Mueller Research Group

Department of Physics

Laboratory of Atomic and Solid State Physics

Cornell UniversityIthaca, NY • 14853

em256@cornell.edu • (607)255-1568

Ultracold Atom Theory

Overview

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Vortex Ring Movie

News from our Group

  • Quantum Tsunamis are actually Smoke Rings

    By shining light on a gas cooled to temperatures near absolute zero, physicists can create waves that propagate through the gas while maintaining their shape - the quantum version of a tsunami traveling through the ocean. By studying the motion of these ``solitary waves" or ``solitons" one learns about the underlying interactions between the atoms in the gas. In particular, one can test theories about the quantum mechanics of many interacting particles, with applications ranging from understanding the properties of neutron stars to the behavior of electronic devices. In work reported in Nature [Yefsah et al. Nature 499, 426 (2013)], experimentalists at MIT found solitons that moved many times slower than any known model, suggesting holes in our understanding of nature. Following up on a suggestion of Aurel Bulgac and collaborators [Bulgac et al. arXiv:1306.4266, to appear in Physical Review Letters], our group [Reichl and Mueller, arXiv:1309.7012, to appear in Physical Review A] explains the observations by showing that the solitons rapidly break up into structures reminiscent of smoke rings. The slow motion of these ``vortex rings" is completely consistent with the experiments, which lack the resolution to distinguish between a tsunami and a smoke ring. This theoretical work will inspire further refinements in the experiments that will definitively identify the waves produced.

Research

[ Ultracold GasesVortices and Topological DefectsBEC-BCS CrossoverRF SpectroscopyPublicationsPresentations ]
simulation of interference between atomic clouds

Ultracold Gases

At room temperatures the behavior of a gas of atoms is dominated by their random thermal motion. Averaged over time this gives simple descriptions in terms of thermodynamic variables such as Temperature and Pressure. As the temperature is lowered, this thermal motion is reduced. The Heisenberg uncertainty principle prevents the atoms from coming to a stop. Instead, at nanokelvin temperatures, quantum mechanics dictates the properties of these atomic gases. We study this strange and beautiful form of quantum matter. (more)