Positronium in xenon: The path-integral approach.
Positronium in xenon: The path-integral approach.
复制标题
氙中的正电子：路径积分方法。
DOI：
10.1103/physreve.47.2581
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Miller
中科院分区：
文献类型：
--
作者：
Reese;Miller
单个正电子原子在氦中形成半宏观气泡的能力是量子力学的显着表现。当环境条件有利于三重态形成时，三重态的衰变速率急剧下降，从而提供了气泡形成的实验证据。这种现象是在氦的临界点附近观察到的，并且可以通过平均场理论得到很好的解释，在该理论中，正电子原子占据由于其对平均局部密度的影响而引起的局部势阱的基态。由于正电子素原子在产生这种局域态中发挥着积极作用，因此该过程被称为自捕获。对其他稀有气体的类似实验也显示了在液-汽临界点附近自陷的证据，但从扩展行为到局部行为的转变是渐进的。忽略波动的平均场理论在这些较高的温度下并不成功，这表明统计波动强烈影响轻原子状态的分布。本文提出了正电子素在致密惰性气体中的局域化的理论研究，该研究采用路径积分来表示轻原子的平移自由度。它表明，正确解释波动的理论模型能够预测实验测量的主要特征。« less
The ability of a single positronium atom to form a semimacroscopic bubble in helium is a remarkable manifestation of quantum mechanics. Experimental evidence for bubble formation is provided by a dramatic decrease in the decay rate of the triplet state when the ambient conditions favor its formation. The phenomenon is observed near the critical point of helium and is well explained by a mean-field theory in which the positronium atom occupies the ground state of a local potential well induced by its influence on the average local density. Because of the active role played by the positronium atom in producing this localized state, the process is referred to as self-trapping. Similar experiments on other noble gases also show evidence for self-trapping near the liquid-vapor critical point, but the transition from extended to localized behavior is gradual. Mean-field theories, which ignore fluctuations, are not successful at these higher temperatures, suggesting that statistical fluctuations strongly influence the distribution over states of the light atom. This paper presents a theoretical investigation of the localization of positronium in a dense noble gas which employs the path integral to represent the translational degrees of freedom of the light atom. It demonstrates that a theoretical modelmore » which properly accounts for fluctuations is able to predict the main features of the experimental measurements.« less