Liquids in the body's drainage system can be pumped more effectively when the 'pumping wave' moves in the opposite direction of the flow.
March 31, 2026
Original Paper
Unidirectional flow from continuous broken symmetries
arXiv · 2603.27474
The Takeaway
By studying the human lymphatic system, researchers found a counterintuitive rule: fluid is often moved forward most efficiently by waves that propagate backward. This discovery explains how biological systems move fluids through complex channels without traditional motors and defies basic engineering intuition about how pumps work.
From the abstract
Locally broken symmetries are used across fields to transport matter, particles and information in preferential directions. Beyond local mechanisms, spatially distributed nonlinearities in crystalline media have enabled non-reciprocal transport, a rectification mechanism that operates continuously across scales and frequencies. Here, we show that this concept applies beyond condensed matter, to fluid transport in living organisms and artificial systems. We take the example of the lymphatic vascu