Credit: Vilasini & Renner
Decades ago, John Bell introduced Bell’s theorem, a renowned theoretical framework that defines the boundaries of classical physical processes based on relativistic causality principles rooted in Einstein’s theory of relativity. These principles govern how cause and effect function in the universe.
A recent study by researchers at Inria, Université Grenoble Alpes, and ETH Zurich delves into whether similar constraints apply to quantum processes. Published in Physical Review Letters (PRL), their paper unveils new theorems outlining fundamental limits that could impact the execution of quantum experiments within classical background spacetimes.
“Causality plays a pivotal role in our understanding of the world but manifests differently in two key physical theories: quantum theory and general relativity,” explained V. Vilasini, co-author of the study, to Phys.org.
“In quantum theory, causality pertains to information flow between systems and operations, while in general relativity, it is intertwined with spacetime structure. Surprisingly, quantum theory allows for ‘indefinite causal order’ (ICO) processes where events can exist simultaneously.”
To explore whether ICO processes—where sequential events lack a causal relationship—can manifest physically, researchers aim to connect these phenomena with established relativistic causality concepts within spacetime. This was the primary objective behind Vilasini and Renato Renner’s recent publication.
“We devised a theoretical framework that bridges these two causality concepts cohesively with minimal physical assumptions,” stated Vilasini. “This enabled us to derive comprehensive no-go theorems for any quantum experiment conducted within classical spacetime.”
2024-10-16 07:15:03
Source from phys.org