Mezzacapo Fabio, Boninsegni Massimo
Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2J1.
Phys Rev Lett. 2006 Jul 28;97(4):045301. doi: 10.1103/PhysRevLett.97.045301. Epub 2006 Jul 25.
Structural and superfluid properties of p-H2 clusters of size up to N=40 molecules, are studied at low temperature (0.5 K<or=T<or=4 K) by path integral Monte Carlo simulations. The superfluid fraction rhoS(T) displays an interesting, nonmonotonic behavior for 22<or=N<or=30. We interpret this dependence in terms of variations with N of the cluster structure. Superfluidity is observed at low T in clusters of as many as 27 molecules; in the temperature range considered here, quantum melting is observed in some clusters, which are seen to freeze at high temperature.
通过路径积分蒙特卡罗模拟，研究了分子数高达N = 40的对氢（p-H2）团簇在低温（0.5K≤T≤4K）下的结构和超流性质。对于22≤N≤30，超流分数ρS(T)呈现出有趣的非单调行为。我们根据团簇结构随N的变化来解释这种依赖性。在多达27个分子的团簇中，在低温下观察到了超流性；在此处考虑的温度范围内，在一些团簇中观察到了量子熔化现象，这些团簇在高温下会冻结。
