Glass lenses and mirrors appear perfectly smooth and still. But beneath the surface, a hidden life teems. Atoms in an amorphous material (a substance without a crystalline lattice) are packed haphazardly, and this disorder creates a complex energy landscape, like a mountainous region with countless hills and valleys.
Such materials always contain defects — places where atoms sit uncomfortably. Even weak vibrations can make them hop to more favorable positions. Previously, it was thought that each defect jumps on its own, like an independent stochastic switch. But new molecular simulations show that neighboring jumps are linked. One shift triggers another, resulting in a chain reaction. This is not a collection of independent two-level systems but a true network of interacting transitions.
The authors of the study did not just describe the problem. They performed a virtual anneal, a slow cooling of the material in simulation, and analyzed which pathways lose energy fastest. It turned out that by controlling the heating and cooling history, one can rearrange the defect network and significantly reduce friction even at room temperature. So future mirrors for gravitational wave hunters will be quieter, and thus more sensitive.
Amorphous materials like window glass actually flow, but unimaginably slowly — old glass is slightly thicker at the bottom than at the top due to flowing over centuries.
In Carl Sagan's novel "Contact," an alien signal is first detected by gravitational wave detectors — the more precise the mirrors, the farther we can hear the universe.