Środowiskowe Seminarium z Informacji i Technologii Kwantowych
sala 1.03, ul. Pasteura 5
2023-01-26 (11:15) 
Kacper Dębski (IFT UW)
Indefinite temporal order without gravity
ONSITE ONLY
According to the general theory of relativity, time can flow at different rates depending on the configuration of massive objects, affecting the temporal order of events. Combined with quantum theory, this gravitational effect can result in events with an indefinite temporal order when a massive object is prepared in a suitable quantum state. This was argued to lead to a theory-independent test of the non-classical order of events through the violation of Bell-type inequalities for temporal order. The theory-independence of this protocol is problematic: one of the auxiliary assumptions in the above approach turns out to be essential, while it is explicitly theory-dependent. To illustrate this problem we can construct a complete scenario where accelerating particles interacting with optical cavities result in a violation of temporal Bell inequalities. Due to the Equivalence Principle, this scenario is fully analogous to the gravitational case, yet avoids the criticism raised in the context of gravitational effects arising from quantum states of massive bodies, that we do not have a full framework describing such scenarios.
According to the general theory of relativity, time can flow at different rates depending on the configuration of massive objects, affecting the temporal order of events. Combined with quantum theory, this gravitational effect can result in events with an indefinite temporal order when a massive object is prepared in a suitable quantum state. This was argued to lead to a theory-independent test of the non-classical order of events through the violation of Bell-type inequalities for temporal order. The theory-independence of this protocol is problematic: one of the auxiliary assumptions in the above approach turns out to be essential, while it is explicitly theory-dependent. To illustrate this problem we can construct a complete scenario where accelerating particles interacting with optical cavities result in a violation of temporal Bell inequalities. Due to the Equivalence Principle, this scenario is fully analogous to the gravitational case, yet avoids the criticism raised in the context of gravitational effects arising from quantum states of massive bodies, that we do not have a full framework describing such scenarios.