Physicists have conducted experiments demonstrating 'indefinite causal order' in quantum mechanics, where events can exist in a superposition of different temporal sequences. The research shows that the question of whether event A or B happened first can become probabilistic rather than deterministic. While some experimental loopholes remain, this challenges fundamental assumptions about causality in quantum systems.
Background
Quantum mechanics has long challenged classical notions of causality, with phenomena like quantum entanglement suggesting that measurements can appear to influence events retroactively. The concept of indefinite causal order explores whether the sequence of events in quantum systems can exist in superposition.
- Source
- Ars Technica
- Published
- Mar 28, 2026 at 08:00 PM
- Score
- 8.0 / 10