Quantum Statistics and the Viscosity of Spin Polarized LiquidH3e

Thermal Conductivity of Spin-Polarized LiquidHe3

“…The only transport property measured so far as a function of polarization has been the viscosity [17,18]. The most recent measurements [19] show that it increases linearly with m 2 with a slope in agreement with the s-wave prediction [7,9], despite the strong p-wave scattering component. This puzzle calls for the measurement of the thermal conductivity of spin-polarized liquid 3 He.…”

“…To this end, we use the rapid melting technique [20] to produce highly, but transiently, polarized liquid 3 He, and probe its thermal conductivity with a vibrating wire viscometer, previously used to determine the viscosity [19]. Injecting heat into this wire raises the temperature of the surrounding liquid, which we detect through the induced change in viscosity (/1=T 2 at low temperature).…”

Polarization Decreases the Specific Heat of LiquidH3e

“…The thermal time constant of the cell is then obtained from the time dependence of the viscometer temperature. We use the viscometer because, unlike the carbon thermometer also located inside the slit [9], it has no thermal inertia of its own. The viscometer temperature is obtained from the measured viscosity h͑m, T ͒, by computing the viscosity h 0 ͑T ͒ that would be measured in the unpolarized liquid according to h 0 ͑T ͒ h͑m, T ͒͑͞1 1 3m 2 ͒ (appropriate below 100 mK [9]), and converting it to temperature from a separate calibration of h 0 ͑T ͒.…”

“…In order to overcome the low thermal diffusivity of 3 He (D T Ӎ 5 3 10 22 mm 2 ͞s at 100 mK and 27 bars), which would imply long thermal relaxation times with respect to the polarization relaxation time T 1 , we confine 3 He inside a silver sinter. This heat exchanger increases the thermal diffusivity by an order of magnitude, and allows us to couple efficiently the experimental cell to a large heat reservoir (subsequently called heat tank) which limits the temperature rise due to melting [9,10]. The drawback is that we cannot directly measure the specific heat by an adiabatic method [11].…”