Baumgardner J E, Osheroff D D
Department of Physics, Stanford University, Stanford, California 94305-4060, USA.
Phys Rev Lett. 2004 Oct 8;93(15):155301. doi: 10.1103/PhysRevLett.93.155301. Epub 2004 Oct 4.
We report on continuous-wave NMR measurements of the energy gaps of the A-like and B-like superfluid phases of 3He at 28.4 mT confined to a 99.3% porosity silica aerogel. The gaps are suppressed by the presence of the aerogel in a temperature-independent manner, but the suppression is considerably stronger than expected from the suppression of T(c). We then use our measurements to calculate the free energy ratio between the A-like and B-like phases. The equilibrium AB transition temperature, derived from where this ratio reaches unity, is consistent with previous measurements of the initial displacement of the pinned AB interface on warming. On this basis, we present for the first time the equilibrium phase diagram of the A-like and B-like phases of superfluid 3He in aerogel.
我们报告了在28.4毫特斯拉磁场中，处于99.3%孔隙率二氧化硅气凝胶中的3He的A类和B类超流相能隙的连续波核磁共振测量结果。气凝胶的存在以与温度无关的方式抑制了能隙，但这种抑制比根据Tc的抑制所预期的要强得多。然后我们利用测量结果计算A类和B类相之间的自由能比。从该比值达到1的位置得出的平衡AB转变温度，与先前关于升温时固定的AB界面初始位移的测量结果一致。在此基础上，我们首次给出了气凝胶中超流3He的A类和B类相的平衡相图。
