QLunch: Thor Gabelgaard Nielsen

Speaker: Thor Gabelgaard Nielsen

Title: Convex self-testing of Glued Magic Games


Self-testing results allows one to characterise the quantum state and
measurements used in some systems by only observing outputs produced by
non-communicating parties. However, the usual notion of self-testing
for nonlocal games only encompasses situations where there is a single
optimal strategy, and is shown not to apply for the Glued Magic Square
game, first defined by Cui et al. We generalise self-testing to allow
for multiple optimal inequivalent strategies, and show that the Glued
Magic Square self-tests a convex combination of inequivalent
strategies. Furthermore we obtain that it self-tests two EPR pairs in
the usual sense, and the self-test we obtain is both robust and extends
to natural generalisations of the Glued Magic Square game.
This is a joint work with Laura Mančinska and Jitendra Prakash.