Quantum Gas Lab  @ Seoul National University

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We are an experimental research group in the Department of Physics and Astronomy, Seoul National University. Our group studies ultracold gases to investigate collective quantum phenomena such as Bose-Einstein condensation and superfluidity. Quantum gases are highly controllable and clean systems, presenting a new experimental avenue for fundamental study of quantum many-body physics. Our goal is to exploit and develop various quantum gas systems to search for new states of matter and to address challenging problems in condensed matter physics.

 

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Position Openings

If you are interested in joining us, please send your inquiry to yishin(at)snu.ac.kr .

 

 

 

Recent Research Highlights

 

 

Critical Spin Superflow in a Spinor Bose-Einstein Condensate

Physical Review Letters 119, 185302 (2017)

We investigate the critical dynamics of spin superflow in an easy-plane antiferromagnetic spinor Bose-Einstein condensate. Spin-dipole oscillations are induced in a trapped condensate by applying a linear magnetic field gradient and we observe that the damping rate increases rapidly as the field gradient increases above a certain critical value. The onset of dissipation is found to be associated with the generation of dark-bright solitons due to the modulation instability of the counterflow of two spin components. Spin turbulence emerges as the solitons decay because of their snake instability. We identify another critical point for spin superflow, in which transverse magnon excitations are dynamically generated via spin-exchanging collisions, which leads to the transient formation of axial polar spin domains.

 

 

 

Strongly interacting Fermi superfluid of 6 Li atoms across the BEC-BCS crossover has been observed on Feburary 9th, 2017!!

First Strongly interacting Fermi superfluid in Korea !!

 

 

 

Observation of von Kármán Vortex Street in an Atomic Superfluid Gas

Physical Review Letters 117, 245301 (2016)

We report on the experimental observation of vortex cluster shedding from a moving obstacle in an oblate atomic Bose-Einstein condensate. At low obstacle velocities v above a critical value, vortex clusters consisting of two like-sign vortices are generated to form a regular configuration like a von Kármán street, and as v is increased, the shedding pattern becomes irregular with many different kinds of vortex clusters. In particular, we observe that the Stouhal number associated with the shedding frequency exhibits saturation behavior with increasing v. The regular-to-turbulent transition of the vortex cluster shedding reveals remarkable similarities between a superfluid and a classical viscous fluid. Our work opens a new direction for experimental investigations of the superfluid Reynolds number characterizing universal superfluid hydrodynamics.

Related articles in Viewpoint in Physics and Physics Today

 

 

 

 

QGL@SNU,  Seoul 151-747, Korea. Tel +82(2)880-4233