The Quantum State Over Time is unique!

Have you ever been puzzled by the fact that, while classical theory treats spatial and temporal correlations on equal footing, quantum theory doesn’t? If so, you’re not alone. There’s been a growing effort to develop a quantum framework that treats space and time symmetrically.

In our recent work, Seokhyung and Nelly dove into this challenge, and critically examined existing approaches and identified gaps in the foundational axioms proposed so far. Building on this, we formulated a new, minimal set of physically essential axioms that uniquely select the “Fullwood-Parzygnat state over time” as the consistent object for describing quantum correlations across time.

Check out our exploration in the preprint.

Update: this work has since been published in Phys. Rev. Research 6, 033144 (2024).