Matter waves and quantum splinters

Physicists in the United States, Austria and Brazil have shown that shaking ultracold Bose-Einstein condensates (BECs) can cause them to either divide into uniform segments or shatter into unpredictable splinters, depending on the frequency of the shaking.

“It’s remarkable that the same quantum system can give rise to such different phenomena,” said Rice University physicist Randy Hulet, co-author of a study about the work published online today in the journal Physical Review X. Hulet’s lab conducted the study’s experiments using lithium BECs, tiny clouds of ultracold atoms that march in lockstep as if they are a single entity, or matter wave. “The relationship between these states can teach us a great deal about complex quantum many-body phenomena.”

The research was conducted in collaboration with physicists at Austria’s Vienna University of Technology (TU Wien) and Brazil’s University of São Paulo at São Carlos.

The experiments harken to Michael Faraday’s 1831 discovery that patterns of ripples were created on the surface of a fluid in a bucket that was shaken vertically at certain critical frequencies. The patterns, known as Faraday waves, are similar to resonant modes created on drumheads and vibrating plates.

To investigate Faraday waves, the team confined BECs to a linear one-dimensional waveguide, resulting in a cigar-shaped BEC. The researchers then shook the BECs using a weak, slowly oscillating magnetic field to modulate the strength of interactions between atoms in the 1D waveguide. The Faraday pattern emerged when the frequency of modulation was tuned near a collective mode resonance.

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