Quantum particles can slip through obstacles like a ball that suddenly finds itself inside a hill and pops out the other side. This tunnel effect, a direct consequence of the wave nature of matter, was explained by George Gamow when he cracked the mechanism of alpha decay: how particles escape the atomic nucleus by overcoming a potential barrier. New research shows that if this "hill" wobbles, its height fluctuating randomly due to external vibrations, particles find it harder to get through. Noise injects entropic chaos: it scrambles the coherent motion of the particle's wave, destroying the interference needed for tunneling, and the ball bounces back more often.

The suppression is especially striking in graphene — a two-dimensional sheet of carbon just one atom thick. There, electrons behave like massless relativistic particles zipping along at nearly the speed of light. Normally, they sail through any potential barrier thanks to the Klein effect, a quantum-relativistic phenomenon where a particle passes through an obstacle without reflection, but a jittering barrier breaks that invincibility. Even a head-on attack, with the electron hitting the barrier perpendicularly, now sends it bouncing back. The reason is that the fluctuations make the inside of the "hill" unstable: the phase of the particle's wave gets scrambled, and the tunneling probability drops sharply. The researchers figured this out by analyzing solutions to the Dirac equation for graphene with stochastic noise added to the barrier potential.

Such a noise gate, controlled suppression of tunneling via engineered fluctuations, opens the door to precise quantum switches for future computers. In these, individual electrons could be steered without ultra-complex cooling systems or magnetic traps. As John Preskill noted, control over single quantum objects is the foundation of the computational leap toward practical quantum technologies. Ironically, interference, usually associated with destroying order, becomes a tool for ordering: noise can block unwanted tunneling and thereby set a clear switch state.