Synopsis

Ripples and Fireworks in Bose-Einstein Condensates

Physics 11, s142
By switching a magnetic field’s direction up and down, researchers interfered matter waves to produce density ripples that led to firework-like jets.
H. Fu et al., Phys. Rev. Lett. (2018)

By manipulating interactions between ultracold atoms, physicists aim to better understand how the behavior of quantum particles leads to exotic phenomena such as topological states and quantum phase transitions. In 2017, researchers observed that a Bose-Einstein condensate (BEC) in an oscillating magnetic field emits jets that resemble fireworks. Now, Han Fu of the University of Chicago and colleagues have discovered that prior to the formation of the fireworks, distinctive ripples from interfering matter waves form in the condensate.

Using lasers and magnetic fields, the team condensed 40,000 cesium atoms onto a disk-shaped trap near absolute zero. When the experimenters switched the magnetic field direction up and down, they produced density waves analogous to standing waves that occur in contained classical fluids. The amplitudes of these density waves gradually increased until the BEC started to emit jets. The team noted that the evolution of the BEC proceeds in three steps: the appearance of density waves, the emergence of jets, and, finally, the presence of clearly defined jets.

Fu and colleagues modeled these steps to study how the density-wave amplitudes grow and how the waves may be related to the jets. The team found that in tens of milliseconds, the spatial distribution of a single firework mirrored that of the density waves that preceded it, which suggests that the waves are direct precursors of the jets and influence their shape. This model is one of the first theoretical frameworks for studying these unusual matter-wave jets.

This research is published in Physical Review Letters.

–Sophia Chen

Sophia Chen is a freelance science writer based in Tucson, Arizona.


Subject Areas

Atomic and Molecular Physics

Related Articles

A Laser-Free Method for Cooling Heavy Molecules
Atomic and Molecular Physics

A Laser-Free Method for Cooling Heavy Molecules

Electric deceleration brings a beam of the largest molecules yet to a standstill.   Read More »

Close Passes Give Atoms Tiny Quantum Kicks  
Atomic and Molecular Physics

Close Passes Give Atoms Tiny Quantum Kicks  

A new technique in which atoms move slowly through a diffraction grating lets researchers measure the tiny Casimir-Polder interaction, a force that arises from quantum vacuum fluctuations. Read More »

Quantum Control for Rydberg State Spectroscopy
Atomic and Molecular Physics

Quantum Control for Rydberg State Spectroscopy

Borrowing from techniques used for the quantum control of chemical reactions, researchers have developed a method to study the Rydberg states of molecular ions that are relevant to astrophysical plasma. Read More »

More Articles