Quantum Tunnelling

National Cycle Network Route 4 heads through a concrete wall
Bill Gannon

Quantum mechanics predicts that a particle has a finite probability of appearing on the other side of any physical barrier, regardless of its height or width. Quantum tunnelling is a consequence of the wave-particle duality of matter and is often explained using the Heisenberg uncertainty principle.

Traditionally this has only been of interest of particle physicists, but recently, highway engineers realised that they could exploit the quantum wave like properties of cyclists to create a tunnel on National Cycle Network Route 4 in Wales, without all the expensive civil engineering works involved in digging a hole.