### Abstract

The superfluidity of liquid ^{3}He in a high-porosity aerogel has been studied using a fourth-sound resonance technique. This technique has two significant advantages: it can directly determine the superfluid density and it can derive the transport properties of the viscous normal-fluid component. The temperature dependence of the resonance frequency revealed suppression of superfluidity and that a finite normal-fluid fraction exists even at T=0. The motion of the normal-fluid component has also been investigated. As T→0, the energy loss becomes very small, despite a finite amount of the normal-fluid component remaining. This implies that the normal-fluid component is highly constrained by the aerogel, and hence the dissipation mechanism cannot be described in terms of the conventional hydrodynamic model. We have succeeded to explain these results by introducing a frictional relaxation model to describe our observations, and found that the flow field changes from being parabolic (Hagen-Poiseuille viscous flow) to flat (Drude frictional flow) on introducing an aerogel. Numerical calculation of the relaxation time using the quasiclassical Green's-function method reproduces experimental results.

Original language | English |
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Article number | 054521 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 82 |

Issue number | 5 |

DOIs | |

Publication status | Published - 2010 Aug 25 |

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### ASJC Scopus subject areas

- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials

### Cite this

*Physical Review B - Condensed Matter and Materials Physics*,

*82*(5), [054521]. https://doi.org/10.1103/PhysRevB.82.054521

**Frictional motion of normal-fluid component of superfluid 3He in aerogel.** / Obara, Ken; Kato, Chiaki; Matsukura, Takaho; Nago, Yusuke; Kado, Ryusuke; Yano, Hideo; Ishikawa, Osamu; Hata, Toru; Higashitani, Seiji; Nagai, Katsuhiko.

Research output: Contribution to journal › Article

*Physical Review B - Condensed Matter and Materials Physics*, vol. 82, no. 5, 054521. https://doi.org/10.1103/PhysRevB.82.054521

}

TY - JOUR

T1 - Frictional motion of normal-fluid component of superfluid 3He in aerogel

AU - Obara, Ken

AU - Kato, Chiaki

AU - Matsukura, Takaho

AU - Nago, Yusuke

AU - Kado, Ryusuke

AU - Yano, Hideo

AU - Ishikawa, Osamu

AU - Hata, Toru

AU - Higashitani, Seiji

AU - Nagai, Katsuhiko

PY - 2010/8/25

Y1 - 2010/8/25

N2 - The superfluidity of liquid 3He in a high-porosity aerogel has been studied using a fourth-sound resonance technique. This technique has two significant advantages: it can directly determine the superfluid density and it can derive the transport properties of the viscous normal-fluid component. The temperature dependence of the resonance frequency revealed suppression of superfluidity and that a finite normal-fluid fraction exists even at T=0. The motion of the normal-fluid component has also been investigated. As T→0, the energy loss becomes very small, despite a finite amount of the normal-fluid component remaining. This implies that the normal-fluid component is highly constrained by the aerogel, and hence the dissipation mechanism cannot be described in terms of the conventional hydrodynamic model. We have succeeded to explain these results by introducing a frictional relaxation model to describe our observations, and found that the flow field changes from being parabolic (Hagen-Poiseuille viscous flow) to flat (Drude frictional flow) on introducing an aerogel. Numerical calculation of the relaxation time using the quasiclassical Green's-function method reproduces experimental results.

AB - The superfluidity of liquid 3He in a high-porosity aerogel has been studied using a fourth-sound resonance technique. This technique has two significant advantages: it can directly determine the superfluid density and it can derive the transport properties of the viscous normal-fluid component. The temperature dependence of the resonance frequency revealed suppression of superfluidity and that a finite normal-fluid fraction exists even at T=0. The motion of the normal-fluid component has also been investigated. As T→0, the energy loss becomes very small, despite a finite amount of the normal-fluid component remaining. This implies that the normal-fluid component is highly constrained by the aerogel, and hence the dissipation mechanism cannot be described in terms of the conventional hydrodynamic model. We have succeeded to explain these results by introducing a frictional relaxation model to describe our observations, and found that the flow field changes from being parabolic (Hagen-Poiseuille viscous flow) to flat (Drude frictional flow) on introducing an aerogel. Numerical calculation of the relaxation time using the quasiclassical Green's-function method reproduces experimental results.

UR - http://www.scopus.com/inward/record.url?scp=77957352293&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77957352293&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.82.054521

DO - 10.1103/PhysRevB.82.054521

M3 - Article

AN - SCOPUS:77957352293

VL - 82

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 5

M1 - 054521

ER -