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2002 Fiscal Year Final Research Report Summary

All-optical realization of quantum degeneracy of Yb atoms

Research Project

Project/Area Number 13640403
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 物理学一般
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

TAKAHASHI Yoshiro  KYOTO UNIVERSITY, PHYSICS, ASSOCIATE PROFESSOR, 大学院・理学研究科, 助教授 (40226907)

Co-Investigator(Kenkyū-buntansha) KUMAKURA Mitsutaka  KYOTO UNIVERSITY, PHYSICS, ASSISTANT, 大学院・理学研究科, 助手 (30324601)
YABUZAKI Tsutomu  KYOTO UNIVERSITY, PHYSICS, PROFESSOR, 大学院・理学研究科, 教授 (60026127)
Project Period (FY) 2001 – 2002
KeywordsLASER COOLING / BOSE CONDENSATION / OPTICAL TRAP / Yb ATOM / Yb MOLECULE / INJECTION LOCK / EVAPORATIVE COOLING / LASER DIODE
Research Abstract

BECs of two-electron atoms such as ytterbium (Yb) and alkali-earth atoms have distinct features such as the extremely narrow intercombination transitions which are ideal for future optical frequency standard and the insensitivity to external magnetic field which is important for precision coherent atom optics. Here we report the achievement of BEC of Yb atoms by all-optical means in a novel crossed far-off resonant trap (FORT). The evaporative cooling is carried out by gradually decreasing the horizontal FORT beam power in 2 sec., while keeping the vertical FORT beam power constant. When the final trap depth is 2.2 ,, K, anisotropic expansion after release from the trap has appeared. The number of atoms in the condensate is typically 5×10^3. The critical temperature is about 0.7 ,, K and the peak atom density is 7×10^<14> cm^<-3>. The lifetime of the condensate is about 500 ms, and we infer an upper bound for the three-body loss coefficient of 4×10^<-30> cm^6 s^<-1>.
From the behavior of the condensate, we have estimated the scattering length of ^<174>Yb. The chemical potential of 0.55, K is obtained from the fit with the horizontally expanded widths at ten TOF times, which gives the scattering length of 6 nm with the uncertainty of -5 and +10 nm. By combining this result with our recent photoassociation experiment, we conclude that the scattering length is between 1 to 3 nm.
The existence of rich varieties of stable isotopes of five bosons (^<168>Yb, ^<170>Yb, ^<172>Yb, ^<174>Yb, and ^<176>Yb) and two fermions (^<171>Yb and ^<173>Yb) will allow us to study various interesting quantum degenerate gases using Yb atoms. In addition, the successful demonstration of Yb BEC in the present work would also promise the formation of BEC of alkali-earth atoms.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] K.Honda et al.: "Optical dipole force trapping of a fermion-boson mixture of ytterbium"Phys.Rev. A. 66・2. 021401-1-021401-4(R) (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Enomoto et al.: "Emission spectra of Cs-He excimers in cold helium gas"Phys.Rev. A. 66・4. 042505-1-042505-4 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.Takasu et al.: "High-density trapping of cold ytterbium atoms by an optical dipole force"Phys.Rev.Lett.. 90・2. 023003-1-023003-4 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Toyoda et al.: "Generation of Bose-Einstein condensates in a well isolated low-pressure vacuum chamber"J. Phys. Soc. Jpn.. 71・6. 1445-1449 (2002)

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      「研究成果報告書概要(和文)」より
  • [Publications] Y.Takahashi et al.: "Photoassociation of laser cooled ytterbium atoms"Proceedings of XVIII International Conference on Atomic Physics (ICAP2002). 83-90 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 高橋義朗ほか: "イッテルビウム原子のレーザー冷却とその応用"日本物理学会誌. 57・6. 413-416 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K. Honda et al.: "Optical dipole force trapping of a fermion-boson mixture of ytterbium"Phys. Rev. A. 66・2. 021401-1-4(R) (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Enomoto et al.: "Emission spectra of Cs-He excimers in cold helium gas"Phys. Rev. A. 66・4. 042505-1-4 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Takasu et al.: "High-density trapping of cold ytterbium atoms by an optical dipole force"Phys. Rev. Lett.. 90・2. 023003-1-4 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K. Toyoda et al.: "Generation of Bose-Einstein condensates in a well isolated low-pressure vacuum chamber"J. Phys. Soc. Jpn.. 71・6. 1445-1449 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Takahashi et al.: "Photoassociation of laser cooled ytterbium atoms"Proceedings of XVIII International Conference on Atomic Physics(ICAP2002). 83-90 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Takahashi et al.: "Laser cooling of ytterbium atoms and its application"Physical Society of Japan. 57・6. 413-416 (2002)

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      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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