All You Need to Know about Indefinite Causal Orders

Seminar author:Hippolyte Dourdent

Event date and time:05/04/2023 02:30:pm

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While the standard formulation of quantum theory assumes a fixed background causal structure, the process matrix formalism allows to relax this assumption and explore the possibility of processes with indefinite causal orders.        For example, one may imagine a quantum circuit in which the order between Alice and Bob’s operations on a target qubit is coherently controlled by another quantum system, such that their operations are in a superposition of causal orders. After introducing the notions of causal nonseparability and noncausality– formalizing the notion of indefinite causal orders – and their certifications, I will present the most relevant causally nonseparable processes, and give examples of applications for quantum information.