Correlation length, finite-geometry effects, and universality in pressurized superfluid helium nearTλ
Correlation length, finite-geometry effects, and universality in pressurized superfluid helium nearTλ
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Tλ 附近加压超流氦的相关长度、有限几何效应和普适性
DOI：
10.1103/physreva.9.1278
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发表时间：
1974
期刊：
影响因子：
--
通讯作者：
F. Pobell
中科院分区：
文献类型：
--
作者：
G. Ihas;F. Pobell
在d= 0.1-、0.2-、0.4-和0.6-μ m宽的通道中，在饱和蒸汽压和熔化曲线之间的压力下，测量了He 4超流性的起始温度T0（P）。通过观察配备有超漏换能器的谐振器中第二声音的消失来检测发作。在所使用的通道中，起始温度T0（P）被降低到低于体转变温度T λ（P）2× 10− 5≤ ε 0≤ 2× 10− 4。这里ε 0= 1− T 0（P）T λ（P）。对于常数d，我们发现ε 0在± 2%的分辨率内与压力无关。根据这些数据计算了方程ε 0=（d d*）-λ′的指数λ′和系数d*，以及相关长度ε = ε * ε-ν′的指数和系数。我们证明了λ′和d*，以及ν′和τ *，以及量τ ρ s T=（0.16±0. 0 1）× 10− 8与压力无关，在± 2%的分辨率范围内。临界指数的压力依赖性的缺乏与普适性的论点是一致的。对于绝对值，我们发现Δ =（1.2±0. 1）× 10− 8 ε− 0.65±0.02，ε 0=[d（5.7±0. 6）× 10− 8]− 1.54±0.05，且Δ ρ s T=（0.16±0. 0 1）× 10− 8。
The onset temperature T 0 (P) for superfluidity of He 4 has been measured in d= 0.1−, 0.2−, 0.4−, and 0.6− μ m wide channels at pressures between saturated vapor pressure and the melting curve. The onset was detected by observing the vanishing of second sound in resonators equipped with superleak transducers. In the channels used the onset temperature T 0 (P) was depressed below the bulk transition temperature T λ (P) by 2× 10− 5≤ ε 0≤ 2× 10− 4. Here ε 0= 1− T 0 (P) T λ (P). For constant d, we find that ε 0 is independent of pressure to within our resolution of±2%. From the data the exponent λ′ and the coefficient d* for the equation ε 0=(d d*)− λ′, and the exponent and coefficient for the correlation length, ξ= ξ* ε− ν′, have been calculated. We show that λ′ and d*, as well as ν′ and ξ*, and the quantity ξ ρ s T=(0.16±0. 0 1)× 10− 8 are independent of pressure, within our resolution of±2%. The lack of a pressure dependence of the critical exponents is in agreement with universality arguments. For the absolute values we find ξ=(1.2±0. 1)× 10− 8 ε− 0.65±0.02, ε 0=[d (5.7±0. 6)× 10− 8]− 1.54±0.05, and ξ ρ s T=(0.16±0. 0 1)× 10− 8.