平成15年度 第7回
物理教室談話会


題目
Multiquantum Vortices in Superconductors and 
Bose-Einstein Condensates
講師 Professor  Martti M. Salomaa
( Helsinki University of Technology )
日時 9月 8 日(月)16:00 - 17:00
場所 コラボレーションセンター 3階 コラボレーション室
岡山大学津島キャン パス内
要旨  Multiquantum vortices (MQV) have been observed using electron holography in type-I superconducting thin films at high magnetic fields. We have computed superconducting quasiparticle excitation spectra for m times quantized flux lines using a self-consistent Bogoliubov-de Gennes approach. We find m discrete branches of bound-state solutions in the spectrum. Owing to the bound states, the STM spectrum of the vortex is predicted to display m rows of peaks as a function of the distance from the vortex axis.
 
 We have also studied multiply quantized vortices in trapped Bose-Einstein condensates using the Bogoliubov theory. Suitable combinations of a localized pinning potential and external rotation of the system are found to energetically stabilize vortices with multiple circulation quanta. We present a phase diagram for stable multiply quantized vortices in terms of the angular rotation frequency of the system and the width of the pinning potential. We argue that MQVs could be created experimentally in BECs.  

 
世話人 理学部物理学科 町田 一成 (TEL: 086-251-7814) 



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