Dehmelt H, Van Dyck R, Palmer F
Department of Physics, University of Washington, Seattle, WA 98195, USA.
Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1681-4. doi: 10.1073/pnas.89.5.1681.
Compositeness of the electron may show up in a very small deviation of the measured electron g factor from one calculated for a point electron by quantum electrodynamics. The precision of our g measurements is currently limited by an interaction of the cyclotron motion with standing waves in the trap cavity containing the electron. The important element introduced here is the systematic exploration of the trap cavity modes and the electron's coupling to them by measuring the shifted electron g factor gc = gc(omega e) as a function of the cyclotron frequency omega e. By measuring gc values at five different omega e values and modeling the trap cavity by six lumped LC circuits, the L values for the four most important modes may be determined and finally the unshifted g value may be extracted. Auxiliary experiments are relied upon only for the L values of the two least critical cavity modes. By designing the trap as a high-Q microwave cavity, an electron cyclotron and anomaly resonance linewidth one or even two orders of magnitude narrower than in free space may be approached without introducing appreciable frequency shifts.
电子的复合性可能会表现为，测量得到的电子g因子与量子电动力学为点电子计算出的g因子存在非常小的偏差。目前，我们对g的测量精度受到回旋运动与包含电子的陷阱腔中驻波相互作用的限制。这里引入的重要因素是，通过测量作为回旋频率ωe函数的频移电子g因子gc = gc(ωe)，对陷阱腔模式及其与电子的耦合进行系统探索。通过测量五个不同ωe值下的gc值，并使用六个集总LC电路对陷阱腔进行建模，可以确定四个最重要模式的L值，最终提取出未频移的g值。仅依靠辅助实验来确定两个最不重要腔模式的L值。通过将陷阱设计为高Q微波腔，可以在不引入明显频移的情况下，使电子回旋和反常共振线宽比自由空间中的窄一个甚至两个数量级。
