Tibetan singing bowls: levitation via resonance

The dynamics of fluid-filled Tibetan bowls was the  research subject of Denis Terwagne during his internship in the Applied Math Lab. Our combined experimental and theoretical investigation elucidated the manner in which the rubbing of the bowl excites its resonant wave modes, which in turn excite Faraday waves on the fluid surface that may break, giving rise to the ejection of droplets that bounce in place or skip across the free surface.

See paper here: Terwagne & Bush (2011)


And he showed Pierre a globe, a quivering ball of no dimensions, its surface consisting of drops tightly packed together. The drops moved and shifted, now merging from several into one, now dividing from one into many. Each drop strove to spread and take up the most space, but the others, striving to do the same, pressed against it, sometimes destroying, sometimes merging.  “This is life”, said the old teacher. “In the center is God, and each drop strives to expand in order to reflect Him in the greatest measure. It grows, merges and shrinks, is obliterated on the surface, vanishes into the depths, then resurfaces.”   – Leo Tolstoy, War and Peace, 1865


SELECT PRESS:  Nature News Blog , BBC News , UniverScience , Sciences et Sante

Quantum mechanics writ large


According to pilot wave theory, first proposed by de Broglie and later developed by Bohm with Einstein’s encouragement, microscopic elements such as photons and electrons consist of both particle and wave, the former being guided by the latter. Although this physical picture has not been widely accepted, it has had some notable proponents, including John Bell. Its principal appeal is that it restores realism and determinism to quantum mechanics, its weakness that the physical nature of the guiding wave field was not made clear. At the time that pilot wave theory was developed and then overtaken by the Copenhagen interpretation as the standard view of quantum mechanics, there was no macroscopic pilot wave analog to draw upon. Now there is.

See paper:  Bush, PNAS (2010)

Select Press: MIT News










 “Bein ere ez dena, izaten al da.”

Motivation: hydrodynamic quantum analogs

Yves Couder, Emmanuel Fort and coworkers have discovered a hydrodynamic system that exhibits certain features previously thought to be exclusive to the microscopic, quantum realm: droplets walking on a vibrating fluid bath.