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Mass coupling and Q -1 of impurity-limited normal 3He in a torsion pendulum

Cornell Affiliated Author(s)


R.G. Bennett
N. Zhelev
A.D. Fefferman
K.Y. Fang
J. Pollanen
P. Sharma
W.P. Halperin
J.M. Parpia


We present results of the Q -1 and period shift, ΔP, for 3He confined in a 98% nominal open aerogel on a torsion pendulum. The aerogel is compressed uniaxially by 10% along a direction aligned to the torsion pendulum axis and was grown within a 400 μm tall pancake (after compression) similar to an Andronikashvili geometry. The result is a high Q pendulum able to resolve Q -1 and mass coupling of the impurity-limited 3He over the whole temperature range. After measuring the empty cell background, we filled the cell above the critical point and observe a temperature dependent period shift, ΔP, between 100 mK and 3 mK that is 2.9% of the period shift (after filling) at 100 mK. The Q -1 due to the 3He decreases by an order of magnitude between 100 mK and 3 mK at a pressure of 0.14±0.03 bar. We compare the observable quantities to the corresponding calculated Q -1 and period shift for bulk 3He. © 2010 Springer Science+Business Media, LLC.

Date Published


Journal of Low Temperature Physics





Number of Pages





Group (Lab)

Jeevak Parpia Group

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