurements

Quantum steering refers to the possibility of one observer, say Alice, to remotely affect another observer’s, say Bob’s, ensemble of states by making only local measurements on her system. Also known as the spooky action at a distance, quantum steering is a type of correlation in between entanglement and non-locality. In order to achieve this quantum phenomenon, two ingredient are required: entanglement and incompatible quantum measurements. Whereas entanglement is necessary but not sufficient for steering, it turns out that incompatibility is both necessary and sufficient for the task. In my talk, I will show how our recent works have lead to this characterisation first for finite-dimensional scenarios in a rather straightforward way and then how the infinite- dimensional version can be found through a simple generalisation of the Choi-Jamiolkowski isomorphism. Moreover, I will discuss some of the implications of this connection such as a translation between steering inequalities and measurement uncertainty relations, a quantifier for incompatibility, and some examples of steering in the continuous variable case using position and momentum observables.