Southwest Quantum Information and Technology

Observation of a non-local reality in local post-selected systems via variable strength measurements

Presenting Author: Noah Lupu-Gladstein, University of Toronto
Contributing Author(s): Ou Teen Arthur Pang, Hugo Ferretti, Weng-Kian Tham, Kent Bonsma-Fisher, Aharon Brodutch, Aephraim M. Steinberg

We implement a variant of the quantum pigeonhole paradox experiment to study the relation between measurement results and physical reality. Our results highlight the subtleties of quantum measurements on pre- and post-selected systems (i.e., those with a fixed past and future). By implementing two different strategies to measure the same observable at different strengths we show that weak values, the ensemble averaged results of weak measurements, can be treated as consistent objective properties of the system. Furthermore, we observe how the procedure that leads to a complex weak value can (and should) be extended to the strong regime, albeit with an unclear interpretation. Finally, we show that for fixed pre and post selections, some operators can be replaced by real numbers when used in a Hamiltonian. Surprisingly, these can be non-local even when the pre and post selected states are completely local. To measure such non-local observables we implement the first variable strength non-local measurements using a technique that can be extended to other optical scenarios that require effective three body Hamiltonians.

(Session 5 : Saturday from 5:00pm - 7:00pm)