Scientists discovered a liquid state where time essentially flows both ways, making the fluid's path look the same forward and backward.
April 1, 2026
Original Paper
Temporal reversibility of a fluid mixture under concentration gradient
arXiv · 2603.29027
The Takeaway
Usually, mixing something is a one-way street (entropy), but this study found a specific scenario where a liquid mixture remains 'time-reversible' even when being pushed. It proves that under certain conditions, the molecular path of a fluid can defy the traditional 'arrow of time.'
From the abstract
A binary fluid mixture in contact with lateral particle reservoirs is considered. By imposing different particle concentrations in these reservoirs, the system can be maintained under controlled non-equilibrium conditions. Previous stochastic approaches have revealed an unexpected property of the system's state trajectory, namely that it remains time-reversible even when the system is driven out of equilibrium. In the absence of relevant experimental evidence, we employ microscopic molecular dyn