4 He in Nanoporous Media: 4D XY Quantum Criticality at Finite Temperatures

Tomoyuki Tani, Yusuke Nago, Satoshi Murakawa, Keiya Shirahama

Research output: Contribution to journalArticlepeer-review


We review our study of critical phenomena in superfluid 4He confined in nanoporous glasses. 4He in nanoporous media is an ideal ground to survey the quantum phase transition of bosons. In the present work, critical phenomena were examined using a newly developed hydrodynamic mechanical resonator. The critical exponent of superfluid density ζ was found to be 1.0, in contrast to 0.67 in bulk 4He. We also demonstrate that the superfluid density is proportional to |P-Pc|ζp with ζp= 1 at any finite temperatures. These are the decisive pieces of evidence for the 4D XY criticality, which should have been observed only at 0 K, at finite temperatures. We propose a mechanism of the quantum criticality at finite temperatures in terms of phase alignment among the nanoscale localized Bose condensates (LBECs) in nanopores. The proposed mechanism is discussed in the consideration of the correlation length compared with the quantum effect.

Original languageEnglish
Pages (from-to)449-456
Number of pages8
JournalJournal of Low Temperature Physics
Issue number5-6
Publication statusPublished - 2022 Sept


  • Confined geometries
  • Quantum phase transition
  • Superfluid He

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics


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