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.

 

ڱü Ұ

  

 

Position Openings

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

 

 

 

Recent Research Highlights

 

 

Collisional Dynamics of Half-Quantum Vortices in a Spinor Bose-Einstein Condensate

Physical Review Letters 116, 185301 (2016)

We present an experimental study on the interaction and dynamics of half-quantum vortices (HQVs) in an antiferromagnetic spinor Bose-Einstein condensate. By exploiting the orbit motion of a vortex dipole in a trapped condensate, we perform a collision experiment of two HQV pairs, and observe that the scattering motions of the HQVs is consistent with the short-range vortex interaction that arises from nonsingular magnetized vortex cores. We also investigate the relaxation dynamics of turbulent condensates containing many HQVs, and demonstrate that spin wave excitations are generated by the collisional motions of the HQVs. The short-range vortex interaction and the HQV-magnon coupling represent two characteristics of the HQV dynamics in the spinor superfluid.

 

 

 

Half-Quantum Vortices in an Antiferromagnetic Spinor Bose-Einstein Condensate

Physical Review Letters 115, 015301 (2015)

We report on the observation of half-quantum vortices (HQVs) in the easy-plane polar phase of an antiferromagnetic spinor Bose-Einstein condensate. Using in situ agnetization-sensitive imaging, we observe that pairs of HQVs with opposite core magnetization are generated when singly charged quantum vortices are injected into the condensate. The dynamics of HQV pair formation is characterized by measuring the temporal evolutions of the pair separation distance and the core magnetization, which reveals the short-range nature of the repulsive interactions between the HQVs. We find that spin fluctuations arising from thermal population of transverse magnon excitations do not significantly affect the HQV pair formation dynamics. Our results demonstrate the instability of a singly charged vortex in the antiferromagnetic spinor condensate.

 

 

 

Bose-Einstein condensation of 174 Ytterbium atoms has been observed on Nov 21st, 2014!!

 

 

 

Relaxation of superfluid turbulence in highly oblate Bose-Einstein condensates

Physical Review A 90, 063627 (2014)

 

We investigate thermal relaxation of superfluid turbulence in a highly oblate Bose-Einstein condensate. The turbulent condensate shows a spatially disordered distribution of quantized vortices, and the vortex number of the condensate exhibits nonexponential decay behavior which we attribute to the vortex pair annihilation.

 

 

 

 

 

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