We invite you to participate in the first QTalk in Pakistan. We will host Amin Shiraz Gilani with a lecture on Unlimited non-causal correlations and its relation to non-locality. He will talk about whether causal order arises in the limit of multi-particle correlations for any number of parties. Amin has presented his earlier research at QIP 2018 and 2020, the latter earning him the best poster award.
QTalk will take place at 15:00 (GMT), Wednesday, January 20, 2021. The event will be delivered as a Zoom meeting. Registration form is avaiable at http://bityl.pl/xvDQ4
From Amin: The traditional notion of causal order dictates that a space-time event cannot influence any event in its past. There exist motivations to relax this notion from the quest to combine general relativity with quantum theory. This has led to the search for physical principles that re-establish causal order. We ask whether causal order arises in the limit of multi-particle correlations and find multi-party non-causal correlations for any number of parties that are in agreement with all principles thus far posed. However, these correlations violate a family of causal inequality maximally, while under the assumption of causal order the corresponding game can at most be won with probability half in the limit of the number of parties. This implies that the space of logically consistent correlations is infinitely larger than the space of correlations based on the assumptions of causal order. The game is closely related to Ardehali-Svetlichny nonlocal game. We leave open the search for reasonable principles that establish causal order. It seems that as of today, the only way to establish causal order is to assume it.