Experimental entanglement of temporal order
Abstract
The study of causal relations has recently been applied to the quantum realm, leading to the discovery that not all physical processes have a definite causal structure. While indefinite causal processes have previously been experimentally shown, these proofs relied on the quantum description of the experiments. Yet, the same experimental data could also be compatible with definite causal structures within different descriptions. Here, we present the first demonstration of indefinite temporal order outside of quantum formalism. We show that our experimental outcomes are incompatible with a class of generalised probabilistic theories satisfying the assumptions of locality and definite temporal order. To this end, we derive physical constraints (in the form of a Bell-like inequality) on experimental outcomes within such a class of theories. We then experimentally invalidate these theories by violating the inequality using entangled temporal order. This provides experimental evidence that there exist correlations in nature which are incompatible with the assumptions of locality and definite temporal order.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 11, 2022
- Source ID
- 10.22331/q-2022-01-11-621
Entities
People
- Francesco Massa
- Giulia Rubino
- Lee A. Rozema
- Magdalena Zych
- Mateus Araújo
- Philip Walther
- Časlav Brukner
Organizations
- Air Force Office of Scientific Research
- Austrian Academy of Sciences
- Austrian Science Fund
- European Commission
- Royal Society
- Templeton World Charity Foundation
- University of Bristol
- University of Queensland
- University of Vienna