Observation of non-classical rotational inertia in bulk solid 4He

Motoshi Kondo, Shunichi Takada, Yoshiyuki Shibayama, Keiya Shirahama

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128 Citations (Scopus)


In recent torsional oscillator experiments by Kim and Chan (KC), a decrease of rotational inertia has been observed in solid 4He in porous materials (Kim, E., Chan, M.H.W. in Nature 427:225, 2004; J. Low Temp. Phys. 138:859, 2005) and in a bulk annular channel (Kim, E., Chan, M.H.W. in Science 305:1941, 2004). This observation strongly suggests the existence of "non-classical rotational inertia" (NCRI), i.e. superflow, in solid 4He. In order to study such a possible "supersolid" phase, we perform torsional oscillator experiments for cylindrical solid 4He samples. We have observed decreases in rotational inertia below 200 mK for two solid samples (pressures P = 4.1 and 3.0 MPa). The observed NCRI fraction at 70 mK is 0.14%, which is about 1/3 of the fraction observed in the annulus by KC. Our observation is the first experimental confirmation of the possible supersolid finding by KC.

Original languageEnglish
Pages (from-to)695-699
Number of pages5
JournalJournal of Low Temperature Physics
Issue number5-6
Publication statusPublished - 2007 Sept


  • 67.80.-s

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics


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